Linux Kernel up to 5.17.1 link_enc_cfg_copy null pointer dereference

Summaryinfo

A vulnerability was found in Linux Kernel up to 5.17.1. It has been classified as critical. This impacts the function link_enc_cfg_copy. The manipulation leads to null pointer dereference. This vulnerability is traded as CVE-2022-49203. There is no exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Linux Kernel up to 5.17.1. It has been rated as critical. This issue affects the function link_enc_cfg_copy. 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. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Fix double free during GPU reset on DC streams [Why] The issue only occurs during the GPU reset code path. We first backup the current state prior to commiting 0 streams internally from DM to DC. This state backup contains valid link encoder assignments. DC will clear the link encoder assignments as part of current state (but not the backup, since it was a copied before the commit) and free the extra stream reference it held. DC requires that the link encoder assignments remain cleared/invalid prior to commiting. Since the backup still has valid assignments we call the interface post reset to clear them. This routine also releases the extra reference that the link encoder interface held - resulting in a double free (and eventually a NULL pointer dereference). [How] We'll have to do a full DC commit anyway after GPU reset because the stream count previously went to 0. We don't need to retain the assignment that we had backed up, so just copy off of the now clean current state assignment after the reset has occcurred with the new link_enc_cfg_copy() interface.

The advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2022-49203 since 02/26/2025. Technical details are known, but no exploit is available.

Upgrading to version 5.17.2 eliminates this vulnerability. Applying the patch bbfcdd6289ba6f00f0cd7d496946dce9f6c600ac/32685b32d825ca08c5dec826477332df886c4743 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

• 5.17.0
• 5.17.1

License

• open-source

Website

• Vendor: https://www.kernel.org/

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