/* $NetBSD: resolver.c,v 1.21 2025/01/26 16:25:25 christos Exp $ */ /* * Copyright (C) Internet Systems Consortium, Inc. ("ISC") * * SPDX-License-Identifier: MPL-2.0 * * This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, you can obtain one at https://mozilla.org/MPL/2.0/. * * See the COPYRIGHT file distributed with this work for additional * information regarding copyright ownership. */ /*! \file */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef WANT_QUERYTRACE #define RTRACE(m) \ isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, \ DNS_LOGMODULE_RESOLVER, ISC_LOG_DEBUG(3), "res %p: %s", \ res, (m)) #define RRTRACE(r, m) \ isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, \ DNS_LOGMODULE_RESOLVER, ISC_LOG_DEBUG(3), "res %p: %s", \ (r), (m)) #define FCTXTRACE(m) \ isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, \ DNS_LOGMODULE_RESOLVER, ISC_LOG_DEBUG(3), \ "fctx %p(%s): %s", fctx, fctx->info, (m)) #define FCTXTRACE2(m1, m2) \ isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, \ DNS_LOGMODULE_RESOLVER, ISC_LOG_DEBUG(3), \ "fctx %p(%s): %s %s", fctx, fctx->info, (m1), (m2)) #define FCTXTRACE3(m, res) \ isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, \ DNS_LOGMODULE_RESOLVER, ISC_LOG_DEBUG(3), \ "fctx %p(%s): [result: %s] %s", fctx, fctx->info, \ isc_result_totext(res), (m)) #define FCTXTRACE4(m1, m2, res) \ isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, \ DNS_LOGMODULE_RESOLVER, ISC_LOG_DEBUG(3), \ "fctx %p(%s): [result: %s] %s %s", fctx, fctx->info, \ isc_result_totext(res), (m1), (m2)) #define FCTXTRACE5(m1, m2, v) \ isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, \ DNS_LOGMODULE_RESOLVER, ISC_LOG_DEBUG(3), \ "fctx %p(%s): %s %s%u", fctx, fctx->info, (m1), (m2), \ (v)) #define FTRACE(m) \ isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, \ DNS_LOGMODULE_RESOLVER, ISC_LOG_DEBUG(3), \ "fetch %p (fctx %p(%s)): %s", fetch, fetch->private, \ fetch->private->info, (m)) #define QTRACE(m) \ isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, \ DNS_LOGMODULE_RESOLVER, ISC_LOG_DEBUG(3), \ "resquery %p (fctx %p(%s)): %s", query, query->fctx, \ query->fctx->info, (m)) #else /* ifdef WANT_QUERYTRACE */ #define RTRACE(m) \ do { \ UNUSED(m); \ } while (0) #define RRTRACE(r, m) \ do { \ UNUSED(r); \ UNUSED(m); \ } while (0) #define FCTXTRACE(m) \ do { \ UNUSED(fctx); \ UNUSED(m); \ } while (0) #define FCTXTRACE2(m1, m2) \ do { \ UNUSED(fctx); \ UNUSED(m1); \ UNUSED(m2); \ } while (0) #define FCTXTRACE3(m1, res) \ do { \ UNUSED(fctx); \ UNUSED(m1); \ UNUSED(res); \ } while (0) #define FCTXTRACE4(m1, m2, res) \ do { \ UNUSED(fctx); \ UNUSED(m1); \ UNUSED(m2); \ UNUSED(res); \ } while (0) #define FCTXTRACE5(m1, m2, v) \ do { \ UNUSED(fctx); \ UNUSED(m1); \ UNUSED(m2); \ UNUSED(v); \ } while (0) #define FTRACE(m) \ do { \ UNUSED(m); \ } while (0) #define QTRACE(m) \ do { \ UNUSED(m); \ } while (0) #endif /* WANT_QUERYTRACE */ /* * The maximum time we will wait for a single query. */ #define MAX_SINGLE_QUERY_TIMEOUT 9000U #define MAX_SINGLE_QUERY_TIMEOUT_US (MAX_SINGLE_QUERY_TIMEOUT * US_PER_MS) /* * The default maximum number of validations and validation failures per-fetch */ #ifndef DEFAULT_MAX_VALIDATIONS #define DEFAULT_MAX_VALIDATIONS 16 #endif #ifndef DEFAULT_MAX_VALIDATION_FAILURES #define DEFAULT_MAX_VALIDATION_FAILURES 1 #endif /* * A minumum sane timeout value for the whole query to live when e.g. talking to * a backend server and a quick timeout is preferred by the user. * * IMPORTANT: if changing this value, note there is a documented behavior when * values of 'resolver-query-timeout' less than or equal to 300 are treated as * seconds and converted to milliseconds before applying the limits, that's * why the value of 301 was chosen as the absolute minimum in order to not break * backward compatibility. */ #define MINIMUM_QUERY_TIMEOUT 301U /* * The default time in seconds for the whole query to live. * We want to allow an individual query time to complete / timeout. */ #ifndef DEFAULT_QUERY_TIMEOUT #define DEFAULT_QUERY_TIMEOUT (MAX_SINGLE_QUERY_TIMEOUT + 1000U) #endif /* ifndef DEFAULT_QUERY_TIMEOUT */ /* The maximum time in seconds for the whole query to live. */ #ifndef MAXIMUM_QUERY_TIMEOUT #define MAXIMUM_QUERY_TIMEOUT 30000 #endif /* ifndef MAXIMUM_QUERY_TIMEOUT */ /* The default maximum number of recursions to follow before giving up. */ #ifndef DEFAULT_RECURSION_DEPTH #define DEFAULT_RECURSION_DEPTH 7 #endif /* ifndef DEFAULT_RECURSION_DEPTH */ /* The default maximum number of iterative queries to allow before giving up. */ #ifndef DEFAULT_MAX_QUERIES #define DEFAULT_MAX_QUERIES 50 #endif /* ifndef DEFAULT_MAX_QUERIES */ /* * After NS_FAIL_LIMIT attempts to fetch a name server address, * if the number of addresses in the NS RRset exceeds NS_RR_LIMIT, * stop trying to fetch, in order to avoid wasting resources. */ #define NS_FAIL_LIMIT 4 #define NS_RR_LIMIT 5 /* * IP address lookups are performed for at most NS_PROCESSING_LIMIT NS RRs in * any NS RRset encountered, to avoid excessive resource use while processing * large delegations. */ #define NS_PROCESSING_LIMIT 20 STATIC_ASSERT(NS_PROCESSING_LIMIT > NS_RR_LIMIT, "The maximum number of NS RRs processed for each delegation " "(NS_PROCESSING_LIMIT) must be larger than the large delegation " "threshold (NS_RR_LIMIT)."); /* Hash table for zone counters */ #ifndef RES_DOMAIN_HASH_BITS #define RES_DOMAIN_HASH_BITS 12 #endif /* ifndef RES_DOMAIN_HASH_BITS */ /*% * Maximum EDNS0 input packet size. */ #define RECV_BUFFER_SIZE 4096 /* XXXRTH Constant. */ /*% * This defines the maximum number of timeouts we will permit before we * disable EDNS0 on the query. */ #define MAX_EDNS0_TIMEOUTS 3 typedef struct fetchctx fetchctx_t; typedef struct query { /* Locked by loop event serialization. */ unsigned int magic; isc_refcount_t references; fetchctx_t *fctx; dns_message_t *rmessage; dns_dispatchmgr_t *dispatchmgr; dns_dispatch_t *dispatch; dns_adbaddrinfo_t *addrinfo; isc_time_t start; dns_messageid_t id; dns_dispentry_t *dispentry; ISC_LINK(struct query) link; isc_buffer_t buffer; isc_buffer_t *tsig; dns_tsigkey_t *tsigkey; int ednsversion; unsigned int options; unsigned int attributes; unsigned int udpsize; unsigned char data[512]; } resquery_t; #if DNS_RESOLVER_TRACE #define resquery_ref(ptr) resquery__ref(ptr, __func__, __FILE__, __LINE__) #define resquery_unref(ptr) resquery__unref(ptr, __func__, __FILE__, __LINE__) #define resquery_attach(ptr, ptrp) \ resquery__attach(ptr, ptrp, __func__, __FILE__, __LINE__) #define resquery_detach(ptrp) \ resquery__detach(ptrp, __func__, __FILE__, __LINE__) ISC_REFCOUNT_TRACE_DECL(resquery); #else ISC_REFCOUNT_DECL(resquery); #endif struct tried { isc_sockaddr_t addr; unsigned int count; ISC_LINK(struct tried) link; }; #define QUERY_MAGIC ISC_MAGIC('Q', '!', '!', '!') #define VALID_QUERY(query) ISC_MAGIC_VALID(query, QUERY_MAGIC) #define RESQUERY_ATTR_CANCELED 0x02 #define RESQUERY_CONNECTING(q) ((q)->connects > 0) #define RESQUERY_CANCELED(q) (((q)->attributes & RESQUERY_ATTR_CANCELED) != 0) #define RESQUERY_SENDING(q) ((q)->sends > 0) typedef enum { fetchstate_active, fetchstate_done /*%< Fetch completion events posted. */ } fetchstate_t; typedef enum { badns_unreachable = 0, badns_response, badns_validation, badns_forwarder, } badnstype_t; #define FCTXCOUNT_MAGIC ISC_MAGIC('F', 'C', 'n', 't') #define VALID_FCTXCOUNT(counter) ISC_MAGIC_VALID(counter, FCTXCOUNT_MAGIC) typedef struct fctxcount fctxcount_t; struct fctxcount { unsigned int magic; isc_mem_t *mctx; isc_mutex_t lock; dns_fixedname_t dfname; dns_name_t *domain; uint_fast32_t count; uint_fast32_t allowed; uint_fast32_t dropped; isc_stdtime_t logged; }; struct fetchctx { /*% Not locked. */ unsigned int magic; dns_resolver_t *res; dns_fixedname_t fname; dns_name_t *name; dns_rdatatype_t type; unsigned int options; fctxcount_t *counter; char *info; isc_mem_t *mctx; isc_stdtime_t now; isc_loop_t *loop; unsigned int tid; /* Atomic */ isc_refcount_t references; /*% Locked by lock. */ isc_mutex_t lock; fetchstate_t state; bool hashed; bool cloned; bool spilled; ISC_LINK(struct fetchctx) link; ISC_LIST(dns_fetchresponse_t) resps; /*% Locked by loop event serialization. */ dns_fixedname_t dfname; dns_name_t *domain; dns_rdataset_t nameservers; atomic_uint_fast32_t attributes; isc_timer_t *timer; isc_time_t expires; isc_time_t next_timeout; isc_interval_t interval; dns_message_t *qmessage; ISC_LIST(resquery_t) queries; dns_adbfindlist_t finds; dns_adbfind_t *find; /* * altfinds are names and/or addresses of dual stack servers that * should be used when iterative resolution to a server is not * possible because the address family of that server is not usable. */ dns_adbfindlist_t altfinds; dns_adbfind_t *altfind; dns_adbaddrinfolist_t forwaddrs; dns_adbaddrinfolist_t altaddrs; dns_forwarderlist_t forwarders; dns_fwdpolicy_t fwdpolicy; isc_sockaddrlist_t bad; ISC_LIST(struct tried) edns; isc_sockaddrlist_t bad_edns; dns_validator_t *validator; ISC_LIST(dns_validator_t) validators; dns_db_t *cache; dns_adb_t *adb; bool ns_ttl_ok; uint32_t ns_ttl; isc_counter_t *qc; bool minimized; unsigned int qmin_labels; isc_result_t qmin_warning; bool force_qmin_warning; bool ip6arpaskip; bool forwarding; dns_fixedname_t qminfname; dns_name_t *qminname; dns_rdatatype_t qmintype; dns_fetch_t *qminfetch; dns_rdataset_t qminrrset; dns_fixedname_t qmindcfname; dns_name_t *qmindcname; dns_fixedname_t fwdfname; dns_name_t *fwdname; /*% * The number of events we're waiting for. */ atomic_uint_fast32_t pending; /*% * The number of times we've "restarted" the current * nameserver set. This acts as a failsafe to prevent * us from pounding constantly on a particular set of * servers that, for whatever reason, are not giving * us useful responses, but are responding in such a * way that they are not marked "bad". */ unsigned int restarts; /*% * The number of timeouts that have occurred since we * last successfully received a response packet. This * is used for EDNS0 black hole detection. */ unsigned int timeouts; /*% * Look aside state for DS lookups. */ dns_fixedname_t nsfname; dns_name_t *nsname; dns_fetch_t *nsfetch; dns_rdataset_t nsrrset; /*% * Number of queries that reference this context. */ atomic_uint_fast32_t nqueries; /* Bucket lock. */ /*% * Random numbers to use for mixing up server addresses. */ uint32_t rand_buf; uint32_t rand_bits; /*% * Fetch-local statistics for detailed logging. */ isc_result_t result; /*%< fetch result */ isc_result_t vresult; /*%< validation result */ isc_time_t start; uint64_t duration; bool logged; unsigned int querysent; unsigned int referrals; unsigned int lamecount; unsigned int quotacount; unsigned int neterr; unsigned int badresp; unsigned int adberr; unsigned int findfail; unsigned int valfail; bool timeout; dns_adbaddrinfo_t *addrinfo; unsigned int depth; char clientstr[ISC_SOCKADDR_FORMATSIZE]; uint32_t nvalidations; uint32_t nfails; }; #define FCTX_MAGIC ISC_MAGIC('F', '!', '!', '!') #define VALID_FCTX(fctx) ISC_MAGIC_VALID(fctx, FCTX_MAGIC) #define FCTX_ATTR_HAVEANSWER 0x0001 #define FCTX_ATTR_GLUING 0x0002 #define FCTX_ATTR_ADDRWAIT 0x0004 #define FCTX_ATTR_WANTCACHE 0x0010 #define FCTX_ATTR_WANTNCACHE 0x0020 #define FCTX_ATTR_NEEDEDNS0 0x0040 #define FCTX_ATTR_TRIEDFIND 0x0080 #define FCTX_ATTR_TRIEDALT 0x0100 #define HAVE_ANSWER(f) \ ((atomic_load_acquire(&(f)->attributes) & FCTX_ATTR_HAVEANSWER) != 0) #define GLUING(f) \ ((atomic_load_acquire(&(f)->attributes) & FCTX_ATTR_GLUING) != 0) #define ADDRWAIT(f) \ ((atomic_load_acquire(&(f)->attributes) & FCTX_ATTR_ADDRWAIT) != 0) #define SHUTTINGDOWN(f) ((f)->state == fetchstate_done) #define WANTCACHE(f) \ ((atomic_load_acquire(&(f)->attributes) & FCTX_ATTR_WANTCACHE) != 0) #define WANTNCACHE(f) \ ((atomic_load_acquire(&(f)->attributes) & FCTX_ATTR_WANTNCACHE) != 0) #define NEEDEDNS0(f) \ ((atomic_load_acquire(&(f)->attributes) & FCTX_ATTR_NEEDEDNS0) != 0) #define TRIEDFIND(f) \ ((atomic_load_acquire(&(f)->attributes) & FCTX_ATTR_TRIEDFIND) != 0) #define TRIEDALT(f) \ ((atomic_load_acquire(&(f)->attributes) & FCTX_ATTR_TRIEDALT) != 0) #define FCTX_ATTR_SET(f, a) atomic_fetch_or_release(&(f)->attributes, (a)) #define FCTX_ATTR_CLR(f, a) atomic_fetch_and_release(&(f)->attributes, ~(a)) typedef struct { dns_adbaddrinfo_t *addrinfo; fetchctx_t *fctx; } dns_valarg_t; struct dns_fetch { unsigned int magic; isc_mem_t *mctx; dns_resolver_t *res; fetchctx_t *private; }; #define DNS_FETCH_MAGIC ISC_MAGIC('F', 't', 'c', 'h') #define DNS_FETCH_VALID(fetch) ISC_MAGIC_VALID(fetch, DNS_FETCH_MAGIC) typedef struct alternate { bool isaddress; union { isc_sockaddr_t addr; struct { dns_name_t name; in_port_t port; } _n; } _u; ISC_LINK(struct alternate) link; } alternate_t; struct dns_resolver { /* Unlocked. */ unsigned int magic; isc_mem_t *mctx; isc_mutex_t lock; isc_mutex_t primelock; dns_rdataclass_t rdclass; isc_loopmgr_t *loopmgr; isc_nm_t *nm; dns_view_t *view; bool frozen; unsigned int options; isc_tlsctx_cache_t *tlsctx_cache; dns_dispatchset_t *dispatches4; dns_dispatchset_t *dispatches6; isc_hashmap_t *fctxs; isc_rwlock_t fctxs_lock; isc_hashmap_t *counters; isc_rwlock_t counters_lock; uint32_t lame_ttl; ISC_LIST(alternate_t) alternates; dns_nametree_t *algorithms; dns_nametree_t *digests; dns_nametree_t *mustbesecure; unsigned int spillatmax; unsigned int spillatmin; isc_timer_t *spillattimer; bool zero_no_soa_ttl; unsigned int query_timeout; unsigned int maxdepth; unsigned int maxqueries; isc_result_t quotaresp[2]; isc_stats_t *stats; dns_stats_t *querystats; /* Additions for serve-stale feature. */ unsigned int retryinterval; /* in milliseconds */ unsigned int nonbackofftries; /* Atomic */ isc_refcount_t references; atomic_uint_fast32_t zspill; /* fetches-per-zone */ atomic_bool exiting; atomic_bool priming; atomic_uint_fast32_t maxvalidations; atomic_uint_fast32_t maxvalidationfails; /* Locked by lock. */ unsigned int spillat; /* clients-per-query */ /* Locked by primelock. */ dns_fetch_t *primefetch; /* Atomic. */ atomic_uint_fast32_t nfctx; uint32_t nloops; isc_mempool_t **namepools; isc_mempool_t **rdspools; }; #define RES_MAGIC ISC_MAGIC('R', 'e', 's', '!') #define VALID_RESOLVER(res) ISC_MAGIC_VALID(res, RES_MAGIC) /*% * Private addrinfo flags. */ enum { FCTX_ADDRINFO_MARK = 1 << 0, FCTX_ADDRINFO_FORWARDER = 1 << 1, FCTX_ADDRINFO_EDNSOK = 1 << 2, FCTX_ADDRINFO_NOCOOKIE = 1 << 3, FCTX_ADDRINFO_BADCOOKIE = 1 << 4, FCTX_ADDRINFO_DUALSTACK = 1 << 5, FCTX_ADDRINFO_NOEDNS0 = 1 << 6, }; #define UNMARKED(a) (((a)->flags & FCTX_ADDRINFO_MARK) == 0) #define ISFORWARDER(a) (((a)->flags & FCTX_ADDRINFO_FORWARDER) != 0) #define NOCOOKIE(a) (((a)->flags & FCTX_ADDRINFO_NOCOOKIE) != 0) #define EDNSOK(a) (((a)->flags & FCTX_ADDRINFO_EDNSOK) != 0) #define BADCOOKIE(a) (((a)->flags & FCTX_ADDRINFO_BADCOOKIE) != 0) #define ISDUALSTACK(a) (((a)->flags & FCTX_ADDRINFO_DUALSTACK) != 0) #define NXDOMAIN(r) (((r)->attributes & DNS_RDATASETATTR_NXDOMAIN) != 0) #define NEGATIVE(r) (((r)->attributes & DNS_RDATASETATTR_NEGATIVE) != 0) #define STATICSTUB(r) (((r)->attributes & DNS_RDATASETATTR_STATICSTUB) != 0) #ifdef ENABLE_AFL bool dns_fuzzing_resolver = false; void dns_resolver_setfuzzing(void) { dns_fuzzing_resolver = true; } #endif /* ifdef ENABLE_AFL */ static unsigned char ip6_arpa_data[] = "\003IP6\004ARPA"; static unsigned char ip6_arpa_offsets[] = { 0, 4, 9 }; static const dns_name_t ip6_arpa = DNS_NAME_INITABSOLUTE(ip6_arpa_data, ip6_arpa_offsets); static void dns_resolver__destroy(dns_resolver_t *res); static isc_result_t resquery_send(resquery_t *query); static void resquery_response(isc_result_t eresult, isc_region_t *region, void *arg); static void resquery_response_continue(void *arg, isc_result_t result); static void resquery_connected(isc_result_t eresult, isc_region_t *region, void *arg); static void fctx_try(fetchctx_t *fctx, bool retrying); static void fctx_shutdown(void *arg); static void fctx_minimize_qname(fetchctx_t *fctx); static void fctx_destroy(fetchctx_t *fctx); static isc_result_t ncache_adderesult(dns_message_t *message, dns_db_t *cache, dns_dbnode_t *node, dns_rdatatype_t covers, isc_stdtime_t now, dns_ttl_t minttl, dns_ttl_t maxttl, bool optout, bool secure, dns_rdataset_t *ardataset, isc_result_t *eresultp); static void validated(void *arg); static void maybe_cancel_validators(fetchctx_t *fctx); static void add_bad(fetchctx_t *fctx, dns_message_t *rmessage, dns_adbaddrinfo_t *addrinfo, isc_result_t reason, badnstype_t badtype); static isc_result_t findnoqname(fetchctx_t *fctx, dns_message_t *message, dns_name_t *name, dns_rdatatype_t type, dns_name_t **noqname); #define fctx_done_detach(fctxp, result) \ if (fctx__done(*fctxp, result, __func__, __FILE__, __LINE__)) { \ fetchctx_detach(fctxp); \ } #define fctx_done_unref(fctx, result) \ if (fctx__done(fctx, result, __func__, __FILE__, __LINE__)) { \ fetchctx_unref(fctx); \ } #if DNS_RESOLVER_TRACE #define fetchctx_ref(ptr) fetchctx__ref(ptr, __func__, __FILE__, __LINE__) #define fetchctx_unref(ptr) fetchctx__unref(ptr, __func__, __FILE__, __LINE__) #define fetchctx_attach(ptr, ptrp) \ fetchctx__attach(ptr, ptrp, __func__, __FILE__, __LINE__) #define fetchctx_detach(ptrp) \ fetchctx__detach(ptrp, __func__, __FILE__, __LINE__) ISC_REFCOUNT_TRACE_DECL(fetchctx); #else ISC_REFCOUNT_DECL(fetchctx); #endif static bool fctx__done(fetchctx_t *fctx, isc_result_t result, const char *func, const char *file, unsigned int line); static void resume_qmin(void *arg); static isc_result_t get_attached_fctx(dns_resolver_t *res, isc_loop_t *loop, const dns_name_t *name, dns_rdatatype_t type, const dns_name_t *domain, dns_rdataset_t *nameservers, const isc_sockaddr_t *client, unsigned int options, unsigned int depth, isc_counter_t *qc, fetchctx_t **fctxp, bool *new_fctx); static void release_fctx(fetchctx_t *fctx); /*% * The structure and functions defined below implement the resolver * query (resquery) response handling logic. * * When a resolver query is sent and a response is received, the * resquery_response() event handler is run, which calls the rctx_*() * functions. The respctx_t structure maintains state from function * to function. * * The call flow is described below: * * 1. resquery_response(): * - Initialize a respctx_t structure (rctx_respinit()). * - Check for dispatcher failure (rctx_dispfail()). * - Parse the response (rctx_parse()). * - Log the response (rctx_logpacket()). * - Check the parsed response for an OPT record and handle * EDNS (rctx_opt(), rctx_edns()). * - Check for a bad or lame server (rctx_badserver(), rctx_lameserver()). * - If RCODE and ANCOUNT suggest this is a positive answer, and * if so, call rctx_answer(): go to step 2. * - If RCODE and NSCOUNT suggest this is a negative answer or a * referral, call rctx_answer_none(): go to step 4. * - Check the additional section for data that should be cached * (rctx_additional()). * - Clean up and finish by calling rctx_done(): go to step 5. * * 2. rctx_answer(): * - If the answer appears to be positive, call rctx_answer_positive(): * go to step 3. * - If the response is a malformed delegation (with glue or NS records * in the answer section), call rctx_answer_none(): go to step 4. * * 3. rctx_answer_positive(): * - Initialize the portions of respctx_t needed for processing an answer * (rctx_answer_init()). * - Scan the answer section to find records that are responsive to the * query (rctx_answer_scan()). * - For whichever type of response was found, call a separate routine * to handle it: matching QNAME/QTYPE (rctx_answer_match()), * CNAME (rctx_answer_cname()), covering DNAME (rctx_answer_dname()), * or any records returned in response to a query of type ANY * (rctx_answer_any()). * - Scan the authority section for NS or other records that may be * included with a positive answer (rctx_authority_scan()). * * 4. rctx_answer_none(): * - Determine whether this is an NXDOMAIN, NXRRSET, or referral. * - If referral, set up the resolver to follow the delegation * (rctx_referral()). * - If NXDOMAIN/NXRRSET, scan the authority section for NS and SOA * records included with a negative response (rctx_authority_negative()), * then for DNSSEC proof of nonexistence (rctx_authority_dnssec()). * * 5. rctx_done(): * - Set up chasing of DS records if needed (rctx_chaseds()). * - If the response wasn't intended for us, wait for another response * from the dispatcher (rctx_next()). * - If there is a problem with the responding server, set up another * query to a different server (rctx_nextserver()). * - If there is a problem that might be temporary or dependent on * EDNS options, set up another query to the same server with changed * options (rctx_resend()). * - Shut down the fetch context. */ typedef struct respctx { resquery_t *query; fetchctx_t *fctx; isc_mem_t *mctx; isc_result_t result; isc_buffer_t buffer; unsigned int retryopts; /* updated options to pass to * fctx_query() when resending */ dns_rdatatype_t type; /* type being sought (set to * ANY if qtype was SIG or RRSIG) */ bool aa; /* authoritative answer? */ dns_trust_t trust; /* answer trust level */ bool chaining; /* CNAME/DNAME processing? */ bool next_server; /* give up, try the next server * */ badnstype_t broken_type; /* type of name server problem * */ isc_result_t broken_server; bool get_nameservers; /* get a new NS rrset at * zone cut? */ bool resend; /* resend this query? */ bool nextitem; /* invalid response; keep * listening for the correct one */ bool truncated; /* response was truncated */ bool no_response; /* no response was received */ bool glue_in_answer; /* glue may be in the answer * section */ bool ns_in_answer; /* NS may be in the answer * section */ bool negative; /* is this a negative response? */ isc_stdtime_t now; /* time info */ isc_time_t tnow; isc_time_t *finish; unsigned int dname_labels; unsigned int domain_labels; /* range of permissible number * of * labels in a DNAME */ dns_name_t *aname; /* answer name */ dns_rdataset_t *ardataset; /* answer rdataset */ dns_name_t *cname; /* CNAME name */ dns_rdataset_t *crdataset; /* CNAME rdataset */ dns_name_t *dname; /* DNAME name */ dns_rdataset_t *drdataset; /* DNAME rdataset */ dns_name_t *ns_name; /* NS name */ dns_rdataset_t *ns_rdataset; /* NS rdataset */ dns_name_t *soa_name; /* SOA name in a negative answer */ dns_name_t *ds_name; /* DS name in a negative answer */ dns_name_t *found_name; /* invalid name in negative * response */ dns_rdatatype_t found_type; /* invalid type in negative * response */ dns_rdataset_t *opt; /* OPT rdataset */ } respctx_t; static void rctx_respinit(resquery_t *query, fetchctx_t *fctx, isc_result_t result, isc_region_t *region, respctx_t *rctx); static void rctx_answer_init(respctx_t *rctx); static void rctx_answer_scan(respctx_t *rctx); static void rctx_authority_positive(respctx_t *rctx); static isc_result_t rctx_answer_any(respctx_t *rctx); static isc_result_t rctx_answer_match(respctx_t *rctx); static isc_result_t rctx_answer_cname(respctx_t *rctx); static isc_result_t rctx_answer_dname(respctx_t *rctx); static isc_result_t rctx_answer_positive(respctx_t *rctx); static isc_result_t rctx_authority_negative(respctx_t *rctx); static isc_result_t rctx_authority_dnssec(respctx_t *rctx); static void rctx_additional(respctx_t *rctx); static isc_result_t rctx_referral(respctx_t *rctx); static isc_result_t rctx_answer_none(respctx_t *rctx); static void rctx_nextserver(respctx_t *rctx, dns_message_t *message, dns_adbaddrinfo_t *addrinfo, isc_result_t result); static void rctx_resend(respctx_t *rctx, dns_adbaddrinfo_t *addrinfo); static isc_result_t rctx_next(respctx_t *rctx); static void rctx_chaseds(respctx_t *rctx, dns_message_t *message, dns_adbaddrinfo_t *addrinfo, isc_result_t result); static void rctx_done(respctx_t *rctx, isc_result_t result); static void rctx_logpacket(respctx_t *rctx); static void rctx_opt(respctx_t *rctx); static void rctx_edns(respctx_t *rctx); static isc_result_t rctx_parse(respctx_t *rctx); static isc_result_t rctx_badserver(respctx_t *rctx, isc_result_t result); static isc_result_t rctx_answer(respctx_t *rctx); static isc_result_t rctx_lameserver(respctx_t *rctx); static isc_result_t rctx_dispfail(respctx_t *rctx); static isc_result_t rctx_timedout(respctx_t *rctx); static void rctx_ncache(respctx_t *rctx); /*% * Increment resolver-related statistics counters. */ static void inc_stats(dns_resolver_t *res, isc_statscounter_t counter) { if (res->stats != NULL) { isc_stats_increment(res->stats, counter); } } static void dec_stats(dns_resolver_t *res, isc_statscounter_t counter) { if (res->stats != NULL) { isc_stats_decrement(res->stats, counter); } } static void set_stats(dns_resolver_t *res, isc_statscounter_t counter, uint64_t val) { if (res->stats != NULL) { isc_stats_set(res->stats, val, counter); } } static isc_result_t valcreate(fetchctx_t *fctx, dns_message_t *message, dns_adbaddrinfo_t *addrinfo, dns_name_t *name, dns_rdatatype_t type, dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset, unsigned int valoptions) { dns_validator_t *validator = NULL; dns_valarg_t *valarg = NULL; isc_result_t result; valarg = isc_mem_get(fctx->mctx, sizeof(*valarg)); *valarg = (dns_valarg_t){ .addrinfo = addrinfo, }; fetchctx_attach(fctx, &valarg->fctx); if (!ISC_LIST_EMPTY(fctx->validators)) { valoptions |= DNS_VALIDATOR_DEFER; } else { valoptions &= ~DNS_VALIDATOR_DEFER; } result = dns_validator_create( fctx->res->view, name, type, rdataset, sigrdataset, message, valoptions, fctx->loop, validated, valarg, &fctx->nvalidations, &fctx->nfails, fctx->qc, &validator); RUNTIME_CHECK(result == ISC_R_SUCCESS); inc_stats(fctx->res, dns_resstatscounter_val); if ((valoptions & DNS_VALIDATOR_DEFER) == 0) { INSIST(fctx->validator == NULL); fctx->validator = validator; } ISC_LIST_APPEND(fctx->validators, validator, link); return ISC_R_SUCCESS; } static void resquery_destroy(resquery_t *query) { fetchctx_t *fctx = query->fctx; query->magic = 0; if (ISC_LINK_LINKED(query, link)) { ISC_LIST_UNLINK(fctx->queries, query, link); } if (query->tsig != NULL) { isc_buffer_free(&query->tsig); } if (query->tsigkey != NULL) { dns_tsigkey_detach(&query->tsigkey); } if (query->dispentry != NULL) { dns_dispatch_done(&query->dispentry); } if (query->dispatch != NULL) { dns_dispatch_detach(&query->dispatch); } LOCK(&fctx->lock); atomic_fetch_sub_release(&fctx->nqueries, 1); UNLOCK(&fctx->lock); if (query->rmessage != NULL) { dns_message_detach(&query->rmessage); } isc_mem_put(fctx->mctx, query, sizeof(*query)); fetchctx_detach(&fctx); } #if DNS_RESOLVER_TRACE ISC_REFCOUNT_TRACE_IMPL(resquery, resquery_destroy); #else ISC_REFCOUNT_IMPL(resquery, resquery_destroy); #endif /*% * Update EDNS statistics for a server after not getting a response to a UDP * query sent to it. */ static void update_edns_stats(resquery_t *query) { fetchctx_t *fctx = query->fctx; if ((query->options & DNS_FETCHOPT_TCP) != 0) { return; } if ((query->options & DNS_FETCHOPT_NOEDNS0) == 0) { dns_adb_ednsto(fctx->adb, query->addrinfo); } else { dns_adb_timeout(fctx->adb, query->addrinfo); } } static void fctx_expired(void *arg); /* * Start the maximum lifetime timer for the fetch. This will * trigger if, for example, some ADB or validator dependency * loop occurs and causes a fetch to hang. */ static void fctx_starttimer(fetchctx_t *fctx) { isc_interval_t interval; isc_time_t now; isc_time_t expires; isc_interval_set(&interval, 2, 0); isc_time_add(&fctx->expires, &interval, &expires); now = isc_time_now(); if (isc_time_compare(&expires, &now) <= 0) { isc_interval_set(&interval, 0, 1); } else { isc_time_subtract(&expires, &now, &interval); } isc_timer_start(fctx->timer, isc_timertype_once, &interval); } static void fctx_stoptimer(fetchctx_t *fctx) { isc_timer_stop(fctx->timer); } static void fctx_cancelquery(resquery_t **queryp, isc_time_t *finish, bool no_response, bool age_untried) { resquery_t *query = NULL; fetchctx_t *fctx = NULL; dns_adbfind_t *find = NULL; dns_adbaddrinfo_t *addrinfo; isc_stdtime_t now = isc_stdtime_now(); REQUIRE(queryp != NULL); query = *queryp; fctx = query->fctx; if (RESQUERY_CANCELED(query)) { return; } FCTXTRACE("cancelquery"); query->attributes |= RESQUERY_ATTR_CANCELED; /* * Should we update the RTT? */ if (finish != NULL || no_response) { unsigned int rtt, factor; if (finish != NULL) { /* * We have both the start and finish times for this * packet, so we can compute a real RTT. */ unsigned int rttms; rtt = (unsigned int)isc_time_microdiff(finish, &query->start); rttms = rtt / US_PER_MS; factor = DNS_ADB_RTTADJDEFAULT; if (rttms < DNS_RESOLVER_QRYRTTCLASS0) { inc_stats(fctx->res, dns_resstatscounter_queryrtt0); } else if (rttms < DNS_RESOLVER_QRYRTTCLASS1) { inc_stats(fctx->res, dns_resstatscounter_queryrtt1); } else if (rttms < DNS_RESOLVER_QRYRTTCLASS2) { inc_stats(fctx->res, dns_resstatscounter_queryrtt2); } else if (rttms < DNS_RESOLVER_QRYRTTCLASS3) { inc_stats(fctx->res, dns_resstatscounter_queryrtt3); } else if (rttms < DNS_RESOLVER_QRYRTTCLASS4) { inc_stats(fctx->res, dns_resstatscounter_queryrtt4); } else { inc_stats(fctx->res, dns_resstatscounter_queryrtt5); } } else { uint32_t value; uint32_t mask; update_edns_stats(query); /* * If "forward first;" is used and a forwarder timed * out, do not attempt to query it again in this fetch * context. */ if (fctx->fwdpolicy == dns_fwdpolicy_first && ISFORWARDER(query->addrinfo)) { add_bad(fctx, query->rmessage, query->addrinfo, ISC_R_TIMEDOUT, badns_forwarder); } /* * We don't have an RTT for this query. Maybe the * packet was lost, or maybe this server is very * slow. We don't know. Increase the RTT. */ INSIST(no_response); value = isc_random32(); if (query->addrinfo->srtt > 800000) { mask = 0x3fff; } else if (query->addrinfo->srtt > 400000) { mask = 0x7fff; } else if (query->addrinfo->srtt > 200000) { mask = 0xffff; } else if (query->addrinfo->srtt > 100000) { mask = 0x1ffff; } else if (query->addrinfo->srtt > 50000) { mask = 0x3ffff; } else if (query->addrinfo->srtt > 25000) { mask = 0x7ffff; } else { mask = 0xfffff; } /* * Don't adjust timeout on EDNS queries unless we have * seen a EDNS response. */ if ((query->options & DNS_FETCHOPT_NOEDNS0) == 0 && !EDNSOK(query->addrinfo)) { mask >>= 2; } rtt = query->addrinfo->srtt + (value & mask); if (rtt > MAX_SINGLE_QUERY_TIMEOUT_US) { rtt = MAX_SINGLE_QUERY_TIMEOUT_US; } if (rtt > fctx->res->query_timeout * US_PER_MS) { rtt = fctx->res->query_timeout * US_PER_MS; } /* * Replace the current RTT with our value. */ factor = DNS_ADB_RTTADJREPLACE; } dns_adb_adjustsrtt(fctx->adb, query->addrinfo, rtt, factor); } if ((query->options & DNS_FETCHOPT_TCP) == 0) { /* Inform the ADB that we're ending a UDP fetch */ dns_adb_endudpfetch(fctx->adb, query->addrinfo); } /* * Age RTTs of servers not tried. */ if (finish != NULL || age_untried) { for (addrinfo = ISC_LIST_HEAD(fctx->forwaddrs); addrinfo != NULL; addrinfo = ISC_LIST_NEXT(addrinfo, publink)) { if (UNMARKED(addrinfo)) { dns_adb_agesrtt(fctx->adb, addrinfo, now); } } } if ((finish != NULL || age_untried) && TRIEDFIND(fctx)) { for (find = ISC_LIST_HEAD(fctx->finds); find != NULL; find = ISC_LIST_NEXT(find, publink)) { for (addrinfo = ISC_LIST_HEAD(find->list); addrinfo != NULL; addrinfo = ISC_LIST_NEXT(addrinfo, publink)) { if (UNMARKED(addrinfo)) { dns_adb_agesrtt(fctx->adb, addrinfo, now); } } } } if ((finish != NULL || age_untried) && TRIEDALT(fctx)) { for (addrinfo = ISC_LIST_HEAD(fctx->altaddrs); addrinfo != NULL; addrinfo = ISC_LIST_NEXT(addrinfo, publink)) { if (UNMARKED(addrinfo)) { dns_adb_agesrtt(fctx->adb, addrinfo, now); } } for (find = ISC_LIST_HEAD(fctx->altfinds); find != NULL; find = ISC_LIST_NEXT(find, publink)) { for (addrinfo = ISC_LIST_HEAD(find->list); addrinfo != NULL; addrinfo = ISC_LIST_NEXT(addrinfo, publink)) { if (UNMARKED(addrinfo)) { dns_adb_agesrtt(fctx->adb, addrinfo, now); } } } } /* * Check for any outstanding dispatch responses and if they * exist, cancel them. */ if (query->dispentry != NULL) { dns_dispatch_done(&query->dispentry); } LOCK(&fctx->lock); if (ISC_LINK_LINKED(query, link)) { ISC_LIST_UNLINK(fctx->queries, query, link); } UNLOCK(&fctx->lock); resquery_detach(queryp); } static void fctx_cleanup(fetchctx_t *fctx) { dns_adbfind_t *find = NULL, *next_find = NULL; dns_adbaddrinfo_t *addr = NULL, *next_addr = NULL; REQUIRE(ISC_LIST_EMPTY(fctx->queries)); for (find = ISC_LIST_HEAD(fctx->finds); find != NULL; find = next_find) { next_find = ISC_LIST_NEXT(find, publink); ISC_LIST_UNLINK(fctx->finds, find, publink); dns_adb_destroyfind(&find); fetchctx_unref(fctx); } fctx->find = NULL; for (find = ISC_LIST_HEAD(fctx->altfinds); find != NULL; find = next_find) { next_find = ISC_LIST_NEXT(find, publink); ISC_LIST_UNLINK(fctx->altfinds, find, publink); dns_adb_destroyfind(&find); fetchctx_unref(fctx); } fctx->altfind = NULL; for (addr = ISC_LIST_HEAD(fctx->forwaddrs); addr != NULL; addr = next_addr) { next_addr = ISC_LIST_NEXT(addr, publink); ISC_LIST_UNLINK(fctx->forwaddrs, addr, publink); dns_adb_freeaddrinfo(fctx->adb, &addr); } for (addr = ISC_LIST_HEAD(fctx->altaddrs); addr != NULL; addr = next_addr) { next_addr = ISC_LIST_NEXT(addr, publink); ISC_LIST_UNLINK(fctx->altaddrs, addr, publink); dns_adb_freeaddrinfo(fctx->adb, &addr); } } static void fctx_cancelqueries(fetchctx_t *fctx, bool no_response, bool age_untried) { resquery_t *query = NULL, *next_query = NULL; ISC_LIST(resquery_t) queries; FCTXTRACE("cancelqueries"); ISC_LIST_INIT(queries); /* * Move the queries to a local list so we can cancel * them without holding the lock. */ LOCK(&fctx->lock); ISC_LIST_MOVE(queries, fctx->queries); UNLOCK(&fctx->lock); for (query = ISC_LIST_HEAD(queries); query != NULL; query = next_query) { next_query = ISC_LIST_NEXT(query, link); /* * Note that we have to unlink the query here, * because if it's still linked in fctx_cancelquery(), * then it will try to unlink it from fctx->queries. */ ISC_LIST_UNLINK(queries, query, link); fctx_cancelquery(&query, NULL, no_response, age_untried); } } static void fcount_logspill(fetchctx_t *fctx, fctxcount_t *counter, bool final) { char dbuf[DNS_NAME_FORMATSIZE]; isc_stdtime_t now; if (!isc_log_wouldlog(dns_lctx, ISC_LOG_INFO)) { return; } /* Do not log a message if there were no dropped fetches. */ if (counter->dropped == 0) { return; } /* Do not log the cumulative message if the previous log is recent. */ now = isc_stdtime_now(); if (!final && counter->logged > now - 60) { return; } dns_name_format(fctx->domain, dbuf, sizeof(dbuf)); if (!final) { isc_log_write(dns_lctx, DNS_LOGCATEGORY_SPILL, DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO, "too many simultaneous fetches for %s " "(allowed %" PRIuFAST32 " spilled %" PRIuFAST32 "; %s)", dbuf, counter->allowed, counter->dropped, counter->dropped == 1 ? "initial trigger event" : "cumulative since " "initial trigger event"); } else { isc_log_write(dns_lctx, DNS_LOGCATEGORY_SPILL, DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO, "fetch counters for %s now being discarded " "(allowed %" PRIuFAST32 " spilled %" PRIuFAST32 "; cumulative since initial trigger event)", dbuf, counter->allowed, counter->dropped); } counter->logged = now; } static bool fcount_match(void *node, const void *key) { const fctxcount_t *counter = node; const dns_name_t *domain = key; return dns_name_equal(counter->domain, domain); } static isc_result_t fcount_incr(fetchctx_t *fctx, bool force) { isc_result_t result = ISC_R_SUCCESS; dns_resolver_t *res = NULL; fctxcount_t *counter = NULL; uint32_t hashval; uint_fast32_t spill; isc_rwlocktype_t locktype = isc_rwlocktype_read; REQUIRE(fctx != NULL); res = fctx->res; REQUIRE(res != NULL); INSIST(fctx->counter == NULL); /* Skip any counting if fetches-per-zone is disabled */ spill = atomic_load_acquire(&res->zspill); if (spill == 0) { return ISC_R_SUCCESS; } hashval = dns_name_hash(fctx->domain); RWLOCK(&res->counters_lock, locktype); result = isc_hashmap_find(res->counters, hashval, fcount_match, fctx->domain, (void **)&counter); switch (result) { case ISC_R_SUCCESS: break; case ISC_R_NOTFOUND: counter = isc_mem_get(fctx->mctx, sizeof(*counter)); *counter = (fctxcount_t){ .magic = FCTXCOUNT_MAGIC, .count = 0, .allowed = 0, }; isc_mem_attach(fctx->mctx, &counter->mctx); isc_mutex_init(&counter->lock); counter->domain = dns_fixedname_initname(&counter->dfname); dns_name_copy(fctx->domain, counter->domain); UPGRADELOCK(&res->counters_lock, locktype); void *found = NULL; result = isc_hashmap_add(res->counters, hashval, fcount_match, counter->domain, counter, &found); if (result == ISC_R_EXISTS) { isc_mutex_destroy(&counter->lock); isc_mem_putanddetach(&counter->mctx, counter, sizeof(*counter)); counter = found; result = ISC_R_SUCCESS; } INSIST(result == ISC_R_SUCCESS); break; default: UNREACHABLE(); } INSIST(VALID_FCTXCOUNT(counter)); INSIST(spill > 0); LOCK(&counter->lock); if (++counter->count > spill && !force) { counter->count--; INSIST(counter->count > 0); counter->dropped++; fcount_logspill(fctx, counter, false); result = ISC_R_QUOTA; } else { counter->allowed++; fctx->counter = counter; } UNLOCK(&counter->lock); RWUNLOCK(&res->counters_lock, locktype); return result; } static bool match_ptr(void *node, const void *key) { return node == key; } static void fcount_decr(fetchctx_t *fctx) { REQUIRE(fctx != NULL); fctxcount_t *counter = fctx->counter; if (counter == NULL) { return; } fctx->counter = NULL; /* * FIXME: This should not require a write lock, but should be * implemented using reference counting later, otherwise we would could * encounter ABA problem here - the count could go up and down when we * switch from read to write lock. */ RWLOCK(&fctx->res->counters_lock, isc_rwlocktype_write); LOCK(&counter->lock); INSIST(VALID_FCTXCOUNT(counter)); INSIST(counter->count > 0); if (--counter->count > 0) { UNLOCK(&counter->lock); RWUNLOCK(&fctx->res->counters_lock, isc_rwlocktype_write); return; } isc_result_t result = isc_hashmap_delete(fctx->res->counters, dns_name_hash(counter->domain), match_ptr, counter); INSIST(result == ISC_R_SUCCESS); fcount_logspill(fctx, counter, true); UNLOCK(&counter->lock); isc_mutex_destroy(&counter->lock); isc_mem_putanddetach(&counter->mctx, counter, sizeof(*counter)); RWUNLOCK(&fctx->res->counters_lock, isc_rwlocktype_write); } static void spillattimer_countdown(void *arg); static void fctx_sendevents(fetchctx_t *fctx, isc_result_t result) { dns_fetchresponse_t *resp = NULL, *next = NULL; unsigned int count = 0; bool logit = false; isc_time_t now; unsigned int old_spillat; unsigned int new_spillat = 0; /* initialized to silence * compiler warnings */ LOCK(&fctx->lock); REQUIRE(fctx->state == fetchstate_done); FCTXTRACE("sendevents"); /* * Keep some record of fetch result for logging later (if required). */ fctx->result = result; now = isc_time_now(); fctx->duration = isc_time_microdiff(&now, &fctx->start); for (resp = ISC_LIST_HEAD(fctx->resps); resp != NULL; resp = next) { next = ISC_LIST_NEXT(resp, link); ISC_LIST_UNLINK(fctx->resps, resp, link); count++; resp->vresult = fctx->vresult; if (!HAVE_ANSWER(fctx)) { resp->result = result; } INSIST(resp->result != ISC_R_SUCCESS || dns_rdataset_isassociated(resp->rdataset) || fctx->type == dns_rdatatype_any || fctx->type == dns_rdatatype_rrsig || fctx->type == dns_rdatatype_sig); /* * Negative results must be indicated in resp->result. */ if (dns_rdataset_isassociated(resp->rdataset) && NEGATIVE(resp->rdataset)) { INSIST(resp->result == DNS_R_NCACHENXDOMAIN || resp->result == DNS_R_NCACHENXRRSET); } FCTXTRACE("post response event"); isc_async_run(resp->loop, resp->cb, resp); } UNLOCK(&fctx->lock); if (HAVE_ANSWER(fctx) && fctx->spilled && (count < fctx->res->spillatmax || fctx->res->spillatmax == 0)) { LOCK(&fctx->res->lock); if (count == fctx->res->spillat && !atomic_load_acquire(&fctx->res->exiting)) { old_spillat = fctx->res->spillat; fctx->res->spillat += 5; if (fctx->res->spillat > fctx->res->spillatmax && fctx->res->spillatmax != 0) { fctx->res->spillat = fctx->res->spillatmax; } new_spillat = fctx->res->spillat; if (new_spillat != old_spillat) { logit = true; } /* Timer not running */ if (fctx->res->spillattimer == NULL) { isc_interval_t i; isc_timer_create( isc_loop(), spillattimer_countdown, fctx->res, &fctx->res->spillattimer); isc_interval_set(&i, 20 * 60, 0); isc_timer_start(fctx->res->spillattimer, isc_timertype_ticker, &i); } } UNLOCK(&fctx->res->lock); if (logit) { isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER, ISC_LOG_NOTICE, "clients-per-query increased to %u", new_spillat); } } } static bool fctx__done(fetchctx_t *fctx, isc_result_t result, const char *func, const char *file, unsigned int line) { bool no_response = false; bool age_untried = false; REQUIRE(fctx != NULL); REQUIRE(fctx->tid == isc_tid()); FCTXTRACE("done"); #ifdef DNS_RESOLVER_TRACE fprintf(stderr, "%s:%s:%s:%u:(%p): %s\n", __func__, func, file, line, fctx, isc_result_totext(result)); #else UNUSED(file); UNUSED(line); UNUSED(func); #endif LOCK(&fctx->lock); /* We need to do this under the lock for intra-thread synchronization */ if (fctx->state == fetchstate_done) { UNLOCK(&fctx->lock); return false; } fctx->state = fetchstate_done; release_fctx(fctx); FCTX_ATTR_CLR(fctx, FCTX_ATTR_ADDRWAIT); UNLOCK(&fctx->lock); if (result == ISC_R_SUCCESS) { if (fctx->qmin_warning != ISC_R_SUCCESS) { isc_log_write(dns_lctx, DNS_LOGCATEGORY_LAME_SERVERS, DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO, "success resolving '%s' after disabling " "qname minimization due to '%s'", fctx->info, isc_result_totext(fctx->qmin_warning)); } /* * A success result indicates we got a response to a * query. That query should be canceled already. If * there still are any outstanding queries attached to the * same fctx, then those have *not* gotten a response, * so we set 'no_response' to true here: that way, when * we run fctx_cancelqueries() below, the SRTTs will * be adjusted. */ no_response = true; } else if (result == ISC_R_TIMEDOUT) { age_untried = true; } fctx->qmin_warning = ISC_R_SUCCESS; fctx_cancelqueries(fctx, no_response, age_untried); fctx_stoptimer(fctx); /* * Cancel all pending validators. Note that this must be done * without the fctx lock held, since that could cause * deadlock. */ maybe_cancel_validators(fctx); if (fctx->nsfetch != NULL) { dns_resolver_cancelfetch(fctx->nsfetch); } if (fctx->qminfetch != NULL) { dns_resolver_cancelfetch(fctx->qminfetch); } /* * Shut down anything still running on behalf of this * fetch, and clean up finds and addresses. */ fctx_sendevents(fctx, result); fctx_cleanup(fctx); isc_timer_destroy(&fctx->timer); return true; } static void resquery_senddone(isc_result_t eresult, isc_region_t *region, void *arg) { resquery_t *query = (resquery_t *)arg; resquery_t *copy = query; fetchctx_t *fctx = NULL; QTRACE("senddone"); UNUSED(region); REQUIRE(VALID_QUERY(query)); fctx = query->fctx; REQUIRE(VALID_FCTX(fctx)); REQUIRE(fctx->tid == isc_tid()); if (RESQUERY_CANCELED(query)) { goto detach; } /* * See the note in resquery_connected() about reference * counting on error conditions. */ switch (eresult) { case ISC_R_SUCCESS: case ISC_R_CANCELED: case ISC_R_SHUTTINGDOWN: break; case ISC_R_HOSTDOWN: case ISC_R_HOSTUNREACH: case ISC_R_NETDOWN: case ISC_R_NETUNREACH: case ISC_R_NOPERM: case ISC_R_ADDRNOTAVAIL: case ISC_R_CONNREFUSED: case ISC_R_CONNECTIONRESET: case ISC_R_TIMEDOUT: /* No route to remote. */ FCTXTRACE3("query canceled in resquery_senddone(): " "no route to host; no response", eresult); add_bad(fctx, query->rmessage, query->addrinfo, eresult, badns_unreachable); fctx_cancelquery(©, NULL, true, false); FCTX_ATTR_CLR(fctx, FCTX_ATTR_ADDRWAIT); fctx_try(fctx, true); break; default: FCTXTRACE3("query canceled in resquery_senddone() " "due to unexpected result; responding", eresult); fctx_cancelquery(©, NULL, false, false); fctx_done_detach(&fctx, eresult); break; } detach: resquery_detach(&query); } static isc_result_t fctx_addopt(dns_message_t *message, unsigned int version, uint16_t udpsize, dns_ednsopt_t *ednsopts, size_t count) { dns_rdataset_t *rdataset = NULL; isc_result_t result; result = dns_message_buildopt(message, &rdataset, version, udpsize, DNS_MESSAGEEXTFLAG_DO, ednsopts, count); if (result != ISC_R_SUCCESS) { return result; } return dns_message_setopt(message, rdataset); } static void fctx_setretryinterval(fetchctx_t *fctx, unsigned int rtt) { unsigned int seconds, us; uint64_t limit; isc_time_t now; /* * Has this fetch already expired? */ now = isc_time_now(); limit = isc_time_microdiff(&fctx->expires, &now); if (limit < US_PER_MS) { FCTXTRACE("fetch already expired"); isc_interval_set(&fctx->interval, 0, 0); return; } us = fctx->res->retryinterval * US_PER_MS; /* * Exponential backoff after the first few tries. */ if (fctx->restarts > fctx->res->nonbackofftries) { int shift = fctx->restarts - fctx->res->nonbackofftries; if (shift > 6) { shift = 6; } us <<= shift; } /* * Add a fudge factor to the expected rtt based on the current * estimate. */ if (rtt < 50000) { rtt += 50000; } else if (rtt < 100000) { rtt += 100000; } else { rtt += 200000; } /* * Always wait for at least the expected rtt. */ if (us < rtt) { us = rtt; } /* * But don't wait past the the final expiration of the fetch, * or for more than 10 seconds total. */ if (us > limit) { us = limit; } if (us > MAX_SINGLE_QUERY_TIMEOUT_US) { us = MAX_SINGLE_QUERY_TIMEOUT_US; } if (us > fctx->res->query_timeout * US_PER_MS) { us = fctx->res->query_timeout * US_PER_MS; } seconds = us / US_PER_SEC; us -= seconds * US_PER_SEC; isc_interval_set(&fctx->interval, seconds, us * NS_PER_US); isc_time_nowplusinterval(&fctx->next_timeout, &fctx->interval); } static isc_result_t fctx_query(fetchctx_t *fctx, dns_adbaddrinfo_t *addrinfo, unsigned int options) { isc_result_t result; dns_resolver_t *res = NULL; dns_dns64_t *dns64 = NULL; resquery_t *query = NULL; isc_sockaddr_t addr, sockaddr; bool have_addr = false; unsigned int srtt; isc_tlsctx_cache_t *tlsctx_cache = NULL; FCTXTRACE("query"); res = fctx->res; srtt = addrinfo->srtt; if (addrinfo->transport != NULL) { switch (dns_transport_get_type(addrinfo->transport)) { case DNS_TRANSPORT_TLS: options |= DNS_FETCHOPT_TCP; tlsctx_cache = res->tlsctx_cache; break; case DNS_TRANSPORT_TCP: case DNS_TRANSPORT_HTTP: options |= DNS_FETCHOPT_TCP; break; default: break; } } /* * Allow an additional second for the kernel to resend the SYN * (or SYN without ECN in the case of stupid firewalls blocking * ECN negotiation) over the current RTT estimate. */ if ((options & DNS_FETCHOPT_TCP) != 0) { srtt += US_PER_SEC; } /* * A forwarder needs to make multiple queries. Give it at least * a second to do these in. */ if (ISFORWARDER(addrinfo) && srtt < US_PER_SEC) { srtt = US_PER_SEC; } fctx_setretryinterval(fctx, srtt); if (isc_interval_iszero(&fctx->interval)) { FCTXTRACE("fetch expired"); return ISC_R_TIMEDOUT; } INSIST(ISC_LIST_EMPTY(fctx->validators)); query = isc_mem_get(fctx->mctx, sizeof(*query)); *query = (resquery_t){ .options = options, .addrinfo = addrinfo, .dispatchmgr = res->view->dispatchmgr, .link = ISC_LINK_INITIALIZER, }; #if DNS_RESOLVER_TRACE fprintf(stderr, "rctx_init:%s:%s:%d:%p->references = 1\n", __func__, __FILE__, __LINE__, query); #endif isc_refcount_init(&query->references, 1); /* * Note that the caller MUST guarantee that 'addrinfo' will * remain valid until this query is canceled. */ dns_message_create(fctx->mctx, fctx->res->namepools[fctx->tid], fctx->res->rdspools[fctx->tid], DNS_MESSAGE_INTENTPARSE, &query->rmessage); query->start = isc_time_now(); /* * Maybe apply DNS64 mappings to IPv4 addresses. */ sockaddr = addrinfo->sockaddr; dns64 = ISC_LIST_HEAD(fctx->res->view->dns64); if (isc_sockaddr_pf(&sockaddr) == AF_INET && fctx->res->view->usedns64 && dns64 != NULL) { struct in6_addr aaaa; result = dns_dns64_aaaafroma( dns64, NULL, NULL, fctx->res->view->aclenv, 0, (unsigned char *)&sockaddr.type.sin.sin_addr.s_addr, aaaa.s6_addr); if (result == ISC_R_SUCCESS) { char sockaddrbuf1[ISC_SOCKADDR_FORMATSIZE]; char sockaddrbuf2[ISC_SOCKADDR_FORMATSIZE]; /* format old address */ isc_sockaddr_format(&sockaddr, sockaddrbuf1, sizeof(sockaddrbuf1)); /* replace address */ isc_sockaddr_fromin6(&sockaddr, &aaaa, ntohs(sockaddr.type.sin.sin_port)); addrinfo->sockaddr = sockaddr; /* format new address */ isc_sockaddr_format(&sockaddr, sockaddrbuf2, sizeof(sockaddrbuf2)); isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER, ISC_LOG_DEBUG(3), "Using DNS64 address %s to talk to %s\n", sockaddrbuf2, sockaddrbuf1); } } if (res->view->peers != NULL) { dns_peer_t *peer = NULL; isc_netaddr_t dstip; bool usetcp = false; isc_netaddr_fromsockaddr(&dstip, &sockaddr); result = dns_peerlist_peerbyaddr(res->view->peers, &dstip, &peer); if (result == ISC_R_SUCCESS) { result = dns_peer_getquerysource(peer, &addr); if (result == ISC_R_SUCCESS) { have_addr = true; } result = dns_peer_getforcetcp(peer, &usetcp); if (result == ISC_R_SUCCESS && usetcp) { query->options |= DNS_FETCHOPT_TCP; } } } /* * If this is a TCP query, then we need to make a socket and * a dispatch for it here. Otherwise we use the resolver's * shared dispatch. */ if ((query->options & DNS_FETCHOPT_TCP) != 0) { int pf; pf = isc_sockaddr_pf(&sockaddr); if (!have_addr) { switch (pf) { case PF_INET: result = dns_dispatch_getlocaladdress( res->dispatches4->dispatches[0], &addr); break; case PF_INET6: result = dns_dispatch_getlocaladdress( res->dispatches6->dispatches[0], &addr); break; default: result = ISC_R_NOTIMPLEMENTED; break; } if (result != ISC_R_SUCCESS) { goto cleanup_query; } } isc_sockaddr_setport(&addr, 0); result = dns_dispatch_createtcp(res->view->dispatchmgr, &addr, &sockaddr, addrinfo->transport, DNS_DISPATCHOPT_UNSHARED, &query->dispatch); if (result != ISC_R_SUCCESS) { goto cleanup_query; } FCTXTRACE("connecting via TCP"); } else { if (have_addr) { result = dns_dispatch_createudp(res->view->dispatchmgr, &addr, &query->dispatch); if (result != ISC_R_SUCCESS) { goto cleanup_query; } } else { switch (isc_sockaddr_pf(&sockaddr)) { case PF_INET: dns_dispatch_attach( dns_resolver_dispatchv4(res), &query->dispatch); break; case PF_INET6: dns_dispatch_attach( dns_resolver_dispatchv6(res), &query->dispatch); break; default: result = ISC_R_NOTIMPLEMENTED; goto cleanup_query; } } /* * We should always have a valid dispatcher here. If we * don't support a protocol family, then its dispatcher * will be NULL, but we shouldn't be finding addresses * for protocol types we don't support, so the * dispatcher we found should never be NULL. */ INSIST(query->dispatch != NULL); } LOCK(&fctx->lock); INSIST(!SHUTTINGDOWN(fctx)); fetchctx_attach(fctx, &query->fctx); query->magic = QUERY_MAGIC; if ((query->options & DNS_FETCHOPT_TCP) == 0) { if (dns_adb_overquota(fctx->adb, addrinfo)) { UNLOCK(&fctx->lock); result = ISC_R_QUOTA; goto cleanup_dispatch; } /* Inform the ADB that we're starting a UDP fetch */ dns_adb_beginudpfetch(fctx->adb, addrinfo); } ISC_LIST_APPEND(fctx->queries, query, link); atomic_fetch_add_relaxed(&fctx->nqueries, 1); UNLOCK(&fctx->lock); /* Set up the dispatch and set the query ID */ result = dns_dispatch_add(query->dispatch, fctx->loop, 0, isc_interval_ms(&fctx->interval), &sockaddr, addrinfo->transport, tlsctx_cache, resquery_connected, resquery_senddone, resquery_response, query, &query->id, &query->dispentry); if (result != ISC_R_SUCCESS) { goto cleanup_udpfetch; } /* Connect the socket */ resquery_ref(query); result = dns_dispatch_connect(query->dispentry); if (result != ISC_R_SUCCESS && (query->options & DNS_FETCHOPT_TCP) != 0) { int log_level = ISC_LOG_NOTICE; if (isc_log_wouldlog(dns_lctx, log_level)) { char peerbuf[ISC_SOCKADDR_FORMATSIZE]; isc_sockaddr_format(&sockaddr, peerbuf, ISC_SOCKADDR_FORMATSIZE); isc_log_write( dns_lctx, DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER, log_level, "Unable to establish a connection to %s: %s\n", peerbuf, isc_result_totext(result)); } dns_dispatch_done(&query->dispentry); goto cleanup_fetch; } else { RUNTIME_CHECK(result == ISC_R_SUCCESS); } return result; cleanup_udpfetch: if (!RESQUERY_CANCELED(query)) { if ((query->options & DNS_FETCHOPT_TCP) == 0) { /* Inform the ADB that we're ending a UDP fetch */ dns_adb_endudpfetch(fctx->adb, addrinfo); } } cleanup_fetch: LOCK(&fctx->lock); if (ISC_LINK_LINKED(query, link)) { atomic_fetch_sub_release(&fctx->nqueries, 1); ISC_LIST_UNLINK(fctx->queries, query, link); } UNLOCK(&fctx->lock); cleanup_dispatch: fetchctx_detach(&query->fctx); if (query->dispatch != NULL) { dns_dispatch_detach(&query->dispatch); } cleanup_query: query->magic = 0; dns_message_detach(&query->rmessage); isc_mem_put(fctx->mctx, query, sizeof(*query)); return result; } static bool bad_edns(fetchctx_t *fctx, isc_sockaddr_t *address) { isc_sockaddr_t *sa; for (sa = ISC_LIST_HEAD(fctx->bad_edns); sa != NULL; sa = ISC_LIST_NEXT(sa, link)) { if (isc_sockaddr_equal(sa, address)) { return true; } } return false; } static void add_bad_edns(fetchctx_t *fctx, isc_sockaddr_t *address) { isc_sockaddr_t *sa; #ifdef ENABLE_AFL if (dns_fuzzing_resolver) { return; } #endif /* ifdef ENABLE_AFL */ if (bad_edns(fctx, address)) { return; } sa = isc_mem_get(fctx->mctx, sizeof(*sa)); *sa = *address; ISC_LIST_INITANDAPPEND(fctx->bad_edns, sa, link); } static struct tried * triededns(fetchctx_t *fctx, isc_sockaddr_t *address) { struct tried *tried; for (tried = ISC_LIST_HEAD(fctx->edns); tried != NULL; tried = ISC_LIST_NEXT(tried, link)) { if (isc_sockaddr_equal(&tried->addr, address)) { return tried; } } return NULL; } static void add_triededns(fetchctx_t *fctx, isc_sockaddr_t *address) { struct tried *tried; tried = triededns(fctx, address); if (tried != NULL) { tried->count++; return; } tried = isc_mem_get(fctx->mctx, sizeof(*tried)); tried->addr = *address; tried->count = 1; ISC_LIST_INITANDAPPEND(fctx->edns, tried, link); } static size_t addr2buf(void *buf, const size_t bufsize, const isc_sockaddr_t *sockaddr) { isc_netaddr_t netaddr; isc_netaddr_fromsockaddr(&netaddr, sockaddr); switch (netaddr.family) { case AF_INET: INSIST(bufsize >= 4); memmove(buf, &netaddr.type.in, 4); return 4; case AF_INET6: INSIST(bufsize >= 16); memmove(buf, &netaddr.type.in6, 16); return 16; default: UNREACHABLE(); } return 0; } static size_t add_serveraddr(uint8_t *buf, const size_t bufsize, const resquery_t *query) { return addr2buf(buf, bufsize, &query->addrinfo->sockaddr); } /* * Client cookie is 8 octets. * Server cookie is [8..32] octets. */ #define CLIENT_COOKIE_SIZE 8U #define COOKIE_BUFFER_SIZE (8U + 32U) static void compute_cc(const resquery_t *query, uint8_t *cookie, const size_t len) { INSIST(len >= CLIENT_COOKIE_SIZE); STATIC_ASSERT(sizeof(query->fctx->res->view->secret) >= ISC_SIPHASH24_KEY_LENGTH, "The view->secret size can't fit SipHash 2-4 key " "length"); uint8_t buf[16] ISC_NONSTRING = { 0 }; size_t buflen = add_serveraddr(buf, sizeof(buf), query); uint8_t digest[ISC_SIPHASH24_TAG_LENGTH] ISC_NONSTRING = { 0 }; isc_siphash24(query->fctx->res->view->secret, buf, buflen, true, digest); memmove(cookie, digest, CLIENT_COOKIE_SIZE); } static isc_result_t issecuredomain(dns_view_t *view, const dns_name_t *name, dns_rdatatype_t type, isc_stdtime_t now, bool checknta, bool *ntap, bool *issecure) { dns_name_t suffix; unsigned int labels; /* * For DS variants we need to check fom the parent domain, * since there may be a negative trust anchor for the name, * while the enclosing domain where the DS record lives is * under a secure entry point. */ labels = dns_name_countlabels(name); if (dns_rdatatype_atparent(type) && labels > 1) { dns_name_init(&suffix, NULL); dns_name_getlabelsequence(name, 1, labels - 1, &suffix); name = &suffix; } return dns_view_issecuredomain(view, name, now, checknta, ntap, issecure); } static isc_result_t resquery_send(resquery_t *query) { isc_result_t result; fetchctx_t *fctx = query->fctx; dns_resolver_t *res = fctx->res; isc_buffer_t buffer; dns_name_t *qname = NULL; dns_rdataset_t *qrdataset = NULL; isc_region_t r; isc_netaddr_t ipaddr; dns_tsigkey_t *tsigkey = NULL; dns_peer_t *peer = NULL; dns_compress_t cctx; bool useedns; bool secure_domain; bool tcp = ((query->options & DNS_FETCHOPT_TCP) != 0); dns_ednsopt_t ednsopts[DNS_EDNSOPTIONS]; unsigned int ednsopt = 0; uint16_t hint = 0, udpsize = 0; /* No EDNS */ #ifdef HAVE_DNSTAP isc_sockaddr_t localaddr, *la = NULL; unsigned char zone[DNS_NAME_MAXWIRE]; dns_transport_type_t transport_type; dns_dtmsgtype_t dtmsgtype; isc_region_t zr; isc_buffer_t zb; #endif /* HAVE_DNSTAP */ QTRACE("send"); if (atomic_load_acquire(&res->exiting)) { FCTXTRACE("resquery_send: resolver shutting down"); return ISC_R_SHUTTINGDOWN; } dns_message_gettempname(fctx->qmessage, &qname); dns_message_gettemprdataset(fctx->qmessage, &qrdataset); fctx->qmessage->opcode = dns_opcode_query; /* * Set up question. */ dns_name_clone(fctx->name, qname); dns_rdataset_makequestion(qrdataset, res->rdclass, fctx->type); ISC_LIST_APPEND(qname->list, qrdataset, link); dns_message_addname(fctx->qmessage, qname, DNS_SECTION_QUESTION); /* * Set RD if the client has requested that we do a recursive * query, or if we're sending to a forwarder. */ if ((query->options & DNS_FETCHOPT_RECURSIVE) != 0 || ISFORWARDER(query->addrinfo)) { fctx->qmessage->flags |= DNS_MESSAGEFLAG_RD; } /* * Set CD if the client says not to validate, or if the * question is under a secure entry point and this is a * recursive/forward query -- unless the client said not to. */ if ((query->options & DNS_FETCHOPT_NOCDFLAG) != 0) { /* Do nothing */ } else if ((query->options & DNS_FETCHOPT_NOVALIDATE) != 0) { fctx->qmessage->flags |= DNS_MESSAGEFLAG_CD; } else if (res->view->enablevalidation && ((fctx->qmessage->flags & DNS_MESSAGEFLAG_RD) != 0)) { bool checknta = ((query->options & DNS_FETCHOPT_NONTA) == 0); bool ntacovered = false; result = issecuredomain(res->view, fctx->name, fctx->type, isc_time_seconds(&query->start), checknta, &ntacovered, &secure_domain); if (result != ISC_R_SUCCESS) { secure_domain = false; } if (secure_domain || (ISFORWARDER(query->addrinfo) && ntacovered)) { fctx->qmessage->flags |= DNS_MESSAGEFLAG_CD; } } /* * We don't have to set opcode because it defaults to query. */ fctx->qmessage->id = query->id; /* * Convert the question to wire format. */ dns_compress_init(&cctx, fctx->mctx, 0); isc_buffer_init(&buffer, query->data, sizeof(query->data)); result = dns_message_renderbegin(fctx->qmessage, &cctx, &buffer); if (result != ISC_R_SUCCESS) { goto cleanup_message; } result = dns_message_rendersection(fctx->qmessage, DNS_SECTION_QUESTION, 0); if (result != ISC_R_SUCCESS) { goto cleanup_message; } isc_netaddr_fromsockaddr(&ipaddr, &query->addrinfo->sockaddr); (void)dns_peerlist_peerbyaddr(fctx->res->view->peers, &ipaddr, &peer); /* * The ADB does not know about servers with "edns no". Check * this, and then inform the ADB for future use. */ if ((query->addrinfo->flags & FCTX_ADDRINFO_NOEDNS0) == 0 && peer != NULL && dns_peer_getsupportedns(peer, &useedns) == ISC_R_SUCCESS && !useedns) { query->options |= DNS_FETCHOPT_NOEDNS0; dns_adb_changeflags(fctx->adb, query->addrinfo, FCTX_ADDRINFO_NOEDNS0, FCTX_ADDRINFO_NOEDNS0); } /* Sync NOEDNS0 flag in addrinfo->flags and options now. */ if ((query->addrinfo->flags & FCTX_ADDRINFO_NOEDNS0) != 0) { query->options |= DNS_FETCHOPT_NOEDNS0; } if (fctx->timeout && (query->options & DNS_FETCHOPT_NOEDNS0) == 0) { isc_sockaddr_t *sockaddr = &query->addrinfo->sockaddr; struct tried *tried; /* * If this is the first timeout for this server in this * fetch context, try setting EDNS UDP buffer size to * the largest UDP response size we have seen from this * server so far. * * If this server has already timed out twice or more in * this fetch context, force TCP. */ if ((tried = triededns(fctx, sockaddr)) != NULL) { if (tried->count == 1U) { hint = dns_adb_getudpsize(fctx->adb, query->addrinfo); } else if (tried->count >= 2U) { if ((query->options & DNS_FETCHOPT_TCP) == 0) { /* * Inform the ADB that we're ending a * UDP fetch, and turn the query into * a TCP query. */ dns_adb_endudpfetch(fctx->adb, query->addrinfo); query->options |= DNS_FETCHOPT_TCP; } } } } fctx->timeout = false; /* * Use EDNS0, unless the caller doesn't want it, or we know that * the remote server doesn't like it. */ if ((query->options & DNS_FETCHOPT_NOEDNS0) == 0) { if ((query->addrinfo->flags & FCTX_ADDRINFO_NOEDNS0) == 0) { uint16_t peerudpsize = 0; unsigned int version = DNS_EDNS_VERSION; unsigned int flags = query->addrinfo->flags; bool reqnsid = res->view->requestnsid; bool sendcookie = res->view->sendcookie; bool tcpkeepalive = false; unsigned char cookie[COOKIE_BUFFER_SIZE]; uint16_t padding = 0; /* * Set the default UDP size to what was * configured as 'edns-buffer-size' */ udpsize = res->view->udpsize; /* * This server timed out for the first time in * this fetch context and we received a response * from it before (either in this fetch context * or in a different one). Set 'udpsize' to the * size of the largest UDP response we have * received from this server so far. */ if (hint != 0U) { udpsize = hint; } /* * If a fixed EDNS UDP buffer size is configured * for this server, make sure we obey that. */ if (peer != NULL) { (void)dns_peer_getudpsize(peer, &peerudpsize); if (peerudpsize != 0) { udpsize = peerudpsize; } } if ((flags & DNS_FETCHOPT_EDNSVERSIONSET) != 0) { version = flags & DNS_FETCHOPT_EDNSVERSIONMASK; version >>= DNS_FETCHOPT_EDNSVERSIONSHIFT; } /* Request NSID/COOKIE/VERSION for current peer? */ if (peer != NULL) { uint8_t ednsversion; (void)dns_peer_getrequestnsid(peer, &reqnsid); (void)dns_peer_getsendcookie(peer, &sendcookie); result = dns_peer_getednsversion(peer, &ednsversion); if (result == ISC_R_SUCCESS && ednsversion < version) { version = ednsversion; } } if (NOCOOKIE(query->addrinfo)) { sendcookie = false; } if (reqnsid) { INSIST(ednsopt < DNS_EDNSOPTIONS); ednsopts[ednsopt].code = DNS_OPT_NSID; ednsopts[ednsopt].length = 0; ednsopts[ednsopt].value = NULL; ednsopt++; } if (sendcookie) { INSIST(ednsopt < DNS_EDNSOPTIONS); ednsopts[ednsopt].code = DNS_OPT_COOKIE; ednsopts[ednsopt].length = (uint16_t)dns_adb_getcookie( query->addrinfo, cookie, sizeof(cookie)); if (ednsopts[ednsopt].length != 0) { ednsopts[ednsopt].value = cookie; inc_stats( fctx->res, dns_resstatscounter_cookieout); } else { compute_cc(query, cookie, CLIENT_COOKIE_SIZE); ednsopts[ednsopt].value = cookie; ednsopts[ednsopt].length = CLIENT_COOKIE_SIZE; inc_stats( fctx->res, dns_resstatscounter_cookienew); } ednsopt++; } /* Add TCP keepalive option if appropriate */ if ((peer != NULL) && tcp) { (void)dns_peer_gettcpkeepalive(peer, &tcpkeepalive); } if (tcpkeepalive) { INSIST(ednsopt < DNS_EDNSOPTIONS); ednsopts[ednsopt].code = DNS_OPT_TCP_KEEPALIVE; ednsopts[ednsopt].length = 0; ednsopts[ednsopt].value = NULL; ednsopt++; } /* Add PAD for current peer? Require TCP for now */ if ((peer != NULL) && tcp) { (void)dns_peer_getpadding(peer, &padding); } if (padding != 0) { INSIST(ednsopt < DNS_EDNSOPTIONS); ednsopts[ednsopt].code = DNS_OPT_PAD; ednsopts[ednsopt].length = 0; ednsopt++; dns_message_setpadding(fctx->qmessage, padding); } query->ednsversion = version; result = fctx_addopt(fctx->qmessage, version, udpsize, ednsopts, ednsopt); if (reqnsid && result == ISC_R_SUCCESS) { query->options |= DNS_FETCHOPT_WANTNSID; } else if (result != ISC_R_SUCCESS) { /* * We couldn't add the OPT, but we'll * press on. We're not using EDNS0, so * set the NOEDNS0 bit. */ query->options |= DNS_FETCHOPT_NOEDNS0; query->ednsversion = -1; udpsize = 0; } } else { /* * We know this server doesn't like EDNS0, so we * won't use it. Set the NOEDNS0 bit since * we're not using EDNS0. */ query->options |= DNS_FETCHOPT_NOEDNS0; query->ednsversion = -1; } } else { query->ednsversion = -1; } /* * Record the UDP EDNS size chosen. */ query->udpsize = udpsize; /* * If we need EDNS0 to do this query and aren't using it, we * lose. */ if (NEEDEDNS0(fctx) && (query->options & DNS_FETCHOPT_NOEDNS0) != 0) { result = DNS_R_SERVFAIL; goto cleanup_message; } add_triededns(fctx, &query->addrinfo->sockaddr); /* * Clear CD if EDNS is not in use. */ if ((query->options & DNS_FETCHOPT_NOEDNS0) != 0) { fctx->qmessage->flags &= ~DNS_MESSAGEFLAG_CD; } /* * Add TSIG record tailored to the current recipient. */ result = dns_view_getpeertsig(fctx->res->view, &ipaddr, &tsigkey); if (result != ISC_R_SUCCESS && result != ISC_R_NOTFOUND) { goto cleanup_message; } if (tsigkey != NULL) { result = dns_message_settsigkey(fctx->qmessage, tsigkey); dns_tsigkey_detach(&tsigkey); if (result != ISC_R_SUCCESS) { goto cleanup_message; } } result = dns_message_rendersection(fctx->qmessage, DNS_SECTION_ADDITIONAL, 0); if (result != ISC_R_SUCCESS) { goto cleanup_message; } result = dns_message_renderend(fctx->qmessage); if (result != ISC_R_SUCCESS) { goto cleanup_message; } #ifdef HAVE_DNSTAP memset(&zr, 0, sizeof(zr)); isc_buffer_init(&zb, zone, sizeof(zone)); dns_compress_setpermitted(&cctx, false); result = dns_name_towire(fctx->domain, &cctx, &zb, NULL); if (result == ISC_R_SUCCESS) { isc_buffer_usedregion(&zb, &zr); } #endif /* HAVE_DNSTAP */ if (dns_message_gettsigkey(fctx->qmessage) != NULL) { dns_tsigkey_attach(dns_message_gettsigkey(fctx->qmessage), &query->tsigkey); result = dns_message_getquerytsig(fctx->qmessage, fctx->mctx, &query->tsig); if (result != ISC_R_SUCCESS) { goto cleanup_message; } } /* * Log the outgoing packet. */ dns_message_logfmtpacket( fctx->qmessage, "sending packet