Use an alternate mechanism for CreateFile calls in Chrome

chrome_elf/create_file/chrome_create_file_unittest.cc

+// Copyright 2013 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_elf/create_file/chrome_create_file.h"
+
+#include <windows.h>
+
+#include <bitset>
+#include <string>
+
+#include "base/base_paths_win.h"
+#include "base/file_util.h"
+#include "base/files/file_path.h"
+#include "base/files/scoped_temp_dir.h"
+#include "base/path_service.h"
+#include "base/threading/platform_thread.h"
+#include "base/win/iat_patch_function.h"
+#include "base/win/scoped_handle.h"
+#include "base/win/windows_version.h"
+#include "chrome_elf/chrome_elf_constants.h"
+#include "chrome_elf/ntdll_cache.h"
+#include "sandbox/win/src/nt_internals.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "testing/platform_test.h"
+
+
+namespace {
+
+// Test fixtures -------------------------------------------------------------
+
+class ChromeCreateFileTest : public PlatformTest {
+ protected:
+  struct NtCreateFileParams {
+    ACCESS_MASK desired_access;
+    OBJECT_ATTRIBUTES object_attributes;
+    PLARGE_INTEGER allocation_size;
+    ULONG file_attributes;
+    ULONG share_access;
+    ULONG create_disposition;
+    ULONG create_options;
+    PVOID ea_buffer;
+    ULONG ea_length;
+  };
+
+  enum CallPath {
+    ELF,
+    KERNEL
+  };
+
+  template<CallPath path>
+  static NTSTATUS WINAPI FakeNtCreateFile(
+      PHANDLE file_handle,
+      ACCESS_MASK desired_access,
+      POBJECT_ATTRIBUTES object_attributes,
+      PIO_STATUS_BLOCK io_status_block,
+      PLARGE_INTEGER allocation_size,
+      ULONG file_attributes,
+      ULONG share_access,
+      ULONG create_disposition,
+      ULONG create_options,
+      PVOID ea_buffer,
+      ULONG ea_length) {
+    return self_->HandleCreateFileCall(file_handle,
+        desired_access,
+        object_attributes,
+        io_status_block,
+        allocation_size,
+        file_attributes,
+        share_access,
+        create_disposition,
+        create_options,
+        ea_buffer,
+        ea_length,
+        path);
+  }
+
+  virtual void SetUp() OVERRIDE {
+    original_thread_ = base::PlatformThread::CurrentId();
+    InitCache();
+    PlatformTest::SetUp();
+
+    base::FilePath user_data_dir;
+    PathService::Get(base::DIR_LOCAL_APP_DATA, &user_data_dir);
+    ASSERT_TRUE(temp_dir_.CreateUniqueTempDirUnderPath(user_data_dir));
+    ASSERT_TRUE(temp_dir2_.CreateUniqueTempDir());
+    self_ = this;
+  }
+
+  void RedirectNtCreateFileCalls() {
+    old_func_ptr_ =
+        reinterpret_cast<NtCreateFileFunction>(g_ntdll_lookup["NtCreateFile"]);
+
+    // KernelBase.dll only exists for Win7 and later, prior to that, kernel32
+    // imports from ntdll directly.
+    if (base::win::GetVersion() < base::win::VERSION_WIN7) {
+      patcher_.Patch(L"kernel32.dll", "ntdll.dll", "NtCreateFile",
+          reinterpret_cast<void(*)()>(&FakeNtCreateFile<KERNEL>));
+    } else {
+      patcher_.Patch(L"kernelbase.dll", "ntdll.dll", "NtCreateFile",
+          reinterpret_cast<void(*)()>(&FakeNtCreateFile<KERNEL>));
+    }
+
+    g_ntdll_lookup["NtCreateFile"] = reinterpret_cast<void(*)()>(
+        &ChromeCreateFileTest::FakeNtCreateFile<ELF>);
+  }
+
+  void ResetNtCreateFileCalls() {
+    g_ntdll_lookup["NtCreateFile"] = reinterpret_cast<void*>(old_func_ptr_);
+    patcher_.Unpatch();
+  }
+
+  NTSTATUS HandleCreateFileCall(PHANDLE file_handle,
+      ACCESS_MASK desired_access,
+      POBJECT_ATTRIBUTES object_attributes,
+      PIO_STATUS_BLOCK io_status_block,
+      PLARGE_INTEGER allocation_size,
+      ULONG file_attributes,
+      ULONG share_access,
+      ULONG create_disposition,
+      ULONG create_options,
+      PVOID ea_buffer,
+      ULONG ea_length,
+      CallPath call_path) {
+    if (original_thread_ == base::PlatformThread::CurrentId()) {
+      SetParams(desired_access,
+          object_attributes,
+          allocation_size,
+          file_attributes,
+          share_access,
+          create_disposition,
+          create_options,
+          ea_buffer,
+          ea_length,
+          call_path == ELF ? &elf_params_ : &kernel_params_);
+    }
+
+    // Forward the call to the real NTCreateFile.
