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  • Committer: Teddy Hogeborn
  • Date: 2021-03-21 19:51:15 UTC
  • Revision ID: teddy@recompile.se-20210321195115-qe6g0fyj1kabwlav
Fix theoretical GnuTLS bug

Fix "NameError: global name '_error_code' is not defined" error if
GNUTLS_E_INTERRUPTED or GNUTLS_E_AGAIN was ever returned from
gnutls_record_send().

* mandos (gnutls._retry_on_error): Import "_error_code" from outer
  class scope to local function scope via a keyword argument.

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Lines of Context:
mandos
563
563
    OPENPGP_FMT_RAW = 0         # gnutls/openpgp.h
564
564
 
565
565
    # Types
566
 
    class _session_int(ctypes.Structure):
 
566
    class session_int(ctypes.Structure):
567
567
        _fields_ = []
568
 
    session_t = ctypes.POINTER(_session_int)
 
568
    session_t = ctypes.POINTER(session_int)
569
569
 
570
570
    class certificate_credentials_st(ctypes.Structure):
571
571
        _fields_ = []
577
577
        _fields_ = [('data', ctypes.POINTER(ctypes.c_ubyte)),
578
578
                    ('size', ctypes.c_uint)]
579
579
 
580
 
    class _openpgp_crt_int(ctypes.Structure):
 
580
    class openpgp_crt_int(ctypes.Structure):
581
581
        _fields_ = []
582
 
    openpgp_crt_t = ctypes.POINTER(_openpgp_crt_int)
 
582
    openpgp_crt_t = ctypes.POINTER(openpgp_crt_int)
583
583
    openpgp_crt_fmt_t = ctypes.c_int  # gnutls/openpgp.h
584
584
    log_func = ctypes.CFUNCTYPE(None, ctypes.c_int, ctypes.c_char_p)
585
585
    credentials_type_t = ctypes.c_int
594
594
            # gnutls.strerror()
595
595
            self.code = code
596
596
            if message is None and code is not None:
597
 
                message = gnutls.strerror(code).decode(
598
 
                    "utf-8", errors="replace")
 
597
                message = gnutls.strerror(code)
599
598
            return super(gnutls.Error, self).__init__(
600
599
                message, *args)
601
600
 
602
601
    class CertificateSecurityError(Error):
603
602
        pass
604
603
 
605
 
    class PointerTo:
606
 
        def __init__(self, cls):
607
 
            self.cls = cls
608
 
 
609
 
        def from_param(self, obj):
610
 
            if not isinstance(obj, self.cls):
611
 
                raise TypeError("Not of type {}: {!r}"
612
 
                                .format(self.cls.__name__, obj))
613
 
            return ctypes.byref(obj.from_param(obj))
614
 
 
615
 
    class CastToVoidPointer:
616
 
        def __init__(self, cls):
617
 
            self.cls = cls
618
 
 
619
 
        def from_param(self, obj):
620
 
            if not isinstance(obj, self.cls):
621
 
                raise TypeError("Not of type {}: {!r}"
622
 
                                .format(self.cls.__name__, obj))
623
 
            return ctypes.cast(obj.from_param(obj), ctypes.c_void_p)
624
 
 
625
 
    class With_from_param:
626
 
        @classmethod
627
 
        def from_param(cls, obj):
628
 
            return obj._as_parameter_
629
 
 
630
604
    # Classes
631
 
    class Credentials(With_from_param):
 
605
    class Credentials:
632
606
        def __init__(self):
633
 
            self._as_parameter_ = gnutls.certificate_credentials_t()
634
 
            gnutls.certificate_allocate_credentials(self)
 
607
            self._c_object = gnutls.certificate_credentials_t()
 
608
            gnutls.certificate_allocate_credentials(
 
609
                ctypes.byref(self._c_object))
635
610
            self.type = gnutls.CRD_CERTIFICATE
636
611
 
637
612
        def __del__(self):
638
 
            gnutls.certificate_free_credentials(self)
 
613
            gnutls.certificate_free_credentials(self._c_object)
639
614
 
640
 
    class ClientSession(With_from_param):
 
615
    class ClientSession:
641
616
        def __init__(self, socket, credentials=None):
642
 
            self._as_parameter_ = gnutls.session_t()
 
617
            self._c_object = gnutls.session_t()
643
618
            gnutls_flags = gnutls.CLIENT
644
619
            if gnutls.check_version(b"3.5.6"):
645
620
                gnutls_flags |= gnutls.NO_TICKETS
646
621
            if gnutls.has_rawpk:
647
622
                gnutls_flags |= gnutls.ENABLE_RAWPK
648
 
            gnutls.init(self, gnutls_flags)
 
623
            gnutls.init(ctypes.byref(self._c_object), gnutls_flags)
649
624
            del gnutls_flags
650
 
            gnutls.set_default_priority(self)
651
 
            gnutls.transport_set_ptr(self, socket.fileno())
652
 
            gnutls.handshake_set_private_extensions(self, True)
 
625
            gnutls.set_default_priority(self._c_object)
 
626
            gnutls.transport_set_ptr(self._c_object, socket.fileno())
 
