netfilter: fix nf_conntrack_l4proto_register()

While doing __rcu annotations work on net/netfilter I found following
bug. On some arches, it is possible we publish a table while its content
is not yet committed to memory, and lockless reader can dereference wild
pointer.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
This commit is contained in:
Eric Dumazet 2010-10-29 19:59:40 +02:00 committed by Patrick McHardy
parent 64e4674922
commit d817d29d0b

View File

@ -292,6 +292,12 @@ int nf_conntrack_l4proto_register(struct nf_conntrack_l4proto *l4proto)
for (i = 0; i < MAX_NF_CT_PROTO; i++) for (i = 0; i < MAX_NF_CT_PROTO; i++)
proto_array[i] = &nf_conntrack_l4proto_generic; proto_array[i] = &nf_conntrack_l4proto_generic;
/* Before making proto_array visible to lockless readers,
* we must make sure its content is committed to memory.
*/
smp_wmb();
nf_ct_protos[l4proto->l3proto] = proto_array; nf_ct_protos[l4proto->l3proto] = proto_array;
} else if (nf_ct_protos[l4proto->l3proto][l4proto->l4proto] != } else if (nf_ct_protos[l4proto->l3proto][l4proto->l4proto] !=
&nf_conntrack_l4proto_generic) { &nf_conntrack_l4proto_generic) {