tree 3183e99bd38da761532685c045c2eac29c80b0b9
parent c095ba7224d8edc71dcef0d655911399a8bd4a3f
author Oleg Nesterov <oleg@redhat.com> 1375810735 +0200
committer Linus Torvalds <torvalds@linux-foundation.org> 1375820004 -0700

userns: unshare_userns(&cred) should not populate cred on failure

unshare_userns(new_cred) does *new_cred = prepare_creds() before
create_user_ns() which can fail. However, the caller expects that
it doesn't need to take care of new_cred if unshare_userns() fails.

We could change the single caller, sys_unshare(), but I think it
would be more clean to avoid the side effects on failure, so with
this patch unshare_userns() does put_cred() itself and initializes
*new_cred only if create_user_ns() succeeeds.

Cc: stable@vger.kernel.org
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>