Path: utzoo!utgpu!cunews!bnrgate!brtph3!brchh104!brchs1!bnr.ca!rice.edu!sun-spots-request
From: think!barmar@bloom-beacon.mit.edu (Barry Margolin)
Newsgroups: comp.sys.sun
Subject: Re: Execute permissions on /usr/etc/halt
Keywords: Miscellaneous
Message-ID: <509@brchh104.bnr.ca>
Date: 28 Nov 90 17:45:45 GMT
Sender: news@brchh104.bnr.ca
Organization: Sun-Spots
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Approved: Sun-Spots@rice.edu
X-Original-Date: Wed, 21 Nov 90 01:45:46 GMT
X-Refs:  Original: v9n371
X-Sun-Spots-Digest: Volume 9, Issue 380, message 7
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In article <356@brchh104.bnr.ca> patrick@casbs.stanford.edu (Patrick Goebel) writes:
>On our 4/330 running SunOS 4.0.3 I find:
>
>% ls -lFg /usr/etc/halt
>-rwxr-xr-x  1 root     staff       81920 Apr 24  1989 halt*
>
>Don't these permissions imply that any mortal user could halt the system?!

No.  The halt program has to perform a system call to actually reboot the
system, and this system call is restricted to the superuser (otherwise any
user could write their own halt program).

It would be a problem if /usr/etc/halt were *setuid* to root, e.g. if the
permission were -rwsr-xr-x.

Barry Margolin, Thinking Machines Corp.

barmar@think.com
{uunet,harvard}!think!barmar