Param build: make structures opaque.

Since this is public, it is best to make the underlying structure opaque.
This means converting from stack allocation to dynamic allocation for all
usages.

Reviewed-by: Nicola Tuveri <nic.tuv@gmail.com>
(Merged from https://github.com/openssl/openssl/pull/11390)

1 files changed, 19 insertions, 16 deletions

diff --git a/crypto/dh/dh_ameth.c b/crypto/dh/dh_ameth.c
index 505211054f..86e78aaf6c 100644
--- a/crypto/dh/dh_ameth.c
+++ b/crypto/dh/dh_ameth.c
@@ -494,13 +494,13 @@ static int dh_pkey_export_to(const EVP_PKEY *from, void *to_keydata,
                              EVP_KEYMGMT *to_keymgmt)
 {
     DH *dh = from->pkey.dh;
-    OSSL_PARAM_BLD tmpl;
+    OSSL_PARAM_BLD *tmpl;
     const BIGNUM *p = DH_get0_p(dh), *g = DH_get0_g(dh), *q = DH_get0_q(dh);
     const BIGNUM *pub_key = DH_get0_pub_key(dh);
     const BIGNUM *priv_key = DH_get0_priv_key(dh);
-    OSSL_PARAM *params;
+    OSSL_PARAM *params = NULL;
     int selection = 0;
-    int rv;
+    int rv = 0;
 
     /*
      * If the DH method is foreign, then we can't be sure of anything, and
@@ -512,35 +512,38 @@ static int dh_pkey_export_to(const EVP_PKEY *from, void *to_keydata,
     if (p == NULL || g == NULL)
         return 0;
 
-    OSSL_PARAM_BLD_init(&tmpl);
-    if (!OSSL_PARAM_BLD_push_BN(&tmpl, OSSL_PKEY_PARAM_FFC_P, p)
-        || !OSSL_PARAM_BLD_push_BN(&tmpl, OSSL_PKEY_PARAM_FFC_G, g))
+    tmpl = OSSL_PARAM_BLD_new();
+    if (tmpl == NULL)
         return 0;
+    if (!OSSL_PARAM_BLD_push_BN(tmpl, OSSL_PKEY_PARAM_FFC_P, p)
+        || !OSSL_PARAM_BLD_push_BN(tmpl, OSSL_PKEY_PARAM_FFC_G, g))
+        goto err;
     if (q != NULL) {
-        if (!OSSL_PARAM_BLD_push_BN(&tmpl, OSSL_PKEY_PARAM_FFC_Q, q))
-            return 0;
+        if (!OSSL_PARAM_BLD_push_BN(tmpl, OSSL_PKEY_PARAM_FFC_Q, q))
+            goto err;
     }
     selection |= OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS;
     if (pub_key != NULL) {
-        if (!OSSL_PARAM_BLD_push_BN(&tmpl, OSSL_PKEY_PARAM_PUB_KEY, pub_key))
-            return 0;
+        if (!OSSL_PARAM_BLD_push_BN(tmpl, OSSL_PKEY_PARAM_PUB_KEY, pub_key))
+            goto err;
         selection |= OSSL_KEYMGMT_SELECT_PUBLIC_KEY;
     }
     if (priv_key != NULL) {
-        if (!OSSL_PARAM_BLD_push_BN(&tmpl, OSSL_PKEY_PARAM_PRIV_KEY,
+        if (!OSSL_PARAM_BLD_push_BN(tmpl, OSSL_PKEY_PARAM_PRIV_KEY,
                                     priv_key))
-            return 0;
+            goto err;
         selection |= OSSL_KEYMGMT_SELECT_PRIVATE_KEY;
     }
 
-    if ((params = OSSL_PARAM_BLD_to_param(&tmpl)) == NULL)
-        return 0;
+    if ((params = OSSL_PARAM_BLD_to_param(tmpl)) == NULL)
+        goto err;
 
     /* We export, the provider imports */
     rv = evp_keymgmt_import(to_keymgmt, to_keydata, selection, params);
 
-    OSSL_PARAM_BLD_free(params);
-
+    OSSL_PARAM_BLD_free_params(params);
+err:
+    OSSL_PARAM_BLD_free(tmpl);
     return rv;
 }