435
479
.format(self.name)))
482
# Pretend that we have a GnuTLS module
483
class GnuTLS(object):
484
"""This isn't so much a class as it is a module-like namespace.
485
It is instantiated once, and simulates having a GnuTLS module."""
487
_library = ctypes.cdll.LoadLibrary(
488
ctypes.util.find_library("gnutls"))
489
_need_version = b"3.3.0"
491
# Need to use class name "GnuTLS" here, since this method is
492
# called before the assignment to the "gnutls" global variable
494
if GnuTLS.check_version(self._need_version) is None:
495
raise GnuTLS.Error("Needs GnuTLS {} or later"
496
.format(self._need_version))
498
# Unless otherwise indicated, the constants and types below are
499
# all from the gnutls/gnutls.h C header file.
509
E_NO_CERTIFICATE_FOUND = -49
510
OPENPGP_FMT_RAW = 0 # gnutls/openpgp.h
513
class session_int(ctypes.Structure):
515
session_t = ctypes.POINTER(session_int)
516
class certificate_credentials_st(ctypes.Structure):
518
certificate_credentials_t = ctypes.POINTER(
519
certificate_credentials_st)
520
certificate_type_t = ctypes.c_int
521
class datum_t(ctypes.Structure):
522
_fields_ = [('data', ctypes.POINTER(ctypes.c_ubyte)),
523
('size', ctypes.c_uint)]
524
class openpgp_crt_int(ctypes.Structure):
526
openpgp_crt_t = ctypes.POINTER(openpgp_crt_int)
527
openpgp_crt_fmt_t = ctypes.c_int # gnutls/openpgp.h
528
log_func = ctypes.CFUNCTYPE(None, ctypes.c_int, ctypes.c_char_p)
529
credentials_type_t = ctypes.c_int
530
transport_ptr_t = ctypes.c_void_p
531
close_request_t = ctypes.c_int
534
class Error(Exception):
535
# We need to use the class name "GnuTLS" here, since this
536
# exception might be raised from within GnuTLS.__init__,
537
# which is called before the assignment to the "gnutls"
538
# global variable has happened.
539
def __init__(self, message = None, code = None, args=()):
540
# Default usage is by a message string, but if a return
541
# code is passed, convert it to a string with
544
if message is None and code is not None:
545
message = GnuTLS.strerror(code)
546
return super(GnuTLS.Error, self).__init__(
549
class CertificateSecurityError(Error):
553
class Credentials(object):
555
self._c_object = gnutls.certificate_credentials_t()
556
gnutls.certificate_allocate_credentials(
557
ctypes.byref(self._c_object))
558
self.type = gnutls.CRD_CERTIFICATE
561
gnutls.certificate_free_credentials(self._c_object)
563
class ClientSession(object):
564
def __init__(self, socket, credentials = None):
565
self._c_object = gnutls.session_t()
566
gnutls.init(ctypes.byref(self._c_object), gnutls.CLIENT)
567
gnutls.set_default_priority(self._c_object)
568
gnutls.transport_set_ptr(self._c_object, socket.fileno())
569
gnutls.handshake_set_private_extensions(self._c_object,
572
if credentials is None:
573
credentials = gnutls.Credentials()
574
gnutls.credentials_set(self._c_object, credentials.type,
575
ctypes.cast(credentials._c_object,
577
self.credentials = credentials
580
gnutls.deinit(self._c_object)
583
return gnutls.handshake(self._c_object)
585
def send(self, data):
589
data_len -= gnutls.record_send(self._c_object,
594
return gnutls.bye(self._c_object, gnutls.SHUT_RDWR)
596
# Error handling functions
597
def _error_code(result):
598
"""A function to raise exceptions on errors, suitable
599
for the 'restype' attribute on ctypes functions"""
602
if result == gnutls.E_NO_CERTIFICATE_FOUND:
603
raise gnutls.CertificateSecurityError(code = result)
604
raise gnutls.Error(code = result)
606
def _retry_on_error(result, func, arguments):
607
"""A function to retry on some errors, suitable
608
for the 'errcheck' attribute on ctypes functions"""
610
if result not in (gnutls.E_INTERRUPTED, gnutls.E_AGAIN):
611
return _error_code(result)
612
result = func(*arguments)
