Adding the VerifyModule function (and helpers) to safe browsing.

chrome/browser/safe_browsing/verifier.cc

Index: chrome/browser/safe_browsing/verifier.cc
diff --git a/chrome/browser/safe_browsing/verifier.cc b/chrome/browser/safe_browsing/verifier.cc
deleted file mode 100644
index b3416756632344b0b8bd18931750163532b9d75b..0000000000000000000000000000000000000000
--- a/chrome/browser/safe_browsing/verifier.cc
+++ /dev/null
@@ -1,168 +0,0 @@
-// Copyright 2014 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 "chrome/browser/safe_browsing/verifier.h"
-
-#include <windows.h>
-#include <psapi.h>
-
-#include "base/files/file_path.h"
-#include "base/files/memory_mapped_file.h"
-#include "base/win/pe_image.h"
-
-namespace safe_browsing {
-
-namespace {
-
-// The number of bytes made to agree (between memory and disk) when the
-// relocations are accounted for.
-int bytes_corrected_by_reloc = 0;
-
-// This is true if the relocation table contains a reloc of type we don't
-// currently handle.
-bool unknown_reloc_type = false;
-
-bool AddrIsInCodeSection(void* address, BYTE* code_addr, SIZE_T code_size) {
-  return (code_addr <= address && address <= code_addr + code_size);
-}
-
-bool GetCodeAddrsAndSize(const base::win::PEImage mem_peimage,
-                         base::win::PEImageAsData disk_peimage,
-                         BYTE*& mem_code_addr,
-                         BYTE*& disk_code_addr,
-                         SIZE_T& code_size) {
-  DWORD base_of_code = mem_peimage.GetNTHeaders()->OptionalHeader.BaseOfCode;
-
-  // Get the address and size of the code section in the loaded module image.
-  PIMAGE_SECTION_HEADER mem_code_header =
-      mem_peimage.GetImageSectionFromAddr(mem_peimage.RVAToAddr(base_of_code));
-  if (mem_code_header == NULL)
-    return false;
-  mem_code_addr = reinterpret_cast<BYTE*>(
-      mem_peimage.RVAToAddr(mem_code_header->VirtualAddress));
-  code_size = mem_code_header->Misc.VirtualSize;
-
-  // Get the address of the code section in the module mapped as data from disk.
-  // Section size will be the same as in the loaded module.
-  DWORD disk_code_offset = 0;
-  if (!mem_peimage.ImageAddrToOnDiskOffset(
-          reinterpret_cast<void*>(mem_code_addr), &disk_code_offset))
-    return false;
-  disk_code_addr =
-      reinterpret_cast<BYTE*>(disk_peimage.module()) + disk_code_offset;
-  return true;
-}
-
-int CountBytesDiffInPtr(intptr_t num_a, intptr_t num_b) {
-  int num_bytes = 0;
-  for (int i = 0; i < sizeof(num_a); ++i) {
-    if ((num_a & 0xFF) != (num_b & 0xFF))
-      ++num_bytes;
-    num_a >>= 8;
-    num_b >>= 8;
-  }
-  return num_bytes;
-}
-
-bool EnumRelocsCallback(const base::win::PEImage& mem_peimage,
-                        WORD type,
-                        void* address,
-                        void* cookie) {
-  base::win::PEImageAsData disk_peimage =
-      *reinterpret_cast<base::win::PEImageAsData*>(cookie);
-  BYTE* mem_code_addr = NULL;
-  BYTE* disk_code_addr = NULL;
-  SIZE_T code_size = 0;
-  if (!GetCodeAddrsAndSize(
-          mem_peimage, disk_peimage, mem_code_addr, disk_code_addr, code_size))
-    return false;
-
-  switch (type) {
-    case IMAGE_REL_BASED_HIGHLOW: {
-      // If not in the code section return true to continue to the next reloc.
-      if (!AddrIsInCodeSection(address, mem_code_addr, code_size))
-        return true;
-
-      BYTE* preferred_image_base = reinterpret_cast<BYTE*>(
-          disk_peimage.GetNTHeaders()->OptionalHeader.ImageBase);
-      intptr_t delta =
-          preferred_image_base - reinterpret_cast<BYTE*>(mem_peimage.module());
-      BYTE* new_value = (*reinterpret_cast<BYTE**>(address)) + delta;
-      int bytes_corrected =
-          CountBytesDiffInPtr(reinterpret_cast<intptr_t>(new_value),
-                              *reinterpret_cast<intptr_t*>(address));
-
-      // Check that the adding delta did correct the value to agree with disk.
-      BYTE** disk_address = reinterpret_cast<BYTE**>(
-          reinterpret_cast<BYTE*>(address) - mem_code_addr + disk_code_addr);
-      if (new_value == *disk_address) {
-        bytes_corrected_by_reloc += bytes_corrected;
-      }
-      break;
-    }
-    case IMAGE_REL_BASED_ABSOLUTE:
-      break;
-    default: {
-      // TODO(krstnmnlsn): Find a reliable description of the behaviour of the
-      // remaining types of relocation and handle them.
-      unknown_reloc_type = true;
-      break;
-    }
-  }
-  return true;
-}
-
-int CountBytesDiffInMemory(BYTE* disk_code_start,
-                           BYTE* memory_code_start,
-                           SIZE_T code_size) {
-  int counter = 0;
-  for (int i = 0; i < static_cast<int>(code_size); ++i) {
-    if (*(disk_code_start + i) != *(memory_code_start + i))
-      ++counter;
-  }
-  return counter;
-}
-
-}  // namespace
-
-ModuleState VerifyModule(wchar_t* module_name) {
-  HMODULE module_handle = GetModuleHandle(module_name);
-  if (module_handle == NULL)
-    return MODULE_STATE_UNKNOWN;
-
-  WCHAR module_path[MAX_PATH] = {0};
-  if (GetModuleFileNameEx(
-          GetCurrentProcess(), module_handle, module_path, MAX_PATH) == 0)
-    return MODULE_STATE_UNKNOWN;
-
-  base::MemoryMappedFile mapped_module;
-  mapped_module.Initialize(base::FilePath(module_path));
-  base::win::PEImageAsData disk_peimage(
-      reinterpret_cast<HMODULE>(const_cast<uint8*>(mapped_module.data())));
-
-  base::win::PEImage mem_peimage(module_handle);
-  if (!mem_peimage.VerifyMagic() || !disk_peimage.VerifyMagic())
-    return MODULE_STATE_UNKNOWN;
-
-  BYTE* mem_code_addr = NULL;
-  BYTE* disk_code_addr = NULL;
-  SIZE_T code_size = 0;
-  if (!GetCodeAddrsAndSize(
-          mem_peimage, disk_peimage, mem_code_addr, disk_code_addr, code_size))
-    return MODULE_STATE_UNKNOWN;
-
-  int num_bytes_different =
-      CountBytesDiffInMemory(disk_code_addr, mem_code_addr, code_size);
-  mem_peimage.EnumRelocs(
-      (base::win::PEImage::EnumRelocsFunction) & EnumRelocsCallback,
-      &disk_peimage);
-  if (unknown_reloc_type)
-    return MODULE_STATE_UNKNOWN;
-
-  if (num_bytes_different - bytes_corrected_by_reloc == 0)
-    return MODULE_STATE_UNMODIFIED;
-  return MODULE_STATE_MODIFIED;
-}
-
-}  // namespace safe_browsing