Prepare to provide EVP_PKEY_{public,param}_check

This implements checking of a public key and of key generation
parameters for DH and EC keys. With the same logic and setters
and const quirks as for EVP_PKEY_check().

There are a couple of quirks: For DH no default EVP_PKEY_check()
is implemented, instead EVP_PKEY_param_check() calls DH_check_ex()
even though DH_param_check_ex() was added for this purpose.
EVP_PKEY_public_check() for EC curves also checks the private key
if present.

ok inoguchi jsing

1 files changed, 43 insertions, 1 deletions

diff --git a/src/lib/libcrypto/evp/pmeth_gn.c b/src/lib/libcrypto/evp/pmeth_gn.c
index a8a4cc97db..7d921d23b4 100644
--- a/src/lib/libcrypto/evp/pmeth_gn.c
+++ b/src/lib/libcrypto/evp/pmeth_gn.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: pmeth_gn.c,v 1.9 2022/01/10 11:52:43 tb Exp $ */
+/* $OpenBSD: pmeth_gn.c,v 1.10 2022/01/10 12:10:26 tb Exp $ */
 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
  * project 2006.
  */
@@ -244,3 +244,45 @@ EVP_PKEY_check(EVP_PKEY_CTX *ctx)
 
         return pkey->ameth->pkey_check(pkey);
 }
+
+int
+EVP_PKEY_public_check(EVP_PKEY_CTX *ctx)
+{
+        EVP_PKEY *pkey;
+
+        if ((pkey = ctx->pkey) == NULL) {
+                EVPerror(EVP_R_NO_KEY_SET);
+                return 0;
+        }
+
+        if (ctx->pmeth->public_check != NULL)
+                return ctx->pmeth->public_check(pkey);
+
+        if (pkey->ameth == NULL || pkey->ameth->pkey_public_check == NULL) {
+                EVPerror(EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
+                return -2;
+        }
+
+        return pkey->ameth->pkey_public_check(pkey);
+}
+
+int
+EVP_PKEY_param_check(EVP_PKEY_CTX *ctx)
+{
+        EVP_PKEY *pkey;
+
+        if ((pkey = ctx->pkey) == NULL) {
+                EVPerror(EVP_R_NO_KEY_SET);
+                return 0;
+        }
+
+        if (ctx->pmeth->param_check != NULL)
+                return ctx->pmeth->param_check(pkey);
+
+        if (pkey->ameth == NULL || pkey->ameth->pkey_param_check == NULL) {
+                EVPerror(EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
+                return -2;
+        }
+
+        return pkey->ameth->pkey_param_check(pkey);
+}