+    return old_func_ptr_(file_handle,
+        desired_access,
+        object_attributes,
+        io_status_block,
+        allocation_size,
+        file_attributes,
+        share_access,
+        create_disposition,
+        create_options,
+        ea_buffer,
+        ea_length);
+  }
+
+  void SetParams(ACCESS_MASK desired_access,
+      POBJECT_ATTRIBUTES object_attributes,
+      PLARGE_INTEGER allocation_size,
+      ULONG file_attributes,
+      ULONG share_access,
+      ULONG create_disposition,
+      ULONG create_options,
+      PVOID ea_buffer,
+      ULONG ea_length,
+      NtCreateFileParams* params) {
+    params->desired_access = desired_access;
+    params->object_attributes.Length = object_attributes->Length;
+    params->object_attributes.ObjectName = object_attributes->ObjectName;
+    params->object_attributes.RootDirectory = object_attributes->RootDirectory;
+    params->object_attributes.Attributes = object_attributes->Attributes;
+    params->object_attributes.SecurityDescriptor =
+        object_attributes->SecurityDescriptor;
+    params->object_attributes.SecurityQualityOfService =
+        object_attributes->SecurityQualityOfService;
+    params->allocation_size = allocation_size;
+    params->file_attributes = file_attributes;
+    params->share_access = share_access;
+    params->create_disposition = create_disposition;
+    params->create_options = create_options;
+    params->ea_buffer = ea_buffer;
+    params->ea_length = ea_length;
+  }
+
+  void CheckParams() {
+    std::bitset<32> elf((int) elf_params_.desired_access);
+    std::bitset<32> ker((int) kernel_params_.desired_access);
+
+    EXPECT_EQ(kernel_params_.desired_access, elf_params_.desired_access)
+        << elf << "\n" << ker;
+    EXPECT_EQ(kernel_params_.object_attributes.Length,
+              elf_params_.object_attributes.Length);
+    EXPECT_EQ(kernel_params_.object_attributes.RootDirectory,
+              elf_params_.object_attributes.RootDirectory);
+    EXPECT_EQ(kernel_params_.object_attributes.Attributes,
+              elf_params_.object_attributes.Attributes);
+    EXPECT_EQ(kernel_params_.object_attributes.SecurityDescriptor,
+              elf_params_.object_attributes.SecurityDescriptor);
+    EXPECT_EQ(kernel_params_.allocation_size, elf_params_.allocation_size);
+    EXPECT_EQ(kernel_params_.file_attributes, elf_params_.file_attributes);
+    EXPECT_EQ(kernel_params_.share_access, elf_params_.share_access);
+    EXPECT_EQ(kernel_params_.create_disposition,
+              elf_params_.create_disposition);
+    EXPECT_EQ(kernel_params_.create_options, elf_params_.create_options);
+    EXPECT_EQ(kernel_params_.ea_buffer, elf_params_.ea_buffer);
+    EXPECT_EQ(kernel_params_.ea_length, elf_params_.ea_length);
+  }
+
+  void DoWriteCheck(const base::FilePath& path, bool is_system) {
+    base::win::ScopedHandle file_handle;
+    const char kTestData[] = "0123456789";
+    int buffer_size = sizeof(kTestData) - 1;
+    DWORD bytes_written;
+
+    if (is_system) {
+      file_handle.Set(::CreateFileW(path.value().c_str(),
+                                    GENERIC_WRITE,
+                                    0,
+                                    NULL,
+                                    CREATE_ALWAYS,
+                                    FILE_ATTRIBUTE_NORMAL,
+                                    NULL));
+    } else {
+      file_handle.Set(CreateFileNTDLL(path.value().c_str(),
+                                      GENERIC_WRITE,
+                                      0,
+                                      NULL,
+                                      CREATE_ALWAYS,
+                                      FILE_ATTRIBUTE_NORMAL,
