crypto,tls: remove SSLv2 support

Remove support for SSLv2 because of DROWN (CVE-2016-0800).

Use of the `--enable-ssl2` flag is now an error; node will print an
error message and exit.

Fixes: https://github.com/nodejs/LTS/issues/80
PR-URL: https://github.com/nodejs/node/pull/5529
Reviewed-By: Rod Vagg <rod@vagg.org>

configure

@@ -112,11 +112,6 @@ parser.add_option("--systemtap-includes",
     dest="systemtap_includes",
     help=optparse.SUPPRESS_HELP)
 
-parser.add_option("--without-ssl2",
-    action="store_true",
-    dest="ssl2",
-    help="Disable SSL v2")
-
 parser.add_option("--without-ssl3",
     action="store_true",
     dest="ssl3",
@@ -632,9 +627,6 @@ def configure_openssl(o):
   if options.without_ssl:
     return
 
-  if options.ssl2:
-    o['defines'] += ['OPENSSL_NO_SSL2=1']
-
   if options.ssl3:
     o['defines'] += ['OPENSSL_NO_SSL3=1']
 

deps/openssl/openssl.gyp

@@ -1093,13 +1093,19 @@
       'L_ENDIAN',
       'PURIFY',
       '_REENTRANT',
-
+      'OPENSSL_NO_SSL2',
       # Heartbeat is a TLS extension, that couldn't be turned off or
       # asked to be not advertised. Unfortunately this is unacceptable for
       # Microsoft's IIS, which seems to be ignoring whole ClientHello after
       # seeing this extension.
       'OPENSSL_NO_HEARTBEATS',
     ],
+    'direct_dependent_settings': {
+      'defines': [
+        'OPENSSL_NO_SSL2',
+        'OPENSSL_NO_HEARTBEATS',
+      ],
+    },
     'conditions': [
       ['OS=="win"', {
         'defines': [

lib/crypto.js

@@ -67,9 +67,6 @@ function getSecureOptions(secureProtocol, secureOptions) {
 
     if (!binding.SSL3_ENABLE)
       CONTEXT_DEFAULT_OPTIONS |= constants.SSL_OP_NO_SSLv3;
-
-    if (!binding.SSL2_ENABLE)
-      CONTEXT_DEFAULT_OPTIONS |= constants.SSL_OP_NO_SSLv2;
   }
 
   if (secureOptions === undefined) {

src/node.cc

@@ -2637,7 +2637,6 @@ static void PrintHelp() {
          "  --v8-options         print v8 command line options\n"
          "  --max-stack-size=val set max v8 stack size (bytes)\n"
 #if HAVE_OPENSSL
-         "  --enable-ssl2        enable ssl2\n"
          "  --enable-ssl3        enable ssl3\n"
 #endif
          "\n"
@@ -2675,8 +2674,9 @@ static void ParseArgs(int argc, char **argv) {
       argv[i] = const_cast<char*>("");
 #if HAVE_OPENSSL
     } else if (strcmp(arg, "--enable-ssl2") == 0) {
-      SSL2_ENABLE = true;
-      argv[i] = const_cast<char*>("");
+      fprintf(stderr,
+              "Error: --enable-ssl2 is no longer supported (CVE-2016-0800).\n");
+      exit(12);
     } else if (strcmp(arg, "--enable-ssl3") == 0) {
       SSL3_ENABLE = true;
       argv[i] = const_cast<char*>("");

src/node_crypto.cc

@@ -69,7 +69,6 @@ const char* root_certs[] = {
   NULL
 };
 
-bool SSL2_ENABLE = false;
 bool SSL3_ENABLE = false;
 
 namespace crypto {
@@ -242,23 +241,11 @@ Handle<Value> SecureContext::Init(const Arguments& args) {
     node::Utf8Value sslmethod(args[0]);
 
     if (strcmp(*sslmethod, "SSLv2_method") == 0) {
-#ifndef OPENSSL_NO_SSL2
-      method = SSLv2_method();
-#else
       return ThrowException(Exception::Error(String::New("SSLv2 methods disabled")));
-#endif
     } else if (strcmp(*sslmethod, "SSLv2_server_method") == 0) {
-#ifndef OPENSSL_NO_SSL2
-      method = SSLv2_server_method();
-#else
       return ThrowException(Exception::Error(String::New("SSLv2 methods disabled")));
-#endif
     } else if (strcmp(*sslmethod, "SSLv2_client_method") == 0) {
-#ifndef OPENSSL_NO_SSL2
-      method = SSLv2_client_method();
-#else
       return ThrowException(Exception::Error(String::New("SSLv2 methods disabled")));
-#endif
     } else if (strcmp(*sslmethod, "SSLv3_method") == 0) {
 #ifndef OPENSSL_NO_SSL3
       method = SSLv3_method();
@@ -4256,7 +4243,6 @@ void InitCrypto(Handle<Object> target) {
   ext_key_usage_symbol = NODE_PSYMBOL("ext_key_usage");
 
