kmsRequestV4.py

import binascii
import time
import logging

from kmsBase import kmsBase
from structure import Structure
from aes import AES
from formatText import shell_message, justify, byterize

# v4 AES Key
key = bytearray(
    [0x05, 0x3D, 0x83, 0x07, 0xF9, 0xE5, 0xF0, 0x88, 0xEB, 0x5E, 0xA6, 0x68, 0x6C, 0xF0, 0x37, 0xC7, 0xE4, 0xEF, 0xD2,
     0xD6])


# Xor Buffer
def xorBuffer(source, offset, destination, size):
    for i in range(0, size):
        destination[i] ^= source[i + offset]


class kmsRequestV4(kmsBase):
    class RequestV4(Structure):
        commonHdr = ()
        structure = (
            ('bodyLength1', '<I'),
            ('bodyLength2', '<I'),
            ('request', ':', kmsBase.kmsRequestStruct),
            ('hash', '16s'),
            ('padding', ':'),
        )

    class ResponseV4(Structure):
        commonHdr = ()
        structure = (
            ('bodyLength1', '<I=len(response) + len(hash)'),
            ('unknown', '!I=0x00000200'),
            ('bodyLength2', '<I=len(response) + len(hash)'),
            ('response', ':', kmsBase.kmsResponseStruct),
            ('hash', '16s'),
            ('padding', ':'),
        )

    def executeRequestLogic(self):
        requestData = self.RequestV4(self.data)

        response = self.serverLogic(requestData['request'])

        thehash = self.generateHash(bytearray(str(response).encode('latin-1')))  # *2to3*

        self.responseData = self.generateResponse(response, thehash)

        time.sleep(1)  # request sent back too quick for Windows 2008 R2, slow it down.

    def generateHash(self, message):
        """
        The KMS v4 hash is a variant of CMAC-AES-128. There are two key differences:
        * The 'AES' used is modified in particular ways:
          * The basic algorithm is Rjindael with a conceptual 160bit key and 128bit blocks.
            This isn't part of the AES standard, but it works the way you'd expect.
            Accordingly, the algorithm uses 11 rounds and a 192 byte expanded key.
        * The trailing block is not XORed with a generated subkey, as defined in CMAC.
          This is probably because the subkey generation algorithm is only defined for
          situations where block and key size are the same.
        """
        aes = AES()

        messageSize = len(message)
        lastBlock = bytearray(16)
        hashBuffer = bytearray(16)

        # MessageSize / Blocksize.
        j = messageSize >> 4

        # Remainding bytes.
        k = messageSize & 0xf

        # Hash.
        for i in range(0, j):
            xorBuffer(message, i << 4, hashBuffer, 16)
            hashBuffer = bytearray(aes.encrypt(hashBuffer, key, len(key)))

        # Bit Padding.
        ii = 0
        for i in range(j << 4, k + (j << 4)):
            lastBlock[ii] = message[i]
            ii += 1
        lastBlock[k] = 0x80

        xorBuffer(lastBlock, 0, hashBuffer, 16)
        hashBuffer = bytearray(aes.encrypt(hashBuffer, key, len(key)))

        return hashBuffer  # *2to3*

    def generateResponse(self, responseBuffer, thehash):
        bodyLength = len(responseBuffer) + len(thehash)
        response = self.ResponseV4()
        response['response'] = responseBuffer
        response['hash'] = thehash.decode('latin-1')  # *2to3*
        response['padding'] = self.getResponsePadding(bodyLength).decode('latin-1')  # *2to3*

        ## Debug stuff.
        shell_message(nshell=16)
        response = byterize(response)
        logging.debug("KMS V4 Response: \n%s\n" % justify(response.dump(print_to_stdout=False)))
        logging.debug("KMS V4 Response Bytes: \n%s\n" % justify(
            binascii.b2a_hex(str(response).encode('latin-1')).decode('utf-8')))  # *2to3*

        return str(response)

    def getResponse(self):
        return self.responseData

    def generateRequest(self, requestBase):
        thehash = self.generateHash(bytearray(str(requestBase).encode('latin-1')))  # *2to3*

        bodyLength = len(requestBase) + len(thehash)

        request = kmsRequestV4.RequestV4()
        request['bodyLength1'] = bodyLength
        request['bodyLength2'] = bodyLength
        request['request'] = requestBase
        request['hash'] = thehash.decode('latin-1')  # *2to3*
        request['padding'] = self.getResponsePadding(bodyLength).decode('latin-1')  # *2to3*

        ## Debug stuff.
        shell_message(nshell=10)
        request = byterize(request)
        logging.debug("Request V4 Data: \n%s\n" % justify(request.dump(print_to_stdout=False)))
        logging.debug(
            "Request V4: \n%s\n" % justify(binascii.b2a_hex(str(request).encode('latin-1')).decode('utf-8')))  # *2to3*

        return request