tls, crypto: add DHE support

This also changes the default cipher list as `DHE-RSA-AES128-SHA256`
is added and '!EDH' is explicitly written to
`!EDH-RSA-DES:!EDH-DSS-DES`. In case of an invalid DH parameter file,
it is sliently discarded. To use auto DH parameter in a server and DHE
key length check in a client, we need to wait for the next release of
OpenSSL-1.0.2.

doc/api/tls.markdown

@@ -142,14 +142,16 @@ automatically set as a listener for the [secureConnection][] event.  The
     conjunction with the `honorCipherOrder` option described below to
     prioritize the non-CBC cipher.
 
-    Defaults to `ECDHE-RSA-AES128-SHA256:AES128-GCM-SHA256:RC4:HIGH:!MD5:!aNULL:!EDH`.
-    Consult the [OpenSSL cipher list format documentation] for details on the
-    format.
+    Defaults to
+    `ECDHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA256:AES128-GCM-SHA256:RC4:HIGH:!MD5:!aNULL:!EDH-RSA-DES:!EDH-DSS-DES`.
+    Consult the [OpenSSL cipher list format documentation] for details
+    on the format.
 
-    `ECDHE-RSA-AES128-SHA256` and `AES128-GCM-SHA256` are TLS v1.2 ciphers and
-    used when node.js is linked against OpenSSL 1.0.1 or newer, such as the
-    bundled version of OpenSSL.  Note that it is still possible for a TLS v1.2
-    client to negotiate a weaker cipher unless `honorCipherOrder` is enabled.
+    `ECDHE-RSA-AES128-SHA256`, `DHE-RSA-AES128-SHA256` and
+    `AES128-GCM-SHA256` are TLS v1.2 ciphers and used when node.js is
+    linked against OpenSSL 1.0.1 or newer, such as the bundled version
+    of OpenSSL.  Note that it is still possible for a TLS v1.2 client
+    to negotiate a weaker cipher unless `honorCipherOrder` is enabled.
 
     `RC4` is used as a fallback for clients that speak on older version of
     the TLS protocol.  `RC4` has in recent years come under suspicion and
@@ -165,6 +167,10 @@ automatically set as a listener for the [secureConnection][] event.  The
 
     Defaults to `prime256v1`. Consult [RFC 4492] for more details.
 
+  - `dhparam`: DH parameter file to use for DHE key agreement. Use
+    `openssl dhparam` command to create it. If the file is invalid to
+    load, it is silently discarded.
+
   - `handshakeTimeout`: Abort the connection if the SSL/TLS handshake does not
     finish in this many milliseconds. The default is 120 seconds.
 

lib/_tls_common.js

@@ -97,6 +97,8 @@ exports.createSecureContext = function createSecureContext(options, context) {
   else if (options.ecdhCurve)
     c.context.setECDHCurve(options.ecdhCurve);
 
+  if (options.dhparam) c.context.setDHParam(options.dhparam);
+
   if (options.crl) {
     if (util.isArray(options.crl)) {
       for (var i = 0, len = options.crl.length; i < len; i++) {

lib/_tls_wrap.js

@@ -600,6 +600,7 @@ function Server(/* [options], listener */) {
     ca: self.ca,
     ciphers: self.ciphers,
     ecdhCurve: self.ecdhCurve,
+    dhparam: self.dhparam,
     secureProtocol: self.secureProtocol,
     secureOptions: self.secureOptions,
     honorCipherOrder: self.honorCipherOrder,
@@ -718,6 +719,7 @@ Server.prototype.setOptions = function(options) {
   if (options.ciphers) this.ciphers = options.ciphers;
   if (!util.isUndefined(options.ecdhCurve))
     this.ecdhCurve = options.ecdhCurve;
+  if (options.dhparam) this.dhparam = options.dhparam;
   if (options.sessionTimeout) this.sessionTimeout = options.sessionTimeout;
   if (options.ticketKeys) this.ticketKeys = options.ticketKeys;
   var secureOptions = options.secureOptions || 0;

lib/tls.js

@@ -33,8 +33,10 @@ exports.CLIENT_RENEG_WINDOW = 600;
 exports.SLAB_BUFFER_SIZE = 10 * 1024 * 1024;
 
