From: Florian Westphal <fw@strlen.de>
To: billbonaparte <programme110@gmail.com>
Cc: linux-kernel@vger.kernel.org,
'Netfilter Developer Mailing List'
<netfilter-devel@vger.kernel.org>,
'Pablo Neira Ayuso' <pablo@netfilter.org>,
'Patrick McHardy' <kaber@trash.net>,
kadlec@blackhole.kfki.hu, davem@davemloft.net,
'Changli Gao' <xiaosuo@gmail.com>,
'Jesper Dangaard Brouer' <brouer@redhat.com>,
'Andrey Vagin' <avagin@openvz.org>
Subject: Re: netfilter: nf_conntrack: there maybe a bug in __nf_conntrack_confirm, when it race against get_next_corpse
Date: Tue, 28 Oct 2014 10:46:12 +0100 [thread overview]
Message-ID: <20141028094612.GA14392@breakpoint.cc> (raw)
In-Reply-To: <02f201cff260$8622e610$9268b230$@gmail.com>
billbonaparte <programme110@gmail.com> wrote:
> In function __nf_conntrack_confirm, we check the conntrack if it was
> alreay dead, before insert it into hash-table.
> we do this because if we insert an already 'dead' hash, it will
> block further use of that particular connection.
> but we don't do that right.
Correct. This is broken since the central spin lock removal, since
nf_conntrack_lock no longer protects both get_next_corpse and
conntrack_confirm.
Please send a patch, moving dying check after removal of conntrack from
the percpu list, and add
Fixes: 93bb0ceb75be2 (netfilter: conntrack: remove central spinlock nf_conntrack_lock)
tag to patch.
> The above case reveal two problems:
> 1. we may insert a dead conntrack to hash-table, it will block
> further use of that particular connection.
Yes.
> 2. operation on ct->status should be atomic, because it race aginst
> get_next_corpse.
Alternatively we could also get rid of the unconfirmed list handling in
get_next_corpse, it looks to me as if its simply not worth the trouble
to also caring about unconfirmed lists.
next prev parent reply other threads:[~2014-10-28 9:46 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <02ef01cff25f$29887f60$7c997e20$@gmail.com>
2014-10-28 3:37 ` netfilter: nf_conntrack: there maybe a bug in __nf_conntrack_confirm, when it race against get_next_corpse billbonaparte
2014-10-28 9:46 ` Florian Westphal [this message]
2014-10-28 10:11 ` Jesper Dangaard Brouer
2014-11-07 6:47 Bill Bonaparte
[not found] <012601cff7d1$7ce2d620$76a88260$@gmail.com>
2014-11-06 13:00 ` Jesper Dangaard Brouer
-- strict thread matches above, loose matches on Subject: below --
2014-11-04 1:52 billbonaparte
2014-10-28 3:27 billbonaparte
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