Btrfs: should add a permission check for setfacl

commit 2f26afba46f0ebf155cf9be746496a0304a5b7cf upstream.

On btrfs, do the following
------------------
# su user1
# cd btrfs-part/
# touch aaa
# getfacl aaa
  # file: aaa
  # owner: user1
  # group: user1
  user::rw-
  group::rw-
  other::r--
# su user2
# cd btrfs-part/
# setfacl -m u::rwx aaa
# getfacl aaa
  # file: aaa
  # owner: user1
  # group: user1
  user::rwx           <- successed to setfacl
  group::rw-
  other::r--
------------------
but we should prohibit it that user2 changing user1's acl.
In fact, on ext3 and other fs, a message occurs:
  setfacl: aaa: Operation not permitted

This patch fixed it.

Signed-off-by: Shi Weihua <shiwh@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/fs/btrfs/acl.c b/fs/btrfs/acl.c
index 36160424427124947179e7270bfb77e03dbc1686..38ebe789b5628e9ddb6a5076b523612b5b988476 100644 (file)
--- a/fs/btrfs/acl.c
+++ b/fs/btrfs/acl.c
@@ -157,6 +157,9 @@ static int btrfs_xattr_set_acl(struct inode *inode, int type,
        int ret = 0;
        struct posix_acl *acl = NULL;
 
+       if (!is_owner_or_cap(inode))
+               return -EPERM;
+
        if (value) {
                acl = posix_acl_from_xattr(value, size);
                if (acl == NULL) {