This is someone related to a major TPM pet peeve of mine: the TPM only really cares about global device state and has no concept that a device may be a multi-user system, have multiple processes with different security levels, have multiple tenants, etc.
For example, it really ought to be possible to seal a secret such that it can only be unsealed if PCRs have certain values (the usual TPM thing) and the requester of the unseal operation is tagged by the OS (software TCB) as having a certain identity. The latter part is entirely missing from the TPM spec. (The identity could be a hash of the process, just a UUID, or just about anything else as long as it was reasonably well associated with the process in question. Obviously there are subtleties here.)
If the TPM worked the way I wanted, an unprivileged process running alongside Chrome would be completely unable to use the TPM to pretend to be Chrome.
For example, it really ought to be possible to seal a secret such that it can only be unsealed if PCRs have certain values (the usual TPM thing) and the requester of the unseal operation is tagged by the OS (software TCB) as having a certain identity. The latter part is entirely missing from the TPM spec. (The identity could be a hash of the process, just a UUID, or just about anything else as long as it was reasonably well associated with the process in question. Obviously there are subtleties here.)
If the TPM worked the way I wanted, an unprivileged process running alongside Chrome would be completely unable to use the TPM to pretend to be Chrome.