On Sun, Sep 14, 2025 at 07:08:37PM +0300, Jarkko Sakkinen wrote: > Hi, > > In practice, while implementing tpm2sh and its self-contained TPM emulator > called "MockTPM", I've noticed that 'tpm2key.asn1.' has a major bottleneck, > but luckily it is easy to squash. > > Parent handle should never be persisted, as it defies the existential > reason of having a file format in the first place. > > To address this issue I just added couple of optional fields to TPMKey: > > parentName [6] EXPLICIT OCTET STRING OPTIONAL, > parentPubkey [7] EXPLICIT OCTET STRING OPTIONAL > > By persisting this information TPM2_GetCapability + TPM2_ReadPublic can > be used to acquire an appropriate handle. > > I'd highly recommend to add this quirk to anything that processes this > ASN.1 format.
Here's a proof of concept: https://github.com/puavo-org/tpm2sh/commit/18ec3c2169b23523d8866c58fa7b8a89a79bd3d4 BR, Jarkko
