The Open Source Technology Improvement Fund is proud to share the results of our security work on the BOLT binary scanner for LLVM. LLVM is an open source compiler for translating human-readable source code for machine-readable hardware. In 2024, Arm engineer Kristof Beyls developed a static binary analyzer on BOLT, to assist with securing security-relevant code generation. With the help of Quarkslab and Sovereign Tech Agency, the BOLT scanner received custom security work to extend coverage of the scanner.
Engagement Process:
OSTIF engaged Quarkslab in early 2026 to expand the range of the BOLT binary scanner. It was up to the security engineers to analyze and identify which compiler flags and which areas could be actionably improved and to create scanners to target those areas that were accurate and effective. First, the team analyzed candidate compiler flags and potential areas for improved coverage. Once areas were identified and approved, Quarkslab moved into scanner design and implementation, ensuring that the work was practically effective on the project. Finally, the engagement was evaluated for impact and areas for future work were outlined in the report.
Engagement Results:
- Extended compiler coverage
- Custom scanner implemented
- Documentation
- Full compiler flag review: findings, architecture, flag adoption rates and functional assessment of compliers
- Raw data of coreutils used in engagement by Quarkslab
Thank you to the individuals and groups that made this engagement possible:
- LLVM Foundation maintainers and community, especially: Kristof Beyls
- Quarkslab, especially: Francesco Cagnin, Samuel Hangouët, Nicolas Surbayrole, and Pauline Sauder
- Sovereign Tech Agency
You can read the Audit Report HERE
Everyone around the world depends on open source software. If you’re interested in financially supporting this critical work, reach out to us.