CVE-2021-47225: mac80211: fix deadlock in AP/VLAN handling
First published: Tue May 21 2024(Updated: )
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
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Linux Kernel | ||
| Linux Kernel | >=5.12<5.12.13 | |
| Linux Kernel | =5.13-rc1 | |
| Linux Kernel | =5.13-rc2 | |
| Linux Kernel | =5.13-rc3 | |
| Linux Kernel | =5.13-rc4 | |
| Linux Kernel | =5.13-rc5 | |
| Linux Kernel | =5.13-rc6 |
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Reference Links
Frequently Asked Questions
What is the severity of CVE-2021-47225?
CVE-2021-47225 has been reported to have a moderate severity due to the potential for deadlock conditions in specific configurations.
How do I fix CVE-2021-47225?
To address CVE-2021-47225, update the Linux kernel to a patched version that resolves the deadlock issue.
What systems are affected by CVE-2021-47225?
CVE-2021-47225 affects Linux kernel versions from 5.12 up to and including 5.13-rc6.
What is the impact of CVE-2021-47225?
CVE-2021-47225 can lead to a deadlock situation when managing AP/VLAN interfaces, disrupting network operations.
Is there a workaround for CVE-2021-47225 until I can update?
There are no recommended workarounds for CVE-2021-47225, making it essential to update to a fixed version.
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- version/linux kernel/5.12
- version/linux kernel/5.13-rc1
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- version/linux kernel/5.13-rc5
- version/linux kernel/5.13-rc6