to", &query->addrinfo->sockaddr, DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_PACKETS, &dns_master_style_comment, ISC_LOG_DEBUG(11), fctx->mctx); /* * We're now done with the query message. */ dns_compress_invalidate(&cctx); dns_message_reset(fctx->qmessage, DNS_MESSAGE_INTENTRENDER); isc_buffer_usedregion(&buffer, &r); resquery_ref(query); dns_dispatch_send(query->dispentry, &r); QTRACE("sent"); #ifdef HAVE_DNSTAP /* * Log the outgoing query via dnstap. */ if ((fctx->qmessage->flags & DNS_MESSAGEFLAG_RD) != 0) { dtmsgtype = DNS_DTTYPE_FQ; } else { dtmsgtype = DNS_DTTYPE_RQ; } result = dns_dispentry_getlocaladdress(query->dispentry, &localaddr); if (result == ISC_R_SUCCESS) { la = &localaddr; } if (query->addrinfo->transport != NULL) { transport_type = dns_transport_get_type(query->addrinfo->transport); } else if ((query->options & DNS_FETCHOPT_TCP) != 0) { transport_type = DNS_TRANSPORT_TCP; } else { transport_type = DNS_TRANSPORT_UDP; } dns_dt_send(fctx->res->view, dtmsgtype, la, &query->addrinfo->sockaddr, transport_type, &zr, &query->start, NULL, &buffer); #endif /* HAVE_DNSTAP */ return ISC_R_SUCCESS; cleanup_message: dns_compress_invalidate(&cctx); dns_message_reset(fctx->qmessage, DNS_MESSAGE_INTENTRENDER); /* * Stop the dispatcher from listening. */ dns_dispatch_done(&query->dispentry); return result; } static void resquery_connected(isc_result_t eresult, isc_region_t *region, void *arg) { resquery_t *query = (resquery_t *)arg; resquery_t *copy = query; isc_result_t result; fetchctx_t *fctx = NULL; dns_resolver_t *res = NULL; int pf; REQUIRE(VALID_QUERY(query)); QTRACE("connected"); UNUSED(region); fctx = query->fctx; REQUIRE(VALID_FCTX(fctx)); REQUIRE(fctx->tid == isc_tid()); res = fctx->res; if (RESQUERY_CANCELED(query)) { goto detach; } if (atomic_load_acquire(&fctx->res->exiting)) { eresult = ISC_R_SHUTTINGDOWN; } /* * The reference counting of resquery objects is complex: * * 1. attached in fctx_query() * 2. attached prior to dns_dispatch_connect(), detached in * resquery_connected() * 3. attached prior to dns_dispatch_send(), detached in * resquery_senddone() * 4. finally detached in fctx_cancelquery() * * On error conditions, it's necessary to call fctx_cancelquery() * from resquery_connected() or _senddone(), detaching twice * within the same function. To make it clear that's what's * happening, we cancel-and-detach 'copy' and detach 'query', * which are both pointing to the same object. */ switch (eresult) { case ISC_R_SUCCESS: /* * We are connected. Send the query. */ result = resquery_send(query); if (result != ISC_R_SUCCESS) { FCTXTRACE("query canceled: resquery_send() failed; " "responding"); fctx_cancelquery(©, NULL, false, false); fctx_done_detach(&fctx, result); break; } fctx->querysent++; pf = isc_sockaddr_pf(&query->addrinfo->sockaddr); if (pf == PF_INET) { inc_stats(res, dns_resstatscounter_queryv4); } else { inc_stats(res, dns_resstatscounter_queryv6); } if (res->querystats != NULL) { dns_rdatatypestats_increment(res->querystats, fctx->type); } break; case ISC_R_CANCELED: case ISC_R_SHUTTINGDOWN: FCTXTRACE3("shutdown in resquery_connected()", eresult); fctx_cancelquery(©, NULL, true, false); fctx_done_detach(&fctx, eresult); break; case ISC_R_HOSTDOWN: case ISC_R_HOSTUNREACH: case ISC_R_NETDOWN: case ISC_R_NETUNREACH: case ISC_R_CONNREFUSED: case ISC_R_NOPERM: case ISC_R_ADDRNOTAVAIL: case ISC_R_CONNECTIONRESET: case ISC_R_TIMEDOUT: /* * Do not query this server again in this fetch context. */ FCTXTRACE3("query failed in resquery_connected(): " "no response", eresult); add_bad(fctx, query->rmessage, query->addrinfo, eresult, badns_unreachable); fctx_cancelquery(©, NULL, true, false); FCTX_ATTR_CLR(fctx, FCTX_ATTR_ADDRWAIT); fctx_try(fctx, true); break; default: FCTXTRACE3("query canceled in resquery_connected() " "due to unexpected result; responding", eresult); fctx_cancelquery(©, NULL, false, false); fctx_done_detach(&fctx, eresult); break; } detach: resquery_detach(&query); } static void fctx_finddone(void *arg) { dns_adbfind_t *find = (dns_adbfind_t *)arg; fetchctx_t *fctx = (fetchctx_t *)find->cbarg; bool want_try = false; bool want_done = false; uint_fast32_t pending; REQUIRE(VALID_FCTX(fctx)); FCTXTRACE("finddone"); REQUIRE(fctx->tid == isc_tid()); LOCK(&fctx->lock); pending = atomic_fetch_sub_release(&fctx->pending, 1); INSIST(pending > 0); if (ADDRWAIT(fctx)) { /* * The fetch is waiting for a name to be found. */ INSIST(!SHUTTINGDOWN(fctx)); if (dns_adb_findstatus(find) == DNS_ADB_MOREADDRESSES) { FCTX_ATTR_CLR(fctx, FCTX_ATTR_ADDRWAIT); want_try = true; } else { fctx->findfail++; if (atomic_load_acquire(&fctx->pending) == 0) { /* * We've got nothing else to wait for * and don't know the answer. There's * nothing to do but fail the fctx. */ FCTX_ATTR_CLR(fctx, FCTX_ATTR_ADDRWAIT); want_done = true; } } } UNLOCK(&fctx->lock); dns_adb_destroyfind(&find); if (want_done) { FCTXTRACE("fetch failed in finddone(); return " "ISC_R_FAILURE"); fctx_done_unref(fctx, ISC_R_FAILURE); } else if (want_try) { fctx_try(fctx, true); } fetchctx_detach(&fctx); } static bool bad_server(fetchctx_t *fctx, isc_sockaddr_t *address) { isc_sockaddr_t *sa; for (sa = ISC_LIST_HEAD(fctx->bad); sa != NULL; sa = ISC_LIST_NEXT(sa, link)) { if (isc_sockaddr_equal(sa, address)) { return true; } } return false; } static bool mark_bad(fetchctx_t *fctx) { dns_adbfind_t *curr; dns_adbaddrinfo_t *addrinfo; bool all_bad = true; #ifdef ENABLE_AFL if (dns_fuzzing_resolver) { return false; } #endif /* ifdef ENABLE_AFL */ /* * Mark all known bad servers, so we don't try to talk to them * again. */ /* * Mark any bad nameservers. */ for (curr = ISC_LIST_HEAD(fctx->finds); curr != NULL; curr = ISC_LIST_NEXT(curr, publink)) { for (addrinfo = ISC_LIST_HEAD(curr->list); addrinfo != NULL; addrinfo = ISC_LIST_NEXT(addrinfo, publink)) { if (bad_server(fctx, &addrinfo->sockaddr)) { addrinfo->flags |= FCTX_ADDRINFO_MARK; } else { all_bad = false; } } } /* * Mark any bad forwarders. */ for (addrinfo = ISC_LIST_HEAD(fctx->forwaddrs); addrinfo != NULL; addrinfo = ISC_LIST_NEXT(addrinfo, publink)) { if (bad_server(fctx, &addrinfo->sockaddr)) { addrinfo->flags |= FCTX_ADDRINFO_MARK; } else { all_bad = false; } } /* * Mark any bad alternates. */ for (curr = ISC_LIST_HEAD(fctx->altfinds); curr != NULL; curr = ISC_LIST_NEXT(curr, publink)) { for (addrinfo = ISC_LIST_HEAD(curr->list); addrinfo != NULL; addrinfo = ISC_LIST_NEXT(addrinfo, publink)) { if (bad_server(fctx, &addrinfo->sockaddr)) { addrinfo->flags |= FCTX_ADDRINFO_MARK; } else { all_bad = false; } } } for (addrinfo = ISC_LIST_HEAD(fctx->altaddrs); addrinfo != NULL; addrinfo = ISC_LIST_NEXT(addrinfo, publink)) { if (bad_server(fctx, &addrinfo->sockaddr)) { addrinfo->flags |= FCTX_ADDRINFO_MARK; } else { all_bad = false; } } return all_bad; } static void add_bad(fetchctx_t *fctx, dns_message_t *rmessage, dns_adbaddrinfo_t *addrinfo, isc_result_t reason, badnstype_t badtype) { char namebuf[DNS_NAME_FORMATSIZE]; char addrbuf[ISC_SOCKADDR_FORMATSIZE]; char classbuf[64]; char typebuf[64]; char code[64]; isc_buffer_t b; isc_sockaddr_t *sa; const char *spc = ""; isc_sockaddr_t *address = &addrinfo->sockaddr; #ifdef ENABLE_AFL if (dns_fuzzing_resolver) { return; } #endif /* ifdef ENABLE_AFL */ if (reason == DNS_R_LAME) { fctx->lamecount++; } else { switch (badtype) { case badns_unreachable: fctx->neterr++; break; case badns_response: fctx->badresp++; break; case badns_validation: break; /* counted as 'valfail' */ case badns_forwarder: /* * We were called to prevent the given forwarder * from being used again for this fetch context. */ break; } } if (bad_server(fctx, address)) { /* * We already know this server is bad. */ return; } FCTXTRACE("add_bad"); sa = isc_mem_get(fctx->mctx, sizeof(*sa)); *sa = *address; ISC_LIST_INITANDAPPEND(fctx->bad, sa, link); if (reason == DNS_R_LAME) { /* already logged */ return; } if (reason == DNS_R_UNEXPECTEDRCODE && rmessage->rcode == dns_rcode_servfail && ISFORWARDER(addrinfo)) { return; } if (reason == DNS_R_UNEXPECTEDRCODE) { isc_buffer_init(&b, code, sizeof(code) - 1); dns_rcode_totext(rmessage->rcode, &b); code[isc_buffer_usedlength(&b)] = '\0'; spc = " "; } else if (reason == DNS_R_UNEXPECTEDOPCODE) { isc_buffer_init(&b, code, sizeof(code) - 1); dns_opcode_totext((dns_opcode_t)rmessage->opcode, &b); code[isc_buffer_usedlength(&b)] = '\0'; spc = " "; } else { code[0] = '\0'; } dns_name_format(fctx->name, namebuf, sizeof(namebuf)); dns_rdatatype_format(fctx->type, typebuf, sizeof(typebuf)); dns_rdataclass_format(fctx->res->rdclass, classbuf, sizeof(classbuf)); isc_sockaddr_format(address, addrbuf, sizeof(addrbuf)); isc_log_write( dns_lctx, DNS_LOGCATEGORY_LAME_SERVERS, DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO, "%s%s%s resolving '%s/%s/%s': %s", code, spc, isc_result_totext(reason), namebuf, typebuf, classbuf, addrbuf); } /* * Sort addrinfo list by RTT. */ static void sort_adbfind(dns_adbfind_t *find, unsigned int bias) { dns_adbaddrinfo_t *best, *curr; dns_adbaddrinfolist_t sorted; /* Lame N^2 bubble sort. */ ISC_LIST_INIT(sorted); while (!ISC_LIST_EMPTY(find->list)) { unsigned int best_srtt; best = ISC_LIST_HEAD(find->list); best_srtt = best->srtt; if (isc_sockaddr_pf(&best->sockaddr) != AF_INET6) { best_srtt += bias; } curr = ISC_LIST_NEXT(best, publink); while (curr != NULL) { unsigned int curr_srtt = curr->srtt; if (isc_sockaddr_pf(&curr->sockaddr) != AF_INET6) { curr_srtt += bias; } if (curr_srtt < best_srtt) { best = curr; best_srtt = curr_srtt; } curr = ISC_LIST_NEXT(curr, publink); } ISC_LIST_UNLINK(find->list, best, publink); ISC_LIST_APPEND(sorted, best, publink); } find->list = sorted; } /* * Sort a list of finds by server RTT. */ static void sort_finds(dns_adbfindlist_t *findlist, unsigned int bias) { dns_adbfind_t *best, *curr; dns_adbfindlist_t sorted; dns_adbaddrinfo_t *addrinfo, *bestaddrinfo; /* Sort each find's addrinfo list by SRTT. */ for (curr = ISC_LIST_HEAD(*findlist); curr != NULL; curr = ISC_LIST_NEXT(curr, publink)) { sort_adbfind(curr, bias); } /* Lame N^2 bubble sort. */ ISC_LIST_INIT(sorted); while (!ISC_LIST_EMPTY(*findlist)) { unsigned int best_srtt; best = ISC_LIST_HEAD(*findlist); bestaddrinfo = ISC_LIST_HEAD(best->list); INSIST(bestaddrinfo != NULL); best_srtt = bestaddrinfo->srtt; if (isc_sockaddr_pf(&bestaddrinfo->sockaddr) != AF_INET6) { best_srtt += bias; } curr = ISC_LIST_NEXT(best, publink); while (curr != NULL) { unsigned int curr_srtt; addrinfo = ISC_LIST_HEAD(curr->list); INSIST(addrinfo != NULL); curr_srtt = addrinfo->srtt; if (isc_sockaddr_pf(&addrinfo->sockaddr) != AF_INET6) { curr_srtt += bias; } if (curr_srtt < best_srtt) { best = curr; best_srtt = curr_srtt; } curr = ISC_LIST_NEXT(curr, publink); } ISC_LIST_UNLINK(*findlist, best, publink); ISC_LIST_APPEND(sorted, best, publink); } *findlist = sorted; } /* * Return true iff the ADB find has a pending fetch for 'type'. This is * used to find out whether we're in a loop, where a fetch is waiting for a * find which is waiting for that same fetch. * * Note: This could be done with either an equivalence check (e.g., * query_pending == DNS_ADBFIND_INET) or with a bit check, as below. If * we checked for equivalence, that would mean we could only detect a loop * when there is exactly one pending fetch, and we're it. If there were * pending fetches for *both* address families, then a loop would be * undetected. * * However, using a bit check means that in theory, an ADB find might be * aborted that could have succeeded, if the other fetch had returned an * answer. * * Since there's a good chance the server is broken and won't answer either * query, and since an ADB find with two pending fetches is a very rare * occurrance anyway, we regard this theoretical SERVFAIL as the lesser * evil. */ static bool waiting_for(dns_adbfind_t *find, dns_rdatatype_t type) { switch (type) { case dns_rdatatype_a: return (find->query_pending & DNS_ADBFIND_INET) != 0; case dns_rdatatype_aaaa: return (find->query_pending & DNS_ADBFIND_INET6) != 0; default: return false; } } static void findname(fetchctx_t *fctx, const dns_name_t *name, in_port_t port, unsigned int options, unsigned int flags, isc_stdtime_t now, bool *overquota, bool *need_alternate, unsigned int *no_addresses) { dns_adbaddrinfo_t *ai = NULL; dns_adbfind_t *find = NULL; dns_resolver_t *res = fctx->res; bool unshared = ((fctx->options & DNS_FETCHOPT_UNSHARED) != 0); isc_result_t result; FCTXTRACE("FINDNAME"); /* * If this name is a subdomain of the query domain, tell * the ADB to start looking using zone/hint data. This keeps us * from getting stuck if the nameserver is beneath the zone cut * and we don't know its address (e.g. because the A record has * expired). */ if (dns_name_issubdomain(name, fctx->domain)) { options |= DNS_ADBFIND_STARTATZONE; } /* * Exempt prefetches from ADB quota. */ if ((fctx->options & DNS_FETCHOPT_PREFETCH) != 0) { options |= DNS_ADBFIND_QUOTAEXEMPT; } /* * See what we know about this address. */ INSIST(!SHUTTINGDOWN(fctx)); fetchctx_ref(fctx); result = dns_adb_createfind(fctx->adb, fctx->loop, fctx_finddone, fctx, name, fctx->name, fctx->type, options, now, NULL, res->view->dstport, fctx->depth + 1, fctx->qc, &find); isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER, ISC_LOG_DEBUG(3), "fctx %p(%s): createfind for %s - %s", fctx, fctx->info, fctx->clientstr, isc_result_totext(result)); if (result != ISC_R_SUCCESS) { if (result == DNS_R_ALIAS) { char namebuf[DNS_NAME_FORMATSIZE]; /* * XXXRTH Follow the CNAME/DNAME chain? */ dns_adb_destroyfind(&find); fctx->adberr++; dns_name_format(name, namebuf, sizeof(namebuf)); isc_log_write(dns_lctx, DNS_LOGCATEGORY_CNAME, DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO, "skipping nameserver '%s' because it " "is a CNAME, while resolving '%s'", namebuf, fctx->info); } fetchctx_detach(&fctx); return; } if (!ISC_LIST_EMPTY(find->list)) { /* * We have at least some of the addresses for the * name. */ INSIST((find->options & DNS_ADBFIND_WANTEVENT) == 0); if (flags != 0 || port != 0) { for (ai = ISC_LIST_HEAD(find->list); ai != NULL; ai = ISC_LIST_NEXT(ai, publink)) { ai->flags |= flags; if (port != 0) { isc_sockaddr_setport(&ai->sockaddr, port); } } } if ((flags & FCTX_ADDRINFO_DUALSTACK) != 0) { ISC_LIST_APPEND(fctx->altfinds, find, publink); } else { ISC_LIST_APPEND(fctx->finds, find, publink); } return; } /* * We don't know any of the addresses for this name. * * The find may be waiting on a resolver fetch for a server * address. We need to make sure it isn't waiting on *this* * fetch, because if it is, we won't be answering it and it * won't be answering us. */ if (waiting_for(find, fctx->type) && dns_name_equal(name, fctx->name)) { fctx->adberr++; isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO, "loop detected resolving '%s'", fctx->info); if ((find->options & DNS_ADBFIND_WANTEVENT) != 0) { atomic_fetch_add_relaxed(&fctx->pending, 1); dns_adb_cancelfind(find); } else { dns_adb_destroyfind(&find); fetchctx_detach(&fctx); } return; } /* * We may be waiting for another fetch to complete, and * we'll get an event later when the find has what it needs. */ if ((find->options & DNS_ADBFIND_WANTEVENT) != 0) { atomic_fetch_add_relaxed(&fctx->pending, 1); /* * Bootstrap. */ if (need_alternate != NULL && !*need_alternate && unshared && ((res->dispatches4 == NULL && find->result_v6 != DNS_R_NXDOMAIN) || (res->dispatches6 == NULL && find->result_v4 != DNS_R_NXDOMAIN))) { *need_alternate = true; } if (no_addresses != NULL) { (*no_addresses)++; } return; } /* * No addresses and no pending events: the find failed. */ if ((find->options & DNS_ADBFIND_OVERQUOTA) != 0) { if (overquota != NULL) { *overquota = true; } fctx->quotacount++; /* quota exceeded */ } else { fctx->adberr++; /* unreachable server, etc. */ } /* * If we know there are no addresses for the family we are using then * try to add an alternative server. */ if (need_alternate != NULL && !*need_alternate && ((res->dispatches4 == NULL && find->result_v6 == DNS_R_NXRRSET) || (res->dispatches6 == NULL && find->result_v4 == DNS_R_NXRRSET))) { *need_alternate = true; } dns_adb_destroyfind(&find); fetchctx_detach(&fctx); } static bool isstrictsubdomain(const dns_name_t *name1, const dns_name_t *name2) { int order; unsigned int nlabels; dns_namereln_t namereln; namereln = dns_name_fullcompare(name1, name2, &order, &nlabels); return namereln == dns_namereln_subdomain; } static isc_result_t fctx_getaddresses(fetchctx_t *fctx) { dns_rdata_t rdata = DNS_RDATA_INIT; isc_result_t result; dns_resolver_t *res; isc_stdtime_t now; unsigned int stdoptions = 0; dns_forwarder_t *fwd; dns_adbaddrinfo_t *ai; bool all_bad; dns_rdata_ns_t ns; bool need_alternate = false; bool all_spilled = false; unsigned int no_addresses = 0; unsigned int ns_processed = 0; FCTXTRACE5("getaddresses", "fctx->depth=", fctx->depth); /* * Don't pound on remote servers. (Failsafe!) */ fctx->restarts++; if (fctx->restarts > 100) { FCTXTRACE("too many restarts"); return DNS_R_SERVFAIL; } res = fctx->res; if (fctx->depth > res->maxdepth) { isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER, ISC_LOG_DEBUG(3), "too much NS indirection resolving '%s' " "(depth=%u, maxdepth=%u)", fctx->info, fctx->depth, res->maxdepth); return DNS_R_SERVFAIL; } /* * Forwarders. */ INSIST(ISC_LIST_EMPTY(fctx->forwaddrs)); INSIST(ISC_LIST_EMPTY(fctx->altaddrs)); /* * If we have DNS_FETCHOPT_NOFORWARD set and forwarding policy * allows us to not forward - skip forwarders and go straight * to NSes. This is currently used to make sure that priming * query gets root servers' IP addresses in ADDITIONAL section. */ if ((fctx->options & DNS_FETCHOPT_NOFORWARD) != 0 && (fctx->fwdpolicy != dns_fwdpolicy_only)) { goto normal_nses; } /* * If this fctx has forwarders, use them; otherwise use any * selective forwarders specified in the view; otherwise use the * resolver's forwarders (if any). */ fwd = ISC_LIST_HEAD(fctx->forwarders); if (fwd == NULL) { dns_forwarders_t *forwarders = NULL; dns_name_t *name = fctx->name; dns_name_t suffix; /* * DS records are found in the parent server. * Strip label to get the correct forwarder (if any). */ if (dns_rdatatype_atparent(fctx->type) && dns_name_countlabels(name) > 1) { unsigned int labels; dns_name_init(&suffix, NULL); labels = dns_name_countlabels(name); dns_name_getlabelsequence(name, 1, labels - 1, &suffix); name = &suffix; } result = dns_fwdtable_find(res->view->fwdtable, name, &forwarders); if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH) { fwd = ISC_LIST_HEAD(forwarders->fwdrs); fctx->fwdpolicy = forwarders->fwdpolicy; dns_name_copy(&forwarders->name, fctx->fwdname); if (fctx->fwdpolicy == dns_fwdpolicy_only && isstrictsubdomain(&forwarders->name, fctx->domain)) { fcount_decr(fctx); dns_name_copy(&forwarders->name, fctx->domain); result = fcount_incr(fctx, true); if (result != ISC_R_SUCCESS) { dns_forwarders_detach(&forwarders); return result; } } dns_forwarders_detach(&forwarders); } } while (fwd != NULL) { if ((isc_sockaddr_pf(&fwd->addr) == AF_INET && res->dispatches4 == NULL) || (isc_sockaddr_pf(&fwd->addr) == AF_INET6 && res->dispatches6 == NULL)) { fwd = ISC_LIST_NEXT(fwd, link); continue; } ai = NULL; result = dns_adb_findaddrinfo(fctx->adb, &fwd->addr, &ai, 0); if (result == ISC_R_SUCCESS) { dns_adbaddrinfo_t *cur; ai->flags |= FCTX_ADDRINFO_FORWARDER; if (fwd->tlsname != NULL) { result = dns_view_gettransport( res->view, DNS_TRANSPORT_TLS, fwd->tlsname, &ai->transport); if (result != ISC_R_SUCCESS) { dns_adb_freeaddrinfo(fctx->adb, &ai); goto next; } } cur = ISC_LIST_HEAD(fctx->forwaddrs); while (cur != NULL && cur->srtt < ai->srtt) { cur = ISC_LIST_NEXT(cur, publink); } if (cur != NULL) { ISC_LIST_INSERTBEFORE(fctx->forwaddrs, cur, ai, publink); } else { ISC_LIST_APPEND(fctx->forwaddrs, ai, publink); } } next: fwd = ISC_LIST_NEXT(fwd, link); } /* * If the forwarding policy is "only", we don't need the * addresses of the nameservers. */ if (fctx->fwdpolicy == dns_fwdpolicy_only) { goto out; } /* * Normal nameservers. */ normal_nses: stdoptions = DNS_ADBFIND_WANTEVENT | DNS_ADBFIND_EMPTYEVENT; if (fctx->restarts == 1) { /* * To avoid sending out a flood of queries likely to * result in NXRRSET, we suppress fetches for address * families we don't have the first time through, * provided that we have addresses in some family we * can use. * * We don't want to set this option all the time, since * if fctx->restarts > 1, we've clearly been having * trouble with the addresses we had, so getting more * could help. */ stdoptions |= DNS_ADBFIND_AVOIDFETCHES; } if (res->dispatches4 != NULL) { stdoptions |= DNS_ADBFIND_INET; } if (res->dispatches6 != NULL) { stdoptions |= DNS_ADBFIND_INET6; } if ((stdoptions & DNS_ADBFIND_ADDRESSMASK) == 0) { return DNS_R_SERVFAIL; } now = isc_stdtime_now(); all_spilled = true; /* resets to false below after the first success */ INSIST(ISC_LIST_EMPTY(fctx->finds)); INSIST(ISC_LIST_EMPTY(fctx->altfinds)); for (result = dns_rdataset_first(&fctx->nameservers); result == ISC_R_SUCCESS; result = dns_rdataset_next(&fctx->nameservers)) { bool overquota = false; unsigned int static_stub = 0; dns_rdataset_current(&fctx->nameservers, &rdata); /* * Extract the name from the NS record. */ result = dns_rdata_tostruct(&rdata, &ns, NULL); if (result != ISC_R_SUCCESS) { continue; } if (STATICSTUB(&fctx->nameservers) && dns_name_equal(&ns.name, fctx->domain)) { static_stub = DNS_ADBFIND_STATICSTUB; } if (no_addresses > NS_FAIL_LIMIT && dns_rdataset_count(&fctx->nameservers) > NS_RR_LIMIT) { stdoptions |= DNS_ADBFIND_NOFETCH; } findname(fctx, &ns.name, 0, stdoptions | static_stub, 0, now, &overquota, &need_alternate, &no_addresses); if (!overquota) { all_spilled = false; } dns_rdata_reset(&rdata); dns_rdata_freestruct(&ns); if (++ns_processed >= NS_PROCESSING_LIMIT) { result = ISC_R_NOMORE; break; } } if (result != ISC_R_NOMORE) { return result; } /* * Do we need to use 6 to 4? */ if (need_alternate) { int family; alternate_t *a; family = (res->dispatches6 != NULL) ? AF_INET6 : AF_INET; for (a = ISC_LIST_HEAD(res->alternates); a != NULL; a = ISC_LIST_NEXT(a, link)) { if (!a->isaddress) { findname(fctx, &a->_u._n.name, a->_u._n.port, stdoptions, FCTX_ADDRINFO_DUALSTACK, now, NULL, NULL, NULL); continue; } if (isc_sockaddr_pf(&a->_u.addr) != family) { continue; } ai = NULL; result = dns_adb_findaddrinfo(fctx->adb, &a->_u.addr, &ai, 0); if (result == ISC_R_SUCCESS) { dns_adbaddrinfo_t *cur; ai->flags |= FCTX_ADDRINFO_FORWARDER; ai->flags |= FCTX_ADDRINFO_DUALSTACK; cur = ISC_LIST_HEAD(fctx->altaddrs); while (cur != NULL && cur->srtt < ai->srtt) { cur = ISC_LIST_NEXT(cur, publink); } if (cur != NULL) { ISC_LIST_INSERTBEFORE(fctx->altaddrs, cur, ai, publink); } else { ISC_LIST_APPEND(fctx->altaddrs, ai, publink); } } } } out: /* * Mark all known bad servers. */ all_bad = mark_bad(fctx); /* * How are we doing? */ if (all_bad) { /* * We've got no addresses. */ if (atomic_load_acquire(&fctx->pending) > 0) { /* * We're fetching the addresses, but don't have * any yet. Tell the caller to wait for an * answer. */ result = DNS_R_WAIT; } else { /* * We've lost completely. We don't know any * addresses, and the ADB has told us it can't * get them. */ FCTXTRACE("no addresses"); result = ISC_R_FAILURE; /* * If all of the addresses found were over the * fetches-per-server quota, return the * configured response. */ if (all_spilled) { result = res->quotaresp[dns_quotatype_server]; inc_stats(res, dns_resstatscounter_serverquota); } } } else { /* * We've found some addresses. We might still be * looking for more addresses. */ sort_finds(&fctx->finds, res->view->v6bias); sort_finds(&fctx->altfinds, 0); result = ISC_R_SUCCESS; } return result; } static void possibly_mark(fetchctx_t *fctx, dns_adbaddrinfo_t *addr) { isc_netaddr_t na; isc_sockaddr_t *sa = &addr->sockaddr; bool aborted = false; bool bogus; dns_acl_t *blackhole; isc_netaddr_t ipaddr; dns_peer_t *peer = NULL; dns_resolver_t *res = fctx->res; const char *msg = NULL; isc_netaddr_fromsockaddr(&ipaddr, sa); blackhole = dns_dispatchmgr_getblackhole(res->view->dispatchmgr); (void)dns_peerlist_peerbyaddr(res->view->peers, &ipaddr, &peer); if (blackhole != NULL) { int match; if ((dns_acl_match(&ipaddr, NULL, blackhole, res->view->aclenv, &match, NULL) == ISC_R_SUCCESS) && match > 0) { aborted = true; } } if (peer != NULL && dns_peer_getbogus(peer, &bogus) == ISC_R_SUCCESS && bogus) { aborted = true; } if (aborted) { addr->flags |= FCTX_ADDRINFO_MARK; msg = "ignoring blackholed / bogus server: "; } else if (isc_sockaddr_isnetzero(sa)) { addr->flags |= FCTX_ADDRINFO_MARK; msg = "ignoring net zero address: "; } else if (isc_sockaddr_ismulticast(sa)) { addr->flags |= FCTX_ADDRINFO_MARK; msg = "ignoring multicast address: "; } else if (isc_sockaddr_isexperimental(sa)) { addr->flags |= FCTX_ADDRINFO_MARK; msg = "ignoring experimental address: "; } else if (sa->type.sa.sa_family != AF_INET6) { return; } else if (IN6_IS_ADDR_V4MAPPED(&sa->type.sin6.sin6_addr)) { addr->flags |= FCTX_ADDRINFO_MARK; msg = "ignoring IPv6 mapped IPV4 address: "; } else if (IN6_IS_ADDR_V4COMPAT(&sa->type.sin6.sin6_addr)) { addr->flags |= FCTX_ADDRINFO_MARK; msg = "ignoring IPv6 compatibility IPV4 address: "; } else { return; } if (isc_log_wouldlog(dns_lctx, ISC_LOG_DEBUG(3))) { char buf[ISC_NETADDR_FORMATSIZE]; isc_netaddr_fromsockaddr(&na, sa); isc_netaddr_format(&na, buf, sizeof(buf)); FCTXTRACE2(msg, buf); } } static dns_adbaddrinfo_t * fctx_nextaddress(fetchctx_t *fctx) { dns_adbfind_t *find, *start; dns_adbaddrinfo_t *addrinfo; dns_adbaddrinfo_t *faddrinfo; /* * Return the next untried address, if any. */ /* * Find the first unmarked forwarder (if any). */ for (addrinfo = ISC_LIST_HEAD(fctx->forwaddrs); addrinfo != NULL; addrinfo = ISC_LIST_NEXT(addrinfo, publink)) { if (!UNMARKED(addrinfo)) { continue; } possibly_mark(fctx, addrinfo); if (UNMARKED(addrinfo)) { addrinfo->flags |= FCTX_ADDRINFO_MARK; fctx->find = NULL; fctx->forwarding = true; /* * QNAME minimization is disabled when * forwarding, and has to remain disabled if * we switch back to normal recursion; otherwise * forwarding could leave us in an inconsistent * state. */ fctx->minimized = false; return addrinfo; } } /* * No forwarders. Move to the next find. */ fctx->forwarding = false; FCTX_ATTR_SET(fctx, FCTX_ATTR_TRIEDFIND); find = fctx->find; if (find == NULL) { find = ISC_LIST_HEAD(fctx->finds); } else { find = ISC_LIST_NEXT(find, publink); if (find == NULL) { find = ISC_LIST_HEAD(fctx->finds); } } /* * Find the first unmarked addrinfo. */ addrinfo = NULL; if (find != NULL) { start = find; do { for (addrinfo = ISC_LIST_HEAD(find->list); addrinfo != NULL; addrinfo = ISC_LIST_NEXT(addrinfo, publink)) { if (!UNMARKED(addrinfo)) { continue; } possibly_mark(fctx, addrinfo); if (UNMARKED(addrinfo)) { addrinfo->flags |= FCTX_ADDRINFO_MARK; break; } } if (addrinfo != NULL) { break; } find = ISC_LIST_NEXT(find, publink); if (find == NULL) { find = ISC_LIST_HEAD(fctx->finds); } } while (find != start); } fctx->find = find; if (addrinfo != NULL) { return addrinfo; } /* * No nameservers left. Try alternates. */ FCTX_ATTR_SET(fctx, FCTX_ATTR_TRIEDALT); find = fctx->altfind; if (find == NULL) { find = ISC_LIST_HEAD(fctx->altfinds); } else { find = ISC_LIST_NEXT(find, publink); if (find == NULL) { find = ISC_LIST_HEAD(fctx->altfinds); } } /* * Find the first unmarked addrinfo. */ addrinfo = NULL; if (find != NULL) { start = find; do { for (addrinfo = ISC_LIST_HEAD(find->list); addrinfo != NULL; addrinfo = ISC_LIST_NEXT(addrinfo, publink)) { if (!UNMARKED(addrinfo)) { continue; } possibly_mark(fctx, addrinfo); if (UNMARKED(addrinfo)) { addrinfo->flags |= FCTX_ADDRINFO_MARK; break; } } if (addrinfo != NULL) { break; } find = ISC_LIST_NEXT(find, publink); if (find == NULL) { find = ISC_LIST_HEAD(fctx->altfinds); } } while (find != start); } faddrinfo = addrinfo; /* * See if we have a better alternate server by address. */ for (addrinfo = ISC_LIST_HEAD(fctx->altaddrs); addrinfo != NULL; addrinfo = ISC_LIST_NEXT(addrinfo, publink)) { if (!UNMARKED(addrinfo)) { continue; } possibly_mark(fctx, addrinfo); if (UNMARKED(addrinfo) && (faddrinfo == NULL || addrinfo->srtt < faddrinfo->srtt)) { if (faddrinfo != NULL) { faddrinfo->flags &= ~FCTX_ADDRINFO_MARK; } addrinfo->flags |= FCTX_ADDRINFO_MARK; break; } } if (addrinfo == NULL) { addrinfo = faddrinfo; fctx->altfind = find; } return addrinfo; } static void fctx_try(fetchctx_t *fctx, bool retrying) { isc_result_t result; dns_adbaddrinfo_t *addrinfo = NULL; dns_resolver_t *res = NULL; FCTXTRACE5("try", "fctx->qc=", isc_counter_used(fctx->qc)); REQUIRE(!ADDRWAIT(fctx)); REQUIRE(fctx->tid == isc_tid()); res = fctx->res; /* We've already exceeded maximum query count */ if (isc_counter_used(fctx->qc) > res->maxqueries) { isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER, ISC_LOG_DEBUG(3), "exceeded max queries resolving '%s' " "(querycount=%u, maxqueries=%u)", fctx->info, isc_counter_used(fctx->qc), res->maxqueries); result = DNS_R_SERVFAIL; goto done; } addrinfo = fctx_nextaddress(fctx); /* Try to find an address that isn't over quota */ while (addrinfo != NULL && dns_adb_overquota(fctx->adb, addrinfo)) { addrinfo = fctx_nextaddress(fctx); } if (addrinfo == NULL) { /* We have no more addresses. Start over. */ fctx_cancelqueries(fctx, true, false); fctx_cleanup(fctx); result = fctx_getaddresses(fctx); switch (result) { case ISC_R_SUCCESS: break; case DNS_R_WAIT: /* Sleep waiting for addresses. */ FCTXTRACE("addrwait"); FCTX_ATTR_SET(fctx, FCTX_ATTR_ADDRWAIT); return; default: goto done; } addrinfo = fctx_nextaddress(fctx); while (addrinfo != NULL && dns_adb_overquota(fctx->adb, addrinfo)) { addrinfo = fctx_nextaddress(fctx); } /* * While we may have addresses from the ADB, they * might be bad ones. In this case, return SERVFAIL. */ if (addrinfo == NULL) { result = DNS_R_SERVFAIL; goto done; } } /* * We're minimizing and we're not yet at the final NS - * we need to launch a query for NS for 'upper' domain */ if (fctx->minimized && !fctx->forwarding) { unsigned int options = fctx->options; options &= ~DNS_FETCHOPT_QMINIMIZE; /* * Is another QNAME minimization fetch still running? */ if (fctx->qminfetch != NULL) { bool validfctx = (DNS_FETCH_VALID(fctx->qminfetch) && VALID_FCTX(fctx->qminfetch->private)); char namebuf[DNS_NAME_FORMATSIZE]; char typebuf[DNS_RDATATYPE_FORMATSIZE]; dns_name_format(fctx->qminname, namebuf, sizeof(namebuf)); dns_rdatatype_format(fctx->qmintype, typebuf, sizeof(typebuf)); isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER, ISC_LOG_ERROR, "fctx %p(%s): attempting QNAME " "minimization fetch for %s/%s but " "fetch %p(%s) still running", fctx, fctx->info, namebuf, typebuf, fctx->qminfetch, validfctx ? fctx->qminfetch->private->info : ""); result = DNS_R_SERVFAIL; goto done; } /* * Turn on NOFOLLOW in relaxed mode so that QNAME minimization * doesn't cause additional queries to resolve the target of the * QNAME minimization request when a referral is returned. This * will also reduce the impact of mis-matched NS RRsets where * the child's NS RRset is garbage. If a delegation is * discovered DNS_R_DELEGATION will be returned to resume_qmin. */ if ((options & DNS_FETCHOPT_QMIN_STRICT) == 0) { options |= DNS_FETCHOPT_NOFOLLOW; } fetchctx_ref(fctx); result = dns_resolver_createfetch( fctx->res, fctx->qminname, fctx->qmintype, fctx->domain, &fctx->nameservers, NULL, NULL, 0, options, 0, fctx->qc, fctx->loop, resume_qmin, fctx, &fctx->qminrrset, NULL, &fctx->qminfetch); if (result != ISC_R_SUCCESS) { fetchctx_unref(fctx); goto done; } return; } result = isc_counter_increment(fctx->qc); if (result != ISC_R_SUCCESS) { isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER, ISC_LOG_DEBUG(3), "exceeded max queries resolving '%s'", fctx->info); goto done; } result = fctx_query(fctx, addrinfo, fctx->options); if (result != ISC_R_SUCCESS) { goto done; } if (retrying) { inc_stats(res, dns_resstatscounter_retry); } done: if (result != ISC_R_SUCCESS) { fctx_done_detach(&fctx, result); } } static void resume_qmin(void *arg) { dns_fetchresponse_t *resp = (dns_fetchresponse_t *)arg; fetchctx_t *fctx = resp->arg; dns_resolver_t *res = NULL; isc_result_t result; unsigned int findoptions = 0; dns_name_t *fname = NULL, *dcname = NULL; dns_fixedname_t ffixed, dcfixed; REQUIRE(VALID_FCTX(fctx)); res = fctx->res; REQUIRE(fctx->tid == isc_tid()); FCTXTRACE("resume_qmin"); fname = dns_fixedname_initname(&ffixed); dcname = dns_fixedname_initname(&dcfixed); if (resp->node != NULL) { dns_db_detachnode(resp->db, &resp->node); } if (resp->db != NULL) { dns_db_detach(&resp->db); } if (dns_rdataset_isassociated(resp->rdataset)) { dns_rdataset_disassociate(resp->rdataset); } result = resp->result; isc_mem_putanddetach(&resp->mctx, resp, sizeof(*resp)); LOCK(&fctx->lock); if (SHUTTINGDOWN(fctx)) { result = ISC_R_SHUTTINGDOWN; } UNLOCK(&fctx->lock); dns_resolver_destroyfetch(&fctx->qminfetch); /* * Beware, the switch() below is little bit tricky - the order of the * branches is important. */ switch (result) { case ISC_R_SHUTTINGDOWN: case ISC_R_CANCELED: goto cleanup; case DNS_R_NXDOMAIN: case DNS_R_NCACHENXDOMAIN: case DNS_R_FORMERR: case DNS_R_REMOTEFORMERR: case ISC_R_FAILURE: if ((fctx->options & DNS_FETCHOPT_QMIN_STRICT) != 0) { /* These results cause a hard fail in strict mode */ goto cleanup; } /* ...or disable minimization in relaxed mode */ fctx->qmin_labels = DNS_NAME_MAXLABELS; /* * We store the result. If we succeed in the end * we'll issue a warning that the server is * broken. */ fctx->qmin_warning = result; break; case ISC_R_SUCCESS: case DNS_R_DELEGATION: case DNS_R_NXRRSET: case DNS_R_NCACHENXRRSET: case DNS_R_CNAME: case DNS_R_DNAME: /* * We have previously detected a possible error of an * incorrect NXDOMAIN and now have a response that * indicates that it was an actual error. */ if (fctx->qmin_warning == DNS_R_NCACHENXDOMAIN || fctx->qmin_warning == DNS_R_NXDOMAIN) { fctx->force_qmin_warning = true; } /* * Any other result will *not* cause a failure in strict * mode, or cause minimization to be disabled in relaxed * mode. * * If DNS_R_DELEGATION is set here, it implies that * DNS_FETCHOPT_NOFOLLOW was set, and a delegation was * discovered but not followed; we will do so now. */ break; default: isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER, ISC_LOG_DEBUG(5), "QNAME minimization: unexpected result %s", isc_result_totext(result)); break; } if (dns_rdataset_isassociated(&fctx->nameservers)) { dns_rdataset_disassociate(&fctx->nameservers); } if (dns_rdatatype_atparent(fctx->type)) { findoptions |= DNS_DBFIND_NOEXACT; } result = dns_view_findzonecut(res->view, fctx->name, fname, dcname, fctx->now, findoptions, true, true, &fctx->nameservers, NULL); /* * DNS_R_NXDOMAIN here means we have not loaded the root zone * mirror yet - but DNS_R_NXDOMAIN is not a valid return value * when doing recursion, we need to patch it. */ if (result == DNS_R_NXDOMAIN) { result = DNS_R_SERVFAIL; } if (result != ISC_R_SUCCESS) { goto cleanup; } fcount_decr(fctx); dns_name_copy(fname, fctx->domain); result = fcount_incr(fctx, true); if (result != ISC_R_SUCCESS) { goto cleanup; } dns_name_copy(dcname, fctx->qmindcname); fctx->ns_ttl = fctx->nameservers.ttl; fctx->ns_ttl_ok = true; fctx_minimize_qname(fctx); if (!fctx->minimized) { /* * We have finished minimizing, but fctx->finds was * filled at the beginning of the run - now we need to * clear it before sending the final query to use proper * nameservers. */ fctx_cancelqueries(fctx, false, false); fctx_cleanup(fctx); } fctx_try(fctx, true); cleanup: if (result != ISC_R_SUCCESS) { /* An error occurred, tear down whole fctx */ fctx_done_unref(fctx, result); } fetchctx_detach(&fctx); } static void fctx_destroy(fetchctx_t *fctx) { dns_resolver_t *res = NULL; isc_sockaddr_t *sa = NULL, *next_sa = NULL; struct tried *tried = NULL; uint_fast32_t nfctx; REQUIRE(VALID_FCTX(fctx)); REQUIRE(ISC_LIST_EMPTY(fctx->resps)); REQUIRE(ISC_LIST_EMPTY(fctx->queries)); REQUIRE(ISC_LIST_EMPTY(fctx->finds)); REQUIRE(ISC_LIST_EMPTY(fctx->altfinds)); REQUIRE(atomic_load_acquire(&fctx->pending) == 0); REQUIRE(ISC_LIST_EMPTY(fctx->validators)); REQUIRE(fctx->state != fetchstate_active); FCTXTRACE("destroy"); fctx->magic = 0; res = fctx->res; dec_stats(res, dns_resstatscounter_nfetch); nfctx = atomic_fetch_sub_release(&res->nfctx, 1); INSIST(nfctx > 0); /* Free bad */ for (sa = ISC_LIST_HEAD(fctx->bad); sa != NULL; sa = next_sa) { next_sa = ISC_LIST_NEXT(sa, link); ISC_LIST_UNLINK(fctx->bad, sa, link); isc_mem_put(fctx->mctx, sa, sizeof(*sa)); } for (tried = ISC_LIST_HEAD(fctx->edns); tried != NULL; tried = ISC_LIST_HEAD(fctx->edns)) { ISC_LIST_UNLINK(fctx->edns, tried, link); isc_mem_put(fctx->mctx, tried, sizeof(*tried)); } for (sa = ISC_LIST_HEAD(fctx->bad_edns); sa != NULL; sa = next_sa) { next_sa = ISC_LIST_NEXT(sa, link); ISC_LIST_UNLINK(fctx->bad_edns, sa, link); isc_mem_put(fctx->mctx, sa, sizeof(*sa)); } isc_counter_detach(&fctx->qc); fcount_decr(fctx); dns_message_detach(&fctx->qmessage); if (dns_rdataset_isassociated(&fctx->nameservers)) { dns_rdataset_disassociate(&fctx->nameservers); } dns_db_detach(&fctx->cache); dns_adb_detach(&fctx->adb); dns_resolver_detach(&fctx->res); isc_mutex_destroy(&fctx->lock); isc_mem_free(fctx->mctx, fctx->info); isc_mem_putanddetach(&fctx->mctx, fctx, sizeof(*fctx)); } static void fctx_expired(void *arg) { fetchctx_t *fctx = (fetchctx_t *)arg; REQUIRE(VALID_FCTX(fctx)); REQUIRE(fctx->tid == isc_tid()); isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO, "shut down hung fetch while resolving %p(%s)", fctx, fctx->info); fctx_done_detach(&fctx, DNS_R_SERVFAIL); } static void fctx_shutdown(void *arg) { fetchctx_t *fctx = arg; REQUIRE(VALID_FCTX(fctx)); fctx_done_unref(fctx, ISC_R_SHUTTINGDOWN); fetchctx_detach(&fctx); } static void fctx_start(void *arg) { fetchctx_t *fctx = (fetchctx_t *)arg; REQUIRE(VALID_FCTX(fctx)); FCTXTRACE("start"); LOCK(&fctx->lock); if (SHUTTINGDOWN(fctx)) { UNLOCK(&fctx->lock); goto detach; } /* * Normal fctx startup. */ fctx->state = fetchstate_active; UNLOCK(&fctx->lock); /* * As a backstop, we also set a timer to stop the fetch * if in-band netmgr timeouts don't work. It will fire two * seconds after the fetch should have finished. (This * should be enough of a gap to avoid the timer firing * while a response is being processed normally.) */ fctx_starttimer(fctx); fctx_try(fctx, false); detach: fetchctx_detach(&fctx); } /* * Fetch Creation, Joining, and Cancellation. */ static void fctx_add_event(fetchctx_t *fctx, isc_loop_t *loop, const isc_sockaddr_t *client, dns_messageid_t id, isc_job_cb cb, void *arg, dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset, dns_fetch_t *fetch) { dns_fetchresponse_t *resp = NULL; FCTXTRACE("addevent"); resp = isc_mem_get(fctx->mctx, sizeof(*resp)); *resp = (dns_fetchresponse_t){ .result = DNS_R_SERVFAIL, .qtype = fctx->type, .rdataset = rdataset, .sigrdataset = sigrdataset, .fetch = fetch, .client = client, .id = id, .loop = loop, .cb = cb, .arg = arg, .link = ISC_LINK_INITIALIZER, }; isc_mem_attach(fctx->mctx, &resp->mctx); resp->foundname = dns_fixedname_initname(&resp->fname); /* * Store the sigrdataset in the first resp in case it is needed * by any of the events. */ if (resp->sigrdataset != NULL) { ISC_LIST_PREPEND(fctx->resps, resp, link); } else { ISC_LIST_APPEND(fctx->resps, resp, link); } } static void fctx_join(fetchctx_t *fctx, isc_loop_t *loop, const isc_sockaddr_t *client, dns_messageid_t id, isc_job_cb cb, void *arg, dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset, dns_fetch_t *fetch) { FCTXTRACE("join"); REQUIRE(!SHUTTINGDOWN(fctx)); fctx_add_event(fctx, loop, client, id, cb, arg, rdataset, sigrdataset, fetch); fetch->magic = DNS_FETCH_MAGIC; fetchctx_attach(fctx, &fetch->private); } static void log_ns_ttl(fetchctx_t *fctx, const char *where) { char namebuf[DNS_NAME_FORMATSIZE]; char domainbuf[DNS_NAME_FORMATSIZE]; dns_name_format(fctx->name, namebuf, sizeof(namebuf)); dns_name_format(fctx->domain, domainbuf, sizeof(domainbuf)); isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER, ISC_LOG_DEBUG(10), "log_ns_ttl: fctx %p: %s: %s (in '%s'?): %u %u", fctx, where, namebuf, domainbuf, fctx->ns_ttl_ok, fctx->ns_ttl); } static isc_result_t fctx_create(dns_resolver_t *res, isc_loop_t *loop, const dns_name_t *name, dns_rdatatype_t type, const dns_name_t *domain, dns_rdataset_t *nameservers, const isc_sockaddr_t *client, unsigned int options, unsigned int depth, isc_counter_t *qc, fetchctx_t **fctxp) { fetchctx_t *fctx = NULL; isc_result_t result; isc_result_t iresult; isc_interval_t interval; unsigned int findoptions = 0; char buf[DNS_NAME_FORMATSIZE + DNS_RDATATYPE_FORMATSIZE + 1]; uint_fast32_t nfctx; isc_mem_t *mctx = isc_loop_getmctx(loop); size_t p; /* * Caller must be holding the lock for 'bucket' */ REQUIRE(fctxp != NULL && *fctxp == NULL); fctx = isc_mem_get(mctx, sizeof(*fctx)); *fctx = (fetchctx_t){ .type = type, .qmintype = type, .options = options, .tid = isc_tid(), .state = fetchstate_active, .depth = depth, .qmin_labels = 1, .fwdpolicy = dns_fwdpolicy_none, .result = ISC_R_FAILURE, .loop = loop, .nvalidations = atomic_load_relaxed(&res->maxvalidations), .nfails = atomic_load_relaxed(&res->maxvalidationfails), }; isc_mem_attach(mctx, &fctx->mctx); dns_resolver_attach(res, &fctx->res); isc_mutex_init(&fctx->lock); /* * Make fctx->info point to a copy of a formatted string * "name/type". FCTXTRACE won't work until this is done. */ dns_name_format(name, buf, sizeof(buf)); p = strlcat(buf, "/", sizeof(buf)); INSIST(p + DNS_RDATATYPE_FORMATSIZE < sizeof(buf)); dns_rdatatype_format(type, buf + p, sizeof(buf) - p); fctx->info = isc_mem_strdup(fctx->mctx, buf); FCTXTRACE("create"); if (qc != NULL) { isc_counter_attach(qc, &fctx->qc); isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER, ISC_LOG_DEBUG(9), "fctx %p(%s): attached to counter %p (%d)", fctx, fctx->info, fctx->qc, isc_counter_used(fctx->qc)); } else { result = isc_counter_create(fctx->mctx, res->maxqueries, &fctx->qc); if (result != ISC_R_SUCCESS) { goto cleanup_fetch; } isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER, ISC_LOG_DEBUG(9), "fctx %p(%s): created counter %p", fctx, fctx->info, fctx->qc); } #if DNS_RESOLVER_TRACE fprintf(stderr, "fetchctx__init:%s:%s:%d:%p:%p->references = 1\n", __func__, __FILE__, __LINE__, fctx, fctx); #endif isc_refcount_init(&fctx->references, 1); ISC_LIST_INIT(fctx->queries); ISC_LIST_INIT(fctx->finds); ISC_LIST_INIT(fctx->altfinds); ISC_LIST_INIT(fctx->forwaddrs); ISC_LIST_INIT(fctx->altaddrs); ISC_LIST_INIT(fctx->forwarders); ISC_LIST_INIT(fctx->bad); ISC_LIST_INIT(fctx->edns); ISC_LIST_INIT(fctx->bad_edns); ISC_LIST_INIT(fctx->validators); atomic_init(&fctx->attributes, 0); fctx->name = dns_fixedname_initname(&fctx->fname); fctx->nsname = dns_fixedname_initname(&fctx->nsfname); fctx->domain = dns_fixedname_initname(&fctx->dfname); fctx->qminname = dns_fixedname_initname(&fctx->qminfname); fctx->qmindcname = dns_fixedname_initname(&fctx->qmindcfname); fctx->fwdname = dns_fixedname_initname(&fctx->fwdfname); dns_name_copy(name, fctx->name); dns_name_copy(name, fctx->qminname); dns_rdataset_init(&fctx->nameservers); dns_rdataset_init(&fctx->qminrrset); dns_rdataset_init(&fctx->nsrrset); fctx->start = isc_time_now(); fctx->now = (isc_stdtime_t)fctx->start.seconds; if (client != NULL) { isc_sockaddr_format(client, fctx->clientstr, sizeof(fctx->clientstr)); } else { strlcpy(fctx->clientstr, "", sizeof(fctx->clientstr)); } if (domain == NULL) { dns_forwarders_t *forwarders = NULL; unsigned int labels; const dns_name_t *fwdname = name; dns_name_t suffix; /* * DS records are found in the parent server. Strip one * leading label from the name (to be used in finding * the forwarder). */ if (dns_rdatatype_atparent(fctx->type) && dns_name_countlabels(name) > 1) { dns_name_init(&suffix, NULL); labels = dns_name_countlabels(name); dns_name_getlabelsequence(name, 1, labels - 1, &suffix); fwdname = &suffix; } /* Find the forwarder for this name. */ result = dns_fwdtable_find(fctx->res->view->fwdtable, fwdname, &forwarders); if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH) { fctx->fwdpolicy = forwarders->fwdpolicy; dns_name_copy(&forwarders->name, fctx->fwdname); dns_forwarders_detach(&forwarders); } if (fctx->fwdpolicy == dns_fwdpolicy_only) { /* * We're in forward-only mode. Set the query * domain. */ dns_name_copy(fctx->fwdname, fctx->domain); dns_name_copy(fctx->fwdname, fctx->qmindcname); /* * Disable query minimization */ options &= ~DNS_FETCHOPT_QMINIMIZE; } else { dns_fixedname_t dcfixed; dns_name_t *dcname = dns_fixedname_initname(&dcfixed); /* * The caller didn't supply a query domain and * nameservers, and we're not in forward-only * mode, so find the best nameservers to use. */ if (dns_rdatatype_atparent(fctx->type)) { findoptions |= DNS_DBFIND_NOEXACT; } result = dns_view_findzonecut( res->view, name, fctx->fwdname, dcname, fctx->now, findoptions, true, true, &fctx->nameservers, NULL); if (result != ISC_R_SUCCESS) { goto cleanup_nameservers; } dns_name_copy(fctx->fwdname, fctx->domain); dns_name_copy(dcname, fctx->qmindcname); fctx->ns_ttl = fctx->nameservers.ttl; fctx->ns_ttl_ok = true; } } else { dns_name_copy(domain, fctx->domain); dns_name_copy(domain, fctx->qmindcname); dns_rdataset_clone(nameservers, &fctx->nameservers); fctx->ns_ttl = fctx->nameservers.ttl; fctx->ns_ttl_ok = true; } /* * Exempt prefetch queries from the fetches-per-zone quota check */ if ((fctx->options & DNS_FETCHOPT_PREFETCH) == 0) { /* * Are there too many simultaneous queries for this domain? */ result = fcount_incr(fctx, false); if (result != ISC_R_SUCCESS) { result = fctx->res->quotaresp[dns_quotatype_zone]; inc_stats(res, dns_resstatscounter_zonequota); goto cleanup_nameservers; } } log_ns_ttl(fctx, "fctx_create"); if (!dns_name_issubdomain(fctx->name, fctx->domain)) { dns_name_format(fctx->domain, buf, sizeof(buf)); UNEXPECTED_ERROR("'%s' is not subdomain of '%s'", fctx->info, buf); result = ISC_R_UNEXPECTED; goto cleanup_fcount; } dns_message_create(fctx->mctx, fctx->res->namepools[fctx->tid], fctx->res->rdspools[fctx->tid], DNS_MESSAGE_INTENTRENDER, &fctx->qmessage); /* * Compute an expiration time for the entire fetch. */ isc_interval_set(&interval, res->query_timeout / 1000, res->query_timeout % 1000 * 1000000); iresult = isc_time_nowplusinterval(&fctx->expires, &interval); if (iresult != ISC_R_SUCCESS) { UNEXPECTED_ERROR("isc_time_nowplusinterval: %s", isc_result_totext(iresult)); result = ISC_R_UNEXPECTED; goto cleanup_qmessage; } /* * Default retry interval initialization. We set the interval * now mostly so it won't be uninitialized. It will be set to * the correct value before a query is issued. */ isc_interval_set(&fctx->interval, 2, 0); /* * Attach to the view's cache and adb. */ dns_db_attach(res->view->cachedb, &fctx->cache); dns_view_getadb(res->view, &fctx->adb); ISC_LIST_INIT(fctx->resps); ISC_LINK_INIT(fctx, link); fctx->magic = FCTX_MAGIC; /* * If qname minimization is enabled we need to trim * the name in fctx to proper length. */ if ((options & DNS_FETCHOPT_QMINIMIZE) != 0) { fctx->ip6arpaskip = (options & DNS_FETCHOPT_QMIN_SKIP_IP6A) != 0 && dns_name_issubdomain(fctx->name, &ip6_arpa); fctx_minimize_qname(fctx); } nfctx = atomic_fetch_add_relaxed(&res->nfctx, 1); INSIST(nfctx < UINT32_MAX); inc_stats(res, dns_resstatscounter_nfetch); isc_timer_create(fctx->loop, fctx_expired, fctx, &fctx->timer); *fctxp = fctx; return ISC_R_SUCCESS; cleanup_qmessage: dns_message_detach(&fctx->qmessage); cleanup_fcount: fcount_decr(fctx); cleanup_nameservers: if (dns_rdataset_isassociated(&fctx->nameservers)) { dns_rdataset_disassociate(&fctx->nameservers); } isc_mem_free(fctx->mctx, fctx->info); isc_counter_detach(&fctx->qc); cleanup_fetch: dns_resolver_detach(&fctx->res); isc_mem_putanddetach(&fctx->mctx, fctx, sizeof(*fctx)); return result; } /* * Handle Responses */ static bool is_lame(fetchctx_t *fctx, dns_message_t *message) { dns_name_t *name; dns_rdataset_t *rdataset; isc_result_t result; if (message->rcode != dns_rcode_noerror && message->rcode != dns_rcode_yxdomain && message->rcode != dns_rcode_nxdomain) { return false; } if (message->counts[DNS_SECTION_ANSWER] != 0) { return false; } if (message->counts[DNS_SECTION_AUTHORITY] == 0) { return false; } result = dns_message_firstname(message, DNS_SECTION_AUTHORITY); while (result == ISC_R_SUCCESS) { name = NULL; dns_message_currentname(message, DNS_SECTION_AUTHORITY, &name); for (rdataset = ISC_LIST_HEAD(name->list); rdataset != NULL; rdataset = ISC_LIST_NEXT(rdataset, link)) { dns_namereln_t namereln; int order; unsigned int labels; if (rdataset->type != dns_rdatatype_ns) { continue; } namereln = dns_name_fullcompare(name, fctx->domain, &order, &labels); if (namereln == dns_namereln_equal && (message->flags & DNS_MESSAGEFLAG_AA) != 0) { return false; } if (namereln == dns_namereln_subdomain) { return false; } return true; } result = dns_message_nextname(message, DNS_SECTION_AUTHORITY); } return false; } static void log_lame(fetchctx_t *fctx, dns_adbaddrinfo_t *addrinfo) { char namebuf[DNS_NAME_FORMATSIZE]; char domainbuf[DNS_NAME_FORMATSIZE]; char addrbuf[ISC_SOCKADDR_FORMATSIZE]; dns_name_format(fctx->name, namebuf, sizeof(namebuf)); dns_name_format(fctx->domain, domainbuf, sizeof(domainbuf)); isc_sockaddr_format(&addrinfo->sockaddr, addrbuf, sizeof(addrbuf)); isc_log_write(dns_lctx, DNS_LOGCATEGORY_LAME_SERVERS, DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO, "lame server resolving '%s' (in '%s'?): %s", namebuf, domainbuf, addrbuf); } static void log_formerr(fetchctx_t *fctx, const char *format, ...) { char nsbuf[ISC_SOCKADDR_FORMATSIZE]; char msgbuf[2048]; va_list args; va_start(args, format); vsnprintf(msgbuf, sizeof(msgbuf), format, args); va_end(args); isc_sockaddr_format(&fctx->addrinfo->sockaddr, nsbuf, sizeof(nsbuf)); isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER, ISC_LOG_NOTICE, "DNS format error from %s resolving %s for %s: %s", nsbuf, fctx->info, fctx->clientstr, msgbuf); } static isc_result_t same_question(fetchctx_t *fctx, dns_message_t *message) { isc_result_t result; dns_name_t *name = NULL; dns_rdataset_t *rdataset = NULL; /* * Caller must be holding the fctx lock. */ /* * XXXRTH Currently we support only one question. */ if (message->counts[DNS_SECTION_QUESTION] == 0) { if ((message->flags & DNS_MESSAGEFLAG_TC) != 0) { /* * If TC=1 and the question section is empty, we * accept the reply message as a truncated * answer, to be retried over TCP. * * It is really a FORMERR condition, but this is * a workaround to accept replies from some * implementations. * * Because the question section matching is not * performed, the worst that could happen is * that an attacker who gets past the ID and * source port checks can force the use of * TCP. This is considered an acceptable risk. */ log_formerr(fctx, "empty question section, " "accepting it anyway as TC=1"); return ISC_R_SUCCESS; } else { log_formerr(fctx, "empty question section"); return DNS_R_FORMERR; } } else if (message->counts[DNS_SECTION_QUESTION] > 1) { log_formerr(fctx, "too many questions"); return DNS_R_FORMERR; } result = dns_message_firstname(message, DNS_SECTION_QUESTION); if (result != ISC_R_SUCCESS) { return result; } dns_message_currentname(message, DNS_SECTION_QUESTION, &name); rdataset = ISC_LIST_HEAD(name->list); INSIST(rdataset != NULL); INSIST(ISC_LIST_NEXT(rdataset, link) == NULL); if (fctx->type != rdataset->type || fctx->res->rdclass != rdataset->rdclass || !dns_name_equal(fctx->name, name)) { char namebuf[DNS_NAME_FORMATSIZE]; char classbuf[DNS_RDATACLASS_FORMATSIZE]; char typebuf[DNS_RDATATYPE_FORMATSIZE]; dns_name_format(name, namebuf, sizeof(namebuf)); dns_rdataclass_format(rdataset->rdclass, classbuf, sizeof(classbuf)); dns_rdatatype_format(rdataset->type, typebuf, sizeof(typebuf)); log_formerr(fctx, "question section mismatch: got %s/%s/%s", namebuf, classbuf, typebuf); return DNS_R_FORMERR; } return ISC_R_SUCCESS; } static void clone_results(fetchctx_t *fctx) { dns_fetchresponse_t *resp = NULL, *hresp = NULL; FCTXTRACE("clone_results"); /* * Set up any other resps to have the same data as the first. * * Caller must be holding the appropriate lock. */ fctx->cloned = true; for (resp = ISC_LIST_HEAD(fctx->resps); resp != NULL; resp = ISC_LIST_NEXT(resp, link)) { /* This is the head resp; keep a pointer and move on */ if (hresp == NULL) { hresp = ISC_LIST_HEAD(fctx->resps); continue; } resp->result = hresp->result; dns_name_copy(hresp->foundname, resp->foundname); dns_db_attach(hresp->db, &resp->db); dns_db_attachnode(hresp->db, hresp->node, &resp->node); INSIST(hresp->rdataset != NULL); INSIST(resp->rdataset != NULL); if (dns_rdataset_isassociated(hresp->rdataset)) { dns_rdataset_clone(hresp->rdataset, resp->rdataset); } INSIST(!(hresp->sigrdataset == NULL && resp->sigrdataset != NULL)); if (hresp->sigrdataset != NULL && dns_rdataset_isassociated(hresp->sigrdataset) && resp->sigrdataset != NULL) { dns_rdataset_clone(hresp->sigrdataset, resp->sigrdataset); } } } #define CACHE(r) (((r)->attributes & DNS_RDATASETATTR_CACHE) != 0) #define ANSWER(r) (((r)->attributes & DNS_RDATASETATTR_ANSWER) != 0) #define ANSWERSIG(r) (((r)->attributes & DNS_RDATASETATTR_ANSWERSIG) != 0) #define EXTERNAL(r) (((r)->attributes & DNS_RDATASETATTR_EXTERNAL) != 0) #define CHAINING(r) (((r)->attributes & DNS_RDATASETATTR_CHAINING) != 0) #define CHASE(r) (((r)->attributes & DNS_RDATASETATTR_CHASE) != 0) #define CHECKNAMES(r) (((r)->attributes & DNS_RDATASETATTR_CHECKNAMES) != 0) /* * Cancel validators associated with '*fctx' if it is ready to be * destroyed (i.e., no queries waiting for it and no pending ADB finds). * Caller must hold fctx bucket lock. * * Requires: * '*fctx' is shutting down. */ static void maybe_cancel_validators(fetchctx_t *fctx) { if (atomic_load_acquire(&fctx->pending) != 0 || atomic_load_acquire(&fctx->nqueries) != 0) { return; } REQUIRE(SHUTTINGDOWN(fctx)); for (dns_validator_t *validator = ISC_LIST_HEAD(fctx->validators); validator != NULL; validator = ISC_LIST_NEXT(validator, link)) { dns_validator_cancel(validator); } } /* * typemap with just RRSIG(46) and NSEC(47) bits set. * * Bitmap calculation from dns_nsec_setbit: * * 46 47 * shift = 7 - (type % 8); 0 1 * mask = 1 << shift; 0x02 0x01 * array[type / 8] |= mask; * * Window (0), bitmap length (6), and bitmap. */ static const unsigned char minimal_typemap[] = { 0, 6, 0, 0, 0, 0, 0, 0x03 }; static bool is_minimal_nsec(dns_rdataset_t *nsecset) { dns_rdataset_t rdataset; isc_result_t result; dns_rdataset_init(&rdataset); dns_rdataset_clone(nsecset, &rdataset); for (result = dns_rdataset_first(&rdataset); result == ISC_R_SUCCESS; result = dns_rdataset_next(&rdataset)) { dns_rdata_t rdata = DNS_RDATA_INIT; dns_rdata_nsec_t nsec; dns_rdataset_current(&rdataset, &rdata); result = dns_rdata_tostruct(&rdata, &nsec, NULL); RUNTIME_CHECK(result == ISC_R_SUCCESS); if (nsec.len == sizeof(minimal_typemap) && memcmp(nsec.typebits, minimal_typemap, nsec.len) == 0) { dns_rdataset_disassociate(&rdataset); return true; } } dns_rdataset_disassociate(&rdataset); return false; } /* * If there is a SOA record in the type map then there must be a DNSKEY. */ static bool check_soa_and_dnskey(dns_rdataset_t *nsecset) { dns_rdataset_t rdataset; isc_result_t result; dns_rdataset_init(&rdataset); dns_rdataset_clone(nsecset, &rdataset); for (result = dns_rdataset_first(&rdataset); result == ISC_R_SUCCESS; result = dns_rdataset_next(&rdataset)) { dns_rdata_t rdata = DNS_RDATA_INIT; dns_rdataset_current(&rdataset, &rdata); if (dns_nsec_typepresent(&rdata, dns_rdatatype_soa) && (!dns_nsec_typepresent(&rdata, dns_rdatatype_dnskey) || !dns_nsec_typepresent(&rdata, dns_rdatatype_ns))) { dns_rdataset_disassociate(&rdataset); return false; } } dns_rdataset_disassociate(&rdataset); return true; } /* * Look for NSEC next name that starts with the label '\000'. */ static bool has_000_label(dns_rdataset_t *nsecset) { dns_rdataset_t rdataset; isc_result_t result; dns_rdataset_init(&rdataset); dns_rdataset_clone(nsecset, &rdataset); for (result = dns_rdataset_first(&rdataset); result == ISC_R_SUCCESS; result = dns_rdataset_next(&rdataset)) { dns_rdata_t rdata = DNS_RDATA_INIT; dns_rdataset_current(&rdataset, &rdata); if (rdata.length > 1 && rdata.data[0] == 1 && rdata.data[1] == 0) { dns_rdataset_disassociate(&rdataset); return true; } } dns_rdataset_disassociate(&rdataset); return false; } /* * The validator has finished. */ static void validated(void *arg) { dns_validator_t *val = (dns_validator_t *)arg; dns_adbaddrinfo_t *addrinfo = NULL; dns_dbnode_t *node = NULL; dns_dbnode_t *nsnode = NULL; dns_fetchresponse_t *hresp = NULL; dns_name_t *name = NULL; dns_rdataset_t *ardataset = NULL; dns_rdataset_t *asigrdataset = NULL; dns_rdataset_t *rdataset = NULL; dns_rdataset_t *sigrdataset = NULL; dns_resolver_t *res = NULL; dns_valarg_t *valarg = NULL; fetchctx_t *fctx = NULL; bool chaining; bool negative; bool sentresponse; isc_result_t eresult = ISC_R_SUCCESS; isc_result_t result = ISC_R_SUCCESS; isc_stdtime_t now; uint32_t ttl; unsigned int options; dns_fixedname_t fwild; dns_name_t *wild = NULL; dns_message_t *message = NULL; bool done = false; valarg = val->arg; REQUIRE(VALID_FCTX(valarg->fctx)); REQUIRE(!ISC_LIST_EMPTY(valarg->fctx->validators)); fctx = valarg->fctx; valarg->fctx = NULL; REQUIRE(fctx->tid == isc_tid()); FCTXTRACE("received validation completion event"); res = fctx->res; addrinfo = valarg->addrinfo; message = val->message; fctx->vresult = val->result; LOCK(&fctx->lock); ISC_LIST_UNLINK(fctx->validators, val, link); fctx->validator = NULL; UNLOCK(&fctx->lock); /* * Destroy the validator early so that we can * destroy the fctx if necessary. Save the wildcard name. */ if (val->proofs[DNS_VALIDATOR_NOQNAMEPROOF] != NULL) { wild = dns_fixedname_initname(&fwild); dns_name_copy(dns_fixedname_name(&val->wild), wild); } isc_mem_put(fctx->mctx, valarg, sizeof(*valarg)); negative = (val->rdataset == NULL); LOCK(&fctx->lock); sentresponse = ((fctx->options & DNS_FETCHOPT_NOVALIDATE) != 0); /* * If shutting down, ignore the results. Check to see if we're * done waiting for validator completions and ADB pending * events; if so, destroy the fctx. */ if (SHUTTINGDOWN(fctx) && !sentresponse) { UNLOCK(&fctx->lock); goto cleanup_fetchctx; } now = isc_stdtime_now(); /* * If chaining, we need to make sure that the right result code * is returned, and that the rdatasets are bound. */ if (val->result == ISC_R_SUCCESS && !negative && val->rdataset != NULL && CHAINING(val->rdataset)) { if (val->rdataset->type == dns_rdatatype_cname) { eresult = DNS_R_CNAME; } else { INSIST(val->rdataset->type == dns_rdatatype_dname); eresult = DNS_R_DNAME; } chaining = true; } else { chaining = false; } /* * Either we're not shutting down, or we are shutting down but * want to cache the result anyway (if this was a validation * started by a query with cd set) */ hresp = ISC_LIST_HEAD(fctx->resps); if (hresp != NULL) { if (!negative && !chaining && (fctx->type == dns_rdatatype_any || fctx->type == dns_rdatatype_rrsig || fctx->type == dns_rdatatype_sig)) { /* * Don't bind rdatasets; the caller * will iterate the node. */ } else { ardataset = hresp->rdataset; asigrdataset = hresp->sigrdataset; } } if (val->result != ISC_R_SUCCESS) { FCTXTRACE("validation failed"); inc_stats(res, dns_resstatscounter_valfail); fctx->valfail++; fctx->vresult = val->result; if (fctx->vresult != DNS_R_BROKENCHAIN) { result = ISC_R_NOTFOUND; if (val->rdataset != NULL) { result = dns_db_findnode(fctx->cache, val->name, false, &node); } if (result == ISC_R_SUCCESS) { (void)dns_db_deleterdataset(fctx->cache, node, NULL, val->type, 0); } if (result == ISC_R_SUCCESS && val->sigrdataset != NULL) { (void)dns_db_deleterdataset( fctx->cache, node, NULL, dns_rdatatype_rrsig, val->type); } if (result == ISC_R_SUCCESS) { dns_db_detachnode(fctx->cache, &node); } } if (fctx->vresult == DNS_R_BROKENCHAIN && !negative) { /* * Cache the data as pending for later * validation. */ result = ISC_R_NOTFOUND; if (val->rdataset != NULL) { result = dns_db_findnode(fctx->cache, val->name, true, &node); } if (result == ISC_R_SUCCESS) { (void)dns_db_addrdataset( fctx->cache, node, NULL, now, val->rdataset, 0, NULL); } if (result == ISC_R_SUCCESS && val->sigrdataset != NULL) { (void)dns_db_addrdataset( fctx->cache, node, NULL, now, val->sigrdataset, 0, NULL); } if (result == ISC_R_SUCCESS) { dns_db_detachnode(fctx->cache, &node); } } result = fctx->vresult; add_bad(fctx, message, addrinfo, result, badns_validation); UNLOCK(&fctx->lock); INSIST(fctx->validator == NULL); fctx->validator = ISC_LIST_HEAD(fctx->validators); if (fctx->validator != NULL) { dns_validator_send(fctx->validator); goto cleanup_fetchctx; } else if (sentresponse) { done = true; goto cleanup_fetchctx; } else if (result == DNS_R_BROKENCHAIN) { done = true; goto cleanup_fetchctx; } else { fctx_try(fctx, true); goto cleanup_fetchctx; } UNREACHABLE(); } if (negative) { dns_rdatatype_t covers; FCTXTRACE("nonexistence validation OK"); inc_stats(res, dns_resstatscounter_valnegsuccess); /* * Cache DS NXDOMAIN separately to other types. */ if (message->rcode == dns_rcode_nxdomain && fctx->type != dns_rdatatype_ds) { covers = dns_rdatatype_any; } else { covers = fctx->type; } /* * Don't report qname minimisation NXDOMAIN errors * when the result is NXDOMAIN except we have already * confirmed a higher error. */ if (!fctx->force_qmin_warning && message->rcode == dns_rcode_nxdomain && (fctx->qmin_warning == DNS_R_NXDOMAIN || fctx->qmin_warning == DNS_R_NCACHENXDOMAIN)) { fctx->qmin_warning = ISC_R_SUCCESS; } result = dns_db_findnode(fctx->cache, val->name, true, &node); if (result != ISC_R_SUCCESS) { /* fctx->lock unlocked in noanswer_response */ goto noanswer_response; } /* * If we are asking for a SOA record set the cache time * to zero to facilitate locating the containing zone of * a arbitrary zone. */ ttl = res->view->maxncachettl; if (fctx->type == dns_rdatatype_soa && covers == dns_rdatatype_any && res->zero_no_soa_ttl) { ttl = 0; } result = ncache_adderesult(message, fctx->cache, node, covers, now, fctx->res->view->minncachettl, ttl, val->optout, val->secure, ardataset, &eresult); if (result != ISC_R_SUCCESS) { goto noanswer_response; } goto answer_response; } else { inc_stats(res, dns_resstatscounter_valsuccess); } FCTXTRACE("validation OK"); if (val->proofs[DNS_VALIDATOR_NOQNAMEPROOF] != NULL) { result = dns_rdataset_addnoqname( val->rdataset, val->proofs[DNS_VALIDATOR_NOQNAMEPROOF]); RUNTIME_CHECK(result == ISC_R_SUCCESS); INSIST(val->sigrdataset != NULL); val->sigrdataset->ttl = val->rdataset->ttl; if (val->proofs[DNS_VALIDATOR_CLOSESTENCLOSER] != NULL) { result = dns_rdataset_addclosest( val->rdataset, val->proofs[DNS_VALIDATOR_CLOSESTENCLOSER]); RUNTIME_CHECK(result == ISC_R_SUCCESS); } } else if (val->rdataset->trust == dns_trust_answer && val->rdataset->type != dns_rdatatype_rrsig) { isc_result_t tresult; dns_name_t *noqname = NULL; tresult = findnoqname(fctx, message, val->name, val->rdataset->type, &noqname); if (tresult == ISC_R_SUCCESS && noqname != NULL) { tresult = dns_rdataset_addnoqname(val->rdataset, noqname); RUNTIME_CHECK(tresult == ISC_R_SUCCESS); } } /* * The data was already cached as pending data. * Re-cache it as secure and bind the cached * rdatasets to the first event on the fetch * event list. */ result = dns_db_findnode(fctx->cache, val->name, true, &node); if (result != ISC_R_SUCCESS) { goto noanswer_response; } options = 0; if ((fctx->options & DNS_FETCHOPT_PREFETCH) != 0) { options = DNS_DBADD_PREFETCH; } result = dns_db_addrdataset(fctx->cache, node, NULL, now, val->rdataset, options, ardataset); if (result != ISC_R_SUCCESS && result != DNS_R_UNCHANGED) { goto noanswer_response; } if (ardataset != NULL && NEGATIVE(ardataset)) { if (NXDOMAIN(ardataset)) { eresult = DNS_R_NCACHENXDOMAIN; } else { eresult = DNS_R_NCACHENXRRSET; } } else if (val->sigrdataset != NULL) { result = dns_db_addrdataset(fctx->cache, node, NULL, now, val->sigrdataset, options, asigrdataset); if (result != ISC_R_SUCCESS && result != DNS_R_UNCHANGED) { goto noanswer_response; } } if (sentresponse) { /* * If we only deferred the destroy because we wanted to * cache the data, destroy now. */ dns_db_detachnode(fctx->cache, &node); if (SHUTTINGDOWN(fctx)) { maybe_cancel_validators(fctx); } UNLOCK(&fctx->lock); goto cleanup_fetchctx; } if (!ISC_LIST_EMPTY(fctx->validators)) { INSIST(!negative); INSIST(fctx->type == dns_rdatatype_any || fctx->type == dns_rdatatype_rrsig || fctx->type == dns_rdatatype_sig); /* * Don't send a response yet - we have * more rdatasets that still need to * be validated. */ dns_db_detachnode(fctx->cache, &node); UNLOCK(&fctx->lock); dns_validator_send(ISC_LIST_HEAD(fctx->validators)); goto cleanup_fetchctx; } answer_response: /* * Cache any SOA/NS/NSEC records that happened to be validated. */ result = dns_message_firstname(message, DNS_SECTION_AUTHORITY); while (result == ISC_R_SUCCESS) { name = NULL; dns_message_currentname(message, DNS_SECTION_AUTHORITY, &name); for (rdataset = ISC_LIST_HEAD(name->list); rdataset != NULL; rdataset = ISC_LIST_NEXT(rdataset, link)) { if ((rdataset->type != dns_rdatatype_ns && rdataset->type != dns_rdatatype_soa && rdataset->type != dns_rdatatype_nsec) || rdataset->trust != dns_trust_secure) { continue; } for (sigrdataset = ISC_LIST_HEAD(name->list); sigrdataset != NULL; sigrdataset = ISC_LIST_NEXT(sigrdataset, link)) { if (sigrdataset->type != dns_rdatatype_rrsig || sigrdataset->covers != rdataset->type) { continue; } break; } if (sigrdataset == NULL || sigrdataset->trust != dns_trust_secure) { continue; } /* * Don't cache NSEC if missing NSEC or RRSIG types. */ if (rdataset->type == dns_rdatatype_nsec && !dns_nsec_requiredtypespresent(rdataset)) { continue; } /* * Don't cache "white lies" but do cache * "black lies". */ if (rdataset->type == dns_rdatatype_nsec && !dns_name_equal(fctx->name, name) && is_minimal_nsec(rdataset)) { continue; } /* * Check SOA and DNSKEY consistency. */ if (rdataset->type == dns_rdatatype_nsec && !check_soa_and_dnskey(rdataset)) { continue; } /* * Look for \000 label in next name. */ if (rdataset->type == dns_rdatatype_nsec && has_000_label(rdataset)) { continue; } result = dns_db_findnode(fctx->cache, name, true, &nsnode); if (result != ISC_R_SUCCESS) { continue; } result = dns_db_addrdataset(fctx->cache, nsnode, NULL, now, rdataset, 0, NULL); if (result == ISC_R_SUCCESS) { result = dns_db_addrdataset( fctx->cache, nsnode, NULL, now, sigrdataset, 0, NULL); } dns_db_detachnode(fctx->cache, &nsnode); if (result != ISC_R_SUCCESS) { continue; } } result = dns_message_nextname(message, DNS_SECTION_AUTHORITY); } /* * Add the wild card entry. */ if (val->proofs[DNS_VALIDATOR_NOQNAMEPROOF] != NULL && val->rdataset != NULL && dns_rdataset_isassociated(val->rdataset) && val->rdataset->trust == dns_trust_secure && val->sigrdataset != NULL && dns_rdataset_isassociated(val->sigrdataset) && val->sigrdataset->trust == dns_trust_secure && wild != NULL) { dns_dbnode_t *wnode = NULL; result = dns_db_findnode(fctx->cache, wild, true, &wnode); if (result == ISC_R_SUCCESS) { result = dns_db_addrdataset(fctx->cache, wnode, NULL, now, val->rdataset, 0, NULL); } if (result == ISC_R_SUCCESS) { (void)dns_db_addrdataset(fctx->cache, wnode, NULL, now, val->sigrdataset, 0, NULL); } if (wnode != NULL) { dns_db_detachnode(fctx->cache, &wnode); } } result = ISC_R_SUCCESS; /* * Respond with an answer, positive or negative, * as opposed to an error. 