 exports.DEFAULT_CIPHERS =
-    'ECDHE-RSA-AES128-SHA256:AES128-GCM-SHA256:' + // TLS 1.2
-    'RC4:HIGH:!MD5:!aNULL:!EDH';                   // TLS 1.0
+    // TLS 1.2
+    'ECDHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA256:AES128-GCM-SHA256:' +
+    // TLS 1.0
+    'RC4:HIGH:!MD5:!aNULL:!EDH-RSA-DES:!EDH-DSS-DES';
 
 exports.DEFAULT_ECDH_CURVE = 'prime256v1';
 

src/node_crypto.cc

@@ -270,6 +270,7 @@ void SecureContext::Initialize(Environment* env, Handle<Object> target) {
   NODE_SET_PROTOTYPE_METHOD(t, "addRootCerts", SecureContext::AddRootCerts);
   NODE_SET_PROTOTYPE_METHOD(t, "setCiphers", SecureContext::SetCiphers);
   NODE_SET_PROTOTYPE_METHOD(t, "setECDHCurve", SecureContext::SetECDHCurve);
+  NODE_SET_PROTOTYPE_METHOD(t, "setDHParam", SecureContext::SetDHParam);
   NODE_SET_PROTOTYPE_METHOD(t, "setOptions", SecureContext::SetOptions);
   NODE_SET_PROTOTYPE_METHOD(t, "setSessionIdContext",
                                SecureContext::SetSessionIdContext);
@@ -746,6 +747,38 @@ void SecureContext::SetECDHCurve(const FunctionCallbackInfo<Value>& args) {
 }
 
 
+void SecureContext::SetDHParam(const FunctionCallbackInfo<Value>& args) {
+  HandleScope scope(args.GetIsolate());
+
+  SecureContext* sc = Unwrap<SecureContext>(args.This());
+  Environment* env = sc->env();
+
+  // Auto DH is not supported in openssl 1.0.1, so dhparam needs
+  // to be specifed explicitly
+  if (args.Length() != 1) {
+    return env->ThrowTypeError("Bad parameter");
+  }
+
+  // Invalid dhparam is silently discarded and DHE is no longer used.
+  BIO *bio = LoadBIO(env, args[0]);
+  if (!bio)
+    return;
+
+  DH *dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL);
+
+  if(dh == NULL) {
+    goto exit;
+  }
+
+  SSL_CTX_set_options(sc->ctx_, SSL_OP_SINGLE_DH_USE);
+  SSL_CTX_set_tmp_dh(sc->ctx_, dh);
+
+exit:
+  DH_free(dh);
+  BIO_free(bio);
+}
+
+
 void SecureContext::SetOptions(const FunctionCallbackInfo<Value>& args) {
   HandleScope scope(args.GetIsolate());
 

src/node_crypto.h

@@ -93,6 +93,7 @@ class SecureContext : public BaseObject {
   static void AddRootCerts(const v8::FunctionCallbackInfo<v8::Value>& args);
   static void SetCiphers(const v8::FunctionCallbackInfo<v8::Value>& args);
   static void SetECDHCurve(const v8::FunctionCallbackInfo<v8::Value>& args);
+  static void SetDHParam(const v8::FunctionCallbackInfo<v8::Value>& args);
   static void SetOptions(const v8::FunctionCallbackInfo<v8::Value>& args);
   static void SetSessionIdContext(
       const v8::FunctionCallbackInfo<v8::Value>& args);

test/fixtures/test_dh1024.pem

@@ -0,0 +1,5 @@
+-----BEGIN DH PARAMETERS-----
+MIGHAoGBALDYoJasveNejxRyF3d9p7+OF6ALf9MzJD4FJqEO1YDEfrfE4I75HTcU
+y+h72WZXgGyI8ySUPvRs8t7W2N+0SRTKJmQnd2uKVyp0pFx5DG7TTy8DK+MFRMeh
+8Tz7TptcSHktZNmLo4Cxda7IsfaKUagNhku3Ks6HS2Gg6FHkdb4zAgEC
+-----END DH PARAMETERS-----

