Hi Shuah, I got it. I'll try it. Best regards, Zheng Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx> 于2023年4月14日周五 02:01写道： > > On 4/13/23 02:09, Zheng Hacker wrote: > > Friendly ping about the issue. > > Sorry that I couldn't make test about the driver. > > > > Thanks, > > Zheng > > > > Zheng Hacker <hackerzheng666@xxxxxxxxx> 于2023年3月18日周六 15:39写道： > >> > >> Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx> 于2023年3月18日周六 06:53写道： > >>> > >>> On 3/17/23 04:09, Zheng Wang wrote: > >>>> In vudc_probe, it calls init_vudc_hw, which bound &udc->timer with v_timer. > >>>> > >>>> When it calls usbip_sockfd_store, it will call v_start_timer to start the > >>>> timer work. > >>>> > >>>> When we call vudc_remove to remove the driver, theremay be a sequence as > >>>> follows: > >>>> > >>>> Fix it by shutdown the timer work before cleanup in vudc_remove. > >>>> > >>>> Note that removing a driver is a root-only operation, and should never > >>>> happen. But the attacker can directly unplug the usb to trigger the remove > >>>> function. > >>>> > >>>> CPU0 CPU1 > >>>> > >>>> |v_timer > >>>> vudc_remove | > >>>> kfree(udc); | > >>>> //free shost | > >>>> |udc->gadget > >>>> |//use > >>>> > >>>> The udc might be removed before v_timer finished, and UAF happens. > >>>> > >>>> This bug was found by Codeql static analysis and might by false positive. > >>> > >>> This statement that this could be a false positive makes me hesitate > >>> taking this patch. > >>> > >>> What kind of testing have you done with this fix? Were you able to test > >>> the scenario of unplugging usb? > >>> > >> > >> Sorry I did't make a full test for I did't have the device. The > >> attacking scenario if based on other cases. > >> > > Sorry. I really need for you test this and provide information on how > it was tested. > > thanks, > -- Shuah >
