434
429
.format(self.name)))
432
# Pretend that we have a GnuTLS module
433
class GnuTLS(object):
434
"""This isn't so much a class as it is a module-like namespace.
435
It is instantiated once, and simulates having a GnuTLS module."""
437
_library = ctypes.cdll.LoadLibrary(
438
ctypes.util.find_library("gnutls"))
439
_need_version = "3.3.0"
441
# Need to use class name "GnuTLS" here, since this method is
442
# called before the assignment to the "gnutls" global variable
444
if GnuTLS.check_version(self._need_version) is None:
445
raise GnuTLS.Error("Needs GnuTLS {} or later"
446
.format(self._need_version))
448
# Unless otherwise indicated, the constants and types below are
449
# all from the gnutls/gnutls.h C header file.
459
E_NO_CERTIFICATE_FOUND = -49
460
OPENPGP_FMT_RAW = 0 # gnutls/openpgp.h
463
class session_int(ctypes.Structure):
465
session_t = ctypes.POINTER(session_int)
466
class certificate_credentials_st(ctypes.Structure):
468
certificate_credentials_t = ctypes.POINTER(
469
certificate_credentials_st)
470
certificate_type_t = ctypes.c_int
471
class datum_t(ctypes.Structure):
472
_fields_ = [('data', ctypes.POINTER(ctypes.c_ubyte)),
473
('size', ctypes.c_uint)]
474
class openpgp_crt_int(ctypes.Structure):
476
openpgp_crt_t = ctypes.POINTER(openpgp_crt_int)
477
openpgp_crt_fmt_t = ctypes.c_int # gnutls/openpgp.h
478
log_func = ctypes.CFUNCTYPE(None, ctypes.c_int, ctypes.c_char_p)
479
credentials_type_t = ctypes.c_int #
480
transport_ptr_t = ctypes.c_void_p
481
close_request_t = ctypes.c_int
484
class Error(Exception):
485
# We need to use the class name "GnuTLS" here, since this
486
# exception might be raised from within GnuTLS.__init__,
487
# which is called before the assignment to the "gnutls"
488
# global variable has happened.
489
def __init__(self, message = None, code = None, args=()):
490
# Default usage is by a message string, but if a return
491
# code is passed, convert it to a string with
494
if message is None and code is not None:
495
message = GnuTLS.strerror(code)
496
return super(GnuTLS.Error, self).__init__(
499
class CertificateSecurityError(Error):
503
class Credentials(object):
505
self._c_object = gnutls.certificate_credentials_t()
506
gnutls.certificate_allocate_credentials(
507
ctypes.byref(self._c_object))
508
self.type = gnutls.CRD_CERTIFICATE
511
gnutls.certificate_free_credentials(self._c_object)
513
class ClientSession(object):
514
def __init__(self, socket, credentials = None):
515
self._c_object = gnutls.session_t()
516
gnutls.init(ctypes.byref(self._c_object), gnutls.CLIENT)
517
gnutls.set_default_priority(self._c_object)
518
gnutls.transport_set_ptr(self._c_object, socket.fileno())
519
gnutls.handshake_set_private_extensions(self._c_object,
522
if credentials is None:
523
credentials = gnutls.Credentials()
524
gnutls.credentials_set(self._c_object, credentials.type,
525
ctypes.cast(credentials._c_object,
527
self.credentials = credentials
530
gnutls.deinit(self._c_object)
533
return gnutls.handshake(self._c_object)
535
def send(self, data):
539
data_len -= gnutls.record_send(self._c_object,
544
return gnutls.bye(self._c_object, gnutls.SHUT_RDWR)
546
# Error handling functions
547
def _error_code(result):
548
"""A function to raise exceptions on errors, suitable
549
for the 'restype' attribute on ctypes functions"""
552
if result == gnutls.E_NO_CERTIFICATE_FOUND:
553
raise gnutls.CertificateSecurityError(code = result)
554
raise gnutls.Error(code = result)
556
def _retry_on_error(result, func, arguments):
557
"""A function to retry on some errors, suitable
558
for the 'errcheck' attribute on ctypes functions"""
560
if result not in (gnutls.E_INTERRUPTED, gnutls.E_AGAIN):
561
return _error_code(result)
562
result = func(*arguments)
