Re: [Xen-devel] trusted computing

David Hopwood
Mon, 18 Oct 2004 23:16:43 -0000

Tim Freeman wrote:

> not about Xen in particular, but as a side note, because I think some
> people are interested in trusted computing and virtualization?  If
> you''re not, sorry for the intrusion!
>
> http://www.research.ibm.com/secure_systems_department/projects/tcglinux/
>
> "Currently, we experiment measuring the information flow on SELinux
> systems to reason about isolation properties of a system. For this
> purpose, we modified tcgLinux to run as an LSM kernel module stacked on
> top of SELinux. We also envision to extend our attestation method to
> integrate virtualization technology and partition the attestation space
> of a system using the information flow policies enforced therein."

# [tcgLinux]''s main goal is to generate verifiable representative
information
# about the software stack running on a Linux system. This information can
# be used by remote parties to determine the integrity of the execution
# environment.

Can it, though? The assumption seems to be that fingerprinting executables
is sufficient to characterise the security configuration of a system.
AFAICS that''s patently false: the security of a system is dependent on
its
complete configuration, including many non-executable files. IOW, anyone
can compromise a system without changing any executable files.

# We instrumented the Linux kernel to trigger a measurement for each
# executable, library, or kernel module loaded into the run-time before
# they affect the system.

Yep, only executables. This seems quite useless.

--
David Hopwood <david.nospam.hopwood@blueyonder.co.uk>