Use correct ifdefs for LibreSSL support

- TLS 1.3 is not ready yet in LibreSSL. Also there is a theoretical
possibility of OpenSSL >=1.1.1 built without TLS 1.3 support.
- EC_KEY_METHOD API and SSL_get1_supported_ciphers are added into LibreSSL
master (not yet released in 2.9.0).
- Some methods that are available since LibreSSL 2.7.0 were thrown away
in ssl_openssl.c regardless of LibreSSL version. Use them with newer
LibreSSL.

Signed-off-by: Stefan Strogin <stefan.strogin@gmail.com>
Acked-by: Arne Schwabe <arne@rfc2549.org>
Message-Id: <20190225183531.27399-1-stefan.strogin@gmail.com>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg18239.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>

src/openvpn/ssl_openssl.c

@@ -465,7 +465,7 @@ tls_ctx_restrict_ciphers_tls13(struct tls_root_ctx *ctx, const char *ciphers)
         return;
     }
 
-#if (OPENSSL_VERSION_NUMBER < 0x1010100fL)
+#if !defined(TLS1_3_VERSION)
     crypto_msg(M_WARN, "Not compiled with OpenSSL 1.1.1 or higher. "
                "Ignoring TLS 1.3 only tls-ciphersuites '%s' setting.",
                ciphers);
@@ -526,7 +526,8 @@ tls_ctx_check_cert_time(const struct tls_root_ctx *ctx)
 
     ASSERT(ctx);
 
-#if OPENSSL_VERSION_NUMBER >= 0x10002000L && !defined(LIBRESSL_VERSION_NUMBER)
+#if (OPENSSL_VERSION_NUMBER >= 0x10002000L && !defined(LIBRESSL_VERSION_NUMBER)) \
+    || LIBRESSL_VERSION_NUMBER >= 0x2070000fL
     /* OpenSSL 1.0.2 and up */
     cert = SSL_CTX_get0_certificate(ctx->ctx);
 #else
@@ -561,7 +562,8 @@ tls_ctx_check_cert_time(const struct tls_root_ctx *ctx)
     }
 
 cleanup:
-#if OPENSSL_VERSION_NUMBER < 0x10002000L || defined(LIBRESSL_VERSION_NUMBER)
+#if OPENSSL_VERSION_NUMBER < 0x10002000L \
+    || (defined(LIBRESSL_VERSION_NUMBER) && LIBRESSL_VERSION_NUMBER < 0x2070000fL)
     SSL_free(ssl);
 #endif
     return;
@@ -1209,7 +1211,9 @@ tls_ctx_use_external_rsa_key(struct tls_root_ctx *ctx, EVP_PKEY *pkey)
     return 0;
 }
 
-#if OPENSSL_VERSION_NUMBER > 0x10100000L && !defined(OPENSSL_NO_EC) && !defined(LIBRESSL_VERSION_NUMBER)
+#if ((OPENSSL_VERSION_NUMBER > 0x10100000L && !defined(LIBRESSL_VERSION_NUMBER)) \
+     || LIBRESSL_VERSION_NUMBER > 0x2090000fL) \
+    && !defined(OPENSSL_NO_EC)
 
 /* called when EC_KEY is destroyed */
 static void
@@ -1331,7 +1335,7 @@ tls_ctx_use_external_ec_key(struct tls_root_ctx *ctx, EVP_PKEY *pkey)
     }
     return 0;
 }
-#endif /* OPENSSL_VERSION_NUMBER > 1.1.0 dev */
+#endif /* OPENSSL_VERSION_NUMBER > 1.1.0 dev && !defined(OPENSSL_NO_EC) */
 
 int
 tls_ctx_use_management_external_key(struct tls_root_ctx *ctx)
@@ -1340,7 +1344,8 @@ tls_ctx_use_management_external_key(struct tls_root_ctx *ctx)
 
     ASSERT(NULL != ctx);
 
-#if OPENSSL_VERSION_NUMBER >= 0x10002000L && !defined(LIBRESSL_VERSION_NUMBER)
+#if (OPENSSL_VERSION_NUMBER >= 0x10002000L && !defined(LIBRESSL_VERSION_NUMBER)) \
+    || LIBRESSL_VERSION_NUMBER >= 0x2070000fL
     /* OpenSSL 1.0.2 and up */
     X509 *cert = SSL_CTX_get0_certificate(ctx->ctx);
 #else
@@ -1362,7 +1367,9 @@ tls_ctx_use_management_external_key(struct tls_root_ctx *ctx)
             goto cleanup;
         }
     }
-#if OPENSSL_VERSION_NUMBER > 0x10100000L && !defined(OPENSSL_NO_EC) && !defined(LIBRESSL_VERSION_NUMBER)
+#if ((OPENSSL_VERSION_NUMBER > 0x10100000L && !defined(LIBRESSL_VERSION_NUMBER)) \
+     || LIBRESSL_VERSION_NUMBER > 0x2090000fL) \
+    && !defined(OPENSSL_NO_EC)
     else if (EVP_PKEY_id(pkey) == EVP_PKEY_EC)
     {
         if (!tls_ctx_use_external_ec_key(ctx, pkey))
@@ -1375,17 +1382,18 @@ tls_ctx_use_management_external_key(struct tls_root_ctx *ctx)
         crypto_msg(M_WARN, "management-external-key requires an RSA or EC certificate");
         goto cleanup;
     }
-#else  /* if OPENSSL_VERSION_NUMBER > 0x10100000L && !defined(OPENSSL_NO_EC) && !defined(LIBRESSL_VERSION_NUMBER) */
+#else  /* OPENSSL_VERSION_NUMBER > 1.1.0 dev && !defined(OPENSSL_NO_EC) */
     else
     {
         crypto_msg(M_WARN, "management-external-key requires an RSA certificate");
         goto cleanup;
     }
-#endif /* OPENSSL_VERSION_NUMBER > 1.1.0 dev */
+#endif /* OPENSSL_VERSION_NUMBER > 1.1.0 dev && !defined(OPENSSL_NO_EC) */
 
     ret = 0;
 cleanup:
-#if OPENSSL_VERSION_NUMBER < 0x10002000L || defined(LIBRESSL_VERSION_NUMBER)
+#if OPENSSL_VERSION_NUMBER < 0x10002000L \
+    || (defined(LIBRESSL_VERSION_NUMBER) && LIBRESSL_VERSION_NUMBER < 0x2070000fL)
     if (ssl)
     {
         SSL_free(ssl);
@@ -1998,7 +2006,7 @@ show_available_tls_ciphers_list(const char *cipher_list,
         crypto_msg(M_FATAL, "Cannot create SSL_CTX object");
     }
 
-#if (OPENSSL_VERSION_NUMBER >= 0x1010100fL)
+#if defined(TLS1_3_VERSION)
     if (tls13)
     {
         SSL_CTX_set_min_proto_version(tls_ctx.ctx, TLS1_3_VERSION);
@@ -2019,7 +2027,8 @@ show_available_tls_ciphers_list(const char *cipher_list,
         crypto_msg(M_FATAL, "Cannot create SSL object");
     }
 
-#if (OPENSSL_VERSION_NUMBER < 0x1010000fL)
+#if (OPENSSL_VERSION_NUMBER < 0x1010000fL) || \
+    (defined(LIBRESSL_VERSION_NUMBER) && LIBRESSL_VERSION_NUMBER <= 0x2090000fL)
     STACK_OF(SSL_CIPHER) *sk = SSL_get_ciphers(ssl);
 #else
     STACK_OF(SSL_CIPHER) *sk = SSL_get1_supported_ciphers(ssl);