Summary: MTE As Implemented

Project Zero gained access to ARM MTE hardware in mid-2022, allowing them to assess its effectiveness in preventing memory-safety vulnerability exploitation. Despite its limitations, MTE is considered the most promising approach for improving C/C++ software security in 2023, offering superior detection of memory corruption at the initial dangerous access. While MTE won't completely eliminate exploitable memory safety issues, especially considering speculative side-channel attacks, it provides a broader impact on exploitability than other practical proposals. The blog post argues that software solutions for C/C++ memory safety with comparable coverage to MTE are unlikely to achieve lower runtime overhead than AddressSanitizer/HWAsan, which is too high for most production workloads. Products expecting to maintain large C/C++ codebases and considering memory corruption exploitation a key security risk are advised to actively support ARM's MTE. The blog series includes an objective summary of implementation testing, providing technical background for those interested in implementing MTE-based mitigations. It also offers subjective assessments of various MTE-based mitigation approaches in user-mode contexts and discusses additional challenges faced when using MTE for kernel-mode mitigation. The series aims to provide a comprehensive overview of MTE's potential impact on software security and its practical implementation considerations.