add ECDHE support

lib/crypto.js

@@ -90,6 +90,9 @@ exports.createCredentials = function(options, context) {
 
   if (context) return c;
 
+  if (options.ecdheCurves)
+    c.context.setECDHECurves.apply(c.context, options.ecdheCurves);
+
   if (options.key) {
     if (options.passphrase) {
       c.context.setKey(options.key, options.passphrase);

lib/tls.js

@@ -1109,6 +1109,7 @@ function Server(/* [options], listener */) {
     cert: self.cert,
     ca: self.ca,
     ciphers: self.ciphers || DEFAULT_CIPHERS,
+    ecdheCurves: self.ecdheCurves,
     secureProtocol: self.secureProtocol,
     secureOptions: self.secureOptions,
     crl: self.crl,
@@ -1197,6 +1198,7 @@ Server.prototype.setOptions = function(options) {
   if (options.secureProtocol) this.secureProtocol = options.secureProtocol;
   if (options.crl) this.crl = options.crl;
   if (options.ciphers) this.ciphers = options.ciphers;
+  if (options.ecdheCurves) this.ecdheCurves = options.ecdheCurves;
   var secureOptions = options.secureOptions || 0;
   if (options.honorCipherOrder) {
     secureOptions |= constants.SSL_OP_CIPHER_SERVER_PREFERENCE;

src/node_crypto.cc

@@ -131,6 +131,10 @@ void SecureContext::Initialize(Handle<Object> target) {
   t->SetClassName(String::NewSymbol("SecureContext"));
 
   NODE_SET_PROTOTYPE_METHOD(t, "init", SecureContext::Init);
+  NODE_SET_PROTOTYPE_METHOD(t, "setECDHECurves",
+                               SecureContext::SetECDHECurves);
+  NODE_SET_PROTOTYPE_METHOD(t, "clearECDHECurves",
+                               SecureContext::ClearECDHECurves);
   NODE_SET_PROTOTYPE_METHOD(t, "setKey", SecureContext::SetKey);
   NODE_SET_PROTOTYPE_METHOD(t, "setCert", SecureContext::SetCert);
   NODE_SET_PROTOTYPE_METHOD(t, "addCACert", SecureContext::AddCACert);
@@ -220,6 +224,8 @@ Handle<Value> SecureContext::Init(const Arguments& args) {
 
   sc->ctx_ = SSL_CTX_new(method);
 
+  SSL_CTX_set_app_data(sc->ctx_, sc);
+
   // SSL session cache configuration
   SSL_CTX_set_session_cache_mode(sc->ctx_,
                                  SSL_SESS_CACHE_SERVER |
@@ -232,6 +238,100 @@ Handle<Value> SecureContext::Init(const Arguments& args) {
   return True();
 }
 
