[CVE-2011-4324] BUG statement in default case of encode_share_access

[Stefan Bader]

CVE-2011-4324:
  User can cause BUG on NFS4 mounted FS via mknod

Fix has hit Lucid and later via mainline. The upstream patch
for that is a bigger rewrite replacing access modes by the
fmode_t which was not present before 2.6.28.

Suggesting a minimal backport for Hardy.

---

>From af41fdc3d7c5d68ec75845d15f9ef4c77b31d110 Mon Sep 17 00:00:00 2001
From: Stefan Bader <stefan.bader at canonical.com>
Date: Fri, 10 Feb 2012 11:00:49 +0100
Subject: [hardy CVE] UBUNTU: SAUCE: Return deny all as default in
 encode_share_access

This used to be catched by BUG() which is not only unnecessary.
It was changed as part of a bigger rewrite that depends on a
typedef which does not exist before 2.6.28.

CVE-2011-4324
BugLink: http://bugs.launchpad.net/bugs/917829

(very loosely backported from dc0b027dfadfcb8a5504f7d8052754bf8d501ab9)
Signed-off-by: Stefan Bader <stefan.bader at canonical.com>
---
 fs/nfs/nfs4xdr.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 51dd380..cc66519 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -967,7 +967,7 @@ static void encode_share_access(struct xdr_stream *xdr, int open_flags)
 			WRITE32(NFS4_SHARE_ACCESS_BOTH);
 			break;
 		default:
-			BUG();
+			WRITE32(0);
 	}
 	WRITE32(0);		/* for linux, share_deny = 0 always */
 }
-- 
1.7.5.4