TCP-group 1995
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Wild pointers
- To: karn@qualcomm.com (Phil Karn), Paul Traina <pst@cisco.com>
- Subject: Wild pointers
- From: bruce@pixar.com (Bruce Perens)
- Date: Tue, 24 Jan 95 17:09 PST
- Cc: nos-bbs@hydra.carleton.ca, tcp-group@ucsd.edu
> What we did was also poison the memory freed with 0x0d's so any deref
> would cause a fault and a crash right away.
If you happen to be running on Unix and don't have Purify, download
ftp.pixar.com:/pub/bruce/ElectricFence-2.0.5.tar.gz (a gzipped tar
archive). Electric Fence will detect references to freed memory and
malloc buffer overruns. It works by placing a special inaccessable
memory page at the end (or beginning) of each malloc() buffer, and it
can also use this trick to make freed memory inaccessable. Code that
touches one of these inaccessable pages gets a segmentation fault, and
your debugger will tell you the exact instruction that caused the
problem.
Thanks
Bruce Perens AB6YM
--
<a href="http://www.rahul.net/perens>Bruce Perens AB6YM</a>
Voice phone: 510-215-3502 Internet: Bruce@Pixar.com
Amateur Radio: Bruce@ab6ym.ampr.org ab6ym@n0ary.#nocal.ca.usa.noam