615
# Unless otherwise indicated, the function declarations below are
616
# all from the gnutls/gnutls.h C header file.
619
priority_set_direct = _library.gnutls_priority_set_direct
620
priority_set_direct.argtypes = [session_t, ctypes.c_char_p,
621
ctypes.POINTER(ctypes.c_char_p)]
622
priority_set_direct.restype = _error_code
624
init = _library.gnutls_init
625
init.argtypes = [ctypes.POINTER(session_t), ctypes.c_int]
626
init.restype = _error_code
628
set_default_priority = _library.gnutls_set_default_priority
629
set_default_priority.argtypes = [session_t]
630
set_default_priority.restype = _error_code
632
record_send = _library.gnutls_record_send
633
record_send.argtypes = [session_t, ctypes.c_void_p,
635
record_send.restype = ctypes.c_ssize_t
636
record_send.errcheck = _retry_on_error
638
certificate_allocate_credentials = (
639
_library.gnutls_certificate_allocate_credentials)
640
certificate_allocate_credentials.argtypes = [
641
ctypes.POINTER(certificate_credentials_t)]
642
certificate_allocate_credentials.restype = _error_code
644
certificate_free_credentials = (
645
_library.gnutls_certificate_free_credentials)
646
certificate_free_credentials.argtypes = [certificate_credentials_t]
647
certificate_free_credentials.restype = None
649
handshake_set_private_extensions = (
650
_library.gnutls_handshake_set_private_extensions)
651
handshake_set_private_extensions.argtypes = [session_t,
653
handshake_set_private_extensions.restype = None
655
credentials_set = _library.gnutls_credentials_set
656
credentials_set.argtypes = [session_t, credentials_type_t,
658
credentials_set.restype = _error_code
660
strerror = _library.gnutls_strerror
661
strerror.argtypes = [ctypes.c_int]
662
strerror.restype = ctypes.c_char_p
664
certificate_type_get = _library.gnutls_certificate_type_get
665
certificate_type_get.argtypes = [session_t]
666
certificate_type_get.restype = _error_code
668
certificate_get_peers = _library.gnutls_certificate_get_peers
669
certificate_get_peers.argtypes = [session_t,
670
ctypes.POINTER(ctypes.c_uint)]
671
certificate_get_peers.restype = ctypes.POINTER(datum_t)
673
global_set_log_level = _library.gnutls_global_set_log_level
674
global_set_log_level.argtypes = [ctypes.c_int]
675
global_set_log_level.restype = None
677
global_set_log_function = _library.gnutls_global_set_log_function
678
global_set_log_function.argtypes = [log_func]
679
global_set_log_function.restype = None
681
deinit = _library.gnutls_deinit
682
deinit.argtypes = [session_t]
683
deinit.restype = None
685
handshake = _library.gnutls_handshake
686
handshake.argtypes = [session_t]
687
handshake.restype = _error_code
688
handshake.errcheck = _retry_on_error
690
transport_set_ptr = _library.gnutls_transport_set_ptr
691
transport_set_ptr.argtypes = [session_t, transport_ptr_t]
692
transport_set_ptr.restype = None
694
bye = _library.gnutls_bye
695
bye.argtypes = [session_t, close_request_t]
696
bye.restype = _error_code
697
bye.errcheck = _retry_on_error
699
check_version = _library.gnutls_check_version
700
check_version.argtypes = [ctypes.c_char_p]
701
check_version.restype = ctypes.c_char_p
703
# All the function declarations below are from gnutls/openpgp.h
705
openpgp_crt_init = _library.gnutls_openpgp_crt_init
706