   NODE_DEFINE_CONSTANT(target, SSL3_ENABLE);
-  NODE_DEFINE_CONSTANT(target, SSL2_ENABLE);
 }
 
 }  // namespace crypto

src/node_crypto.h

@@ -45,7 +45,6 @@
 
 namespace node {
 
-extern bool SSL2_ENABLE;
 extern bool SSL3_ENABLE;
 
 namespace crypto {

test/external/ssl-options/test.js

@@ -11,13 +11,10 @@ var debug     = require('debug')('test-node-ssl');
 
 var common = require('../../common');
 
-var SSL2_COMPATIBLE_CIPHERS = 'RC4-MD5';
-
-var CMD_LINE_OPTIONS = [ null, "--enable-ssl2", "--enable-ssl3" ];
+var CMD_LINE_OPTIONS = [ null, "--enable-ssl3" ];
 
 var SERVER_SSL_PROTOCOLS = [
   null,
-  'SSLv2_method', 'SSLv2_server_method',
   'SSLv3_method', 'SSLv3_server_method',
   'TLSv1_method', 'TLSv1_server_method',
   'SSLv23_method','SSLv23_server_method'
@@ -25,7 +22,6 @@ var SERVER_SSL_PROTOCOLS = [
 
 var CLIENT_SSL_PROTOCOLS = [
   null,
-  'SSLv2_method', 'SSLv2_client_method',
   'SSLv3_method', 'SSLv3_client_method',
   'TLSv1_method', 'TLSv1_client_method',
   'SSLv23_method','SSLv23_client_method'
@@ -34,9 +30,7 @@ var CLIENT_SSL_PROTOCOLS = [
 var SECURE_OPTIONS = [
   null,
   0,
-  constants.SSL_OP_NO_SSLv2,
   constants.SSL_OP_NO_SSLv3,
-  constants.SSL_OP_NO_SSLv2 | constants.SSL_OP_NO_SSLv3
 ];
 
 function xtend(source) {
@@ -105,30 +99,13 @@ function isSsl3Protocol(secureProtocol) {
          secureProtocol === 'SSLv3_server_method';
 }
 
-function isSsl2Protocol(secureProtocol) {
-  assert(secureProtocol === null || typeof secureProtocol === 'string');
-
-  return secureProtocol === 'SSLv2_method' ||
-         secureProtocol === 'SSLv2_client_method' ||
-         secureProtocol === 'SSLv2_server_method';
-}
-
 function secureProtocolCompatibleWithSecureOptions(secureProtocol, secureOptions, cmdLineOption) {
   if (secureOptions == null) {
-    if (isSsl2Protocol(secureProtocol) &&
-        (!cmdLineOption || cmdLineOption.indexOf('--enable-ssl2') === -1)) {
-      return false;
-    }
-
     if (isSsl3Protocol(secureProtocol) &&
         (!cmdLineOption || cmdLineOption.indexOf('--enable-ssl3') === -1)) {
       return false;
     }
   } else {
-    if (secureOptions & constants.SSL_OP_NO_SSLv2 && isSsl2Protocol(secureProtocol)) {
-      return false;
-    }
-
     if (secureOptions & constants.SSL_OP_NO_SSLv3 && isSsl3Protocol(secureProtocol)) {
       return false;
     }
@@ -169,39 +146,10 @@ function testSetupsCompatible(serverSetup, clientSetup) {
     return false;
   }
 
