Linux Kernel Memory Leak Vulnerability in DRM Client Target Cloned Function

A memory leak vulnerability has been identified in the Linux kernel's Direct Rendering Manager (DRM) client handling, specifically within the 'drm_client_target_cloned' function. This issue arises because the 'dmt_mode' variable is allocated memory that is never released. While this vulnerability was discovered in the AST graphics driver, it is likely to affect other drivers that use the generic framebuffer (fbdev) setup. The vulnerability has been addressed by modifying the code to ensure that the allocated memory is properly freed, preventing the memory leak.

Impact

Exploitation of this vulnerability leads to a memory leak, where allocated memory is not properly released, potentially causing increased memory usage and degradation of system performance over time.

Reproduction

The vulnerability can be reproduced by using a Linux kernel version that includes the affected 'drm_client_target_cloned' function. When this function is called, the 'dmt_mode' variable is allocated but not freed, leading to a memory leak. This issue can be observed in the kernel's memory management subsystem, specifically within the Direct Rendering Manager's client handling for drivers that utilize the generic framebuffer setup.

Remediation

Users can upgrade to the latest version of the Linux kernel where this vulnerability has been fixed. The official Linux kernel Git repository includes the patched version. Instructions for downloading the latest stable kernel can be found on the official Linux kernel website.