From 0efe125cfb99e6773a7434f3463f7c2fa28f3a43 Mon Sep 17 00:00:00 2001 From: David Leadbeater Date: Fri, 26 Aug 2022 14:56:58 +1000 Subject: 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 --- net/netfilter/nf_conntrack_irc.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'net/netfilter/nf_conntrack_irc.c') diff --git a/net/netfilter/nf_conntrack_irc.c b/net/netfilter/nf_conntrack_irc.c index 1796c456ac98..992decbcaa5c 100644 --- a/net/netfilter/nf_conntrack_irc.c +++ b/net/netfilter/nf_conntrack_irc.c @@ -194,8 +194,9 @@ 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); -- cgit