565
# Unless otherwise indicated, the function declarations below are
566
# all from the gnutls/gnutls.h C header file.
569
priority_set_direct = _library.gnutls_priority_set_direct
570
priority_set_direct.argtypes = [session_t, ctypes.c_char_p,
571
ctypes.POINTER(ctypes.c_char_p)]
572
priority_set_direct.restype = _error_code
574
init = _library.gnutls_init
575
init.argtypes = [ctypes.POINTER(session_t), ctypes.c_int]
576
init.restype = _error_code
578
set_default_priority = _library.gnutls_set_default_priority
579
set_default_priority.argtypes = [session_t]
580
set_default_priority.restype = _error_code
582
record_send = _library.gnutls_record_send
583
record_send.argtypes = [session_t, ctypes.c_void_p,
585
record_send.restype = ctypes.c_ssize_t
586
record_send.errcheck = _retry_on_error
588
certificate_allocate_credentials = (
589
_library.gnutls_certificate_allocate_credentials)
590
certificate_allocate_credentials.argtypes = [
591
ctypes.POINTER(certificate_credentials_t)]
592
certificate_allocate_credentials.restype = _error_code
594
certificate_free_credentials = (
595
_library.gnutls_certificate_free_credentials)
596
certificate_free_credentials.argtypes = [certificate_credentials_t]
597
certificate_free_credentials.restype = None
599
handshake_set_private_extensions = (
600
_library.gnutls_handshake_set_private_extensions)
601
handshake_set_private_extensions.argtypes = [session_t,
603
handshake_set_private_extensions.restype = None
605
credentials_set = _library.gnutls_credentials_set
606
credentials_set.argtypes = [session_t, credentials_type_t,
608
credentials_set.restype = _error_code
610
strerror = _library.gnutls_strerror
611
strerror.argtypes = [ctypes.c_int]
612
strerror.restype = ctypes.c_char_p
614
certificate_type_get = _library.gnutls_certificate_type_get
615
certificate_type_get.argtypes = [session_t]
616
certificate_type_get.restype = _error_code
618
certificate_get_peers = _library.gnutls_certificate_get_peers
619
certificate_get_peers.argtypes = [session_t,
620
ctypes.POINTER(ctypes.c_uint)]
621
certificate_get_peers.restype = ctypes.POINTER(datum_t)
623
global_set_log_level = _library.gnutls_global_set_log_level
624
global_set_log_level.argtypes = [ctypes.c_int]
625
global_set_log_level.restype = None
627
global_set_log_function = _library.gnutls_global_set_log_function
628
global_set_log_function.argtypes = [log_func]
629
global_set_log_function.restype = None
631
deinit = _library.gnutls_deinit
632
deinit.argtypes = [session_t]
633
deinit.restype = None
635
handshake = _library.gnutls_handshake
636
handshake.argtypes = [session_t]
637
handshake.restype = _error_code
638
handshake.errcheck = _retry_on_error
640
transport_set_ptr = _library.gnutls_transport_set_ptr
641
transport_set_ptr.argtypes = [session_t, transport_ptr_t]
642
transport_set_ptr.restype = None
644
bye = _library.gnutls_bye
645
bye.argtypes = [session_t, close_request_t]
646
bye.restype = _error_code
647
bye.errcheck = _retry_on_error
649
check_version = _library.gnutls_check_version
650
check_version.argtypes = [ctypes.c_char_p]
651
check_version.restype = ctypes.c_char_p
653
# All the function declarations below are from gnutls/openpgp.h
655
openpgp_crt_init = _library.gnutls_openpgp_crt_init
656
