* Use application/pem-certificate-chain for PEMs
As mentioned in #10948, it appears we're incorrectly using the
`application/pkix-cert` media type for PEM blobs, when
`application/x-pem-file` is more appropriate. Per RFC 5280 Section
4.2.1.13, `application/pkix-crl` is only appropriate when the CRL is in
DER form. Likewise, Section 4.2.2.1 states that `application/pkix-cert`
is only applicable when a single DER certificate is used.
Per recommendation in RFC 8555 ("ACME"), Section 7.4.2 and 9.1, we use
the newer `application/pem-certificate-chain` media type for
certificates. However, this is not applicable for CRLs, so we use fall
back to `application/x-pem-file` for these. Notably, no official IETF
source is present for the latter. On the OpenSSL PKI tutorial
(https://pki-tutorial.readthedocs.io/en/latest/mime.html), this type is
cited as coming from S/MIME's predecessor, PEM, but neither of the main
PEM RFCs (RFC 934, 1421, 1422, 1423, or 1424) mention this type.
Signed-off-by: Alexander Scheel <alex.scheel@hashicorp.com>
* Add changelog entry
Signed-off-by: Alexander Scheel <alex.scheel@hashicorp.com>
Alexander Scheel