data-fetcher: Discard really big data URLs.

mojo/fetcher/data_fetcher.cc

 // Copyright 2015 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 "mojo/fetcher/data_fetcher.h"
 
 #include "base/bind.h"
 #include "base/files/file_path.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/thread_task_runner_handle.h"
 #include "net/base/data_url.h"
 #include "third_party/mojo/src/mojo/public/cpp/system/data_pipe.h"
 
 namespace mojo {
 namespace fetcher {
 
 ScopedDataPipeConsumerHandle CreateConsumerHandleForString(
     const std::string& data) {
+  if (data.size() > std::numeric_limits<uint32_t>::max())
+    return ScopedDataPipeConsumerHandle();
   uint32_t num_bytes = static_cast<uint32_t>(data.size());
   MojoCreateDataPipeOptions options;
   options.struct_size = sizeof(MojoCreateDataPipeOptions);
   options.flags = MOJO_CREATE_DATA_PIPE_OPTIONS_FLAG_NONE;
   options.element_num_bytes = 1;
   options.capacity_num_bytes = num_bytes;
   mojo::DataPipe data_pipe(options);
   MojoResult result =
       WriteDataRaw(data_pipe.producer_handle.get(), data.data(), &num_bytes,
                    MOJO_WRITE_DATA_FLAG_ALL_OR_NONE);
@@ skipping 73 matching lines @@
 bool DataFetcher::PeekFirstLine(std::string* line) {
   // This is only called for 'mojo magic' (i.e. detecting shebang'ed
   // content-handler. Since HasMojoMagic() returns false above, this should
   // never be reached.
   NOTREACHED();
   return false;
 }
 
 }  // namespace fetcher
 }  // namespace mojo