A flaw in the Landlock LSM module allowed revoked privileges to be regained.
Jann Horn from the Google Project Zero team, who previously uncovered the Spectre and Meltdown vulnerabilities, has found a logical error in the implementation of the Linux Security Module (LSM) Landlock that allows a program to regain already dropped privileges if it has access to the system calls fork() and keyctl(). The Landlock mechanism enables unprivileged programs to drop unnecessary privileges needed for operation […]
