EVP: Add the internal convenience function evp_keymgmt_util_export()

This is purely to allow exporting without having to repeatedly specify
the keymgmt and keydata from the EVP_PKEY.

Reviewed-by: Nicola Tuveri <nic.tuv@gmail.com>
Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/12853)

crypto/evp/keymgmt_lib.c

@@ -77,6 +77,13 @@ EVP_PKEY *evp_keymgmt_util_make_pkey(EVP_KEYMGMT *keymgmt, void *keydata)
     return pkey;
 }
 
+int evp_keymgmt_util_export(const EVP_PKEY *pk, int selection,
+                            OSSL_CALLBACK *export_cb, void *export_cbarg)
+{
+    return evp_keymgmt_export(pk->keymgmt, pk->keydata, selection,
+                              export_cb, export_cbarg);
+}
+
 void *evp_keymgmt_util_export_to_provider(EVP_PKEY *pk, EVP_KEYMGMT *keymgmt)
 {
     struct evp_keymgmt_util_try_import_data_st import_data;
@@ -139,8 +146,8 @@ void *evp_keymgmt_util_export_to_provider(EVP_PKEY *pk, EVP_KEYMGMT *keymgmt)
      * The export function calls the callback (evp_keymgmt_util_try_import),
      * which does the import for us.  If successful, we're done.
      */
-    if (!evp_keymgmt_export(pk->keymgmt, pk->keydata, OSSL_KEYMGMT_SELECT_ALL,
-                            &evp_keymgmt_util_try_import, &import_data)) {
+    if (!evp_keymgmt_util_export(pk, OSSL_KEYMGMT_SELECT_ALL,
+                                 &evp_keymgmt_util_try_import, &import_data)) {
         /* If there was an error, bail out */
         evp_keymgmt_freedata(keymgmt, import_data.keydata);
         return NULL;
@@ -392,8 +399,9 @@ int evp_keymgmt_util_copy(EVP_PKEY *to, EVP_PKEY *from, int selection)
         import_data.keydata = to_keydata;
         import_data.selection = selection;
 
-        if (!evp_keymgmt_export(from->keymgmt, from->keydata, selection,
-                                &evp_keymgmt_util_try_import, &import_data)) {
+        if (!evp_keymgmt_util_export(from, selection,
+                                     &evp_keymgmt_util_try_import,
+                                     &import_data)) {
             evp_keymgmt_freedata(to_keymgmt, alloc_keydata);
             return 0;
         }

crypto/evp/p_lib.c

@@ -527,9 +527,8 @@ int EVP_PKEY_get_raw_private_key(const EVP_PKEY *pkey, unsigned char *priv,
         raw_key.len = len;
         raw_key.selection = OSSL_KEYMGMT_SELECT_PRIVATE_KEY;
 
-        return evp_keymgmt_export(pkey->keymgmt, pkey->keydata,
-                                  OSSL_KEYMGMT_SELECT_PRIVATE_KEY,
-                                  get_raw_key_details, &raw_key);
+        return evp_keymgmt_util_export(pkey, OSSL_KEYMGMT_SELECT_PRIVATE_KEY,
+                                       get_raw_key_details, &raw_key);
     }
 
     if (pkey->ameth == NULL) {
@@ -560,9 +559,8 @@ int EVP_PKEY_get_raw_public_key(const EVP_PKEY *pkey, unsigned char *pub,
         raw_key.len = len;
         raw_key.selection = OSSL_KEYMGMT_SELECT_PUBLIC_KEY;
 
-        return evp_keymgmt_export(pkey->keymgmt, pkey->keydata,
-                                  OSSL_KEYMGMT_SELECT_PUBLIC_KEY,
-                                  get_raw_key_details, &raw_key);
+        return evp_keymgmt_util_export(pkey, OSSL_KEYMGMT_SELECT_PUBLIC_KEY,
+                                       get_raw_key_details, &raw_key);
     }
 
     if (pkey->ameth == NULL) {
@@ -1115,9 +1113,9 @@ int evp_pkey_get_EC_KEY_curve_nid(const EVP_PKEY *pkey)
     } else if (EVP_PKEY_is_a(pkey, "EC") || EVP_PKEY_is_a(pkey, "SM2")) {
         char *curve_name = NULL;
 
-        ret = evp_keymgmt_export(pkey->keymgmt, pkey->keydata,
-                                 OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS,
-                                 get_ec_curve_name_cb, &curve_name);
+        ret = evp_keymgmt_util_export(pkey,
+                                      OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS,
+                                      get_ec_curve_name_cb, &curve_name);
         if (ret)
             ret = ec_curve_name2nid(curve_name);
         OPENSSL_free(curve_name);

doc/internal/man3/evp_keymgmt_util_export_to_provider.pod

@@ -2,6 +2,7 @@
 
 =head1 NAME
 
+evp_keymgmt_util_export,
 evp_keymgmt_util_export_to_provider,
 evp_keymgmt_util_find_operation_cache_index,
 evp_keymgmt_util_clear_operation_cache,
@@ -14,6 +15,8 @@ evp_keymgmt_util_fromdata
 
  #include "crypto/evp.h"
 
+ int evp_keymgmt_util_export(const EVP_PKEY *pk, int selection,
+                             OSSL_CALLBACK *export_cb, void *export_cbarg);
  void *evp_keymgmt_util_export_to_provider(EVP_PKEY *pk, EVP_KEYMGMT *keymgmt);
  size_t evp_keymgmt_util_find_operation_cache_index(EVP_PKEY *pk,
                                                     EVP_KEYMGMT *keymgmt);
@@ -26,6 +29,9 @@ evp_keymgmt_util_fromdata
 
 =head1 DESCRIPTION
 
+evp_keymgmt_util_export() calls L<evp_keymgmt_export(3)> with the
+I<keymgmt> and I<keydata> from I<pk>.  This is a convenience function.
+
 evp_keymgmt_util_export_to_provider() exports cached key material
 (provider side key material) from the given key I<pk> to a provider
 via a B<EVP_KEYMGMT> interface, if this hasn't already been done.

include/crypto/evp.h

@@ -696,6 +696,8 @@ int evp_keymgmt_util_assign_pkey(EVP_PKEY *pkey, EVP_KEYMGMT *keymgmt,
                                  void *keydata);
 EVP_PKEY *evp_keymgmt_util_make_pkey(EVP_KEYMGMT *keymgmt, void *keydata);
 
+int evp_keymgmt_util_export(const EVP_PKEY *pk, int selection,
+                            OSSL_CALLBACK *export_cb, void *export_cbarg);
 void *evp_keymgmt_util_export_to_provider(EVP_PKEY *pk, EVP_KEYMGMT *keymgmt);
 size_t evp_keymgmt_util_find_operation_cache_index(EVP_PKEY *pk,
                                                    EVP_KEYMGMT *keymgmt);