netdev - Re: use-after-free in sctp_do

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <566ED172.3000906@gmail.com>
Date:	Mon, 14 Dec 2015 09:25:54 -0500
From:	Vlad Yasevich <vyasevich@...il.com>
To:	David Laight <David.Laight@...LAB.COM>,
	Marcelo Ricardo Leitner <marcelo.leitner@...il.com>,
	Dmitry Vyukov <dvyukov@...gle.com>
Cc:	netdev <netdev@...r.kernel.org>,
	Eric Dumazet <eric.dumazet@...il.com>,
	syzkaller <syzkaller@...glegroups.com>,
	"linux-sctp@...r.kernel.org" <linux-sctp@...r.kernel.org>,
	Kostya Serebryany <kcc@...gle.com>,
	Alexander Potapenko <glider@...gle.com>,
	Sasha Levin <sasha.levin@...cle.com>
Subject: Re: use-after-free in sctp_do_sm

On 12/14/2015 04:50 AM, David Laight wrote:
> From: Vlad Yasevich
>> Sent: 11 December 2015 18:38
> ...
>>> Found a similar place in abort primitive handling like in this last
>>> patch update, it's probably the issue you're still triggering.
>>>
>>> Also found another place that may lead to this use after free, in case
>>> we receive a packet with a chunk that has no data.
>>>
>>> Oh my.. :)
>>
>> Yes.  This is what I was worried about...  Anything that triggers
>> a DELTE_TCB command has to return a code that we can trap.
>>
>> The other way is to do what Dmitri suggested, but even there, we
>> need to be very careful.
> 
> I'm always wary of anything that queues actions up for later processing.
> It is far too easy (as found here) to end up processing actions
> in invalid states, or to process actions in 'unusual' orders when
> specific events happen close together.
> 
> I wonder how much fallout there'd be from getting the sctp code
> to immediately action things, instead of queuing the actions for later.
> It would certainly remove a lot of the unusual combinations of events.
> 

We've bandied this idea around for a while, but no one has had the time
to tackle this.  This would be rather time-consuming task, but in the end
might be a good idea.

-vlad

> 	David
> 
> 

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html