From patchwork Fri Nov 14 16:58:49 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pablo Neira Ayuso X-Patchwork-Id: 410929 X-Patchwork-Delegate: pablo@netfilter.org Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 5E86E140082 for ; Sat, 15 Nov 2014 03:57:38 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161414AbaKNQ5g (ORCPT ); Fri, 14 Nov 2014 11:57:36 -0500 Received: from mail.us.es ([193.147.175.20]:40397 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161394AbaKNQ5W (ORCPT ); Fri, 14 Nov 2014 11:57:22 -0500 Received: (qmail 28113 invoked from network); 14 Nov 2014 17:57:20 +0100 Received: from unknown (HELO us.es) (192.168.2.16) by us.es with SMTP; 14 Nov 2014 17:57:20 +0100 Received: (qmail 7141 invoked by uid 507); 14 Nov 2014 16:57:20 -0000 X-Qmail-Scanner-Diagnostics: from 127.0.0.1 by antivirus6 (envelope-from , uid 501) with qmail-scanner-2.10 (clamdscan: 0.98.4/19628. spamassassin: 3.3.2. Clear:RC:1(127.0.0.1):SA:0(-103.2/7.5):. Processed in 1.880444 secs); 14 Nov 2014 16:57:20 -0000 X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on antivirus6 X-Spam-Level: X-Spam-Status: No, score=-103.2 required=7.5 tests=BAYES_50,SMTPAUTH_US, USER_IN_WHITELIST autolearn=disabled version=3.3.2 X-Spam-ASN: AS12715 87.216.0.0/16 X-Envelope-From: pablo@netfilter.org Received: from unknown (HELO antivirus6) (127.0.0.1) by us.es with SMTP; 14 Nov 2014 16:57:18 -0000 Received: from 192.168.1.13 (192.168.1.13) by antivirus6 (F-Secure/fsigk_smtp/412/antivirus6); Fri, 14 Nov 2014 17:57:18 +0100 (CET) X-Virus-Status: clean(F-Secure/fsigk_smtp/412/antivirus6) Received: (qmail 9476 invoked from network); 14 Nov 2014 17:57:18 +0100 Received: from 129.166.216.87.static.jazztel.es (HELO salvia.here) (pneira@us.es@87.216.166.129) by mail.us.es with SMTP; 14 Nov 2014 17:57:18 +0100 From: Pablo Neira Ayuso To: netfilter-devel@vger.kernel.org Cc: davem@davemloft.net, netdev@vger.kernel.org Subject: [PATCH 8/8] netfilter: conntrack: fix race in __nf_conntrack_confirm against get_next_corpse Date: Fri, 14 Nov 2014 17:58:49 +0100 Message-Id: <1415984329-5569-10-git-send-email-pablo@netfilter.org> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1415984329-5569-1-git-send-email-pablo@netfilter.org> References: <1415984329-5569-1-git-send-email-pablo@netfilter.org> Sender: netfilter-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org From: bill bonaparte After removal of the central spinlock nf_conntrack_lock, in commit 93bb0ceb75be2 ("netfilter: conntrack: remove central spinlock nf_conntrack_lock"), it is possible to race against get_next_corpse(). The race is against the get_next_corpse() cleanup on the "unconfirmed" list (a per-cpu list with seperate locking), which set the DYING bit. Fix this race, in __nf_conntrack_confirm(), by removing the CT from unconfirmed list before checking the DYING bit. In case race occured, re-add the CT to the dying list. While at this, fix coding style of the comment that has been updated. Fixes: 93bb0ceb75be2 ("netfilter: conntrack: remove central spinlock nf_conntrack_lock") Reported-by: bill bonaparte Signed-off-by: bill bonaparte Signed-off-by: Jesper Dangaard Brouer Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_conntrack_core.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c index 5016a69..2c69975 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -611,12 +611,16 @@ __nf_conntrack_confirm(struct sk_buff *skb) */ NF_CT_ASSERT(!nf_ct_is_confirmed(ct)); pr_debug("Confirming conntrack %p\n", ct); - /* We have to check the DYING flag inside the lock to prevent - a race against nf_ct_get_next_corpse() possibly called from - user context, else we insert an already 'dead' hash, blocking - further use of that particular connection -JM */ + + /* We have to check the DYING flag after unlink to prevent + * a race against nf_ct_get_next_corpse() possibly called from + * user context, else we insert an already 'dead' hash, blocking + * further use of that particular connection -JM. + */ + nf_ct_del_from_dying_or_unconfirmed_list(ct); if (unlikely(nf_ct_is_dying(ct))) { + nf_ct_add_to_dying_list(ct); nf_conntrack_double_unlock(hash, reply_hash); local_bh_enable(); return NF_ACCEPT; @@ -636,8 +640,6 @@ __nf_conntrack_confirm(struct sk_buff *skb) zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h))) goto out; - nf_ct_del_from_dying_or_unconfirmed_list(ct); - /* Timer relative to confirmation time, not original setting time, otherwise we'd get timer wrap in weird delay cases. */