627
            gnutls.handshake_set_private_extensions(self._c_object,
 
628
                                                    True)
653
629
            self.socket = socket
654
630
            if credentials is None:
655
631
                credentials = gnutls.Credentials()
656
 
            gnutls.credentials_set(self, credentials.type,
657
 
                                   credentials)
 
632
            gnutls.credentials_set(self._c_object, credentials.type,
 
633
                                   ctypes.cast(credentials._c_object,
 
634
                                               ctypes.c_void_p))
658
635
            self.credentials = credentials
659
636
 
660
637
        def __del__(self):
661
 
            gnutls.deinit(self)
 
638
            gnutls.deinit(self._c_object)
662
639
 
663
640
        def handshake(self):
664
 
            return gnutls.handshake(self)
 
641
            return gnutls.handshake(self._c_object)
665
642
 
666
643
        def send(self, data):
667
644
            data = bytes(data)
668
645
            data_len = len(data)
669
646
            while data_len > 0:
670
 
                data_len -= gnutls.record_send(self, data[-data_len:],
 
647
                data_len -= gnutls.record_send(self._c_object,
 
648
                                               data[-data_len:],
671
649
                                               data_len)
672
650
 
673
651
        def bye(self):
674
 
            return gnutls.bye(self, gnutls.SHUT_RDWR)
 
652
            return gnutls.bye(self._c_object, gnutls.SHUT_RDWR)
675
653
 
676
654
    # Error handling functions
677
655
    def _error_code(result):
678
656
        """A function to raise exceptions on errors, suitable
679
657
        for the 'restype' attribute on ctypes functions"""
680
 
        if result >= gnutls.E_SUCCESS:
 
658
        if result >= 0:
681
659
            return result
682
660
        if result == gnutls.E_NO_CERTIFICATE_FOUND:
683
661
            raise gnutls.CertificateSecurityError(code=result)
687
665
                        _error_code=_error_code):
688
666
        """A function to retry on some errors, suitable
689
667
        for the 'errcheck' attribute on ctypes functions"""
690
 
        while result < gnutls.E_SUCCESS:
 
668
        while result < 0:
691
669
            if result not in (gnutls.E_INTERRUPTED, gnutls.E_AGAIN):
692
670
                return _error_code(result)
693
671
            result = func(*arguments)
698
676
 
699
677
    # Functions
700
678
    priority_set_direct = _library.gnutls_priority_set_direct
701
 
    priority_set_direct.argtypes = [ClientSession, ctypes.c_char_p,
 
679
    priority_set_direct.argtypes = [session_t, ctypes.c_char_p,
702
680
                                    ctypes.POINTER(ctypes.c_char_p)]
703
681
    priority_set_direct.restype = _error_code
704
682
 
705
683
    init = _library.gnutls_init
706
 
    init.argtypes = [PointerTo(ClientSession), ctypes.c_int]
 
684
    init.argtypes = [ctypes.POINTER(session_t), ctypes.c_int]
707
685
    init.restype = _error_code
708
686
 
709
687
    set_default_priority = _library.gnutls_set_default_priority
710
 
    set_default_priority.argtypes = [ClientSession]
 
688
    set_default_priority.argtypes = [session_t]
711
689
    set_default_priority.restype = _error_code
712
690
 
713
691
    record_send = _library.gnutls_record_send
714
 
    record_send.argtypes = [ClientSession, ctypes.c_void_p,
 
692
    record_send.argtypes = [session_t, ctypes.c_void_p,
715
693
                            ctypes.c_size_t]
716
694
    record_send.restype = ctypes.c_ssize_t
717
695
    record_send.errcheck = _retry_on_error
719
697
    certificate_allocate_credentials = (
720
698
        _library.gnutls_certificate_allocate_credentials)
721
699
    certificate_allocate_credentials.argtypes = [
722
 
        PointerTo(Credentials)]
 
700
        ctypes.POINTER(certificate_credentials_t)]
723
701
    certificate_allocate_credentials.restype = _error_code
724
702
 
725
703
    certificate_free_credentials = (
726
704
        _library.gnutls_certificate_free_credentials)
727
 
    certificate_free_credentials.argtypes = [Credentials]
 
705
    certificate_free_credentials.argtypes = [
 
706
        certificate_credentials_t]
728
707
    certificate_free_credentials.restype = None
729
708
 
730
709
    handshake_set_private_extensions = (
731
710
        _library.gnutls_handshake_set_private_extensions)
732
 
    handshake_set_private_extensions.argtypes = [ClientSession,
 
711
    handshake_set_private_extensions.argtypes = [session_t,
733
712
                                                 ctypes.c_int]
734
713
    handshake_set_private_extensions.restype = None
735
714
 
736
715
    credentials_set = _library.gnutls_credentials_set
737
 
    credentials_set.argtypes = [ClientSession, credentials_type_t,
738
 
                                CastToVoidPointer(Credentials)]
 
716
    credentials_set.argtypes = [session_t, credentials_type_t,
 
717
                                ctypes.c_void_p]
739
718
    credentials_set.restype = _error_code
740
719
 
