netdev - Re: Simple kernel attack using socketpair. easy, 100% reproductiblle, works under guest. no way to protect :(

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] [day] [month] [year] [list]

Message-ID: <1291053718.3435.1275.camel@edumazet-laptop>
Date:	Mon, 29 Nov 2010 19:01:58 +0100
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	David Miller <davem@...emloft.net>
Cc:	socketpair@...il.com, netdev@...r.kernel.org
Subject: Re: Simple kernel attack using socketpair. easy, 100%
 reproductiblle, works under guest. no way to protect :(

Le lundi 29 novembre 2010 à 09:46 -0800, David Miller a écrit :
> From: Eric Dumazet <eric.dumazet@...il.com>
> Date: Thu, 25 Nov 2010 15:11:39 +0100
> 
> > [PATCH] af_unix: limit recursion level
> > 
> > Its easy to eat all kernel memory and trigger NMI watchdog, using an
> > exploit program that queues unix sockets on top of others.
> > 
> > lkml ref : http://lkml.org/lkml/2010/11/25/8
> > 
> > This mechanism is used in applications, one choice we have is to have a
> > recursion limit.
> > 
> > Other limits might be needed as well (if we queue other types of files),
> > since the passfd mechanism is currently limited by socket receive queue
> > sizes only.
> > 
> > Add a recursion_level to unix socket, allowing up to 4 levels.
> > 
> > Each time we send an unix socket through sendfd mechanism, we copy its
> > recursion level (plus one) to receiver. This recursion level is cleared
> > when socket receive queue is emptied.
> > 
> > Reported-by: Марк Коренберг <socketpair@...il.com>
> > Signed-off-by: Eric Dumazet <eric.dumazet@...il.com>
> 
> Ok, since such deep recursive AF_UNIX fd sends is pretty
> rediculious, it seems this is not likely to hit legitimate
> use cases and thus I've applied this.
> 
> Also queued up for -stable.
> 
> Thanks!

I tested FreeBSD (latest) and got a kernel freeze as well with exploit
program.

I dont know yet how to fully fix this problem.



--
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