Linux Kernel up to 6.1.20/6.2.7 ttm_bo_swapout null pointer dereference

Summaryinfo

A vulnerability described as critical has been identified in Linux Kernel up to 6.1.20/6.2.7. This issue affects the function ttm_bo_swapout. Such manipulation leads to null pointer dereference. This vulnerability is documented as CVE-2023-53095. There is not any exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.1.20/6.2.7 and classified as critical. Affected by this issue is the function ttm_bo_swapout. The manipulation with an unknown input leads to a null pointer dereference vulnerability. Using CWE to declare the problem leads to CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. Impacted is availability. CVE summarizes:

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().

The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2023-53095 since 05/02/2025. There are known technical details, but no exploit is available.

Upgrading to version 6.1.21 or 6.2.8 eliminates this vulnerability. Applying the patch 9ba1720f6c4a0f13c3f3cb5c28132ee75555d04f/9d9b1f9f7a72d83ebf173534e76b246349f32374/9a9a8fe26751334b7739193a94eba741073b8a55 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.1.0
• 6.1.1
• 6.1.2
• 6.1.3
• 6.1.4
• 6.1.5
• 6.1.6
• 6.1.7
• 6.1.8
• 6.1.9
• 6.1.10
• 6.1.11
• 6.1.12
• 6.1.13
• 6.1.14
• 6.1.15
• 6.1.16
• 6.1.17
• 6.1.18
• 6.1.19
• 6.1.20
• 6.2.0
• 6.2.1
• 6.2.2
• 6.2.3
• 6.2.4
• 6.2.5
• 6.2.6
• 6.2.7

License

• open-source

Website

• Vendor: https://www.kernel.org/

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