Add OSSL_PARAM_dup() and OSSL_PARAM_merge().

These functions are prerequisites for implementing EVP_PKEY_todata().

OSSL_PARAM_dup() is required to make a deep copy of the exported
params (since the provider export() uses a OSSL_PARAM_BLD which throws away the
data after the call), and then use OSSL_PARAM_merge() to add some additional params
that can be passed to the EVP_PKEY_todata().

Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/14785)

3 files changed, 66 insertions, 1 deletions

diff --git a/doc/build.info b/doc/build.info
index 7ac089005d..899a142f52 100644
--- a/doc/build.info
+++ b/doc/build.info
@@ -1626,6 +1626,10 @@ DEPEND[html/man3/OSSL_PARAM_allocate_from_text.html]=man3/OSSL_PARAM_allocate_fr
 GENERATE[html/man3/OSSL_PARAM_allocate_from_text.html]=man3/OSSL_PARAM_allocate_from_text.pod
 DEPEND[man/man3/OSSL_PARAM_allocate_from_text.3]=man3/OSSL_PARAM_allocate_from_text.pod
 GENERATE[man/man3/OSSL_PARAM_allocate_from_text.3]=man3/OSSL_PARAM_allocate_from_text.pod
+DEPEND[html/man3/OSSL_PARAM_dup.html]=man3/OSSL_PARAM_dup.pod
+GENERATE[html/man3/OSSL_PARAM_dup.html]=man3/OSSL_PARAM_dup.pod
+DEPEND[man/man3/OSSL_PARAM_dup.3]=man3/OSSL_PARAM_dup.pod
+GENERATE[man/man3/OSSL_PARAM_dup.3]=man3/OSSL_PARAM_dup.pod
 DEPEND[html/man3/OSSL_PARAM_int.html]=man3/OSSL_PARAM_int.pod
 GENERATE[html/man3/OSSL_PARAM_int.html]=man3/OSSL_PARAM_int.pod
 DEPEND[man/man3/OSSL_PARAM_int.3]=man3/OSSL_PARAM_int.pod
@@ -3048,6 +3052,7 @@ html/man3/OSSL_LIB_CTX.html \
 html/man3/OSSL_PARAM.html \
 html/man3/OSSL_PARAM_BLD.html \
 html/man3/OSSL_PARAM_allocate_from_text.html \
+html/man3/OSSL_PARAM_dup.html \
 html/man3/OSSL_PARAM_int.html \
 html/man3/OSSL_PROVIDER.html \
 html/man3/OSSL_SELF_TEST_new.html \
@@ -3621,6 +3626,7 @@ man/man3/OSSL_LIB_CTX.3 \
 man/man3/OSSL_PARAM.3 \
 man/man3/OSSL_PARAM_BLD.3 \
 man/man3/OSSL_PARAM_allocate_from_text.3 \
+man/man3/OSSL_PARAM_dup.3 \
 man/man3/OSSL_PARAM_int.3 \
 man/man3/OSSL_PROVIDER.3 \
 man/man3/OSSL_SELF_TEST_new.3 \
diff --git a/doc/man3/OSSL_PARAM.pod b/doc/man3/OSSL_PARAM.pod
index a872de3b77..593bb21ef1 100644
--- a/doc/man3/OSSL_PARAM.pod
+++ b/doc/man3/OSSL_PARAM.pod
@@ -342,7 +342,7 @@ could fill in the parameters like this:
 
 =head1 SEE ALSO
 
-L<openssl-core.h(7)>, L<OSSL_PARAM_get_int(3)>
+L<openssl-core.h(7)>, L<OSSL_PARAM_get_int(3)>, L<OSSL_PARAM_dup(3)>
 
 =head1 HISTORY
 
diff --git a/doc/man3/OSSL_PARAM_dup.pod b/doc/man3/OSSL_PARAM_dup.pod
new file mode 100644
index 0000000000..5130c9e1dc
--- /dev/null
+++ b/doc/man3/OSSL_PARAM_dup.pod
@@ -0,0 +1,59 @@
+=pod
+
+=head1 NAME
+
+OSSL_PARAM_dup, OSSL_PARAM_merge, OSSL_PARAM_free
+- OSSL_PARAM array copy functions
+
+=head1 SYNOPSIS
+
+ #include <openssl/params.h>
+
+ OSSL_PARAM *OSSL_PARAM_dup(const OSSL_PARAM *params);
+ OSSL_PARAM *OSSL_PARAM_merge(const OSSL_PARAM *params, const OSSL_PARAM *params1);
+ void OSSL_PARAM_free(OSSL_PARAM *params);
+
+=head1 DESCRIPTION
+
+Algorithm parameters can be exported/imported from/to providers using arrays of
+B<OSSL_PARAM>. The following utility functions allow the parameters to be
+duplicated and merged with other B<OSSL_PARAM> to assist in this process.
+
+OSSL_PARAM_dup() duplicates the parameter array I<params>. This function does a
+deep copy of the data.
+
+OSSL_PARAM_merge() merges the parameter arrays I<params> and I<params1> into a
+new parameter array. If I<params> and I<params1> contain values with the same
+'key' then the value from I<params1> will replace the I<param> value. This
+function does a shallow copy of the parameters. Either I<params> or I<params1>
+may be NULL. The behaviour of the merge is unpredictable if I<params> and
+I<params1> contain the same key, and there are multiple entries within either
+array that have the same key.
+
+OSSL_PARAM_free() frees the parameter array I<params> that was created using
+OSSL_PARAM_dup(), OSSL_PARAM_merge() or OSSL_PARAM_BLD_to_param().
+
+=head1 RETURN VALUES
+
+The functions OSSL_PARAM_dup() and OSSL_PARAM_merge() return a newly allocated
+B<OSSL_PARAM> array, or NULL if there was an error. If both parameters are NULL
+ then NULL is returned.
+
+=head1 SEE ALSO
+
+L<OSSL_PARAM(3)>, L<OSSL_PARAM_BLD(3)>
+
+=head1 HISTORY
+
+The functions were added in OpenSSL 3.0.
+
+=head1 COPYRIGHT
+
+Copyright 2021 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