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From: "David S. Miller" <davem@redhat.com>
To: Patrick McHardy <kaber@trash.net>
Cc: laforge@netfilter.org, okir@suse.de, netdev@oss.sgi.com,
	netfilter-devel@lists.netfilter.org
Subject: Re: [PATCH] Prevent crash on ip_conntrack removal
Date: Sat, 21 Aug 2004 22:13:44 -0700	[thread overview]
Message-ID: <20040821221344.6dbc98ed.davem@redhat.com> (raw)
In-Reply-To: <412765DC.30600@trash.net>

On Sat, 21 Aug 2004 17:10:20 +0200
Patrick McHardy <kaber@trash.net> wrote:

> David S. Miller wrote:
> 
> >I have a better idea.
> >
> >Instead of setting skb->dst to NULL, it should set it to some
> >NULL destination entry which just frees up the packets.  Then
> >no special case handling.  skb->dst==NULL packets should never
> >get into the fragment queue to begin with.
> >
> The problem is that conntrack unload can cause packets without a
> dst_entry to appear in ip_local_deliver, which is already after
> the call to dst_input.

How can it call ip_local_deliver() without a valid skb->dst?
That function is only invoked via skb->dst->input(skb) which
by implication means that skb->dst is non-NULL.

Actually there is a call via ip_mr_input() but that code also
has a precondition that skb->dst is non-NULL too.  I say this
due to the unchecked skb->dst accesses it makes early on.

Please explain.  I don't question that it happens, just show
me how :-)

  reply	other threads:[~2004-08-22  5:13 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-08-18  9:13 [PATCH] Prevent crash on ip_conntrack removal Olaf Kirch
2004-08-19 10:11 ` Harald Welte
2004-08-19 14:18   ` David S. Miller
2004-08-19 14:55     ` Patrick McHardy
2004-08-19 15:14       ` David S. Miller
2004-08-21 15:10         ` Patrick McHardy
2004-08-22  5:13           ` David S. Miller [this message]
2004-08-22 12:58             ` Patrick McHardy
2004-08-23  5:03               ` David S. Miller
2004-08-23 21:18               ` David Stevens
2004-08-24  0:45                 ` Nivedita Singhvi
2004-08-24  0:45                 ` Patrick McHardy
2004-08-24 21:28                   ` David Stevens
2004-08-29  6:15                     ` David S. Miller
2004-08-29 19:36                       ` Patrick McHardy
2004-08-29 19:57                         ` David S. Miller
2004-08-29 20:06                           ` Patrick McHardy
2004-08-29 21:58                           ` Patrick McHardy
2004-08-29 23:38                             ` David S. Miller
2004-08-30  0:50                               ` Patrick McHardy
2004-08-30  4:28                                 ` David S. Miller
2004-08-29 21:48                         ` Patrick McHardy
2004-08-30  7:57                         ` Olaf Kirch

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