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To: Michael Hancock <michaelh@cet.co.jp>
cc: FreeBSD Hackers <Hackers@freebsd.org>
Subject: Re: kern_mib.c:int securelevel = -1; 
Date: Wed, 07 Aug 1996 15:55:29 -0400
From: James da Silva <jds@TracerTech.COM>
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 > It looks like the assignment of securelevel was put into kern_mib.c from
 > kern_sysctl.c.  This is ok I guess, but I'd like to have an option
 > INSECURE that we can turn off...
 > 
 > #ifdef INSECURE
 > int securelevel = -1
 > #else
 > int securelevel
 > #endif
 > 
 > Here's the a comment from <sys/systm.h> ...

By the way, the comment is wrong on one important point: the disposition of
this variable in bss vs data will be irrelevant to a cracker.  If the
kernel is not immutable, the variable can be patched either way.

I still haven't heard of someone actually investigating and documenting all
the things necessary to make securelevel real, as opposed to just giving
people a false sense of extra security.  EG, for starters you'd have to
make every file that is touched in single-user mode immutable, and delay
starting up all your net daemons until securelevel goes past 0.  I'm not
sure if that's all.

Jaime
...............................................................................
: jds@tracertech.com /   Tracer Technologies, Inc.   \ Stand on my shoulders, :
:   James da Silva  / Mass Storage Software Solutions \    not on my toes.    :