-  if (isSsl2Protocol(serverSetup.secureProtocol) ||
-      isSsl2Protocol(clientSetup.secureProtocol)) {
-
-      /*
-       * It seems that in order to be able to use SSLv2, at least the server
-       * *needs* to advertise at least one cipher compatible with it.
-       */
-      if (serverSetup.ciphers !== SSL2_COMPATIBLE_CIPHERS) {
-        return false;
-      }
-
-      /*
-       * If only either one of the client or server specify SSLv2 as their
-       * protocol, then *both* of them *need* to advertise at least one cipher
-       * that is compatible with SSLv2.
-       */
-      if ((!isSsl2Protocol(serverSetup.secureProtocol) || !isSsl2Protocol(clientSetup.secureProtocol)) &&
-        (clientSetup.ciphers !== SSL2_COMPATIBLE_CIPHERS || serverSetup.ciphers !== SSL2_COMPATIBLE_CIPHERS)) {
-        return false;
-      }
-  }
-
   return true;
 }
 
 function sslSetupMakesSense(cmdLineOption, secureProtocol, secureOption) {
-  if (isSsl2Protocol(secureProtocol)) {
-    if (secureOption & constants.SSL_OP_NO_SSLv2 ||
-        (secureOption == null && (!cmdLineOption || cmdLineOption.indexOf('--enable-ssl2') === -1))) {
-      return false;
-    }
-  }
-
   if (isSsl3Protocol(secureProtocol)) {
     if (secureOption & constants.SSL_OP_NO_SSLv3 ||
         (secureOption == null && (!cmdLineOption || cmdLineOption.indexOf('--enable-ssl3') === -1))) {
@@ -230,12 +178,6 @@ function createTestsSetups() {
           };
 
           serversSetup.push(serverSetup);
-
-          if (isSsl2Protocol(serverSecureProtocol)) {
-            var setupWithSsl2Ciphers = xtend(serverSetup);
-            setupWithSsl2Ciphers.ciphers = SSL2_COMPATIBLE_CIPHERS;
-            serversSetup.push(setupWithSsl2Ciphers);
-          }
         }
       });
     });
@@ -252,12 +194,6 @@ function createTestsSetups() {
           };
 
           clientsSetup.push(clientSetup);
-
-          if (isSsl2Protocol(clientSecureProtocol)) {
-            var setupWithSsl2Ciphers = xtend(clientSetup);
-            setupWithSsl2Ciphers.ciphers = SSL2_COMPATIBLE_CIPHERS;
-            clientsSetup.push(setupWithSsl2Ciphers);
-          }
         }
       });
     });
@@ -367,10 +303,6 @@ function stringToSecureOptions(secureOptionsString) {
 
   var optionStrings = secureOptionsString.split('|');
   optionStrings.forEach(function (option) {
-    if (option === 'SSL_OP_NO_SSLv2') {
-      secureOptions |= constants.SSL_OP_NO_SSLv2;
-    }
-
     if (option === 'SSL_OP_NO_SSLv3') {
       secureOptions |= constants.SSL_OP_NO_SSLv3;
     }
@@ -430,10 +362,6 @@ function checkTestExitCode(testSetup, serverExitCode, clientExitCode) {
 function secureOptionsToString(secureOptions) {
   var secureOptsString = '';
 
-  if (secureOptions & constants.SSL_OP_NO_SSLv2) {
-    secureOptsString += 'SSL_OP_NO_SSLv2';
-  }
-
   if (secureOptions & constants.SSL_OP_NO_SSLv3) {
     secureOptsString += '|SSL_OP_NO_SSLv3';
   }

test/simple/test-tls-enable-ssl2.js

@@ -0,0 +1,21 @@
+'use strict';
+
+var common = require('../common');
+var assert = require('assert');
+var spawn = require('child_process').spawn;
+
+var stdout = '';
+var stderr = '';
+var proc = spawn(process.execPath, ['--enable-ssl2', '-e', '0']);
+proc.stdout.setEncoding('utf8');
+proc.stderr.setEncoding('utf8');
+proc.stdout.on('data', function(data) { stdout += data; });
+proc.stderr.on('data', function(data) { stderr += data; });
+proc.on('exit', common.mustCall(function(exitCode, signalCode) {
+  assert.strictEqual(exitCode, 12);
+  assert.strictEqual(signalCode, null);
+}));
+process.on('exit', function() {
+  assert.strictEqual(stdout, '');
+  assert(/Error: --enable-ssl2 is no longer supported/.test(stderr));
+});

test/simple/test-tls-ssl2-methods.js

@@ -0,0 +1,19 @@
+'use strict';
+
+var common = require('../common');
+var assert = require('assert');
+
+try {
+  var crypto = require('crypto');
+} catch (e) {
+  console.log('1..0 # Skipped: missing crypto');
+  return;
+}
+
+var methods = ['SSLv2_method', 'SSLv2_client_method', 'SSLv2_server_method'];
+
+methods.forEach(function(method) {
+  assert.throws(function() {
+    crypto.createCredentials({ secureProtocol: method });
+  }, /SSLv2 methods disabled/);
+});