Linux Kernel DMA Channel Offset Calculation Vulnerability in SH3, SH4, and SH4A SoCs

A vulnerability exists in the Linux kernel's DMA driver for certain SH3, SH4, and SH4A SoCs. These systems can have varying numbers of DMA channels, which may be split between two DMAC modules. The current driver implementation does not properly account for these differences, leading to incorrect channel offset calculations. This flaw can cause kernel panics by disrupting normal operations. The issue arises because the driver fails to accommodate the unique DMA channel configurations of these processors, particularly when channels are distributed across multiple DMAC modules.

Impact

The vulnerability can cause kernel panics, disrupting system stability and operation.

Reproduction

The vulnerability can be reproduced by using a Linux kernel version that includes the flawed DMA driver for SH3, SH4, or SH4A SoCs. When the system attempts to manage DMA channels, the incorrect offset calculations will lead to a kernel panic.

Remediation

Users can upgrade to the latest version of the Linux kernel, where this vulnerability has been addressed. Instructions for downloading the patched version are available on the official Linux kernel website.