reiserfs: add atomic addition of selinux attributes during inode creation

Some time ago, some changes were made to make security inode attributes
be atomically written during inode creation.  ReiserFS fell behind in
this area, but with the reworking of the xattr code, it's now fairly
easy to add.

The following patch adds the ability for security attributes to be added
automatically during inode creation.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 54 insertions, 0 deletions

diff --git a/fs/reiserfs/xattr_security.c b/fs/reiserfs/xattr_security.c
index 2aacf1fe69fd..4d3c20e787c3 100644
--- a/fs/reiserfs/xattr_security.c
+++ b/fs/reiserfs/xattr_security.c
@@ -4,6 +4,7 @@
 #include <linux/pagemap.h>
 #include <linux/xattr.h>
 #include <linux/reiserfs_xattr.h>
+#include <linux/security.h>
 #include <asm/uaccess.h>
 
 static int
@@ -47,6 +48,59 @@ static size_t security_list(struct inode *inode, char *list, size_t list_len,
         return len;
 }
 
+/* Initializes the security context for a new inode and returns the number
+ * of blocks needed for the transaction. If successful, reiserfs_security
+ * must be released using reiserfs_security_free when the caller is done. */
+int reiserfs_security_init(struct inode *dir, struct inode *inode,
+                           struct reiserfs_security_handle *sec)
+{
+        int blocks = 0;
+        int error = security_inode_init_security(inode, dir, &sec->name,
+                                                 &sec->value, &sec->length);
+        if (error) {
+                if (error == -EOPNOTSUPP)
+                        error = 0;
+
+                sec->name = NULL;
+                sec->value = NULL;
+                sec->length = 0;
+                return error;
+        }
+
+        if (sec->length) {
+                blocks = reiserfs_xattr_jcreate_nblocks(inode) +
+                         reiserfs_xattr_nblocks(inode, sec->length);
+                /* We don't want to count the directories twice if we have
+                 * a default ACL. */
+                REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
+        }
+        return blocks;
+}
+
+int reiserfs_security_write(struct reiserfs_transaction_handle *th,
+                            struct inode *inode,
+                            struct reiserfs_security_handle *sec)
+{
+        int error;
+        if (strlen(sec->name) < sizeof(XATTR_SECURITY_PREFIX))
+                return -EINVAL;
+
+        error = reiserfs_xattr_set_handle(th, inode, sec->name, sec->value,
+                                          sec->length, XATTR_CREATE);
+        if (error == -ENODATA || error == -EOPNOTSUPP)
+                error = 0;
+
+        return error;
+}
+
+void reiserfs_security_free(struct reiserfs_security_handle *sec)
+{
+        kfree(sec->name);
+        kfree(sec->value);
+        sec->name = NULL;
+        sec->value = NULL;
+}
+
 struct xattr_handler reiserfs_xattr_security_handler = {
         .prefix = XATTR_SECURITY_PREFIX,
         .get = security_get,