From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758053Ab2JSDRj (ORCPT ); Thu, 18 Oct 2012 23:17:39 -0400 Received: from mail.kernel.org ([198.145.19.201]:54550 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964973Ab2JSDRd (ORCPT ); Thu, 18 Oct 2012 23:17:33 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , alan@lxorguk.ukuu.org.uk, Oliver Smith , Pablo Neira Ayuso , David Miller Subject: [ 21/37] netfilter: nf_conntrack: fix racy timer handling with reliable events Date: Thu, 18 Oct 2012 20:16:44 -0700 Message-Id: <20121019031306.259370460@linuxfoundation.org> X-Mailer: git-send-email 1.8.0.rc0.18.gf84667d In-Reply-To: <20121019031302.789593147@linuxfoundation.org> References: <20121019031302.789593147@linuxfoundation.org> User-Agent: quilt/0.60-2.1.2 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: Pablo Neira Ayuso commit 5b423f6a40a0327f9d40bc8b97ce9be266f74368 upstream. Existing code assumes that del_timer returns true for alive conntrack entries. However, this is not true if reliable events are enabled. In that case, del_timer may return true for entries that were just inserted in the dying list. Note that packets / ctnetlink may hold references to conntrack entries that were just inserted to such list. This patch fixes the issue by adding an independent timer for event delivery. This increases the size of the ecache extension. Still we can revisit this later and use variable size extensions to allocate this area on demand. Tested-by: Oliver Smith Signed-off-by: Pablo Neira Ayuso Acked-by: David Miller Signed-off-by: Greg Kroah-Hartman --- include/net/netfilter/nf_conntrack_ecache.h | 1 + net/netfilter/nf_conntrack_core.c | 16 +++++++++++----- 2 files changed, 12 insertions(+), 5 deletions(-) --- a/include/net/netfilter/nf_conntrack_ecache.h +++ b/include/net/netfilter/nf_conntrack_ecache.h @@ -18,6 +18,7 @@ struct nf_conntrack_ecache { u16 ctmask; /* bitmask of ct events to be delivered */ u16 expmask; /* bitmask of expect events to be delivered */ u32 pid; /* netlink pid of destroyer */ + struct timer_list timeout; }; static inline struct nf_conntrack_ecache * --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -247,12 +247,15 @@ static void death_by_event(unsigned long { struct nf_conn *ct = (void *)ul_conntrack; struct net *net = nf_ct_net(ct); + struct nf_conntrack_ecache *ecache = nf_ct_ecache_find(ct); + + BUG_ON(ecache == NULL); if (nf_conntrack_event(IPCT_DESTROY, ct) < 0) { /* bad luck, let's retry again */ - ct->timeout.expires = jiffies + + ecache->timeout.expires = jiffies + (random32() % net->ct.sysctl_events_retry_timeout); - add_timer(&ct->timeout); + add_timer(&ecache->timeout); return; } /* we've got the event delivered, now it's dying */ @@ -266,6 +269,9 @@ static void death_by_event(unsigned long void nf_ct_insert_dying_list(struct nf_conn *ct) { struct net *net = nf_ct_net(ct); + struct nf_conntrack_ecache *ecache = nf_ct_ecache_find(ct); + + BUG_ON(ecache == NULL); /* add this conntrack to the dying list */ spin_lock_bh(&nf_conntrack_lock); @@ -273,10 +279,10 @@ void nf_ct_insert_dying_list(struct nf_c &net->ct.dying); spin_unlock_bh(&nf_conntrack_lock); /* set a new timer to retry event delivery */ - setup_timer(&ct->timeout, death_by_event, (unsigned long)ct); - ct->timeout.expires = jiffies + + setup_timer(&ecache->timeout, death_by_event, (unsigned long)ct); + ecache->timeout.expires = jiffies + (random32() % net->ct.sysctl_events_retry_timeout); - add_timer(&ct->timeout); + add_timer(&ecache->timeout); } EXPORT_SYMBOL_GPL(nf_ct_insert_dying_list);