'node' must be non-NULL. */ FCTX_ATTR_SET(fctx, FCTX_ATTR_HAVEANSWER); if (hresp != NULL) { /* * Negative results must be indicated in val->result. */ INSIST(hresp->rdataset != NULL); if (dns_rdataset_isassociated(hresp->rdataset) && NEGATIVE(hresp->rdataset)) { INSIST(eresult == DNS_R_NCACHENXDOMAIN || eresult == DNS_R_NCACHENXRRSET); } hresp->result = eresult; dns_name_copy(val->name, hresp->foundname); dns_db_attach(fctx->cache, &hresp->db); dns_db_transfernode(fctx->cache, &node, &hresp->node); clone_results(fctx); } noanswer_response: if (node != NULL) { dns_db_detachnode(fctx->cache, &node); } UNLOCK(&fctx->lock); done = true; cleanup_fetchctx: if (done) { fctx_done_unref(fctx, result); } /* * val->name points to name on a message on one of the * queries on the fetch context so the name has to be * released first with a dns_validator_shutdown() call. */ dns_validator_shutdown(val); dns_validator_detach(&val); fetchctx_detach(&fctx); INSIST(node == NULL); } static void fctx_log(void *arg, int level, const char *fmt, ...) { char msgbuf[2048]; va_list args; fetchctx_t *fctx = arg; va_start(args, fmt); vsnprintf(msgbuf, sizeof(msgbuf), fmt, args); va_end(args); isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER, level, "fctx %p(%s): %s", fctx, fctx->info, msgbuf); } static isc_result_t findnoqname(fetchctx_t *fctx, dns_message_t *message, dns_name_t *name, dns_rdatatype_t type, dns_name_t **noqnamep) { dns_rdataset_t *nrdataset, *next, *sigrdataset; dns_rdata_rrsig_t rrsig; isc_result_t result; unsigned int labels; dns_section_t section; dns_name_t *zonename; dns_fixedname_t fzonename; dns_name_t *closest; dns_fixedname_t fclosest; dns_name_t *nearest; dns_fixedname_t fnearest; dns_rdatatype_t found = dns_rdatatype_none; dns_name_t *noqname = NULL; FCTXTRACE("findnoqname"); REQUIRE(noqnamep != NULL && *noqnamep == NULL); /* * Find the SIG for this rdataset, if we have it. */ for (sigrdataset = ISC_LIST_HEAD(name->list); sigrdataset != NULL; sigrdataset = ISC_LIST_NEXT(sigrdataset, link)) { if (sigrdataset->type == dns_rdatatype_rrsig && sigrdataset->covers == type) { break; } } if (sigrdataset == NULL) { return ISC_R_NOTFOUND; } labels = dns_name_countlabels(name); for (result = dns_rdataset_first(sigrdataset); result == ISC_R_SUCCESS; result = dns_rdataset_next(sigrdataset)) { dns_rdata_t rdata = DNS_RDATA_INIT; dns_rdataset_current(sigrdataset, &rdata); result = dns_rdata_tostruct(&rdata, &rrsig, NULL); RUNTIME_CHECK(result == ISC_R_SUCCESS); /* Wildcard has rrsig.labels < labels - 1. */ if (rrsig.labels + 1U >= labels) { continue; } break; } if (result == ISC_R_NOMORE) { return ISC_R_NOTFOUND; } if (result != ISC_R_SUCCESS) { return result; } zonename = dns_fixedname_initname(&fzonename); closest = dns_fixedname_initname(&fclosest); nearest = dns_fixedname_initname(&fnearest); #define NXND(x) ((x) == ISC_R_SUCCESS) section = DNS_SECTION_AUTHORITY; for (result = dns_message_firstname(message, section); result == ISC_R_SUCCESS; result = dns_message_nextname(message, section)) { dns_name_t *nsec = NULL; dns_message_currentname(message, section, &nsec); for (nrdataset = ISC_LIST_HEAD(nsec->list); nrdataset != NULL; nrdataset = next) { bool data = false, exists = false; bool optout = false, unknown = false; bool setclosest = false; bool setnearest = false; next = ISC_LIST_NEXT(nrdataset, link); if (nrdataset->type != dns_rdatatype_nsec && nrdataset->type != dns_rdatatype_nsec3) { continue; } if (nrdataset->type == dns_rdatatype_nsec && NXND(dns_nsec_noexistnodata( type, name, nsec, nrdataset, &exists, &data, NULL, fctx_log, fctx))) { if (!exists) { noqname = nsec; found = dns_rdatatype_nsec; } } if (nrdataset->type == dns_rdatatype_nsec3 && NXND(dns_nsec3_noexistnodata( type, name, nsec, nrdataset, zonename, &exists, &data, &optout, &unknown, &setclosest, &setnearest, closest, nearest, fctx_log, fctx))) { if (!exists && setnearest) { noqname = nsec; found = dns_rdatatype_nsec3; } } } } if (result == ISC_R_NOMORE) { result = ISC_R_SUCCESS; } if (noqname != NULL) { for (sigrdataset = ISC_LIST_HEAD(noqname->list); sigrdataset != NULL; sigrdataset = ISC_LIST_NEXT(sigrdataset, link)) { if (sigrdataset->type == dns_rdatatype_rrsig && sigrdataset->covers == found) { break; } } if (sigrdataset != NULL) { *noqnamep = noqname; } } return result; } static isc_result_t cache_name(fetchctx_t *fctx, dns_name_t *name, dns_message_t *message, dns_adbaddrinfo_t *addrinfo, isc_stdtime_t now) { dns_rdataset_t *rdataset = NULL, *sigrdataset = NULL; dns_rdataset_t *addedrdataset = NULL; dns_rdataset_t *ardataset = NULL, *asigrdataset = NULL; dns_rdataset_t *valrdataset = NULL, *valsigrdataset = NULL; dns_dbnode_t *node = NULL, **anodep = NULL; dns_db_t **adbp = NULL; dns_resolver_t *res = fctx->res; bool need_validation = false; bool secure_domain = false; bool have_answer = false; isc_result_t result, eresult = ISC_R_SUCCESS; dns_fetchresponse_t *resp = NULL; unsigned int options; bool fail; unsigned int valoptions = 0; bool checknta = true; FCTXTRACE("cache_name"); /* * The appropriate bucket lock must be held. */ /* * Is DNSSEC validation required for this name? */ if ((fctx->options & DNS_FETCHOPT_NONTA) != 0) { valoptions |= DNS_VALIDATOR_NONTA; checknta = false; } if (res->view->enablevalidation) { result = issecuredomain(res->view, name, fctx->type, now, checknta, NULL, &secure_domain); if (result != ISC_R_SUCCESS) { return result; } } if ((fctx->options & DNS_FETCHOPT_NOCDFLAG) != 0) { valoptions |= DNS_VALIDATOR_NOCDFLAG; } if ((fctx->options & DNS_FETCHOPT_NOVALIDATE) != 0) { need_validation = false; } else { need_validation = secure_domain; } if (name->attributes.answer && !need_validation) { have_answer = true; resp = ISC_LIST_HEAD(fctx->resps); if (resp != NULL) { adbp = &resp->db; dns_name_copy(name, resp->foundname); anodep = &resp->node; /* * If this is an ANY, SIG or RRSIG query, we're * not going to return any rdatasets, unless we * encountered a CNAME or DNAME as "the answer". * In this case, we're going to return * DNS_R_CNAME or DNS_R_DNAME and we must set up * the rdatasets. */ if ((fctx->type != dns_rdatatype_any && fctx->type != dns_rdatatype_rrsig && fctx->type != dns_rdatatype_sig) || name->attributes.chaining) { ardataset = resp->rdataset; asigrdataset = resp->sigrdataset; } } } /* * Find or create the cache node. */ result = dns_db_findnode(fctx->cache, name, true, &node); if (result != ISC_R_SUCCESS) { return result; } /* * Cache or validate each cacheable rdataset. */ fail = ((fctx->res->options & DNS_RESOLVER_CHECKNAMESFAIL) != 0); for (rdataset = ISC_LIST_HEAD(name->list); rdataset != NULL; rdataset = ISC_LIST_NEXT(rdataset, link)) { if (!CACHE(rdataset)) { continue; } if (CHECKNAMES(rdataset)) { char namebuf[DNS_NAME_FORMATSIZE]; char typebuf[DNS_RDATATYPE_FORMATSIZE]; char classbuf[DNS_RDATATYPE_FORMATSIZE]; dns_name_format(name, namebuf, sizeof(namebuf)); dns_rdatatype_format(rdataset->type, typebuf, sizeof(typebuf)); dns_rdataclass_format(rdataset->rdclass, classbuf, sizeof(classbuf)); isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER, ISC_LOG_NOTICE, "check-names %s %s/%s/%s", fail ? "failure" : "warning", namebuf, typebuf, classbuf); if (fail) { if (ANSWER(rdataset)) { dns_db_detachnode(fctx->cache, &node); return DNS_R_BADNAME; } continue; } } /* * Enforce the configure maximum cache TTL. */ if (rdataset->ttl > res->view->maxcachettl) { rdataset->ttl = res->view->maxcachettl; } /* * Enforce configured minimum cache TTL. */ if (rdataset->ttl < res->view->mincachettl) { rdataset->ttl = res->view->mincachettl; } /* * Mark the rdataset as being prefetch eligible. */ if (rdataset->ttl >= fctx->res->view->prefetch_eligible) { rdataset->attributes |= DNS_RDATASETATTR_PREFETCH; } /* * Find the SIG for this rdataset, if we have it. */ for (sigrdataset = ISC_LIST_HEAD(name->list); sigrdataset != NULL; sigrdataset = ISC_LIST_NEXT(sigrdataset, link)) { if (sigrdataset->type == dns_rdatatype_rrsig && sigrdataset->covers == rdataset->type) { break; } } /* * If this RRset is in a secure domain, is in bailiwick, * and is not glue, attempt DNSSEC validation. (We do * not attempt to validate glue or out-of-bailiwick * data--even though there might be some performance * benefit to doing so--because it makes it simpler and * safer to ensure that records from a secure domain are * only cached if validated within the context of a * query to the domain that owns them.) */ if (secure_domain && rdataset->trust != dns_trust_glue && !EXTERNAL(rdataset)) { dns_trust_t trust; /* * RRSIGs are validated as part of validating * the type they cover. */ if (rdataset->type == dns_rdatatype_rrsig) { continue; } if (sigrdataset == NULL && need_validation && !ANSWER(rdataset)) { /* * Ignore unrelated non-answer * rdatasets that are missing * signatures. */ continue; } /* * Normalize the rdataset and sigrdataset TTLs. */ if (sigrdataset != NULL) { rdataset->ttl = ISC_MIN(rdataset->ttl, sigrdataset->ttl); sigrdataset->ttl = rdataset->ttl; } /* * Mark the rdataset as being prefetch eligible. */ if (rdataset->ttl >= fctx->res->view->prefetch_eligible) { rdataset->attributes |= DNS_RDATASETATTR_PREFETCH; } /* * Cache this rdataset/sigrdataset pair as * pending data. Track whether it was * additional or not. If this was a priming * query, additional should be cached as glue. */ if (rdataset->trust == dns_trust_additional) { trust = dns_trust_pending_additional; } else { trust = dns_trust_pending_answer; } rdataset->trust = trust; if (sigrdataset != NULL) { sigrdataset->trust = trust; } if (!need_validation || !ANSWER(rdataset)) { options = 0; if (ANSWER(rdataset) && rdataset->type != dns_rdatatype_rrsig) { isc_result_t tresult; dns_name_t *noqname = NULL; tresult = findnoqname( fctx, message, name, rdataset->type, &noqname); if (tresult == ISC_R_SUCCESS && noqname != NULL) { (void)dns_rdataset_addnoqname( rdataset, noqname); } } if ((fctx->options & DNS_FETCHOPT_PREFETCH) != 0) { options = DNS_DBADD_PREFETCH; } if ((fctx->options & DNS_FETCHOPT_NOCACHED) != 0) { options |= DNS_DBADD_FORCE; } addedrdataset = ardataset; result = dns_db_addrdataset( fctx->cache, node, NULL, now, rdataset, options, addedrdataset); if (result == DNS_R_UNCHANGED) { result = ISC_R_SUCCESS; if (!need_validation && ardataset != NULL && NEGATIVE(ardataset)) { /* * The answer in the * cache is better than * the answer we found, * and is a negative * cache entry, so we * must set eresult * appropriately. */ if (NXDOMAIN(ardataset)) { eresult = DNS_R_NCACHENXDOMAIN; } else { eresult = DNS_R_NCACHENXRRSET; } /* * We have a negative * response from the * cache so don't * attempt to add the * RRSIG rrset. */ continue; } } if (result != ISC_R_SUCCESS) { break; } if (sigrdataset != NULL) { addedrdataset = asigrdataset; result = dns_db_addrdataset( fctx->cache, node, NULL, now, sigrdataset, options, addedrdataset); if (result == DNS_R_UNCHANGED) { result = ISC_R_SUCCESS; } if (result != ISC_R_SUCCESS) { break; } } else if (!ANSWER(rdataset)) { continue; } } if (ANSWER(rdataset) && need_validation) { if (fctx->type != dns_rdatatype_any && fctx->type != dns_rdatatype_rrsig && fctx->type != dns_rdatatype_sig) { /* * This is The Answer. We will * validate it, but first we * cache the rest of the * response - it may contain * useful keys. */ INSIST(valrdataset == NULL && valsigrdataset == NULL); valrdataset = rdataset; valsigrdataset = sigrdataset; } else { /* * This is one of (potentially) * multiple answers to an ANY * or SIG query. To keep things * simple, we just start the * validator right away rather * than caching first and * having to remember which * rdatasets needed validation. */ result = valcreate( fctx, message, addrinfo, name, rdataset->type, rdataset, sigrdataset, valoptions); } } else if (CHAINING(rdataset)) { if (rdataset->type == dns_rdatatype_cname) { eresult = DNS_R_CNAME; } else { INSIST(rdataset->type == dns_rdatatype_dname); eresult = DNS_R_DNAME; } } } else if (!EXTERNAL(rdataset)) { /* * It's OK to cache this rdataset now. */ if (ANSWER(rdataset)) { addedrdataset = ardataset; } else if (ANSWERSIG(rdataset)) { addedrdataset = asigrdataset; } else { addedrdataset = NULL; } if (CHAINING(rdataset)) { if (rdataset->type == dns_rdatatype_cname) { eresult = DNS_R_CNAME; } else { INSIST(rdataset->type == dns_rdatatype_dname); eresult = DNS_R_DNAME; } } if (rdataset->trust == dns_trust_glue && (rdataset->type == dns_rdatatype_ns || (rdataset->type == dns_rdatatype_rrsig && rdataset->covers == dns_rdatatype_ns))) { /* * If the trust level is * 'dns_trust_glue' then we are adding * data from a referral we got while * executing the search algorithm. New * referral data always takes precedence * over the existing cache contents. */ options = DNS_DBADD_FORCE; } else if ((fctx->options & DNS_FETCHOPT_PREFETCH) != 0) { options = DNS_DBADD_PREFETCH; } else { options = 0; } if (ANSWER(rdataset) && rdataset->type != dns_rdatatype_rrsig) { isc_result_t tresult; dns_name_t *noqname = NULL; tresult = findnoqname(fctx, message, name, rdataset->type, &noqname); if (tresult == ISC_R_SUCCESS && noqname != NULL) { (void)dns_rdataset_addnoqname(rdataset, noqname); } } /* * Now we can add the rdataset. */ result = dns_db_addrdataset(fctx->cache, node, NULL, now, rdataset, options, addedrdataset); if (result == DNS_R_UNCHANGED) { if (ANSWER(rdataset) && ardataset != NULL && NEGATIVE(ardataset)) { /* * The answer in the cache is * better than the answer we * found, and is a negative * cache entry, so we must set * eresult appropriately. */ if (NXDOMAIN(ardataset)) { eresult = DNS_R_NCACHENXDOMAIN; } else { eresult = DNS_R_NCACHENXRRSET; } } result = ISC_R_SUCCESS; } else if (result != ISC_R_SUCCESS) { break; } } } if (valrdataset != NULL) { dns_rdatatype_t vtype = fctx->type; if (CHAINING(valrdataset)) { if (valrdataset->type == dns_rdatatype_cname) { vtype = dns_rdatatype_cname; } else { vtype = dns_rdatatype_dname; } } result = valcreate(fctx, message, addrinfo, name, vtype, valrdataset, valsigrdataset, valoptions); } if (result == ISC_R_SUCCESS && have_answer) { FCTX_ATTR_SET(fctx, FCTX_ATTR_HAVEANSWER); if (resp != NULL) { /* * Negative results must be indicated in * resp->result. */ if (dns_rdataset_isassociated(resp->rdataset) && NEGATIVE(resp->rdataset)) { INSIST(eresult == DNS_R_NCACHENXDOMAIN || eresult == DNS_R_NCACHENXRRSET); } resp->result = eresult; if (adbp != NULL && *adbp != NULL) { if (anodep != NULL && *anodep != NULL) { dns_db_detachnode(*adbp, anodep); } dns_db_detach(adbp); } dns_db_attach(fctx->cache, adbp); dns_db_transfernode(fctx->cache, &node, anodep); clone_results(fctx); } } if (node != NULL) { dns_db_detachnode(fctx->cache, &node); } return result; } static isc_result_t cache_message(fetchctx_t *fctx, dns_message_t *message, dns_adbaddrinfo_t *addrinfo, isc_stdtime_t now) { isc_result_t result; dns_section_t section; dns_name_t *name; FCTXTRACE("cache_message"); FCTX_ATTR_CLR(fctx, FCTX_ATTR_WANTCACHE); LOCK(&fctx->lock); for (section = DNS_SECTION_ANSWER; section <= DNS_SECTION_ADDITIONAL; section++) { result = dns_message_firstname(message, section); while (result == ISC_R_SUCCESS) { name = NULL; dns_message_currentname(message, section, &name); if (name->attributes.cache) { result = cache_name(fctx, name, message, addrinfo, now); if (result != ISC_R_SUCCESS) { break; } } result = dns_message_nextname(message, section); } if (result != ISC_R_NOMORE) { break; } } if (result == ISC_R_NOMORE) { result = ISC_R_SUCCESS; } UNLOCK(&fctx->lock); return result; } /* * Do what dns_ncache_addoptout() does, and then compute an appropriate * eresult. */ static isc_result_t ncache_adderesult(dns_message_t *message, dns_db_t *cache, dns_dbnode_t *node, dns_rdatatype_t covers, isc_stdtime_t now, dns_ttl_t minttl, dns_ttl_t maxttl, bool optout, bool secure, dns_rdataset_t *ardataset, isc_result_t *eresultp) { isc_result_t result; dns_rdataset_t rdataset; if (ardataset == NULL) { dns_rdataset_init(&rdataset); ardataset = &rdataset; } if (secure) { result = dns_ncache_addoptout(message, cache, node, covers, now, minttl, maxttl, optout, ardataset); } else { result = dns_ncache_add(message, cache, node, covers, now, minttl, maxttl, ardataset); } if (result == DNS_R_UNCHANGED || result == ISC_R_SUCCESS) { /* * If the cache now contains a negative entry and we * care about whether it is DNS_R_NCACHENXDOMAIN or * DNS_R_NCACHENXRRSET then extract it. */ if (NEGATIVE(ardataset)) { /* * The cache data is a negative cache entry. */ if (NXDOMAIN(ardataset)) { *eresultp = DNS_R_NCACHENXDOMAIN; } else { *eresultp = DNS_R_NCACHENXRRSET; } } else { /* * Either we don't care about the nature of the * cache rdataset (because no fetch is * interested in the outcome), or the cache * rdataset is not a negative cache entry. * Whichever case it is, we can return success. * * XXXRTH There's a CNAME/DNAME problem here. */ *eresultp = ISC_R_SUCCESS; } result = ISC_R_SUCCESS; } if (ardataset == &rdataset && dns_rdataset_isassociated(ardataset)) { dns_rdataset_disassociate(ardataset); } return result; } static isc_result_t ncache_message(fetchctx_t *fctx, dns_message_t *message, dns_adbaddrinfo_t *addrinfo, dns_rdatatype_t covers, isc_stdtime_t now) { isc_result_t result, eresult = ISC_R_SUCCESS; dns_name_t *name = fctx->name; dns_resolver_t *res = fctx->res; dns_db_t **adbp = NULL; dns_dbnode_t *node = NULL, **anodep = NULL; dns_rdataset_t *ardataset = NULL; bool need_validation = false, secure_domain = false; dns_fetchresponse_t *resp = NULL; uint32_t ttl; unsigned int valoptions = 0; bool checknta = true; FCTXTRACE("ncache_message"); FCTX_ATTR_CLR(fctx, FCTX_ATTR_WANTNCACHE); POST(need_validation); /* * XXXMPA remove when we follow cnames and adjust the setting * of FCTX_ATTR_WANTNCACHE in rctx_answer_none(). */ INSIST(message->counts[DNS_SECTION_ANSWER] == 0); /* * Is DNSSEC validation required for this name? */ if ((fctx->options & DNS_FETCHOPT_NONTA) != 0) { valoptions |= DNS_VALIDATOR_NONTA; checknta = false; } if (fctx->res->view->enablevalidation) { result = issecuredomain(res->view, name, fctx->type, now, checknta, NULL, &secure_domain); if (result != ISC_R_SUCCESS) { return result; } } if ((fctx->options & DNS_FETCHOPT_NOCDFLAG) != 0) { valoptions |= DNS_VALIDATOR_NOCDFLAG; } if ((fctx->options & DNS_FETCHOPT_NOVALIDATE) != 0) { need_validation = false; } else { need_validation = secure_domain; } if (secure_domain) { /* * Mark all rdatasets as pending. */ result = dns_message_firstname(message, DNS_SECTION_AUTHORITY); while (result == ISC_R_SUCCESS) { dns_rdataset_t *trdataset = NULL; dns_name_t *tname = NULL; dns_message_currentname(message, DNS_SECTION_AUTHORITY, &tname); for (trdataset = ISC_LIST_HEAD(tname->list); trdataset != NULL; trdataset = ISC_LIST_NEXT(trdataset, link)) { trdataset->trust = dns_trust_pending_answer; } result = dns_message_nextname(message, DNS_SECTION_AUTHORITY); } if (result != ISC_R_NOMORE) { return result; } } if (need_validation) { /* * Do negative response validation. */ result = valcreate(fctx, message, addrinfo, name, fctx->type, NULL, NULL, valoptions); /* * If validation is necessary, return now. Otherwise * continue to process the message, letting the * validation complete in its own good time. */ return result; } LOCK(&fctx->lock); if (!HAVE_ANSWER(fctx)) { resp = ISC_LIST_HEAD(fctx->resps); if (resp != NULL) { adbp = &resp->db; dns_name_copy(name, resp->foundname); anodep = &resp->node; ardataset = resp->rdataset; } } result = dns_db_findnode(fctx->cache, name, true, &node); if (result != ISC_R_SUCCESS) { goto unlock; } /* * Don't report qname minimisation NXDOMAIN errors * when the result is NXDOMAIN except we have already * confirmed a higher error. */ if (!fctx->force_qmin_warning && message->rcode == dns_rcode_nxdomain && (fctx->qmin_warning == DNS_R_NXDOMAIN || fctx->qmin_warning == DNS_R_NCACHENXDOMAIN)) { fctx->qmin_warning = ISC_R_SUCCESS; } /* * If we are asking for a SOA record set the cache time * to zero to facilitate locating the containing zone of * a arbitrary zone. */ ttl = fctx->res->view->maxncachettl; if (fctx->type == dns_rdatatype_soa && covers == dns_rdatatype_any && fctx->res->zero_no_soa_ttl) { ttl = 0; } result = ncache_adderesult(message, fctx->cache, node, covers, now, fctx->res->view->minncachettl, ttl, false, false, ardataset, &eresult); if (result != ISC_R_SUCCESS) { goto unlock; } if (!HAVE_ANSWER(fctx)) { FCTX_ATTR_SET(fctx, FCTX_ATTR_HAVEANSWER); if (resp != NULL) { resp->result = eresult; if (adbp != NULL && *adbp != NULL) { if (anodep != NULL && *anodep != NULL) { dns_db_detachnode(*adbp, anodep); } dns_db_detach(adbp); } dns_db_attach(fctx->cache, adbp); dns_db_transfernode(fctx->cache, &node, anodep); clone_results(fctx); } } unlock: UNLOCK(&fctx->lock); if (node != NULL) { dns_db_detachnode(fctx->cache, &node); } return result; } static void mark_related(dns_name_t *name, dns_rdataset_t *rdataset, bool external, bool gluing) { name->attributes.cache = true; if (gluing) { rdataset->trust = dns_trust_glue; /* * Glue with 0 TTL causes problems. We force the TTL to * 1 second to prevent this. */ if (rdataset->ttl == 0) { rdataset->ttl = 1; } } else { rdataset->trust = dns_trust_additional; } /* * Avoid infinite loops by only marking new rdatasets. */ if (!CACHE(rdataset)) { name->attributes.chase = true; rdataset->attributes |= DNS_RDATASETATTR_CHASE; } rdataset->attributes |= DNS_RDATASETATTR_CACHE; if (external) { rdataset->attributes |= DNS_RDATASETATTR_EXTERNAL; } } /* * Returns true if 'name' is external to the namespace for which * the server being queried can answer, either because it's not a * subdomain or because it's below a forward declaration or a * locally served zone. */ static inline bool name_external(const dns_name_t *name, dns_rdatatype_t type, fetchctx_t *fctx) { isc_result_t result; dns_forwarders_t *forwarders = NULL; dns_name_t *apex = NULL; dns_name_t suffix; dns_zone_t *zone = NULL; unsigned int labels; dns_namereln_t rel; apex = (ISDUALSTACK(fctx->addrinfo) || !ISFORWARDER(fctx->addrinfo)) ? fctx->domain : fctx->fwdname; /* * The name is outside the queried namespace. */ rel = dns_name_fullcompare(name, apex, &(int){ 0 }, &(unsigned int){ 0U }); if (rel != dns_namereln_subdomain && rel != dns_namereln_equal) { return true; } /* * If the record lives in the parent zone, adjust the name so we * look for the correct zone or forward clause. */ labels = dns_name_countlabels(name); if (dns_rdatatype_atparent(type) && labels > 1U) { dns_name_init(&suffix, NULL); dns_name_getlabelsequence(name, 1, labels - 1, &suffix); name = &suffix; } else if (rel == dns_namereln_equal) { /* If 'name' is 'apex', no further checking is needed. */ return false; } /* * If there is a locally served zone between 'apex' and 'name' * then don't cache. */ dns_ztfind_t options = DNS_ZTFIND_NOEXACT | DNS_ZTFIND_MIRROR; result = dns_view_findzone(fctx->res->view, name, options, &zone); if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH) { dns_name_t *zname = dns_zone_getorigin(zone); dns_namereln_t reln = dns_name_fullcompare( zname, apex, &(int){ 0 }, &(unsigned int){ 0U }); dns_zone_detach(&zone); if (reln == dns_namereln_subdomain) { return true; } } /* * Look for a forward declaration below 'name'. */ result = dns_fwdtable_find(fctx->res->view->fwdtable, name, &forwarders); if (ISFORWARDER(fctx->addrinfo)) { /* * See if the forwarder declaration is better. */ if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH) { bool better = !dns_name_equal(&forwarders->name, fctx->fwdname); dns_forwarders_detach(&forwarders); return better; } /* * If the lookup failed, the configuration must have * changed: play it safe and don't cache. */ return true; } else if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH) { /* * If 'name' is covered by a 'forward only' clause then we * can't cache this response. */ bool nocache = (forwarders->fwdpolicy == dns_fwdpolicy_only && !ISC_LIST_EMPTY(forwarders->fwdrs)); dns_forwarders_detach(&forwarders); return nocache; } return false; } static isc_result_t check_section(void *arg, const dns_name_t *addname, dns_rdatatype_t type, dns_rdataset_t *found, dns_section_t section) { respctx_t *rctx = arg; fetchctx_t *fctx = rctx->fctx; isc_result_t result; dns_name_t *name = NULL; dns_rdataset_t *rdataset = NULL; bool external; dns_rdatatype_t rtype; bool gluing; REQUIRE(VALID_FCTX(fctx)); #if CHECK_FOR_GLUE_IN_ANSWER if (section == DNS_SECTION_ANSWER && type != dns_rdatatype_a) { return ISC_R_SUCCESS; } #endif /* if CHECK_FOR_GLUE_IN_ANSWER */ gluing = (GLUING(fctx) || (fctx->type == dns_rdatatype_ns && dns_name_equal(fctx->name, dns_rootname))); result = dns_message_findname(rctx->query->rmessage, section, addname, dns_rdatatype_any, 0, &name, NULL); if (result == ISC_R_SUCCESS) { external = name_external(name, type, fctx); if (type == dns_rdatatype_a) { for (rdataset = ISC_LIST_HEAD(name->list); rdataset != NULL; rdataset = ISC_LIST_NEXT(rdataset, link)) { if (rdataset->type == dns_rdatatype_rrsig) { rtype = rdataset->covers; } else { rtype = rdataset->type; } if (rtype == dns_rdatatype_a || rtype == dns_rdatatype_aaaa) { mark_related(name, rdataset, external, gluing); } } } else { result = dns_message_findtype(name, type, 0, &rdataset); if (result == ISC_R_SUCCESS) { mark_related(name, rdataset, external, gluing); if (found != NULL) { dns_rdataset_clone(rdataset, found); } /* * Do we have its SIG too? */ rdataset = NULL; result = dns_message_findtype( name, dns_rdatatype_rrsig, type, &rdataset); if (result == ISC_R_SUCCESS) { mark_related(name, rdataset, external, gluing); } } } } return ISC_R_SUCCESS; } static isc_result_t check_related(void *arg, const dns_name_t *addname, dns_rdatatype_t type, dns_rdataset_t *found DNS__DB_FLARG) { return check_section(arg, addname, type, found, DNS_SECTION_ADDITIONAL); } #ifndef CHECK_FOR_GLUE_IN_ANSWER #define CHECK_FOR_GLUE_IN_ANSWER 0 #endif /* ifndef CHECK_FOR_GLUE_IN_ANSWER */ #if CHECK_FOR_GLUE_IN_ANSWER static isc_result_t check_answer(void *arg, const dns_name_t *addname, dns_rdatatype_t type, dns_rdataset_t *found) { return check_section(arg, addname, type, found, DNS_SECTION_ANSWER); } #endif /* if CHECK_FOR_GLUE_IN_ANSWER */ static bool is_answeraddress_allowed(dns_view_t *view, dns_name_t *name, dns_rdataset_t *rdataset) { isc_result_t result; dns_rdata_t rdata = DNS_RDATA_INIT; struct in_addr ina; struct in6_addr in6a; isc_netaddr_t netaddr; char addrbuf[ISC_NETADDR_FORMATSIZE]; char namebuf[DNS_NAME_FORMATSIZE]; char classbuf[64]; char typebuf[64]; int match; /* By default, we allow any addresses. */ if (view->denyansweracl == NULL) { return true; } /* * If the owner name matches one in the exclusion list, either * exactly or partially, allow it. */ if (dns_nametree_covered(view->answeracl_exclude, name, NULL, 0)) { return true; } /* * Otherwise, search the filter list for a match for each * address record. If a match is found, the address should be * filtered, so should the entire answer. */ for (result = dns_rdataset_first(rdataset); result == ISC_R_SUCCESS; result = dns_rdataset_next(rdataset)) { dns_rdata_reset(&rdata); dns_rdataset_current(rdataset, &rdata); if (rdataset->type == dns_rdatatype_a) { INSIST(rdata.length == sizeof(ina.s_addr)); memmove(&ina.s_addr, rdata.data, sizeof(ina.s_addr)); isc_netaddr_fromin(&netaddr, &ina); } else { INSIST(rdata.length == sizeof(in6a.s6_addr)); memmove(in6a.s6_addr, rdata.data, sizeof(in6a.s6_addr)); isc_netaddr_fromin6(&netaddr, &in6a); } result = dns_acl_match(&netaddr, NULL, view->denyansweracl, view->aclenv, &match, NULL); if (result == ISC_R_SUCCESS && match > 0) { isc_netaddr_format(&netaddr, addrbuf, sizeof(addrbuf)); dns_name_format(name, namebuf, sizeof(namebuf)); dns_rdatatype_format(rdataset->type, typebuf, sizeof(typebuf)); dns_rdataclass_format(rdataset->rdclass, classbuf, sizeof(classbuf)); isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER, ISC_LOG_NOTICE, "answer address %s denied for %s/%s/%s", addrbuf, namebuf, typebuf, classbuf); return false; } } return true; } static bool is_answertarget_allowed(fetchctx_t *fctx, dns_name_t *qname, dns_name_t *rname, dns_rdataset_t *rdataset, bool *chainingp) { isc_result_t result; dns_name_t *tname = NULL; dns_rdata_cname_t cname; dns_rdata_dname_t dname; dns_view_t *view = fctx->res->view; dns_rdata_t rdata = DNS_RDATA_INIT; unsigned int nlabels; dns_fixedname_t fixed; dns_name_t prefix; int order; REQUIRE(rdataset != NULL); REQUIRE(rdataset->type == dns_rdatatype_cname || rdataset->type == dns_rdatatype_dname); /* * By default, we allow any target name. * If newqname != NULL we also need to extract the newqname. */ if (chainingp == NULL && view->denyanswernames == NULL) { return true; } result = dns_rdataset_first(rdataset); RUNTIME_CHECK(result == ISC_R_SUCCESS); dns_rdataset_current(rdataset, &rdata); switch (rdataset->type) { case dns_rdatatype_cname: result = dns_rdata_tostruct(&rdata, &cname, NULL); RUNTIME_CHECK(result == ISC_R_SUCCESS); tname = &cname.cname; break; case dns_rdatatype_dname: if (dns_name_fullcompare(qname, rname, &order, &nlabels) != dns_namereln_subdomain) { return true; } result = dns_rdata_tostruct(&rdata, &dname, NULL); RUNTIME_CHECK(result == ISC_R_SUCCESS); dns_name_init(&prefix, NULL); tname = dns_fixedname_initname(&fixed); nlabels = dns_name_countlabels(rname); dns_name_split(qname, nlabels, &prefix, NULL); result = dns_name_concatenate(&prefix, &dname.dname, tname, NULL); if (result == DNS_R_NAMETOOLONG) { SET_IF_NOT_NULL(chainingp, true); return true; } RUNTIME_CHECK(result == ISC_R_SUCCESS); break; default: UNREACHABLE(); } SET_IF_NOT_NULL(chainingp, true); if (view->denyanswernames == NULL) { return true; } /* * If the owner name matches one in the exclusion list, either * exactly or partially, allow it. */ if (dns_nametree_covered(view->answernames_exclude, qname, NULL, 0)) { return true; } /* * If the target name is a subdomain of the search domain, allow * it. * * Note that if BIND is configured as a forwarding DNS server, * the search domain will always match the root domain ("."), so * we must also check whether forwarding is enabled so that * filters can be applied; see GL #1574. */ if (!fctx->forwarding && dns_name_issubdomain(tname, fctx->domain)) { return true; } /* * Otherwise, apply filters. */ if (dns_nametree_covered(view->denyanswernames, tname, NULL, 0)) { char qnamebuf[DNS_NAME_FORMATSIZE]; char tnamebuf[DNS_NAME_FORMATSIZE]; char classbuf[64]; char