On Wed, Sep 11, 2019 at 09:42:49AM +0100, Jarkko Sakkinen wrote: > On Tue, Sep 10, 2019 at 05:21:32PM +0100, Jarkko Sakkinen wrote: > > On Mon, Sep 09, 2019 at 01:16:48PM +0100, James Bottomley wrote: > > > Link to previous cover letter: > > > > > > https://lore.kernel.org/linux-integrity/1540193596.3202.7.camel@xxxxxxxxxxxxxxxxxxxxx/ > > > > > > This is marked v6 instead of v5 because I did a v5 after feedback on v4 > > > but didn't get around to posting it and then had to rework the whole of > > > the kernel space handling while I was on holiday. I also added the > > > documentation of how the whole thing works and the rationale for doing > > > it in tpm-security.rst (patch 11). The main reason for doing this now > > > is so we have something to discuss at Plumbers. > > > > > > The new patch set implements the various splits requested, but the main > > > changes are that the kernel space is gone and is replaced by a context > > > save and restore of the generated null seed. This is easier to handle > > > than a full kernel space given the new threading for TPM spaces, but > > > conceptually it is still very like a space. I've also made whether > > > integrity and encryption is turned on a Kconfig option. > > > > > > James > > > > So... is there a changelog for the revisions? > > This also desperately needs a cover letter with the full rationale and > not just a link to an aged cover letter. I have bigger problems with the > form than the function ATM. > > TPM's threat model does not cover hardware attacks. It is hardware > designed to give some protection against software attacks. If I were > sending these patches I would start to look for an angle from that > perspective. The rationale can be essentially just that since there is often lots of *software* running outside the CPU on different cores all around the HW platform, this will add to defense in depth. I'm not looking for anything more rockety sciency than that. I think that was the key lesson from TPM Genie. /Jarkko
