ossl.h: add OSSL_HAVE_PROVIDER macro

With providers, pkeys are immutable and we should avoid using low-level
types such as RSA or EC_KEY.

Use this special macro instead of version numbers to make the intention
clear, and also to make it easier to update when LibreSSL gains
OpenSSL 3.0 providers support.

Author: rhenium

ext/openssl/ossl.h

@@ -56,6 +56,10 @@
 # define OSSL_USE_ENGINE
 #endif
 
+#if OSSL_OPENSSL_PREREQ(3, 0, 0)
+# define OSSL_HAVE_PROVIDER
+#endif
+
 /*
  * Common Module
  */

ext/openssl/ossl_pkey.h

@@ -116,7 +116,7 @@ static VALUE ossl_##_keytype##_get_##_name(VALUE self)			\
 	OSSL_PKEY_BN_DEF_GETTER0(_keytype, _type, a2,			\
 		_type##_get0_##_group(obj, NULL, &bn))
 
-#if !OSSL_OPENSSL_PREREQ(3, 0, 0)
+#ifndef OSSL_HAVE_PROVIDER
 #define OSSL_PKEY_BN_DEF_SETTER3(_keytype, _type, _group, a1, a2, a3)	\
 /*									\
  *  call-seq:								\
@@ -174,7 +174,7 @@ static VALUE ossl_##_keytype##_set_##_group(VALUE self, VALUE v1, VALUE v2) \
 	}								\
 	return self;							\
 }
-#else
+#else /* OSSL_HAVE_PROVIDER */
 #define OSSL_PKEY_BN_DEF_SETTER3(_keytype, _type, _group, a1, a2, a3)	\
 static VALUE ossl_##_keytype##_set_##_group(VALUE self, VALUE v1, VALUE v2, VALUE v3) \
 {									\
@@ -188,7 +188,7 @@ static VALUE ossl_##_keytype##_set_##_group(VALUE self, VALUE v1, VALUE v2) \
         rb_raise(ePKeyError,						\
                  #_keytype"#set_"#_group"= is incompatible with OpenSSL 3.0"); \
 }
-#endif
+#endif /* OSSL_HAVE_PROVIDER */
 
 #define OSSL_PKEY_BN_DEF3(_keytype, _type, _group, a1, a2, a3)		\
 	OSSL_PKEY_BN_DEF_GETTER3(_keytype, _type, _group, a1, a2, a3)	\

ext/openssl/ossl_pkey_ec.c

@@ -248,7 +248,7 @@ ossl_ec_key_get_group(VALUE self)
 static VALUE
 ossl_ec_key_set_group(VALUE self, VALUE group_v)
 {
-#if OSSL_OPENSSL_PREREQ(3, 0, 0)
+#ifdef OSSL_HAVE_PROVIDER
     rb_raise(ePKeyError, "pkeys are immutable on OpenSSL 3.0");
 #else
     EC_KEY *ec;
@@ -290,7 +290,7 @@ static VALUE ossl_ec_key_get_private_key(VALUE self)
  */
 static VALUE ossl_ec_key_set_private_key(VALUE self, VALUE private_key)
 {
-#if OSSL_OPENSSL_PREREQ(3, 0, 0)
+#ifdef OSSL_HAVE_PROVIDER
     rb_raise(ePKeyError, "pkeys are immutable on OpenSSL 3.0");
 #else
     EC_KEY *ec;
@@ -341,7 +341,7 @@ static VALUE ossl_ec_key_get_public_key(VALUE self)
  */
 static VALUE ossl_ec_key_set_public_key(VALUE self, VALUE public_key)
 {
-#if OSSL_OPENSSL_PREREQ(3, 0, 0)
+#ifdef OSSL_HAVE_PROVIDER
     rb_raise(ePKeyError, "pkeys are immutable on OpenSSL 3.0");
 #else
     EC_KEY *ec;
@@ -453,7 +453,7 @@ ossl_ec_key_to_der(VALUE self)
  */
 static VALUE ossl_ec_key_generate_key(VALUE self)
 {
-#if OSSL_OPENSSL_PREREQ(3, 0, 0)
+#ifdef OSSL_HAVE_PROVIDER
     rb_raise(ePKeyError, "pkeys are immutable on OpenSSL 3.0");
 #else
     EC_KEY *ec;