Write Permissions for Locking and Badblock Ioctls

CVE-2021-47055

Summary

A vulnerability in the Linux kernel relates to improper access control for memory management functionality. Specifically, functions like MEMLOCK, MEMUNLOCK, and OTPLOCK, which adjust protection bits, require write permissions to function correctly. In certain hardware implementations, such as SPI-NOR flash memory, MEMLOCK may exhibit a write-once characteristic due to the write-protect (WP#) line being tied to ground. Additionally, the MEMSETBADBLOCK function that modifies the bad block table does not adequately enforce permission checks. These oversights can lead to unauthorized access or modification of critical memory operations, compromising system stability and security.

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