commit 1c91562def07c7186c2e17fc23efef75fb4dbd14
Author: Patrick McHardy <kaber@xxxxxxxxx>
Date: Fri Jul 3 10:33:45 2009 +0200
netfilter: nf_conntrack: fix conntrack lookup race
Upstream commit 8d8890b7:
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 <kaber@xxxxxxxxx>
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index c8bd559..2d3584f 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;
--
To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
