tls: TLSSocket emits 'error' on handshake failure

Removes branch that would make TLSSocket emit '_tlsError' event if
error occured on handshake and control was not released, as it was
never happening.  Added test for tls.Server to ensure it still emits
'tlsClientError' as expected.

Note that 'tlsClientError' does not exist in the v4.x branch so this
back-port emits 'clientError' instead.  See also pull request nodejs#4557.

Fixes: nodejs#8803
PR-URL: nodejs#8805
Refs: nodejs#4557
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Fedor Indutny <fedor@indutny.com>

lib/_tls_wrap.js

@@ -455,7 +455,9 @@ TLSSocket.prototype._init = function(socket, wrap) {
 
     // Destroy socket if error happened before handshake's finish
     if (!self._secureEstablished) {
-      self.destroy(self._tlsError(err));
+      // When handshake fails control is not yet released,
+      // so self._tlsError will return null instead of actual error
+      self.destroy(err);
     } else if (options.isServer &&
                rejectUnauthorized &&
                /peer did not return a certificate/.test(err.message)) {

test/parallel/test-tls-server-failed-handshake-emits-clienterror.js

@@ -0,0 +1,36 @@
+'use strict';
+const common = require('../common');
+
+if (!common.hasCrypto) {
+  common.skip('missing crypto');
+  return;
+}
+const tls = require('tls');
+const net = require('net');
+const assert = require('assert');
+
+const bonkers = Buffer.alloc(1024, 42);
+
+let clientErrorEmited = false;
+
+const server = tls.createServer({})
+  .listen(0, function() {
+    const c = net.connect({ port: this.address().port }, function() {
+      c.write(bonkers);
+    });
+
+  }).on('clientError', function(e) {
+    clientErrorEmited = true;
+    assert.ok(e instanceof Error,
+              'Instance of Error should be passed to error handler');
+    assert.ok(e.message.match(
+      /SSL routines:SSL23_GET_CLIENT_HELLO:unknown protocol/),
+      'Expecting SSL unknown protocol');
+  });
+
+setTimeout(function() {
+  server.close();
+
+  assert.ok(clientErrorEmited, 'clientError should be emited');
+
+}, common.platformTimeout(200));

test/parallel/test-tls-socket-failed-handshake-emits-error.js

@@ -0,0 +1,38 @@
+'use strict';
+const common = require('../common');
+
+if (!common.hasCrypto) {
+  common.skip('missing crypto');
+  return;
+}
+const tls = require('tls');
+const net = require('net');
+const assert = require('assert');
+
+const bonkers = Buffer.alloc(1024, 42);
+
+const server = net.createServer(function(c) {
+  setTimeout(function() {
+    const s = new tls.TLSSocket(c, {
+      isServer: true,
+      server: server
+    });
+
+    s.on('error', common.mustCall(function(e) {
+      assert.ok(e instanceof Error,
+                'Instance of Error should be passed to error handler');
+      assert.ok(e.message.match(
+        /SSL routines:SSL23_GET_CLIENT_HELLO:unknown protocol/),
+        'Expecting SSL unknown protocol');
+    }));
+
+    s.on('close', function() {
+      server.close();
+      s.destroy();
+    });
+  }, common.platformTimeout(200));
+}).listen(0, function() {
+  const c = net.connect({port: this.address().port}, function() {
+    c.write(bonkers);
+  });
+});