linux-kernel - Re: [PATCH] fbdev: efifb: Fix a use-after-free due early fb

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]

Message-ID: <981d7ed4-8554-73ca-bfd1-2d89e4e91af3@redhat.com>
Date:   Sat, 7 May 2022 18:40:16 +0200
From:   Javier Martinez Canillas <javierm@...hat.com>
To:     Lucas De Marchi <lucas.demarchi@...el.com>
Cc:     linux-fbdev@...r.kernel.org,
        Andrzej Hajda <andrzej.hajda@...el.com>,
        Daniel Vetter <daniel.vetter@...ll.ch>,
        intel-gfx@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        dri-devel@...ts.freedesktop.org, Peter Jones <pjones@...hat.com>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Helge Deller <deller@....de>
Subject: Re: [PATCH] fbdev: efifb: Fix a use-after-free due early fb_info
 cleanup

Hello Lucas,

On 5/7/22 18:20, Lucas De Marchi wrote:
> On Fri, May 06, 2022 at 03:22:25PM +0200, Javier Martinez Canillas wrote:
>> Commit d258d00fb9c7 ("fbdev: efifb: Cleanup fb_info in .fb_destroy rather
>> than .remove") attempted to fix a use-after-free error due driver freeing
>> the fb_info in the .remove handler instead of doing it in .fb_destroy.
>>
>> But ironically that change introduced yet another use-after-free since the
>> fb_info was still used after the free.
>>
>> This should fix for good by freeing the fb_info at the end of the handler.
>>
>> Fixes: d258d00fb9c7 ("fbdev: efifb: Cleanup fb_info in .fb_destroy rather than .remove")
> 
> are these patches going through any CI before being applied? Maybe would
> be a good idea to cc intel-gfx mailing list on these fixes to have Intel
> CI to pick them up for some tests?
>

I Cc'ed intel-gfx for this particular patch. I should had done it for the
previous patches too, but I wasn't aware that Cc'ing that list would make
it run on your CI.

I tested locally the offending patch on an EFI platform before applying it
and I don't know why it didn't fail there. Sorry all for the inconvenience.
 
> pushed to drm-misc-fixes where the previous patch was applied.
> 

Thanks.

-- 
Best regards,

Javier Martinez Canillas
Linux Engineering
Red Hat