Yesterday I gave a presentation at OSDC in Melbourne about my Postal mail server benchmark suite. The paper was about my new benchmark program BHM for testing the performance of mail relay systems and some of the things I learned by running it. I will put the paper on my Postal site in the near future and also I’ll release a new version of Postal with the code in question very soon.

Today at OSDC I gave a 5 minute talk on 5 things that need to be improved in the security of Linux distributions.

  1. The fact that unprivileged programs often inherit the controlling tty of privileged programs which permits them to use the TIOCSTI ioctl to insert characters in the keyboard buffer. I noted that with runuser and a subtle change to su things have been significantly improved in this regard in Fedora, but other distributions need work (and Fedora can go further in this regard).
  2. A polyinstantiated /tmp should be an option that is easy to configure for a novice sys-admin. There have been too many attacks on data confidentiality and system integrity based on file name race conditions in /tmp, this needs to be fixed and must be fixable by novice sys-admins.
  3. The capability system needs to be extended. 31 capabilities is not enough and the significant number of operations that are permitted by CAP_SYS_ADMIN leads to granting excessive privilege to programs.
  4. The use of Xen on servers such that a domU is always used for applications should become common. Then if a compromise is suspected there will be better options for investigation.
  5. SE Linux needs to be used more, particularly the strict policy and MCS. Use of the strict policy often reveals security flaws in other programs.

I’ll blog about each of these in detail at some future time.

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