diff options
| author | Pablo Neira Ayuso <pablo@netfilter.org> | 2022-03-21 11:38:32 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-04-08 14:40:28 +0200 |
| commit | 8cd30d28da01e6c29fabca1494baba4f11191ac1 (patch) | |
| tree | a0315dabeb4d41c53890707732083173284458fa /net/netfilter | |
| parent | fbd56a61ceee221feea7fc978404e8d458e948a2 (diff) | |
netfilter: nf_conntrack_tcp: preserve liberal flag in tcp options
[ Upstream commit f2dd495a8d589371289981d5ed33e6873df94ecc ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'net/netfilter')
| -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 c8fb2187ad4b..3f785bdfa942 100644 --- a/net/netfilter/nf_conntrack_proto_tcp.c +++ b/net/netfilter/nf_conntrack_proto_tcp.c @@ -354,8 +354,8 @@ static void tcp_options(const struct sk_buff *skb, length, buff); BUG_ON(ptr == NULL); - state->td_scale = - state->flags = 0; + state->td_scale = 0; + state->flags &= IP_CT_TCP_FLAG_BE_LIBERAL; while (length > 0) { int opcode=*ptr++; @@ -840,6 +840,16 @@ static bool nf_conntrack_tcp_established(const struct nf_conn *ct) test_bit(IPS_ASSURED_BIT, &ct->status); } +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, @@ -946,8 +956,7 @@ 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; |