ocfs2: trusted xattr missing CAP_SYS_ADMIN check

The trusted extended attributes are only visible to the process which
hvae CAP_SYS_ADMIN capability but the check is missing in ocfs2
xattr_handler trusted list.  The check is important because this will be
used for implementing mechanisms in the userspace for which other
ordinary processes should not have access to.

Signed-off-by: Sanidhya Kashyap <sanidhya.gatech@gmail.com>
Reviewed-by: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Taesoo kim <taesoo@gatech.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit 0f5e7b41f91814447defc34e915fc5d6e52266d9)

Orabug: 24939243

Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com>

diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
index d03bfbf3d27d503b3b10bc912f30da9d494c1edb..d5a4050519173239b8c812bd9ee9b518bbf32161 100644 (file)
--- a/fs/ocfs2/xattr.c
+++ b/fs/ocfs2/xattr.c
@@ -7334,6 +7334,9 @@ static size_t ocfs2_xattr_trusted_list(struct dentry *dentry, char *list,
        const size_t prefix_len = XATTR_TRUSTED_PREFIX_LEN;
        const size_t total_len = prefix_len + name_len + 1;
 
+       if (!capable(CAP_SYS_ADMIN))
+               return 0;
+
        if (list && total_len <= list_size) {
                memcpy(list, XATTR_TRUSTED_PREFIX, prefix_len);
                memcpy(list + prefix_len, name, name_len);