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sslcontext.py
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from ctypes import *
import ctypes
from ctypes.wintypes import *
from _ssl import SSLError
import sys
CRYPT32 = windll.Crypt32
SCHANNEL = windll.SChannel
# Lots of "Magic" constants, mainly from schannel.h
SCH_CRED_NO_SYSTEM_MAPPER = 0x00000002
SCH_CRED_NO_DEFAULT_CREDS = 0x00000010
SCH_CRED_REVOCATION_CHECK_CHAIN = 0x00000200
SCH_CRED_REVOCATION_CHECK_CHAIN_EXCLUDE_ROOT = 0x00000400
SCH_CRED_IGNORE_NO_REVOCATION_CHECK = 0x00000800
SECPKG_ATTR_REMOTE_CERT_CONTEXT = 0x53
SECPKG_ATTR_STREAM_SIZES = 4
SP_PROT_SSL3_CLIENT = 0x00000020
SP_PROT_SSL2_CLIENT = 0x00000008
SP_PROT_TLS1_1_CLIENT = 0x00000200
SCHANNEL_CRED_VERSION = 0x00000004
UNISP_NAME = "Microsoft Unified Security Protocol Provider"
SECPKG_CRED_OUTBOUND = 0x00000002
SECURITY_NATIVE_DREP = 0x00000010
SECBUFFER_VERSION = 0
SECBUFFER_EMPTY = 0
SECBUFFER_DATA = 1
SECBUFFER_TOKEN = 2
SECBUFFER_EXTRA = 5
SECBUFFER_STREAM_TRAILER = 6
SECBUFFER_STREAM_HEADER = 7
ISC_REQ_SEQUENCE_DETECT = 0x00000008
ISC_REQ_REPLAY_DETECT = 0x00000004
ISC_REQ_CONFIDENTIALITY = 0x00000010
ISC_REQ_EXTENDED_ERROR = 0x00008000
ISC_REQ_ALLOCATE_MEMORY = 0x00000100
ISC_REQ_STREAM = 0x00010000
SEC_I_CONTINUE_NEEDED = 0x00090312
SEC_I_INCOMPLETE_CREDENTIALS = 0x00090320
SEC_I_RENEGOTIATE = 0x00090321
SEC_E_INCOMPLETE_MESSAGE = 0x80090318
SEC_E_INTERNAL_ERROR = 0x80090304
SEC_E_OK = 0x00000000
class SecPkgContext_StreamSizes(Structure):
_fields_ = [("cbHeader", ULONG),
("cbTrailer", ULONG),
("cbMaximumMessage", ULONG),
("cBuffers", ULONG),
("cbBlockSize", ULONG)]
class CERT_CONTEXT(Structure):
_fields_ = [("dwCertEncodingType", DWORD),
("pbCertEncoded", c_char_p),
("cbCertEncoded", DWORD),
("pCertInfo", c_void_p),
("hCertStore", c_void_p)]
class SecBuffer(Structure):
_fields_ = [("cbBuffer", ULONG),
("BufferType", ULONG),
("pvBuffer", c_void_p)]
class SecBufferDesc(Structure):
_fields_ = [("ulVersion", ULONG),
("cBuffers", ULONG),
("pBuffers", POINTER(SecBuffer))]
class _SecHandle(Structure):
_fields_ = [("dwLower", ULONG ),
("dwUpper", ULONG )]
class SCHANNEL_CRED(Structure):
_fields_ = [("dwVersion", DWORD),
("cCreds", DWORD),
("paCred", POINTER(HANDLE)),
("hRootStore", HANDLE),
("cMappers", DWORD),
("aphMappers", POINTER(HANDLE)),
("cSupportedAlgs", DWORD),
("palgSupportedAlgs", POINTER(HANDLE)),
("grbitEnabledProtocols", DWORD),
("dwMinimumCipherStrength", DWORD),
("dwMaximumCipherStrength", DWORD),
("dwSessionLifespan", DWORD),
("dwFlags", DWORD),
("dwCredFormat", DWORD),
]
class SecurityFunctionTable(Structure):
_fields_ = [("dwVersion", ULONG),
("EnumerateSecurityPackages", WINFUNCTYPE(LONG)),
("QueryCredentialsAttributes", WINFUNCTYPE(LONG)),
("AcquireCredentialsHandle", WINFUNCTYPE(ULONG, c_void_p, c_wchar_p, ULONG, HANDLE, c_void_p, c_void_p, c_void_p, HANDLE, PULONG)),
("FreeCredentialsHandle", WINFUNCTYPE(LONG)),
("Reserved2", c_void_p),
("InitializeSecurityContext", WINFUNCTYPE(ULONG, c_void_p, c_void_p, c_wchar_p, ULONG, ULONG, ULONG, c_void_p, ULONG, c_void_p, c_void_p, POINTER(ULONG), POINTER(ULONG))),
("AcceptSecurityContext", WINFUNCTYPE(ULONG)),
("CompleteAuthToken", WINFUNCTYPE(LONG)),
("DeleteSecurityContext", WINFUNCTYPE(LONG, c_void_p)),
("ApplyControlToken", WINFUNCTYPE(LONG)),
("QueryContextAttributes", WINFUNCTYPE(LONG, c_void_p, ULONG, c_void_p)),
