Make the VER tag required in QUIC CHLO and SHLO messages.

net/quic/crypto/quic_crypto_server_config.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/quic/crypto/quic_crypto_server_config.h"
 
 #include <stdlib.h>
 #include <algorithm>
 
 #include "base/stl_util.h"
@@ skipping 466 matching lines @@
 
   const CryptoHandshakeMessage& client_hello =
       validate_chlo_result.client_hello;
   const ClientHelloInfo& info = validate_chlo_result.info;
 
   // If the client's preferred version is not the version we are currently
   // speaking, then the client went through a version negotiation.  In this
   // case, we need to make sure that we actually do not support this version
   // and that it wasn't a downgrade attack.
   QuicTag client_version_tag;
-  // TODO(rch): Make this check mandatory when we remove QUIC_VERSION_12.
-  if (client_hello.GetUint32(kVER, &client_version_tag) == QUIC_NO_ERROR) {
-    QuicVersion client_version = QuicTagToQuicVersion(client_version_tag);
-    if (client_version != version) {
-      // Just because client_version is a valid version enum doesn't mean that
-      // this server actually supports that version, so we check to see if
-      // it's actually in the supported versions list.
-      for (size_t i = 0; i < supported_versions.size(); ++i) {
-        if (client_version == supported_versions[i]) {
-          *error_details = "Downgrade attack detected";
-          return QUIC_VERSION_NEGOTIATION_MISMATCH;
-        }
+  if (client_hello.GetUint32(kVER, &client_version_tag) != QUIC_NO_ERROR) {
+    *error_details = "client hello missing version list";
+    return QUIC_INVALID_CRYPTO_MESSAGE_PARAMETER;
+  }
+  QuicVersion client_version = QuicTagToQuicVersion(client_version_tag);
+  if (client_version != version) {
+    // Just because client_version is a valid version enum doesn't mean that
+    // this server actually supports that version, so we check to see if
+    // it's actually in the supported versions list.
+    for (size_t i = 0; i < supported_versions.size(); ++i) {
+      if (client_version == supported_versions[i]) {
+        *error_details = "Downgrade attack detected";
+        return QUIC_VERSION_NEGOTIATION_MISMATCH;
       }
     }
   }
 
   StringPiece requested_scid;
   client_hello.GetStringPiece(kSCID, &requested_scid);
   const QuicWallTime now(clock->WallNow());
 
   scoped_refptr<Config> requested_config;
   scoped_refptr<Config> primary_config;
@@ skipping 816 matching lines @@
 
 QuicCryptoServerConfig::Config::Config()
     : channel_id_enabled(false),
       is_primary(false),
       primary_time(QuicWallTime::Zero()),
       priority(0) {}
 
 QuicCryptoServerConfig::Config::~Config() { STLDeleteElements(&key_exchanges); }
 
 }  // namespace net