rsa pki encoding/decoding tests and fix for encoding rsapss to pki

[sebastian-carpenter]

This mainly contains testing for encoding / decoding RSA and RSASSA-PSS keys to / from pki.

Found some bugs and fixed them:

• RSASSA-PSS key params are not encoded to DER when using pki encoding. Copied some code from the spki encoding section for a fix (altered it slightly for different offsets).
• WolfProvider returns digest names that do not match those of OSSL. Made a mapping function based on a wolfcrypt enum.

Addendum:

• When doing the encoding test the created der was then decoded with ossl and wp. Changed test_rsa_decode_pkcs8_evp_pkey to allow decoding ctx to be specified. Now decoding can be done with ossl and wp, or just ossl.

[SparkiDev]

Why does wp_rsa_import have a parameter with a string that is the wrong name form?
We have places we set mdName to something explicitly and they can be changed but the import should be the same as

[SparkiDev]

Initialise these four pointer.

[sebastian-carpenter]

Now initialized to NULL

[SparkiDev]

Missing SHA512-224 and SHA512-256

[sebastian-carpenter]

Added both types and several others. Wrapped new additions in ifdef's

[SparkiDev]

Initialise to NULL.

[sebastian-carpenter]

Initalized to NULL and changed name to osslDigest

[sebastian-carpenter]

Why does wp_rsa_import have a parameter with a string that is the wrong name form? We have places we set mdName to something explicitly and they can be changed but the import should be the same as

comment seems cut off so I took my best guess. I didn't do anything to wp_rsa_import so I'm thinking this is meant to refer to wp_digest_to_ossl_digest. Previously the parameter was ossl_digest so I changed it to osslDigest in the rebase.

As for why this functions exists: When you get parameters from wolfProvider the md and mgf should match what OpenSSL uses for their digest names. I didn't edit what the md and mgf were set to in wolfProvider since it seems like that could cause issues in wolfCrypt (though I'm not certain).