CVE-2023-53095: linux kernel Null Dereference — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: drm/ttm: Fix a NULL pointer dereference The LRU mechanism may look up a resource in the process of being removed from an object. The locking rules here are a bit unclear but it looks currently like res->bo assignment is protected by the LRU lock, whereas bo->resource is protected by the object lock, while *clearing* of bo->resource is also protected by the LRU lock. This means that if we check that bo->resource points to the LRU resource under the LRU lock we should be safe. So perform that check before deciding to swap out a bo. That avoids dereferencing a NULL bo->resource in ttm_bo_swapout().

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CVSS v3.1 Score

5.5

MEDIUM

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

Weakness Type (CWE)

CWE-476 CWE-476

Affected Products

Vendor	Product	Versions
linux	linux_kernel	5.19 — 6.1.21
linux	linux_kernel	6.2 — 6.2.8
linux	linux_kernel	All
linux	linux_kernel	All

References

Advisories & Patches

https://git.kernel.org/stable/c/9a9a8fe26751334b7739193a94eba741073b8a55 https://git.kernel.org/stable/c/9ba1720f6c4a0f13c3f3cb5c28132ee75555d04f https://git.kernel.org/stable/c/9d9b1f9f7a72d83ebf173534e76b246349f32374

Frequently Asked Questions

What is CVE-2023-53095? +

In the Linux kernel, the following vulnerability has been resolved: drm/ttm: Fix a NULL pointer dereference The LRU mechanism may look up a resource in the process of being removed from an object. The locking rules here are a bit unclear but it looks currently like res->bo assignment is protected by the LRU lock, whereas bo->resource is protected by the object lock, while *clearing* of bo->resource is also protected by the LRU lock. This means that if we check that bo->resource points to the LRU resource under the LRU lock we should be safe. So perform that check before deciding to swap out a bo. That avoids dereferencing a NULL bo->resource in ttm_bo_swapout(). It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2023-53095? +

CVE-2023-53095 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2023-53095? +

CVE-2023-53095 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-2023-53095? +

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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