diff options
| -rw-r--r-- | NEWS | 13 | ||||
| -rw-r--r-- | paramiko/_winapi.py | 269 | ||||
| -rw-r--r-- | paramiko/win_pageant.py | 81 |
3 files changed, 306 insertions, 57 deletions
@@ -12,6 +12,19 @@ Issues noted as "Fabric #NN" can be found at https://github.com/fabric/fabric/. Releases ======== +v1.11.0 (DD MM YYYY) +-------------------- + +* #98: On Windows, when interacting with the PuTTY PAgeant, Paramiko now + creates the shared memory map with explicit Security Attributes of the user, + which is the same technique employed by the canonical PuTTY library to avoid + permissions issues when Paramiko is running under a different UAC context + than the PuTTY Ageant process. Thanks to Jason R. Coombs for the patch. +* #100: Remove use of PyWin32 in `win_pageant` module. Module was already + dependent on ctypes for constructing appropriate structures and had ctypes + implementations of all functionality. Thanks to Jason R. Coombs for the + patch. + v1.10.1 (5th Apr 2013) ---------------------- diff --git a/paramiko/_winapi.py b/paramiko/_winapi.py new file mode 100644 index 00000000..f141b005 --- /dev/null +++ b/paramiko/_winapi.py @@ -0,0 +1,269 @@ +""" +Windows API functions implemented as ctypes functions and classes as found +in jaraco.windows (2.10). + +If you encounter issues with this module, please consider reporting the issues +in jaraco.windows and asking the author to port the fixes back here. +""" + +import ctypes +import ctypes.wintypes +import __builtin__ + +###################### +# jaraco.windows.error + +def format_system_message(errno): + """ + Call FormatMessage with a system error number to retrieve + the descriptive error message. + """ + # first some flags used by FormatMessageW + ALLOCATE_BUFFER = 0x100 + ARGUMENT_ARRAY = 0x2000 + FROM_HMODULE = 0x800 + FROM_STRING = 0x400 + FROM_SYSTEM = 0x1000 + IGNORE_INSERTS = 0x200 + + # Let FormatMessageW allocate the buffer (we'll free it below) + # Also, let it know we want a system error message. + flags = ALLOCATE_BUFFER | FROM_SYSTEM + source = None + message_id = errno + language_id = 0 + result_buffer = ctypes.wintypes.LPWSTR() + buffer_size = 0 + arguments = None + bytes = ctypes.windll.kernel32.FormatMessageW( + flags, + source, + message_id, + language_id, + ctypes.byref(result_buffer), + buffer_size, + arguments, + ) + # note the following will cause an infinite loop if GetLastError + # repeatedly returns an error that cannot be formatted, although + # this should not happen. + handle_nonzero_success(bytes) + message = result_buffer.value + ctypes.windll.kernel32.LocalFree(result_buffer) + return message + + +class WindowsError(__builtin__.WindowsError): + "more info about errors at http://msdn.microsoft.com/en-us/library/ms681381(VS.85).aspx" + + def __init__(self, value=None): + if value is None: + value = ctypes.windll.kernel32.GetLastError() + strerror = format_system_message(value) + super(WindowsError, self).__init__(value, strerror) + + @property + def message(self): + return self.strerror + + @property + def code(self): + return self.winerror + + def __str__(self): + return self.message + + def __repr__(self): + return '{self.__class__.__name__}({self.winerror})'.format(**vars()) + +def handle_nonzero_success(result): + if result == 0: + raise WindowsError() + + +##################### +# jaraco.windows.mmap + +CreateFileMapping = ctypes.windll.kernel32.CreateFileMappingW +CreateFileMapping.argtypes = [ + ctypes.wintypes.HANDLE, + ctypes.c_void_p, + ctypes.wintypes.DWORD, + ctypes.wintypes.DWORD, + ctypes.wintypes.DWORD, + ctypes.wintypes.LPWSTR, +] +CreateFileMapping.restype = ctypes.wintypes.HANDLE + +MapViewOfFile = ctypes.windll.kernel32.MapViewOfFile +MapViewOfFile.restype = ctypes.wintypes.HANDLE + +class MemoryMap(object): + """ + A memory map object which can have security attributes overrideden. + """ + def __init__(self, name, length, security_attributes=None): + self.name = name + self.length = length + self.security_attributes = security_attributes + self.pos = 0 + + def __enter__(self): + p_SA = ( + ctypes.byref(self.security_attributes) + if self.security_attributes else None + ) + INVALID_HANDLE_VALUE = -1 + PAGE_READWRITE = 0x4 + FILE_MAP_WRITE = 0x2 + filemap = ctypes.windll.kernel32.CreateFileMappingW( + INVALID_HANDLE_VALUE, p_SA, PAGE_READWRITE, 0, self.length, + unicode(self.name)) + handle_nonzero_success(filemap) + if filemap == INVALID_HANDLE_VALUE: + raise Exception("Failed to create file mapping") + self.filemap = filemap + self.view = MapViewOfFile(filemap, FILE_MAP_WRITE, 0, 0, 0) + return self + + def seek(self, pos): + self.pos = pos + + def write(self, msg): + ctypes.windll.msvcrt.memcpy(self.view + self.pos, msg, len(msg)) + self.pos += len(msg) + + def read(self, n): + """ + Read n bytes from mapped view. + """ + out = ctypes.create_string_buffer(n) + ctypes.windll.msvcrt.memcpy(out, self.view + self.pos, n) + self.pos += n + return out.raw + + def __exit__(self, exc_type, exc_val, tb): + ctypes.windll.kernel32.UnmapViewOfFile(self.view) + ctypes.windll.kernel32.CloseHandle(self.filemap) + +######################### +# jaraco.windows.security + +class TokenInformationClass: + TokenUser = 1 + +class TOKEN_USER(ctypes.Structure): + num = 1 + _fields_ = [ + ('SID', ctypes.c_void_p), + ('ATTRIBUTES', ctypes.wintypes.DWORD), + ] + + +class SECURITY_DESCRIPTOR(ctypes.Structure): + """ + typedef struct _SECURITY_DESCRIPTOR + { + UCHAR Revision; + UCHAR Sbz1; + SECURITY_DESCRIPTOR_CONTROL Control; + PSID Owner; + PSID Group; + PACL Sacl; + PACL Dacl; + } SECURITY_DESCRIPTOR; + """ + SECURITY_DESCRIPTOR_CONTROL = ctypes.wintypes.USHORT + REVISION = 1 + + _fields_ = [ + ('Revision', ctypes.c_ubyte), + ('Sbz1', ctypes.c_ubyte), + ('Control', SECURITY_DESCRIPTOR_CONTROL), + ('Owner', ctypes.c_void_p), + ('Group', ctypes.c_void_p), + ('Sacl', ctypes.c_void_p), + ('Dacl', ctypes.c_void_p), + ] + +class SECURITY_ATTRIBUTES(ctypes.Structure): + """ + typedef struct _SECURITY_ATTRIBUTES { + DWORD nLength; + LPVOID lpSecurityDescriptor; + BOOL bInheritHandle; + } SECURITY_ATTRIBUTES; + """ + _fields_ = [ + ('nLength', ctypes.wintypes.DWORD), + ('lpSecurityDescriptor', ctypes.c_void_p), + ('bInheritHandle', ctypes.wintypes.BOOL), + ] + + def __init__(self, *args, **kwargs): + super(SECURITY_ATTRIBUTES, self).__init__(*args, **kwargs) + self.nLength = ctypes.sizeof(SECURITY_ATTRIBUTES) + + def _get_descriptor(self): + return self._descriptor + def _set_descriptor(self, descriptor): + self._descriptor = descriptor + self.lpSecurityDescriptor = ctypes.addressof(descriptor) + descriptor = property(_get_descriptor, _set_descriptor) + +def GetTokenInformation(token, information_class): + """ + Given a token, get the token information for it. + """ + data_size = ctypes.wintypes.DWORD() + ctypes.windll.advapi32.GetTokenInformation(token, information_class.num, + 0, 0, ctypes.byref(data_size)) + data = ctypes.create_string_buffer(data_size.value) + handle_nonzero_success(ctypes.windll.advapi32.GetTokenInformation(token, + information_class.num, + ctypes.byref(data), ctypes.sizeof(data), + ctypes.byref(data_size))) + return ctypes.cast(data, ctypes.POINTER(TOKEN_USER)).contents + +class TokenAccess: + TOKEN_QUERY = 0x8 + +def OpenProcessToken(proc_handle, access): + result = ctypes.wintypes.HANDLE() + proc_handle = ctypes.wintypes.HANDLE(proc_handle) + handle_nonzero_success(ctypes.windll.advapi32.OpenProcessToken( + proc_handle, access, ctypes.byref(result))) + return result + +def get_current_user(): + """ + Return a TOKEN_USER for the owner of this process. + """ + process = OpenProcessToken( + ctypes.windll.kernel32.GetCurrentProcess(), + TokenAccess.TOKEN_QUERY, + ) + return GetTokenInformation(process, TOKEN_USER) + +def get_security_attributes_for_user(user=None): + """ + Return a SECURITY_ATTRIBUTES structure with the SID set to the + specified user (uses current user if none is specified). + """ + if user is None: + user = get_current_user() + + assert isinstance(user, TOKEN_USER), "user must be TOKEN_USER instance" + + SD = SECURITY_DESCRIPTOR() + SA = SECURITY_ATTRIBUTES() + # by attaching the actual security descriptor, it will be garbage- + # collected with the security attributes + SA.descriptor = SD + SA.bInheritHandle = 1 + + ctypes.windll.advapi32.InitializeSecurityDescriptor(ctypes.byref(SD), + SECURITY_DESCRIPTOR.REVISION) + ctypes.windll.advapi32.SetSecurityDescriptorOwner(ctypes.byref(SD), + user.SID, 