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authorFlorian Westphal <fw@strlen.de>2013-04-11 04:22:39 +0000
committerPablo Neira Ayuso <pablo@netfilter.org>2013-04-12 11:46:31 +0200
commitc2d421e171868586939c328dfb91bab840fe4c49 (patch)
tree6452289ea13a425e5118d22f83a81bc86b6cb818 /net
parent6eb4c7e96e19fd2c38a103472048fc0e0e0a3ec3 (diff)
downloadvexpress-lsk-c2d421e171868586939c328dfb91bab840fe4c49.tar.gz
netfilter: nf_nat: fix race when unloading protocol modules
following oops was reported: RIP: 0010:[<ffffffffa03227f2>] [<ffffffffa03227f2>] nf_nat_cleanup_conntrack+0x42/0x70 [nf_nat] RSP: 0018:ffff880202c63d40 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff8801ac7bec28 RCX: ffff8801d0eedbe0 RDX: dead000000200200 RSI: 0000000000000011 RDI: ffffffffa03265b8 [..] Call Trace: [..] [<ffffffffa02febed>] destroy_conntrack+0xbd/0x110 [nf_conntrack] Happens when a conntrack timeout expires right after first part of the nat cleanup has completed (bysrc hash removal), but before part 2 has completed (re-initialization of nat area). [ destroy callback tries to delete bysrc again ] Patrick suggested to just remove the affected conntracks -- the connections won't work properly anyway without nat transformation. So, lets do that. Reported-by: CAI Qian <caiqian@redhat.com> Cc: Patrick McHardy <kaber@trash.net> Signed-off-by: Florian Westphal <fw@strlen.de> Acked-by: Patrick McHardy <kaber@trash.net> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net')
-rw-r--r--net/netfilter/nf_nat_core.c40
1 files changed, 7 insertions, 33 deletions
diff --git a/net/netfilter/nf_nat_core.c b/net/netfilter/nf_nat_core.c
index 8d5769c6d16..ad24be070e5 100644
--- a/net/netfilter/nf_nat_core.c
+++ b/net/netfilter/nf_nat_core.c
@@ -467,33 +467,22 @@ EXPORT_SYMBOL_GPL(nf_nat_packet);
struct nf_nat_proto_clean {
u8 l3proto;
u8 l4proto;
- bool hash;
};
-/* Clear NAT section of all conntracks, in case we're loaded again. */
-static int nf_nat_proto_clean(struct nf_conn *i, void *data)
+/* kill conntracks with affected NAT section */
+static int nf_nat_proto_remove(struct nf_conn *i, void *data)
{
const struct nf_nat_proto_clean *clean = data;
struct nf_conn_nat *nat = nfct_nat(i);
if (!nat)
return 0;
- if (!(i->status & IPS_SRC_NAT_DONE))
- return 0;
+
if ((clean->l3proto && nf_ct_l3num(i) != clean->l3proto) ||
(clean->l4proto && nf_ct_protonum(i) != clean->l4proto))
return 0;
- if (clean->hash) {
- spin_lock_bh(&nf_nat_lock);
- hlist_del_rcu(&nat->bysource);
- spin_unlock_bh(&nf_nat_lock);
- } else {
- memset(nat, 0, sizeof(*nat));
- i->status &= ~(IPS_NAT_MASK | IPS_NAT_DONE_MASK |
- IPS_SEQ_ADJUST);
- }
- return 0;
+ return i->status & IPS_NAT_MASK ? 1 : 0;
}
static void nf_nat_l4proto_clean(u8 l3proto, u8 l4proto)
@@ -505,16 +494,8 @@ static void nf_nat_l4proto_clean(u8 l3proto, u8 l4proto)
struct net *net;
rtnl_lock();
- /* Step 1 - remove from bysource hash */
- clean.hash = true;
for_each_net(net)
- nf_ct_iterate_cleanup(net, nf_nat_proto_clean, &clean);
- synchronize_rcu();
-
- /* Step 2 - clean NAT section */
- clean.hash = false;
- for_each_net(net)
- nf_ct_iterate_cleanup(net, nf_nat_proto_clean, &clean);
+ nf_ct_iterate_cleanup(net, nf_nat_proto_remove, &clean);
rtnl_unlock();
}
@@ -526,16 +507,9 @@ static void nf_nat_l3proto_clean(u8 l3proto)
struct net *net;
rtnl_lock();
- /* Step 1 - remove from bysource hash */
- clean.hash = true;
- for_each_net(net)
- nf_ct_iterate_cleanup(net, nf_nat_proto_clean, &clean);
- synchronize_rcu();
- /* Step 2 - clean NAT section */
- clean.hash = false;
for_each_net(net)
- nf_ct_iterate_cleanup(net, nf_nat_proto_clean, &clean);
+ nf_ct_iterate_cleanup(net, nf_nat_proto_remove, &clean);
rtnl_unlock();
}
@@ -773,7 +747,7 @@ static void __net_exit nf_nat_net_exit(struct net *net)
{
struct nf_nat_proto_clean clean = {};
- nf_ct_iterate_cleanup(net, &nf_nat_proto_clean, &clean);
+ nf_ct_iterate_cleanup(net, &nf_nat_proto_remove, &clean);
synchronize_rcu();
nf_ct_free_hashtable(net->ct.nat_bysource, net->ct.nat_htable_size);
}