Pepper: Fix crash on allocation failure.

components/nacl/renderer/ppb_nacl_private_impl.cc

Index: components/nacl/renderer/ppb_nacl_private_impl.cc
diff --git a/components/nacl/renderer/ppb_nacl_private_impl.cc b/components/nacl/renderer/ppb_nacl_private_impl.cc
index 3361f61783c86f485bdf6ae9bcb5224e1ec5a44a..f3c87f27777042bda54f97baddc6f40b0d7de3b7 100644
--- a/components/nacl/renderer/ppb_nacl_private_impl.cc
+++ b/components/nacl/renderer/ppb_nacl_private_impl.cc
@@ -1136,16 +1136,38 @@ PP_Bool GetPNaClResourceInfo(PP_Instance instance,
     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;