[8570] in Athena Bugs
AIX 3.1 kernel/mount/umount
daemon@ATHENA.MIT.EDU (John Carr)
Tue Nov 12 02:19:30 1991
To: probe@Athena.MIT.EDU
Cc: bugs@Athena.MIT.EDU
Date: Tue, 12 Nov 91 02:19:34 EST
From: John Carr <jfc@Athena.MIT.EDU>
It is possible for an unprivileged user to crash an RS/6000 using
directory mounts:
% mkdir /tmp/x
% mount /tmp /tmp/x
% cd /tmp/x
% cd x
% umount /tmp/x
% pwd
% ls
The system hangs after the ls command; I don't know if it eventually
reboots. (I discovered this, by accident, on tardis. If tardis is still
down in the morning then it can be assumed the system never recovers.)
Comment: a self-referential path is something that is so obviously a
potential problem when allowing the equivalent of hard linked directories
that I never thought these commands would cause any harm because IBM must
have forseen this use. I was interested to see what error I would get when
I tried to unmount a directory that was still being used.