typebuf[64]; dns_name_format(qname, qnamebuf, sizeof(qnamebuf)); dns_name_format(tname, tnamebuf, sizeof(tnamebuf)); dns_rdatatype_format(rdataset->type, typebuf, sizeof(typebuf)); dns_rdataclass_format(view->rdclass, classbuf, sizeof(classbuf)); isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER, ISC_LOG_NOTICE, "%s target %s denied for %s/%s", typebuf, tnamebuf, qnamebuf, classbuf); return false; } return true; } static void trim_ns_ttl(fetchctx_t *fctx, dns_name_t *name, dns_rdataset_t *rdataset) { if (fctx->ns_ttl_ok && rdataset->ttl > fctx->ns_ttl) { char ns_namebuf[DNS_NAME_FORMATSIZE]; char namebuf[DNS_NAME_FORMATSIZE]; char tbuf[DNS_RDATATYPE_FORMATSIZE]; dns_name_format(name, ns_namebuf, sizeof(ns_namebuf)); dns_name_format(fctx->name, namebuf, sizeof(namebuf)); dns_rdatatype_format(fctx->type, tbuf, sizeof(tbuf)); isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER, ISC_LOG_DEBUG(10), "fctx %p: trimming ttl of %s/NS for %s/%s: " "%u -> %u", fctx, ns_namebuf, namebuf, tbuf, rdataset->ttl, fctx->ns_ttl); rdataset->ttl = fctx->ns_ttl; } } static bool validinanswer(dns_rdataset_t *rdataset, fetchctx_t *fctx) { if (rdataset->type == dns_rdatatype_nsec3) { /* * NSEC3 records are not allowed to * appear in the answer section. */ log_formerr(fctx, "NSEC3 in answer"); return false; } if (rdataset->type == dns_rdatatype_tkey) { /* * TKEY is not a valid record in a * response to any query we can make. */ log_formerr(fctx, "TKEY in answer"); return false; } if (rdataset->rdclass != fctx->res->rdclass) { log_formerr(fctx, "Mismatched class in answer"); return false; } return true; } #if DNS_RESOLVER_TRACE ISC_REFCOUNT_TRACE_IMPL(fetchctx, fctx_destroy); #else ISC_REFCOUNT_IMPL(fetchctx, fctx_destroy); #endif static uint32_t fctx_hash(fetchctx_t *fctx) { isc_hash32_t hash32; isc_hash32_init(&hash32); isc_hash32_hash(&hash32, fctx->name->ndata, fctx->name->length, false); isc_hash32_hash(&hash32, &fctx->options, sizeof(fctx->options), true); isc_hash32_hash(&hash32, &fctx->type, sizeof(fctx->type), true); return isc_hash32_finalize(&hash32); } static bool fctx_match(void *node, const void *key) { const fetchctx_t *fctx0 = node; const fetchctx_t *fctx1 = key; return fctx0->options == fctx1->options && fctx0->type == fctx1->type && dns_name_equal(fctx0->name, fctx1->name); } /* Must be fctx locked */ static void release_fctx(fetchctx_t *fctx) { isc_result_t result; dns_resolver_t *res = fctx->res; if (!fctx->hashed) { return; } RWLOCK(&res->fctxs_lock, isc_rwlocktype_write); result = isc_hashmap_delete(res->fctxs, fctx_hash(fctx), match_ptr, fctx); INSIST(result == ISC_R_SUCCESS); fctx->hashed = false; RWUNLOCK(&res->fctxs_lock, isc_rwlocktype_write); } static void resume_dslookup(void *arg) { dns_fetchresponse_t *resp = (dns_fetchresponse_t *)arg; fetchctx_t *fctx = resp->arg; isc_loop_t *loop = resp->loop; isc_result_t result; dns_resolver_t *res = NULL; dns_rdataset_t *frdataset = NULL, *nsrdataset = NULL; dns_rdataset_t nameservers; dns_fixedname_t fixed; dns_name_t *domain = NULL; unsigned int n; dns_fetch_t *fetch = NULL; REQUIRE(VALID_FCTX(fctx)); res = fctx->res; REQUIRE(fctx->tid == isc_tid()); FCTXTRACE("resume_dslookup"); if (resp->node != NULL) { dns_db_detachnode(resp->db, &resp->node); } if (resp->db != NULL) { dns_db_detach(&resp->db); } /* Preserve data from resp before freeing it. */ frdataset = resp->rdataset; /* a.k.a. fctx->nsrrset */ result = resp->result; isc_mem_putanddetach(&resp->mctx, resp, sizeof(*resp)); LOCK(&fctx->lock); if (SHUTTINGDOWN(fctx)) { result = ISC_R_SHUTTINGDOWN; } UNLOCK(&fctx->lock); fetch = fctx->nsfetch; fctx->nsfetch = NULL; FTRACE("resume_dslookup"); switch (result) { case ISC_R_SUCCESS: FCTXTRACE("resuming DS lookup"); if (dns_rdataset_isassociated(&fctx->nameservers)) { dns_rdataset_disassociate(&fctx->nameservers); } dns_rdataset_clone(frdataset, &fctx->nameservers); /* * Disassociate now the NS's are saved. */ if (dns_rdataset_isassociated(frdataset)) { dns_rdataset_disassociate(frdataset); } fctx->ns_ttl = fctx->nameservers.ttl; fctx->ns_ttl_ok = true; log_ns_ttl(fctx, "resume_dslookup"); fcount_decr(fctx); dns_name_copy(fctx->nsname, fctx->domain); result = fcount_incr(fctx, true); if (result != ISC_R_SUCCESS) { goto cleanup; } /* Try again. */ fctx_try(fctx, true); break; case ISC_R_SHUTTINGDOWN: case ISC_R_CANCELED: /* Don't try anymore. */ /* Can't be done in cleanup. */ if (dns_rdataset_isassociated(frdataset)) { dns_rdataset_disassociate(frdataset); } goto cleanup; default: /* * Disassociate for the next dns_resolver_createfetch call. */ if (dns_rdataset_isassociated(frdataset)) { dns_rdataset_disassociate(frdataset); } /* * If the chain of resume_dslookup() invocations managed to * chop off enough labels from the original DS owner name to * reach the top of the namespace, no further progress can be * made. Interrupt the DS chasing process, returning SERVFAIL. */ if (dns_name_equal(fctx->nsname, fetch->private->domain)) { result = DNS_R_SERVFAIL; goto cleanup; } /* Get nameservers from fetch before we destroy it. */ dns_rdataset_init(&nameservers); if (dns_rdataset_isassociated(&fetch->private->nameservers)) { dns_rdataset_clone(&fetch->private->nameservers, &nameservers); nsrdataset = &nameservers; /* Get domain from fetch before we destroy it. */ domain = dns_fixedname_initname(&fixed); dns_name_copy(fetch->private->domain, domain); } n = dns_name_countlabels(fctx->nsname); dns_name_getlabelsequence(fctx->nsname, 1, n - 1, fctx->nsname); FCTXTRACE("continuing to look for parent's NS records"); fetchctx_ref(fctx); result = dns_resolver_createfetch( res, fctx->nsname, dns_rdatatype_ns, domain, nsrdataset, NULL, NULL, 0, fctx->options, 0, fctx->qc, loop, resume_dslookup, fctx, &fctx->nsrrset, NULL, &fctx->nsfetch); if (result != ISC_R_SUCCESS) { fetchctx_unref(fctx); if (result == DNS_R_DUPLICATE) { result = DNS_R_SERVFAIL; } } if (dns_rdataset_isassociated(&nameservers)) { dns_rdataset_disassociate(&nameservers); } } cleanup: dns_resolver_destroyfetch(&fetch); if (result != ISC_R_SUCCESS) { /* An error occurred, tear down whole fctx */ fctx_done_unref(fctx, result); } fetchctx_detach(&fctx); } static void checknamessection(dns_message_t *message, dns_section_t section) { isc_result_t result; dns_name_t *name; dns_rdata_t rdata = DNS_RDATA_INIT; dns_rdataset_t *rdataset; for (result = dns_message_firstname(message, section); result == ISC_R_SUCCESS; result = dns_message_nextname(message, section)) { name = NULL; dns_message_currentname(message, section, &name); for (rdataset = ISC_LIST_HEAD(name->list); rdataset != NULL; rdataset = ISC_LIST_NEXT(rdataset, link)) { for (result = dns_rdataset_first(rdataset); result == ISC_R_SUCCESS; result = dns_rdataset_next(rdataset)) { dns_rdataset_current(rdataset, &rdata); if (!dns_rdata_checkowner(name, rdata.rdclass, rdata.type, false) || !dns_rdata_checknames(&rdata, name, NULL)) { rdataset->attributes |= DNS_RDATASETATTR_CHECKNAMES; } dns_rdata_reset(&rdata); } } } } static void checknames(dns_message_t *message) { checknamessection(message, DNS_SECTION_ANSWER); checknamessection(message, DNS_SECTION_AUTHORITY); checknamessection(message, DNS_SECTION_ADDITIONAL); } /* * Log server NSID at log level 'level' */ static void log_nsid(isc_buffer_t *opt, size_t nsid_len, resquery_t *query, int level, isc_mem_t *mctx) { static const char hex[17] = "0123456789abcdef"; char addrbuf[ISC_SOCKADDR_FORMATSIZE]; size_t buflen; unsigned char *p, *nsid; unsigned char *buf = NULL, *pbuf = NULL; REQUIRE(nsid_len <= UINT16_MAX); /* Allocate buffer for storing hex version of the NSID */ buflen = nsid_len * 2 + 1; buf = isc_mem_get(mctx, buflen); pbuf = isc_mem_get(mctx, nsid_len + 1); /* Convert to hex */ p = buf; nsid = isc_buffer_current(opt); for (size_t i = 0; i < nsid_len; i++) { *p++ = hex[(nsid[i] >> 4) & 0xf]; *p++ = hex[nsid[i] & 0xf]; } *p = '\0'; /* Make printable version */ p = pbuf; for (size_t i = 0; i < nsid_len; i++) { *p++ = isprint(nsid[i]) ? nsid[i] : '.'; } *p = '\0'; isc_sockaddr_format(&query->addrinfo->sockaddr, addrbuf, sizeof(addrbuf)); isc_log_write(dns_lctx, DNS_LOGCATEGORY_NSID, DNS_LOGMODULE_RESOLVER, level, "received NSID %s (\"%s\") from %s", buf, pbuf, addrbuf); isc_mem_put(mctx, pbuf, nsid_len + 1); isc_mem_put(mctx, buf, buflen); } static bool iscname(dns_message_t *message, dns_name_t *name) { isc_result_t result; result = dns_message_findname(message, DNS_SECTION_ANSWER, name, dns_rdatatype_cname, 0, NULL, NULL); return result == ISC_R_SUCCESS ? true : false; } static bool betterreferral(respctx_t *rctx) { isc_result_t result; dns_name_t *name; dns_rdataset_t *rdataset; for (result = dns_message_firstname(rctx->query->rmessage, DNS_SECTION_AUTHORITY); result == ISC_R_SUCCESS; result = dns_message_nextname(rctx->query->rmessage, DNS_SECTION_AUTHORITY)) { name = NULL; dns_message_currentname(rctx->query->rmessage, DNS_SECTION_AUTHORITY, &name); if (!isstrictsubdomain(name, rctx->fctx->domain)) { continue; } for (rdataset = ISC_LIST_HEAD(name->list); rdataset != NULL; rdataset = ISC_LIST_NEXT(rdataset, link)) { if (rdataset->type == dns_rdatatype_ns) { return true; } } } return false; } /* * Handles responses received in response to iterative queries sent by * resquery_send(). Sets up a response context (respctx_t). */ static void resquery_response(isc_result_t eresult, isc_region_t *region, void *arg) { isc_result_t result; resquery_t *query = (resquery_t *)arg; fetchctx_t *fctx = NULL; respctx_t *rctx = NULL; if (eresult == ISC_R_CANCELED) { return; } REQUIRE(VALID_QUERY(query)); fctx = query->fctx; REQUIRE(VALID_FCTX(fctx)); REQUIRE(fctx->tid == isc_tid()); QTRACE("response"); if (isc_sockaddr_pf(&query->addrinfo->sockaddr) == PF_INET) { inc_stats(fctx->res, dns_resstatscounter_responsev4); } else { inc_stats(fctx->res, dns_resstatscounter_responsev6); } rctx = isc_mem_get(fctx->mctx, sizeof(*rctx)); rctx_respinit(query, fctx, eresult, region, rctx); if (eresult == ISC_R_SHUTTINGDOWN || atomic_load_acquire(&fctx->res->exiting)) { result = ISC_R_SHUTTINGDOWN; FCTXTRACE("resolver shutting down"); rctx->finish = NULL; rctx_done(rctx, result); goto cleanup; } result = rctx_timedout(rctx); if (result == ISC_R_COMPLETE) { goto cleanup; } fctx->addrinfo = query->addrinfo; fctx->timeout = false; fctx->timeouts = 0; /* * Check whether the dispatcher has failed; if so we're done */ result = rctx_dispfail(rctx); if (result == ISC_R_COMPLETE) { goto cleanup; } if (query->tsig != NULL) { dns_message_setquerytsig(query->rmessage, query->tsig); } if (query->tsigkey != NULL) { result = dns_message_settsigkey(query->rmessage, query->tsigkey); if (result != ISC_R_SUCCESS) { FCTXTRACE3("unable to set tsig key", result); rctx_done(rctx, result); goto cleanup; } } dns_message_setclass(query->rmessage, fctx->res->rdclass); if ((rctx->retryopts & DNS_FETCHOPT_TCP) == 0) { if ((rctx->retryopts & DNS_FETCHOPT_NOEDNS0) == 0) { dns_adb_setudpsize( fctx->adb, query->addrinfo, isc_buffer_usedlength(&rctx->buffer)); } else { dns_adb_plainresponse(fctx->adb, query->addrinfo); } } /* * Parse response message. */ result = rctx_parse(rctx); if (result == ISC_R_COMPLETE) { goto cleanup; } /* * Log the incoming packet. */ rctx_logpacket(rctx); if (query->rmessage->rdclass != fctx->res->rdclass) { rctx->resend = true; FCTXTRACE("bad class"); rctx_done(rctx, result); goto cleanup; } /* * Process receive opt record. */ rctx->opt = dns_message_getopt(query->rmessage); if (rctx->opt != NULL) { rctx_opt(rctx); } if (query->rmessage->cc_bad && (rctx->retryopts & DNS_FETCHOPT_TCP) == 0) { /* * If the COOKIE is bad, assume it is an attack and * keep listening for a good answer. */ rctx->nextitem = true; if (isc_log_wouldlog(dns_lctx, ISC_LOG_INFO)) { char addrbuf[ISC_SOCKADDR_FORMATSIZE]; isc_sockaddr_format(&query->addrinfo->sockaddr, addrbuf, sizeof(addrbuf)); isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO, "bad cookie from %s", addrbuf); } rctx_done(rctx, result); goto cleanup; } /* * Is the question the same as the one we asked? * NOERROR/NXDOMAIN/YXDOMAIN/REFUSED/SERVFAIL/BADCOOKIE must * have the same question. FORMERR/NOTIMP if they have a * question section then it must match. */ switch (query->rmessage->rcode) { case dns_rcode_notimp: case dns_rcode_formerr: if (query->rmessage->counts[DNS_SECTION_QUESTION] == 0) { break; } FALLTHROUGH; case dns_rcode_nxrrset: /* Not expected. */ case dns_rcode_badcookie: case dns_rcode_noerror: case dns_rcode_nxdomain: case dns_rcode_yxdomain: case dns_rcode_refused: case dns_rcode_servfail: default: result = same_question(fctx, query->rmessage); if (result != ISC_R_SUCCESS) { FCTXTRACE3("question section invalid", result); rctx->nextitem = true; rctx_done(rctx, result); goto cleanup; } break; } if (query->rmessage->tsigkey == NULL && query->rmessage->tsig == NULL && query->rmessage->sig0 != NULL) { /* * If the message is not TSIG-signed (which has priorty) and is * SIG(0)-signed (which consumes more resources), then run an * asynchronous check. */ result = dns_message_checksig_async( query->rmessage, fctx->res->view, fctx->loop, resquery_response_continue, rctx); INSIST(result == DNS_R_WAIT); } else { /* * If the message is signed, check the signature. If not, this * returns success anyway. */ result = dns_message_checksig(query->rmessage, fctx->res->view); resquery_response_continue(rctx, result); } return; cleanup: isc_mem_putanddetach(&rctx->mctx, rctx, sizeof(*rctx)); } static void resquery_response_continue(void *arg, isc_result_t result) { respctx_t *rctx = arg; fetchctx_t *fctx = rctx->fctx; resquery_t *query = rctx->query; if (result != ISC_R_SUCCESS) { FCTXTRACE3("signature check failed", result); if (result == DNS_R_UNEXPECTEDTSIG || result == DNS_R_EXPECTEDTSIG) { rctx->nextitem = true; } rctx_done(rctx, result); goto cleanup; } /* * The dispatcher should ensure we only get responses with QR * set. */ INSIST((query->rmessage->flags & DNS_MESSAGEFLAG_QR) != 0); /* * If we have had a server cookie and don't get one retry over * TCP. This may be a misconfigured anycast server or an attempt * to send a spoofed response. Additionally retry over TCP if * require-cookie is true and we don't have a got client cookie. * Skip if we have a valid TSIG. */ if (dns_message_gettsig(query->rmessage, NULL) == NULL && !query->rmessage->cc_ok && !query->rmessage->cc_bad && (rctx->retryopts & DNS_FETCHOPT_TCP) == 0) { if (dns_adb_getcookie(query->addrinfo, NULL, 0) > CLIENT_COOKIE_SIZE) { if (isc_log_wouldlog(dns_lctx, ISC_LOG_INFO)) { char addrbuf[ISC_SOCKADDR_FORMATSIZE]; isc_sockaddr_format(&query->addrinfo->sockaddr, addrbuf, sizeof(addrbuf)); isc_log_write( dns_lctx, DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO, "missing expected cookie " "from %s", addrbuf); } rctx->retryopts |= DNS_FETCHOPT_TCP; rctx->resend = true; rctx_done(rctx, result); goto cleanup; } else if (fctx->res->view->peers != NULL) { dns_peer_t *peer = NULL; isc_netaddr_t netaddr; isc_netaddr_fromsockaddr(&netaddr, &query->addrinfo->sockaddr); result = dns_peerlist_peerbyaddr(fctx->res->view->peers, &netaddr, &peer); if (result == ISC_R_SUCCESS) { bool required = false; result = dns_peer_getrequirecookie(peer, &required); if (result == ISC_R_SUCCESS && required) { if (isc_log_wouldlog(dns_lctx, ISC_LOG_INFO)) { char addrbuf [ISC_SOCKADDR_FORMATSIZE]; isc_sockaddr_format( &query->addrinfo ->sockaddr, addrbuf, sizeof(addrbuf)); isc_log_write( dns_lctx, DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO, "missing required " "cookie " "from %s", addrbuf); } rctx->retryopts |= DNS_FETCHOPT_TCP; rctx->resend = true; rctx_done(rctx, result); goto cleanup; } } } } rctx_edns(rctx); /* * Deal with truncated responses by retrying using TCP. */ if ((query->rmessage->flags & DNS_MESSAGEFLAG_TC) != 0) { rctx->truncated = true; } if (rctx->truncated) { inc_stats(fctx->res, dns_resstatscounter_truncated); if ((rctx->retryopts & DNS_FETCHOPT_TCP) != 0) { rctx->broken_server = DNS_R_TRUNCATEDTCP; rctx->next_server = true; } else { rctx->retryopts |= DNS_FETCHOPT_TCP; rctx->resend = true; } FCTXTRACE3("message truncated", result); rctx_done(rctx, result); goto cleanup; } /* * Is it a query response? */ if (query->rmessage->opcode != dns_opcode_query) { rctx->broken_server = DNS_R_UNEXPECTEDOPCODE; rctx->next_server = true; FCTXTRACE("invalid message opcode"); rctx_done(rctx, result); goto cleanup; } /* * Update statistics about erroneous responses. */ switch (query->rmessage->rcode) { case dns_rcode_noerror: /* no error */ break; case dns_rcode_nxdomain: inc_stats(fctx->res, dns_resstatscounter_nxdomain); break; case dns_rcode_servfail: inc_stats(fctx->res, dns_resstatscounter_servfail); break; case dns_rcode_formerr: inc_stats(fctx->res, dns_resstatscounter_formerr); break; case dns_rcode_refused: inc_stats(fctx->res, dns_resstatscounter_refused); break; case dns_rcode_badvers: inc_stats(fctx->res, dns_resstatscounter_badvers); break; case dns_rcode_badcookie: inc_stats(fctx->res, dns_resstatscounter_badcookie); break; default: inc_stats(fctx->res, dns_resstatscounter_othererror); break; } /* * Bad server? */ result = rctx_badserver(rctx, result); if (result == ISC_R_COMPLETE) { goto cleanup; } /* * Lame server? */ result = rctx_lameserver(rctx); if (result == ISC_R_COMPLETE) { goto cleanup; } /* * Optionally call dns_rdata_checkowner() and * dns_rdata_checknames() to validate the names in the response * message. */ if ((fctx->res->options & DNS_RESOLVER_CHECKNAMES) != 0) { checknames(query->rmessage); } /* * Clear cache bits. */ FCTX_ATTR_CLR(fctx, (FCTX_ATTR_WANTNCACHE | FCTX_ATTR_WANTCACHE)); /* * Did we get any answers? */ if (query->rmessage->counts[DNS_SECTION_ANSWER] > 0 && (query->rmessage->rcode == dns_rcode_noerror || query->rmessage->rcode == dns_rcode_yxdomain || query->rmessage->rcode == dns_rcode_nxdomain)) { result = rctx_answer(rctx); if (result == ISC_R_COMPLETE) { goto cleanup; } } else if (query->rmessage->counts[DNS_SECTION_AUTHORITY] > 0 || query->rmessage->rcode == dns_rcode_noerror || query->rmessage->rcode == dns_rcode_nxdomain) { /* * This might be an NXDOMAIN, NXRRSET, or referral. * Call rctx_answer_none() to determine which it is. */ result = rctx_answer_none(rctx); switch (result) { case ISC_R_SUCCESS: case DNS_R_CHASEDSSERVERS: break; case DNS_R_DELEGATION: /* * With NOFOLLOW we want to pass return * DNS_R_DELEGATION to resume_qmin. */ if ((fctx->options & DNS_FETCHOPT_NOFOLLOW) == 0) { result = ISC_R_SUCCESS; } break; default: /* * Something has gone wrong. */ if (result == DNS_R_FORMERR) { rctx->next_server = true; } FCTXTRACE3("rctx_answer_none", result); rctx_done(rctx, result); goto cleanup; } } else { /* * The server is insane. */ /* XXXRTH Log */ rctx->broken_server = DNS_R_UNEXPECTEDRCODE; rctx->next_server = true; FCTXTRACE("broken server: unexpected rcode"); rctx_done(rctx, result); goto cleanup; } /* * Follow additional section data chains. */ rctx_additional(rctx); /* * Cache the cacheable parts of the message. This may also * cause work to be queued to the DNSSEC validator. */ if (WANTCACHE(fctx)) { isc_result_t tresult; tresult = cache_message(fctx, query->rmessage, query->addrinfo, rctx->now); if (tresult != ISC_R_SUCCESS) { FCTXTRACE3("cache_message complete", tresult); rctx_done(rctx, tresult); goto cleanup; } } /* * Negative caching */ rctx_ncache(rctx); FCTXTRACE("resquery_response done"); rctx_done(rctx, result); cleanup: isc_mem_putanddetach(&rctx->mctx, rctx, sizeof(*rctx)); } /* * rctx_respinit(): * Initialize the response context structure 'rctx' to all zeroes, then * set the loop, event, query and fctx information from * resquery_response(). */ static void rctx_respinit(resquery_t *query, fetchctx_t *fctx, isc_result_t result, isc_region_t *region, respctx_t *rctx) { *rctx = (respctx_t){ .result = result, .query = query, .fctx = fctx, .broken_type = badns_response, .retryopts = query->options }; if (result == ISC_R_SUCCESS) { REQUIRE(region != NULL); isc_buffer_init(&rctx->buffer, region->base, region->length); isc_buffer_add(&rctx->buffer, region->length); } else { isc_buffer_initnull(&rctx->buffer); } rctx->tnow = isc_time_now(); rctx->finish = &rctx->tnow; rctx->now = (isc_stdtime_t)isc_time_seconds(&rctx->tnow); isc_mem_attach(fctx->mctx, &rctx->mctx); } /* * rctx_answer_init(): * Clear and reinitialize those portions of 'rctx' that will be needed * when scanning the answer section of the response message. This can be * called more than once if scanning needs to be restarted (though * currently there are no cases in which this occurs). */ static void rctx_answer_init(respctx_t *rctx) { fetchctx_t *fctx = rctx->fctx; rctx->aa = ((rctx->query->rmessage->flags & DNS_MESSAGEFLAG_AA) != 0); if (rctx->aa) { rctx->trust = dns_trust_authanswer; } else { rctx->trust = dns_trust_answer; } /* * There can be multiple RRSIG and SIG records at a name so * we treat these types as a subset of ANY. */ rctx->type = fctx->type; if (rctx->type == dns_rdatatype_rrsig || rctx->type == dns_rdatatype_sig) { rctx->type = dns_rdatatype_any; } /* * Bigger than any valid DNAME label count. */ rctx->dname_labels = dns_name_countlabels(fctx->name); rctx->domain_labels = dns_name_countlabels(fctx->domain); rctx->found_type = dns_rdatatype_none; rctx->aname = NULL; rctx->ardataset = NULL; rctx->cname = NULL; rctx->crdataset = NULL; rctx->dname = NULL; rctx->drdataset = NULL; rctx->ns_name = NULL; rctx->ns_rdataset = NULL; rctx->soa_name = NULL; rctx->ds_name = NULL; rctx->found_name = NULL; } /* * rctx_dispfail(): * Handle the case where the dispatcher failed */ static isc_result_t rctx_dispfail(respctx_t *rctx) { fetchctx_t *fctx = rctx->fctx; if (rctx->result == ISC_R_SUCCESS) { return ISC_R_SUCCESS; } /* * There's no hope for this response. */ rctx->next_server = true; /* * If this is a network failure, the operation is cancelled, * or the network manager is being shut down, we mark the server * as bad so that we won't try it for this fetch again. Also * adjust finish and no_response so that we penalize this * address in SRTT adjustments later. */ switch (rctx->result) { case ISC_R_EOF: case ISC_R_HOSTDOWN: case ISC_R_HOSTUNREACH: case ISC_R_NETDOWN: case ISC_R_NETUNREACH: case ISC_R_CONNREFUSED: case ISC_R_CONNECTIONRESET: case ISC_R_INVALIDPROTO: case ISC_R_CANCELED: case ISC_R_SHUTTINGDOWN: rctx->broken_server = rctx->result; rctx->broken_type = badns_unreachable; rctx->finish = NULL; rctx->no_response = true; break; default: break; } FCTXTRACE3("dispatcher failure", rctx->result); rctx_done(rctx, ISC_R_SUCCESS); return ISC_R_COMPLETE; } /* * rctx_timedout(): * Handle the case where a dispatch read timed out. */ static isc_result_t rctx_timedout(respctx_t *rctx) { fetchctx_t *fctx = rctx->fctx; if (rctx->result == ISC_R_TIMEDOUT) { isc_time_t now; inc_stats(fctx->res, dns_resstatscounter_querytimeout); FCTX_ATTR_CLR(fctx, FCTX_ATTR_ADDRWAIT); fctx->timeout = true; fctx->timeouts++; now = isc_time_now(); /* netmgr timeouts are accurate to the millisecond */ if (isc_time_microdiff(&fctx->expires, &now) < US_PER_MS) { FCTXTRACE("query timed out; stopped trying to make " "fetch happen"); } else { FCTXTRACE("query timed out; trying next server"); /* try next server */ rctx->no_response = true; rctx->finish = NULL; rctx->next_server = true; } rctx_done(rctx, rctx->result); return ISC_R_COMPLETE; } return ISC_R_SUCCESS; } /* * rctx_parse(): * Parse the response message. */ static isc_result_t rctx_parse(respctx_t *rctx) { isc_result_t result; fetchctx_t *fctx = rctx->fctx; resquery_t *query = rctx->query; result = dns_message_parse(query->rmessage, &rctx->buffer, 0); if (result == ISC_R_SUCCESS) { return ISC_R_SUCCESS; } FCTXTRACE3("message failed to parse", result); switch (result) { case ISC_R_UNEXPECTEDEND: if (query->rmessage->question_ok && (query->rmessage->flags & DNS_MESSAGEFLAG_TC) != 0 && (rctx->retryopts & DNS_FETCHOPT_TCP) == 0) { /* * We defer retrying via TCP for a bit so we can * check out this message further. */ rctx->truncated = true; return ISC_R_SUCCESS; } /* * Either the message ended prematurely, * and/or wasn't marked as being truncated, * and/or this is a response to a query we * sent over TCP. In all of these cases, * something is wrong with the remote * server and we don't want to retry using * TCP. */ if ((rctx->retryopts & DNS_FETCHOPT_NOEDNS0) == 0) { /* * The problem might be that they * don't understand EDNS0. Turn it * off and try again. */ rctx->retryopts |= DNS_FETCHOPT_NOEDNS0; rctx->resend = true; add_bad_edns(fctx, &query->addrinfo->sockaddr); inc_stats(fctx->res, dns_resstatscounter_edns0fail); } else { rctx->broken_server = result; rctx->next_server = true; } rctx_done(rctx, result); break; case DNS_R_FORMERR: if ((rctx->retryopts & DNS_FETCHOPT_NOEDNS0) == 0) { /* * The problem might be that they * don't understand EDNS0. Turn it * off and try again. */ rctx->retryopts |= DNS_FETCHOPT_NOEDNS0; rctx->resend = true; add_bad_edns(fctx, &query->addrinfo->sockaddr); inc_stats(fctx->res, dns_resstatscounter_edns0fail); } else { rctx->broken_server = DNS_R_UNEXPECTEDRCODE; rctx->next_server = true; } rctx_done(rctx, result); break; default: /* * Something bad has happened. */ rctx_done(rctx, result); break; } return ISC_R_COMPLETE; } /* * rctx_opt(): * Process the OPT record in the response. */ static void rctx_opt(respctx_t *rctx) { resquery_t *query = rctx->query; fetchctx_t *fctx = rctx->fctx; dns_rdata_t rdata; isc_buffer_t optbuf; isc_result_t result; bool seen_cookie = false; bool seen_nsid = false; result = dns_rdataset_first(rctx->opt); if (result != ISC_R_SUCCESS) { return; } dns_rdata_init(&rdata); dns_rdataset_current(rctx->opt, &rdata); isc_buffer_init(&optbuf, rdata.data, rdata.length); isc_buffer_add(&optbuf, rdata.length); while (isc_buffer_remaininglength(&optbuf) >= 4) { uint16_t optcode; uint16_t optlen; unsigned char *optvalue; unsigned char cookie[CLIENT_COOKIE_SIZE]; optcode = isc_buffer_getuint16(&optbuf); optlen = isc_buffer_getuint16(&optbuf); INSIST(optlen <= isc_buffer_remaininglength(&optbuf)); switch (optcode) { case DNS_OPT_NSID: if (seen_nsid) { break; } seen_nsid = true; if ((query->options & DNS_FETCHOPT_WANTNSID) != 0) { log_nsid(&optbuf, optlen, query, ISC_LOG_INFO, fctx->mctx); } break; case DNS_OPT_COOKIE: /* Only process the first cookie option. */ if (seen_cookie) { break; } seen_cookie = true; optvalue = isc_buffer_current(&optbuf); compute_cc(query, cookie, sizeof(cookie)); INSIST(query->rmessage->cc_bad == 0 && query->rmessage->cc_ok == 0); inc_stats(fctx->res, dns_resstatscounter_cookiein); if (optlen < CLIENT_COOKIE_SIZE || memcmp(cookie, optvalue, CLIENT_COOKIE_SIZE) != 0) { query->rmessage->cc_bad = 1; break; } /* Cookie OK */ if (optlen == CLIENT_COOKIE_SIZE) { query->rmessage->cc_echoed = 1; } else { query->rmessage->cc_ok = 1; inc_stats(fctx->res, dns_resstatscounter_cookieok); dns_adb_setcookie(fctx->adb, query->addrinfo, optvalue, optlen); } break; default: break; } isc_buffer_forward(&optbuf, optlen); } INSIST(isc_buffer_remaininglength(&optbuf) == 0U); } /* * rctx_edns(): * Determine whether the remote server is using EDNS correctly or * incorrectly and record that information if needed. */ static void rctx_edns(respctx_t *rctx) { resquery_t *query = rctx->query; fetchctx_t *fctx = rctx->fctx; /* * We have an affirmative response to the query and we have * previously got a response from this server which indicated * EDNS may not be supported so we can now cache the lack of * EDNS support. */ if (rctx->opt == NULL && !EDNSOK(query->addrinfo) && (query->rmessage->rcode == dns_rcode_noerror || query->rmessage->rcode == dns_rcode_nxdomain || query->rmessage->rcode == dns_rcode_refused || query->rmessage->rcode == dns_rcode_yxdomain) && bad_edns(fctx, &query->addrinfo->sockaddr)) { dns_message_logpacket( query->rmessage, "received packet (bad edns) from", &query->addrinfo->sockaddr, DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER, ISC_LOG_DEBUG(3), fctx->mctx); dns_adb_changeflags(fctx->adb, query->addrinfo, FCTX_ADDRINFO_NOEDNS0, FCTX_ADDRINFO_NOEDNS0); } else if (rctx->opt == NULL && (query->rmessage->flags & DNS_MESSAGEFLAG_TC) == 0 && !EDNSOK(query->addrinfo) && (query->rmessage->rcode == dns_rcode_noerror || query->rmessage->rcode == dns_rcode_nxdomain) && (rctx->retryopts & DNS_FETCHOPT_NOEDNS0) == 0) { /* * We didn't get a OPT record in response to a EDNS * query. * * Old versions of named incorrectly drop the OPT record * when there is a signed, truncated response so we * check that TC is not set. * * Record that the server is not talking EDNS. While * this should be safe to do for any rcode we limit it * to NOERROR and NXDOMAIN. */ dns_message_logpacket( query->rmessage, "received packet (no opt) from", &query->addrinfo->sockaddr, DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER, ISC_LOG_DEBUG(3), fctx->mctx); dns_adb_changeflags(fctx->adb, query->addrinfo, FCTX_ADDRINFO_NOEDNS0, FCTX_ADDRINFO_NOEDNS0); } /* * If we get a non error EDNS response record the fact so we * won't fallback to plain DNS in the future for this server. */ if (rctx->opt != NULL && !EDNSOK(query->addrinfo) && (rctx->retryopts & DNS_FETCHOPT_NOEDNS0) == 0 && (query->rmessage->rcode == dns_rcode_noerror || query->rmessage->rcode == dns_rcode_nxdomain || query->rmessage->rcode == dns_rcode_refused || query->rmessage->rcode == dns_rcode_yxdomain)) { dns_adb_changeflags(fctx->adb, query->addrinfo, FCTX_ADDRINFO_EDNSOK, FCTX_ADDRINFO_EDNSOK); } } /* * rctx_answer(): * We might have answers, or we might have a malformed delegation with * records in the answer section. Call rctx_answer_positive() or * rctx_answer_none() as appropriate. */ static isc_result_t rctx_answer(respctx_t *rctx) { isc_result_t result; fetchctx_t *fctx = rctx->fctx; resquery_t *query = rctx->query; if ((query->rmessage->flags & DNS_MESSAGEFLAG_AA) != 0 || ISFORWARDER(query->addrinfo)) { result = rctx_answer_positive(rctx); if (result != ISC_R_SUCCESS) { FCTXTRACE3("rctx_answer_positive (AA/fwd)", result); } } else if (iscname(query->rmessage, fctx->name) && fctx->type != dns_rdatatype_any && fctx->type != dns_rdatatype_cname) { /* * A BIND8 server could return a non-authoritative * answer when a CNAME is followed. We should treat * it as a valid answer. */ result = rctx_answer_positive(rctx); if (result != ISC_R_SUCCESS) { FCTXTRACE3("rctx_answer_positive (!ANY/!CNAME)", result); } } else if (fctx->type != dns_rdatatype_ns && !betterreferral(rctx)) { result = rctx_answer_positive(rctx); if (result != ISC_R_SUCCESS) { FCTXTRACE3("rctx_answer_positive (!NS)", result); } } else { /* * This may be a delegation. First let's check for */ if (fctx->type == dns_rdatatype_ns) { /* * A BIND 8 server could incorrectly return a * non-authoritative answer to an NS query * instead of a referral. Since this answer * lacks the SIGs necessary to do DNSSEC * validation, we must invoke the following * special kludge to treat it as a referral. */ rctx->ns_in_answer = true; result = rctx_answer_none(rctx); if (result != ISC_R_SUCCESS) { FCTXTRACE3("rctx_answer_none (NS)", result); } } else { /* * Some other servers may still somehow include * an answer when it should return a referral * with an empty answer. Check to see if we can * treat this as a referral by ignoring the * answer. Further more, there may be an * implementation that moves A/AAAA glue records * to the answer section for that type of * delegation when the query is for that glue * record. glue_in_answer will handle * such a corner case. */ rctx->glue_in_answer = true; result = rctx_answer_none(rctx); if (result != ISC_R_SUCCESS) { FCTXTRACE3("rctx_answer_none", result); } } if (result == DNS_R_DELEGATION) { /* * With NOFOLLOW we want to return DNS_R_DELEGATION to * resume_qmin. */ if ((rctx->fctx->options & DNS_FETCHOPT_NOFOLLOW) != 0) { return result; } result = ISC_R_SUCCESS; } else { /* * At this point, AA is not set, the response * is not a referral, and the server is not a * forwarder. It is technically lame and it's * easier to treat it as such than to figure out * some more elaborate course of action. */ rctx->broken_server = DNS_R_LAME; rctx->next_server = true; FCTXTRACE3("rctx_answer lame", result); rctx_done(rctx, result); return ISC_R_COMPLETE; } } if (result != ISC_R_SUCCESS) { if (result == DNS_R_FORMERR) { rctx->next_server = true; } FCTXTRACE3("rctx_answer failed", result); rctx_done(rctx, result); return ISC_R_COMPLETE; } return ISC_R_SUCCESS; } /* * rctx_answer_positive(): * Handles positive responses. Depending which type of answer this is * (matching QNAME/QTYPE, CNAME, DNAME, ANY) calls the proper routine * to handle it (rctx_answer_match(), rctx_answer_cname(), * rctx_answer_dname(), rctx_answer_any()). */ static isc_result_t rctx_answer_positive(respctx_t *rctx) { isc_result_t result; fetchctx_t *fctx = rctx->fctx; FCTXTRACE("rctx_answer_positive"); rctx_answer_init(rctx); rctx_answer_scan(rctx); /* * Determine which type of positive answer this is: * type ANY, CNAME, DNAME, or an answer matching QNAME/QTYPE. * Call the appropriate routine to handle the answer type. */ if (rctx->aname != NULL && rctx->type == dns_rdatatype_any) { result = rctx_answer_any(rctx); if (result == ISC_R_COMPLETE) { return rctx->result; } } else if (rctx->aname != NULL) { result = rctx_answer_match(rctx); if (result == ISC_R_COMPLETE) { return rctx->result; } } else if (rctx->cname != NULL) { result = rctx_answer_cname(rctx); if (result == ISC_R_COMPLETE) { return rctx->result; } } else if (rctx->dname != NULL) { result = rctx_answer_dname(rctx); if (result == ISC_R_COMPLETE) { return rctx->result; } } else { log_formerr(fctx, "reply has no answer"); return DNS_R_FORMERR; } /* * This response is now potentially cacheable. */ FCTX_ATTR_SET(fctx, FCTX_ATTR_WANTCACHE); /* * Did chaining end before we got the final answer? */ if (rctx->chaining) { return ISC_R_SUCCESS; } /* * We didn't end with an incomplete chain, so the rcode should * be "no error". */ if (rctx->query->rmessage->rcode != dns_rcode_noerror) { log_formerr(fctx, "CNAME/DNAME chain complete, but RCODE " "indicates error"); return DNS_R_FORMERR; } /* * Cache records in the authority section, if * there are any suitable for caching. */ rctx_authority_positive(rctx); log_ns_ttl(fctx, "rctx_answer"); if (rctx->ns_rdataset != NULL && dns_name_equal(fctx->domain, rctx->ns_name) && !dns_name_equal(rctx->ns_name, dns_rootname)) { trim_ns_ttl(fctx, rctx->ns_name, rctx->ns_rdataset); } return ISC_R_SUCCESS; } /* * rctx_answer_scan(): * Perform a single pass over the answer section of a response, looking * for an answer that matches QNAME/QTYPE, or a CNAME matching QNAME, or * a covering DNAME. If more than one rdataset is found matching these * criteria, then only one is kept. Order of preference is 1) the * shortest DNAME, 2) the first matching answer, or 3) the first CNAME. */ static void rctx_answer_scan(respctx_t *rctx) { isc_result_t result; fetchctx_t *fctx = rctx->fctx; dns_rdataset_t *rdataset = NULL; for (result = dns_message_firstname(rctx->query->rmessage, DNS_SECTION_ANSWER); result == ISC_R_SUCCESS; result = dns_message_nextname(rctx->query->rmessage, DNS_SECTION_ANSWER)) { int order; unsigned int nlabels; dns_namereln_t namereln; dns_name_t *name = NULL; dns_message_currentname(rctx->query->rmessage, DNS_SECTION_ANSWER, &name); namereln = dns_name_fullcompare(fctx->name, name, &order, &nlabels); switch (namereln) { case dns_namereln_equal: for (rdataset = ISC_LIST_HEAD(name->list); rdataset != NULL; rdataset = ISC_LIST_NEXT(rdataset, link)) { if (rdataset->type == rctx->type || rctx->type == dns_rdatatype_any) { rctx->aname = name; if (rctx->type != dns_rdatatype_any) { rctx->ardataset = rdataset; } break; } if (rdataset->type == dns_rdatatype_cname) { rctx->cname = name; rctx->crdataset = rdataset; break; } } break; case dns_namereln_subdomain: /* * Don't accept DNAME from parent namespace. */ if (name_external(name, dns_rdatatype_dname, fctx)) { continue; } /* * In-scope DNAME records must have at least * as many labels as the domain being queried. * They also must be less that qname's labels * and any previously found dname. */ if (nlabels >= rctx->dname_labels || nlabels < rctx->domain_labels) { continue; } /* * We are looking for the shortest DNAME if * there are multiple ones (which there * shouldn't be). */ for (rdataset = ISC_LIST_HEAD(name->list); rdataset != NULL; rdataset = ISC_LIST_NEXT(rdataset, link)) { if (rdataset->type != dns_rdatatype_dname) { continue; } rctx->dname = name; rctx->drdataset = rdataset; rctx->dname_labels = nlabels; break; } break; default: break; } } /* * If a DNAME was found, then any CNAME or other answer matching * QNAME that may also have been found must be ignored. * Similarly, if a matching answer was found along with a CNAME, * the CNAME must be ignored. */ if (rctx->dname != NULL) { rctx->aname = NULL; rctx->ardataset = NULL; rctx->cname = NULL; rctx->crdataset = NULL; } else if (rctx->aname != NULL) { rctx->cname = NULL; rctx->crdataset = NULL; } } /* * rctx_answer_any(): * Handle responses to queries of type ANY. Scan the answer section, * and as long as each RRset is of a type that is valid in the answer * section, and the rdata isn't filtered, cache it. */ static isc_result_t rctx_answer_any(respctx_t *rctx) { dns_rdataset_t *rdataset = NULL; fetchctx_t *fctx = rctx->fctx; for (rdataset = ISC_LIST_HEAD(rctx->aname->list); rdataset != NULL; rdataset = ISC_LIST_NEXT(rdataset, link)) { if (!validinanswer(rdataset, fctx)) { rctx->result = DNS_R_FORMERR; return ISC_R_COMPLETE; } if ((fctx->type == dns_rdatatype_sig || fctx->type == dns_rdatatype_rrsig) && rdataset->type != fctx->type) { continue; } if ((rdataset->type == dns_rdatatype_a || rdataset->type == dns_rdatatype_aaaa) && !is_answeraddress_allowed(fctx->res->view, rctx->aname, rdataset)) { rctx->result = DNS_R_SERVFAIL; return ISC_R_COMPLETE; } if ((rdataset->type == dns_rdatatype_cname || rdataset->type == dns_rdatatype_dname) && !is_answertarget_allowed(fctx, fctx->name, rctx->aname, rdataset, NULL)) { rctx->result = DNS_R_SERVFAIL; return ISC_R_COMPLETE; } rctx->aname->attributes.cache = true; rctx->aname->attributes.answer = true; rdataset->attributes |= DNS_RDATASETATTR_ANSWER; rdataset->attributes |= DNS_RDATASETATTR_CACHE; rdataset->trust = rctx->trust; (void)dns_rdataset_additionaldata(rdataset, rctx->aname, check_related, rctx); } return ISC_R_SUCCESS; } /* * rctx_answer_match(): * Handle responses that match the QNAME/QTYPE of the resolver query. * If QTYPE is valid in the answer section and the rdata isn't filtered, * the answer can be cached. If there is additional section data related * to the answer, it can be cached as well. */ static isc_result_t rctx_answer_match(respctx_t *rctx) { dns_rdataset_t *sigrdataset = NULL; fetchctx_t *fctx = rctx->fctx; if (!validinanswer(rctx->ardataset, fctx)) { rctx->result = DNS_R_FORMERR; return ISC_R_COMPLETE; } if ((rctx->ardataset->type == dns_rdatatype_a || rctx->ardataset->type == dns_rdatatype_aaaa) && !is_answeraddress_allowed(fctx->res->view, rctx->aname, rctx->ardataset)) { rctx->result = DNS_R_SERVFAIL; return ISC_R_COMPLETE; } if ((rctx->ardataset->type == dns_rdatatype_cname || rctx->ardataset->type == dns_rdatatype_dname) && rctx->type != rctx->ardataset->type && rctx->type != dns_rdatatype_any && !is_answertarget_allowed(fctx, fctx->name, rctx->aname, rctx->ardataset, NULL)) { rctx->result = DNS_R_SERVFAIL; return ISC_R_COMPLETE; } rctx->aname->attributes.cache = true; rctx->aname->attributes.answer = true; rctx->ardataset->attributes |= DNS_RDATASETATTR_ANSWER; rctx->ardataset->attributes |= DNS_RDATASETATTR_CACHE; rctx->ardataset->trust = rctx->trust; (void)dns_rdataset_additionaldata(rctx->ardataset, rctx->aname, check_related, rctx); for (sigrdataset = ISC_LIST_HEAD(rctx->aname->list); sigrdataset != NULL; sigrdataset = ISC_LIST_NEXT(sigrdataset, link)) { if (!validinanswer(sigrdataset, fctx)) { rctx->result = DNS_R_FORMERR; return ISC_R_COMPLETE; } if (sigrdataset->type != dns_rdatatype_rrsig || sigrdataset->covers != rctx->type) { continue; } sigrdataset->attributes |= DNS_RDATASETATTR_ANSWERSIG; sigrdataset->attributes |= DNS_RDATASETATTR_CACHE; sigrdataset->trust = rctx->trust; break; } return ISC_R_SUCCESS; } /* * rctx_answer_cname(): * Handle answers containing a CNAME. Cache the CNAME, and flag that * there may be additional chain answers to find. */ static isc_result_t rctx_answer_cname(respctx_t *rctx) { dns_rdataset_t *sigrdataset = NULL; fetchctx_t *fctx = rctx->fctx; if (!validinanswer(rctx->crdataset, fctx)) { rctx->result = DNS_R_FORMERR; return ISC_R_COMPLETE; } if (rctx->type == dns_rdatatype_rrsig || rctx->type == dns_rdatatype_key || rctx->type == dns_rdatatype_nsec) { char buf[DNS_RDATATYPE_FORMATSIZE]; dns_rdatatype_format(rctx->type, buf, sizeof(buf)); log_formerr(fctx, "CNAME response for %s RR", buf); rctx->result = DNS_R_FORMERR; return ISC_R_COMPLETE; } if (!is_answertarget_allowed(fctx, fctx->name, rctx->cname, rctx->crdataset, NULL)) { rctx->result = DNS_R_SERVFAIL; return ISC_R_COMPLETE; } rctx->cname->attributes.cache = true; rctx->cname->attributes.answer = true; rctx->cname->attributes.chaining = true; rctx->crdataset->attributes |= DNS_RDATASETATTR_ANSWER; rctx->crdataset->attributes |= DNS_RDATASETATTR_CACHE; rctx->crdataset->attributes |= DNS_RDATASETATTR_CHAINING; rctx->crdataset->trust = rctx->trust; for (sigrdataset = ISC_LIST_HEAD(rctx->cname->list); sigrdataset != NULL; sigrdataset = ISC_LIST_NEXT(sigrdataset, link)) { if (!validinanswer(sigrdataset, fctx)) { rctx->result = DNS_R_FORMERR; return ISC_R_COMPLETE; } if (sigrdataset->type != dns_rdatatype_rrsig || sigrdataset->covers != dns_rdatatype_cname) { continue; } sigrdataset->attributes |= DNS_RDATASETATTR_ANSWERSIG; sigrdataset->attributes |= DNS_RDATASETATTR_CACHE; sigrdataset->trust = rctx->trust; break; } rctx->chaining = true; return ISC_R_SUCCESS; } /* * rctx_answer_dname(): * Handle responses with covering DNAME records. */ static isc_result_t rctx_answer_dname(respctx_t *rctx) { dns_rdataset_t *sigrdataset = NULL; fetchctx_t *fctx = rctx->fctx; if (!validinanswer(rctx->drdataset, fctx)) { rctx->result = DNS_R_FORMERR; return ISC_R_COMPLETE; } if (!is_answertarget_allowed(fctx, fctx->name, rctx->dname, rctx->drdataset, &rctx->chaining)) { rctx->result = DNS_R_SERVFAIL; return ISC_R_COMPLETE; } rctx->dname->attributes.cache = true; rctx->dname->attributes.answer = true; rctx->dname->attributes.chaining = true; rctx->drdataset->attributes |= DNS_RDATASETATTR_ANSWER; rctx->drdataset->attributes |= DNS_RDATASETATTR_CACHE; rctx->drdataset->attributes |= DNS_RDATASETATTR_CHAINING; rctx->drdataset->trust = rctx->trust; for (sigrdataset = ISC_LIST_HEAD(rctx->dname->list); sigrdataset != NULL; sigrdataset = ISC_LIST_NEXT(sigrdataset, link)) { if (!validinanswer(sigrdataset, fctx)) { rctx->result = DNS_R_FORMERR; return ISC_R_COMPLETE; } if (sigrdataset->type != dns_rdatatype_rrsig || sigrdataset->covers != dns_rdatatype_dname) { continue; } sigrdataset->attributes |= DNS_RDATASETATTR_ANSWERSIG; sigrdataset->attributes |= DNS_RDATASETATTR_CACHE; sigrdataset->trust = rctx->trust; break; } return ISC_R_SUCCESS; } /* * rctx_authority_positive(): * Examine the records in the authority section (if there are any) for a * positive answer. We expect the names for all rdatasets in this * section to be subdomains of the domain being queried; any that are * not are skipped. We expect to find only *one* owner name; any names * after the first one processed are ignored. We expect to find only * rdatasets of type NS, RRSIG, or SIG; all others are ignored. Whatever * remains can be cached at trust level authauthority or additional * (depending on whether the AA bit was set on the answer). */ static void rctx_authority_positive(respctx_t *rctx) { fetchctx_t *fctx = rctx->fctx; bool done = false; isc_result_t result; result = dns_message_firstname(rctx->query->rmessage, DNS_SECTION_AUTHORITY); while (!done && result == ISC_R_SUCCESS) { dns_name_t *name = NULL; dns_message_currentname(rctx->query->rmessage, DNS_SECTION_AUTHORITY, &name); if (!name_external(name, dns_rdatatype_ns, fctx)) { dns_rdataset_t *rdataset = NULL; /* * We expect to find NS or SIG NS rdatasets, and * nothing else. */ for (rdataset = ISC_LIST_HEAD(name->list); rdataset != NULL; rdataset = ISC_LIST_NEXT(rdataset, link)) { if (rdataset->type == dns_rdatatype_ns || (rdataset->type == dns_rdatatype_rrsig && rdataset->covers == dns_rdatatype_ns)) { name->attributes.cache = true; rdataset->attributes |= DNS_RDATASETATTR_CACHE; if (rctx->aa) { rdataset->trust = dns_trust_authauthority; } else { rdataset->trust = dns_trust_additional; } if (rdataset->type == dns_rdatatype_ns) { rctx->ns_name = name; rctx->ns_rdataset = rdataset; } /* * Mark any additional data * related to this rdataset. */ (void)dns_rdataset_additionaldata( rdataset, name, check_related, rctx); done = true; } } } result = dns_message_nextname(rctx->query->rmessage, DNS_SECTION_AUTHORITY); } } /* * rctx_answer_none(): * Handles a response without an answer: this is either a negative * response (NXDOMAIN or NXRRSET) or a referral. Determine which it is, * then either scan the authority section for negative caching and * DNSSEC proof of nonexistence, or else call rctx_referral(). */ static isc_result_t rctx_answer_none(respctx_t *rctx) { isc_result_t result; fetchctx_t *fctx = rctx->fctx; FCTXTRACE("rctx_answer_none"); rctx_answer_init(rctx); /* * Sometimes we can tell if its a negative response by looking * at the message header. */ if (rctx->query->rmessage->rcode == dns_rcode_nxdomain || (rctx->query->rmessage->counts[DNS_SECTION_ANSWER] == 0 && rctx->query->rmessage->counts[DNS_SECTION_AUTHORITY] == 0)) { rctx->negative = true; } /* * Process the authority section */ result = rctx_authority_negative(rctx); if (result == ISC_R_COMPLETE) { return rctx->result; } log_ns_ttl(fctx, "rctx_answer_none"); if (rctx->ns_rdataset != NULL && dns_name_equal(fctx->domain, rctx->ns_name) && !dns_name_equal(rctx->ns_name, dns_rootname)) { trim_ns_ttl(fctx, rctx->ns_name, rctx->ns_rdataset); } /* * A negative response has a SOA record (Type 2) * and a optional NS RRset (Type 1) or it has neither * a SOA or a NS RRset (Type 3, handled above) or * rcode is NXDOMAIN (handled above) in which case * the NS RRset is allowed (Type 4). */ if (rctx->soa_name != NULL) { rctx->negative = true; } if (!rctx->ns_in_answer && !rctx->glue_in_answer) { /* * Process DNSSEC records in the authority section. */ result = rctx_authority_dnssec(rctx); if (result == ISC_R_COMPLETE) { return rctx->result; } } /* * Trigger lookups for DNS nameservers. */ if (rctx->negative && rctx->query->rmessage->rcode == dns_rcode_noerror && fctx->type == dns_rdatatype_ds && rctx->soa_name != NULL && dns_name_equal(rctx->soa_name, fctx->name) && !dns_name_equal(fctx->name, dns_rootname)) { return DNS_R_CHASEDSSERVERS; } /* * Did we find anything? */ if (!rctx->negative && rctx->ns_name == NULL) { /* * The responder is insane. */ if (rctx->found_name == NULL) { log_formerr(fctx, "invalid response"); return DNS_R_FORMERR; } if (!dns_name_issubdomain(rctx->found_name, fctx->domain)) { char nbuf[DNS_NAME_FORMATSIZE]; char dbuf[DNS_NAME_FORMATSIZE]; char tbuf[DNS_RDATATYPE_FORMATSIZE]; dns_rdatatype_format(rctx->found_type, tbuf, sizeof(tbuf)); dns_name_format(rctx->found_name, nbuf, sizeof(nbuf)); dns_name_format(fctx->domain, dbuf, sizeof(dbuf)); log_formerr(fctx, "Name %s (%s) not subdomain" " of zone %s -- invalid response", nbuf, tbuf, dbuf); } else { log_formerr(fctx, "invalid response"); } return DNS_R_FORMERR; } /* * If we found both NS and SOA, they should be the same name. */ if (rctx->ns_name != NULL && rctx->soa_name != NULL && rctx->ns_name != rctx->soa_name) { log_formerr(fctx, "NS/SOA mismatch"); return DNS_R_FORMERR; } /* * Handle a referral. */ result = rctx_referral(rctx); if (result == ISC_R_COMPLETE) { return rctx->result; } /* * Since we're not doing a referral, we don't want to cache any * NS RRs we may have found. */ if (rctx->ns_name != NULL) { rctx->ns_name->attributes.cache = false; } if (rctx->negative) { FCTX_ATTR_SET(fctx, FCTX_ATTR_WANTNCACHE); } return ISC_R_SUCCESS; } /* * rctx_authority_negative(): * Scan the authority section of a negative answer, handling * NS and SOA records. (Note that this function does *not* handle * DNSSEC records; those are addressed separately in * rctx_authority_dnssec() below.) */ static isc_result_t rctx_authority_negative(respctx_t *rctx) { isc_result_t result; fetchctx_t *fctx = rctx->fctx; dns_section_t section; dns_rdataset_t *rdataset = NULL; bool finished = false; if (rctx->ns_in_answer) { INSIST(fctx->type == dns_rdatatype_ns); section = DNS_SECTION_ANSWER; } else { section = DNS_SECTION_AUTHORITY; } result = dns_message_firstname(rctx->query->rmessage, section); if (result != ISC_R_SUCCESS) { return ISC_R_SUCCESS; } while (!finished) { dns_name_t *name = NULL; dns_message_currentname(rctx->query->rmessage, section, &name); result = dns_message_nextname(rctx->query->rmessage, section); if (result != ISC_R_SUCCESS) { finished = true; } if (!dns_name_issubdomain(name, fctx->domain)) { continue; } for (rdataset = ISC_LIST_HEAD(name->list); rdataset != NULL; rdataset = ISC_LIST_NEXT(rdataset, link)) { dns_rdatatype_t type = rdataset->type; if (type == dns_rdatatype_rrsig) { type = rdataset->covers; } if ((type == dns_rdatatype_ns || type == dns_rdatatype_soa) && !dns_name_issubdomain(fctx->name, name)) { char qbuf[DNS_NAME_FORMATSIZE]; char nbuf[DNS_NAME_FORMATSIZE]; char tbuf[DNS_RDATATYPE_FORMATSIZE]; dns_rdatatype_format(type, tbuf, sizeof(tbuf)); dns_name_format(name, nbuf, sizeof(nbuf)); dns_name_format(fctx->name, qbuf, sizeof(qbuf)); log_formerr(fctx, "unrelated %s %s in " "%s authority section", tbuf, nbuf, qbuf); break; } switch (type) { case dns_rdatatype_ns: /* * NS or RRSIG NS. * * Only one set of NS RRs is allowed. */ if (rdataset->type == dns_rdatatype_ns) { if (rctx->ns_name != NULL && name != rctx->ns_name) { log_formerr(fctx, "multiple NS " "RRsets " "in " "authority " "section"); rctx->result = DNS_R_FORMERR; return ISC_R_COMPLETE; } rctx->ns_name = name; rctx->ns_rdataset = rdataset; } name->attributes.cache = true; rdataset->attributes |= DNS_RDATASETATTR_CACHE; rdataset->trust = dns_trust_glue; break; case dns_rdatatype_soa: /* * SOA, or RRSIG SOA. * * Only one SOA is allowed. */ if (rdataset->type == dns_rdatatype_soa) { if (rctx->soa_name != NULL && name != rctx->soa_name) { log_formerr(fctx, "multiple " "SOA RRs " "in " "authority " "section"); rctx->result = DNS_R_FORMERR; return ISC_R_COMPLETE; } rctx->soa_name = name; } name->attributes.ncache = true; rdataset->attributes |= DNS_RDATASETATTR_NCACHE; if (rctx->aa) { rdataset->trust = dns_trust_authauthority; } else if (ISFORWARDER(fctx->addrinfo)) { rdataset->trust = dns_trust_answer; } else { rdataset->trust = dns_trust_additional; } break; default: continue; } } } return ISC_R_SUCCESS; } /* * rctx_ncache(): * Cache the negatively cacheable parts of the message. This may * also cause work to be queued to the DNSSEC validator. */ static void rctx_ncache(respctx_t *rctx) { isc_result_t result; dns_rdatatype_t covers; fetchctx_t *fctx = rctx->fctx; if (!WANTNCACHE(fctx)) { return; } /* * Cache DS NXDOMAIN separately to other types. */ if (rctx->query->rmessage->rcode == dns_rcode_nxdomain && fctx->type != dns_rdatatype_ds) { covers = dns_rdatatype_any; } else { covers = fctx->type; } /* * Cache any negative cache entries in the message. */ result = ncache_message(fctx, rctx->query->rmessage, rctx->query->addrinfo, covers, rctx->now); if (result != ISC_R_SUCCESS) { FCTXTRACE3("ncache_message complete", result); } } /* * rctx_authority_dnssec(): * * Scan the authority section of a negative answer or referral, * handling DNSSEC records (i.e. NSEC, NSEC3, DS). */ static isc_result_t rctx_authority_dnssec(respctx_t *rctx) { isc_result_t result; fetchctx_t *fctx = rctx->fctx; dns_rdataset_t *rdataset = NULL; bool finished = false; REQUIRE(!rctx->ns_in_answer && !rctx->glue_in_answer); result = dns_message_firstname(rctx->query->rmessage, DNS_SECTION_AUTHORITY); if (result != ISC_R_SUCCESS) { return ISC_R_SUCCESS; } while (!finished) { dns_name_t *name = NULL; dns_message_currentname(rctx->query->rmessage, DNS_SECTION_AUTHORITY, &name); result = dns_message_nextname(rctx->query->rmessage, DNS_SECTION_AUTHORITY); if (result != ISC_R_SUCCESS) { finished = true; } if (!dns_name_issubdomain(name, fctx->domain)) { /* * Invalid name found; preserve it for logging * later. */ rctx->found_name = name; rctx->found_type = ISC_LIST_HEAD(name->list)->type; continue; } for (rdataset = ISC_LIST_HEAD(name->list); rdataset != NULL; rdataset = ISC_LIST_NEXT(rdataset, link)) { bool checknta = true; bool secure_domain = false; dns_rdatatype_t type = rdataset->type; if (type == dns_rdatatype_rrsig) { type = rdataset->covers; } switch (type) { case dns_rdatatype_nsec: case dns_rdatatype_nsec3: if (rctx->negative) { name->attributes.ncache = true; rdataset->attributes |= DNS_RDATASETATTR_NCACHE; } else if (type == dns_rdatatype_nsec) { name->attributes.cache = true; rdataset->attributes |= DNS_RDATASETATTR_CACHE; } if (rctx->aa) { rdataset->trust = dns_trust_authauthority; } else if (ISFORWARDER(fctx->addrinfo)) { rdataset->trust = dns_trust_answer; } else { rdataset->trust = dns_trust_additional; } /* * No additional data needs to be * marked. */ break; case dns_rdatatype_ds: /* * DS or SIG DS. * * These should only be here if this is * a referral, and there should only be * one DS RRset. */ if (rctx->ns_name == NULL) { log_formerr(fctx, "DS with no " "referral"); rctx->result = DNS_R_FORMERR; return ISC_R_COMPLETE; } if (rdataset->type == dns_rdatatype_ds) { if (rctx->ds_name != NULL && name != rctx->ds_name) { log_formerr(fctx, "DS doesn't " "match " "referral " "(NS)"); rctx->result = DNS_R_FORMERR; return ISC_R_COMPLETE; } rctx->ds_name = name; } name->attributes.cache = true; rdataset->attributes |= DNS_RDATASETATTR_CACHE; if ((fctx->options & DNS_FETCHOPT_NONTA) != 0) { checknta = false; } if (fctx->res->view->enablevalidation) { result = issecuredomain( fctx->res->view, name, dns_rdatatype_ds, fctx->now, checknta, NULL, &secure_domain); if (result != ISC_R_SUCCESS) { return result; } } if (secure_domain) { rdataset->trust = dns_trust_pending_answer; } else if (rctx->aa) { rdataset->trust = dns_trust_authauthority; } else if (ISFORWARDER(fctx->addrinfo)) { rdataset->trust = dns_trust_answer; } else { rdataset->trust = dns_trust_additional; } break; default: continue; } } } return ISC_R_SUCCESS; } /* * rctx_referral(): * Handles referral responses. Check for sanity, find glue as needed, * and update the fetch context to follow the delegation. */ static isc_result_t rctx_referral(respctx_t *rctx) { isc_result_t result; fetchctx_t *fctx = rctx->fctx; if (rctx->negative || rctx->ns_name == NULL) { return ISC_R_SUCCESS; } /* * We already know ns_name is a subdomain of fctx->domain. * If ns_name is equal to fctx->domain, we're not making * progress. We return DNS_R_FORMERR so that we'll keep * trying other servers. */ if (dns_name_equal(rctx->ns_name, fctx->domain)) { log_formerr(fctx, "non-improving referral"); rctx->result = DNS_R_FORMERR; return ISC_R_COMPLETE; } /* * If the referral name is not a parent of the query * name, consider the responder insane. */ if (!dns_name_issubdomain(fctx->name, rctx->ns_name)) { /* Logged twice */ log_formerr(fctx, "referral to non-parent"); FCTXTRACE("referral to non-parent"); rctx->result = DNS_R_FORMERR; return ISC_R_COMPLETE; } /* * Mark any additional data related to this rdataset. * It's important that we do this before we change the * query domain. */ INSIST(rctx->ns_rdataset != NULL); FCTX_ATTR_SET(fctx, FCTX_ATTR_GLUING); (void)dns_rdataset_additionaldata(rctx->ns_rdataset, rctx->ns_name, check_related, rctx); #if CHECK_FOR_GLUE_IN_ANSWER /* * Look in the answer section for "glue" that is incorrectly * returned as a answer. This is needed if the server also * minimizes the response size by not adding records to the * additional section that are in the answer section or if * the record gets dropped due to message size constraints. */ if (rctx->glue_in_answer && (fctx->type == dns_rdatatype_aaaa || fctx->type == dns_rdatatype_a)) { (void)dns_rdataset_additionaldata( rctx->ns_rdataset, rctx->ns_name, check_answer, fctx); } #endif /* if CHECK_FOR_GLUE_IN_ANSWER */ FCTX_ATTR_CLR(fctx, FCTX_ATTR_GLUING); /* * NS rdatasets with 0 TTL cause problems. * dns_view_findzonecut() will not find them when we * try to follow the referral, and we'll SERVFAIL * because the best nameservers are now above QDOMAIN. * We force the TTL to 1 second to prevent this. */ if (rctx->ns_rdataset->ttl == 0) { rctx->ns_rdataset->ttl = 1; } /* * Set the current query domain to the referral name. * * XXXRTH We should check if we're in forward-only mode, and * if so we should bail out. */ INSIST(dns_name_countlabels(fctx->domain) > 0); fcount_decr(fctx); if (dns_rdataset_isassociated(&fctx->nameservers)) { dns_rdataset_disassociate(&fctx->nameservers); } dns_name_copy(rctx->ns_name, fctx->domain); if ((fctx->options & DNS_FETCHOPT_QMINIMIZE) != 0) { dns_name_copy(rctx->ns_name, fctx->qmindcname); fctx_minimize_qname(fctx); } result = fcount_incr(fctx, true); if (result != ISC_R_SUCCESS) { rctx->result = result; return ISC_R_COMPLETE; } FCTX_ATTR_SET(fctx, FCTX_ATTR_WANTCACHE); fctx->ns_ttl_ok = false; log_ns_ttl(fctx, "DELEGATION"); rctx->result = DNS_R_DELEGATION; /* * Reinitialize 'rctx' to prepare for following the delegation: * set the get_nameservers and next_server flags appropriately * and reset the fetch context counters. * */ if ((rctx->fctx->options & DNS_FETCHOPT_NOFOLLOW) == 0) { rctx->get_nameservers = true; rctx->next_server = true; rctx->fctx->restarts = 0; rctx->fctx->referrals++; rctx->fctx->querysent = 0; rctx->fctx->lamecount = 0; rctx->fctx->quotacount = 0; rctx->fctx->neterr = 0; rctx->fctx->badresp = 0; rctx->fctx->adberr = 0; } return ISC_R_COMPLETE; } /* * rctx_additional(): * Scan the additional section of a response to find records related * to answers we were interested in. */ static void rctx_additional(respctx_t *rctx) { bool rescan; dns_section_t section = DNS_SECTION_ADDITIONAL; isc_result_t result; again: rescan = false; for (result = dns_message_firstname(rctx->query->rmessage, section); result == ISC_R_SUCCESS; result = dns_message_nextname(rctx->query->rmessage, section)) { dns_name_t *name = NULL; dns_rdataset_t *rdataset; dns_message_currentname(rctx->query->rmessage, DNS_SECTION_ADDITIONAL, &name); if (!name->attributes.chase) { continue; } name->attributes.chase = false; for (rdataset = ISC_LIST_HEAD(name->list); rdataset != NULL; rdataset = ISC_LIST_NEXT(rdataset, link)) { if (CHASE(rdataset)) { rdataset->attributes &= ~DNS_RDATASETATTR_CHASE; (void)dns_rdataset_additionaldata( rdataset, name, check_related, rctx); rescan = true; } } } if (rescan) { goto again; } } /* * rctx_nextserver(): * We found something wrong with the remote server, but it may be * useful to try another one. */ static void rctx_nextserver(respctx_t *rctx, dns_message_t *message, dns_adbaddrinfo_t *addrinfo, isc_result_t result) { fetchctx_t *fctx = rctx->fctx; bool retrying = true; if (result == DNS_R_FORMERR) { rctx->broken_server = DNS_R_FORMERR; } if (rctx->broken_server != ISC_R_SUCCESS) { /* * Add this server to the list of bad servers for * this fctx. */ add_bad(fctx, message, addrinfo, rctx->broken_server, rctx->broken_type); } if (rctx->get_nameservers) { dns_fixedname_t foundname, founddc; dns_name_t *name, *fname, *dcname; unsigned int findoptions = 0; fname = dns_fixedname_initname(&foundname); dcname = dns_fixedname_initname(&founddc); if (result != ISC_R_SUCCESS) { fctx_done_detach(&rctx->fctx, DNS_R_SERVFAIL); return; } if (dns_rdatatype_atparent(fctx->type)) { findoptions |= DNS_DBFIND_NOEXACT; } /* FIXME: Why??? */ if ((rctx->retryopts & DNS_FETCHOPT_UNSHARED) == 0) { name = fctx->name; } else { name = fctx->domain; } result = dns_view_findzonecut( fctx->res->view, name, fname, dcname, fctx->now, findoptions, true, true, &fctx->nameservers, NULL); if (result != ISC_R_SUCCESS) { FCTXTRACE("couldn't find a zonecut"); fctx_done_detach(&rctx->fctx, DNS_R_SERVFAIL); return; } if (!dns_name_issubdomain(fname, fctx->domain)) { /* * The best nameservers are now above our * QDOMAIN. */ FCTXTRACE("nameservers now above QDOMAIN"); fctx_done_detach(&rctx->fctx, DNS_R_SERVFAIL); return; } fcount_decr(fctx); dns_name_copy(fname, fctx->domain); dns_name_copy(dcname, fctx->qmindcname); result = fcount_incr(fctx, true); if (result != ISC_R_SUCCESS) { fctx_done_detach(&rctx->fctx, DNS_R_SERVFAIL); return; } fctx->ns_ttl = fctx->nameservers.ttl; fctx->ns_ttl_ok = true; fctx_cancelqueries(fctx, true, false); fctx_cleanup(fctx); retrying = false; } /* * Try again. */ fctx_try(fctx, retrying); } /* * rctx_resend(): * * Resend the query, probably with the options changed. Calls * fctx_query(), passing rctx->retryopts (which is based on * query->options, but may have been updated since the last time * fctx_query() was called). */ static void rctx_resend(respctx_t *rctx, dns_adbaddrinfo_t *addrinfo) { fetchctx_t *fctx = rctx->fctx; isc_result_t result; FCTXTRACE("resend"); inc_stats(fctx->res, dns_resstatscounter_retry); result = fctx_query(fctx, addrinfo, rctx->retryopts); if (result != ISC_R_SUCCESS) { fctx_done_detach(&rctx->fctx, result); } } /* * rctx_next(): * We got what appeared to be a response but it didn't match the * question or the cookie; it may have been meant for someone else, or * it may be a spoofing attack. Drop it and continue listening for the * response we wanted. */ static isc_result_t rctx_next(respctx_t *rctx) { fetchctx_t *fctx = rctx->fctx; isc_result_t result; FCTXTRACE("nextitem"); inc_stats(rctx->fctx->res, dns_resstatscounter_nextitem); INSIST(rctx->query->dispentry != NULL); dns_message_reset(rctx->query->rmessage, DNS_MESSAGE_INTENTPARSE); result = dns_dispatch_getnext(rctx->query->dispentry); return result; } /* * rctx_chaseds(): * Look up the parent zone's NS records so that DS records can be * fetched. */ static void rctx_chaseds(respctx_t *rctx, dns_message_t *message, dns_adbaddrinfo_t *addrinfo, isc_result_t result) { fetchctx_t *fctx = rctx->fctx; unsigned int n; add_bad(fctx, message, addrinfo, result, rctx->broken_type); fctx_cancelqueries(fctx, true, false); fctx_cleanup(fctx); n = dns_name_countlabels(fctx->name); dns_name_getlabelsequence(fctx->name, 1, n - 1, fctx->nsname); FCTXTRACE("suspending DS lookup to find parent's NS records"); fetchctx_ref(fctx); result = dns_resolver_createfetch( fctx->res, fctx->nsname, dns_rdatatype_ns, NULL, NULL, NULL, NULL, 0, fctx->options, 0, fctx->qc, fctx->loop, resume_dslookup, fctx, &fctx->nsrrset, NULL, &fctx->nsfetch); if (result != ISC_R_SUCCESS) { if (result == DNS_R_DUPLICATE) { result = DNS_R_SERVFAIL; } fctx_done_detach(&rctx->fctx, result); fetchctx_detach(&fctx); return; } } /* * rctx_done(): * This resolver query response is finished, either because we * encountered a problem or because we've gotten all the information * from it that we can. We either wait for another response, resend the * query to the same server, resend to a new server, or clean up and * shut down the fetch. */ static void rctx_done(respctx_t *rctx, isc_result_t result) { resquery_t *query = rctx->query; fetchctx_t *fctx = rctx->fctx; dns_adbaddrinfo_t *addrinfo = query->addrinfo; dns_message_t *message = NULL; /* * Need to attach to the message until the scope * of this function ends, since there are many places * where the message is used and/or may be destroyed * before this function ends. */ dns_message_attach(query->rmessage, &message); FCTXTRACE4("query canceled in rctx_done();", rctx->no_response ? "no response" : "responding", result); #ifdef ENABLE_AFL if (dns_fuzzing_resolver && (rctx->next_server || rctx->resend || rctx->nextitem)) { fctx_cancelquery(&query, rctx->finish, rctx->no_response, false); fctx_done_detach(&rctx->fctx, DNS_R_SERVFAIL); goto detach; } #endif /* ifdef ENABLE_AFL */ if (rctx->nextitem) { REQUIRE(!rctx->next_server); REQUIRE(!rctx->resend); result = rctx_next(rctx); if (result == ISC_R_SUCCESS) { goto detach; } } /* Cancel the query */ fctx_cancelquery(&query, rctx->finish, rctx->no_response, false); /* * If nobody's waiting for results, don't resend or try next server. */ LOCK(&fctx->lock); if (ISC_LIST_EMPTY(fctx->resps)) { rctx->next_server = false; rctx->resend = false; } UNLOCK(&fctx->lock); if (rctx->next_server) { rctx_nextserver(rctx, message, addrinfo, result); } else if (rctx->resend) { rctx_resend(rctx, addrinfo); } else if (result == DNS_R_CHASEDSSERVERS) { rctx_chaseds(rctx, message, addrinfo, result); } else if (result == ISC_R_SUCCESS && !HAVE_ANSWER(fctx)) { /* * All has gone well so far, but we are waiting for the DNSSEC * validator to validate the answer. */ FCTXTRACE("wait for validator"); fctx_cancelqueries(fctx, true, false); } else { /* * We're done. */ fctx_done_detach(&rctx->fctx, result); } detach: dns_message_detach(&message); } /* * rctx_logpacket(): * Log the incoming packet; also log to DNSTAP if configured. */ static void rctx_logpacket(respctx_t *rctx) { fetchctx_t *fctx = rctx->fctx; #ifdef HAVE_DNSTAP isc_result_t result; isc_sockaddr_t localaddr, *la = NULL; unsigned char zone[DNS_NAME_MAXWIRE]; dns_transport_type_t transport_type; dns_dtmsgtype_t