("ImpersonateSecurityContext", WINFUNCTYPE(LONG)),
("RevertSecurityContext", WINFUNCTYPE(LONG)),
("MakeSignature", WINFUNCTYPE(LONG)),
("VerifySignature", WINFUNCTYPE(LONG)),
("FreeContextBuffer", WINFUNCTYPE(LONG, c_void_p)),
("QuerySecurityPackageInfo", WINFUNCTYPE(LONG)),
("Reserved3", c_void_p),
("Reserved4", c_void_p),
("ExportSecurityContext", WINFUNCTYPE(LONG)),
("ImportSecurityContext", WINFUNCTYPE(LONG)),
("AddCredentials", WINFUNCTYPE(LONG)),
("Reserved8", c_void_p),
("QuerySecurityContextToken", WINFUNCTYPE(LONG)),
("EncryptMessage", WINFUNCTYPE(ULONG, HANDLE, ULONG, HANDLE, ULONG)),
("DecryptMessage", WINFUNCTYPE(ULONG, HANDLE, HANDLE, ULONG, PULONG)),
("SetContextAttributes", WINFUNCTYPE(LONG)),]
class SSLContext(object):
def __init__(self):
self._InitSecurityInterface()
self._creds = None
self._context = _SecHandle()
self._SchannelCred = None
self.reset()
def reset(self):
if self._creds is not None:
windll.Secur32.FreeCredentialsHandle(byref(self._creds))
self._creds = _SecHandle()
self._creds.dwUpper = 0;
self._creds.dwLower = 0;
self._context.dwUpper = 0;
self._context.dwLower = 0;
self._SchannelCred = SCHANNEL_CRED()
self._intialized = False
self._recv_buffer = b'' # Raw socket data
self._recv_buffer_decrypted = b'' # socket data that is decrypted
def do_handshake(self):
self.reset()
self._ClientCreateCredentials()
self._ClientHandshake()
#TODO: validate remote certificate
self._intialized = True #all communications should now be encrypted
def _ClientHandshake(self):
buffer = SecBuffer()
buffer.pvBuffer = None
buffer.BufferType = SECBUFFER_TOKEN
buffer.cbBuffer = 0
bufferGroup = SecBufferDesc()
bufferGroup.cBuffers = 1
bufferGroup.pBuffers = pointer(buffer)
bufferGroup.ulVersion = SECBUFFER_VERSION
dwSSPIFlags = ISC_REQ_SEQUENCE_DETECT | ISC_REQ_REPLAY_DETECT | ISC_REQ_CONFIDENTIALITY | ISC_REQ_EXTENDED_ERROR | ISC_REQ_ALLOCATE_MEMORY | ISC_REQ_STREAM
dwSSPIOutFlags = DWORD()
Status = self._securityFunc.InitializeSecurityContext(byref(self._creds),
None,
c_wchar_p(self._server_hostname),
dwSSPIFlags,
0,
SECURITY_NATIVE_DREP,
None,
0,
byref(self._context),
byref(bufferGroup),
byref(dwSSPIOutFlags),
POINTER(ULONG)() )
if Status != SEC_I_CONTINUE_NEEDED and Status != SEC_E_OK:
raise SSLError(WinError(c_long(Status).value))
if Status == SEC_I_CONTINUE_NEEDED:
if buffer.cbBuffer != 0 and buffer.pvBuffer is not None:
data = string_at(buffer.pvBuffer, buffer.cbBuffer)
if self.send(data, plaintext = True) == 0:
self._securityFunc.FreeContextBuffer(buffer.pvBuffer)
self._securityFunc.DeleteSecurityContext(byref(self._context))
else:
self._securityFunc.FreeContextBuffer(buffer.pvBuffer)
(Status,extraData) = self._ClientHandshakeLoop(True)
if Status != SEC_E_OK:
raise SSLError(WinError(c_long(Status).value))
def _ClientHandshakeLoop(self, doRead):
Status = SEC_I_CONTINUE_NEEDED
dwSSPIFlags = ISC_REQ_SEQUENCE_DETECT | ISC_REQ_REPLAY_DETECT | ISC_REQ_CONFIDENTIALITY | ISC_REQ_EXTENDED_ERROR | ISC_REQ_ALLOCATE_MEMORY | ISC_REQ_STREAM
dwSSPIOutFlags = DWORD()
recv_data = b''
while Status == SEC_I_CONTINUE_NEEDED or Status == SEC_E_INCOMPLETE_MESSAGE or Status == SEC_I_INCOMPLETE_CREDENTIALS:
if len(recv_data) == 0 or Status == SEC_E_INCOMPLETE_MESSAGE:
if doRead:
data = self._sock.recv(2048, raw = True)
recv_data += data
else:
doRead = True
inBufferGroup = SecBufferDesc()
