summaryrefslogtreecommitdiff
path: root/net
diff options
context:
space:
mode:
authorPablo Neira Ayuso <pablo@netfilter.org>2022-03-21 13:38:32 +0300
committerPablo Neira Ayuso <pablo@netfilter.org>2022-03-24 17:17:18 +0300
commitf2dd495a8d589371289981d5ed33e6873df94ecc (patch)
tree5001723634f0f749b758c4f25ca7fb44672f5a19 /net
parentd645552e9bd96671079b27015294ec7f9748fa2b (diff)
downloadlinux-f2dd495a8d589371289981d5ed33e6873df94ecc.tar.xz
netfilter: nf_conntrack_tcp: preserve liberal flag in tcp options
Do not reset IP_CT_TCP_FLAG_BE_LIBERAL flag in out-of-sync scenarios coming before the TCP window tracking, otherwise such connections will fail in the window check. Update tcp_options() to leave this flag in place and add a new helper function to reset the tcp window state. Based on patch from Sven Auhagen. Fixes: c4832c7bbc3f ("netfilter: nf_ct_tcp: improve out-of-sync situation in TCP tracking") Tested-by: Sven Auhagen <sven.auhagen@voleatech.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net')
-rw-r--r--net/netfilter/nf_conntrack_proto_tcp.c17
1 files changed, 13 insertions, 4 deletions
diff --git a/net/netfilter/nf_conntrack_proto_tcp.c b/net/netfilter/nf_conntrack_proto_tcp.c
index d1582b888c0d..8ec55cd72572 100644
--- a/net/netfilter/nf_conntrack_proto_tcp.c
+++ b/net/netfilter/nf_conntrack_proto_tcp.c
@@ -341,8 +341,8 @@ static void tcp_options(const struct sk_buff *skb,
if (!ptr)
return;
- state->td_scale =
- state->flags = 0;
+ state->td_scale = 0;
+ state->flags &= IP_CT_TCP_FLAG_BE_LIBERAL;
while (length > 0) {
int opcode=*ptr++;
@@ -862,6 +862,16 @@ static bool tcp_can_early_drop(const struct nf_conn *ct)
return false;
}
+static void nf_ct_tcp_state_reset(struct ip_ct_tcp_state *state)
+{
+ state->td_end = 0;
+ state->td_maxend = 0;
+ state->td_maxwin = 0;
+ state->td_maxack = 0;
+ state->td_scale = 0;
+ state->flags &= IP_CT_TCP_FLAG_BE_LIBERAL;
+}
+
/* Returns verdict for packet, or -1 for invalid. */
int nf_conntrack_tcp_packet(struct nf_conn *ct,
struct sk_buff *skb,
@@ -968,8 +978,7 @@ 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;
- memset(&ct->proto.tcp.seen[dir], 0,
- sizeof(struct ip_ct_tcp_state));
+ nf_ct_tcp_state_reset(&ct->proto.tcp.seen[dir]);
break;
}
ct->proto.tcp.last_index = index;