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. > > Best regads, > Zheng > > > thanks, > > -- Shuah
