Re: [PATCH] Revert "Input: bcm5974 - check endpoint type before starting traffic"

[Javier Carrasco <javier.carrasco.cruz@gmail.com>]

On 05.03.24 07:20, Linux regression tracking (Thorsten Leemhuis) wrote:
> On 05.03.24 06:52, Javier Carrasco wrote:
>> This patch intended to fix an well-knonw issue in old drivers where the
>> endpoint type is taken for granted, which is often triggered by fuzzers.
>>
>> That was the case for this driver [1], and although the fix seems to be
>> correct, it uncovered another issue that leads to a regression [2] if
>> the endpoints of the current interface are checked. The driver makes use
>> of endpoints that belong to a different interface rather than the one it
>> binds (it binds to the third interface, but also accesses an endpoint
>> from a different one). The driver should claim the interfaces it
>> requires, but that is still not the case.
>>
>> Given that the regression is more severe than the issue found by
>> syzkaller, the best approach is reverting the patch that causes the
>> regression, and trying to fix the underlying problem before checking
>> the endpoint types again.
>>
>> Note that reverting this patch will probably trigger the syzkaller bug
>> at some point.
>>> [1] https://syzkaller.appspot.com/bug?extid=348331f63b034f89b622
>> [2] https://lore.kernel.org/linux-input/ab9d758c-3ce9-42f6-99af-877055a589e6@leemhuis.info/T/#t
> 
> FWIW, these should be Link: or Closes tags, as explained in the docs.
> And there is a better lore link. And there is the bugzilla entry as well.
> Hence...
>  
>> This reverts commit 2b9c3eb32a699acdd4784d6b93743271b4970899.
>>
>> Fixes: b516b1b0dfcc ("Revert "Input: bcm5974 - check endpoint type before starting traffic"")
> 
> you might want to add them here like this:
> 
>  Link: https://syzkaller.appspot.com/bug?extid=348331f63b034f89b622 [1]
>  Link: https://lore.kernel.org/linux-input/87sf161jjc.wl-tiwai@suse.de/ [2]
>  Link: https://bugzilla.suse.com/show_bug.cgi?id=1220030
> 
> In an ideal world we also would add a "Reported-by: Jacopo Radice" before
> the bugzilla line, as the details in the suse bugtracker apparently is
> public, but it's likely better to not go down that path.
> 
>> Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
> 
> Ciao, Thorsten

Thanks for your comments, I will apply those changes right away and add
the "Repported-by:" tag as well.

Best regards,
Javier Carrasco