From: ebiederm@xmission•com (Eric W. Biederman)
To: David Miller <davem@davemloft•net>
Cc: fw@strlen•de, netfilter-devel@vger•kernel.org, netdev@vger•kernel.org
Subject: Re: [PATCH nf-next] netns: add and use net_ns_barrier
Date: Wed, 31 May 2017 12:46:00 -0500 [thread overview]
Message-ID: <87mv9skjhj.fsf@xmission.com> (raw)
In-Reply-To: <20170531.125527.1553231867217469072.davem@davemloft.net> (David Miller's message of "Wed, 31 May 2017 12:55:27 -0400 (EDT)")
David Miller <davem@davemloft•net> writes:
> From: Florian Westphal <fw@strlen•de>
> Date: Tue, 30 May 2017 11:38:12 +0200
>
>> Quoting Joe Stringer:
>> If a user loads nf_conntrack_ftp, sends FTP traffic through a network
>> namespace, destroys that namespace then unloads the FTP helper module,
>> then the kernel will crash.
>>
>> Events that lead to the crash:
>> 1. conntrack is created with ftp helper in netns x
>> 2. This netns is destroyed
>> 3. netns destruction is scheduled
>> 4. netns destruction wq starts, removes netns from global list
>> 5. ftp helper is unloaded, which resets all helpers of the conntracks
>> via for_each_net()
>>
>> but because netns is already gone from list the for_each_net() loop
>> doesn't include it, therefore all of these conntracks are unaffected.
>>
>> 6. helper module unload finishes
>> 7. netns wq invokes destructor for rmmod'ed helper
>>
>> CC: "Eric W. Biederman" <ebiederm@xmission•com>
>> Reported-by: Joe Stringer <joe@ovn•org>
>> Signed-off-by: Florian Westphal <fw@strlen•de>
>> ---
>> Eric, I'd like an explicit (n)ack from you for this one.
>
> Indeed, Eric, please do.
Taking a look now. The original didn't make it's way into my inbox. I
just have a copy from netdev. Florian there may be a bit of an email
black hole between us.
> Otherwise I'm fine with the generic parts:
>
> Acked-by: David S. Miller <davem@davemloft•net>
Eric
next prev parent reply other threads:[~2017-05-31 17:52 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-30 9:38 [PATCH nf-next] netns: add and use net_ns_barrier Florian Westphal
2017-05-31 16:55 ` David Miller
2017-05-31 17:46 ` Eric W. Biederman [this message]
2017-05-31 18:13 ` Eric W. Biederman
2017-05-31 20:21 ` Joe Stringer
2017-06-01 8:52 ` Florian Westphal
2017-06-12 21:47 ` Cong Wang
2017-06-13 6:16 ` Florian Westphal
2017-06-13 16:35 ` Cong Wang
2017-06-13 18:07 ` Florian Westphal
2017-06-13 19:27 ` Joe Stringer
2017-06-13 21:16 ` Cong Wang
2017-06-14 8:41 ` Pablo Neira Ayuso
2017-06-14 14:20 ` Eric W. Biederman
2017-06-12 8:47 ` Pablo Neira Ayuso
2017-06-02 9:38 ` David Laight
2017-06-02 9:53 ` Florian Westphal
2017-06-19 17:10 ` Pablo Neira Ayuso
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