Arend van Spriel arend.vanspriel@broadcom.com 于2023年11月13日周一 17:18写道：
On November 8, 2023 4:03:26 AM Zheng Hacker hackerzheng666@gmail.com wrote:
Arend Van Spriel arend.vanspriel@broadcom.com 于2023年11月6日周一 23:48写道：
On November 6, 2023 3:44:53 PM Zheng Hacker hackerzheng666@gmail.com wrote:
Thanks! I didn't test it for I don't have a device. Very appreciated if anyone could help with that.
I would volunteer, but it made me dig deep and not sure if there is a problem to solve here.
brcmf_cfg80211_detach() calls wl_deinit_priv() -> brcmf_abort_scanning() -> brcmf_notify_escan_complete() which does delete the timer.
What am I missing here?
Thanks four your detailed review. I did see the code and not sure if brcmf_notify_escan_complete would be triggered for sure. So in the first version I want to delete the pending timer ahead of time.
Why requesting a CVE when you are not sure? Seems a bit hasty to put it mildly.
I'm sure the issue exists because there's only cancler of timer but not woker. As there's similar CVEs before like : https://github.com/V4bel/CVE-2022-41218, I submit it as soon as I found it.
As I'm not very familiar with the logic here. I'm still not sure if we should delete the timer_shutdown_sync. Looking forward to your reply :)
Reading the kerneldoc of timer_shutdown_sync() has the advantage that the timer can not be rearmed by another thread. However, that will only happen when a new scan is initiated in firmware, but the bus is already down so that can not happen. The only improvement (no bug fix!) I see here is to replace timer handling code in brcmf_notify_escan_complete():
if (timer_pending(&cfg->escan_timeout))del_timer_sync(&cfg->escan_timeout);
timer_delete_sync(&cfg->escan_timeout);
Very thanks for your reviews and suggestions! I thinks it's a good idea. I'll make another patch sooner or later.
Best regards, Zheng
Regards, Arend