Add some documentation about the EVP_PKEY MAC interface

Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/12637)

3 files changed, 140 insertions, 4 deletions

diff --git a/doc/man3/EVP_PKEY_new.pod b/doc/man3/EVP_PKEY_new.pod
index c008cfff40..0543600704 100644
--- a/doc/man3/EVP_PKEY_new.pod
+++ b/doc/man3/EVP_PKEY_new.pod
@@ -104,9 +104,9 @@ EVP_PKEY_new_raw_private_key() except it is only for the B<EVP_PKEY_CMAC>
 algorithm type. In addition to the raw private key data, it also takes a cipher
 algorithm to be used during creation of a CMAC in the I<cipher> argument. The
 cipher should be a standard encryption only cipher. For example AEAD and XTS
-ciphers should not be used. Finally it also take a library context I<libctx>
-and property query I<propq> used when fetching any cryptographic algorithms
-which may be NULL to use the default values.
+ciphers should not be used. Finally it also takes a library context I<libctx>
+and property query I<propq> which are used when fetching any cryptographic
+algorithms which may be NULL to use the default values.
 
 EVP_PKEY_new_CMAC_key() is the same as EVP_PKEY_new_CMAC_key_with_libctx()
 except that the default values are used for I<libctx> and I<propq>.
@@ -172,7 +172,7 @@ EVP_PKEY_get_raw_public_key() functions were added in OpenSSL 1.1.1.
 
 The EVP_PKEY_new_raw_private_key_with_libctx(),
 EVP_PKEY_new_raw_public_key_with_libctx() and
-EVP_PKEY_new_CMAC_key_with_libctx()functions were added in OpenSSL 3.0.
+EVP_PKEY_new_CMAC_key_with_libctx() functions were added in OpenSSL 3.0.
 
