linux-kernel - Re: FW: [PATCH] cs5535_gpio: Fix root triggerable integer underflow

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:	Fri, 24 Jul 2009 21:00:55 +0200
From:	Michael Buesch <mb@...sch.de>
To:	Ben Gardner <gardner.ben@...il.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: FW: [PATCH] cs5535_gpio: Fix root triggerable integer underflow

On Friday 24 July 2009 19:40:28 Ben Gardner wrote:
> Hi Michael,
> 
> > This patch fixes a possible root triggerable (I hope the device is only
> > readable by root?) integer underflow.
> > Well, it's not really an underflow, but as loff_t is a signed type, the
> > range check at the start of the function is incomplete. It needs to
> > check for <0, too.
> > Otherwise the loop below will poke into random memory and I/O space.
> > This could be used to crash the machine, at least.
> >
> > This patch is only compiletested, because I do not have the hardware.
> >
> > Signed-off-by: Michael Buesch <mb@...sch.de>
> >
> > ---
> >
> > I'm not sure if this bug is exploitable. I _guess_ the device is only
> > readable by root
> > on a standard setup.
> 
> The cs5525_gpio driver uses the default seek, which doesn't allow
> negative position values.
> So, I don't think it necessary to check for negative values.

Yes you are right.

-- 
Greetings, Michael.
--
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/