inBufferGroup.cBuffers = 2
inBufferGroup.ulVersion = SECBUFFER_VERSION
buffers = (SecBuffer * 2)()
buffers[0].pvBuffer = cast(c_char_p(recv_data), c_void_p)
buffers[0].cbBuffer = len(recv_data)
buffers[0].BufferType = SECBUFFER_TOKEN
buffers[1].pvBuffer = None
buffers[1].cbBuffers = 0
buffers[1].BufferType = SECBUFFER_EMPTY
inBufferGroup.pBuffers = buffers
outBufferGroup = SecBufferDesc()
outBufferGroup.cBuffers = 1
outBufferGroup.ulVersion = SECBUFFER_VERSION
buffers = (SecBuffer * 1)()
buffers[0].pvBuffer = None
buffers[0].BufferType = SECBUFFER_TOKEN
buffers[0].cbBuffer = 0
outBufferGroup.pBuffers = buffers
Status = self._securityFunc.InitializeSecurityContext(byref(self._creds),
byref(self._context),
c_wchar_p(self._server_hostname),
dwSSPIFlags,
0,
SECURITY_NATIVE_DREP,
byref(inBufferGroup),
0,
None,
byref(outBufferGroup),
byref(dwSSPIOutFlags),
POINTER(ULONG)()
)
if Status == SEC_E_OK or Status == SEC_I_CONTINUE_NEEDED:
if outBufferGroup.pBuffers[0].cbBuffer != 0 and outBufferGroup.pBuffers[0].pvBuffer is not None:
data = string_at(outBufferGroup.pBuffers[0].pvBuffer, outBufferGroup.pBuffers[0].cbBuffer)
if self._sock.sendall(data, raw = True) == 0:
self._securityFunc.FreeContextBuffer(outBufferGroup.pBuffers[0].pvBuffer)
self._securityFunc.DeleteSecurityContext(byref(self._context))
return (SEC_E_INTERNAL_ERROR, None)
else:
self._securityFunc.FreeContextBuffer(outBufferGroup.pBuffers[0].pvBuffer)
outBufferGroup.pBuffers[0].pvBuffer = None
if Status == SEC_E_INCOMPLETE_MESSAGE:
continue
if Status == SEC_E_OK:
if inBufferGroup.pBuffers[1].BufferType == SECBUFFER_EXTRA:
return (Status, recv_data[-inBufferGroup.pBuffers[1].cbBuffer:])
else:
return (Status, None)
if inBufferGroup.pBuffers[1].BufferType == SECBUFFER_EXTRA:
recv_data = recv_data[-inBufferGroup.pBuffers[1].cbBuffer:]
else:
recv_data = b""
if Status == SEC_I_INCOMPLETE_CREDENTIALS:
#return (Status, None)
doRead = False
continue
return (Status, None)
def _InitSecurityInterface(self):
func = SCHANNEL.InitSecurityInterfaceW
func.restype = POINTER(SecurityFunctionTable)
self._securityFunc = func().contents
def _wrap_socket(self, sock, server_side, server_hostname, client_certificate = None):
self._sock = sock
self._server_hostname = server_hostname
self._client_certificate = client_certificate
return self
def _ClientCreateCredentials(self):
if self._client_certificate is not None:
self._SchannelCred.cCreds = 1
self._SchannelCred.paCred = pointer(self._client_certificate)
self._SchannelCred.grbitEnabledProtocols = SP_PROT_TLS1_1_CLIENT #| SP_PROT_TLS1_1_CLIENT | SP_PROT_SSL2_CLIENT
self._SchannelCred.dwVersion = SCHANNEL_CRED_VERSION
self._SchannelCred.dwFlags |= SCH_CRED_NO_DEFAULT_CREDS | \
SCH_CRED_NO_SYSTEM_MAPPER | \
SCH_CRED_REVOCATION_CHECK_CHAIN_EXCLUDE_ROOT | \
SCH_CRED_IGNORE_NO_REVOCATION_CHECK
Status = self._securityFunc.AcquireCredentialsHandle(None,
c_wchar_p(UNISP_NAME),
SECPKG_CRED_OUTBOUND,
None,
byref(self._SchannelCred),
None,
None,
byref(self._creds),
POINTER(ULONG)())
if Status != SEC_E_OK:
raise SSLError(WinError(Status))
def send(self, data, flags = 0, plaintext = False):
if self._intialized is False and plaintext is True:
return self._sock.sendall(data, flags, raw = True)
else:
Sizes = SecPkgContext_StreamSizes()
Status = self._securityFunc.QueryContextAttributes(byref(self._context), SECPKG_ATTR_STREAM_SIZES, byref(Sizes))
