Date: Thu, 11 Mar 1999 19:30:29 -0500 (EST) From: Robert Watson <robert@cyrus.watson.org> To: Mark Newton <newton@camtech.com.au> Cc: Archie Cobbs <archie@whistle.com>, ark@eltex.ru, freebsd-security@FreeBSD.ORG Subject: Re: FreeBSD SKIP port updated Message-ID: <Pine.BSF.3.96.990311192831.6494F-100000@fledge.watson.org> In-Reply-To: <199903120019.KAA05025@frenzy.ct>
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On Fri, 12 Mar 1999, Mark Newton wrote:
> Archie Cobbs wrote:
>
> > Mark Newton writes:
> > > > > I am curious if someone tried to update it to compile in-kernel.
> > > > > I don't use LKMs, i have them disabled for security reasons (no flames
> > > > > please)
> > > >
> > > > Well, there's no reason you couldn't load it at boot time.
> > > > Ie, add it to boot.conf (or loader.conf of whatever it's called).
> > >
> > > If you have KLDs disabled that shouldn't work (and it represents a
> > > pretty major security issue if it does!)
> >
> > I thought the disabling of KLD's only blocked the kldload() process.
> > Guess not.
>
> From a brief look at the source, you might be right.
>
> This is bad. I'd think disabling KLDs should totally disable the
> in-kernel linker. Otherwise someone could get new modules into your
> kernel by adding 'em to loader.rc and forcing a reboot.
Arguably, in a securelevel environment, the {/boot,/modules} directories
should be entirely noschg. Otherwise the user could specify alternative
kernels, use alternative bootstrap code, etc. Any of these yields kernel
privileges.
I would argue that disabling kldload in securelevels is a good idea;
removing the ability to have a dynamically linked kernel from /modules et
al is a bad idea; instead, appropriate file protection should be used.
Robert N Watson
robert@fledge.watson.org http://www.watson.org/~robert/
PGP key fingerprint: 03 01 DD 8E 15 67 48 73 25 6D 10 FC EC 68 C1 1C
Carnegie Mellon University http://www.cmu.edu/
TIS Labs at Network Associates, Inc. http://www.tis.com/
Safeport Network Services http://www.safeport.com/
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