From: Steven Whitehouse <swhiteho@redhat.com>
Date: Wed, 10 Mar 2010 15:56:10 -0500
Subject: [fs] gfs2: locking fix for potential dos
Message-id: <1268236570.8777.11.camel@localhost>
Patchwork-id: 23536
O-Subject: [RHEL 5.5] GFS2: Mandatory locking fix (bz #570863/#571298) -
	EMBARGOED
Bugzilla: 572390
CVE: CVE-2010-0727

Here is the very simple fix for this bz. This is the RHEL5 version of
the fix for which I posted the RHEL6 version earlier. This fixes bz
#572390.

Signed-off-by: Jarod Wilson <jarod@redhat.com>

diff --git a/fs/gfs2/ops_file.c b/fs/gfs2/ops_file.c
index 3b8d44e..2e684bf 100644
--- a/fs/gfs2/ops_file.c
+++ b/fs/gfs2/ops_file.c
@@ -694,7 +694,8 @@ static int gfs2_lock(struct file *file, int cmd, struct file_lock *fl)
 
 	if (!(fl->fl_flags & FL_POSIX))
 		return -ENOLCK;
-	if ((ip->i_inode.i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
+	if ((ip->i_inode.i_mode & (S_ISGID | S_IXGRP)) == S_ISGID &&
+		fl->fl_type != F_UNLCK)
 		return -ENOLCK;
 
 	if (sdp->sd_args.ar_localflocks) {