From: Tim Chen <tim.c.chen@linux.intel.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: "Yan, Zheng" <zheng.z.yan@intel.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>,
alex.shi@intel.com
Subject: Re: [PATCH -next v2] unix stream: Fix use-after-free crashes
Date: Tue, 06 Sep 2011 12:33:00 -0700 [thread overview]
Message-ID: <1315337580.2576.3066.camel@schen9-DESK> (raw)
In-Reply-To: <1315335660.3400.7.camel@edumazet-laptop>
On Tue, 2011-09-06 at 21:01 +0200, Eric Dumazet wrote:
> > All the skbs put on the list does have proper reference on pid/scm. In
> > the example you give, the first skb got the reference at this line:
> >
> > err = unix_scm_to_skb(siocb->scm, skb, !fds_sent, fds_sent);
>
> This is the current code. We know its buggy.
>
> I was discussing of things after proposed patch, not current net-next.
I think we are on the same page.
> My approach would basically revert the 7361c36c commit too :(
I think so. I was not fond of commit 7361c36c as it caused a 90%
regression in threaded case of hackbench that we noticed back in 2.6.36
days. If there's some way to undo its evil, I'm all for it.
>
> I am sorry, but the only way to avoid too many pid/cred references is to
> lock the socket [aka unix_state_lock(other);] for the whole send()
> duration.
Yes, I think locking the sendmsg for the entire duration of
unix_stream_sendmsg makes a lot of sense. It simplifies the logic a lot
more. I'll try to cook something up in the next couple of days.
>
> This way, you can really increment the pid/cred reference on the last
> pushed skb, because no reader can 'catch first skb'
>
> As soon as unix_state_unlock(other) is called, everything can happen, so
> skb must be self contained, as I stated in my earlier mail.
>
>
>
Thanks.
Tim
next prev parent reply other threads:[~2011-09-06 19:30 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 [this message]
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
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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