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CVE-2024-40910 Affecting kernel-default-livepatch-devel package, versions <5.3.18-150300.59.174.1

Severity

 Recommended
0.0
high
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.04% (6th percentile)

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  • Snyk IDSNYK-SLES153-KERNELDEFAULTLIVEPATCHDEVEL-7985820
  • published17 Sept 2024
  • disclosed16 Sept 2024
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Introduced: 16 Sep 2024

CVE-2024-40910  (opens in a new tab)

How to fix?

Upgrade SLES:15.3 kernel-default-livepatch-devel to version 5.3.18-150300.59.174.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-default-livepatch-devel package and not the kernel-default-livepatch-devel package as distributed by SLES. See How to fix? for SLES:15.3 relevant fixed versions and status.

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

ax25: Fix refcount imbalance on inbound connections

When releasing a socket in ax25_release(), we call netdev_put() to decrease the refcount on the associated ax.25 device. However, the execution path for accepting an incoming connection never calls netdev_hold(). This imbalance leads to refcount errors, and ultimately to kernel crashes.

A typical call trace for the above situation will start with one of the following errors:

refcount_t: decrement hit 0; leaking memory.
refcount_t: underflow; use-after-free.

And will then have a trace like:

Call Trace:
&lt;TASK&gt;
? show_regs+0x64/0x70
? __warn+0x83/0x120
? refcount_warn_saturate+0xb2/0x100
? report_bug+0x158/0x190
? prb_read_valid+0x20/0x30
? handle_bug+0x3e/0x70
? exc_invalid_op+0x1c/0x70
? asm_exc_invalid_op+0x1f/0x30
? refcount_warn_saturate+0xb2/0x100
? refcount_warn_saturate+0xb2/0x100
ax25_release+0x2ad/0x360
__sock_release+0x35/0xa0
sock_close+0x19/0x20
[...]

On reboot (or any attempt to remove the interface), the kernel gets stuck in an infinite loop:

unregister_netdevice: waiting for ax0 to become free. Usage count = 0

This patch corrects these issues by ensuring that we call netdev_hold() and ax25_dev_hold() for new connections in ax25_accept(). This makes the logic leading to ax25_accept() match the logic for ax25_bind(): in both cases we increment the refcount, which is ultimately decremented in ax25_release().

CVSS Scores

version 3.1