Re: Symlink problem (Tested only on a Digital Unix 4.0)

From: Paul Szabo (pszat_private)
Date: Mon Apr 06 1998 - 16:17:56 PDT

  • Next message: John McDonald: "Re: Symlink problem (Tested only on a Digital Unix 4.0)"

    (Aleph1 and rusty: please ignore my previous, similar message...)
    
    rustyat_private 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
    pszat_private         //   University of Sydney, NSW 2006, Australia
    



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