# Author: Hubert Kario, (c) 2015-2018
# Released under Gnu GPL v2.0, see LICENSE file for details
"""Example MAC value fuzzer"""

from __future__ import print_function
import traceback
import sys
import getopt
from itertools import chain
from random import sample

from tlsfuzzer.runner import Runner
from tlsfuzzer.messages import Connect, ClientHelloGenerator, \
        ClientKeyExchangeGenerator, ChangeCipherSpecGenerator, \
        FinishedGenerator, ApplicationDataGenerator, \
        fuzz_padding, AlertGenerator
from tlsfuzzer.expect import ExpectServerHello, ExpectCertificate, \
        ExpectServerHelloDone, ExpectChangeCipherSpec, ExpectFinished, \
        ExpectAlert, ExpectClose, ExpectApplicationData

from tlslite.constants import CipherSuite, AlertLevel, AlertDescription
from tlslite.utils.compat import compatAscii2Bytes
from tlsfuzzer.utils.lists import natural_sort_keys


version = 6


def help_msg():
    print("Usage: <script-name> [-h hostname] [-p port] [[probe-name] ...]")
    print(" -h hostname    name of the host to run the test against")
    print("                localhost by default")
    print(" -p port        port number to use for connection, 4433 by default")
    print(" probe-name     if present, will run only the probes with given")
    print("                names and not all of them, e.g \"sanity\"")
    print(" -e probe-name  exclude the probe from the list of the ones run")
    print("                may be specified multiple times")
    print(" -x probe-name  expect the probe to fail. When such probe passes despite being marked like this")
    print("                it will be reported in the test summary and the whole script will fail.")
    print("                May be specified multiple times.")
    print(" -X message     expect the `message` substring in exception raised during")
    print("                execution of preceding expected failure probe")
    print("                usage: [-x probe-name] [-X exception], order is compulsory!")
    print(" -n num         run 'num' or all(if 0) tests instead of default(all)")
    print("                (excluding \"sanity\" tests)")
    print(" --help         this message")


def main():
    """check if zero-filled padding is accepted by server in SSLv3"""
    host = "localhost"
    port = 4433
    num_limit = None
    run_exclude = set()
    expected_failures = {}
    last_exp_tmp = None

    argv = sys.argv[1:]
    opts, args = getopt.getopt(argv, "h:p:e:x:X:n:", ["help"])
    for opt, arg in opts:
        if opt == '-h':
            host = arg
        elif opt == '-p':
            port = int(arg)
        elif opt == '-e':
            run_exclude.add(arg)
        elif opt == '-x':
            expected_failures[arg] = None
            last_exp_tmp = str(arg)
        elif opt == '-X':
            if not last_exp_tmp:
                raise ValueError("-x has to be specified before -X")
            expected_failures[last_exp_tmp] = str(arg)
        elif opt == '-n':
            num_limit = int(arg)
        elif opt == '--help':
            help_msg()
            sys.exit(0)
        else:
            raise ValueError("Unknown option: {0}".format(opt))

    if args:
        run_only = set(args)
    else:
        run_only = None

    conversations = {}

    # normal connection
    conversation = Connect(host, port)
    node = conversation
    ciphers = [CipherSuite.TLS_RSA_WITH_AES_128_CBC_SHA,
               CipherSuite.TLS_EMPTY_RENEGOTIATION_INFO_SCSV]
    node = node.add_child(ClientHelloGenerator(ciphers, version=(3, 0)))
    node = node.add_child(ExpectServerHello())
    node = node.add_child(ExpectCertificate())
    node = node.add_child(ExpectServerHelloDone())
    node = node.add_child(ClientKeyExchangeGenerator())
    node = node.add_child(ChangeCipherSpecGenerator())
    node = node.add_child(FinishedGenerator())
    node = node.add_child(ExpectChangeCipherSpec())
    node = node.add_child(ExpectFinished())
    text = b"GET / HTTP/1.0\nX-bad: aaaa\n\n"
    node = node.add_child(ApplicationDataGenerator(text))
    node = node.add_child(ExpectApplicationData())
    # BEAST 1/n-1 splitting
    node = node.add_child(ExpectApplicationData())
    node = node.add_child(AlertGenerator(AlertLevel.warning,
                                         AlertDescription.close_notify))
    node = node.add_child(ExpectAlert(AlertLevel.warning,
                                      AlertDescription.close_notify))
    node.next_sibling = ExpectClose()
    node = node.add_child(ExpectClose())

