xfs: reject invalid flags combinations in XFS_IOC_ATTRLIST_BY_HANDLE

While the flags field in the ABI and the on-disk format allows for
multiple namespace flags, an attribute can only exist in a single
namespace at a time. Hence asking to list attributes that exist
in multiple namespaces simultaneously is a logically invalid
request and will return no results. Reject this case early with
-EINVAL.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Chandan Rajendra <chandanrlinux@gmail.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

fs/xfs/xfs_ioctl.c

@@ -317,6 +317,8 @@ xfs_attrlist_by_handle(
 	 */
 	if (al_hreq.flags & ~(ATTR_ROOT | ATTR_SECURE))
 		return -EINVAL;
+	if (al_hreq.flags == (ATTR_ROOT | ATTR_SECURE))
+		return -EINVAL;
 
 	dentry = xfs_handlereq_to_dentry(parfilp, &al_hreq.hreq);
 	if (IS_ERR(dentry))

fs/xfs/xfs_ioctl32.c

@@ -375,6 +375,8 @@ xfs_compat_attrlist_by_handle(
 	 */
 	if (al_hreq.flags & ~(ATTR_ROOT | ATTR_SECURE))
 		return -EINVAL;
+	if (al_hreq.flags == (ATTR_ROOT | ATTR_SECURE))
+		return -EINVAL;
 
 	dentry = xfs_compat_handlereq_to_dentry(parfilp, &al_hreq.hreq);
 	if (IS_ERR(dentry))