diff options
| author | Marcelo Leitner <mleitner@redhat.com> | 2014-10-13 13:09:28 -0300 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2014-10-22 14:12:50 +0200 |
| commit | e37ad9fd636071e45368d1d9cc3b7b421281ce7f (patch) | |
| tree | e44d86031de19e16ee5632d866178c82ce0d5ced /net | |
| parent | 7c1c97d54f9bfc810908d3903cb8bcacf734df18 (diff) | |
netfilter: nf_conntrack: allow server to become a client in TW handling
When a port that was used to listen for inbound connections gets closed
and reused for outgoing connections (like rsh ends up doing for stderr
flow), current we may reject the SYN/ACK packet for the new connection
because tcp_conntracks states forbirds a port to become a client while
there is still a TIME_WAIT entry in there for it.
As TCP may expire the TIME_WAIT socket in 60s and conntrack's timeout
for it is 120s, there is a ~60s window that the application can end up
opening a port that conntrack will end up blocking.
This patch fixes this by simply allowing such state transition: if we
see a SYN, in TIME_WAIT state, on REPLY direction, move it to sSS. Note
that the rest of the code already handles this situation, more
specificly in tcp_packet(), first switch clause.
Signed-off-by: Marcelo Ricardo Leitner <mleitner@redhat.com>
Acked-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/netfilter/nf_conntrack_proto_tcp.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/net/netfilter/nf_conntrack_proto_tcp.c b/net/netfilter/nf_conntrack_proto_tcp.c index 44d1ea32570a..d87b6423ffb2 100644 --- a/net/netfilter/nf_conntrack_proto_tcp.c +++ b/net/netfilter/nf_conntrack_proto_tcp.c @@ -213,7 +213,7 @@ static const u8 tcp_conntracks[2][6][TCP_CONNTRACK_MAX] = { { /* REPLY */ /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ -/*syn*/ { sIV, sS2, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sS2 }, +/*syn*/ { sIV, sS2, sIV, sIV, sIV, sIV, sIV, sSS, sIV, sS2 }, /* * sNO -> sIV Never reached. * sSS -> sS2 Simultaneous open @@ -223,7 +223,7 @@ static const u8 tcp_conntracks[2][6][TCP_CONNTRACK_MAX] = { * sFW -> sIV * sCW -> sIV * sLA -> sIV - * sTW -> sIV Reopened connection, but server may not do it. + * sTW -> sSS Reopened connection, but server may have switched role * sCL -> sIV */ /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ |