Use ctypes on win32

extensions.py

@@ -25,11 +25,4 @@ def get_extensions():
                             'CoreServices'])
         exts.append(osx_keychain_module)
 
-    if platform in ['win32'] and sys.getwindowsversion()[-2] == 2:
-        # windows 2k+
-        win32_crypto_module = Extension('win32_crypto',
-                libraries = ['crypt32'],
-                sources = ['keyring/backends/win32_crypto.c'],)
-        exts.append(win32_crypto_module)
-
     return exts

keyring/backend.py

@@ -455,9 +455,9 @@ def __init__(self):
         super(Win32CryptoKeyring, self).__init__()
 
         try:
-            import win32_crypto
+            from backends import win32_crypto
             self.crypt_handler = win32_crypto
-        except ImportError:
+        except ImportError, e:
             self.crypt_handler = None
 
     def filename(self):
@@ -536,7 +536,7 @@ def __init__(self):
         super(Win32CryptoRegistry, self).__init__()
 
         try:
-            import win32_crypto
+            from backends import win32_crypto
             import _winreg
             self.crypt_handler = win32_crypto
         except ImportError:
@@ -599,14 +599,15 @@ def select_windows_backend():
     except ImportError:
         pass
     try:
-        import win32_crypto, _winreg
+        from backends import win32_crypto
+        import _winreg
         if (major, minor) >= (5, 0):
             # recommend for windows 2k+
             return 'reg'
     except ImportError:
         pass
     try:
-        import win32_crypto
+        from backends import win32_crypto
         return 'file'
     except ImportError:
         pass

keyring/backends/win32_crypto.py

@@ -0,0 +1,98 @@
+#!/usr/bin/python
+
+import sys
+if sys.platform != 'win32':
+    raise ImportError('Windows-only module')
+
+
+from ctypes import Structure, wintypes, POINTER, windll, \
+     WinDLL, c_void_p, WINFUNCTYPE, cast, create_string_buffer, \
+     c_char_p, byref, memmove
+
+
+# Crypto API ctypes bindings
+
+class DATA_BLOB(Structure):
+    _fields_ = [('cbData', wintypes.DWORD),
+                ('pbData', POINTER(wintypes.BYTE))]
+
+class CRYPTPROTECT_PROMPTSTRUCT(Structure):
+    _fields_ = [('cbSize', wintypes.DWORD),
+                ('dwPromptFlags', wintypes.DWORD),
+                ('hwndApp', wintypes.HWND),
+                ('szPrompt', POINTER(wintypes.WCHAR))]
+
+# Flags for CRYPTPROTECT_PROMPTSTRUCT
+
+CRYPTPROTECT_PROMPT_ON_UNPROTECT = 1
+CRYPTPROTECT_PROMPT_ON_PROTECT   = 2
+
+# Flags for CryptProtectData/CryptUnprotectData
+
+CRYPTPROTECT_UI_FORBIDDEN      = 0x01
+CRYPTPROTECT_LOCAL_MACHINE     = 0x04
+CRYPTPROTECT_CRED_SYNC         = 0x08
+CRYPTPROTECT_AUDIT             = 0x10
+CRYPTPROTECT_NO_RECOVERY       = 0x20
+CRYPTPROTECT_VERIFY_PROTECTION = 0x40
+CRYPTPROTECT_CRED_REGENERATE   = 0x80
+
+# Crypto API Functions
+
+_dll = WinDLL('CRYPT32.DLL')
+
+CryptProtectData = WINFUNCTYPE(wintypes.BOOL,
+                               POINTER(DATA_BLOB),
+                               POINTER(wintypes.WCHAR),
+                               POINTER(DATA_BLOB),
+                               c_void_p,
+                               POINTER(CRYPTPROTECT_PROMPTSTRUCT),
+                               wintypes.DWORD,
+                               POINTER(DATA_BLOB))(('CryptProtectData', _dll))
+
+CryptUnprotectData = WINFUNCTYPE(wintypes.BOOL,
+                                 POINTER(DATA_BLOB),
+                                 POINTER(wintypes.WCHAR),
+                                 POINTER(DATA_BLOB),
+                                 c_void_p,
+                                 POINTER(CRYPTPROTECT_PROMPTSTRUCT),
+                                 wintypes.DWORD,
+                                 POINTER(DATA_BLOB))(('CryptUnprotectData', _dll))
+
+# Functions
+
+def encrypt(data, non_interactive=0):
+    blobin = DATA_BLOB(cbData=len(data),
+                       pbData=cast(c_char_p(data),
+                                   POINTER(wintypes.BYTE)))
+    blobout = DATA_BLOB()
+
+    if not CryptProtectData(byref(blobin),
+                            u'python-keyring-lib.win32crypto',
+                            None, None, None,
+                            CRYPTPROTECT_UI_FORBIDDEN,
+                            byref(blobout)):
+        raise OSError("Can't encrypt")
+
+    encrypted = create_string_buffer(blobout.cbData)
+    memmove(encrypted, blobout.pbData, blobout.cbData)
+    windll.kernel32.LocalFree(blobout.pbData)
+    return encrypted.raw
+
+def decrypt(encrypted, non_interactive=0):
+    blobin = DATA_BLOB(cbData=len(encrypted),
+                       pbData=cast(c_char_p(encrypted),
+                                   POINTER(wintypes.BYTE)))
+    blobout = DATA_BLOB()
+
+    if not CryptUnprotectData(byref(blobin),
+                              u'python-keyring-lib.win32crypto',
+                              None, None, None,
+                              CRYPTPROTECT_UI_FORBIDDEN,
+                              byref(blobout)):
+        raise OSError("Can't decrypt")
+
+    data = create_string_buffer(blobout.cbData)
+    memmove(data, blobout.pbData, blobout.cbData)
+    windll.kernel32.LocalFree(blobout.pbData)
+    return data.raw

keyring/tests/test_backend.py

@@ -335,7 +335,7 @@ def init_keyring(self):
 
     def supported(self):
         try:
-            import win32_crypto
+            from keyring.backends import win32_crypto
             if sys.platform in ['win32'] and sys.getwindowsversion()[-2] == 2:
                 return 1
         except ImportError: