CVE-2021-47412 Affecting kernel-rt-kvm package, versions <0:4.18.0-553.22.1.rt7.363.el8_10


Severity

Recommended
high

Based on Rocky Linux security rating.

Threat Intelligence

EPSS
0.04% (11th percentile)

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  • Snyk IDSNYK-ROCKY8-KERNELRTKVM-8133865
  • published1 Oct 2024
  • disclosed21 May 2024

Introduced: 21 May 2024

CVE-2021-47412  (opens in a new tab)

How to fix?

Upgrade Rocky-Linux:8 kernel-rt-kvm to version 0:4.18.0-553.22.1.rt7.363.el8_10 or higher.
This issue was patched in RLSA-2024:7001.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-rt-kvm package and not the kernel-rt-kvm package as distributed by Rocky-Linux. See How to fix? for Rocky-Linux:8 relevant fixed versions and status.

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

block: don't call rq_qos_ops->done_bio if the bio isn't tracked

rq_qos framework is only applied on request based driver, so:

  1. rq_qos_done_bio() needn't to be called for bio based driver

  2. rq_qos_done_bio() needn't to be called for bio which isn't tracked, such as bios ended from error handling code.

Especially in bio_endio():

  1. request queue is referred via bio->bi_bdev->bd_disk->queue, which may be gone since request queue refcount may not be held in above two cases

  2. q->rq_qos may be freed in blk_cleanup_queue() when calling into __rq_qos_done_bio()

Fix the potential kernel panic by not calling rq_qos_ops->done_bio if the bio isn't tracked. This way is safe because both ioc_rqos_done_bio() and blkcg_iolatency_done_bio() are nop if the bio isn't tracked.

CVSS Scores

version 3.1