From: Florian Westphal <fwestphal@astaro.com>
Date: Thu, 17 Feb 2011 10:32:38 +0000 (+0100)
Subject: netfilter: tproxy: do not assign timewait sockets to skb->sk
X-Git-Tag: v2.6.38-rc7~47^2~19^2~1
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d503b30bd648b3cb4e5f50b65d27e389960cc6d9;p=pandora-kernel.git

netfilter: tproxy: do not assign timewait sockets to skb->sk

Assigning a socket in timewait state to skb->sk can trigger
kernel oops, e.g. in nfnetlink_log, which does:

if (skb->sk) {
        read_lock_bh(&skb->sk->sk_callback_lock);
        if (skb->sk->sk_socket && skb->sk->sk_socket->file) ...

in the timewait case, accessing sk->sk_callback_lock and sk->sk_socket
is invalid.

Either all of these spots will need to add a test for sk->sk_state != TCP_TIME_WAIT,
or xt_TPROXY must not assign a timewait socket to skb->sk.

This does the latter.

If a TW socket is found, assign the tproxy nfmark, but skip the skb->sk assignment,
thus mimicking behaviour of a '-m socket .. -j MARK/ACCEPT' re-routing rule.

The 'SYN to TW socket' case is left unchanged -- we try to redirect to the
listener socket.

Cc: Balazs Scheidler <bazsi@balabit.hu>
Cc: KOVACS Krisztian <hidden@balabit.hu>
Signed-off-by: Florian Westphal <fwestphal@astaro.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
---

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