Re: [PATCH] vc_screen: don't clobber return value in vcs_read

[Linux regression tracking (Thorsten Leemhuis)]

On 27.02.23 20:59, George Kennedy wrote:
> Hello Thomas,
> 
> On 2/27/2023 9:20 AM, Linux regression tracking (Thorsten Leemhuis) wrote:
>> Hi, this is your Linux kernel regression tracker. Top-posting for once,
>> to make this easily accessible to everyone.
>>
>> George, is there anything we can do to help you moving forward to
>> finally get this regression fixed? It seems (or am I missing something?)
>> everyone is waiting for you (see below) to act on the feedback Jiri
>> provided here:
>>
>> https://lore.kernel.org/lkml/8dffe187-240d-746e-ed84-885ffd2785f6@xxxxxxxxxx/
>>
>> Side note: would be good to add a "Link:" tag pointing to the start of
>> this thread as well, but that's just a detail.
> 
> I just sent the requested patch up for review.
> 
> https://lore.kernel.org/lkml/1677527001-17459-1-git-send-email-george.kennedy@xxxxxxxxxx/

Thx for handling this!

And I see it very quickly made its way to mainline. :-D

Ciao, Thorsten

>> On 21.02.23 14:50, Greg Kroah-Hartman wrote:
>>> On Tue, Feb 21, 2023 at 08:30:11AM -0500, George Kennedy wrote:
>>>> On 2/20/2023 11:34 AM, Thomas Weißschuh wrote:
>>>>> +Cc people who were involved in the original thread.
>>>>>
>>>>> On Mon, Feb 20, 2023 at 12:48:59PM +0100, Jiri Slaby wrote:
>>>>>> On 20. 02. 23, 7:46, linux@xxxxxxxxxxxxxx wrote:
>>>>>>> From: Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
>>>>>>>
>>>>>>> Commit 226fae124b2d
>>>>>>> ("vc_screen: move load of struct vc_data pointer in vcs_read() to
>>>>>>> avoid UAF")
>>>>>>> moved the call to vcs_vc() into the loop.
>>>>>>> While doing this it also moved the unconditional assignment of
>>>>>>> "ret = -ENXIO".
>>>>>>> This unconditional assignment was valid outside the loop but
>>>>>>> within it
>>>>>>> it clobbers the actual value of ret.
>>>>>>>
>>>>>>> To avoid this only assign "ret = -ENXIO" when actually needed.
>>>>>> Not sure -- I cannot find it -- but hasn't George fixed this yet?
>>>>> Indeed there was a proposed fix at
>>>>> https://lore.kernel.org/lkml/1675704844-17228-1-git-send-email-george.kennedy@xxxxxxxxxx/
>>>>>
>>>>> Linus had some suggestions so it was not applied as is.
>>>>>
>>>>> I'm not sure what the current state is.
>>>>> George, do you have something in the pipeline?
>>>> Yes, that is in the pipeline:
>>>> https://lore.kernel.org/lkml/1675774098-17722-1-git-send-email-george.kennedy@xxxxxxxxxx/
>>>>
>>>> Linus suggested the fix, which was tested and submitted.
>>>>
>>>> Jiri commented on the patch, which I believe was directed at Linus
>>>> as he
>>>> suggested the fix.
>>> And I was waiting for a new version from you based on those comments :(
>>>
>>> Can you fix that up and send?
>>>
>>> thanks,
>>>
>>> greg k-h
>> #regzbot monitor:
>> https://lore.kernel.org/lkml/1675774098-17722-1-git-send-email-george.kennedy@xxxxxxxxxx/
>> #regzbot poke
> 
> 
>