Ensure that NVDA can get file version information for binaries in system32 on 64-bit versions of Windows

source/config/__init__.py

@@ -102,7 +102,9 @@ def getInstalledUserConfigPath():
 		configInLocalAppData = bool(winreg.QueryValueEx(k, CONFIG_IN_LOCAL_APPDATA_SUBKEY)[0])
 	except WindowsError:
 		configInLocalAppData=False
-	configParent=shlobj.SHGetFolderPath(0, shlobj.CSIDL_LOCAL_APPDATA if configInLocalAppData else shlobj.CSIDL_APPDATA)
+	configParent = shlobj.SHGetKnownFolderPath(
+		shlobj.FOLDERID.LocalAppData.value if configInLocalAppData else shlobj.FOLDERID.RoamingAppData.value
+	)
 	try:
 		return os.path.join(configParent, "nvda")
 	except WindowsError:
@@ -126,14 +128,6 @@ def getUserDefaultConfigPath(useInstalledPathIfExists=False):
 		return installedUserConfigPath
 	return os.path.join(globalVars.appDir, 'userConfig')
 
-def getSystemConfigPath():
-	if isInstalledCopy():
-		try:
-			return os.path.join(shlobj.SHGetFolderPath(0, shlobj.CSIDL_COMMON_APPDATA), "nvda")
-		except WindowsError:
-			pass
-	return None
-
 
 SCRATCH_PAD_ONLY_DIRS = (
 	'appModules',

source/fileUtils.py

@@ -1,8 +1,7 @@
-#fileUtils.py
-#A part of NonVisual Desktop Access (NVDA)
-#Copyright (C) 2017-2019 NV Access Limited, Bram Duvigneau
-#This file is covered by the GNU General Public License.
-#See the file COPYING for more details.
+# A part of NonVisual Desktop Access (NVDA)
+# Copyright (C) 2017-2021 NV Access Limited, Bram Duvigneau, Łukasz Golonka
+# This file is covered by the GNU General Public License.
+# See the file COPYING for more details.
 
 import os
 import ctypes
@@ -13,6 +12,10 @@
 from logHandler import log
 from six import text_type
 import winKernel
+import shlobj
+from functools import wraps
+import systemUtils
+
 
 @contextmanager
 def FaultTolerantFile(name):
@@ -40,6 +43,32 @@ def FaultTolerantFile(name):
 		f.close()
 		winKernel.moveFileEx(f.name, name, winKernel.MOVEFILE_REPLACE_EXISTING)
 
+
+def _suspendWow64RedirectionForFileInfoRetrieval(func):
+	"""
+	This decorator checks if the file provided as a `filePath`
+	is placed in a system32 directory, and if for the current system system32
+	redirects 32-bit processes such as NVDA to a different syswow64 directory
+	disables redirection for the duration of the function call.
+	This is necessary when fetching file version info since NVDA is a 32-bit application
+	and without redirection disabled we would either access a wrong file or not be able to access it at all.
+	"""
+	@wraps(func)
+	def funcWrapper(filePath, *attributes):
+		nativeSys32 = shlobj.SHGetKnownFolderPath(shlobj.FOLDERID.System.value)
+		if (
+			systemUtils.hasSyswow64Dir()
+			# `os.path.commonpath` is necessary to perform case-insensitive comparisons
+			and os.path.commonpath([nativeSys32]) == os.path.commonpath([nativeSys32, filePath])
+		):
+			with winKernel.suspendWow64Redirection():
+				return func(filePath, *attributes)
+		else:
+			return func(filePath, *attributes)
+	return funcWrapper
+
+
+@_suspendWow64RedirectionForFileInfoRetrieval
 def getFileVersionInfo(name, *attributes):
 	"""Gets the specified file version info attributes from the provided file."""
 	if not isinstance(name, text_type):

source/shlobj.py

@@ -1,39 +1,56 @@
-# -*- coding: UTF-8 -*-
-#shlobj.py
-#A part of NonVisual Desktop Access (NVDA)
-#Copyright (C) 2006-2017 NV Access Limited, Babbage B.V.
-#This file is covered by the GNU General Public License.
-#See the file COPYING for more details.
+# A part of NonVisual Desktop Access (NVDA)
+# Copyright (C) 2009-2021 NV Access Limited, Babbage B.V., Łukasz Golonka
+# This file is covered by the GNU General Public License.
+# See the file COPYING for more details.
 
-"""
-This module wraps the SHGetFolderPath function in shell32.dll and defines the necessary contstants.
-CSIDL (constant special item ID list) values provide a unique system-independent way to
+r"""
+This module wraps the `SHGetKnownFolderPath` function in shell32.dll and defines the necessary contstants.
+Known folder ids provide a unique system-independent way to
 identify special folders used frequently by applications, but which may not have the same name
 or location on any given system. For example, the system folder may be "C:\Windows" on one system
-and "C:\Winnt" on another. The CSIDL system is used to be compatible with Windows XP.
+and "C:\Winnt" on another.
 """
 
-from ctypes import *
-from ctypes.wintypes import *
+import comtypes
+import ctypes
+import enum
+import functools
+import typing
 
