TPM & disk crypto

On 10/5/06, Erik Tews <erikdebian.franken.de>
wrote:
> First, you need a system with tpm. I assume you are
running linux. Then
> you boot your linux-kernel and an initrd using the
trusted grub
> bootloader. Your bios will report the checksum of
trusted grub to the
> tpm before giving control to your grub bootloader. Your
grub bootloader
> will then report the checksum of your kernel and your
initrd to the tpm
> before giving control to them.

Awesome, that's incredibly useful information.
I had not heard of trusted grub.  Thanks!

> One thing you should know is, that a tpm can never find
out, if a
> software meets some specifications, like does not have
an buffer
> overflow or does not execute code from the network or
so. You just can
> check is has not been altered.

Of course.  However, you can sandbox x86 code efficiently:
http://www.usenix.org/events/sec06/tech
/mccamant/mccamant_html/index.html
-- 
Enhance your calm, fellow citizen; it's just ones and
zeroes.
Unix "guru" for rent or hire -><- http://www.li
ghtconsulting.com/~travis/
GPG fingerprint: 9D3F 395A DAC5 5CCC 9066  151D 0A6B 4098
0C55 1484

------------------------------------------------------------
---------
The Cryptography Mailing List
Unsubscribe by sending "unsubscribe cryptography"
to majordomometzdowd.com

There are a few more things to know about TPM (I've been
playing with
it recently, and the scars have not healed yet).

First, very few systems, mostly laptops, support it.  The
only
*server* platform I found that supports it is the IBM
eSeries 366, and
even then, its BIOS does not have support for it (hence, no
support
for authenticated booting (if you want to know the
difference between
*authenticated* and *secure* booting, it's explained in the
trusted-grub page).

Much of the software is still work-in-progress. 
Fortunately, the
people working on it are incredibly helpful.

The documentation of the spec is atrocious.  It's a 700-page
document
written in some vague approximation of English, with no
rhyme or reason
to its structure.

If you have more specific questions and don't want to bother
the whole
list, send me e-mail.

/ji

------------------------------------------------------------
---------
The Cryptography Mailing List
Unsubscribe by sending "unsubscribe cryptography"
to majordomometzdowd.com