Deadlock Affecting kernel-modules-extra package, versions *


Severity

Recommended
0.0
medium
0
10

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.04% (11th percentile)

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  • Snyk IDSNYK-RHEL9-KERNELMODULESEXTRA-7089095
  • published24 May 2024
  • disclosed21 May 2024

Introduced: 21 May 2024

CVE-2021-47225  (opens in a new tab)
CWE-833  (opens in a new tab)

How to fix?

There is no fixed version for RHEL:9 kernel-modules-extra.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-modules-extra package and not the kernel-modules-extra package as distributed by RHEL. See How to fix? for RHEL:9 relevant fixed versions and status.

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

CVSS Scores

version 3.1