linux-kernel - Re: [PATCH] fbdev: tgafb: Fix potential divide by zero

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Message-ID: <92a9d8d4-17e8-6906-7640-e7b82787f74a@gmx.de>
Date:   Thu, 9 Mar 2023 09:15:47 +0100
From:   Helge Deller <deller@....de>
To:     Jani Nikula <jani.nikula@...ux.intel.com>,
        harperchen <harperchen1110@...il.com>
Cc:     linux-fbdev@...r.kernel.org, javierm@...hat.com,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        wsa+renesas@...g-engineering.com, tzimmermann@...e.de
Subject: Re: [PATCH] fbdev: tgafb: Fix potential divide by zero

On 3/9/23 08:53, Jani Nikula wrote:
> On Wed, 08 Mar 2023, Helge Deller <deller@....de> wrote:
>> On 3/7/23 14:08, harperchen wrote:
>>> fb_set_var would by called when user invokes ioctl with cmd
>>> FBIOPUT_VSCREENINFO. User-provided data would finally reach
>>> tgafb_check_var. In case var->pixclock is assigned to zero,
>>> divide by zero would occur when checking whether reciprocal
>>> of var->pixclock is too high.
>>>
>>> Similar crashes have happened in other fbdev drivers. There
>>> is no check and modification on var->pixclock along the call
>>> chain to tgafb_check_var. We believe it could also be triggered
>>> in driver tgafb from user site.
>>>
>>> Signed-off-by: harperchen <harperchen1110@...il.com>
>>
>> Could you provide a real name?
>> Otherwise applied to fbdev git tree.
>
> See commit d4563201f33a ("Documentation: simplify and clarify DCO
> contribution example language").

Nice. Thanks for that link!
Btw, I did applied that patch yesterday to my tree with just the nickname,
but of course I do prefer real names which is why I asked.

Helge