Revert 245464 "Use an alternate mechanism for CreateFile calls i..."

trunk/src/chrome_elf/create_file/chrome_create_file.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_elf/create_file/chrome_create_file.h"
-
-#include <string>
-
-#include "base/strings/string16.h"
-#include "chrome_elf/chrome_elf_constants.h"
-#include "chrome_elf/ntdll_cache.h"
-#include "sandbox/win/src/nt_internals.h"
-
-namespace {
-
-// From ShlObj.h in the Windows SDK.
-#define CSIDL_LOCAL_APPDATA 0x001c
-
-typedef BOOL (WINAPI *PathIsUNCFunction)(
-  IN LPCWSTR path);
-
-typedef BOOL (WINAPI *PathAppendFunction)(
-  IN LPWSTR path,
-  IN LPCWSTR more);
-
-typedef BOOL (WINAPI *PathIsPrefixFunction)(
-  IN LPCWSTR prefix,
-  IN LPCWSTR path);
-
-typedef HRESULT (WINAPI *SHGetFolderPathFunction)(
-  IN HWND hwnd_owner,
-  IN int folder,
-  IN HANDLE token,
-  IN DWORD flags,
-  OUT LPWSTR path);
-
-PathIsUNCFunction g_path_is_unc_func;
-PathAppendFunction g_path_append_func;
-PathIsPrefixFunction g_path_is_prefix_func;
-SHGetFolderPathFunction g_get_folder_func;
-
-// Populates the g_*_func pointers to functions which will be used in
-// ShouldBypass(). Chrome_elf cannot have a load-time dependency on shell32 or
-// shlwapi as this would induce a load-time dependency on user32.dll. Instead,
-// the addresses of the functions we need are retrieved the first time this
-// method is called, and cached to avoid subsequent calls to GetProcAddress().
-// It is assumed that the host process will never unload these functions.
-// Returns true if all the functions needed are present.
-bool PopulateShellFunctions() {
-  // Early exit if functions have already been populated.
-  if (g_path_is_unc_func && g_path_append_func &&
-      g_path_is_prefix_func && g_get_folder_func) {
-    return true;
-  }
-
-  // Get the addresses of the functions we need and store them for future use.
-  // These handles are intentionally leaked to ensure that these modules do not
-  // get unloaded.
-  HMODULE shell32 = ::LoadLibrary(L"shell32.dll");
-  HMODULE shlwapi = ::LoadLibrary(L"shlwapi.dll");
-
-  if (!shlwapi || !shell32)
-    return false;
-
-  g_path_is_unc_func = reinterpret_cast<PathIsUNCFunction>(
-      ::GetProcAddress(shlwapi, "PathIsUNCW"));
-  g_path_append_func = reinterpret_cast<PathAppendFunction>(
-      ::GetProcAddress(shlwapi, "PathAppendW"));
-  g_path_is_prefix_func = reinterpret_cast<PathIsPrefixFunction>(
-      ::GetProcAddress(shlwapi, "PathIsPrefixW"));
-  g_get_folder_func = reinterpret_cast<SHGetFolderPathFunction>(
-      ::GetProcAddress(shell32, "SHGetFolderPathW"));
-
-  return g_path_is_unc_func && g_path_append_func &&
-      g_path_is_prefix_func && g_get_folder_func;
-}
-
-}  // namespace
-
-HANDLE WINAPI CreateFileWRedirect(
-    LPCWSTR file_name,
-    DWORD desired_access,
-    DWORD share_mode,
-    LPSECURITY_ATTRIBUTES security_attributes,
-    DWORD creation_disposition,
-    DWORD flags_and_attributes,
-    HANDLE template_file) {
-  if (ShouldBypass(file_name)) {
-    return CreateFileNTDLL(file_name,
-                           desired_access,
-                           share_mode,
-                           security_attributes,
-                           creation_disposition,
-                           flags_and_attributes,
-                           template_file);
-  }
-  return CreateFile(file_name,
-                    desired_access,
-                    share_mode,
-                    security_attributes,
-                    creation_disposition,
-                    flags_and_attributes,
-                    template_file);
-
-}
-
-HANDLE CreateFileNTDLL(
-    LPCWSTR file_name,
-    DWORD desired_access,
-    DWORD share_mode,
-    LPSECURITY_ATTRIBUTES security_attributes,
-    DWORD creation_disposition,
-    DWORD flags_and_attributes,
-    HANDLE template_file) {
-  HANDLE file_handle = INVALID_HANDLE_VALUE;
-  NTSTATUS result = STATUS_UNSUCCESSFUL;
-  IO_STATUS_BLOCK io_status_block = {};
-
-  // Convert from Win32 domain to to NT creation disposition values.