dtmsgtype; dns_compress_t cctx; isc_region_t zr; isc_buffer_t zb; #endif /* HAVE_DNSTAP */ dns_message_logfmtpacket( rctx->query->rmessage, "received packet from", &rctx->query->addrinfo->sockaddr, DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_PACKETS, &dns_master_style_comment, ISC_LOG_DEBUG(10), fctx->mctx); #ifdef HAVE_DNSTAP /* * Log the response via dnstap. */ memset(&zr, 0, sizeof(zr)); dns_compress_init(&cctx, fctx->mctx, 0); dns_compress_setpermitted(&cctx, false); isc_buffer_init(&zb, zone, sizeof(zone)); result = dns_name_towire(fctx->domain, &cctx, &zb, NULL); if (result == ISC_R_SUCCESS) { isc_buffer_usedregion(&zb, &zr); } dns_compress_invalidate(&cctx); if ((fctx->qmessage->flags & DNS_MESSAGEFLAG_RD) != 0) { dtmsgtype = DNS_DTTYPE_FR; } else { dtmsgtype = DNS_DTTYPE_RR; } result = dns_dispentry_getlocaladdress(rctx->query->dispentry, &localaddr); if (result == ISC_R_SUCCESS) { la = &localaddr; } if (rctx->query->addrinfo->transport != NULL) { transport_type = dns_transport_get_type( rctx->query->addrinfo->transport); } else if ((rctx->query->options & DNS_FETCHOPT_TCP) != 0) { transport_type = DNS_TRANSPORT_TCP; } else { transport_type = DNS_TRANSPORT_UDP; } dns_dt_send(fctx->res->view, dtmsgtype, la, &rctx->query->addrinfo->sockaddr, transport_type, &zr, &rctx->query->start, NULL, &rctx->buffer); #endif /* HAVE_DNSTAP */ } /* * rctx_badserver(): * Is the remote server broken, or does it dislike us? */ static isc_result_t rctx_badserver(respctx_t *rctx, isc_result_t result) { fetchctx_t *fctx = rctx->fctx; resquery_t *query = rctx->query; isc_buffer_t b; char code[64]; dns_rcode_t rcode = rctx->query->rmessage->rcode; if (rcode == dns_rcode_noerror || rcode == dns_rcode_yxdomain || rcode == dns_rcode_nxdomain) { return ISC_R_SUCCESS; } if ((rcode == dns_rcode_formerr) && rctx->opt == NULL && (rctx->retryopts & DNS_FETCHOPT_NOEDNS0) == 0) { /* * It's very likely they don't like EDNS0. */ rctx->retryopts |= DNS_FETCHOPT_NOEDNS0; rctx->resend = true; /* * Remember that they may not like EDNS0. */ add_bad_edns(fctx, &query->addrinfo->sockaddr); inc_stats(fctx->res, dns_resstatscounter_edns0fail); } else if (rcode == dns_rcode_formerr) { if (query->rmessage->cc_echoed) { /* * Retry without DNS COOKIE. */ query->addrinfo->flags |= FCTX_ADDRINFO_NOCOOKIE; rctx->resend = true; log_formerr(fctx, "server sent FORMERR with echoed DNS " "COOKIE"); } else { /* * The server (or forwarder) doesn't understand us, * but others might. */ rctx->next_server = true; rctx->broken_server = DNS_R_REMOTEFORMERR; log_formerr(fctx, "server sent FORMERR"); } } else if (rcode == dns_rcode_badvers) { unsigned int version; #if DNS_EDNS_VERSION > 0 unsigned int flags, mask; #endif /* if DNS_EDNS_VERSION > 0 */ INSIST(rctx->opt != NULL); version = (rctx->opt->ttl >> 16) & 0xff; #if DNS_EDNS_VERSION > 0 flags = (version << DNS_FETCHOPT_EDNSVERSIONSHIFT) | DNS_FETCHOPT_EDNSVERSIONSET; mask = DNS_FETCHOPT_EDNSVERSIONMASK | DNS_FETCHOPT_EDNSVERSIONSET; #endif /* if DNS_EDNS_VERSION > 0 */ /* * Record that we got a good EDNS response. */ if (query->ednsversion > (int)version && !EDNSOK(query->addrinfo)) { dns_adb_changeflags(fctx->adb, query->addrinfo, FCTX_ADDRINFO_EDNSOK, FCTX_ADDRINFO_EDNSOK); } /* * RFC 2671 was not clear that unknown options should * be ignored. RFC 6891 is clear that that they * should be ignored. If we are supporting the * experimental EDNS > 0 then perform strict * version checking of badvers responses. We won't * be sending COOKIE etc. in that case. */ #if DNS_EDNS_VERSION > 0 if ((int)version < query->ednsversion) { dns_adb_changeflags(fctx->adb, query->addrinfo, flags, mask); rctx->resend = true; } else { rctx->broken_server = DNS_R_BADVERS; rctx->next_server = true; } #else /* if DNS_EDNS_VERSION > 0 */ rctx->broken_server = DNS_R_BADVERS; rctx->next_server = true; #endif /* if DNS_EDNS_VERSION > 0 */ } else if (rcode == dns_rcode_badcookie && rctx->query->rmessage->cc_ok) { /* * We have recorded the new cookie. */ if (BADCOOKIE(query->addrinfo)) { rctx->retryopts |= DNS_FETCHOPT_TCP; } query->addrinfo->flags |= FCTX_ADDRINFO_BADCOOKIE; rctx->resend = true; } else { rctx->broken_server = DNS_R_UNEXPECTEDRCODE; rctx->next_server = true; } isc_buffer_init(&b, code, sizeof(code) - 1); dns_rcode_totext(rcode, &b); code[isc_buffer_usedlength(&b)] = '\0'; FCTXTRACE2("remote server broken: returned ", code); rctx_done(rctx, result); return ISC_R_COMPLETE; } /* * rctx_lameserver(): * Is the server lame? */ static isc_result_t rctx_lameserver(respctx_t *rctx) { isc_result_t result = ISC_R_SUCCESS; fetchctx_t *fctx = rctx->fctx; resquery_t *query = rctx->query; if (ISFORWARDER(query->addrinfo) || !is_lame(fctx, query->rmessage)) { return ISC_R_SUCCESS; } inc_stats(fctx->res, dns_resstatscounter_lame); log_lame(fctx, query->addrinfo); rctx->broken_server = DNS_R_LAME; rctx->next_server = true; FCTXTRACE("lame server"); rctx_done(rctx, result); return ISC_R_COMPLETE; } /*** *** Resolver Methods ***/ static void dns_resolver__destroy(dns_resolver_t *res) { alternate_t *a = NULL; REQUIRE(!atomic_load_acquire(&res->priming)); REQUIRE(res->primefetch == NULL); RTRACE("destroy"); REQUIRE(atomic_load_acquire(&res->nfctx) == 0); res->magic = 0; dns_nametree_detach(&res->algorithms); dns_nametree_detach(&res->digests); dns_nametree_detach(&res->mustbesecure); if (res->querystats != NULL) { dns_stats_detach(&res->querystats); } if (res->stats != NULL) { isc_stats_detach(&res->stats); } isc_mutex_destroy(&res->primelock); isc_mutex_destroy(&res->lock); INSIST(isc_hashmap_count(res->fctxs) == 0); isc_hashmap_destroy(&res->fctxs); isc_rwlock_destroy(&res->fctxs_lock); INSIST(isc_hashmap_count(res->counters) == 0); isc_hashmap_destroy(&res->counters); isc_rwlock_destroy(&res->counters_lock); if (res->dispatches4 != NULL) { dns_dispatchset_destroy(&res->dispatches4); } if (res->dispatches6 != NULL) { dns_dispatchset_destroy(&res->dispatches6); } while ((a = ISC_LIST_HEAD(res->alternates)) != NULL) { ISC_LIST_UNLINK(res->alternates, a, link); if (!a->isaddress) { dns_name_free(&a->_u._n.name, res->mctx); } isc_mem_put(res->mctx, a, sizeof(*a)); } dns_view_weakdetach(&res->view); for (size_t i = 0; i < res->nloops; i++) { dns_message_destroypools(&res->namepools[i], &res->rdspools[i]); } isc_mem_cput(res->mctx, res->rdspools, res->nloops, sizeof(res->rdspools[0])); isc_mem_cput(res->mctx, res->namepools, res->nloops, sizeof(res->namepools[0])); isc_mem_putanddetach(&res->mctx, res, sizeof(*res)); } static void spillattimer_countdown(void *arg) { dns_resolver_t *res = (dns_resolver_t *)arg; unsigned int spillat = 0; REQUIRE(VALID_RESOLVER(res)); if (atomic_load(&res->exiting)) { isc_timer_destroy(&res->spillattimer); return; } LOCK(&res->lock); INSIST(!atomic_load_acquire(&res->exiting)); if (res->spillat > res->spillatmin) { spillat = --res->spillat; } if (res->spillat <= res->spillatmin) { isc_timer_destroy(&res->spillattimer); } UNLOCK(&res->lock); if (spillat > 0) { isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER, ISC_LOG_NOTICE, "clients-per-query decreased to %u", spillat); } } isc_result_t dns_resolver_create(dns_view_t *view, isc_loopmgr_t *loopmgr, isc_nm_t *nm, unsigned int options, isc_tlsctx_cache_t *tlsctx_cache, dns_dispatch_t *dispatchv4, dns_dispatch_t *dispatchv6, dns_resolver_t **resp) { dns_resolver_t *res = NULL; /* * Create a resolver. */ REQUIRE(DNS_VIEW_VALID(view)); REQUIRE(resp != NULL && *resp == NULL); REQUIRE(tlsctx_cache != NULL); REQUIRE(dispatchv4 != NULL || dispatchv6 != NULL); res = isc_mem_get(view->mctx, sizeof(*res)); *res = (dns_resolver_t){ .loopmgr = loopmgr, .rdclass = view->rdclass, .nm = nm, .options = options, .tlsctx_cache = tlsctx_cache, .spillatmin = 10, .spillat = 10, .spillatmax = 100, .retryinterval = 800, .nonbackofftries = 3, .query_timeout = DEFAULT_QUERY_TIMEOUT, .maxdepth = DEFAULT_RECURSION_DEPTH, .maxqueries = DEFAULT_MAX_QUERIES, .alternates = ISC_LIST_INITIALIZER, .nloops = isc_loopmgr_nloops(loopmgr), .maxvalidations = DEFAULT_MAX_VALIDATIONS, .maxvalidationfails = DEFAULT_MAX_VALIDATION_FAILURES, }; RTRACE("create"); dns_view_weakattach(view, &res->view); isc_mem_attach(view->mctx, &res->mctx); res->quotaresp[dns_quotatype_zone] = DNS_R_DROP; res->quotaresp[dns_quotatype_server] = DNS_R_SERVFAIL; #if DNS_RESOLVER_TRACE fprintf(stderr, "dns_resolver__init:%s:%s:%d:%p->references = 1\n", __func__, __FILE__, __LINE__, res); #endif isc_refcount_init(&res->references, 1); isc_hashmap_create(view->mctx, RES_DOMAIN_HASH_BITS, &res->fctxs); isc_rwlock_init(&res->fctxs_lock); isc_hashmap_create(view->mctx, RES_DOMAIN_HASH_BITS, &res->counters); isc_rwlock_init(&res->counters_lock); if (dispatchv4 != NULL) { dns_dispatchset_create(res->mctx, dispatchv4, &res->dispatches4, res->nloops); } if (dispatchv6 != NULL) { dns_dispatchset_create(res->mctx, dispatchv6, &res->dispatches6, res->nloops); } isc_mutex_init(&res->lock); isc_mutex_init(&res->primelock); dns_nametree_create(res->mctx, DNS_NAMETREE_BITS, "algorithms", &res->algorithms); dns_nametree_create(res->mctx, DNS_NAMETREE_BITS, "ds-digests", &res->digests); dns_nametree_create(res->mctx, DNS_NAMETREE_BOOL, "dnssec-must-be-secure", &res->mustbesecure); res->namepools = isc_mem_cget(res->mctx, res->nloops, sizeof(res->namepools[0])); res->rdspools = isc_mem_cget(res->mctx, res->nloops, sizeof(res->rdspools[0])); for (size_t i = 0; i < res->nloops; i++) { isc_loop_t *loop = isc_loop_get(res->loopmgr, i); isc_mem_t *pool_mctx = isc_loop_getmctx(loop); dns_message_createpools(pool_mctx, &res->namepools[i], &res->rdspools[i]); } res->magic = RES_MAGIC; *resp = res; return ISC_R_SUCCESS; } static void prime_done(void *arg) { dns_fetchresponse_t *resp = (dns_fetchresponse_t *)arg; dns_resolver_t *res = resp->arg; dns_fetch_t *fetch = NULL; dns_db_t *db = NULL; REQUIRE(VALID_RESOLVER(res)); int level = (resp->result == ISC_R_SUCCESS) ? ISC_LOG_DEBUG(1) : ISC_LOG_NOTICE; isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER, level, "resolver priming query complete: %s", isc_result_totext(resp->result)); LOCK(&res->primelock); fetch = res->primefetch; res->primefetch = NULL; UNLOCK(&res->primelock); atomic_compare_exchange_enforced(&res->priming, &(bool){ true }, false); if (resp->result == ISC_R_SUCCESS && res->view->cache != NULL && res->view->hints != NULL) { dns_cache_attachdb(res->view->cache, &db); dns_root_checkhints(res->view, res->view->hints, db); dns_db_detach(&db); } if (resp->node != NULL) { dns_db_detachnode(resp->db, &resp->node); } if (resp->db != NULL) { dns_db_detach(&resp->db); } if (dns_rdataset_isassociated(resp->rdataset)) { dns_rdataset_disassociate(resp->rdataset); } INSIST(resp->sigrdataset == NULL); isc_mem_put(res->mctx, resp->rdataset, sizeof(*resp->rdataset)); isc_mem_putanddetach(&resp->mctx, resp, sizeof(*resp)); dns_resolver_destroyfetch(&fetch); } void dns_resolver_prime(dns_resolver_t *res) { bool want_priming = false; isc_result_t result; REQUIRE(VALID_RESOLVER(res)); REQUIRE(res->frozen); RTRACE("dns_resolver_prime"); if (!atomic_load_acquire(&res->exiting)) { want_priming = atomic_compare_exchange_strong_acq_rel( &res->priming, &(bool){ false }, true); } if (want_priming) { /* * To avoid any possible recursive locking problems, we * start the priming fetch like any other fetch, and * holding no resolver locks. No one else will try to * start it because we're the ones who set res->priming * to true. Any other callers of dns_resolver_prime() * while we're running will see that res->priming is * already true and do nothing. */ RTRACE("priming"); dns_rdataset_t *rdataset = isc_mem_get(res->mctx, sizeof(*rdataset)); dns_rdataset_init(rdataset); LOCK(&res->primelock); result = dns_resolver_createfetch( res, dns_rootname, dns_rdatatype_ns, NULL, NULL, NULL, NULL, 0, DNS_FETCHOPT_NOFORWARD, 0, NULL, isc_loop(), prime_done, res, rdataset, NULL, &res->primefetch); UNLOCK(&res->primelock); if (result != ISC_R_SUCCESS) { isc_mem_put(res->mctx, rdataset, sizeof(*rdataset)); atomic_compare_exchange_enforced( &res->priming, &(bool){ true }, false); } inc_stats(res, dns_resstatscounter_priming); } } void dns_resolver_freeze(dns_resolver_t *res) { /* * Freeze resolver. */ REQUIRE(VALID_RESOLVER(res)); res->frozen = true; } void dns_resolver_shutdown(dns_resolver_t *res) { isc_result_t result; bool is_false = false; REQUIRE(VALID_RESOLVER(res)); RTRACE("shutdown"); if (atomic_compare_exchange_strong(&res->exiting, &is_false, true)) { isc_hashmap_iter_t *it = NULL; RTRACE("exiting"); RWLOCK(&res->fctxs_lock, isc_rwlocktype_write); isc_hashmap_iter_create(res->fctxs, &it); for (result = isc_hashmap_iter_first(it); result == ISC_R_SUCCESS; result = isc_hashmap_iter_next(it)) { fetchctx_t *fctx = NULL; isc_hashmap_iter_current(it, (void **)&fctx); INSIST(fctx != NULL); fetchctx_ref(fctx); isc_async_run(fctx->loop, fctx_shutdown, fctx); } isc_hashmap_iter_destroy(&it); RWUNLOCK(&res->fctxs_lock, isc_rwlocktype_write); LOCK(&res->lock); if (res->spillattimer != NULL) { isc_timer_async_destroy(&res->spillattimer); } UNLOCK(&res->lock); } } #if DNS_RESOLVER_TRACE ISC_REFCOUNT_TRACE_IMPL(dns_resolver, dns_resolver__destroy); #else ISC_REFCOUNT_IMPL(dns_resolver, dns_resolver__destroy); #endif static void log_fetch(const dns_name_t *name, dns_rdatatype_t type) { char namebuf[DNS_NAME_FORMATSIZE]; char typebuf[DNS_RDATATYPE_FORMATSIZE]; int level = ISC_LOG_DEBUG(1); /* * If there's no chance of logging it, don't render (format) the * name and RDATA type (further below), and return early. */ if (!isc_log_wouldlog(dns_lctx, level)) { return; } dns_name_format(name, namebuf, sizeof(namebuf)); dns_rdatatype_format(type, typebuf, sizeof(typebuf)); isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER, level, "fetch: %s/%s", namebuf, typebuf); } static void fctx_minimize_qname(fetchctx_t *fctx) { isc_result_t result; unsigned int dlabels, nlabels; dns_name_t name; REQUIRE(VALID_FCTX(fctx)); dns_name_init(&name, NULL); dlabels = dns_name_countlabels(fctx->qmindcname); nlabels = dns_name_countlabels(fctx->name); if (dlabels > fctx->qmin_labels) { fctx->qmin_labels = dlabels + 1; } else { fctx->qmin_labels++; } if (fctx->ip6arpaskip) { /* * For ip6.arpa we want to skip some of the labels, with * boundaries at /16, /32, /48, /56, /64 and /128 * In 'label count' terms that's equal to * 7 11 15 17 19 35 * We fix fctx->qmin_labels to point to the nearest * boundary */ if (fctx->qmin_labels < 7) { fctx->qmin_labels = 7; } else if (fctx->qmin_labels < 11) { fctx->qmin_labels = 11; } else if (fctx->qmin_labels < 15) { fctx->qmin_labels = 15; } else if (fctx->qmin_labels < 17) { fctx->qmin_labels = 17; } else if (fctx->qmin_labels < 19) { fctx->qmin_labels = 19; } else if (fctx->qmin_labels < 35) { fctx->qmin_labels = 35; } else { fctx->qmin_labels = nlabels; } } else if (fctx->qmin_labels > DNS_QMIN_MAXLABELS) { fctx->qmin_labels = DNS_NAME_MAXLABELS; } if (fctx->qmin_labels < nlabels) { dns_rdataset_t rdataset; dns_fixedname_t fixed; dns_name_t *fname = dns_fixedname_initname(&fixed); dns_rdataset_init(&rdataset); do { /* * We want to query for qmin_labels from fctx->name. */ dns_name_split(fctx->name, fctx->qmin_labels, NULL, &name); /* * Look to see if we have anything cached about NS * RRsets at this name and if so skip this name and * try with an additional label prepended. */ result = dns_db_find(fctx->cache, &name, NULL, dns_rdatatype_ns, 0, 0, NULL, fname, &rdataset, NULL); if (dns_rdataset_isassociated(&rdataset)) { dns_rdataset_disassociate(&rdataset); } switch (result) { case ISC_R_SUCCESS: case DNS_R_CNAME: case DNS_R_DNAME: case DNS_R_NCACHENXDOMAIN: case DNS_R_NCACHENXRRSET: fctx->qmin_labels++; continue; default: break; } break; } while (fctx->qmin_labels < nlabels); } if (fctx->qmin_labels < nlabels) { dns_name_copy(&name, fctx->qminname); fctx->qmintype = dns_rdatatype_ns; fctx->minimized = true; } else { /* Minimization is done, we'll ask for whole qname */ dns_name_copy(fctx->name, fctx->qminname); fctx->qmintype = fctx->type; fctx->minimized = false; } char domainbuf[DNS_NAME_FORMATSIZE]; dns_name_format(fctx->qminname, domainbuf, sizeof(domainbuf)); isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER, ISC_LOG_DEBUG(5), "QNAME minimization - %s minimized, qmintype %d " "qminname %s", fctx->minimized ? "" : "not", fctx->qmintype, domainbuf); } static isc_result_t get_attached_fctx(dns_resolver_t *res, isc_loop_t *loop, const dns_name_t *name, dns_rdatatype_t type, const dns_name_t *domain, dns_rdataset_t *nameservers, const isc_sockaddr_t *client, unsigned int options, unsigned int depth, isc_counter_t *qc, fetchctx_t **fctxp, bool *new_fctx) { isc_result_t result; fetchctx_t key = { .name = UNCONST(name), .options = options, .type = type, }; fetchctx_t *fctx = NULL; isc_rwlocktype_t locktype = isc_rwlocktype_read; uint32_t hashval = fctx_hash(&key); again: RWLOCK(&res->fctxs_lock, locktype); result = isc_hashmap_find(res->fctxs, hashval, fctx_match, &key, (void **)&fctx); switch (result) { case ISC_R_SUCCESS: break; case ISC_R_NOTFOUND: result = fctx_create(res, loop, name, type, domain, nameservers, client, options, depth, qc, &fctx); if (result != ISC_R_SUCCESS) { goto unlock; } UPGRADELOCK(&res->fctxs_lock, locktype); void *found = NULL; result = isc_hashmap_add(res->fctxs, hashval, fctx_match, fctx, fctx, &found); if (result == ISC_R_SUCCESS) { *new_fctx = true; fctx->hashed = true; } else { fctx_done_detach(&fctx, result); fctx = found; result = ISC_R_SUCCESS; } INSIST(result == ISC_R_SUCCESS); break; default: UNREACHABLE(); } fetchctx_ref(fctx); unlock: RWUNLOCK(&res->fctxs_lock, locktype); if (result == ISC_R_SUCCESS) { LOCK(&fctx->lock); if (SHUTTINGDOWN(fctx) || fctx->cloned) { /* * This is the single place where fctx might get * accesses from a different thread, so we need to * double check whether fctxs is done (or cloned) and * help with the release if the fctx has been cloned. */ release_fctx(fctx); UNLOCK(&fctx->lock); fetchctx_detach(&fctx); goto again; } INSIST(!SHUTTINGDOWN(fctx)); *fctxp = fctx; } return result; } isc_result_t dns_resolver_createfetch(dns_resolver_t *res, const dns_name_t *name, dns_rdatatype_t type, const dns_name_t *domain, dns_rdataset_t *nameservers, dns_forwarders_t *forwarders, const isc_sockaddr_t *client, dns_messageid_t id, unsigned int options, unsigned int depth, isc_counter_t *qc, isc_loop_t *loop, isc_job_cb cb, void *arg, dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset, dns_fetch_t **fetchp) { dns_fetch_t *fetch = NULL; fetchctx_t *fctx = NULL; isc_result_t result = ISC_R_SUCCESS; bool new_fctx = false; unsigned int count = 0; unsigned int spillat; unsigned int spillatmin; isc_mem_t *mctx = isc_loop_getmctx(loop); UNUSED(forwarders); REQUIRE(VALID_RESOLVER(res)); REQUIRE(res->frozen); /* XXXRTH Check for meta type */ if (domain != NULL) { REQUIRE(DNS_RDATASET_VALID(nameservers)); REQUIRE(nameservers->type == dns_rdatatype_ns); } else { REQUIRE(nameservers == NULL); } REQUIRE(forwarders == NULL); REQUIRE(!dns_rdataset_isassociated(rdataset)); REQUIRE(sigrdataset == NULL || !dns_rdataset_isassociated(sigrdataset)); REQUIRE(fetchp != NULL && *fetchp == NULL); if (atomic_load_acquire(&res->exiting)) { return ISC_R_SHUTTINGDOWN; } log_fetch(name, type); fetch = isc_mem_get(mctx, sizeof(*fetch)); *fetch = (dns_fetch_t){ 0 }; dns_resolver_attach(res, &fetch->res); isc_mem_attach(mctx, &fetch->mctx); if ((options & DNS_FETCHOPT_UNSHARED) == 0) { /* * We don't save the unshared fetch context to a bucket because * we also would never match it again. */ LOCK(&res->lock); spillat = res->spillat; spillatmin = res->spillatmin; UNLOCK(&res->lock); result = get_attached_fctx(res, loop, name, type, domain, nameservers, client, options, depth, qc, &fctx, &new_fctx); if (result != ISC_R_SUCCESS) { goto fail; } /* On success, the fctx is locked in get_attached_fctx() */ INSIST(!SHUTTINGDOWN(fctx)); /* Is this a duplicate? */ if (client != NULL) { dns_fetchresponse_t *resp = NULL; for (resp = ISC_LIST_HEAD(fctx->resps); resp != NULL; resp = ISC_LIST_NEXT(resp, link)) { if (resp->client != NULL && resp->id == id && isc_sockaddr_equal(resp->client, client)) { result = DNS_R_DUPLICATE; goto unlock; } count++; } } if (count >= spillatmin && spillatmin != 0) { if (count >= spillat) { fctx->spilled = true; } if (fctx->spilled) { inc_stats(res, dns_resstatscounter_clientquota); result = DNS_R_DROP; goto unlock; } } } else { result = fctx_create(res, loop, name, type, domain, nameservers, client, options, depth, qc, &fctx); if (result != ISC_R_SUCCESS) { goto unlock; } new_fctx = true; } RUNTIME_CHECK(fctx != NULL); if (fctx->depth > depth) { fctx->depth = depth; } fctx_join(fctx, loop, client, id, cb, arg, rdataset, sigrdataset, fetch); if (new_fctx) { fetchctx_ref(fctx); isc_async_run(fctx->loop, fctx_start, fctx); } unlock: if ((options & DNS_FETCHOPT_UNSHARED) == 0) { UNLOCK(&fctx->lock); fetchctx_unref(fctx); } fail: if (result != ISC_R_SUCCESS) { dns_resolver_detach(&fetch->res); isc_mem_putanddetach(&fetch->mctx, fetch, sizeof(*fetch)); return result; } FTRACE("created"); *fetchp = fetch; return ISC_R_SUCCESS; } void dns_resolver_cancelfetch(dns_fetch_t *fetch) { fetchctx_t *fctx = NULL; REQUIRE(DNS_FETCH_VALID(fetch)); fctx = fetch->private; REQUIRE(VALID_FCTX(fctx)); FTRACE("cancelfetch"); LOCK(&fctx->lock); /* * Find the completion event associated with this fetch (as opposed * to those for other fetches that have joined the same fctx) and run * the callback asynchronously with a ISC_R_CANCELED result. */ if (fctx->state != fetchstate_done) { dns_fetchresponse_t *next = NULL; for (dns_fetchresponse_t *resp = ISC_LIST_HEAD(fctx->resps); resp != NULL; resp = next) { next = ISC_LIST_NEXT(resp, link); if (resp->fetch == fetch) { resp->result = ISC_R_CANCELED; ISC_LIST_UNLINK(fctx->resps, resp, link); isc_async_run(resp->loop, resp->cb, resp); break; } } } /* * The fctx continues running even if no fetches remain; * the answer is still cached. */ UNLOCK(&fctx->lock); } void dns_resolver_destroyfetch(dns_fetch_t **fetchp) { dns_fetch_t *fetch = NULL; dns_resolver_t *res = NULL; fetchctx_t *fctx = NULL; REQUIRE(fetchp != NULL); fetch = *fetchp; *fetchp = NULL; REQUIRE(DNS_FETCH_VALID(fetch)); fctx = fetch->private; REQUIRE(VALID_FCTX(fctx)); res = fetch->res; FTRACE("destroyfetch"); fetch->magic = 0; LOCK(&fctx->lock); /* * Sanity check: the caller should have gotten its event before * trying to destroy the fetch. */ if (fctx->state != fetchstate_done) { dns_fetchresponse_t *resp = NULL, *next = NULL; for (resp = ISC_LIST_HEAD(fctx->resps); resp != NULL; resp = next) { next = ISC_LIST_NEXT(resp, link); RUNTIME_CHECK(resp->fetch != fetch); } } UNLOCK(&fctx->lock); isc_mem_putanddetach(&fetch->mctx, fetch, sizeof(*fetch)); fetchctx_detach(&fctx); dns_resolver_detach(&res); } void dns_resolver_logfetch(dns_fetch_t *fetch, isc_log_t *lctx, isc_logcategory_t *category, isc_logmodule_t *module, int level, bool duplicateok) { fetchctx_t *fctx = NULL; REQUIRE(DNS_FETCH_VALID(fetch)); fctx = fetch->private; REQUIRE(VALID_FCTX(fctx)); LOCK(&fctx->lock); if (!fctx->logged || duplicateok) { char domainbuf[DNS_NAME_FORMATSIZE]; dns_name_format(fctx->domain, domainbuf, sizeof(domainbuf)); isc_log_write(lctx, category, module, level, "fetch completed for %s in " "%" PRIu64 "." "%06" PRIu64 ": %s/%s " "[domain:%s,referral:%u,restart:%u,qrysent:%u," "timeout:%u,lame:%u,quota:%u,neterr:%u," "badresp:%u,adberr:%u,findfail:%u,valfail:%u]", fctx->info, fctx->duration / US_PER_SEC, fctx->duration % US_PER_SEC, isc_result_totext(fctx->result), isc_result_totext(fctx->vresult), domainbuf, fctx->referrals, fctx->restarts, fctx->querysent, fctx->timeouts, fctx->lamecount, fctx->quotacount, fctx->neterr, fctx->badresp, fctx->adberr, fctx->findfail, fctx->valfail); fctx->logged = true; } UNLOCK(&fctx->lock); } dns_dispatch_t * dns_resolver_dispatchv4(dns_resolver_t *resolver) { REQUIRE(VALID_RESOLVER(resolver)); return dns_dispatchset_get(resolver->dispatches4); } dns_dispatch_t * dns_resolver_dispatchv6(dns_resolver_t *resolver) { REQUIRE(VALID_RESOLVER(resolver)); return dns_dispatchset_get(resolver->dispatches6); } void dns_resolver_addalternate(dns_resolver_t *res, const isc_sockaddr_t *alt, const dns_name_t *name, in_port_t port) { alternate_t *a; REQUIRE(VALID_RESOLVER(res)); REQUIRE(!res->frozen); REQUIRE((alt == NULL) ^ (name == NULL)); a = isc_mem_get(res->mctx, sizeof(*a)); if (alt != NULL) { a->isaddress = true; a->_u.addr = *alt; } else { a->isaddress = false; a->_u._n.port = port; dns_name_init(&a->_u._n.name, NULL); dns_name_dup(name, res->mctx, &a->_u._n.name); } ISC_LINK_INIT(a, link); ISC_LIST_APPEND(res->alternates, a, link); } isc_result_t dns_resolver_disable_algorithm(dns_resolver_t *resolver, const dns_name_t *name, unsigned int alg) { REQUIRE(VALID_RESOLVER(resolver)); if (alg > 255) { return ISC_R_RANGE; } return dns_nametree_add(resolver->algorithms, name, alg); } isc_result_t dns_resolver_disable_ds_digest(dns_resolver_t *resolver, const dns_name_t *name, unsigned int digest_type) { REQUIRE(VALID_RESOLVER(resolver)); if (digest_type > 255) { return ISC_R_RANGE; } return dns_nametree_add(resolver->digests, name, digest_type); } bool dns_resolver_algorithm_supported(dns_resolver_t *resolver, const dns_name_t *name, unsigned int alg) { REQUIRE(VALID_RESOLVER(resolver)); if ((alg == DST_ALG_DH) || (alg == DST_ALG_INDIRECT)) { return false; } if (dns_nametree_covered(resolver->algorithms, name, NULL, alg)) { return false; } return dst_algorithm_supported(alg); } bool dns_resolver_ds_digest_supported(dns_resolver_t *resolver, const dns_name_t *name, unsigned int digest_type) { REQUIRE(VALID_RESOLVER(resolver)); if (dns_nametree_covered(resolver->digests, name, NULL, digest_type)) { return false; } return dst_ds_digest_supported(digest_type); } isc_result_t dns_resolver_setmustbesecure(dns_resolver_t *resolver, const dns_name_t *name, bool value) { isc_result_t result; REQUIRE(VALID_RESOLVER(resolver)); result = dns_nametree_add(resolver->mustbesecure, name, value); return result; } bool dns_resolver_getmustbesecure(dns_resolver_t *resolver, const dns_name_t *name) { REQUIRE(VALID_RESOLVER(resolver)); return dns_nametree_covered(resolver->mustbesecure, name, NULL, 0); } void dns_resolver_getclientsperquery(dns_resolver_t *resolver, uint32_t *cur, uint32_t *min, uint32_t *max) { REQUIRE(VALID_RESOLVER(resolver)); LOCK(&resolver->lock); SET_IF_NOT_NULL(cur, resolver->spillat); SET_IF_NOT_NULL(min, resolver->spillatmin); SET_IF_NOT_NULL(max, resolver->spillatmax); UNLOCK(&resolver->lock); } void dns_resolver_setclientsperquery(dns_resolver_t *resolver, uint32_t min, uint32_t max) { REQUIRE(VALID_RESOLVER(resolver)); LOCK(&resolver->lock); resolver->spillatmin = resolver->spillat = min; resolver->spillatmax = max; UNLOCK(&resolver->lock); } void dns_resolver_setfetchesperzone(dns_resolver_t *resolver, uint32_t clients) { REQUIRE(VALID_RESOLVER(resolver)); atomic_store_release(&resolver->zspill, clients); } uint32_t dns_resolver_getfetchesperzone(dns_resolver_t *resolver) { REQUIRE(VALID_RESOLVER(resolver)); return atomic_load_relaxed(&resolver->zspill); } bool dns_resolver_getzeronosoattl(dns_resolver_t *resolver) { REQUIRE(VALID_RESOLVER(resolver)); return resolver->zero_no_soa_ttl; } void dns_resolver_setzeronosoattl(dns_resolver_t *resolver, bool state) { REQUIRE(VALID_RESOLVER(resolver)); resolver->zero_no_soa_ttl = state; } unsigned int dns_resolver_getoptions(dns_resolver_t *resolver) { REQUIRE(VALID_RESOLVER(resolver)); return resolver->options; } unsigned int dns_resolver_gettimeout(dns_resolver_t *resolver) { REQUIRE(VALID_RESOLVER(resolver)); return resolver->query_timeout; } void dns_resolver_settimeout(dns_resolver_t *resolver, unsigned int timeout) { REQUIRE(VALID_RESOLVER(resolver)); if (timeout < MINIMUM_QUERY_TIMEOUT) { timeout *= 1000; } if (timeout == 0) { timeout = DEFAULT_QUERY_TIMEOUT; } if (timeout > MAXIMUM_QUERY_TIMEOUT) { timeout = MAXIMUM_QUERY_TIMEOUT; } if (timeout < MINIMUM_QUERY_TIMEOUT) { timeout = MINIMUM_QUERY_TIMEOUT; } resolver->query_timeout = timeout; } void dns_resolver_setmaxvalidations(dns_resolver_t *resolver, uint32_t max) { REQUIRE(VALID_RESOLVER(resolver)); atomic_store(&resolver->maxvalidations, max); } void dns_resolver_setmaxvalidationfails(dns_resolver_t *resolver, uint32_t max) { REQUIRE(VALID_RESOLVER(resolver)); atomic_store(&resolver->maxvalidationfails, max); } void dns_resolver_setmaxdepth(dns_resolver_t *resolver, unsigned int maxdepth) { REQUIRE(VALID_RESOLVER(resolver)); resolver->maxdepth = maxdepth; } unsigned int dns_resolver_getmaxdepth(dns_resolver_t *resolver) { REQUIRE(VALID_RESOLVER(resolver)); return resolver->maxdepth; } void dns_resolver_setmaxqueries(dns_resolver_t *resolver, unsigned int queries) { REQUIRE(VALID_RESOLVER(resolver)); resolver->maxqueries = queries; } unsigned int dns_resolver_getmaxqueries(dns_resolver_t *resolver) { REQUIRE(VALID_RESOLVER(resolver)); return resolver->maxqueries; } void dns_resolver_dumpfetches(dns_resolver_t *res, isc_statsformat_t format, FILE *fp) { isc_result_t result; isc_hashmap_iter_t *it = NULL; REQUIRE(VALID_RESOLVER(res)); REQUIRE(fp != NULL); REQUIRE(format == isc_statsformat_file); RWLOCK(&res->counters_lock, isc_rwlocktype_read); isc_hashmap_iter_create(res->counters, &it); for (result = isc_hashmap_iter_first(it); result == ISC_R_SUCCESS; result = isc_hashmap_iter_next(it)) { fctxcount_t *counter = NULL; isc_hashmap_iter_current(it, (void **)&counter); dns_name_print(counter->domain, fp); fprintf(fp, ": %" PRIuFAST32 " active (%" PRIuFAST32 " spilled, %" PRIuFAST32 " allowed)\n", counter->count, counter->dropped, counter->allowed); } RWUNLOCK(&res->counters_lock, isc_rwlocktype_read); isc_hashmap_iter_destroy(&it); } isc_result_t dns_resolver_dumpquota(dns_resolver_t *res, isc_buffer_t **buf) { isc_result_t result; isc_hashmap_iter_t *it = NULL; uint_fast32_t spill; REQUIRE(VALID_RESOLVER(res)); spill = atomic_load_acquire(&res->zspill); if (spill == 0) { return ISC_R_SUCCESS; } RWLOCK(&res->counters_lock, isc_rwlocktype_read); isc_hashmap_iter_create(res->counters, &it); for (result = isc_hashmap_iter_first(it); result == ISC_R_SUCCESS; result = isc_hashmap_iter_next(it)) { fctxcount_t *counter = NULL; uint_fast32_t count, dropped, allowed; char nb[DNS_NAME_FORMATSIZE]; char text[DNS_NAME_FORMATSIZE + BUFSIZ]; isc_hashmap_iter_current(it, (void **)&counter); LOCK(&counter->lock); count = counter->count; dropped = counter->dropped; allowed = counter->allowed; UNLOCK(&counter->lock); if (count < spill) { continue; } dns_name_format(counter->domain, nb, sizeof(nb)); snprintf(text, sizeof(text), "\n- %s: %" PRIuFAST32 " active (allowed %" PRIuFAST32 " spilled %" PRIuFAST32 ")", nb, count, allowed, dropped); result = isc_buffer_reserve(*buf, strlen(text)); if (result != ISC_R_SUCCESS) { goto cleanup; } isc_buffer_putstr(*buf, text); } if (result == ISC_R_NOMORE) { result = ISC_R_SUCCESS; } cleanup: RWUNLOCK(&res->counters_lock, isc_rwlocktype_read); isc_hashmap_iter_destroy(&it); return result; } void dns_resolver_setquotaresponse(dns_resolver_t *resolver, dns_quotatype_t which, isc_result_t resp) { REQUIRE(VALID_RESOLVER(resolver)); REQUIRE(which == dns_quotatype_zone || which == dns_quotatype_server); REQUIRE(resp == DNS_R_DROP || resp == DNS_R_SERVFAIL); resolver->quotaresp[which] = resp; } isc_result_t dns_resolver_getquotaresponse(dns_resolver_t *resolver, dns_quotatype_t which) { REQUIRE(VALID_RESOLVER(resolver)); REQUIRE(which == dns_quotatype_zone || which == dns_quotatype_server); return resolver->quotaresp[which]; } void dns_resolver_setstats(dns_resolver_t *res, isc_stats_t *stats) { REQUIRE(VALID_RESOLVER(res)); REQUIRE(res->stats == NULL); isc_stats_attach(stats, &res->stats); /* initialize the bucket "counter"; it's a static value */ set_stats(res, dns_resstatscounter_buckets, isc_loopmgr_nloops(res->loopmgr)); } void dns_resolver_getstats(dns_resolver_t *res, isc_stats_t **statsp) { REQUIRE(VALID_RESOLVER(res)); REQUIRE(statsp != NULL && *statsp == NULL); if (res->stats != NULL) { isc_stats_attach(res->stats, statsp); } } void dns_resolver_incstats(dns_resolver_t *res, isc_statscounter_t counter) { REQUIRE(VALID_RESOLVER(res)); isc_stats_increment(res->stats, counter); } void dns_resolver_setquerystats(dns_resolver_t *res, dns_stats_t *stats) { REQUIRE(VALID_RESOLVER(res)); REQUIRE(res->querystats == NULL); dns_stats_attach(stats, &res->querystats); } void dns_resolver_getquerystats(dns_resolver_t *res, dns_stats_t **statsp) { REQUIRE(VALID_RESOLVER(res)); REQUIRE(statsp != NULL && *statsp == NULL); if (res->querystats != NULL) { dns_stats_attach(res->querystats, statsp); } }