tls: re-define max supported version as 1.2

Several secureProtocol strings allow any supported TLS version as the
maximum, but our maximum supported protocol version is TLSv1.2 even if
someone configures a build against an OpenSSL that supports TLSv1.3.

Fixes: #24658

PR-URL: #25024
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Daniel Bevenius <daniel.bevenius@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

src/node_crypto.cc

@@ -484,6 +484,12 @@ void SecureContext::Init(const FunctionCallbackInfo<Value>& args) {
  SSL_SESS_CACHE_NO_AUTO_CLEAR);
 
  SSL_CTX_set_min_proto_version(sc->ctx_.get(), min_version);
+
+ if (max_version == 0) {
+ // Selecting some secureProtocol methods allows the TLS version to be "any
+ // supported", but we don't support TLSv1.3, even if OpenSSL does.
+ max_version = TLS1_2_VERSION;
+ }
  SSL_CTX_set_max_proto_version(sc->ctx_.get(), max_version);
  // OpenSSL 1.1.0 changed the ticket key size, but the OpenSSL 1.0.x size was
  // exposed in the public API. To retain compatibility, install a callback