Drop Packets with the multipath bit set before decryption. Protected by FLAGS_quic_reloadable_flag_…

net/quic/core/quic_framer.cc

 // Copyright (c) 2012 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/core/quic_framer.h"
 
 #include <cstdint>
 #include <memory>
 
 #include "base/compiler_specific.h"
@@ skipping 766 matching lines @@
     return false;
   }
 
   public_header->multipath_flag =
       (public_flags & PACKET_PUBLIC_FLAGS_MULTIPATH) != 0;
   public_header->reset_flag = (public_flags & PACKET_PUBLIC_FLAGS_RST) != 0;
   public_header->version_flag =
       (public_flags & PACKET_PUBLIC_FLAGS_VERSION) != 0;
 
   if (validate_flags_ && !public_header->version_flag &&
-      public_flags > PACKET_PUBLIC_FLAGS_MAX) {
+      public_flags > (FLAGS_quic_reloadable_flag_quic_remove_multipath_bit
+                          ? PACKET_PUBLIC_FLAGS_MAX_WITHOUT_MULTIPATH_FLAG
+                          : PACKET_PUBLIC_FLAGS_MAX)) {
     set_detailed_error("Illegal public flags value.");
     return false;
   }
 
   if (public_header->reset_flag && public_header->version_flag) {
     set_detailed_error("Got version flag in reset packet");
     return false;
   }
 
   switch (public_flags & PACKET_PUBLIC_FLAGS_8BYTE_CONNECTION_ID) {
@@ skipping 20 matching lines @@
     if (!reader->ReadUInt32(&version_tag)) {
       set_detailed_error("Unable to read protocol version.");
       return false;
     }
 
     // If the version from the new packet is the same as the version of this
     // framer, then the public flags should be set to something we understand.
     // If not, this raises an error.
     last_version_tag_ = version_tag;
     QuicVersion version = QuicTagToQuicVersion(version_tag);
-    if (version == quic_version_ && public_flags > PACKET_PUBLIC_FLAGS_MAX) {
+    if (version == quic_version_ &&
+        public_flags > (FLAGS_quic_reloadable_flag_quic_remove_multipath_bit
+                            ? PACKET_PUBLIC_FLAGS_MAX_WITHOUT_MULTIPATH_FLAG
+                            : PACKET_PUBLIC_FLAGS_MAX)) {
       set_detailed_error("Illegal public flags value.");
       return false;
     }
     public_header->versions.push_back(version);
   }
 
   // A nonce should only be present in packets from the server to the client,
   // which are neither version negotiation nor public reset packets.
   if (public_flags & PACKET_PUBLIC_FLAGS_NONCE &&
       !(public_flags & PACKET_PUBLIC_FLAGS_VERSION) &&
@@ skipping 1306 matching lines @@
 
 bool QuicFramer::RaiseError(QuicErrorCode error) {
   QUIC_DLOG(INFO) << ENDPOINT << "Error: " << QuicErrorCodeToString(error)
                   << " detail: " << detailed_error_;
   set_error(error);
   visitor_->OnError(this);
   return false;
 }
 
 }  // namespace net