diff options
| author | Pablo Neira Ayuso <pablo@netfilter.org> | 2022-03-21 11:38:32 +0100 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2022-03-24 15:17:18 +0100 |
| commit | f2dd495a8d589371289981d5ed33e6873df94ecc (patch) | |
| tree | 5001723634f0f749b758c4f25ca7fb44672f5a19 | |
| parent | d645552e9bd96671079b27015294ec7f9748fa2b (diff) | |
| download | linux-f2dd495a8d589371289981d5ed33e6873df94ecc.tar.bz2 | |
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>
| -rw-r--r-- | net/netfilter/nf_conntrack_proto_tcp.c | 17 |
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; |