CVE-2022-49394

Technical Description

In the Linux kernel, the following vulnerability has been resolved:

blk-iolatency: Fix inflight count imbalances and IO hangs on offline

iolatency needs to track the number of inflight IOs per cgroup. As this

tracking can be expensive, it is disabled when no cgroup has iolatency

configured for the device. To ensure that the inflight counters stay

balanced, iolatency_set_limit() freezes the request_queue while manipulating

the enabled counter, which ensures that no IO is in flight and thus all

counters are zero.

Unfortunately, iolatency_set_limit() isn't the only place where the enabled

counter is manipulated. iolatency_pd_offline() can also dec the counter and

trigger disabling. As this disabling happens without freezing the q, this

can easily happen while some IOs are in flight and thus leak the counts.

This can be easily demonstrated by turning on iolatency on an one empty

cgroup while IOs are in flight in other cgroups and then removing the

cgroup. Note that iolatency shouldn't

Remediation

Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Affected Products

References