netdev - Re: [PATCH] ipt_recent: fix race between recent_mt

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Date:	Wed, 30 Jul 2008 12:52:53 +0200
From:	Patrick McHardy <kaber@...sh.net>
To:	Pavel Emelyanov <xemul@...nvz.org>
CC:	David Miller <davem@...emloft.net>,
	Linux Netdev List <netdev@...r.kernel.org>,
	Netfilter Development Mailinglist 
	<netfilter-devel@...r.kernel.org>
Subject: Re: [PATCH] ipt_recent: fix race between recent_mt_destroy and proc
 manipulations

Pavel Emelyanov wrote:
> The thing is that recent_mt_destroy first flushes the entries
> from table with the recent_table_flush and only *after* this
> removes the proc file, corresponding to that table.
> 
> Thus, if we manage to write to this file the '+XXX' command we
> will leak some entries. If we manage to write there a 'clean'
> command we'll race in two recent_table_flush flows, since the
> recent_mt_destroy calls this outside the recent_lock.
> 
> The proper solution as I see it is to remove the proc file first
> and then go on with flushing the table. This flushing becomes
> safe w/o the lock, since the table is already inaccessible from
> the outside.

Applied, thanks.
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