On Mon, 2024-02-05 at 15:27 +0800, Gary Lin via Grub-devel wrote: > On Wed, Jan 17, 2024 at 04:13:17PM +0800, Gary Lin wrote: > > On Tue, Jan 16, 2024 at 10:39:45AM -0500, James Bottomley wrote: > > > On Tue, 2024-01-16 at 17:20 +0800, Gary Lin via Grub-devel wrote: > > > [...] > > > > (*1) > > > > https://www.hansenpartnership.com/draft-bottomley-tpm2-keys.html > > > > (*2) https://github.com/okirch/pcr-oracle > > > > > > Just a curiosity question, but have you tested the > > > interoperability of > > > pcr-oracle keys? It looks like you got the ASN header straight > > > from > > > openssl_tpm2_engine, so it should all just work, but verifying > > > that the > > > seal/unseal and sign_tpm2_policy commands from > > > openssl_tpm2_engine: > > > > > > https://build.opensuse.org/package/show/security:tls/openssl_tpm2_engine > > > > > > can be used to create sealed keys for this code would nicely > > > verify > > > that. > > > > > I have to admit that the interoperability is not considered since > > the > > sealed key is designed to be only valid in a short window and > > capped > > after load linux kernel. However, it'd be nice to verify the format > > with > > other programs like openssl_tpm2_engine. > > > > My playground of grub2 is an openSUSE Tumbleweed VM and > > openssl_tpm2_engine is available. Will check if the key file from > > pcr-oracle works for openssl_tpm2_engine. > > > I did quick check, and the major difference between pcr-oracle and > openssl_tpm2_engine is the assumption of SRK. pcr-oracle choose RSA > 2048 or above for the SRK template while openssl_tpm2_engine assumes > ECC to be used as SRK,
Right that's because the standard says you have to (in section 3.1.6): If a permanent handle (MSO 0x40) is specified then the implementation MUST run TPM2_CreatePrimary on the handle using the TCG specified Elliptic Curve template [TCG-Provision] (section 7.5.1 for the Storage and other seeds or 7.4.1 for the endorsement seed) for the NIST P-256 curve and use the primary key so generated as the parent. It was for two reasons: 1) so we all derive the same parent for interoperability and 2) because some TPMs take forever to derive an RSA primary (my current one takes 7s and my previous one took 50s) > and openssl_tpm2_engine failed to unseal the key file > created by pcr-oracle. Anyway, at least 'signed_tpm2_policy' can list > the signed polices in the key. Bus is there a reason we shouldn't be fully interoperable? James _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel
