From cae3eae929f04b83dc1eb4cf04736b2ce32843ee Mon Sep 17 00:00:00 2001 From: David Leadbeater Date: Tue, 18 Oct 2022 21:41:00 +0200 Subject: [PATCH] netfilter: nf_conntrack_irc: Fix forged IP logic Ensure the match happens in the right direction, previously the destination used was the server, not the NAT host, as the comment shows the code intended. Additionally nf_nat_irc uses port 0 as a signal and there's no valid way it can appear in a DCC message, so consider port 0 also forged. Fixes: 869f37d8e48f ("[NETFILTER]: nf_conntrack/nf_nat: add IRC helper port") Signed-off-by: David Leadbeater Signed-off-by: Pablo Neira Ayuso CVE-2022-2663 (cherry picked from commit 0efe125cfb99e6773a7434f3463f7c2fa28f3a43) Signed-off-by: John Cabaj Acked-by: Thadeu Lima de Souza Cascardo Acked-by: Luke Nowakowski-Krijger Signed-off-by: Stefan Bader --- net/netfilter/nf_conntrack_irc.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/net/netfilter/nf_conntrack_irc.c b/net/netfilter/nf_conntrack_irc.c index 08ee4e760a3d..18b90e334b5b 100644 --- a/net/netfilter/nf_conntrack_irc.c +++ b/net/netfilter/nf_conntrack_irc.c @@ -188,8 +188,9 @@ static int help(struct sk_buff *skb, unsigned int protoff, /* dcc_ip can be the internal OR external (NAT'ed) IP */ tuple = &ct->tuplehash[dir].tuple; - if (tuple->src.u3.ip != dcc_ip && - tuple->dst.u3.ip != dcc_ip) { + if ((tuple->src.u3.ip != dcc_ip && + ct->tuplehash[!dir].tuple.dst.u3.ip != dcc_ip) || + dcc_port == 0) { net_warn_ratelimited("Forged DCC command from %pI4: %pI4:%u\n", &tuple->src.u3.ip, &dcc_ip, dcc_port); -- 2.39.2