linux-kernel - Re: [PATCH] arm: put_user: fix possible data corruption in put

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]

Date:	Mon, 5 May 2014 09:45:19 -0400 (EDT)
From:	Nicolas Pitre <nicolas.pitre@...aro.org>
To:	Andrey Ryabinin <a.ryabinin@...sung.com>
cc:	Russell King - ARM Linux <linux@....linux.org.uk>,
	Will Deacon <will.deacon@....com>,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] arm: put_user: fix possible data corruption in
 put_user

On Mon, 5 May 2014, Andrey Ryabinin wrote:

> On 05/05/14 13:01, Russell King - ARM Linux wrote:
> > On Mon, May 05, 2014 at 10:13:58AM +0400, Andrey Ryabinin wrote:
> >> According to arm procedure call standart r2 register is call-cloberred.
> >> So after the result of x expression was put into r2 any following
> >> function call in p may overwrite r2. To fix this, the result of p
> >> expression must be saved to the temporary variable before the
> >> assigment x expression to __r2.
> > 
> > This and the patch make no sense.  You talk about r2, but you're doing
> > nothing with r2 in the patch.
> > 
> 
> No, you didn't get it. I'll try to explain better.
> 
> Lets consider following example:
[...]

Thanks for the test code.  I do confirm there is indeed a problem.

I'm trying to make sure your patch is actually the best fix.


Nicolas
--
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/