From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: [PATCH] posix_acl: handle NULL ACL in posix_acl_equiv_mode Date: Sun, 4 May 2014 13:03:32 +0200 Message-ID: <1399201412-17938-1-git-send-email-hch@lst.de> Cc: linux-fsdevel@vger.kernel.org, Chuck Lever , stable@vger.kernel.org To: Al Viro Return-path: Received: from casper.infradead.org ([85.118.1.10]:51352 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753628AbaEDLBR (ORCPT ); Sun, 4 May 2014 07:01:17 -0400 Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Various filesystems don't bother checking for a NULL ACL in posix_acl_equiv_mode, and thus can dereference a NULL pointer when it gets passed one. This usually happens from the NFS server, as the ACL tools never pass a NULL ACL, but instead of one representing the mode bits. Instead of adding boilerplat to all filesystems put this check into one place, which will allow us to remove the check from other filesystems as well later on. Signed-off-by: Christoph Hellwig Reported-by: Ben Greear Reported-by: Marco Munderloh , Cc: Chuck Lever Cc: stable@vger.kernel.org --- fs/posix_acl.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/posix_acl.c b/fs/posix_acl.c index 9e363e4..0855f77 100644 --- a/fs/posix_acl.c +++ b/fs/posix_acl.c @@ -246,6 +246,12 @@ posix_acl_equiv_mode(const struct posix_acl *acl, umode_t *mode_p) umode_t mode = 0; int not_equiv = 0; + /* + * A null ACL can always be presented as mode bits. + */ + if (!acl) + return 0; + FOREACH_ACL_ENTRY(pa, acl, pe) { switch (pa->e_tag) { case ACL_USER_OBJ: -- 1.7.10.4