741
720
    strerror = _library.gnutls_strerror
743
722
    strerror.restype = ctypes.c_char_p
744
723
 
745
724
    certificate_type_get = _library.gnutls_certificate_type_get
746
 
    certificate_type_get.argtypes = [ClientSession]
 
725
    certificate_type_get.argtypes = [session_t]
747
726
    certificate_type_get.restype = _error_code
748
727
 
749
728
    certificate_get_peers = _library.gnutls_certificate_get_peers
750
 
    certificate_get_peers.argtypes = [ClientSession,
 
729
    certificate_get_peers.argtypes = [session_t,
751
730
                                      ctypes.POINTER(ctypes.c_uint)]
752
731
    certificate_get_peers.restype = ctypes.POINTER(datum_t)
753
732
 
760
739
    global_set_log_function.restype = None
761
740
 
762
741
    deinit = _library.gnutls_deinit
763
 
    deinit.argtypes = [ClientSession]
 
742
    deinit.argtypes = [session_t]
764
743
    deinit.restype = None
765
744
 
766
745
    handshake = _library.gnutls_handshake
767
 
    handshake.argtypes = [ClientSession]
768
 
    handshake.restype = ctypes.c_int
 
746
    handshake.argtypes = [session_t]
 
747
    handshake.restype = _error_code
769
748
    handshake.errcheck = _retry_on_error
770
749
 
771
750
    transport_set_ptr = _library.gnutls_transport_set_ptr
772
 
    transport_set_ptr.argtypes = [ClientSession, transport_ptr_t]
 
751
    transport_set_ptr.argtypes = [session_t, transport_ptr_t]
773
752
    transport_set_ptr.restype = None
774
753
 
775
754
    bye = _library.gnutls_bye
776
 
    bye.argtypes = [ClientSession, close_request_t]
777
 
    bye.restype = ctypes.c_int
 
755
    bye.argtypes = [session_t, close_request_t]
 
756
    bye.restype = _error_code
778
757
    bye.errcheck = _retry_on_error
779
758
 
780
759
    check_version = _library.gnutls_check_version
854
833
 
855
834
    if check_version(b"3.6.4"):
856
835
        certificate_type_get2 = _library.gnutls_certificate_type_get2
857
 
        certificate_type_get2.argtypes = [ClientSession, ctypes.c_int]
 
836
        certificate_type_get2.argtypes = [session_t, ctypes.c_int]
858
837
        certificate_type_get2.restype = _error_code
859
838
 
860
839
    # Remove non-public functions
2320
2299
            priority = self.server.gnutls_priority
2321
2300
            if priority is None:
2322
2301
                priority = "NORMAL"
2323
 
            gnutls.priority_set_direct(session,
2324
 
                                       priority.encode("utf-8"), None)
 
2302
            gnutls.priority_set_direct(session._c_object,
 
2303
                                       priority.encode("utf-8"),
 
2304
                                       None)
2325
2305
 
2326
2306
            # Start communication using the Mandos protocol
2327
2307
            # Get protocol number
2354
2334
                    except (TypeError, gnutls.Error) as error:
2355
2335
                        logger.warning("Bad certificate: %s", error)
2356
2336
                        return
2357
 
                    logger.debug("Key ID: %s",
2358
 
                                 key_id.decode("utf-8",
2359
 
                                               errors="replace"))
 
2337
                    logger.debug("Key ID: %s", key_id)
2360
2338
 
2361
2339
                else:
2362
2340
                    key_id = b""
2454
2432
    def peer_certificate(session):
2455
2433
        "Return the peer's certificate as a bytestring"
2456
2434
        try:
2457
 
            cert_type = gnutls.certificate_type_get2(
2458
 
                session, gnutls.CTYPE_PEERS)
 
2435
            cert_type = gnutls.certificate_type_get2(session._c_object,
 
2436
                                                     gnutls.CTYPE_PEERS)
2459
2437
        except AttributeError:
2460
 
            cert_type = gnutls.certificate_type_get(session)
 
2438
            cert_type = gnutls.certificate_type_get(session._c_object)
2461
2439
        if gnutls.has_rawpk:
2462
2440
            valid_cert_types = frozenset((gnutls.CRT_RAWPK,))
2463
2441
        else:
2470
2448
            return b""
2471
2449
        list_size = ctypes.c_uint(1)
2472
2450
        cert_list = (gnutls.certificate_get_peers
2473
 
                     (session, ctypes.byref(list_size)))
 
2451
                     (session._c_object, ctypes.byref(list_size)))
2474
2452
        if not bool(cert_list) and list_size.value != 0:
2475
2453
            raise gnutls.Error("error getting peer certificate")
2476
2454
        if list_size.value == 0:
3201
3179
 
3202
3180
        @gnutls.log_func
3203
3181
        def debug_gnutls(level, string):
3204
 
            logger.debug("GnuTLS: %s",
3205
 
                         string[:-1].decode("utf-8",
3206
 
                                            errors="replace"))
 
3182
            logger.debug("GnuTLS: %s", string[:-1])
3207
3183
 
3208
3184
        gnutls.global_set_log_function(debug_gnutls)
3209
3185