M2Crypto.AuthCookie — M2Crypto documentation

# Source code for M2Crypto.AuthCookie

    from __future__ import absolute_import

    """Secure Authenticator Cookies

    Copyright (c) 1999-2002 Ng Pheng Siong. All rights reserved."""

    import logging
    import re
    import time

    from M2Crypto import Rand, m2, six, util
    from M2Crypto.six.moves.http_cookies import SimpleCookie

    from typing import re as type_re, AnyStr, Optional, Union  # noqa

    _MIX_FORMAT = 'exp=%f&data=%s&digest='
    _MIX_RE = re.compile(r'exp=(\d+\.\d+)&data=(.+)&digest=(\S*)')

    log = logging.getLogger(__name__)

    def mix(expiry, data, format=_MIX_FORMAT):
        # type: (float, AnyStr, str) -> AnyStr
        return format % (expiry, data)

    def unmix(dough, regex=_MIX_RE):
        # type: (AnyStr, type_re) -> object
        mo = regex.match(dough)
        if mo:
            return float(mo.group(1)), mo.group(2)
        else:
            return None

    def unmix3(dough, regex=_MIX_RE):
        # type: (AnyStr, type_re) -> Optional[tuple[float, AnyStr, AnyStr]]
        mo = regex.match(dough)
        if mo:
            return float(mo.group(1)), mo.group(2), mo.group(3)
        else:
            return None

    _TOKEN = '_M2AUTH_'  # type: str

    class AuthCookieJar(object):

        _keylen = 20  # type: int

        def __init__(self):
            # type: () -> None
            self._key = Rand.rand_bytes(self._keylen)

        def _hmac(self, key, data):
            # type: (bytes, str) -> str
            return util.bin_to_hex(m2.hmac(key, six.ensure_binary(data), m2.sha1()))

        def makeCookie(self, expiry, data):
            # type: (float, str) -> AuthCookie
            """
            Make a cookie

            :param expiry: expiration time (float in seconds)
            :param data: cookie content
            :return: AuthCookie object
            """
            if not isinstance(expiry, (six.integer_types, float)):
                raise ValueError('Expiration time must be number, not "%s' % expiry)
            dough = mix(expiry, data)
            return AuthCookie(expiry, data, dough, self._hmac(self._key, dough))

        def isGoodCookie(self, cookie):
            # type: (AuthCookie) -> Union[bool, int]
            assert isinstance(cookie, AuthCookie)
            if cookie.isExpired():
                return 0
            c = self.makeCookie(cookie._expiry, cookie._data)
            return (c._expiry == cookie._expiry) \
                and (c._data == cookie._data) \
                and (c._mac == cookie._mac) \
                and (c.output() == cookie.output())

        def isGoodCookieString(self, cookie_str, _debug=False):
            # type: (Union[dict, bytes], bool) -> Union[bool, int]
            c = SimpleCookie()
            c.load(cookie_str)
            if _TOKEN not in c:
                log.debug('_TOKEN not in c (keys = %s)', dir(c))
                return 0
            undough = unmix3(c[_TOKEN].value)
            if undough is None:
                log.debug('undough is None')
                return 0
            exp, data, mac = undough
            c2 = self.makeCookie(exp, data)
            if _debug and (c2._mac == mac):
                log.error('cookie_str = %s', cookie_str)
                log.error('c2.isExpired = %s', c2.isExpired())
                log.error('mac = %s', mac)
                log.error('c2._mac = %s', c2._mac)
                log.error('c2._mac == mac: %s', str(c2._mac == mac))
            return (not c2.isExpired()) and (c2._mac == mac)

    class AuthCookie(object):

        def __init__(self, expiry, data, dough, mac):
            # type: (float, str, str, str) -> None
            """
            Create new authentication cookie

            :param expiry: expiration time (in seconds)
            :param data: cookie payload (as a string)
            :param dough: expiry & data concatenated to URL compliant
                          string
            :param mac: SHA1-based HMAC of dough and random key
            """
            self._expiry = expiry
            self._data = data
            self._mac = mac
            self._cookie = SimpleCookie()
            self._cookie[_TOKEN] = '%s%s' % (dough, mac)
            self._name = '%s%s' % (dough, mac)  # WebKit only.

        def expiry(self):
            # type: () -> float
            """Return the cookie's expiry time."""
            return self._expiry

        def data(self):
            # type: () -> str
            """Return the data portion of the cookie."""
            return self._data

        def mac(self):
            # type: () -> str
            """Return the cookie's MAC."""
            return self._mac

        def output(self, header="Set-Cookie:"):
            # type: (Optional[str]) -> str
            """Return the cookie's output in "Set-Cookie" format."""
            return self._cookie.output(header=header)

        def value(self):
            # type: () -> str
            """Return the cookie's output minus the "Set-Cookie: " portion.
            """
            return self._cookie[_TOKEN].value

        def isExpired(self):
            # type: () -> bool
            """Return 1 if the cookie has expired, 0 otherwise."""
            return isinstance(self._expiry, (float, six.integer_types)) and \
                (time.time() > self._expiry)

        # Following two methods are for WebKit only.
        # I may wish to push them to WKAuthCookie, but they are part
        # of the API now. Oh well.
        def name(self):
            # type: () -> str
            return self._name

        def headerValue(self):
            # type: () -> str
            return self.value()