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Subject: Re: Security (was: Re: Two commands: icat and ils)
To: luigi@labinfo.iet.unipi.it (Luigi Rizzo)
Date: Mon, 22 Jan 1996 05:42:51 -0600 (CST)
From: "Mike Pritchard" <mpp@mpp.minn.net>
Cc: davidg@Root.COM, imp@village.org, hackers@freebsd.org,
        dworkin@rover.village.org
In-Reply-To: <199601221102.MAA04840@labinfo.iet.unipi.it> from "Luigi Rizzo" at Jan 22, 96 12:02:50 pm
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Luigi Rizzo wrote:
> > 
> >    That's not the reason they have read permissions removed. It's common for
> > people to have /sbin in their path - to pick up useful utilities which
> > probably shouldn't be in /sbin anyway (like ifconfig and ping, for example),
> > and executing /sbin/init by accident is not a good thing.
> 
> Two objections:
> 
> 1) just make /sbin/init mode 544 then. Actually, shouldn't it work
>    even if it has mode 444 ?
> 2) would it be that hard to fix init so as to quit if its not
>    appropriate for it to run (e.g. check process id, another instance
>    running, etc.) ? I am asking because I don't know what are the
>    implications, but if the consequences are so bad...

Actually, init already does this.  Here are the first few
lines of code from init.c:

	/* Dispose of random users. */
	if (getuid() != 0) {
		(void)fprintf(stderr, "init: %s\n", strerror(EPERM));
		exit (1);
	}

	/* System V users like to reexec init. */
	if (getpid() != 1) {
		(void)fprintf(stderr, "init: already running\n");
		exit (1);
	}
-- 
Mike Pritchard
mpp@minn.net
"Go that way.  Really fast.  If something gets in your way, turn"