From 7fcbcdc96302e9d3e3b36df4fbc86a4c82761092 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Wed, 29 Aug 2012 16:25:49 +0000 Subject: netfilter: nf_conntrack: fix racy timer handling with reliable events 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 --- net/netfilter/nf_conntrack_core.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) (limited to 'net/netfilter/nf_conntrack_core.c') diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c index 729f157a0efa..9a171b2445b1 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -249,12 +249,15 @@ static void death_by_event(unsigned long ul_conntrack) { 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 */ @@ -268,6 +271,9 @@ static void death_by_event(unsigned long ul_conntrack) 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); @@ -275,10 +281,10 @@ void nf_ct_insert_dying_list(struct nf_conn *ct) &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); -- cgit v1.2.3