kex_gss.py 文件源码

def _parse_kexgss_groupreq(self, m):
        """
        Parse the SSH2_MSG_KEXGSS_GROUPREQ message (server mode).

        :param `.Message` m: The content of the
            SSH2_MSG_KEXGSS_GROUPREQ message
        """
        minbits = m.get_int()
        preferredbits = m.get_int()
        maxbits = m.get_int()
        # smoosh the user's preferred size into our own limits
        if preferredbits > self.max_bits:
            preferredbits = self.max_bits
        if preferredbits < self.min_bits:
            preferredbits = self.min_bits
        # fix min/max if they're inconsistent.  technically, we could just pout
        # and hang up, but there's no harm in giving them the benefit of the
        # doubt and just picking a bitsize for them.
        if minbits > preferredbits:
            minbits = preferredbits
        if maxbits < preferredbits:
            maxbits = preferredbits
        # now save a copy
        self.min_bits = minbits
        self.preferred_bits = preferredbits
        self.max_bits = maxbits
        # generate prime
        pack = self.transport._get_modulus_pack()
        if pack is None:
            raise SSHException(
                'Can\'t do server-side gex with no modulus pack')
        self.transport._log(
            DEBUG,  # noqa
            'Picking p (%d <= %d <= %d bits)' % (
                minbits, preferredbits, maxbits))
        self.g, self.p = pack.get_modulus(minbits, preferredbits, maxbits)
        m = Message()
        m.add_byte(c_MSG_KEXGSS_GROUP)
        m.add_mpint(self.p)
        m.add_mpint(self.g)
        self.transport._send_message(m)
        self.transport._expect_packet(MSG_KEXGSS_INIT)