Limit QUIC uncompressed header size per stream to 16K, by default. Protected by FLAGS_quic_limit_un…

net/quic/core/quic_header_list.cc

 // Copyright (c) 2016 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_header_list.h"
 
 using std::string;
 
+#include "net/quic/core/quic_flags.h"
+#include "net/quic/core/quic_protocol.h"
+
 namespace net {
 
-QuicHeaderList::QuicHeaderList() : uncompressed_header_bytes_(0) {}
+QuicHeaderList::QuicHeaderList()
+    : max_uncompressed_header_bytes_(kDefaultMaxUncompressedHeaderSize),
+      uncompressed_header_bytes_(0) {}
 
 QuicHeaderList::QuicHeaderList(QuicHeaderList&& other) = default;
 
 QuicHeaderList::QuicHeaderList(const QuicHeaderList& other) = default;
 
 QuicHeaderList& QuicHeaderList::operator=(const QuicHeaderList& other) =
     default;
 
 QuicHeaderList& QuicHeaderList::operator=(QuicHeaderList&& other) = default;
 
 QuicHeaderList::~QuicHeaderList() {}
 
 void QuicHeaderList::OnHeaderBlockStart() {
   QUIC_BUG_IF(uncompressed_header_bytes_ != 0)
       << "OnHeaderBlockStart called more than once!";
 }
 
 void QuicHeaderList::OnHeader(base::StringPiece name, base::StringPiece value) {
-  header_list_.emplace_back(name.as_string(), value.as_string());
+  // Avoid infinte buffering of headers. No longer store headers
+  // once the current headers are over the limit.
+  if (!FLAGS_quic_limit_uncompressed_headers ||
+      uncompressed_header_bytes_ == 0 || !header_list_.empty()) {
+    header_list_.emplace_back(name.as_string(), value.as_string());
+  }
 }
 
 void QuicHeaderList::OnHeaderBlockEnd(size_t uncompressed_header_bytes) {
-  uncompressed_header_bytes_ = uncompressed_header_bytes;
-  compressed_header_bytes_ = uncompressed_header_bytes;
+  OnHeaderBlockEnd(uncompressed_header_bytes, uncompressed_header_bytes);
 }
 
 void QuicHeaderList::OnHeaderBlockEnd(size_t uncompressed_header_bytes,
                                       size_t compressed_header_bytes) {
   uncompressed_header_bytes_ = uncompressed_header_bytes;
   compressed_header_bytes_ = compressed_header_bytes;
+  if (FLAGS_quic_limit_uncompressed_headers &&
+      uncompressed_header_bytes_ > max_uncompressed_header_bytes_) {
+    Clear();
+  }
 }
 
 void QuicHeaderList::Clear() {
   header_list_.clear();
   uncompressed_header_bytes_ = 0;
 }
 
 string QuicHeaderList::DebugString() const {
   string s = "{ ";
   for (const auto& p : *this) {
     s.append(p.first + "=" + p.second + ", ");
   }
   s.append("}");
   return s;
 }
 
 }  // namespace net