build,src: remove sslv3 support

SSLv3 is susceptible to downgrade attacks.  Provide secure defaults,
disable v3 protocol support entirely.

PR-URL: https://github.com/iojs/io.js/pull/315
Reviewed-By: Fedor Indutny <fedor@indutny.com>
Reviewed-By: Trevor Norris <trev.norris@gmail.com>

2 files changed, 10 insertions, 14 deletions

diff --git a/src/node_crypto.cc b/src/node_crypto.cc
index 26ac54bf36..c088fe25db 100644
--- a/src/node_crypto.cc
+++ b/src/node_crypto.cc
@@ -288,6 +288,10 @@ void SecureContext::Init(const FunctionCallbackInfo<Value>& args) {
   if (args.Length() == 1 && args[0]->IsString()) {
     const node::Utf8Value sslmethod(env->isolate(), args[0]);
 
+    // Note that SSLv2 and SSLv3 are disallowed but SSLv2_method and friends
+    // are still accepted.  They are OpenSSL's way of saying that all known
+    // protocols are supported unless explicitly disabled (which we do below
+    // for SSLv2 and SSLv3.)
     if (strcmp(*sslmethod, "SSLv2_method") == 0) {
       return env->ThrowError("SSLv2 methods disabled");
     } else if (strcmp(*sslmethod, "SSLv2_server_method") == 0) {
@@ -295,23 +299,11 @@ void SecureContext::Init(const FunctionCallbackInfo<Value>& args) {
     } else if (strcmp(*sslmethod, "SSLv2_client_method") == 0) {
       return env->ThrowError("SSLv2 methods disabled");
     } else if (strcmp(*sslmethod, "SSLv3_method") == 0) {
-#ifndef OPENSSL_NO_SSL3
-      method = SSLv3_method();
-#else
       return env->ThrowError("SSLv3 methods disabled");
-#endif
     } else if (strcmp(*sslmethod, "SSLv3_server_method") == 0) {
-#ifndef OPENSSL_NO_SSL3
-      method = SSLv3_server_method();
-#else
       return env->ThrowError("SSLv3 methods disabled");
-#endif
     } else if (strcmp(*sslmethod, "SSLv3_client_method") == 0) {
-#ifndef OPENSSL_NO_SSL3
-      method = SSLv3_client_method();
-#else
       return env->ThrowError("SSLv3 methods disabled");
-#endif
     } else if (strcmp(*sslmethod, "SSLv23_method") == 0) {
       method = SSLv23_method();
     } else if (strcmp(*sslmethod, "SSLv23_server_method") == 0) {
@@ -346,7 +338,9 @@ void SecureContext::Init(const FunctionCallbackInfo<Value>& args) {
   // Disable SSLv2 in the case when method == SSLv23_method() and the
   // cipher list contains SSLv2 ciphers (not the default, should be rare.)
   // The bundled OpenSSL doesn't have SSLv2 support but the system OpenSSL may.
+  // SSLv3 is disabled because it's susceptible to downgrade attacks (POODLE.)
   SSL_CTX_set_options(sc->ctx_, SSL_OP_NO_SSLv2);
+  SSL_CTX_set_options(sc->ctx_, SSL_OP_NO_SSLv3);
 
   // SSL session cache configuration
   SSL_CTX_set_session_cache_mode(sc->ctx_,
diff --git a/src/node_crypto_clienthello.cc b/src/node_crypto_clienthello.cc
index 34507858c9..8fbc3161f8 100644
--- a/src/node_crypto_clienthello.cc
+++ b/src/node_crypto_clienthello.cc
@@ -61,13 +61,15 @@ void ClientHelloParser::ParseHeader(const uint8_t* data, size_t avail) {
 
   // Check hello protocol version.  Protocol tuples that we know about:
   //
-  // (3,0) SSL v3.0
   // (3,1) TLS v1.0
   // (3,2) TLS v1.1
   // (3,3) TLS v1.2
   //
-  if (data[body_offset_ + 4] != 0x03 || data[body_offset_ + 5] > 0x03)
+  if (data[body_offset_ + 4] != 0x03 ||
+      data[body_offset_ + 5] < 0x01 ||
+      data[body_offset_ + 5] > 0x03) {
     goto fail;
+  }
 
   if (data[body_offset_] == kClientHello) {
     if (state_ == kTLSHeader) {