+                                      NULL));
+    }
+
+
+    EXPECT_FALSE(file_handle == INVALID_HANDLE_VALUE);
+    ::WriteFile(file_handle, kTestData, buffer_size, &bytes_written, NULL);
+    EXPECT_EQ(buffer_size, bytes_written);
+  }
+
+  void DoReadCheck(const base::FilePath& path, bool is_system) {
+    base::win::ScopedHandle file_handle;
+    const char kTestData[] = "0123456789";
+    int buffer_size = sizeof(kTestData) - 1;
+    DWORD bytes_read;
+    char read_buffer[10];
+
+     if (is_system) {
+      file_handle.Set(::CreateFileW(path.value().c_str(),
+                                    GENERIC_READ,
+                                    0,
+                                    NULL,
+                                    OPEN_ALWAYS,
+                                    FILE_ATTRIBUTE_NORMAL,
+                                    NULL));
+    } else {
+      file_handle.Set(CreateFileNTDLL(path.value().c_str(),
+                                      GENERIC_READ,
+                                      0,
+                                      NULL,
+                                      OPEN_ALWAYS,
+                                      FILE_ATTRIBUTE_NORMAL,
+                                      NULL));
+    }
+
+    EXPECT_FALSE(file_handle == INVALID_HANDLE_VALUE);
+    ::ReadFile(file_handle, read_buffer, buffer_size, &bytes_read, NULL);
+    EXPECT_EQ(buffer_size, bytes_read);
+    EXPECT_EQ(0, memcmp(kTestData, read_buffer, bytes_read));
+  }
+
+  static ChromeCreateFileTest* self_;
+
+  NtCreateFileFunction old_func_ptr_;
+  base::ScopedTempDir temp_dir_;
+  base::ScopedTempDir temp_dir2_;
+  base::win::IATPatchFunction patcher_;
+  NtCreateFileParams kernel_params_;
+  NtCreateFileParams elf_params_;
+  base::PlatformThreadId original_thread_;
+};
+
+ChromeCreateFileTest* ChromeCreateFileTest::self_ = NULL;
+
+// Tests ---------------------------------------------------------------------
+
+TEST_F(ChromeCreateFileTest, CheckWriteAndReadParams) {
+  RedirectNtCreateFileCalls();
+
+  // Make sure we can write to this file handle when called via the system.
+  base::FilePath junk_path_1 = temp_dir_.path().Append(L"junk_1.txt");
+  base::FilePath junk_path_2 = temp_dir_.path().Append(L"junk_2.txt");
+  DoWriteCheck(junk_path_1, true);
+  DoWriteCheck(junk_path_2, false);
+  CheckParams();
+
+  // Make sure we can read from this file handle when called via the system.
+  DoReadCheck(junk_path_1, true);
+  DoReadCheck(junk_path_2, false);
+  CheckParams();
+
+  ResetNtCreateFileCalls();
+}
+
+TEST_F(ChromeCreateFileTest, BypassTest) {
+  std::wstring UNC_filepath_file(L"\\\\.\\some_file.txt");
+
+  base::FilePath local_path;
+  PathService::Get(base::DIR_LOCAL_APP_DATA, &local_path);
+  local_path = local_path.Append(kAppDataDirName).Append(
+      kUserDataDirName).Append(L"default\\Preferences");
+
+  base::FilePath desktop_path;
+  PathService::Get(base::DIR_USER_DESKTOP, &desktop_path);
+  desktop_path = desktop_path.Append(L"Downloads\\junk.txt");
+
+  EXPECT_FALSE(ShouldBypass(UNC_filepath_file.c_str()));
+  EXPECT_FALSE(ShouldBypass(desktop_path.value().c_str()));
+  EXPECT_TRUE(ShouldBypass(local_path.value().c_str()));
+}
+
+TEST_F(ChromeCreateFileTest, NtCreateFileAddressCheck) {
+  HMODULE ntdll_handle = ::GetModuleHandle(L"ntdll.dll");
+  EXPECT_EQ(::GetProcAddress(ntdll_handle, "NtCreateFile"),
+            g_ntdll_lookup["NtCreateFile"]);
+}
+
+TEST_F(ChromeCreateFileTest, ReadWriteFromNtDll) {
+  base::FilePath file_name = temp_dir_.path().Append(L"some_file.txt");
+  DoWriteCheck(file_name, false);
+  DoReadCheck(file_name, false);
+}
+
+}  // namespace