if Status != SEC_E_OK:
raise SSLError(WinError(c_long(Status).value))
bufferValue = b'\x00' * Sizes.cbHeader + data + b'\x00' * Sizes.cbTrailer + (b'\x00' *(Sizes.cbMaximumMessage - len(data)))
allocatedBuffer = create_string_buffer(bufferValue)
messageBuffers = SecBufferDesc()
messageBuffers.cBuffers = 4
messageBuffers.ulVersion = SECBUFFER_VERSION
buffers = (SecBuffer * 4)()
buffers[0].BufferType = SECBUFFER_STREAM_HEADER
buffers[0].cbBuffer = Sizes.cbHeader
buffers[0].pvBuffer = cast(byref(allocatedBuffer), c_void_p)
buffers[1].BufferType = SECBUFFER_DATA
buffers[1].cbBuffer = len(data)
buffers[1].pvBuffer = cast(byref(allocatedBuffer, Sizes.cbHeader), c_void_p)
buffers[2].BufferType = SECBUFFER_STREAM_TRAILER
buffers[2].cbBuffer = Sizes.cbTrailer
buffers[2].pvBuffer = cast(byref(allocatedBuffer, Sizes.cbHeader + len(data)), c_void_p)
buffers[3].BufferType = SECBUFFER_EMPTY
messageBuffers.pBuffers = buffers
Status = self._securityFunc.EncryptMessage(byref(self._context),0, byref(messageBuffers), 0)
if Status != SEC_E_OK:
raise SSLError(WinError(c_long(Status).value))
encrypted_data = string_at(buffers[0].pvBuffer, buffers[0].cbBuffer + buffers[1].cbBuffer + buffers[2].cbBuffer)
return self._sock.sendall(encrypted_data, flags, raw=True)
def recv(self, buffersize, flags=0, plaintext=False):
if self._intialized is False and plaintext is True:
return self._sock.recv(buffersize, flags, raw=True)
else:
if len(self._recv_buffer_decrypted) > 0:
decrypted_data = self._recv_buffer_decrypted[:buffersize]
self._recv_buffer_decrypted = self._recv_buffer_decrypted[buffersize:]
return decrypted_data
decrypted_data = self._recv_buffer_decrypted
shouldContinue = True
while shouldContinue:
self._recv_buffer += self._sock.recv(buffersize, flags, raw = True)
messageBuffers = SecBufferDesc()
messageBuffers.cBuffers = 4
messageBuffers.ulVersion = SECBUFFER_VERSION
buffers = (SecBuffer * 4)()
buffers[0].pvBuffer = cast(c_char_p(self._recv_buffer), c_void_p)
buffers[0].cbBuffer = len(self._recv_buffer)
buffers[0].BufferType = SECBUFFER_DATA
buffers[1].BufferType = SECBUFFER_EMPTY
buffers[2].BufferType = SECBUFFER_EMPTY
buffers[3].BufferType = SECBUFFER_EMPTY
messageBuffers.pBuffers = buffers
Status = self._securityFunc.DecryptMessage(byref(self._context), byref(messageBuffers), 0, None)
if Status == SEC_E_INCOMPLETE_MESSAGE:
continue
if Status != SEC_E_OK and Status != SEC_I_RENEGOTIATE:
raise SSLError(WinError(c_long(Status).value))
for idx in range(1,4):
if messageBuffers.pBuffers[idx].BufferType == SECBUFFER_DATA:
decrypted_data += string_at(messageBuffers.pBuffers[idx].pvBuffer, messageBuffers.pBuffers[idx].cbBuffer)
break
extra_data = b''
for idx in range(1,4):
if messageBuffers.pBuffers[idx].BufferType == SECBUFFER_EXTRA:
extra_data = string_at(messageBuffers.pBuffers[idx].pvBuffer, messageBuffers.pBuffers[idx].cbBuffer)
break
if len(extra_data) > 0:
self._recv_buffer = extra_data
continue
else:
self._recv_buffer = b''
shouldContinue = False
if Status == SEC_I_RENEGOTIATE:
(Status, _) = self._ClientHandshakeLoop(doRead = False)
shouldContinue = True
if Status != SEC_E_OK:
raise SSLError(WinError(c_long(Status).value))
elif Status != SEC_E_OK:
raise SSLError(WinError(c_long(Status).value))
self._recv_buffer_decrypted = decrypted_data[buffersize:]
return decrypted_data[:buffersize]