[4853] in Athena Bugs
csh man page again, shutdown
daemon@ATHENA.MIT.EDU (Joe Harrington)
Tue May 1 16:55:38 1990
Date: Tue, 1 May 90 16:53:33 -0400
From: Joe Harrington <jh@ATHENA.MIT.EDU>
To: jik@pit-manager.MIT.EDU
Cc: bugs@ATHENA.MIT.EDU
In-Reply-To: "Jonathan I. Kamens"'s message of Tue, 1 May 90 16:36:07 -0400 <9005012036.AA16764@pit-manager.MIT.EDU>
Cc: jh@ATHENA.MIT.EDU
Reply-To: jh@ATHENA.MIT.EDU
try running shutdown from a set-uid root (borne) shell script on a
machine set up to do nfs service. shutdown attempts to send a
zephyrgram to the operations instance saying that the machine is going
down and please detach filesystems. the zgram sent looks suspiciously
like that sent by zwrite -f machine-name. if the shutdown program is
run by a user from inside a setuid root (borne shell) script, the
zgram does not get sent;
instead, the message
csh: permission denied
appears. this is suspiciously similar to the
csh: permission denied
message that occurs if you try to run a setuid root csh script.
without looking at the source, i'm guessing that somewhere in the
process of sending the zgram, a csh is forked, notices that uid and
euid don't match, and freaks out. it would seem to me that forking
shells from the shutdown program is unnecessary.
re: csh man page
i grepped for setuid and uid. a basic behavior like that ought to be
more clearly documented in a man page that large (or you get "bug"
reports like mine :-).
--jh--
