As with SPKI parsers, the intent is make EVP_PKEY capture the key's
constraints in full fidelity, so we'd have to add new types or store the
information in the underlying key object if people introduce variant key
types with weird constraints on them.
Note that because PKCS#8 has a space for arbitrary attributes, this
parser must admit a hole. I'm assuming for now that we don't need an API
that enforces no attributes and just ignore trailing data in the
structure for simplicity.
BUG=499653
Change-Id: I6fc641355e87136c7220f5d7693566d1144a68e8
Reviewed-on: https://boringssl-review.googlesource.com/6866
Reviewed-by: Adam Langley <agl@google.com>
e30a09e604