Description of problem: Frank Filz reported: the problem is that permission checking is skipped if atomic open is possible, but when exec opens a file, it just opens it OREADONLY which means EXEC permission will not be checked at that time.

This problem is observed by the following sequence (executed as root):

mount -t nfs4 server:/ /mnt4 echo "ls" >/mnt4/foo chmod 744 /mnt4/foo su guest -c "mnt4/foo"

Reference: http://article.gmane.org/gmane.linux.nfs/26592