From: Eric Dumazet <eric.dumazet@gmail.com>
To: Tim Chen <tim.c.chen@linux.intel.com>
Cc: "Yan, Zheng" <zheng.z.yan@intel.com>,
"Yan, Zheng" <yanzheng@21cn.com>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"davem@davemloft.net" <davem@davemloft.net>,
"sfr@canb.auug.org.au" <sfr@canb.auug.org.au>,
"jirislaby@gmail.com" <jirislaby@gmail.com>,
"sedat.dilek@gmail.com" <sedat.dilek@gmail.com>,
"Shi, Alex" <alex.shi@intel.com>,
Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Subject: Re: [PATCH -next v2] unix stream: Fix use-after-free crashes
Date: Wed, 07 Sep 2011 23:26:06 +0200 [thread overview]
Message-ID: <1315430766.2532.1.camel@edumazet-laptop> (raw)
In-Reply-To: <1315396903.2364.23.camel@schen9-mobl>
Le mercredi 07 septembre 2011 à 05:01 -0700, Tim Chen a écrit :
> On Wed, 2011-09-07 at 09:45 +0200, Eric Dumazet wrote:
> > Le mercredi 07 septembre 2011 à 13:20 +0800, Yan, Zheng a écrit :
> >
> > > Is code like this OK? Thanks
> > > ---
> > > if (sent + size < len) {
> > > /* Only send the fds in the first buffer */
> > > /* get additional ref if more skbs will be created */
> > > err = unix_scm_to_skb(siocb->scm, skb, !fds_sent, true);
> > > } else {
> > > err = unix_scm_to_skb(siocb->scm, skb, !fds_sent, false);
> > > ref_avail = false;
> > > }
> > >
> > >
> >
> > Whats wrong with using ref_avail in the unix_scm_to_skb() call itself ?
> >
> > something like :
> >
>
> Eric,
>
> Your updated patch looks good when I tested it on my side. It makes the
> patch much more readable. If this patch looks good with you and Yan
> Zheng, can you and Yan Zheng add your Signed-off-by to the patch?
>
> Jiri, Sedat or Valdis, if you can verify that the patch fixed commit
> 0856a30409, that will be appreciated.
>
> Eric, are you planning to do a fast path patch that doesn't do pid ref
> for the case where CONFIG_PID_NS is not set?
>
Yes, I'll try to cook a patch.
> Thanks.
>
> Tim
>
> ---
>
> Commit 0856a30409 (Scm: Remove unnecessary pid & credential references
> in Unix socket's send and receive path) introduced a use-after-free bug.
> The sent skbs from unix_stream_sendmsg could be consumed and destructed
> by the receive side, removing all references to the credentials,
> before the send side has finished sending out all
> packets. However, send side could continue to consturct new packets in the
> stream, using credentials that have lost its last reference and been
> freed.
>
> In this fix, we don't steal the reference to credentials we have obtained
> in scm_send at beginning of unix_stream_sendmsg, till we've reached
> the last packet. This fixes the problem in commit 0856a30409.
>
> Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
> Reported-by: Jiri Slaby <jirislaby@gmail.com>
> Tested-by: Sedat Dilek <sedat.dilek@googlemail.com>
> Tested-by: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
> ---
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Thanks !
next prev parent reply other threads:[~2011-09-07 21:26 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-04 5:44 [PATCH -next v2] unix stream: Fix use-after-free crashes Yan, Zheng
2011-09-04 7:12 ` Sedat Dilek
2011-09-04 8:23 ` Yan, Zheng
2011-09-04 15:50 ` Joe Perches
2011-09-06 16:39 ` Tim Chen
2011-09-06 16:25 ` Tim Chen
2011-09-06 17:40 ` Eric Dumazet
2011-09-06 18:50 ` Tim Chen
2011-09-06 19:01 ` Eric Dumazet
2011-09-06 19:33 ` Tim Chen
2011-09-06 19:43 ` Eric Dumazet
2011-09-06 19:59 ` Tim Chen
2011-09-06 20:19 ` Eric Dumazet
2011-09-06 22:08 ` Tim Chen
2011-09-07 2:35 ` Eric Dumazet
2011-09-06 23:09 ` Yan, Zheng
2011-09-07 2:55 ` Eric Dumazet
2011-09-16 23:35 ` David Miller
2011-09-16 16:50 ` Tim Chen
2011-09-19 7:57 ` Eric Dumazet
2011-09-07 4:36 ` Yan, Zheng
2011-09-07 5:08 ` Eric Dumazet
2011-09-07 5:20 ` Yan, Zheng
[not found] ` <1315381503.3400.85.camel@edumazet-laptop>
2011-09-07 12:01 ` Tim Chen
2011-09-07 20:12 ` Sedat Dilek
2011-09-07 20:30 ` Sedat Dilek
2011-09-07 14:37 ` Tim Chen
2011-09-08 0:27 ` Yan, Zheng
2011-09-07 21:06 ` Tim Chen
2011-09-07 21:15 ` Tim Chen
2011-09-08 6:21 ` Eric Dumazet
2011-09-08 4:18 ` Yan, Zheng
2011-09-08 5:59 ` Eric Dumazet
2011-09-08 6:22 ` Yan, Zheng
2011-09-08 7:11 ` Eric Dumazet
2011-09-08 7:23 ` Yan, Zheng
2011-09-08 7:33 ` Eric Dumazet
2011-09-08 9:59 ` Sedat Dilek
2011-09-08 13:21 ` [PATCH net-next v3] af_unix: " Eric Dumazet
2011-09-08 8:37 ` Tim Chen
2011-09-09 6:51 ` Eric Dumazet
2011-09-09 7:58 ` [PATCH net-next] af_unix: fix use after free in unix_stream_recvmsg() Eric Dumazet
2011-09-09 10:39 ` Tim Chen
2011-09-09 10:41 ` [PATCH net-next v3] af_unix: Fix use-after-free crashes Tim Chen
2011-09-08 7:56 ` [PATCH -next v2] unix stream: " Jiri Slaby
2011-09-08 8:43 ` Sedat Dilek
2011-09-08 7:02 ` Sedat Dilek
2011-09-07 21:26 ` Eric Dumazet [this message]
2011-09-08 13:28 ` Eric Dumazet
2011-09-08 9:24 ` Tim Chen
2011-09-09 5:06 ` [PATCH net-next] af_unix: dont send SCM_CREDENTIALS by default Eric Dumazet
2011-09-12 19:15 ` Tim Chen
2011-09-19 1:07 ` David Miller
2011-09-19 4:28 ` Eric Dumazet
2011-09-19 15:02 ` Eric Dumazet
2011-09-19 15:52 ` [PATCH v2 " Eric Dumazet
2011-09-19 21:39 ` Tim Chen
2011-09-20 2:10 ` Valdis.Kletnieks
2011-09-20 4:16 ` Eric Dumazet
2011-09-22 16:15 ` tim
2011-11-28 13:23 ` Michal Schmidt
2011-11-28 13:38 ` Eric Dumazet
2011-09-28 17:30 ` David Miller
2011-09-08 10:05 ` [PATCH -next v2] unix stream: Fix use-after-free crashes Sedat Dilek
2011-09-08 8:50 ` Tim Chen
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