Use After Free Affecting kernel-core package, versions <0:5.14.0-284.75.1.el9_2


Severity

Recommended
0.0
high
0
10

Based on Red Hat Enterprise Linux security rating

    Threat Intelligence

    EPSS
    0.04% (6th percentile)

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  • Snyk ID SNYK-RHEL9-KERNELCORE-7566621
  • published 25 Jul 2024
  • disclosed 20 Feb 2024

How to fix?

Upgrade RHEL:9 kernel-core to version 0:5.14.0-284.75.1.el9_2 or higher.
This issue was patched in RHSA-2024:4823.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-core package and not the kernel-core 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:

uio: Fix use-after-free in uio_open

core-1 core-2

uio_unregister_device uio_open idev = idr_find() device_unregister(&idev->dev) put_device(&idev->dev) uio_device_release get_device(&idev->dev) kfree(idev) uio_free_minor(minor) uio_release put_device(&idev->dev) kfree(idev)

In the core-1 uio_unregister_device(), the device_unregister will kfree idev when the idev->dev kobject ref is 1. But after core-1 device_unregister, put_device and before doing kfree, the core-2 may get_device. Then:

  1. After core-1 kfree idev, the core-2 will do use-after-free for idev.
  2. When core-2 do uio_release and put_device, the idev will be double freed.

To address this issue, we can get idev atomic & inc idev reference with minor_lock.

CVSS Scores

version 3.1
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NVD

7.8 high
  • Attack Vector (AV)
    Local
  • Attack Complexity (AC)
    Low
  • Privileges Required (PR)
    Low
  • User Interaction (UI)
    None
  • Scope (S)
    Unchanged
  • Confidentiality (C)
    High
  • Integrity (I)
    High
  • Availability (A)
    High
Expand this section

Red Hat

7 high
Expand this section

SUSE

6.7 medium