netdev - Re: Fwd: 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] [thread-next>] [day] [month] [year] [list]

Message-ID: <4CEF39AF.6090605@cn.fujitsu.com>
Date:	Fri, 26 Nov 2010 12:38:07 +0800
From:	Shan Wei <shanwei@...fujitsu.com>
To:	Eric Dumazet <eric.dumazet@...il.com>
CC:	Марк Коренберг 
	<socketpair@...il.com>, David Miller <davem@...emloft.net>,
	netdev@...r.kernel.org
Subject: Re: Fwd: Simple kernel attack using socketpair. easy, 100% reproductiblle,
 works under guest. no way to protect :(

Eric Dumazet wrote, at 11/25/2010 10:11 PM:
> Le jeudi 25 novembre 2010 à 13:35 +0500, Марк Коренберг a écrit :
>> quick and dirty fix will be not to allow to pass unix socket inside
>> unix socket. I think it would not break much applications.
> 
> Really, if it was not needed, net/unix/garbage.c would not exist at
> all...
> 
> It is needed by some apps.
> 
> 
> [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>

This problem is same as that reported with title "Unix socket local DOS (OOM)", right?
After applied this patch, this program can be killed now. but still eat 100% cpu. 

-- 
Best Regards
-----
Shan Wei
--
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