Add support for CredEnumerate (#111)

* Add code for CredEnumerate in the cffi backend (based on Add CredEnumerate function #109)
* Add code for CredEnumerate in ctypes
* Cleanup code a little bit
* Add tests for CredEnumerate
fixes #110

Author: itziakos

setup.py

@@ -8,7 +8,7 @@
 
 filename = os.path.join(HERE, 'win32ctypes', 'version.py')
 with open(filename, 'w') as handle:
-    handle.write('__version__="%s"\n' % version)
+    handle.write(f'__version__ = "{version}"\n')
 
 setup(
     name='pywin32-ctypes',

win32ctypes/core/cffi/_authentication.py

@@ -8,7 +8,7 @@
 from weakref import WeakKeyDictionary
 
 from win32ctypes.core.compat import is_text
-from ._util import ffi, check_zero, dlls
+from ._util import ffi, check_false, dlls
 from ._nl_support import _GetACP
 from ._common import _PyBytes_FromStringAndSize
 
@@ -48,7 +48,8 @@
 BOOL WINAPI CredWriteW(PCREDENTIAL Credential, DWORD);
 VOID WINAPI CredFree(PVOID Buffer);
 BOOL WINAPI CredDeleteW(LPCWSTR TargetName, DWORD Type, DWORD Flags);
-
+BOOL WINAPI CredEnumerateW(
+    LPCWSTR Filter, DWORD Flags, DWORD *Count, PCREDENTIAL **Credential);
 """)
 
 _keep_alive = WeakKeyDictionary()
@@ -120,6 +121,10 @@ def PPCREDENTIAL(value=None):
     return ffi.new("PCREDENTIAL*", ffi.NULL if value is None else value)
 
 
+def PPPCREDENTIAL(value=None):
+    return ffi.new("PCREDENTIAL**", ffi.NULL if value is None else value)
+
+
 def credential2dict(pc_creds):
     credentials = {}
     for key in SUPPORTED_CREDKEYS:
@@ -140,21 +145,27 @@ def credential2dict(pc_creds):
 
 def _CredRead(TargetName, Type, Flags, ppCredential):
     target = make_unicode(TargetName)
-    value = check_zero(
+    return check_false(
         dlls.advapi32.CredReadW(target, Type, Flags, ppCredential),
         u'CredRead')
-    return value
 
 
 def _CredWrite(Credential, Flags):
-    return check_zero(
+    return check_false(
         dlls.advapi32.CredWriteW(Credential, Flags), u'CredWrite')
 
 
 def _CredDelete(TargetName, Type, Flags):
-    return check_zero(
+    return check_false(
         dlls.advapi32.CredDeleteW(
             make_unicode(TargetName), Type, Flags), u'CredDelete')
 
 
+def _CredEnumerate(Filter, Flags, Count, pppCredential):
+    filter = make_unicode(Filter) if Filter is not None else ffi.NULL
+    return check_false(
+        dlls.advapi32.CredEnumerateW(filter, Flags, Count, pppCredential),
+        u'CredEnumerate')
+
+
 _CredFree = dlls.advapi32.CredFree

win32ctypes/core/cffi/_common.py

@@ -23,3 +23,7 @@ def byreference(x):
 
 def dereference(x):
     return x[0]
+
+
+def PDWORD(value=0):
+    return ffi.new("DWORD *", value)

win32ctypes/core/ctypes/_authentication.py

@@ -11,8 +11,8 @@
     BOOL, DWORD, FILETIME, LPCWSTR)
 
 from win32ctypes.core.compat import is_text
-from ._common import LPBYTE, _PyBytes_FromStringAndSize
-from ._util import function_factory, check_zero_factory, dlls
+from ._common import LPBYTE, _PyBytes_FromStringAndSize, PDWORD
+from ._util import function_factory, check_false_factory, dlls
 from ._nl_support import _GetACP
 
 
@@ -67,17 +67,19 @@ def fromdict(cls, credential, flags=0):
 
 
 PCREDENTIAL = POINTER(CREDENTIAL)
+PPCREDENTIAL = POINTER(PCREDENTIAL)
+PPPCREDENTIAL = POINTER(PPCREDENTIAL)
 
 
-def make_unicode(password):
+def make_unicode(text):
     """ Convert the input string to unicode.
 