-shell32 = windll.shell32
 
-MAX_PATH = 260
+class FOLDERID(str, enum.Enum):
+	"""Contains guids of known folders from Knownfolders.h. Full list is availabe at:
+	https://docs.microsoft.com/en-us/windows/win32/shell/knownfolderid"""
+	#: The file system directory that serves as a common repository for application-specific data.
+	#: A typical path is C:\Documents and Settings\username\Application Data.
+	RoamingAppData = "{3EB685DB-65F9-4CF6-A03A-E3EF65729F3D}"
+	#: The file system directory that serves as a data repository for local (nonroaming) applications.
+	#: A typical path is C:\Documents and Settings\username\Local Settings\Application Data.
+	LocalAppData = "{F1B32785-6FBA-4FCF-9D55-7B8E7F157091}"
+	#: The file system directory that contains application data for all users.
+	#: A typical path is C:\Documents and Settings\All Users\Application Data.
+	#: This folder is used for application data that is not user specific.
+	ProgramData = "{62AB5D82-FDC1-4DC3-A9DD-070D1D495D97}"
+	#  The Windows System folder.
+	# A typical path is C:\Windows\System32.
+	System = "{1AC14E77-02E7-4E5D-B744-2EB1AE5198B7}"
+	SystemX86 = "{D65231B0-B2F1-4857-A4CE-A8E7C6EA7D27}"
 
-#: The file system directory that serves as a common repository for application-specific data.
-#: A typical path is C:\Documents and Settings\username\Application Data.
-CSIDL_APPDATA = 0x001a
-#: The file system directory that serves as a data repository for local (nonroaming) applications.
-#: A typical path is C:\Documents and Settings\username\Local Settings\Application Data.
-CSIDL_LOCAL_APPDATA = 0x001c
-#: The file system directory that contains application data for all users.
-#: A typical path is C:\Documents and Settings\All Users\Application Data.
-#: This folder is used for application data that is not user specific.
-CSIDL_COMMON_APPDATA = 0x0023
 
-def SHGetFolderPath(owner, folder, token=0, flags=0):
-	path = create_unicode_buffer(MAX_PATH)
-	# Note  As of Windows Vista, this function is merely a wrapper for SHGetKnownFolderPath
-	if shell32.SHGetFolderPathW(owner, folder, token, flags, byref(path)) != 0:
-		raise WinError()
-	return path.value
+@functools.lru_cache(maxsize=128)
+def SHGetKnownFolderPath(folderGuid: str, dwFlags: int = 0, hToken: typing.Optional[int] = None) -> str:
+	"""Wrapper for `SHGetKnownFolderPath` which caches the results
+	to avoid calling the win32 function unnecessarily."""
+	guid = comtypes.GUID(folderGuid)
+	pathPointer = ctypes.c_wchar_p()
+	res = ctypes.windll.shell32.SHGetKnownFolderPath(
+		comtypes.byref(guid),
+		dwFlags,
+		hToken,
+		ctypes.byref(pathPointer)
+	)
+	if res != 0:
+		raise RuntimeError(f"SHGetKnownFolderPath failed with erro code {res}")
+	path = pathPointer.value
+	ctypes.windll.ole32.CoTaskMemFree(pathPointer)
+	return path

source/systemUtils.py

@@ -10,6 +10,17 @@
 import shellapi
 import winUser
 import os
+import functools
+import shlobj
+
+
+@functools.lru_cache(maxsize=1)
+def hasSyswow64Dir() -> bool:
+	"""Returns `True` if the current system has separate system32 directories for 32-bit processes."""
+	nativeSys32 = shlobj.SHGetKnownFolderPath(shlobj.FOLDERID.System.value)
+	Syswow64Sys32 = shlobj.SHGetKnownFolderPath(shlobj.FOLDERID.SystemX86.value)
+	return nativeSys32 != Syswow64Sys32
+
 
 def openUserConfigurationDirectory():
 	"""Opens directory containing config files for the current user"""

source/winKernel.py

@@ -150,6 +150,36 @@ def GetSystemPowerStatus(sps):
 def getThreadLocale():
 	return kernel32.GetThreadLocale()
 
+
+ERROR_INVALID_FUNCTION = 0x1
+
+
+@contextlib.contextmanager
+def suspendWow64Redirection():
+	"""Context manager which disables Wow64 redirection for a section of code and re-enables it afterwards"""
+	oldValue = LPVOID()
+	res = kernel32.Wow64DisableWow64FsRedirection(byref(oldValue))
+	if res == 0:
+		# Disabling redirection failed.
+		# This can occur if we're running on 32-bit Windows (no Wow64 redirection)
+		# or as a 64-bit process on 64-bit Windows (Wow64 redirection not applicable)
+		# In this case failure is expected and there is no reason to raise an exception.
+		# Inspect last error code to determine reason for the failure.
+		errorCode = kernel32.GetLastError()
+		if errorCode == ERROR_INVALID_FUNCTION:  # Redirection not supported or not applicable.
+			redirectionDisabled = False
+		else:
+			raise WinError(errorCode)
+	else:
+		redirectionDisabled = True
+	try:
+		yield
+	finally:
+		if redirectionDisabled:
+			if kernel32.Wow64RevertWow64FsRedirection(oldValue) == 0:
+				raise WinError()
+
+
 class SYSTEMTIME(ctypes.Structure):
 	_fields_ = (
 		("wYear", WORD),