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Date: Wed, 24 Nov 2010 09:46:49 +0300
From: Dan Carpenter <error27@gmail.com>
To: Paul Mundt <lethal@linux-sh.org>
Cc: Vasiliy Kulikov <segoon@openwall.com>, kernel-janitors@vger.kernel.org,
        Jaya Kumar <jayalk@intworks.biz>, linux-fbdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] video: arcfb: fix buffer overflow
Message-ID: <20101124064649.GQ1522@bicker>
Mail-Followup-To: Dan Carpenter <error27@gmail.com>,
	Paul Mundt <lethal@linux-sh.org>,
	Vasiliy Kulikov <segoon@openwall.com>,
	kernel-janitors@vger.kernel.org, Jaya Kumar <jayalk@intworks.biz>,
	linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org
References: <1290361202-15065-1-git-send-email-segoon@openwall.com>
 <20101124062558.GF11705@linux-sh.org>
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On Wed, Nov 24, 2010 at 03:25:58PM +0900, Paul Mundt wrote:
> On Sun, Nov 21, 2010 at 08:40:01PM +0300, Vasiliy Kulikov wrote:
> > (count + p) is not checked for integer overflow.  If p < fbmemlength
> > and count == (size_t)(1 - p) (very big unsigned integer) then
> > count + p == 1 < fbmemlength and copy_to_user(base_addr+p, buf, count)
> > overflows base_addr.
> > 
> > Signed-off-by: Vasiliy Kulikov <segoon@openwall.com>
> 
> Applied, thanks.

The patch is harmless, but the integer overflow would actually be caught
in rw_verify_area().

regards,
dan carpenter

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