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Date: Tue, 20 Feb 2024 08:11:53 +0300
From: Dan Carpenter <dan.carpenter@linaro.org>
To: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: gustavo@embeddedor.com, keescook@chromium.org,
	Gerd Hoffmann <kraxel@redhat.com>,
	Sumit Semwal <sumit.semwal@linaro.org>,
	Christian =?iso-8859-1?Q?K=F6nig?= <christian.koenig@amd.com>,
	Daniel Vetter <daniel.vetter@ffwll.ch>,
	linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org,
	dri-devel@lists.freedesktop.org, linux-media@vger.kernel.org,
	linaro-mm-sig@lists.linaro.org
Subject: Re: [PATCH v2] udmabuf: Fix a potential (and unlikely) access to
 unallocated memory
Message-ID: <bc59a084-73bb-46a8-b02b-0ef990020458@moroto.mountain>
References: <f75d0426a17b57dbddacd7da345c1c62a3dbb7ce.1708278363.git.christophe.jaillet@wanadoo.fr>
 <91d964c2-3d5a-4e96-a4db-e755455c5b5c@moroto.mountain>
 <3fe4c327-b69b-464e-8e4e-005fa1813279@wanadoo.fr>
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In-Reply-To: <3fe4c327-b69b-464e-8e4e-005fa1813279@wanadoo.fr>

On Mon, Feb 19, 2024 at 06:59:02PM +0100, Christophe JAILLET wrote:
> Le 19/02/2024 ? 09:37, Dan Carpenter a ?crit?:
> > On Sun, Feb 18, 2024 at 06:46:44PM +0100, Christophe JAILLET wrote:
> > > If 'list_limit' is set to a very high value, 'lsize' computation could
> > > overflow if 'head.count' is big enough.
> > > 
> > 
> > The "list_limit" is set via module parameter so if you set that high
> > enough to lead to an integer overflow then you kind of deserve what
> > you get.
> > 
> > This patch is nice for kernel hardening and making the code easier to
> > read/audit but the real world security impact is negligible.
> 
> Agreed.
> 
> That is what I meant by "and unlikely".
> Maybe the commit message could be more explicit if needed.
> 
> Let me know if ok as-is or if I should try to re-word the description.

No, it's fine.  But in the future if there is an integer overflow then
lets mention in the commit message who it affects or what the impact is.

regards,
dan carpenter