seanbudd · Oct 25, 2021 · Oct 16, 2021 · Oct 16, 2021 · Oct 16, 2021 · Oct 16, 2021
diff --git a/source/appModuleHandler.py b/source/appModuleHandler.py
@@ -34,6 +34,15 @@
 import watchdog
 import extensionPoints
 from fileUtils import getFileVersionInfo
+import shlobj
+from functools import wraps
+
+# Path to the native system32 directory.
+nativeSys32: str = shlobj.SHGetFolderPath(None, shlobj.CSIDL.SYSTEM)
+# Path to the syswow64 directory if it exists on the current system.
+Syswow64Sys32: str = shlobj.SHGetFolderPath(None, shlobj.CSIDL.SYSTEMX86)
+# Do we have separate system32 directories for 32 and 64-bit processes?
+hasSeparateSyswow64: bool = nativeSys32 != Syswow64Sys32
 
 #Dictionary of processID:appModule paires used to hold the currently running modules
 runningTable={}
@@ -302,6 +311,27 @@ def handleAppSwitch(oldMods, newMods):
 		if not mod.sleepMode and hasattr(mod,'event_appModule_gainFocus'):
 			mod.event_appModule_gainFocus()
 
+
+def _suspendWow64RedirectionForFileInfoRetrieval(func):
+	"""Decorator which should be used for functions which need to access binaries backing given appModule.
+	It checks if the given binary 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 method call."""
+	@wraps(func)
+	def funcWrapper(self):
+		if (
+			hasSeparateSyswow64
+			and self.appPath
+			# `os.path.commonpath` is necessary to perfor case-insensitive comparisons
+			and os.path.commonpath([nativeSys32]) == os.path.commonpath([nativeSys32, self.appPath])
+		):
+			with winKernel.suspendWow64Redirection():
+				return func(self)
+		else:
+			return func(self)
+	return funcWrapper
+
+
 #base class for appModules
 class AppModule(baseObject.ScriptableObject):
 	"""Base app module.
@@ -379,6 +409,7 @@ def _getImmersivePackageInfo(self):
 		else:
 			return None
 
+	@_suspendWow64RedirectionForFileInfoRetrieval
 	def _setProductInfo(self):
 		"""Set productName and productVersion attributes.
 		There are at least two ways of obtaining product info for an app:

@@ -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.SHGetFolderPath(
+		0, shlobj.CSIDL.LOCAL_APPDATA if configInLocalAppData else shlobj.CSIDL.APPDATA
+	)
 	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',

@@ -1,37 +1,43 @@
-# -*- 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.
 
-"""
+r"""
 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
 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.
 """
 
-from ctypes import *
-from ctypes.wintypes import *
+from ctypes import byref, create_unicode_buffer, windll, WinError
+import enum
+import typing
 
 shell32 = windll.shell32
 
 MAX_PATH = 260
 
-#: 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):
+
+class CSIDL(enum.IntEnum):
+	#: 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.
+	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.
+	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.
+	COMMON_APPDATA = 0x0023
+	#  The Windows System folder.
+	# A typical path is C:\Windows\System32.
+	SYSTEM = 0x25
+	SYSTEMX86 = 0x29
+
+
+def SHGetFolderPath(owner: typing.Union[None, int], folder: CSIDL, token: int = 0, flags: int = 0) -> str:
 	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:

@@ -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),