From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932072Ab2L1Trm (ORCPT ); Fri, 28 Dec 2012 14:47:42 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:55172 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754656Ab2L1TSB (ORCPT ); Fri, 28 Dec 2012 14:18:01 -0500 Message-Id: <20121228190356.817518151@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Fri, 28 Dec 2012 20:05:38 +0100 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, NeilBrown , Trond Myklebust Subject: [ 128/173] NFS: avoid NULL dereference in nfs_destroy_server In-Reply-To: <20121228190330.025298996@decadent.org.uk> X-SA-Exim-Connect-IP: 151.217.219.220 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: NeilBrown commit f259613a1e4b44a0cf85a5dafd931be96ee7c9e5 upstream. In rare circumstances, nfs_clone_server() of a v2 or v3 server can get an error between setting server->destory (to nfs_destroy_server), and calling nfs_start_lockd (which will set server->nlm_host). If this happens, nfs_clone_server will call nfs_free_server which will call nfs_destroy_server and thence nlmclnt_done(NULL). This causes the NULL to be dereferenced. So add a guard to only call nlmclnt_done() if ->nlm_host is not NULL. The other guards there are irrelevant as nlm_host can only be non-NULL if one of these flags are set - so remove those tests. (Thanks to Trond for this suggestion). This is suitable for any stable kernel since 2.6.25. Signed-off-by: NeilBrown Signed-off-by: Trond Myklebust Signed-off-by: Ben Hutchings --- fs/nfs/client.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/fs/nfs/client.c b/fs/nfs/client.c index c285e0a..9f3c664 100644 --- a/fs/nfs/client.c +++ b/fs/nfs/client.c @@ -615,8 +615,7 @@ EXPORT_SYMBOL_GPL(nfs_create_rpc_client); */ static void nfs_destroy_server(struct nfs_server *server) { - if (!(server->flags & NFS_MOUNT_LOCAL_FLOCK) || - !(server->flags & NFS_MOUNT_LOCAL_FCNTL)) + if (server->nlm_host) nlmclnt_done(server->nlm_host); }