This subproject´s target is the specification, implementation, (partially) verification and automated testing of ACL (access control list) support for the ext2 filesystem. For a somewhat longer discussion of ACL see a Digital Unix man page .

When we checked for work already in progress, we found that there was already work done on ACL support by Remy Card, the maintainer of the ext2 file system. We started from his patch to linux 2.1.99. There exist also some slides from Remy Card et al. about the ext2 and especially ACL support at tsx-11.

We reworked Remy Card's code and inserted the ACL support in linux 2.2.0-pre9 and later in linux 2.2.3. We also made it compliant to POSIX 1003.6 draft 17. Then we started to setup a test suite using RT tester from Verified Systems and ASpecT. We tested the correct result of getting / setting the ACL of files and directories. While testing it we found another pile of bugs. Up to now we fired some hundred thousands tests against our implementation. The last 60.000 tests did not show up errors any more. There is also work going on at http://acl.bestbits.at/

Click here to download patches and utilities.

Papers (german)

• We have used Z for the formal specification. It is not finished yet, but the core functions are specified. postscript.
• Some general papers about verification:
  • Some sliders.postscript.
  • The discussion.postscript.
  Sorry, no HTML version: Latex2Html couldn´t get the formulas.

• VFS + ext2fs. postscript
• VFS + ext2fs. postscript
• ACL description. postscript

The subproject members

• Hauke Steenbock
• Matthias Riese.