+static EC_KEY *SecureContext_ecdhe_key_cb(SSL *ssl, int is_ex, int bit_len) {
+  SecureContext *sc = (SecureContext *)SSL_CTX_get_app_data(SSL_get_SSL_CTX(ssl));
+
+  assert(NULL != sc->ecdhe_keys);
+
+  for (int i = 0; i < sc->ecdhe_keys_len; i++)
+    if (sc->ecdhe_keys[i].bit_len >= bit_len)
+      return sc->ecdhe_keys[i].key;
+
+  if (0 < sc->ecdhe_keys_len)
+    return sc->ecdhe_keys[sc->ecdhe_keys_len - 1].key;
+
+  return NULL;
+}
+
+Handle<Value> SecureContext::SetECDHECurves(const Arguments& args) {
+  HandleScope scope;
+
+  SecureContext *sc = ObjectWrap::Unwrap<SecureContext>(args.Holder());
+  sc->_ClearECDHECurves();
+
+  char err[80];
+  int i = 0;
+
+  sc->ecdhe_keys_len = args.Length();
+  sc->ecdhe_keys = new BitLenKey<EC_KEY>[sc->ecdhe_keys_len];
+
+  for (; i < args.Length(); i++) {
+    String::Utf8Value _curvesn(args[i]);
+    const char *curvesn = *_curvesn;
+
+    int curvenid = OBJ_sn2nid(curvesn);
+    if (NID_undef == curvenid) {
+      snprintf(err, 80, "Invalid curve: %s", curvesn);
+      goto err_obj_sn2nid;
+    }
+
+    EC_KEY *key = EC_KEY_new_by_curve_name(curvenid);
+    if (NULL == key) {
+      snprintf(err, 80, "Failed to generate key for curve: %s", curvesn);
+      goto err_ec_key_new;
+    }
+
+    const EC_GROUP *grp = EC_KEY_get0_group(key);
+    if (NULL == grp) {
+      snprintf(err, 80, "Failed to get group for curve: %s", curvesn);
+      goto err_ec_key_get_group;
+    }
+
+    sc->ecdhe_keys[i].bit_len = EC_GROUP_get_degree(grp);
+    sc->ecdhe_keys[i].key = key;
+  }
+
+  SSL_CTX_set_tmp_ecdh_callback(sc->ctx_, SecureContext_ecdhe_key_cb);
+
+  return True();
+
+err_obj_sn2nid:
+err_ec_key_new:
+  i--;
+
+err_ec_key_get_group:
+  for (; i >= 0; i--)
+    EC_KEY_free(sc->ecdhe_keys[i].key);
+
+  delete sc->ecdhe_keys;
+  sc->ecdhe_keys = NULL;
+
+  return ThrowException(Exception::Error(String::New(err)));
+}
+
+Handle<Value> SecureContext::ClearECDHECurves(const Arguments& args) {
+  HandleScope scope;
+
+  SecureContext *sc = ObjectWrap::Unwrap<SecureContext>(args.Holder());
+
+  sc->_ClearECDHECurves();
+
+  return True();
+}
+
+void SecureContext::_ClearECDHECurves(void) {
+  if (NULL == ecdhe_keys)
+    return;
+
+  for (int i = 0; i < ecdhe_keys_len; i++)
+    EC_KEY_free(ecdhe_keys[i].key);
+
+  delete ecdhe_keys;
+  ecdhe_keys = NULL;
+
+  SSL_CTX_set_tmp_ecdh_callback(ctx_, NULL);
+}
+
 
 SSL_SESSION* SecureContext::GetSessionCallback(SSL* s,
                                                unsigned char* key,

src/node_crypto.h

@@ -27,6 +27,7 @@
 #include "node_object_wrap.h"
 #include "v8.h"
 
+#include <openssl/objects.h>
 #include <openssl/ssl.h>
 #include <openssl/err.h>
 #include <openssl/evp.h>
@@ -52,6 +53,11 @@ static X509_STORE* root_cert_store;
 // Forward declaration
 class Connection;
 
+template <typename KeyType> struct BitLenKey {
+  int bit_len;
+  KeyType *key;
+};
+
 class SecureContext : ObjectWrap {
  public:
   static void Initialize(v8::Handle<v8::Object> target);
@@ -60,11 +66,16 @@ class SecureContext : ObjectWrap {
   // TODO: ca_store_ should probably be removed, it's not used anywhere.
   X509_STORE *ca_store_;
 
+  int ecdhe_keys_len;
+  BitLenKey<EC_KEY> *ecdhe_keys;
+
  protected:
   static const int kMaxSessionSize = 10 * 1024;
 
   static v8::Handle<v8::Value> New(const v8::Arguments& args);
   static v8::Handle<v8::Value> Init(const v8::Arguments& args);
+  static v8::Handle<v8::Value> SetECDHECurves(const v8::Arguments& args);
+  static v8::Handle<v8::Value> ClearECDHECurves(const v8::Arguments& args);
   static v8::Handle<v8::Value> SetKey(const v8::Arguments& args);
   static v8::Handle<v8::Value> SetCert(const v8::Arguments& args);
   static v8::Handle<v8::Value> AddCACert(const v8::Arguments& args);
@@ -85,8 +96,11 @@ class SecureContext : ObjectWrap {
   SecureContext() : ObjectWrap() {
     ctx_ = NULL;
     ca_store_ = NULL;
+    ecdhe_keys = NULL;
   }
 
+  void _ClearECDHECurves(void);
+
   void FreeCTXMem() {
     if (ctx_) {
       if (ctx_->cert_store == root_cert_store) {
@@ -106,6 +120,7 @@ class SecureContext : ObjectWrap {
 
   ~SecureContext() {
     FreeCTXMem();
+    _ClearECDHECurves();
   }
 
  private: