Linux Kernel Uninitialized Variable Vulnerability in MediaTek MT6359 Auxiliary ADC Driver

A vulnerability exists in the Linux kernel's MediaTek MT6359 auxiliary ADC driver, specifically in the 'mt6358_read_imp()' function. The issue arises because the function reads a value into the variable 'val_v' using 'regmap_read()' without checking if the read operation was successful. If the read fails, 'val_v' remains uninitialized, and its random stack content is mistakenly reported as a measurement result. This flaw can lead to unintended data exposure. The vulnerability has been addressed by modifying the code to initialize 'val_v' to zero, ensuring that a predictable value is reported in the event of a bus failure. This change also prevents potential leakage of stack data and satisfies static analysis tools that may flag the variable as being used without initialization.

Impact

The vulnerability could result in the unintentional disclosure of random stack data, which could be misinterpreted as a valid measurement result.

Reproduction

To reproduce this vulnerability, use the MediaTek MT6359 auxiliary ADC driver in the Linux kernel. The 'mt6358_read_imp()' function will read a value into 'val_v' without verifying the success of the operation. If the read fails, 'val_v' will contain uninitialized data, which can be reported as a measurement result, leading to potential data leakage.

Remediation

The vulnerability has been fixed in the Linux kernel stable tree. Users can upgrade to the latest version to address this issue.