    conversations["sanity"] = \
            conversation

    # zero-fill SSLv3 padding
    conversation = Connect(host, port)
    node = conversation
    ciphers = [CipherSuite.TLS_RSA_WITH_AES_128_CBC_SHA,
               CipherSuite.TLS_EMPTY_RENEGOTIATION_INFO_SCSV]
    node = node.add_child(ClientHelloGenerator(ciphers, version=(3, 0)))
    node = node.add_child(ExpectServerHello())
    node = node.add_child(ExpectCertificate())
    node = node.add_child(ExpectServerHelloDone())
    node = node.add_child(ClientKeyExchangeGenerator())
    node = node.add_child(ChangeCipherSpecGenerator())
    node = node.add_child(FinishedGenerator())
    node = node.add_child(ExpectChangeCipherSpec())
    node = node.add_child(ExpectFinished())
    text = b"GET / HTTP/1.0\nX-bad: aaaa\n\n"
    hmac_tag_length = 20  # because we're using HMAC-SHA-1
    block_size = 16  # because we're suing AES
    # make sure that padding has full block to work with
    assert (len(text) + hmac_tag_length) % block_size == 0
    node = node.add_child(fuzz_padding(ApplicationDataGenerator(text),
                                       # set all bytes of pad to b'\x00'
                                       # with exception of the length byte
                                       substitutions=dict(
                                           (x, 0) for x in range(0, 15))))
    node = node.add_child(ExpectApplicationData())
    # BEAST 1/n-1 splitting
    node = node.add_child(ExpectApplicationData())
    node = node.add_child(AlertGenerator(AlertLevel.warning,
                                         AlertDescription.close_notify))
    node = node.add_child(ExpectAlert(AlertLevel.warning,
                                      AlertDescription.close_notify))
    node.next_sibling = ExpectClose()
    node = node.add_child(ExpectClose())

    conversations["zero-filled padding in SSLv3"] = \
            conversation

    # max size SSLv3 padding
    conversation = Connect(host, port)
    node = conversation
    ciphers = [CipherSuite.TLS_RSA_WITH_AES_128_CBC_SHA,
               CipherSuite.TLS_EMPTY_RENEGOTIATION_INFO_SCSV]
    node = node.add_child(ClientHelloGenerator(ciphers, version=(3, 0)))
    node = node.add_child(ExpectServerHello())
    node = node.add_child(ExpectCertificate())
    node = node.add_child(ExpectServerHelloDone())
    node = node.add_child(ClientKeyExchangeGenerator())
    node = node.add_child(ChangeCipherSpecGenerator())
    node = node.add_child(FinishedGenerator())
    node = node.add_child(ExpectChangeCipherSpec())
    node = node.add_child(ExpectFinished())
    text = b"GET / HTTP/1.0\nX-bad: aaaa\n\n"
    hmac_tag_length = 20
    block_size = 16
    # make sure that padding has full block to work with
    assert (len(text) + hmac_tag_length) % block_size == 0
    node = node.add_child(fuzz_padding(ApplicationDataGenerator(text),
                                       min_length=128//8))
    node = node.add_child(ExpectApplicationData())
    # BEAST 1/n-1 splitting
    node = node.add_child(ExpectApplicationData())
    node = node.add_child(AlertGenerator(AlertLevel.warning,
                                         AlertDescription.close_notify))
    node = node.add_child(ExpectAlert(AlertLevel.warning,
                                      AlertDescription.close_notify))
    node.next_sibling = ExpectClose()
    node = node.add_child(ExpectClose())

    conversations["max acceptable padding in SSLv3"] = \
            conversation

    # too much padding in SSLv3
    conversation = Connect(host, port)
    node = conversation
    ciphers = [CipherSuite.TLS_RSA_WITH_AES_128_CBC_SHA,
               CipherSuite.TLS_EMPTY_RENEGOTIATION_INFO_SCSV]
    node = node.add_child(ClientHelloGenerator(ciphers, version=(3, 0)))
    node = node.add_child(ExpectServerHello())
    node = node.add_child(ExpectCertificate())
    node = node.add_child(ExpectServerHelloDone())
    node = node.add_child(ClientKeyExchangeGenerator())
    node = node.add_child(ChangeCipherSpecGenerator())
    node = node.add_child(FinishedGenerator())
    node = node.add_child(ExpectChangeCipherSpec())
    node = node.add_child(ExpectFinished())
    text = b"GET / HTTP/1.0\nX-bad: aaaa\n\n"
    hmac_tag_length = 20
    block_size = 16
    # make sure that padding has full block to work with
    assert (len(text) + hmac_tag_length) % block_size == 0
    node = node.add_child(fuzz_padding(ApplicationDataGenerator(text),
                                       # make the padding longer than the block
                                       # size of the cipher
                                       min_length=(128//8)+1))
    node = node.add_child(ExpectAlert(AlertLevel.fatal,
                                      AlertDescription.bad_record_mac))
    node.add_child(ExpectClose())

    conversations["excessive padding in SSLv3 (valid in TLS 1.0)"] = \
            conversation

