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, 25 insertions, 1 deletions

diff --git a/src/lib/libcrypto/ec/ec_ameth.c b/src/lib/libcrypto/ec/ec_ameth.c
index 8316683f8f..86f509b736 100644
--- a/src/lib/libcrypto/ec/ec_ameth.c
+++ b/src/lib/libcrypto/ec/ec_ameth.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ec_ameth.c,v 1.30 2022/01/10 11:52:43 tb Exp $ */
+/* $OpenBSD: ec_ameth.c,v 1.31 2022/01/10 12:10:26 tb Exp $ */
 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
  * project 2006.
  */
@@ -634,6 +634,28 @@ ec_pkey_check(const EVP_PKEY *pkey)
         return EC_KEY_check_key(eckey);
 }
 
+static int
+ec_pkey_public_check(const EVP_PKEY *pkey)
+{
+        EC_KEY *eckey = pkey->pkey.ec;
+
+        /* This also checks the private key, but oh, well... */
+        return EC_KEY_check_key(eckey);
+}
+
+static int
+ec_pkey_param_check(const EVP_PKEY *pkey)
+{
+        EC_KEY *eckey = pkey->pkey.ec;
+
+        if (eckey->group == NULL) {
+                ECerror(EC_R_MISSING_PARAMETERS);
+                return 0;
+        }
+
+        return EC_GROUP_check(eckey->group, NULL);
+}
+
 #ifndef OPENSSL_NO_CMS
 
 static int
@@ -998,4 +1020,6 @@ const EVP_PKEY_ASN1_METHOD eckey_asn1_meth = {
         .old_priv_encode = old_ec_priv_encode,
 
         .pkey_check = ec_pkey_check,
+        .pkey_public_check = ec_pkey_public_check,
+        .pkey_param_check = ec_pkey_param_check,
 };