From: Pablo Neira Ayuso <pablo@netfilter.org>
To: netfilter-devel@vger.kernel.org
Cc: fw@strlen.de, sven.auhagen@voleatech.de
Subject: [PATCH nf-next] netfilter: nf_conntrack_tcp: preserve liberal flag in tcp options
Date: Mon, 21 Mar 2022 10:42:05 +0100 [thread overview]
Message-ID: <20220321094205.63121-1-pablo@netfilter.org> (raw)
When tcp_options is called all flags are cleared.
When the IP_CT_TCP_FLAG_BE_LIBERAL is set it should be preserved
otherwise such connections will fail in the window check.
Signed-off-by: Sven Auhagen <sven.auhagen@voleatech.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
Supersedes: https://patchwork.ozlabs.org/project/netfilter-devel/patch/20220318144939.69465-1-pablo@netfilter.org/ which is not correct, it breaks TCP FIN handling.
net/netfilter/nf_conntrack_proto_tcp.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/net/netfilter/nf_conntrack_proto_tcp.c b/net/netfilter/nf_conntrack_proto_tcp.c
index d1582b888c0d..d8599ab5f767 100644
--- a/net/netfilter/nf_conntrack_proto_tcp.c
+++ b/net/netfilter/nf_conntrack_proto_tcp.c
@@ -342,7 +342,7 @@ static void tcp_options(const struct sk_buff *skb,
return;
state->td_scale =
- state->flags = 0;
+ state->flags &= IP_CT_TCP_FLAG_BE_LIBERAL;
while (length > 0) {
int opcode=*ptr++;
@@ -873,7 +873,7 @@ int nf_conntrack_tcp_packet(struct nf_conn *ct,
struct nf_tcp_net *tn = nf_tcp_pernet(net);
struct nf_conntrack_tuple *tuple;
enum tcp_conntrack new_state, old_state;
- unsigned int index, *timeouts;
+ unsigned int index, flags, *timeouts;
enum ip_conntrack_dir dir;
const struct tcphdr *th;
struct tcphdr _tcph;
@@ -968,8 +968,10 @@ int nf_conntrack_tcp_packet(struct nf_conn *ct,
ct->proto.tcp.last_flags &= ~IP_CT_EXP_CHALLENGE_ACK;
ct->proto.tcp.seen[ct->proto.tcp.last_dir].flags =
ct->proto.tcp.last_flags;
+ flags = ct->proto.tcp.seen[dir].flags;
memset(&ct->proto.tcp.seen[dir], 0,
sizeof(struct ip_ct_tcp_state));
+ ct->proto.tcp.seen[dir].flags = flags & IP_CT_TCP_FLAG_BE_LIBERAL;
break;
}
ct->proto.tcp.last_index = index;
--
2.30.2
next reply other threads:[~2022-03-21 9:42 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-21 9:42 Pablo Neira Ayuso [this message]
2022-03-21 9:44 ` [PATCH nf-next] netfilter: nf_conntrack_tcp: preserve liberal flag in tcp options Pablo Neira Ayuso
2022-03-21 9:46 ` Pablo Neira Ayuso
2022-03-21 10:05 ` Pablo Neira Ayuso
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