From: Jeffrey Mahoney <jeffm@novell.com>
ReiserFS implements extended attributes by backing them with regular files.
This means that selinux would create an infinite series of
xattrs-on-xattrs-on-xattrs etc. However, due to the locking of xattrs, this
series never happens. Instead, a locking loop occurs.
This patch allows SElinux to mark inodes as "private," such that SElinux
attributes aren't associated with them.
Original implementation by Stephen Smalley <sds@epoch.ncsc.mil>
Signed-off-by: Jeff Mahoney <jeffm@novell.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/include/linux/security.h | 14 ++++++++++++++
25-akpm/security/dummy.c | 6 ++++++
25-akpm/security/selinux/hooks.c | 19 +++++++++++++++++++
3 files changed, 39 insertions(+)
diff -puN include/linux/security.h~selinux-adds-a-private-inode-operation include/linux/security.h
--- 25/include/linux/security.h~selinux-adds-a-private-inode-operation 2004-12-03 20:57:08.235386832 -0800
+++ 25-akpm/include/linux/security.h 2004-12-03 20:57:08.243385616 -0800
@@ -409,6 +409,11 @@ struct swap_info_struct;
* is specified by @buffer_size. @buffer may be NULL to request
* the size of the buffer required.
* Returns number of bytes used/required on success.
+ * @inode_mark_private:
+ * Set up the security state of @inode to reflect the fact that the inode
+ * is private, i.e. used internally by the filesystem for purposes such
+ * as xattr storage and not accessible by userspace. This property should
+ * then be inherited by all nodes under this node.
*
* Security hooks for file operations
*
@@ -1114,6 +1119,7 @@ struct security_operations {
int (*inode_getsecurity)(struct inode *inode, const char *name, void *buffer, size_t size);
int (*inode_setsecurity)(struct inode *inode, const char *name, const void *value, size_t size, int flags);
int (*inode_listsecurity)(struct inode *inode, char *buffer, size_t buffer_size);
+ void (*inode_mark_private)(struct inode *inode);
int (*file_permission) (struct file * file, int mask);
int (*file_alloc_security) (struct file * file);
@@ -1598,6 +1604,11 @@ static inline int security_inode_listsec
return security_ops->inode_listsecurity(inode, buffer, buffer_size);
}
+static inline void security_inode_mark_private(struct inode *inode)
+{
+ security_ops->inode_mark_private(inode);
+}
+
static inline int security_file_permission (struct file *file, int mask)
{
return security_ops->file_permission (file, mask);
@@ -2242,6 +2253,9 @@ static inline int security_inode_listsec
return 0;
}
+static inline void security_inode_mark_private(struct inode *inode)
+{ }
+
static inline int security_file_permission (struct file *file, int mask)
{
return 0;
diff -puN security/dummy.c~selinux-adds-a-private-inode-operation security/dummy.c
--- 25/security/dummy.c~selinux-adds-a-private-inode-operation 2004-12-03 20:57:08.237386528 -0800
+++ 25-akpm/security/dummy.c 2004-12-03 20:57:08.244385464 -0800
@@ -477,6 +477,11 @@ static int dummy_inode_listsecurity(stru
return 0;
}
+static void dummy_inode_mark_private(struct inode *inode)
+{
+ return;
+}
+
static int dummy_file_permission (struct file *file, int mask)
{
return 0;
@@ -964,6 +969,7 @@ void security_fixup_ops (struct security
set_to_dummy_if_null(ops, inode_getsecurity);
set_to_dummy_if_null(ops, inode_setsecurity);
set_to_dummy_if_null(ops, inode_listsecurity);
+ set_to_dummy_if_null(ops, inode_mark_private);
set_to_dummy_if_null(ops, file_permission);
set_to_dummy_if_null(ops, file_alloc_security);
set_to_dummy_if_null(ops, file_free_security);
diff -puN security/selinux/hooks.c~selinux-adds-a-private-inode-operation security/selinux/hooks.c
--- 25/security/selinux/hooks.c~selinux-adds-a-private-inode-operation 2004-12-03 20:57:08.238386376 -0800
+++ 25-akpm/security/selinux/hooks.c 2004-12-03 20:57:08.248384856 -0800
@@ -737,6 +737,15 @@ static int inode_doinit_with_dentry(stru
if (isec->initialized)
goto out;
+ if (opt_dentry && opt_dentry->d_parent && opt_dentry->d_parent->d_inode) {
+ struct inode_security_struct *pisec = opt_dentry->d_parent->d_inode->i_security;
+ if (pisec->inherit) {
+ isec->sid = pisec->sid;
+ isec->initialized = 1;
+ goto out;
+ }
+ }
+
down(&isec->sem);
hold_sem = 1;
if (isec->initialized)
@@ -2366,6 +2375,15 @@ static int selinux_inode_listsecurity(st
return len;
}
+static void selinux_inode_mark_private(struct inode *inode)
+{
+ struct inode_security_struct *isec = inode->i_security;
+
+ isec->sid = SECINITSID_KERNEL;
+ isec->initialized = 1;
+ isec->inherit = 1;
+}
+
/* file security operations */
static int selinux_file_permission(struct file *file, int mask)
@@ -4259,6 +4277,7 @@ struct security_operations selinux_ops =
.inode_getsecurity = selinux_inode_getsecurity,
.inode_setsecurity = selinux_inode_setsecurity,
.inode_listsecurity = selinux_inode_listsecurity,
+ .inode_mark_private = selinux_inode_mark_private,
.file_permission = selinux_file_permission,
.file_alloc_security = selinux_file_alloc_security,
_