Path: utzoo!attcan!uunet!husc6!bloom-beacon!tut.cis.ohio-state.edu!mailrus!wasatch!utah-gr!uplherc!sp7040!obie!wsccs!terry
From: terry@wsccs.UUCP (Every system needs one)
Newsgroups: comp.unix.questions
Subject: Re: halt not by root
Summary: real vs. effective uid
Keywords: halt ! not root
Message-ID: <685@wsccs.UUCP>
Date: 28 Sep 88 05:36:10 GMT
References: <1128@usfvax2.EDU> <4051@polyslo.CalPoly.EDU>
Lines: 28

>>... how can I give halt(8) permission to users other than
>>root. We shut the system down at night ...
>	The real question is, do you NEED to shut this machine down every night?
>Is it such a power hog that you can't leave it running???

halt() checks real uid and gid.  Your suid root program only has the
right euid and egid.

How to get around it:

Fake it with two programs.  The other program just does a halt()... or
you could use the regular shell command for it.  Either way, it has to be
another program.


Tricking the halt command by faking your uid gid:

	system( "sh -c haltprogram");

Magic, eh?


| Terry Lambert           UUCP: ...{ decvax, ihnp4 } ...utah-cs!century!terry |
| @ Century Software        OR: ...utah-cs!uplherc!sp7040!obie!wsccs!terry    |
| SLC, Utah                                                                   |
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