From afb7718016fcb0370ac29a83b2839c78b76c2960 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 27 Mar 2015 19:37:41 +0100 Subject: [PATCH] netfilter: x_tables: fix cgroup matching on non-full sks While originally only being intended for outgoing traffic, commit a00e76349f35 ("netfilter: x_tables: allow to use cgroup match for LOCAL_IN nf hooks") enabled xt_cgroups for the NF_INET_LOCAL_IN hook as well, in order to allow for nfacct accounting. Besides being currently limited to early demuxes only, commit a00e76349f35 forgot to add a check if we deal with full sockets, i.e. in this case not with time wait sockets. TCP time wait sockets do not have the same memory layout as full sockets, a lower memory footprint and consequently also don't have a sk_classid member; probing for sk_classid member there could potentially lead to a crash. Fixes: a00e76349f35 ("netfilter: x_tables: allow to use cgroup match for LOCAL_IN nf hooks") Cc: Alexey Perevalov Signed-off-by: Daniel Borkmann Signed-off-by: Pablo Neira Ayuso --- net/netfilter/xt_cgroup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/netfilter/xt_cgroup.c b/net/netfilter/xt_cgroup.c index 7198d660b4de..a1d126f29463 100644 --- a/net/netfilter/xt_cgroup.c +++ b/net/netfilter/xt_cgroup.c @@ -39,7 +39,7 @@ cgroup_mt(const struct sk_buff *skb, struct xt_action_param *par) { const struct xt_cgroup_info *info = par->matchinfo; - if (skb->sk == NULL) + if (skb->sk == NULL || !sk_fullsock(skb->sk)) return false; return (info->id == skb->sk->sk_classid) ^ info->invert; -- 2.20.1