Pepper: Fix crash on allocation failure.

components/nacl/renderer/ppb_nacl_private_impl.cc

 // Copyright 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 "components/nacl/renderer/ppb_nacl_private_impl.h"
 
 #include <numeric>
 #include <string>
 #include <vector>
 
@@ skipping 1118 matching lines @@
   base::PlatformFile file = GetReadonlyPnaclFD(filename);
   if (file == base::kInvalidPlatformFileValue) {
     load_manager->ReportLoadError(
         PP_NACL_ERROR_PNACL_RESOURCE_FETCH,
         "The Portable Native Client (pnacl) component is not "
         "installed. Please consult chrome://components for more "
         "information.");
     return PP_FALSE;
   }
 
-  const int kBufferSize = 1 << 20;
-  scoped_ptr<char[]> buffer(new char[kBufferSize]);
-  if (base::ReadPlatformFile(file, 0, buffer.get(), kBufferSize) < 0) {
+  base::PlatformFileInfo file_info;
+  if (!GetPlatformFileInfo(file, &file_info)) {
     load_manager->ReportLoadError(
         PP_NACL_ERROR_PNACL_RESOURCE_FETCH,
-        std::string("PnaclResources::ReadResourceInfo reading failed for: ") +
+        std::string("GetPNaClResourceInfo, GetFileInfo failed for: ") +
             filename);
     return PP_FALSE;
   }
 
+  if (file_info.size > 1 << 20) {

[bbudge, 2014/05/08 00:15:59]

The old behavior seems bad since it would only do a partial read if the resource
was bigger than the limit, and if the memory was successfully allocated there
wouldn't be any error notification.

This seems much better, but why not just try to allocate the whole file size,
and return failure only when the allocation failed (when buffer.get() == NULL)?

+    load_manager->ReportLoadError(
+        PP_NACL_ERROR_PNACL_RESOURCE_FETCH,
+        std::string("GetPNaClResourceInfo, file too large: ") + filename);
+    return PP_FALSE;
+  }
+
+  scoped_ptr<char[]> buffer(new char[file_info.size]);
+  if (buffer.get() == NULL) {
+    load_manager->ReportLoadError(
+        PP_NACL_ERROR_PNACL_RESOURCE_FETCH,
+        std::string("GetPNaClResourceInfo, couldn't allocate for: ") +
+            filename);
+    return PP_FALSE;
+  }
+
+  if (base::ReadPlatformFile(file, 0, buffer.get(), file_info.size) < 0) {
+    load_manager->ReportLoadError(
+        PP_NACL_ERROR_PNACL_RESOURCE_FETCH,
+        std::string("GetPNaClResourceInfo, reading failed for: ") + filename);
+    return PP_FALSE;
+  }
+
   // Expect the JSON file to contain a top-level object (dictionary).
   Json::Reader json_reader;
   Json::Value json_data;
   if (!json_reader.parse(buffer.get(), json_data)) {
     load_manager->ReportLoadError(
         PP_NACL_ERROR_PNACL_RESOURCE_FETCH,
         std::string("Parsing resource info failed: JSON parse error: ") +
             json_reader.getFormattedErrorMessages());
     return PP_FALSE;
   }
@@ skipping 122 matching lines @@
   &GetCpuFeatureAttrs
 };
 
 }  // namespace
 
 const PPB_NaCl_Private* GetNaClPrivateInterface() {
   return &nacl_interface;
 }
 
 }  // namespace nacl