paramiko/paramiko/_winapi.py

279 lines
8.1 KiB
Python

"""
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
from paramiko.py3compat import u
try:
import builtins
except ImportError:
import __builtin__ as builtins
try:
USHORT = ctypes.wintypes.USHORT
except AttributeError:
USHORT = ctypes.c_ushort
######################
# 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
format_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(format_bytes)
message = result_buffer.value
ctypes.windll.kernel32.LocalFree(result_buffer)
return message
class WindowsError(builtins.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()
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,
u(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):
n = len(msg)
if self.pos + n >= self.length: # A little safety.
raise ValueError("Refusing to write %d bytes" % n)
ctypes.windll.kernel32.RtlMoveMemory(self.view + self.pos, msg, n)
self.pos += n
def read(self, n):
"""
Read n bytes from mapped view.
"""
out = ctypes.create_string_buffer(n)
ctypes.windll.kernel32.RtlMoveMemory(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 = 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