pysim/pySim/transport/pcsc.py

# -*- coding: utf-8 -*-

# Copyright (C) 2009-2010  Sylvain Munaut <tnt@246tNt.com>
# Copyright (C) 2010-2023  Harald Welte <laforge@gnumonks.org>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#

import argparse
import re
from typing import Optional

from smartcard.CardConnection import CardConnection
from smartcard.CardRequest import CardRequest
from smartcard.Exceptions import NoCardException, CardRequestTimeoutException, CardConnectionException
from smartcard.System import readers
from smartcard.ExclusiveConnectCardConnection import ExclusiveConnectCardConnection
from smartcard.ATR import ATR

from osmocom.utils import h2i, i2h, Hexstr

from pySim.exceptions import NoCardError, ProtocolError, ReaderError
from pySim.transport import LinkBaseTpdu
from pySim.utils import ResTuple


class PcscSimLink(LinkBaseTpdu):
    """ pySim: PCSC reader transport link."""
    name = 'PC/SC'

    def __init__(self, opts: argparse.Namespace = argparse.Namespace(pcsc_dev=0), **kwargs):
        super().__init__(**kwargs)
        self._reader = None
        r = readers()
        if opts.pcsc_dev is not None:
            # actual reader index number (integer)
            reader_number = opts.pcsc_dev
            if reader_number >= len(r):
                raise ReaderError('No reader found for number %d' % reader_number)
            self._reader = r[reader_number]
        else:
            # reader regex string
            cre = re.compile(opts.pcsc_regex)
            for reader in r:
                if cre.search(reader.name):
                    self._reader = reader
                    break
            if not self._reader:
                raise ReaderError('No matching reader found for regex %s' % opts.pcsc_regex)

        self._con = self._reader.createConnection()
        if not getattr(opts, "pcsc_shared", False):
            self._con = ExclusiveConnectCardConnection(self._con)

    def __del__(self):
        try:
            # FIXME: this causes multiple warnings in Python 3.5.3
            self._con.disconnect()
        except:
            pass

    def wait_for_card(self, timeout: Optional[int] = None, newcardonly: bool = False):
        cr = CardRequest(readers=[self._reader],
                         timeout=timeout, newcardonly=newcardonly)
        try:
            cr.waitforcard()
        except CardRequestTimeoutException as exc:
            raise NoCardError() from exc
        self.connect()

    def connect(self):
        try:
            # To avoid leakage of resources, make sure the reader is disconnected
            self.disconnect()

            # Make card connection and select a suitable communication protocol
            # (Even though pyscard provides an automatic protocol selection, we will make an independent decision
            #  based on the ATR. There are two reasons for that:
            #  1) In case a card supports T=0 and T=1, we perfer to use T=0.
            #  2) The automatic protocol selection may be unreliabe on some platforms
            #     see also: https://osmocom.org/issues/6952)
            self._con.connect()
            atr = ATR(self._con.getATR())
            if atr.isT0Supported():
                self._con.setProtocol(CardConnection.T0_protocol)
                self.set_tpdu_format(0)
            elif atr.isT1Supported():
                self._con.setProtocol(CardConnection.T1_protocol)
                self.set_tpdu_format(1)
            else:
                raise ReaderError('Unsupported card protocol')
        except CardConnectionException as exc:
            raise ProtocolError() from exc
        except NoCardException as exc:
            raise NoCardError() from exc

    def get_atr(self) -> Hexstr:
        return i2h(self._con.getATR())

    def disconnect(self):
        self._con.disconnect()

    def _reset_card(self):
        self.disconnect()
        self.connect()
        return 1

    def send_tpdu(self, tpdu: Hexstr) -> ResTuple:
        data, sw1, sw2 = self._con.transmit(h2i(tpdu))
        sw = [sw1, sw2]

        # Return value
        return i2h(data), i2h(sw)

    def __str__(self) -> str:
        return "PCSC[%s]" % (self._reader)

    @staticmethod
    def argparse_add_reader_args(arg_parser: argparse.ArgumentParser):
        pcsc_group = arg_parser.add_argument_group('PC/SC Reader',
        """Use a PC/SC card reader to talk to the SIM card.  PC/SC is a standard API for how applications
access smart card readers, and is available on a variety of operating systems, such as Microsoft
Windows, MacOS X and Linux.  Most vendors of smart card readers provide drivers that offer a PC/SC
interface, if not even a generic USB CCID driver is used.  You can use a tool like ``pcsc_scan -r``
to obtain a list of readers available on your system. """)
        pcsc_group.add_argument('--pcsc-shared', action='store_true',
                                help='Open PC/SC reaer in SHARED access (default: EXCLUSIVE)')
        dev_group = pcsc_group.add_mutually_exclusive_group()
        dev_group.add_argument('-p', '--pcsc-device', type=int, dest='pcsc_dev', metavar='PCSC', default=None,
                               help='Number of PC/SC reader to use for SIM access')
        dev_group.add_argument('--pcsc-regex', type=str, dest='pcsc_regex', metavar='REGEX', default=None,
                               help='Regex matching PC/SC reader to use for SIM access')