Cleanup some PPAPI proxy code.

ppapi/proxy/pdf_resource.cc

 // Copyright (c) 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 "ppapi/proxy/pdf_resource.h"
 
 #include <stdlib.h>
 #include <string.h>
 
 #include "base/command_line.h"
@@ skipping 80 matching lines @@
   while (match_start != USEARCH_DONE) {
     int32_t matched_length = usearch_getMatchedLength(searcher);
     PP_PrivateFindResult result;
     result.start_index = match_start;
     result.length = matched_length;
     pp_results.push_back(result);
     match_start = usearch_next(searcher, &status);
     DCHECK(status == U_ZERO_ERROR);
   }
 
-  *count = static_cast<uint32_t>(pp_results.size());
-  if (*count) {
-    *results = reinterpret_cast<PP_PrivateFindResult*>(malloc(
-        *count * sizeof(PP_PrivateFindResult)));
-    memcpy(*results, &pp_results[0], *count * sizeof(PP_PrivateFindResult));
+  if (pp_results.empty() ||
+      pp_results.size() > std::numeric_limits<uint32_t>::max() ||
+      pp_results.size() >
+          std::numeric_limits<size_t>::max() / sizeof(PP_PrivateFindResult)) {

[raymes, 2015/05/20 00:26:48]

Would it be simpler just to have some large constant maximum?

kMaxNumSearchResults = 1000000;

[Lei Zhang, 2015/05/20 00:30:48]

I can replace std::numeric_limits<size_t>::max() with SIZE_MAX. That'll make it
less verbose.

[Lei Zhang, 2015/05/20 00:46:34]

Done in patch set 3. But in general, the security folks do these kinds of
checks, or use base/numerics/safe_conversions.h and friends all the time, rather
than set some arbitrary limit. The user's machine may run out of memory, but
that's not my concern.

+    *count = 0;
+    *results = nullptr;
   } else {
-    *results = NULL;
+    *count = static_cast<uint32_t>(pp_results.size());
+    const size_t result_size = pp_results.size() * sizeof(PP_PrivateFindResult);
+    *results = reinterpret_cast<PP_PrivateFindResult*>(malloc(result_size));
+    memcpy(*results, &pp_results[0], result_size);
   }
 
   usearch_close(searcher);
 }
 
 void PDFResource::DidStartLoading() {
   Post(RENDERER, PpapiHostMsg_PDF_DidStartLoading());
 }
 
 void PDFResource::DidStopLoading() {
@@ skipping 91 matching lines @@
 void PDFResource::GetV8ExternalSnapshotData(const char** natives_data_out,
                                             int* natives_size_out,
                                             const char** snapshot_data_out,
                                             int* snapshot_size_out) {
   gin::V8Initializer::GetV8ExternalSnapshotData(
       natives_data_out, natives_size_out, snapshot_data_out, snapshot_size_out);
 }
 
 }  // namespace proxy
 }  // namespace ppapi