Description: A vulnerbility exists in BSDi 4.0.1 Symmetric Multiprocessing (SMP). During high CPU usage it is possible to cause BSDi 4.0.1 (possibly others but untested) with all current patches to stop responding and 'lock up' when a call to fstat is made. Reproduction: This is very simple to reproduce. Simply run a few instances of commands which will eat up large amounts of CPU (top -s .1). When the CPU hits a reasonable amount, begin to run fstat. After the first 20-30 lines your machine should stop responding. Solution: At this time, after consulting BSDi, it has been determined that this issue has yet to be encountered. The following temporary fixes should be able to prevent this in the future until BSDi is able to release an official patch: 1.) Simply chmod 000 to /usr/bin/fstat 2.) Either move or remove /etc/mp.config. During boot, if this file is not found, BSDi will not boot into SMP mode. Credits: _THE MAN_ who ponted this out to me at work the other day (I'm not sure if you want people knowing your name, you know who you are). He was the one to discover that there was an issue with BSDi locking up when a call to fstat was made... I was only the one to verify this and discover that it was due to SMP (with the help of the tech from BSDi of course... (You know who you are too, thanks for your help). - Ben ***************************** * Ben Lull * * PSN Internet Services * * Jr. Systems Administrator * ***************************** - I may be a kid, but hey Mom, look at me now! - The only true type of freedom is that of speech (and a debugger).
This archive was generated by hypermail 2b30 : Fri Apr 13 2001 - 14:56:45 PDT