Out-of-bounds Read Affecting kernel-tools package, versions <0:4.18.0-477.67.1.el8_8


Severity

Recommended
high

Based on Red Hat Enterprise Linux security rating

    Threat Intelligence

    EPSS
    0.05% (17th percentile)

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  • Snyk ID SNYK-RHEL8-KERNELTOOLS-7685245
  • published 14 Aug 2024
  • disclosed 1 May 2024

How to fix?

Upgrade RHEL:8 kernel-tools to version 0:4.18.0-477.67.1.el8_8 or higher.
This issue was patched in RHSA-2024:5255.

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.

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

Squashfs: check the inode number is not the invalid value of zero

Syskiller has produced an out of bounds access in fill_meta_index().

That out of bounds access is ultimately caused because the inode has an inode number with the invalid value of zero, which was not checked.

The reason this causes the out of bounds access is due to following sequence of events:

  1. Fill_meta_index() is called to allocate (via empty_meta_index()) and fill a metadata index. It however suffers a data read error and aborts, invalidating the newly returned empty metadata index. It does this by setting the inode number of the index to zero, which means unused (zero is not a valid inode number).

  2. When fill_meta_index() is subsequently called again on another read operation, locate_meta_index() returns the previous index because it matches the inode number of 0. Because this index has been returned it is expected to have been filled, and because it hasn't been, an out of bounds access is performed.

This patch adds a sanity check which checks that the inode number is not zero when the inode is created and returns -EINVAL if it is.

[phillip@squashfs.org.uk: whitespace fix] Link: https://lkml.kernel.org/r/20240409204723.446925-1-phillip@squashfs.org.uk

CVSS Scores

version 3.1
Expand this section

Red Hat

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

SUSE

5.5 medium