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

chrome/browser/safe_browsing/module_integrity_verifier_win_unittest.cc

+// 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/module_integrity_verifier_win.h"
+
+#include "base/files/file_path.h"
+#include "base/files/memory_mapped_file.h"
+#include "base/native_library.h"
+#include "base/path_service.h"
+#include "base/scoped_native_library.h"
+#include "base/win/pe_image.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace safe_browsing {
+
+namespace {
+
+const wchar_t kTestDllName[] = L"verifier_test_dll.dll";
+const char kTestExportName[] = "DummyExport";
+
+}  // namespace
+
+class SafeBrowsingModuleVerifierWinTest : public testing::Test {
+ protected:
+  void SetUpTestDllAndPEImages() {
+    LoadModule();
+    HMODULE mem_handle;
+    GetMemModuleHandle(&mem_handle);
+    mem_peimage_ptr_.reset(new base::win::PEImage(mem_handle));
+    ASSERT_TRUE(mem_peimage_ptr_->VerifyMagic());
+
+    LoadDLLAsFile();
+    HMODULE disk_handle;
+    GetDiskModuleHandle(&disk_handle);
+    disk_peimage_ptr_.reset(new base::win::PEImageAsData(disk_handle));
+    ASSERT_TRUE(disk_peimage_ptr_->VerifyMagic());
+  }
+
+  void LoadModule() {
+    mem_dll_handle_.Reset(
+        LoadNativeLibrary(base::FilePath(kTestDllName), NULL));
+    ASSERT_TRUE(mem_dll_handle_.is_valid());
+  }
+
+  void GetMemModuleHandle(HMODULE* mem_handle) {
+    *mem_handle = GetModuleHandle(kTestDllName);
+    ASSERT_NE(static_cast<HMODULE>(NULL), *mem_handle);
+  }
+
+  void LoadDLLAsFile() {
+    // Use the module handle to find the it on disk, then load as a file.
+    HMODULE module_handle;
+    GetMemModuleHandle(&module_handle);
+
+    WCHAR module_path[MAX_PATH] = {};
+    DWORD length =
+        GetModuleFileName(module_handle, module_path, arraysize(module_path));
+    ASSERT_NE(arraysize(module_path), length);
+    ASSERT_TRUE(disk_dll_handle_.Initialize(base::FilePath(module_path)));
+  }
+
+  void GetDiskModuleHandle(HMODULE* disk_handle) {
+    *disk_handle =
+        reinterpret_cast<HMODULE>(const_cast<uint8*>(disk_dll_handle_.data()));
+  }
+
+  // Edits the first byte of the single function exported by the test dll.
+  void EditExport() {
+    HMODULE mem_handle;
+    GetMemModuleHandle(&mem_handle);
+    uint8_t* export_addr =
+        reinterpret_cast<uint8_t*>(GetProcAddress(mem_handle, kTestExportName));
+    EXPECT_NE(reinterpret_cast<uint8_t*>(NULL), export_addr);
+
+    // Edit the first byte of the function.
+    uint8_t new_val = (*export_addr) + 1;
+    SIZE_T bytes_written = 0;
+    WriteProcessMemory(GetCurrentProcess(),
+                       export_addr,
+                       reinterpret_cast<void*>(&new_val),
+                       1,
+                       &bytes_written);
+    EXPECT_EQ(1, bytes_written);
+  }
+
+  base::ScopedNativeLibrary mem_dll_handle_;
+  base::MemoryMappedFile disk_dll_handle_;
+  scoped_ptr<base::win::PEImageAsData> disk_peimage_ptr_;
+  scoped_ptr<base::win::PEImage> mem_peimage_ptr_;
+};
+
+TEST_F(SafeBrowsingModuleVerifierWinTest, VerifyModuleUnmodified) {
+  std::set<std::string> modified_exports;
+  // Call VerifyModule before the module has been loaded, should fail.
+  EXPECT_EQ(MODULE_STATE_UNKNOWN,
+            VerifyModule(kTestDllName, &modified_exports));
+  EXPECT_EQ(0, modified_exports.size());
+
+  // On loading, the module should be identical (up to relocations) in memory as
+  // on disk.
+  SetUpTestDllAndPEImages();
+  EXPECT_EQ(MODULE_STATE_UNMODIFIED,
+            VerifyModule(kTestDllName, &modified_exports));
+  EXPECT_EQ(0, modified_exports.size());
+}
+
+TEST_F(SafeBrowsingModuleVerifierWinTest, VerifyModuleModified) {
+  std::set<std::string> modified_exports;
+  // Confirm the module is identical in memory as on disk before we begin.
+  SetUpTestDllAndPEImages();
+  EXPECT_EQ(MODULE_STATE_UNMODIFIED,
+            VerifyModule(kTestDllName, &modified_exports));
+
+  uint8_t* mem_code_addr = NULL;
+  uint8_t* disk_code_addr = NULL;
+  uint32_t code_size = 0;
+  EXPECT_TRUE(GetCodeAddrsAndSize(*mem_peimage_ptr_,
+                                  *disk_peimage_ptr_,
+                                  &mem_code_addr,
+                                  &disk_code_addr,
+                                  &code_size));
+
+  // Edit the first byte of the code section of the module (this may be before
+  // the address of any export).
+  uint8_t new_val = (*mem_code_addr) + 1;
+  SIZE_T bytes_written = 0;
+  WriteProcessMemory(GetCurrentProcess(),
+                     mem_code_addr,
+                     reinterpret_cast<void*>(&new_val),
+                     1,
+                     &bytes_written);
+  EXPECT_EQ(1, bytes_written);
+
+  // VerifyModule should detect the change.
+  EXPECT_EQ(MODULE_STATE_MODIFIED,
+            VerifyModule(kTestDllName, &modified_exports));
+}
+
+TEST_F(SafeBrowsingModuleVerifierWinTest, VerifyModuleExportModified) {
+  std::set<std::string> modified_exports;
+  // Confirm the module is identical in memory as on disk before we begin.
+  SetUpTestDllAndPEImages();
+  EXPECT_EQ(MODULE_STATE_UNMODIFIED,
+            VerifyModule(kTestDllName, &modified_exports));
+  modified_exports.clear();
+
+  // Edit the exported function, VerifyModule should now return the function
+  // name in modified_exports.
+  EditExport();
+  EXPECT_EQ(MODULE_STATE_MODIFIED,
+            VerifyModule(kTestDllName, &modified_exports));
+  EXPECT_EQ(1, modified_exports.size());
+  EXPECT_EQ(0, std::string(kTestExportName).compare(*modified_exports.begin()));
+}
+
+}  // namespace safe_browsing