From: Cong Wang <xiyou.wangcong@gmail.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Anoob Soman <anoob.soman@citrix.com>,
Dmitry Vyukov <dvyukov@google.com>,
David Miller <davem@davemloft.net>,
Willem de Bruijn <willemb@google.com>,
Eric Dumazet <edumazet@google.com>,
Daniel Borkmann <daniel@iogearbox.net>,
jarno@ovn.org, Sowmini Varadhan <sowmini.varadhan@oracle.com>,
Philip Pettersson <philip.pettersson@gmail.com>,
weongyo.linux@gmail.com, netdev <netdev@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
syzkaller <syzkaller@googlegroups.com>
Subject: Re: net/packet: use-after-free in packet_rcv_fanout
Date: Fri, 10 Feb 2017 10:34:03 -0800 [thread overview]
Message-ID: <CAM_iQpVaCDtP8-1AoVUVAB+-jM7rcLBj4wgo8-qp2WMCP5U8PQ@mail.gmail.com> (raw)
In-Reply-To: <1486749763.7793.152.camel@edumazet-glaptop3.roam.corp.google.com>
On Fri, Feb 10, 2017 at 10:02 AM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> On Fri, 2017-02-10 at 09:59 -0800, Eric Dumazet wrote:
>> On Fri, 2017-02-10 at 09:49 -0800, Cong Wang wrote:
>> > On Thu, Feb 9, 2017 at 7:23 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
>> > > On Thu, 2017-02-09 at 19:19 -0800, Eric Dumazet wrote:
>> > >
>> > >> More likely the bug is in fanout_add(), with a buggy sequence in error
>> > >> case, and not correct locking.
>> > >>
>> > >> kfree(po->rollover);
>> > >> po->rollover = NULL;
>> > >>
>> > >> Two cpus entering fanout_add() (using the same af_packet socket,
>> > >> syzkaller courtesy...) might both see po->fanout being NULL.
>> > >>
>> > >> Then they grab the mutex. Too late...
>> > >
>> > > Patch could be :
>> > >
>> >
>> > For me, clearly the data structure that use-after-free'd is struct sock
>> > rather than struct packet_rollover.
>>
>> Fine. But your patch makes absolutely no sense.
>
> At least, Anoob patch is making a step into the right direction ;)
>
> https://patchwork.ozlabs.org/patch/726532/
>
Yeah, but still looks like a different one with the one Dmitry reported.
next prev parent reply other threads:[~2017-02-10 18:34 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-09 13:14 net/packet: use-after-free in packet_rcv_fanout Dmitry Vyukov
2017-02-09 15:12 ` Sowmini Varadhan
2017-02-09 15:17 ` Eric Dumazet
2017-02-10 1:24 ` Cong Wang
2017-02-10 3:19 ` Eric Dumazet
2017-02-10 3:23 ` Eric Dumazet
2017-02-10 17:49 ` Cong Wang
2017-02-10 17:59 ` Eric Dumazet
2017-02-10 18:02 ` Cong Wang
2017-02-10 18:15 ` Eric Dumazet
2017-02-10 18:02 ` Eric Dumazet
2017-02-10 18:34 ` Cong Wang [this message]
2017-02-13 1:42 ` Sowmini Varadhan
2017-02-13 15:17 ` Dmitry Vyukov
2017-02-17 19:27 ` Cong Wang
2017-02-10 3:33 ` Sowmini Varadhan
2017-02-10 4:18 ` Eric Dumazet
2017-02-10 18:00 ` Cong Wang
2017-02-10 19:16 ` Sowmini Varadhan
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