Pepper: Fix crash on allocation failure.

GetPNaClResourceInfo() currently performs a 1 megabyte allocation. Though any
memory allocation can fail, this one is more likely due to its size.

This change mitigates this problem in two ways. If memory allocation fails, we
report an error and return early instead of using memory.

Additionally, this change checks the size of the file before performing a
memory allocation. This should lead to smaller allocations and more successful
plugin loads.

BUG=370965

Review URL: https://codereview.chromium.org/274673002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@269791 0039d316-1c4b-4281-b951-d872f2087c98

components/nacl/renderer/ppb_nacl_private_impl.cc

@@ -1114,16 +1114,38 @@ 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) {
+    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;