This is a note to let you know that we have just queued up the patch titled
Subject: NETFILTER: nf_conntrack_tcp: fix connection reopening
to the 2.6.23-stable tree. Its filename is
netfilter-nf_conntrack_tcp-fix-connection-reopening.patch
A git repo of this tree can be found at
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
>From stable-bounces@xxxxxxxxxxxxxxxx Mon Nov 5 03:38:25 2007
From: Jozsef Kadlecsik <kadlec@xxxxxxxxxxxxxxxxx>
Date: Mon, 05 Nov 2007 12:37:55 +0100
Subject: NETFILTER: nf_conntrack_tcp: fix connection reopening
To: stable@xxxxxxxxxx
Cc: Netfilter Development Mailinglist <netfilter-devel@xxxxxxxxxxxxxxx>, "David S. Miller" <davem@xxxxxxxxxxxxx>, Krzysztof Piotr Oledzki <ole@xxxxxx>, Jozsef Kadlecsik <kadlec@xxxxxxxxxxxxxxxxx>
Message-ID: <472F0093.6040508@xxxxxxxxx>
From: Jozsef Kadlecsik <kadlec@xxxxxxxxxxxxxxxxx>
Upstream commits: 17311393 + bc34b841 merged together. Merge done by
Patrick McHardy <kaber@xxxxxxxxx>
[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@xxxxxxxxxxxxxxxxx>
Tested-by: Krzysztof Piotr Oledzki <ole@xxxxxx>
Signed-off-by: Patrick McHardy <kaber@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
net/netfilter/nf_conntrack_proto_tcp.c | 38 ++++++++++++++-------------------
1 file changed, 17 insertions(+), 21 deletions(-)
--- a/net/netfilter/nf_conntrack_proto_tcp.c
+++ b/net/netfilter/nf_conntrack_proto_tcp.c
@@ -831,6 +831,22 @@ static int tcp_packet(struct nf_conn *co
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)
+ || (conntrack->proto.tcp.last_dir == dir
+ && conntrack->proto.tcp.last_index == TCP_RST_SET)) {
+ /* Attempt to reopen a closed/aborted 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 +895,6 @@ static int tcp_packet(struct nf_conn *co
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)
@@ -932,6 +927,7 @@ static int tcp_packet(struct nf_conn *co
in_window:
/* From now on we have got in-window packets */
conntrack->proto.tcp.last_index = index;
+ conntrack->proto.tcp.last_dir = dir;
pr_debug("tcp_conntracks: ");
NF_CT_DUMP_TUPLE(tuple);
Patches currently in stable-queue which might be from kadlec@xxxxxxxxxxxxxxxxx are
queue-2.6.23/netfilter-nf_conntrack_tcp-fix-connection-reopening.patch
-
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