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Kernel Level File Integrity Checker
Mentor
Student (+contact information)
Abstract
This project will focus on providing file integrity checking capabilities to pefs. The file integrity checker will compare cryptographic checksums of files against a static signed checksum list at access time. The files are thought to be immutable and use of securelevel will guarantee that lower filesystems will protect those files. Securelevel will be extended to only permit execution of files with immutable flag set.
Timeline
April 24 – May 20: Evaluate design choices with mentor and study pefs codebase.
May 21 - June 3: Extend sbin/pefs so that it creates checksum file with dummy tags/tweaks which is then read during pefs_mount. pf_nodes are properly marked upon creation.
June 4 - June 17: Extend sbin/pefs so that it accepts secret key from userland and that proper tags/tweaks are created for checksum file. At this point test with one HMAC algorithm.
June 18 – July 1: Integrity checks in Vnode Operations.
July 2 - July 12: Excessive testing of new features and review code with mentor. If there's enough time, add extra HMACs or even option for simple hash and test those as well.
July 13: Midterm Evaluations
July 14 - July 30: Implement authentication checks for checksum files during mount.
July 31 – August 13: Extension of securelevel and perhaps rtld.
August 13 - August 20: More testing, write documentation.
Final shipping to Google.
EOF
Feel free to share any thoughts!
Design/Test plan
The design, as described in my original gsoc proposal may be found in the attached pdf file. I've appended the technical comparison of my gsoc proposal and mac_chkexec to the end of the file.
Note
I'll try to keep a sort of developer's documentation using this wiki, updating it during the summer as relative features find their way into the source tree.
Source Code
References
- The Design and Implementation of the FreeBSD Operating System, by McKusick & Neville-Neil