openpgp_crt_init.argtypes = [ctypes.POINTER(openpgp_crt_t)]
657
openpgp_crt_init.restype = _error_code
659
openpgp_crt_import = _library.gnutls_openpgp_crt_import
660
openpgp_crt_import.argtypes = [openpgp_crt_t,
661
ctypes.POINTER(datum_t),
663
openpgp_crt_import.restype = _error_code
665
openpgp_crt_verify_self = _library.gnutls_openpgp_crt_verify_self
666
openpgp_crt_verify_self.argtypes = [openpgp_crt_t, ctypes.c_uint,
667
ctypes.POINTER(ctypes.c_uint)]
668
openpgp_crt_verify_self.restype = _error_code
670
openpgp_crt_deinit = _library.gnutls_openpgp_crt_deinit
671
openpgp_crt_deinit.argtypes = [openpgp_crt_t]
672
openpgp_crt_deinit.restype = None
674
openpgp_crt_get_fingerprint = (
675
_library.gnutls_openpgp_crt_get_fingerprint)
676
openpgp_crt_get_fingerprint.argtypes = [openpgp_crt_t,
680
openpgp_crt_get_fingerprint.restype = _error_code
682
# Remove non-public functions
683
del _error_code, _retry_on_error
684
# Create the global "gnutls" object, simulating a module
437
687
def call_pipe(connection, # : multiprocessing.Connection
438
688
func, *args, **kwargs):
439
689
"""This function is meant to be called by multiprocessing.Process
2043
2277
def fingerprint(openpgp):
2044
2278
"Convert an OpenPGP bytestring to a hexdigit fingerprint"
2045
2279
# New GnuTLS "datum" with the OpenPGP public key
2046
datum = gnutls.library.types.gnutls_datum_t(
2280
datum = gnutls.datum_t(
2047
2281
ctypes.cast(ctypes.c_char_p(openpgp),
2048
2282
ctypes.POINTER(ctypes.c_ubyte)),
2049
2283
ctypes.c_uint(len(openpgp)))
2050
2284
# New empty GnuTLS certificate
2051
crt = gnutls.library.types.gnutls_openpgp_crt_t()
2052
gnutls.library.functions.gnutls_openpgp_crt_init(
2285
crt = gnutls.openpgp_crt_t()
2286
gnutls.openpgp_crt_init(ctypes.byref(crt))
2054
2287
# Import the OpenPGP public key into the certificate
2055
gnutls.library.functions.gnutls_openpgp_crt_import(
2056
crt, ctypes.byref(datum),
2057
gnutls.library.constants.GNUTLS_OPENPGP_FMT_RAW)
2288
gnutls.openpgp_crt_import(crt, ctypes.byref(datum),
2289
gnutls.OPENPGP_FMT_RAW)
2058
2290
# Verify the self signature in the key
2059
2291
crtverify = ctypes.c_uint()
2060
gnutls.library.functions.gnutls_openpgp_crt_verify_self(
2061
crt, 0, ctypes.byref(crtverify))
2292
gnutls.openpgp_crt_verify_self(crt, 0,
2293
ctypes.byref(crtverify))
2062
2294
if crtverify.value != 0:
2063
gnutls.library.functions.gnutls_openpgp_crt_deinit(crt)
2064
raise gnutls.errors.CertificateSecurityError(
2295
gnutls.openpgp_crt_deinit(crt)
2296
raise gnutls.CertificateSecurityError("Verify failed")
2066
2297
# New buffer for the fingerprint
2067
2298
buf = ctypes.create_string_buffer(20)
2068
2299
buf_len = ctypes.c_size_t()
2069
2300
# Get the fingerprint from the certificate into the buffer
2070
gnutls.library.functions.gnutls_openpgp_crt_get_fingerprint(
2071
crt, ctypes.byref(buf), ctypes.byref(buf_len))
2301
gnutls.openpgp_crt_get_fingerprint(crt, ctypes.byref(buf),
2302
ctypes.byref(buf_len))
2072
2303
# Deinit the certificate
2073
gnutls.library.functions.gnutls_openpgp_crt_deinit(crt)
2304
gnutls.openpgp_crt_deinit(crt)
2074
2305
# Convert the buffer to a Python bytestring
2075
2306
fpr = ctypes.string_at(buf, buf_len.value)
2076
2307
# Convert the bytestring to hexadecimal notation