From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760237Ab3GZU6q (ORCPT ); Fri, 26 Jul 2013 16:58:46 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:51338 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760113Ab3GZU6U (ORCPT ); Fri, 26 Jul 2013 16:58:20 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Joe Jin , Eric Dumazet , "David S. Miller" Subject: [ 17/45] neighbour: fix a race in neigh_destroy() Date: Fri, 26 Jul 2013 13:57:37 -0700 Message-Id: <20130726205656.799260528@linuxfoundation.org> X-Mailer: git-send-email 1.8.3.rc0.20.gb99dd2e In-Reply-To: <20130726205654.896050165@linuxfoundation.org> References: <20130726205654.896050165@linuxfoundation.org> User-Agent: quilt/0.60-5.1.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit c9ab4d85de222f3390c67aedc9c18a50e767531e ] There is a race in neighbour code, because neigh_destroy() uses skb_queue_purge(&neigh->arp_queue) without holding neighbour lock, while other parts of the code assume neighbour rwlock is what protects arp_queue Convert all skb_queue_purge() calls to the __skb_queue_purge() variant Use __skb_queue_head_init() instead of skb_queue_head_init() to make clear we do not use arp_queue.lock And hold neigh->lock in neigh_destroy() to close the race. Reported-by: Joe Jin Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/core/neighbour.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -237,7 +237,7 @@ static void neigh_flush_dev(struct neigh we must kill timers etc. and move it to safe state. */ - skb_queue_purge(&n->arp_queue); + __skb_queue_purge(&n->arp_queue); n->output = neigh_blackhole; if (n->nud_state & NUD_VALID) n->nud_state = NUD_NOARP; @@ -291,7 +291,7 @@ static struct neighbour *neigh_alloc(str if (!n) goto out_entries; - skb_queue_head_init(&n->arp_queue); + __skb_queue_head_init(&n->arp_queue); rwlock_init(&n->lock); seqlock_init(&n->ha_lock); n->updated = n->used = now; @@ -712,7 +712,9 @@ void neigh_destroy(struct neighbour *nei hh_cache_put(hh); } - skb_queue_purge(&neigh->arp_queue); + write_lock_bh(&neigh->lock); + __skb_queue_purge(&neigh->arp_queue); + write_unlock_bh(&neigh->lock); dev_put(neigh->dev); neigh_parms_put(neigh->parms); @@ -864,7 +866,7 @@ static void neigh_invalidate(struct neig neigh->ops->error_report(neigh, skb); write_lock(&neigh->lock); } - skb_queue_purge(&neigh->arp_queue); + __skb_queue_purge(&neigh->arp_queue); } /* Called when a timer expires for a neighbour entry. */ @@ -1188,7 +1190,7 @@ int neigh_update(struct neighbour *neigh write_lock_bh(&neigh->lock); } - skb_queue_purge(&neigh->arp_queue); + __skb_queue_purge(&neigh->arp_queue); } out: if (update_isrouter) {