From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1755639AbdKJCFP (ORCPT <rfc822;w@1wt.eu>);
        Thu, 9 Nov 2017 21:05:15 -0500
Received: from [128.1.224.119] ([128.1.224.119]:35654 "EHLO ringil.hmeau.com"
        rhost-flags-FAIL-FAIL-OK-OK) by vger.kernel.org with ESMTP
        id S1755440AbdKJCFO (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Thu, 9 Nov 2017 21:05:14 -0500
Date: Fri, 10 Nov 2017 13:04:59 +1100
From: Herbert Xu <herbert@gondor.apana.org.au>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: syzbot 
        <bot+413384116f7f7dab7903d54c53fc4af6a4441965@syzkaller.appspotmail.com>,
        David Miller <davem@davemloft.net>,
        LKML <linux-kernel@vger.kernel.org>, netdev <netdev@vger.kernel.org>,
        Steffen Klassert <steffen.klassert@secunet.com>,
        syzkaller-bugs@googlegroups.com
Subject: Re: kernel BUG at net/key/af_key.c:LINE!
Message-ID: <20171110020459.GA22329@gondor.apana.org.au>
References: <001a114a958ce46160055c4c4f66@google.com>
 <CACT4Y+b9+1AAJk5Jxddae5okBXo9oaKu0m8gzbgyEnzGByY1hg@mail.gmail.com>
 <20171108074742.GA28177@gondor.apana.org.au>
 <CACT4Y+a_0grrUjrovW=0=0UPkH3pE_HpncDc3uBzwR_YtDURPA@mail.gmail.com>
 <20171109113857.GA15280@gondor.apana.org.au>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20171109113857.GA15280@gondor.apana.org.au>
User-Agent: Mutt/1.5.21 (2010-09-15)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Thu, Nov 09, 2017 at 10:38:57PM +1100, Herbert Xu wrote:
> 
> The xfrm code path is meant to forbid the creation of such a policy.
> I don't currently see how this is bypassing that check.  But
> clearly it has found a way through the check since it's crashing.

By castrating the reproducer to not perform a pfkey dump I have
captured the corrupted policy via xfrm:

src ???/0 dst ???/0 uid 0
        socket in action allow index 2083 priority 0 ptype main share any flag  (0x00000000)
        lifetime config:
          limit: soft 0(bytes), hard 0(bytes)
          limit: soft 0(packets), hard 0(packets)
          expire add: soft 0(sec), hard 0(sec)
          expire use: soft 0(sec), hard 0(sec)
        lifetime current:
          0(bytes), 0(packets)
          add 2017-11-10 09:58:17 use 2017-11-10 09:58:20
        tmpl src ac14:bb:: dst ::
                proto 0 spi 0x00000000(0) reqid 0(0x00000000) mode transport
                level 5 share any 
                enc-mask 00000000 auth-mask 00000000 comp-mask 00000000

For comparison here is a good policy that was also created by the
reproducer:

src fe80::bb/0 dst ::/0 uid 0
        socket in action allow index 2083 priority 0 ptype main share any flag  (0x00000000)
        lifetime config:
          limit: soft 0(bytes), hard 0(bytes)
          limit: soft 0(packets), hard 0(packets)
          expire add: soft 0(sec), hard 0(sec)
          expire use: soft 0(sec), hard 0(sec)
        lifetime current:
          0(bytes), 0(packets)
          add 2017-11-10 09:58:17 use 2017-11-10 09:58:17
        tmpl src ac14:bb:: dst ::
                proto 0 spi 0x00000000(0) reqid 0(0x00000000) mode transport
                level 5 share any 
                enc-mask 00000000 auth-mask 00000000 comp-mask 00000000

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt