Linux Kernel Vulnerability in UFS Driver for Google gs101

CVE-2025-39788

What is CVE-2025-39788?

A vulnerability has been identified in the Linux kernel affecting the UFS driver on Google gs101. This issue arises from the incorrect programming of the UTRL_NEXUS_TYPE due to improper shift operations. The driver attempts to set the number of UTP transfer request slots incorrectly by shifting the value of 1, which leads to undefined behavior as the shift exceeds the width of the integer type. The flaw has been addressed by employing the BIT() macro for proper type casting, ensuring that the value written to UTRL_NEXUS_TYPE is correct (0xffffffff on gs101). This fix also resolves a UBSAN shift warning related to out-of-bounds shifts, contributing to the stability and security of the system.

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