Use an alternate mechanism for CreateFile calls in Chrome

base/win/iat_patch_function.cc

 // Copyright (c) 2011 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 "base/win/iat_patch_function.h"
 
 #include "base/logging.h"
 #include "base/win/pe_image.h"
 
 namespace base {
@@ skipping 38 matching lines @@
 // length                 Number of bytes to copy
 //
 // Returns: Windows error code (winerror.h). NO_ERROR if successful
 DWORD ModifyCode(void* old_code, void* new_code, int length) {
   if ((NULL == old_code) || (NULL == new_code) || (0 == length)) {
     NOTREACHED();
     return ERROR_INVALID_PARAMETER;
   }
 
   // Change the page protection so that we can write.
+  MEMORY_BASIC_INFORMATION memory_info;
   DWORD error = NO_ERROR;
   DWORD old_page_protection = 0;
+
+  if (!::VirtualQuery(old_code, &memory_info, sizeof(memory_info))) {
+    error = GetLastError();
+    NOTREACHED();

[rvargas (doing something else), 2014/01/21 21:19:49]

On second thoughts, we should probably just remove this notreached (and the one
below). I don't think they are really useful.

[Cait (Slow), 2014/01/21 21:47:19]

Done.

+    return error;
+  }
+
+  DWORD is_executable = (PAGE_EXECUTE | PAGE_EXECUTE_READ |
+                         PAGE_EXECUTE_READWRITE | PAGE_EXECUTE_WRITECOPY) &
+                         memory_info.Protect;

[rvargas (doing something else), 2014/01/21 20:03:26]

tiny nit: one less space here.

[Cait (Slow), 2014/01/21 21:47:19]

Done.

+
   if (VirtualProtect(old_code,
                      length,
-                     PAGE_READWRITE,
+                     is_executable ? PAGE_EXECUTE_READWRITE :
+                                     PAGE_READWRITE,
                      &old_page_protection)) {
 
     // Write the data.
     CopyMemory(old_code, new_code, length);
 
     // Restore the old page protection.
     error = ERROR_SUCCESS;
     VirtualProtect(old_code,
                   length,
                   old_page_protection,
@@ skipping 195 matching lines @@
   module_handle_ = NULL;
   intercept_function_ = NULL;
   original_function_ = NULL;
   iat_thunk_ = NULL;
 
   return error;
 }
 
 }  // namespace win
 }  // namespace base