Dear Pavel, > ... can you see a way to write to that file when /proc is unmounted? While there is legitimate access to do so (after file is created and before pavel issues 'chmod 700 /tmp/my_priv'), guest to use commands: ln /tmp/my_priv/unwritable_file /tmp/hardlink-to-object and then use that instead of /proc/self/fd/3, should work same as original "attack" (and am curious whether 'link counts' shown by 'ls -l /tmp/my_priv/unwritable_file' are 1 or 2 in each case). Cheers, Paul Paul Szabo psz@xxxxxxxxxxxxxxxxx http://www.maths.usyd.edu.au/u/psz/ School of Mathematics and Statistics University of Sydney Australia
