Add a LOG(DFATAL) if the sequence number length is too small to fit the

net/quic/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/quic_framer.h"
 
 #include "base/containers/hash_tables.h"
 #include "base/stl_util.h"
 #include "net/quic/crypto/crypto_framer.h"
 #include "net/quic/crypto/crypto_handshake_message.h"
@@ skipping 2031 matching lines @@
 
   // TODO(satyamshekhar): Decide how often we really should send this
   // entropy_hash update.
   if (!writer->WriteUInt8(frame.sent_info.entropy_hash)) {
     return false;
   }
 
   DCHECK_GE(header.packet_sequence_number, frame.sent_info.least_unacked);
   const QuicPacketSequenceNumber least_unacked_delta =
       header.packet_sequence_number - frame.sent_info.least_unacked;
+  const QuicPacketSequenceNumber length_shift =
+      header.public_header.sequence_number_length * 8;
+  if (least_unacked_delta >> length_shift > 0) {
+    LOG(DFATAL) << "sequence_number_length "
+                << header.public_header.sequence_number_length
+                << " is too small for least_unacked_delta: "
+                << least_unacked_delta;
+    return false;
+  }
   if (!AppendPacketSequenceNumber(header.public_header.sequence_number_length,
                                   least_unacked_delta, writer)) {
     return false;
   }
 
   const ReceivedPacketInfo& received_info = frame.received_info;
   QuicPacketEntropyHash ack_entropy_hash = received_info.entropy_hash;
   NackRangeMap::reverse_iterator ack_iter = ack_info.nack_ranges.rbegin();
   if (truncated) {
     // Skip the nack ranges which the truncated ack won't include and set
@@ skipping 260 matching lines @@
 
 bool QuicFramer::RaiseError(QuicErrorCode error) {
   DVLOG(1) << "Error detail: " << detailed_error_;
   set_error(error);
   visitor_->OnError(this);
   reader_.reset(NULL);
   return false;
 }
 
 }  // namespace net