From: "Daniel P. Smith" <email@example.com> To: Matthew Garrett <firstname.lastname@example.org> Cc: Ross Philipson <email@example.com>, Linux Kernel Mailing List <firstname.lastname@example.org>, the arch/x86 maintainers <email@example.com>, firstname.lastname@example.org, Thomas Gleixner <email@example.com>, Ingo Molnar <firstname.lastname@example.org>, Borislav Petkov <email@example.com>, "H. Peter Anvin" <firstname.lastname@example.org>, email@example.com Subject: Re: [RFC PATCH 00/12] x86: Trenchboot secure late launch Linux kernel support Date: Thu, 26 Mar 2020 18:37:20 -0400 Message-ID: <firstname.lastname@example.org> (raw) In-Reply-To: <CACdnJusRATYv3Une5r14KHJVEg5COVW9B_BNViUXjavSxZ6d5A@mail.gmail.com> On 3/26/20 4:54 PM, Matthew Garrett wrote: > On Thu, Mar 26, 2020 at 1:50 PM Daniel P. Smith > <email@example.com> wrote: >> It is not part of the EFI entry point as we are not entering the kernel >> from EFI but I will address that further in my response to Andy. The >> expectation is that if you are on an UEFI platform then EBS should have >> already been called. > > Ok. In that case should the EFI boot stub optionally be calling this > instead of startup_32? > >> With respect to using the firmware's TPM code, one >> of the purposes of a TCG Dynamic Launch is to remove the firmware from >> the code being trusted in making the integrity measurement of the >> kernel. I trust the firmware to initialize the hardware because I have >> to and it does give a trust chain, aka the SRTM, that can attest to what >> was used during that process. When the OS kernel is being started that >> trust chain has become weak (or even broken). I want a new trust chain >> that can provide better footing for asserting the integrity of the >> kernel and this is what Dynamic Launch gives us. I would like to think I >> did a fair job explaining this at LSS last fall and would >> recommend those that are curious to review the slides/watch the >> presentation. > > PCs depend on the availability of EFI runtime services - it's not > possible to just assert that they're untrusted and so unsupported. The > TPM code is part of boot services which (based on your design) are > unavailable at this point, so I agree that you need your own > implementation. > I appreciate this has been a heated area of debate, but with all due respect that might be a slight over statement w.r.t. dependency on runtime services and not what I was saying about the trustworthiness of UEFI. If I have a UEFI platform, I trust EFI to boot the system but that does not mean I have to trust it to measure my OS kernel or manage the running system. Secure Launch provides a means to start a measurement trust chain starting with CPU taking the first measurement and then I can do things like disabling runtime services in the kernel or do crazy things like using the dynamic launch to switch to a minimal temporary kernel that can do high trust operations such as interfacing with entities outside your trust boundary, e.g. runtime services. Please understand I really do not want my own implementation. I tried to see if we could just #include in the minimal needed parts from the in-tree TPM driver but could not find a clean way to do so. Perhaps there might be a future opportunity to collaborate with the TPM driver maintainers to refactor in a way that we can just reuse instead of reimplement.
next prev parent reply index Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-03-25 19:43 Ross Philipson 2020-03-25 19:43 ` [RFC PATCH 01/12] x86: Secure Launch Kconfig Ross Philipson 2020-03-26 18:06 ` Daniel Kiper 2020-03-26 19:42 ` Ross Philipson 2020-03-25 19:43 ` [RFC PATCH 02/12] x86: Secure Launch main header file Ross Philipson 2020-03-26 19:00 ` Daniel Kiper 2020-03-25 19:43 ` [RFC PATCH 03/12] x86: Add early SHA support for Secure Launch early measurements Ross Philipson 2020-03-26 3:44 ` Andy Lutomirski 2020-03-26 22:49 ` Daniel P. Smith 2020-03-25 19:43 ` [RFC PATCH 04/12] x86: Add early TPM TIS/CRB interface support for Secure Launch Ross Philipson 2020-03-25 19:43 ` [RFC PATCH 05/12] x86: Add early TPM1.2/TPM2.0 " Ross Philipson 2020-03-25 19:43 ` [RFC PATCH 06/12] x86: Add early general TPM " Ross Philipson 2020-03-25 19:43 ` [RFC PATCH 07/12] x86: Secure Launch kernel early boot stub Ross Philipson 2020-03-25 19:43 ` [RFC PATCH 08/12] x86: Secure Launch kernel late " Ross Philipson 2020-03-25 19:43 ` [RFC PATCH 09/12] x86: Secure Launch SMP bringup support Ross Philipson 2020-03-25 19:43 ` [RFC PATCH 10/12] x86: Secure Launch adding event log securityfs Ross Philipson 2020-03-25 20:21 ` Matthew Garrett 2020-03-25 21:43 ` Daniel P. Smith 2020-03-25 19:43 ` [RFC PATCH 11/12] kexec: Secure Launch kexec SEXIT support Ross Philipson 2020-03-25 19:43 ` [RFC PATCH 12/12] tpm: Allow locality 2 to be set when initializing the TPM for Secure Launch Ross Philipson 2020-03-25 20:29 ` [RFC PATCH 00/12] x86: Trenchboot secure late launch Linux kernel support Matthew Garrett 2020-03-25 22:51 ` Andy Lutomirski 2020-03-26 20:50 ` Daniel P. Smith 2020-03-26 23:13 ` Andy Lutomirski 2020-03-26 13:40 ` Daniel Kiper 2020-03-26 20:19 ` Matthew Garrett 2020-03-26 20:33 ` Andy Lutomirski 2020-03-26 20:40 ` Matthew Garrett 2020-03-26 20:59 ` Daniel P. Smith 2020-03-26 21:07 ` Andy Lutomirski 2020-03-26 21:28 ` Matthew Garrett 2020-03-26 22:52 ` Andy Lutomirski 2020-03-26 22:59 ` Matthew Garrett 2020-03-26 23:04 ` Andy Lutomirski 2020-03-27 0:01 ` Daniel P. Smith 2020-03-26 23:50 ` Daniel P. Smith 2020-03-26 20:50 ` Daniel P. Smith 2020-03-26 20:54 ` Matthew Garrett 2020-03-26 22:37 ` Daniel P. Smith [this message] 2020-03-26 22:41 ` Matthew Garrett 2020-03-26 23:55 ` Daniel P. Smith
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