     """
-    if is_text(password):
-        return password
+    if is_text(text):
+        return text
     else:
         code_page = _GetACP()
-        return password.decode(encoding=str(code_page), errors='strict')
+        return text.decode(encoding=str(code_page), errors='strict')
 
 
 def credential2dict(creds):
@@ -93,22 +95,33 @@ def credential2dict(creds):
     return credential
 
 
+def _CredEnumerate(Filter, Flags, Count, pppCredential):
+    filter_ = LPCWSTR(Filter)
+    _BaseCredEnumerate(filter_, Flags, Count, pppCredential)
+
+
 _CredWrite = function_factory(
     dlls.advapi32.CredWriteW,
     [PCREDENTIAL, DWORD],
     BOOL,
-    check_zero_factory("CredWrite"))
+    check_false_factory("CredWrite"))
 
 _CredRead = function_factory(
     dlls.advapi32.CredReadW,
-    [LPCWSTR, DWORD, DWORD, POINTER(PCREDENTIAL)],
+    [LPCWSTR, DWORD, DWORD, PPCREDENTIAL],
     BOOL,
-    check_zero_factory("CredRead"))
+    check_false_factory("CredRead"))
 
 _CredDelete = function_factory(
     dlls.advapi32.CredDeleteW,
     [LPCWSTR, DWORD, DWORD],
     BOOL,
-    check_zero_factory("CredDelete"))
+    check_false_factory("CredDelete"))
+
+_BaseCredEnumerate = function_factory(
+    dlls.advapi32.CredEnumerateW,
+    [LPCWSTR, DWORD, PDWORD, PPPCREDENTIAL],
+    BOOL,
+    check_false_factory("CredEnumerate"))
 
 _CredFree = function_factory(dlls.advapi32.CredFree, [PCREDENTIAL])

win32ctypes/pywin32/pywintypes.py

@@ -32,4 +32,6 @@ def pywin32error():
     try:
         yield
     except WindowsError as exception:
+        if not hasattr(exception, 'function'):
+            exception.function = 'unknown'
         raise error(exception.winerror, exception.function, exception.strerror)

win32ctypes/pywin32/win32cred.py

@@ -14,6 +14,7 @@
 CRED_PERSIST_LOCAL_MACHINE = 0x2
 CRED_PERSIST_ENTERPRISE = 0x3
 CRED_PRESERVE_CREDENTIAL_BLOB = 0
+CRED_ENUMERATE_ALL_CREDENTIALS = 0x1
 
 
 def CredWrite(Credential, Flags=CRED_PRESERVE_CREDENTIAL_BLOB):
@@ -89,3 +90,49 @@ def CredDelete(TargetName, Type, Flags=0):
         raise ValueError("Type != CRED_TYPE_GENERIC not yet supported.")
     with _pywin32error():
         _authentication._CredDelete(TargetName, Type, 0)
+
+
+def CredEnumerate(Filter=None, Flags=0):
+    """ Remove the given target name from the stored credentials.
+
+    Parameters
+    ----------
+    Filter : unicode
+        Matches credentials' target names by prefix, can be None.
+    Flags : int
+        When set to CRED_ENUMERATE_ALL_CREDENTIALS enumerates all of
+        the credentials in the user's credential set but in that
+        case the Filter parameter should be NULL, an error is
+        raised otherwise
+
+    Returns
+    -------
+    credentials : list
+        Returns a sequence of CREDENTIAL dictionaries.
+
+    """
+    with _pywin32error():
+        if _backend == 'cffi':
+            pcount = _common.PDWORD()
+            pppcreds = _authentication.PPPCREDENTIAL()
+            _authentication._CredEnumerate(Filter, Flags, pcount, pppcreds)
+            count = pcount[0]
+            pcreds = _common.dereference(
+                _common.ffi.cast(f"PCREDENTIAL*[{count}]", pppcreds))
+        else:
+            import ctypes
+            count = ctypes.DWORD()
+            # Create a mutable pointer variable
+            mem = ctypes.create_string_buffer(1)
+            pppcreds = _common.cast(
+                mem, _authentication.PPPCREDENTIAL)
+            _authentication._CredEnumerate(
+                Filter, Flags, _common.byreference(count), pppcreds)
+            count = count.value
+            pcreds = _common.dereference(_common.dereference(pppcreds))
+    try:
+        return [
+            _authentication.credential2dict(pcreds[i])
+            for i in range(count)]
+    finally:
+        _authentication._CredFree(pcreds)