openpgp_crt_init.argtypes = [ctypes.POINTER(openpgp_crt_t)]
707
openpgp_crt_init.restype = _error_code
709
openpgp_crt_import = _library.gnutls_openpgp_crt_import
710
openpgp_crt_import.argtypes = [openpgp_crt_t,
711
ctypes.POINTER(datum_t),
713
openpgp_crt_import.restype = _error_code
715
openpgp_crt_verify_self = _library.gnutls_openpgp_crt_verify_self
716
openpgp_crt_verify_self.argtypes = [openpgp_crt_t, ctypes.c_uint,
717
ctypes.POINTER(ctypes.c_uint)]
718
openpgp_crt_verify_self.restype = _error_code
720
openpgp_crt_deinit = _library.gnutls_openpgp_crt_deinit
721
openpgp_crt_deinit.argtypes = [openpgp_crt_t]
722
openpgp_crt_deinit.restype = None
724
openpgp_crt_get_fingerprint = (
725
_library.gnutls_openpgp_crt_get_fingerprint)
726
openpgp_crt_get_fingerprint.argtypes = [openpgp_crt_t,
730
openpgp_crt_get_fingerprint.restype = _error_code
732
# Remove non-public functions
733
del _error_code, _retry_on_error
734
# Create the global "gnutls" object, simulating a module
438
737
def call_pipe(connection, # : multiprocessing.Connection
439
738
func, *args, **kwargs):
440
739
"""This function is meant to be called by multiprocessing.Process
2044
2310
def fingerprint(openpgp):
2045
2311
"Convert an OpenPGP bytestring to a hexdigit fingerprint"
2046
2312
# New GnuTLS "datum" with the OpenPGP public key
2047
datum = gnutls.library.types.gnutls_datum_t(
2313
datum = gnutls.datum_t(
2048
2314
ctypes.cast(ctypes.c_char_p(openpgp),
2049
2315
ctypes.POINTER(ctypes.c_ubyte)),
2050
2316
ctypes.c_uint(len(openpgp)))
2051
2317
# New empty GnuTLS certificate
2052
crt = gnutls.library.types.gnutls_openpgp_crt_t()
2053
gnutls.library.functions.gnutls_openpgp_crt_init(
2318
crt = gnutls.openpgp_crt_t()
2319
gnutls.openpgp_crt_init(ctypes.byref(crt))
2055
2320
# Import the OpenPGP public key into the certificate
2056
gnutls.library.functions.gnutls_openpgp_crt_import(
2057
crt, ctypes.byref(datum),
2058
gnutls.library.constants.GNUTLS_OPENPGP_FMT_RAW)
2321
gnutls.openpgp_crt_import(crt, ctypes.byref(datum),
2322
gnutls.OPENPGP_FMT_RAW)
2059
2323
# Verify the self signature in the key
2060
2324
crtverify = ctypes.c_uint()
2061
gnutls.library.functions.gnutls_openpgp_crt_verify_self(
2062
crt, 0, ctypes.byref(crtverify))
2325
gnutls.openpgp_crt_verify_self(crt, 0,
2326
ctypes.byref(crtverify))
2063
2327
if crtverify.value != 0:
2064
gnutls.library.functions.gnutls_openpgp_crt_deinit(crt)
2065
raise gnutls.errors.CertificateSecurityError(
2328
gnutls.openpgp_crt_deinit(crt)
2329
raise gnutls.CertificateSecurityError("Verify failed")
2067
2330
# New buffer for the fingerprint
2068
2331
buf = ctypes.create_string_buffer(20)
2069
2332
buf_len = ctypes.c_size_t()
2070
2333
# Get the fingerprint from the certificate into the buffer
2071
gnutls.library.functions.gnutls_openpgp_crt_get_fingerprint(
2072
crt, ctypes.byref(buf), ctypes.byref(buf_len))
2334
gnutls.openpgp_crt_get_fingerprint(crt, ctypes.byref(buf),
2335
ctypes.byref(buf_len))
2073
2336
# Deinit the certificate
2074
gnutls.library.functions.gnutls_openpgp_crt_deinit(crt)
2337
gnutls.openpgp_crt_deinit(crt)
2075
2338
# Convert the buffer to a Python bytestring
2076
2339
fpr = ctypes.string_at(buf, buf_len.value)
2077
2340
# Convert the bytestring to hexadecimal notation