Allow setting OSSL_PKEY_PARAM_ENCODED_PUBLIC_KEY for EC keys

[manison]

This PR implements set_params method for EC keys that allows assigning OSSL_PKEY_PARAM_ENCODED_PUBLIC_KEY parameter. This parameter is required for EVP_PKEY_set1_encoded_public_key to function properly. This function is in turn used by CMS_decrypt_set1_pkey_and_peer so without this decrypting a CMS does not work at all.

This PR also adds a test to check CMS encrypt/decrypt using an EC key. Since decrypting a CMS uses CKM_ECDH1_DERIVE mechanism with shared data the test is being run on nss-softokn only. Although SoftHSM2 also supports ECDH1 derivation mechanism it currently (softhsm/SoftHSMv2#599) only does when no shared data is specified.

[simo5]

@manison this looks interesting.
I am surprised that the code expects public key data to already exist and be replaced.
How is the API actually work here?
What's in the key public attributes before the setting happens?

[manison]

It's during CMS_Decrypt, it should be easily visible from the tcms test I added in this PR.

This is the backtrace:

pkcs11.dll!p11prov_obj_set_ec_encoded_public_key(p11prov_obj * key, const void * pubkey, unsigned __int64 pubkey_len)
pkcs11.dll!p11prov_ec_set_params(void * keydata, const ossl_param_st * params)
[Inline Frame] libcrypto3.dll!EVP_PKEY_set_params(evp_pkey_st *)
[Inline Frame] libcrypto3.dll!EVP_PKEY_set_octet_string_param(evp_pkey_st *)
libcrypto3.dll!EVP_PKEY_set1_encoded_public_key(evp_pkey_st * pkey, const unsigned char * pub, unsigned __int64 publen)
libcrypto3.dll!ecdh_cms_set_peerkey(evp_pkey_ctx_st * pubkey, X509_algor_st *)
libcrypto3.dll!ecdh_cms_decrypt(CMS_RecipientInfo_st * ri)
libcrypto3.dll!CMS_RecipientInfo_kari_decrypt(CMS_ContentInfo_st * cms, CMS_RecipientInfo_st * ri, CMS_RecipientEncryptedKey_st * rek)
[Inline Frame] libcrypto3.dll!cms_kari_set1_pkey_and_peer(CMS_ContentInfo_st *)
libcrypto3.dll!CMS_decrypt_set1_pkey_and_peer(CMS_ContentInfo_st * cms, evp_pkey_st * pk, x509_st * cert, x509_st * peer)
[Inline Frame] libcrypto3.dll!CMS_decrypt_set1_pkey(CMS_ContentInfo_st *)
libcrypto3.dll!CMS_decrypt(CMS_ContentInfo_st * cms, evp_pkey_st * pk, x509_st * cert, bio_st * dcont, bio_st * out, unsigned int flags)

The ecdh_cms_set_peerkey calls EVP_PKEY_copy_parameters so my guess is that they duplicate a key and then replace its public part?

[simo5]

Ok, I see how this is messed up, but it is what it is.
What I need here before we can merge is a check that will refuse to set parameters if this is a key from the token. Parameter setting should be available only for generated keys.
We may need to add a boolean to the key structure to record this fact.

[manison]

What I need here before we can merge is a check that will refuse to set parameters if this is a key from the token. Parameter setting should be available only for generated keys.

Agreed.

We may need to add a boolean to the key structure to record this fact.

Wouldn't it be enough to check the object handle and/or slot id?

[simo5]

Wouldn't it be enough to check the object handle and/or slot id?

I guess that will work, yeah.

[manison]

I added the check to verify we only set public key to mock objects.

[simo5]

Looks good

[simo5]

Sadly we have some CI woes lately, but this looks good, so I'll merge and fix CI later.