    # max size SSLv3 padding
    conversation = Connect(host, port)
    node = conversation
    ciphers = [CipherSuite.TLS_RSA_WITH_AES_128_CBC_SHA,
               CipherSuite.TLS_EMPTY_RENEGOTIATION_INFO_SCSV]
    node = node.add_child(ClientHelloGenerator(ciphers, version=(3, 0)))
    node = node.add_child(ExpectServerHello())
    node = node.add_child(ExpectCertificate())
    node = node.add_child(ExpectServerHelloDone())
    node = node.add_child(ClientKeyExchangeGenerator())
    node = node.add_child(ChangeCipherSpecGenerator())
    node = node.add_child(FinishedGenerator())
    node = node.add_child(ExpectChangeCipherSpec())
    node = node.add_child(ExpectFinished())
    text = b"GET / HTTP/1.0\r\nX-bad: a\r\n"
    # some servers put limits on size of headers, e.g. Apache 2.3 has 8190 Bytes
    for i in range(3):
        text += b"X-ba" + compatAscii2Bytes(str(i)) + b": " + \
                b"a" * (4096 - 9) + b"\r\n"
    text += b"X-ba3: " + b"a" * (4096 - 37) + b"\r\n"
    text += b"\r\n"
    assert len(text) == 2**14, len(text)
    # as SSLv3 specifies that padding must be minimal length, that means
    # there is just one valid length of padding, no need to force it
    node = node.add_child(ApplicationDataGenerator(text))
    node = node.add_child(ExpectApplicationData())
    # BEAST 1/n-1 splitting
    node = node.add_child(ExpectApplicationData())
    node = node.add_child(AlertGenerator(AlertLevel.warning,
                                         AlertDescription.close_notify))
    node = node.add_child(ExpectAlert(AlertLevel.warning,
                                      AlertDescription.close_notify))
    node.next_sibling = ExpectClose()
    node = node.add_child(ExpectClose())

    conversations["max Application Data in SSLv3"] = \
            conversation


    # run the conversation
    good = 0
    bad = 0
    xfail = 0
    xpass = 0
    failed = []
    xpassed = []
    if not num_limit:
        num_limit = len(conversations)

    # make sure that sanity test is run first and last
    # to verify that server was running and kept running throughout
    sanity_tests = [('sanity', conversations['sanity'])]
    if run_only:
        if num_limit > len(run_only):
            num_limit = len(run_only)
        regular_tests = [(k, v) for k, v in conversations.items() if
                          k in run_only]
    else:
        regular_tests = [(k, v) for k, v in conversations.items() if
                         (k != 'sanity') and k not in run_exclude]
    sampled_tests = sample(regular_tests, min(num_limit, len(regular_tests)))
    ordered_tests = chain(sanity_tests, sampled_tests, sanity_tests)

    for c_name, c_test in ordered_tests:
        if run_only and c_name not in run_only or c_name in run_exclude:
            continue
        print("{0} ...".format(c_name))

        runner = Runner(c_test)

        res = True
        exception = None
        try:
            runner.run()
        except Exception as exp:
            exception = exp
            print("Error while processing")
            print(traceback.format_exc())
            res = False

        if c_name in expected_failures:
            if res:
                xpass += 1
                xpassed.append(c_name)
                print("XPASS-expected failure but test passed\n")
            else:
                if expected_failures[c_name] is not None and  \
                    expected_failures[c_name] not in str(exception):
                        bad += 1
                        failed.append(c_name)
                        print("Expected error message: {0}\n"
                            .format(expected_failures[c_name]))
                else:
                    xfail += 1
                    print("OK-expected failure\n")
        else:
            if res:
                good += 1
                print("OK\n")
            else:
                bad += 1
                failed.append(c_name)

    print("Script to verify different padding scenarios in SSLv3.")
    print("Check if the padding in SSLv3 follows the RFC6101\n")

    print("Test end")
    print(20 * '=')
    print("version: {0}".format(version))
    print(20 * '=')
    print("TOTAL: {0}".format(len(sampled_tests) + 2*len(sanity_tests)))
    print("SKIP: {0}".format(len(run_exclude.intersection(conversations.keys()))))
    print("PASS: {0}".format(good))
    print("XFAIL: {0}".format(xfail))
    print("FAIL: {0}".format(bad))
    print("XPASS: {0}".format(xpass))
    print(20 * '=')
    sort = sorted(xpassed ,key=natural_sort_keys)
    if len(sort):
        print("XPASSED:\n\t{0}".format('\n\t'.join(repr(i) for i in sort)))
    sort = sorted(failed, key=natural_sort_keys)
    if len(sort):
        print("FAILED:\n\t{0}".format('\n\t'.join(repr(i) for i in sort)))

    if bad or xpass:
        sys.exit(1)

if __name__ == "__main__":
    main()