NULL Pointer Dereference Affecting kernel-default-livepatch package, versions <5.14.21-150400.24.122.2


Severity

Recommended
0.0
medium
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.04% (11th percentile)

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  • Snyk IDSNYK-SLES154-KERNELDEFAULTLIVEPATCH-7390812
  • published26 Jun 2024
  • disclosed25 Jun 2024

Introduced: 25 Jun 2024

CVE-2021-47556  (opens in a new tab)
CWE-476  (opens in a new tab)

How to fix?

Upgrade SLES:15.4 kernel-default-livepatch to version 5.14.21-150400.24.122.2 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-default-livepatch package and not the kernel-default-livepatch package as distributed by SLES. See How to fix? for SLES:15.4 relevant fixed versions and status.

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

ethtool: ioctl: fix potential NULL deref in ethtool_set_coalesce()

ethtool_set_coalesce() now uses both the .get_coalesce() and .set_coalesce() callbacks. But the check for their availability is buggy, so changing the coalesce settings on a device where the driver provides only one of the callbacks results in a NULL pointer dereference instead of an -EOPNOTSUPP.

Fix the condition so that the availability of both callbacks is ensured. This also matches the netlink code.

Note that reproducing this requires some effort - it only affects the legacy ioctl path, and needs a specific combination of driver options:

  • have .get_coalesce() and .coalesce_supported but no .set_coalesce(), or
  • have .set_coalesce() but no .get_coalesce(). Here eg. ethtool doesn't cause the crash as it first attempts to call ethtool_get_coalesce() and bails out on error.

CVSS Scores

version 3.1