-  switch (creation_disposition) {
-    case CREATE_NEW:
-      creation_disposition = FILE_CREATE;
-      break;
-    case CREATE_ALWAYS:
-      creation_disposition = FILE_OVERWRITE_IF;
-      break;
-    case OPEN_EXISTING:
-      creation_disposition = FILE_OPEN;
-      break;
-    case OPEN_ALWAYS:
-      creation_disposition = FILE_OPEN_IF;
-      break;
-    case TRUNCATE_EXISTING:
-      creation_disposition = FILE_OVERWRITE;
-      break;
-    default:
-      SetLastError(ERROR_INVALID_PARAMETER);
-      return INVALID_HANDLE_VALUE;
-  }
-
-  if (!g_ntdll_lookup["NtCreateFile"] ||
-      !g_ntdll_lookup["RtlInitUnicodeString"]) {
-    return INVALID_HANDLE_VALUE;
-  }
-
-  NtCreateFileFunction create_file =
-      reinterpret_cast<NtCreateFileFunction>(g_ntdll_lookup["NtCreateFile"]);
-
-  RtlInitUnicodeStringFunction init_unicode_string =
-      reinterpret_cast<RtlInitUnicodeStringFunction>(
-          g_ntdll_lookup["RtlInitUnicodeString"]);
-
-  UNICODE_STRING path_unicode_string;
-
-  // Format the path into an NT path. Arguably this should be done with
-  // RtlDosPathNameToNtPathName_U, but afaict this is equivalent for
-  // local paths. Using this with a UNC path name will almost certainly
-  // break in interesting ways.
-  base::string16 filename_string(L"\\??\\");
-  filename_string += file_name;
-
-  init_unicode_string(&path_unicode_string, filename_string.c_str());
-
-  OBJECT_ATTRIBUTES path_attributes = {};
-  InitializeObjectAttributes(&path_attributes,
-                             &path_unicode_string,
-                             OBJ_CASE_INSENSITIVE,
-                             NULL,   // No Root Directory
-                             NULL);  // No Security Descriptor
-
-  // Set create_options, desired_access, and flags_and_attributes to match those
-  // set by kernel32!CreateFile.
-  ULONG create_options = FILE_ATTRIBUTE_DEVICE | FILE_ATTRIBUTE_ARCHIVE;
-  desired_access |= 0x100080;
-  flags_and_attributes &= 0x2FFA7;
-
-  result = create_file(&file_handle,
-                       desired_access,
-                       &path_attributes,
-                       &io_status_block,
-                       0,  // Allocation size
-                       flags_and_attributes,
-                       share_mode,
-                       creation_disposition,
-                       create_options,
-                       NULL,
-                       0);
-
-  if (result != STATUS_SUCCESS) {
-    if (result == STATUS_OBJECT_NAME_COLLISION &&
-        creation_disposition == FILE_CREATE) {
-      SetLastError(ERROR_FILE_EXISTS);
-    }
-    return INVALID_HANDLE_VALUE;
-  }
-
-  if (creation_disposition == FILE_OPEN_IF) {
-    SetLastError(io_status_block.Information == FILE_OPENED ?
-        ERROR_ALREADY_EXISTS : ERROR_SUCCESS);
-  } else if (creation_disposition == FILE_OVERWRITE_IF) {
-    SetLastError(io_status_block.Information == FILE_OVERWRITTEN ?
-        ERROR_ALREADY_EXISTS : ERROR_SUCCESS);
-  } else {
-    SetLastError(ERROR_SUCCESS);
-  }
-
-  return file_handle;
-}
-
-bool ShouldBypass(LPCWSTR file_name) {
-  // If the shell functions are not present, forward the call to kernel32.
-  if (!PopulateShellFunctions())
-    return false;
-
-  // Forward all UNC filepaths to kernel32.
-  if (g_path_is_unc_func(file_name))
-    return false;
-
-  wchar_t local_appdata_path[MAX_PATH];
-
-  // Get the %LOCALAPPDATA% Path and append the location of our UserData
-  // directory to it.
-  HRESULT appdata_result = g_get_folder_func(
-      NULL, CSIDL_LOCAL_APPDATA, NULL, 0, local_appdata_path);
-
-  // If getting the %LOCALAPPDATA% path or appending to it failed, then forward
-  // the call to kernel32.
-  if (!SUCCEEDED(appdata_result) ||
-      !g_path_append_func(local_appdata_path, kAppDataDirName) ||
-      !g_path_append_func(local_appdata_path, kUserDataDirName)) {
-    return false;
-  }
-
-  // Check if we are trying to access something in the UserData dir. If so,
-  // then redirect the call to bypass kernel32.
-  return !!g_path_is_prefix_func(local_appdata_path, file_name);
-}