On Thu, 2024-05-23 at 16:19 +0300, Jarkko Sakkinen wrote: > There's no reason to encode OID_TPMSealedData at run-time, as it > never changes. > > Replace it with the encoded version, which has exactly the same size: > > 67 81 05 0A 01 05 > > Include OBJECT IDENTIFIER (0x06) tag and length as the epilogue so > that the OID can be simply copied to the blob.
This is true, but if we're going to do this, we should expand the OID registry functions (in lib/oid_registry.c) to do something like encode_OID. The registry already contains the hex above minus the two prefixes (which are easy to add). I also note: > @ -51,8 +52,8 @@ static int tpm2_key_encode(struct > trusted_key_payload *payload, > if (!scratch) > return -ENOMEM; > > - work = asn1_encode_oid(work, end_work, tpm2key_oid, > - asn1_oid_len(tpm2key_oid)); > + work = memcpy(work, OID_TPMSealedData_ASN1, > sizeof(OID_TPMSealedData_ASN1)); > + work += sizeof(OID_TPMSealedData_ASN1); You lost the actually fits check. This is somewhat irrelevant for TPM keys because the OID is first in the structure and thus will never overflow, but it might matter for other uses. James
