rusty@mad.it wrote:
> Symlink problem in Digital Unix 4.0 ...
> Starting 2 suid root programs ... and killing them with -11 flag ...
> $ ln -s /.rhosts core
> $ ping somehost &
> [1] 1337
> $ ping somehost &
> [2] 31337
> $ kill -11 31337
> $ kill -11 1337
> [1] Segmentation fault /usr/sbin/ping somehost (core dumped)
> [2] +Segmentation fault /usr/sbin/ping somehost (core dumped)
> $ ls -l /.rhosts
> -rw------- 1 root system 385024 Mar 29 05:17 /.rhosts
>
> Other platforms:
>
> SunOs 4.1.x 5.5.x Doesn't work
> Linux 2.0.x Doesn't work
> Digital Unix 4.0d Doesn't work
> Others (note tested yet)
I can reproduce this on Digital Unix 4.0B (OSF1 V4.0 564), with just one
setuid program:
% unsetenv DISPLAY; xterm
The only defence I can offer is to put the following line into the file
/sbin/rc3 (this is a sh script; most processes run by users are descendants
of this):
ulimit -h -c 0
However this does not work for processes started from /etc/inittab: getty
(console and tty) logins. Instead of modifying /sbin/rc3, you could try
changing /etc/inittab to read something like:
s3:3:wait:sh -c 'ulimit -h -c 0; /sbin/rc3 < /dev/console > /dev/console 2>&1'
cons:1234:respawn:sh -c 'ulimit -h -c 0; /usr/sbin/getty console console vt100'
Obviously this prevents creating core files in all cases; fortunately our
users never need them to debug their own programs.
Paul Szabo - System Manager // School of Mathematics and Statistics
psz@maths.usyd.edu.au // University of Sydney, NSW 2006, Australia