CVE-2023-53484: linux kernel Use-After-Free — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: lib: cpu_rmap: Avoid use after free on rmap->obj array entries When calling irq_set_affinity_notifier() with NULL at the notify argument, it will cause freeing of the glue pointer in the corresponding array entry but will leave the pointer in the array. A subsequent call to free_irq_cpu_rmap() will try to free this entry again leading to possible use after free. Fix that by setting NULL to the array entry and checking that we have non-zero at the array entry when iterating over the array in free_irq_cpu_rmap(). The current code does not suffer from this since there are no cases where irq_set_affinity_notifier(irq, NULL) (note the NULL passed for the notify arg) is called, followed by a call to free_irq_cpu_rmap() so we don't hit and issue. Subsequent patches in this series excersize this flow, hence the required fix.

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CVSS v3.1 Score

7.8

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Weakness Type (CWE)

CWE-416 Use After Free

Affected Products

Vendor	Product	Versions
linux	linux_kernel	3.8.1 — 4.14.316
linux	linux_kernel	4.15 — 4.19.284
linux	linux_kernel	4.20 — 5.4.244
linux	linux_kernel	5.5 — 5.10.181
linux	linux_kernel	5.11 — 5.15.113
linux	linux_kernel	5.16 — 6.1.30
linux	linux_kernel	6.2 — 6.3.4
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All

References

Advisories & Patches

https://git.kernel.org/stable/c/4e0473f1060aa49621d40a113afde24818101d37 https://git.kernel.org/stable/c/67bca5f1d644f4e79b694abd8052a177de81c37f https://git.kernel.org/stable/c/981f339d2905b6a92ef59358158b326493aecac5 https://git.kernel.org/stable/c/c6ed54dd90698dc0744d669524cc1c122ded8a16 https://git.kernel.org/stable/c/c9115f49cf260d24d8b5f2d9a4b63cb31a627bb4 https://git.kernel.org/stable/c/cc2d2b3dbfb0ba57bc027fb7e1121250c50e4000 https://git.kernel.org/stable/c/d1308bd0b24cb1d78fa2747d5fa3e055cc628a48 https://git.kernel.org/stable/c/f748e15253833b771acbede14ea98f50831ac289

Frequently Asked Questions

What is CVE-2023-53484? +

In the Linux kernel, the following vulnerability has been resolved: lib: cpu_rmap: Avoid use after free on rmap->obj array entries When calling irq_set_affinity_notifier() with NULL at the notify argument, it will cause freeing of the glue pointer in the corresponding array entry but will leave the pointer in the array. A subsequent call to free_irq_cpu_rmap() will try to free this entry again leading to possible use after free. Fix that by setting NULL to the array entry and checking that we have non-zero at the array entry when iterating over the array in free_irq_cpu_rmap(). The current code does not suffer from this since there are no cases where irq_set_affinity_notifier(irq, NULL) (note the NULL passed for the notify arg) is called, followed by a call to free_irq_cpu_rmap() so we don't hit and issue. Subsequent patches in this series excersize this flow, hence the required fix. It has a CVSS v3.1 base score of 7.8 (HIGH).

How severe is CVE-2023-53484? +

CVE-2023-53484 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2023-53484? +

CVE-2023-53484 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2023-53484? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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