Use After Free Affecting kernel-tools package, versions <0:4.18.0-193.el8


Severity

Recommended
high

Based on Red Hat Enterprise Linux security rating

    Threat Intelligence

    EPSS
    0.05% (16th percentile)

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  • Snyk ID SNYK-RHEL8-KERNELTOOLS-3753453
  • published 26 Jul 2021
  • disclosed 25 Nov 2019

How to fix?

Upgrade RHEL:8 kernel-tools to version 0:4.18.0-193.el8 or higher.
This issue was patched in RHSA-2020:1769.

NVD Description

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

There is a use-after-free in kernel versions before 5.5 due to a race condition between the release of ptp_clock and cdev while resource deallocation. When a (high privileged) process allocates a ptp device file (like /dev/ptpX) and voluntarily goes to sleep. During this time if the underlying device is removed, it can cause an exploitable condition as the process wakes up to terminate and clean all attached files. The system crashes due to the cdev structure being invalid (as already freed) which is pointed to by the inode.

CVSS Scores

version 3.1
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NVD

6.4 medium
  • Attack Vector (AV)
    Local
  • Attack Complexity (AC)
    High
  • Privileges Required (PR)
    High
  • User Interaction (UI)
    None
  • Scope (S)
    Unchanged
  • Confidentiality (C)
    High
  • Integrity (I)
    High
  • Availability (A)
    High
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Red Hat

6.5 medium
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SUSE

6.4 medium