Change the low-level Quote() functions so that the PCRs to be
included in the quote is selectable. Does not change the
high-level attestPlatform functions, which still retrieve
all PCRs.
The change is a no-op for existing clients, and it will simplify
adding the support for ECC EKs. The activation code no longer makes
assumptions about EK's type and handle (i.e. RSA and 0x81010001),
and instead relies on TPM.EKs() to provide the EK's details.
Fixes: issues/320.
Adds support for generating an activation challenge using
CertificationParameters.
Achieves symmetry with challenge-generation in
AttestationParameters, in order to provide a challenge to a
TPM to activate a TPM-certified key.
`attest.Activation` currently supports verifying and
generating a challenge given attestationData, an EK, an AK,
and a signature. In the attestationData, the CreationInfo
field is used to further validate and create the resulting
challenge.
In this change, `attest.Certification` will now support
generating a challenge given attestationData, an EK, a
TPM-certified public key, and a signature, in addition to
an AK used to verify the certification of the provided
public key we are generating an activation challenge for.
* Fix Intel EK certificate URL
To download the certificate for an Intel TPM, the base64 padding
in the URL needs to be replaced with `%3D`. If it's not replaced,
requesting the URL will result in HTTP 403 Forbidden.
* Use `url.QueryEscape` to escape base64 padding
This is the same approach tpm2_getekcertificate uses, with its
`TPM2_HANDLE_FLAGS_NV` flag.
The main impetus here is is ChromeOS's vtpm implementation[1], which
doesn't have a concept of an "owner" or "platform" password and expects
the NV index itself as the auth hierarchy. In either case, as this is
the same approach tpm2_getekcertificate uses this should provide a more
standard/common approach as opposed to relying on the owner password to
be empty.
Tested with both CrOS's vTPM and a real TPM on Debian.
b/258300352
[1]: https://source.chromium.org/chromiumos/chromiumos/codesearch/+/main:src/platform2/vtpm/commands/nv_read_command.cc;l=64-68;drc=1efd0c8f36050d56b8550354a4c7af925e44118a
In `wrappedTPM20.getPrimaryKeyHandle()`, preserve any error from the
short-circuit `tpm2.ReadPublic()` logic, so that we can return it
alongside any failure in `tpm2.CreatePrimary()`
Co-authored-by: Justin King-Lacroix <justinkl@google.com>
The specific error type is not part of x509.ParseCertificate documented
API. So we shouldn't rely on it for this workaround.
Signed-off-by: Joe Richey <joerichey@google.com>
* AKPublic.Verify: Return an error if a provided PCR of the correct
digest was not included in the quote.
* AKPublic.VerifyAll: Implement VerifyAll method, which can cross-check
that provided PCRs were covered by quotes across PCR banks.
* PCR.QuoteVerified(): Introduce getter method to expose whether a
PCR value was covered during quote verification.
This change allows users to specify TPM1.2 support rather than remove it.
go-attestation will build without needing Trousers/TSPI support.
The flip-side of this is that TPM1.2 does not just work; TPM1.2 users need to
include the `tspi` build tag.