test/fixtures/test_dh2048.pem

@@ -0,0 +1,8 @@
+-----BEGIN DH PARAMETERS-----
+MIIBCAKCAQEAxhRvhunS9qXXGuT1OqTfiFzDgqfyzFWt4uCN38tDODkf6z57MyZJ
+6WsKExHeuNpfxS6XI0GOEWnYJqZP1+cMm8Gg2VNX0pI634tt/861ZnoWXQvOf2xa
+KOBYMW/e8DmiIfQ9szqECCuY2FBG7CJC9RqI4FTYEkbR3MGAfVqxm5/4nRdUwQIj
+V6jakbZ8EpKkk44iA4LBuLiR6BaLCbawK0rvdjaTTXWItMtRx5iMcSxrqaqBgA0v
+Vp7EMqmKKDGJVzq5+Rbir9HUwZxBo95SolpL5D3scJoVTqYf2oTSHxqkdqtzadVl
+Lq0OvBEfhX1oTPnJBH6GW+zmh462dfmlGwIBAg==
+-----END DH PARAMETERS-----

test/fixtures/test_dh4096.pem

@@ -0,0 +1,13 @@
+-----BEGIN DH PARAMETERS-----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=
+-----END DH PARAMETERS-----

test/fixtures/test_dh512.pem

@@ -0,0 +1,4 @@
+-----BEGIN DH PARAMETERS-----
+MEYCQQDGhoPGQ171hbuBJoGSPxqcmJbBt0ZaVL3ZjZy79/9vlkQHtXrXbxKhj2vg
+SLNu/Sfav5RTZjJpj21cKBWYDZB7AgEC
+-----END DH PARAMETERS-----

test/fixtures/test_dherror.pem

@@ -0,0 +1,3 @@
+-----BEGIN DH PARAMETERS-----
+AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
+-----END DH PARAMETERS-----

test/simple/test-tls-dhe.js

@@ -0,0 +1,109 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+var common = require('../common');
+
+if (!common.opensslCli) {
+  console.error('Skipping because node compiled without OpenSSL CLI.');
+  process.exit(0);
+}
+
+var assert = require('assert');
+var spawn = require('child_process').spawn;
+var tls = require('tls');
+var fs = require('fs');
+var key =  fs.readFileSync(common.fixturesDir + '/keys/agent2-key.pem');
+var cert = fs.readFileSync(common.fixturesDir + '/keys/agent2-cert.pem');
+var nsuccess = 0;
+var ntests = 0;
+var ciphers = 'DHE-RSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256';
+
+function loadDHParam(n) {
+  return fs.readFileSync(common.fixturesDir + '/test_dh' + n + '.pem');
+}
+
+function test(keylen, expectedCipher, cb) {
+  var options = {
+    key: key,
+    cert: cert,
+    dhparam: loadDHParam(keylen)
+  };
+
+  var server = tls.createServer(options, function(conn) {
+    conn.end();
+  });
+
+  server.on('close', function(err) {
+    assert(!err);
+    if (cb) cb();
+  });
+
+  server.listen(common.PORT, '127.0.0.1', function() {
+    var args = ['s_client', '-connect', '127.0.0.1:' + common.PORT,
+                '-cipher', ciphers];
+    var client = spawn(common.opensslCli, args);
+    var out = '';
+    client.stdout.setEncoding('utf8');
+    client.stdout.on('data', function(d) {
+      out += d;
+    });
+    client.stdout.on('end', function() {
+      // DHE key length can be checked -brief option in s_client but it
+      // is only supported in openssl 1.0.2 so we cannot check it.
+      var reg = new RegExp('Cipher    : ' + expectedCipher);
+      if (reg.test(out)) {
+        nsuccess++;
+        server.close();
+      }
+    });
+  });
+}
+
+function test512() {
+  test(512, 'DHE-RSA-AES128-SHA256', test1024);
+  ntests++;
+}
+
+function test1024() {
+  test(1024, 'DHE-RSA-AES128-SHA256', test2048);
+  ntests++;
+}
+
+function test2048() {
+  test(2048, 'DHE-RSA-AES128-SHA256', test4096);
+  ntests++;
+}
+
+function test4096() {
+  test(4096, 'DHE-RSA-AES128-SHA256', testError);
+  ntests++;
+}
+
+function testError() {
+  test('error', 'ECDHE-RSA-AES128-SHA256', null);
+  ntests++;
+}
+
+test512();
+
+process.on('exit', function() {
+  assert.equal(ntests, nsuccess);
+});