diff options
| author | Jozsef Kadlecsik <kadlec@blackhole.kfki.hu> | 2007-10-11 14:35:52 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2007-10-11 14:35:52 -0700 |
| commit | 17311393f969090ab060540bd9dbe7dc885a76d5 (patch) | |
| tree | cc8f9a460679870c51b194c8927f998b243a98f7 /net | |
| parent | d71fce6b932d83e0a1caa49dfa5a536fd50f07c9 (diff) | |
| download | linux-17311393f969090ab060540bd9dbe7dc885a76d5.tar.gz linux-17311393f969090ab060540bd9dbe7dc885a76d5.tar.bz2 linux-17311393f969090ab060540bd9dbe7dc885a76d5.zip | |
[NETFILTER]: nf_conntrack_tcp: fix connection reopening
With your description I could reproduce the bug and actually you were
completely right: the code above is incorrect. Somehow I was able to
misread RFC1122 and mixed the roles :-(:
When a connection is >>closed actively<<, it MUST linger in
TIME-WAIT state for a time 2xMSL (Maximum Segment Lifetime).
However, it MAY >>accept<< a new SYN from the remote TCP to
reopen the connection directly from TIME-WAIT state, if it:
[...]
The fix is as follows: if the receiver initiated an active close, then the
sender may reopen the connection - otherwise try to figure out if we hold
a dead connection.
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Tested-by: Krzysztof Piotr Oledzki <ole@ans.pl>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/netfilter/nf_conntrack_proto_tcp.c | 35 |
1 files changed, 14 insertions, 21 deletions
diff --git a/net/netfilter/nf_conntrack_proto_tcp.c b/net/netfilter/nf_conntrack_proto_tcp.c index df718e7c7ee4..c7075345971b 100644 --- a/net/netfilter/nf_conntrack_proto_tcp.c +++ b/net/netfilter/nf_conntrack_proto_tcp.c @@ -831,6 +831,20 @@ static int tcp_packet(struct nf_conn *conntrack, tuple = &conntrack->tuplehash[dir].tuple; switch (new_state) { + case TCP_CONNTRACK_SYN_SENT: + if (old_state < TCP_CONNTRACK_TIME_WAIT) + break; + if (conntrack->proto.tcp.seen[!dir].flags & + IP_CT_TCP_FLAG_CLOSE_INIT) { + /* Attempt to reopen a closed connection. + * Delete this connection and look up again. */ + write_unlock_bh(&tcp_lock); + if (del_timer(&conntrack->timeout)) + conntrack->timeout.function((unsigned long) + conntrack); + return -NF_REPEAT; + } + /* Fall through */ case TCP_CONNTRACK_IGNORE: /* Ignored packets: * @@ -879,27 +893,6 @@ static int tcp_packet(struct nf_conn *conntrack, nf_log_packet(pf, 0, skb, NULL, NULL, NULL, "nf_ct_tcp: invalid state "); return -NF_ACCEPT; - case TCP_CONNTRACK_SYN_SENT: - if (old_state < TCP_CONNTRACK_TIME_WAIT) - break; - if ((conntrack->proto.tcp.seen[dir].flags & - IP_CT_TCP_FLAG_CLOSE_INIT) - || after(ntohl(th->seq), - conntrack->proto.tcp.seen[dir].td_end)) { - /* Attempt to reopen a closed connection. - * Delete this connection and look up again. */ - write_unlock_bh(&tcp_lock); - if (del_timer(&conntrack->timeout)) - conntrack->timeout.function((unsigned long) - conntrack); - return -NF_REPEAT; - } else { - write_unlock_bh(&tcp_lock); - if (LOG_INVALID(IPPROTO_TCP)) - nf_log_packet(pf, 0, skb, NULL, NULL, - NULL, "nf_ct_tcp: invalid SYN"); - return -NF_ACCEPT; - } case TCP_CONNTRACK_CLOSE: if (index == TCP_RST_SET && ((test_bit(IPS_SEEN_REPLY_BIT, &conntrack->status) |