linux-kernel - Re: [PATCH] SYSVIPC - Fix the ipc structures initialization

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]

Date:	Thu, 13 Nov 2008 18:53:57 +0100
From:	Manfred Spraul <manfred@...orfullife.com>
To:	Nadia Derbey <Nadia.Derbey@...l.net>
CC:	Andrew Morton <akpm@...ux-foundation.org>, cboulte@...il.com,
	linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...e.hu>
Subject: Re: [PATCH] SYSVIPC - Fix the ipc structures initialization

Nadia Derbey wrote:
> That's what the patch I sent at the beginning of this thread
> (http://lkml.org/lkml/2008/10/28/177) fixes: the ipc structure is not
> completely initialized before being inserted in the tree.
>
> The patched kernel has been running for 4 days on my victim without any
> problem, but Clement is still facing a problem (that comes later).
>
> I think this patch should be included anyways, because ipc structures
> initialization is not correct the way it is done today.
>
>   
Definitively: Your patch belongs into 2.6.28 and the next 2.6.27.

> I'm still reviewing the code to see what else could be wrong.
>   
I started looking into the idr code: perhaps idr returns a stale entry? 
A race somewhere in the RCU code.
I.e. the new bug is not corruption due to access before 
spin_lock_init(), but due to access after kfree()?

Clement: Could you send us an ipcs output from before the test?
Do you have any sysv msg queues on your system?
And: Do you use PREEMPT, do you use PREEMPT_RCU?

If there are no message queues around, then every msgget()/IPC_RMID will 
create a new idr layer/tear the layer down again.

--
    Manfred
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/