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redhatcveRedhat.comRH:CVE-2021-47225
HistoryMay 23, 2024 - 1:59 p.m.

CVE-2021-47225

2024-05-2313:59:58
redhat.com
access.redhat.com
1
linux kernel
vulnerability
mac80211
ap/vlan
deadlock
syzbot reports
wiphy mutex
cfg80211
dev_close()

6.4 Medium

AI Score

Confidence

Low

0.0004 Low

EPSS

Percentile

9.0%

In the Linux kernel, the following vulnerability has been resolved: mac80211: fix deadlock in AP/VLAN handling Syzbot reports that when you have AP_VLAN interfaces that are up and close the AP interface they belong to, we get a deadlock. No surprise - since we dev_close() them with the wiphy mutex held, which goes back into the netdev notifier in cfg80211 and tries to acquire the wiphy mutex there. To fix this, we need to do two things: 1) prevent changing iftype while AP_VLANs are up, we can’t easily fix this case since cfg80211 already calls us with the wiphy mutex held, but change_interface() is relatively rare in drivers anyway, so changing iftype isn’t used much (and userspace has to fall back to down/change/up anyway) 2) pull the dev_close() loop over VLANs out of the wiphy mutex section in the normal stop case

6.4 Medium

AI Score

Confidence

Low

0.0004 Low

EPSS

Percentile

9.0%