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Date:      Wed, 8 May 2002 11:05:36 -0700
From:      Brooks Davis <brooks@one-eyed-alien.net>
To:        Miguel Mendez <flynn@energyhq.homeip.net>
Cc:        hackers@FreeBSD.ORG
Subject:   Re: extra sanity check in modules
Message-ID:  <20020508110535.A4025@Odin.AC.HMC.Edu>
In-Reply-To: <20020508171635.A50078@energyhq.homeip.net>; from flynn@energyhq.homeip.net on Wed, May 08, 2002 at 05:16:35PM %2B0200
References:  <20020508171635.A50078@energyhq.homeip.net>

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On Wed, May 08, 2002 at 05:16:35PM +0200, Miguel Mendez wrote:
> I've been thinking of adding an extra check in kldload. My idea is to hav=
e=20
> an md5 sum per module, so for foo.ko we'd have foo.ko.md5. At load time
> the md5 is checked, if it doesn't test ok the module is not loaded. The
> md5 files could chflagged as inmutable for extra security. Is it worth
> having this or just a silly idea? I might start hacking on my DP1 box on
> this thing later.

IMO, this is a silly idea, expecialy on a development version of the OS.
I always hated the schg flag on the kernel and I'm glad it's gone in
current.  I'd oppose adding that sort of foolishness to the modules.
It would make development of modules unnecessicairly painful.

Additional, I don't see any way this would prevent the loading of
unauthorized kernel modules since you could just create checksums
for them.  A better approach would probably be an integrity based MAC
solution which could refuse to load any module which arrived via an
untrusted medium (the network for example) or where created from sources
which did the same.  If I understand the TrustedBSD work, this may well
be possiable soon.

-- Brooks

--=20
Any statement of the form "X is the one, true Y" is FALSE.
PGP fingerprint 655D 519C 26A7 82E7 2529  9BF0 5D8E 8BE9 F238 1AD4

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