0) + return SA diff --git a/paramiko/win_pageant.py b/paramiko/win_pageant.py index d77d58fe..b96a740f 100644 --- a/paramiko/win_pageant.py +++ b/paramiko/win_pageant.py @@ -21,28 +21,15 @@ Functions for communicating with Pageant, the basic windows ssh agent program. """ -import os +from __future__ import with_statement + import struct -import tempfile -import mmap +import threading import array import platform import ctypes.wintypes -# if you're on windows, you should have one of these, i guess? -# ctypes is part of standard library since Python 2.5 -_has_win32all = False -_has_ctypes = False -try: - # win32gui is preferred over win32ui to avoid MFC dependencies - import win32gui - _has_win32all = True -except ImportError: - try: - import ctypes - _has_ctypes = True - except ImportError: - pass +from . import _winapi _AGENT_COPYDATA_ID = 0x804e50ba _AGENT_MAX_MSGLEN = 8192 @@ -52,16 +39,7 @@ win32con_WM_COPYDATA = 74 def _get_pageant_window_object(): - if _has_win32all: - try: - hwnd = win32gui.FindWindow('Pageant', 'Pageant') - return hwnd - except win32gui.error: - pass - elif _has_ctypes: - # Return 0 if there is no Pageant window. - return ctypes.windll.user32.FindWindowA('Pageant', 'Pageant') - return None + return ctypes.windll.user32.FindWindowA('Pageant', 'Pageant') def can_talk_to_agent(): @@ -71,9 +49,7 @@ def can_talk_to_agent(): This checks both if we have the required libraries (win32all or ctypes) and if there is a Pageant currently running. """ - if (_has_win32all or _has_ctypes) and _get_pageant_window_object(): - return True - return False + return bool(_get_pageant_window_object()) ULONG_PTR = ctypes.c_uint64 if platform.architecture()[0] == '64bit' else ctypes.c_uint32 class COPYDATASTRUCT(ctypes.Structure): @@ -88,48 +64,39 @@ class COPYDATASTRUCT(ctypes.Structure): ] def _query_pageant(msg): + """ + Communication with the Pageant process is done through a shared + memory-mapped file. + """ hwnd = _get_pageant_window_object() if not hwnd: # Raise a failure to connect exception, pageant isn't running anymore! return None - # Write our pageant request string into the file (pageant will read this to determine what to do) - filename = tempfile.mktemp('.pag') - map_filename = os.path.basename(filename) - - f = open(filename, 'w+b') - f.write(msg ) - # Ensure the rest of the file is empty, otherwise pageant will read this - f.write('\0' * (_AGENT_MAX_MSGLEN - len(msg))) - # Create the shared file map that pageant will use to read from - pymap = mmap.mmap(f.fileno(), _AGENT_MAX_MSGLEN, tagname=map_filename, access=mmap.ACCESS_WRITE) - try: + # create a name for the mmap + map_name = 'PageantRequest%08x' % threading.current_thread().ident + + pymap = _winapi.MemoryMap(map_name, _AGENT_MAX_MSGLEN, + _winapi.get_security_attributes_for_user(), + ) + with pymap: + pymap.write(msg) # Create an array buffer containing the mapped filename - char_buffer = array.array("c", map_filename + '\0') + char_buffer = array.array("c", map_name + '\0') char_buffer_address, char_buffer_size = char_buffer.buffer_info() # Create a string to use for the SendMessage function call - cds = COPYDATASTRUCT(_AGENT_COPYDATA_ID, char_buffer_size, char_buffer_address) + cds = COPYDATASTRUCT(_AGENT_COPYDATA_ID, char_buffer_size, + char_buffer_address) - if _has_win32all: - # win32gui.SendMessage should also allow the same pattern as - # ctypes, but let's keep it like this for now... - response = win32gui.SendMessage(hwnd, win32con_WM_COPYDATA, ctypes.sizeof(cds), ctypes.addressof(cds)) - elif _has_ctypes: - response = ctypes.windll.user32.SendMessageA(hwnd, win32con_WM_COPYDATA, ctypes.sizeof(cds), ctypes.byref(cds)) - else: - response = 0 + response = ctypes.windll.user32.SendMessageA(hwnd, + win32con_WM_COPYDATA, ctypes.sizeof(cds), ctypes.byref(cds)) if response > 0: + pymap.seek(0) datalen = pymap.read(4) retlen = struct.unpack('>I', datalen)[0] return datalen + pymap.read(retlen) return None - finally: - pymap.close() - f.close() - # Remove the file, it was temporary only - os.unlink(filename) - class PageantConnection (object): """ |