 =head1 COPYRIGHT
 
diff --git a/doc/man7/EVP_PKEY-HMAC.pod b/doc/man7/EVP_PKEY-HMAC.pod
new file mode 100644
index 0000000000..7b6c52bb03
--- /dev/null
+++ b/doc/man7/EVP_PKEY-HMAC.pod
@@ -0,0 +1,95 @@
+=pod
+
+=head1 NAME
+
+EVP_PKEY-HMAC, EVP_KEYMGMT-HMAC, EVP_PKEY-SIPHASH, EVP_KEYMGMT-SIPHASH,
+EVP_PKEY-POLY1305, EVP_KEYMGMT-POLY1305, EVP_PKEY-CMAC, EVP_KEYMGMT-CMAC
+- EVP_PKEY legacy MAC keytypes and algorithm support
+
+=head1 DESCRIPTION
+
+The B<HMAC> and B<CMAC> key types are implemented in OpenSSL's default and FIPS
+providers. Additionally the B<SIPHASH> and B<POLY1305> key types are implemented
+in the default provider. Performing MAC operations via an EVP_PKEY
+is considered legacy and are only available for backwards compatibility purposes
+and for a restricted set of algorithms. The preferred way of performing MAC
+operations is via the EVP_MAC APIs. See L<EVP_MAC_init(3)>.
+
+For further details on using EVP_PKEY based MAC keys see
+L<EVP_SIGNATURE-HMAC(7)>, L<EVP_SIGNATURE-SIPHASH(7)>,
+L<EVP_SIGNATURE-POLY1305(7)> or L<EVP_SIGNATURE-CMAC(7)>.
+
+=head2 Common MAC parameters
+
+All the B<MAC> keytypes support the following parameters.
+
+=over 4
+
+=item "priv" (B<OSSL_PKEY_PARAM_PRIV_KEY>) <octet string>
+
+The MAC key value.
+
+=item "properties" (B<OSSL_PKEY_PARAM_PROPERTIES>) <UTF8 string>
+
+A property query string to be used when any algorithms are fetched.
+
+=back
+
+=head2 CMAC parameters
+
+As well as the parameters described above, the B<CMAC> keytype additionally
+supports the following parameters.
+
+=over 4
+
+=item "cipher" (B<OSSL_PKEY_PARAM_CIPHER>) <UTF8 string>
+
+The name of a cipher to be used when generating the MAC.
+
+=item "engine" (B<OSSL_PKEY_PARAM_ENGINE>) <UTF8 string>
+
+The name of an engine to be used for the specified cipher (if any).
+
+=back
+
+=head2 Common MAC key generation parameters
+
+MAC key generation is unusual in that no new key is actually generated. Instead
+a new provider side key object is created with the supplied raw key value. This
+is done for backwards compatibility with previous versions of OpenSSL.
+
+=over 4
+
+=item "priv" (B<OSSL_PKEY_PARAM_PRIV_KEY>) <octet string>
+
+The MAC key value.
+
+=back
+
+=head2 CMAC key generation parameters
+
+In addition to the common MAC key generation parameters, the CMAC key generation
+additionally recognises the following.
+
+=over 4
+
+=item "cipher" (B<OSSL_PKEY_PARAM_CIPHER>) <UTF8 string>
+
+The name of a cipher to be used when generating the MAC.
+
+=back
+
+=head1 SEE ALSO
+
+L<EVP_KEYMGMT(3)>, L<EVP_PKEY(3)>, L<provider-keymgmt(7)>
+
+=head1 COPYRIGHT
+
+Copyright 2020 The OpenSSL Project Authors. All Rights Reserved.
+
+Licensed under the Apache License 2.0 (the "License").  You may not use
+this file except in compliance with the License.  You can obtain a copy
+in the file LICENSE in the source distribution or at
+L<https://www.openssl.org/source/license.html>.
+
+=cut
diff --git a/doc/man7/EVP_SIGNATURE-HMAC.pod b/doc/man7/EVP_SIGNATURE-HMAC.pod
new file mode 100644
index 0000000000..dd74fae88c
--- /dev/null
+++ b/doc/man7/EVP_SIGNATURE-HMAC.pod
@@ -0,0 +1,41 @@
+=pod
+
+=head1 NAME
+
+EVP_SIGNATURE-HMAC, EVP_SIGNATURE-SIPHASH, EVP_SIGNATURE-POLY1305,
+EVP_SIGNATURE-CMAC
+- The legacy B<EVP_PKEY> MAC signature implementations
+
+=head1 DESCRIPTION
+
+The algorithms described here have legacy support for creating MACs using
+L<EVP_DigestSignInit(3)> and related functions. This is not the preferred way of
+creating MACs. Instead you should use the newer L<EVP_MAC_init(3)> functions.
+This mechanism is provided for backwards compatibility with older versions of
+OpenSSL. 
+
+There are no parameters supported by the legacy EVP_PKEY MAC signature
+algorithms. See L<EVP_PKEY-HMAC(7)>, L<EVP_PKEY-SIPHASH(7)>,
+L<EVP_PKEY-POLY1305(7)> or L<EVP_PKEY-CMAC(7)> for details about parameters that
+are supported during the creation of an EVP_PKEY.
+
+=head1 SEE ALSO
+
+L<EVP_MAC_init(3)>,
+L<EVP_DigestSignInit(3)>,
+L<EVP_PKEY-HMAC(7)>,
+L<EVP_PKEY-SIPHASH(7)>,
+L<EVP_PKEY-POLY1305(7)>,
+L<EVP_PKEY-CMAC(7)>,
+L<provider-signature(7)>,
+
+=head1 COPYRIGHT
+
+Copyright 2020 The OpenSSL Project Authors. All Rights Reserved.
+
+Licensed under the Apache License 2.0 (the "License").  You may not use
+this file except in compliance with the License.  You can obtain a copy
+in the file LICENSE in the source distribution or at
+L<https://www.openssl.org/source/license.html>.
+
+=cut