From b240992a30c3d44e2261d0931b431f0112a553be Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Mon, 22 Jun 2009 14:14:41 +0200 Subject: [PATCH] netfilter: nf_conntrack: fix conntrack lookup race commit 8d8890b7751387f58ce0a6428773de2fbc0fd596 upstream. The RCU protected conntrack hash lookup only checks whether the entry has a refcount of zero to decide whether it is stale. This is not sufficient, entries are explicitly removed while there is at least one reference left, possibly more. Explicitly check whether the entry has been marked as dying to fix this. Signed-off-by: Patrick McHardy Signed-off-by: Greg Kroah-Hartman --- net/netfilter/nf_conntrack_core.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c index c8bd559bbf8..2d3584f0a75 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -295,7 +295,8 @@ begin: h = __nf_conntrack_find(net, tuple); if (h) { ct = nf_ct_tuplehash_to_ctrack(h); - if (unlikely(!atomic_inc_not_zero(&ct->ct_general.use))) + if (unlikely(nf_ct_is_dying(ct) || + !atomic_inc_not_zero(&ct->ct_general.use))) h = NULL; else { if (unlikely(!nf_ct_tuple_equal(tuple, &h->tuple))) { @@ -474,7 +475,8 @@ static noinline int early_drop(struct net *net, unsigned int hash) cnt++; } - if (ct && unlikely(!atomic_inc_not_zero(&ct->ct_general.use))) + if (ct && unlikely(nf_ct_is_dying(ct) || + !atomic_inc_not_zero(&ct->ct_general.use))) ct = NULL; if (ct || cnt >= NF_CT_EVICTION_RANGE) break; -- 2.11.4.GIT