# Author: Hubert Kario, (c) 2018
# Released under Gnu GPL v2.0, see LICENSE file for details

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, \
        FinishedGenerator, ApplicationDataGenerator, AlertGenerator, \
        CopyVariables
from tlsfuzzer.expect import ExpectServerHello, ExpectCertificate, \
        ExpectChangeCipherSpec, ExpectFinished, \
        ExpectAlert, ExpectApplicationData, ExpectClose, \
        ExpectEncryptedExtensions, ExpectCertificateVerify, \
        ExpectNewSessionTicket
from tlsfuzzer.utils.lists import natural_sort_keys
from tlsfuzzer.helpers import RSA_SIG_ALL, key_share_ext_gen

from tlslite.constants import CipherSuite, AlertLevel, AlertDescription, \
        TLS_1_3_DRAFT, GroupName, ExtensionType, SignatureScheme
from tlslite.extensions import \
        SupportedVersionsExtension, SupportedGroupsExtension, \
        SignatureAlgorithmsExtension, SignatureAlgorithmsCertExtension


"""Script to verify that the DH keys are computed correctly."""


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(1)")
    print("                (excluding \"sanity\" tests)")
    print(" --min-zeros num number of zeros that need to be found in the")
    print("                shared secret for the test case to be considered")
    print("                good. 1 by default")
    print(" --help         this message")


def main():
    host = "localhost"
    port = 4433
    num_limit = 1
    run_exclude = set()
    expected_failures = {}
    last_exp_tmp = None
    min_zeros = 1

    argv = sys.argv[1:]
    opts, args = getopt.getopt(argv, "h:p:e:x:X:n:", ["help", "min-zeros="])
    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)
        elif opt == '--min-zeros':
            min_zeros = int(arg)
        else:
            raise ValueError("Unknown option: {0}".format(opt))

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

    collected_shared_secrets = []
    collected_key_shares = []
    variables_check = \
        {'DH shared secret':
         collected_shared_secrets,
         'ServerHello.extensions.key_share.key_exchange':
         collected_key_shares}

    conversations = {}

    conversation = Connect(host, port)
    node = conversation
    ciphers = [CipherSuite.TLS_AES_128_GCM_SHA256,
               CipherSuite.TLS_EMPTY_RENEGOTIATION_INFO_SCSV]
    ext = {}
    groups = [GroupName.secp256r1]
    ext[ExtensionType.key_share] = key_share_ext_gen(groups)
    ext[ExtensionType.supported_versions] = SupportedVersionsExtension()\
        .create([TLS_1_3_DRAFT, (3, 3)])
    ext[ExtensionType.supported_groups] = SupportedGroupsExtension()\
        .create(groups)
    sig_algs = [SignatureScheme.rsa_pss_rsae_sha256,
                SignatureScheme.rsa_pss_pss_sha256]
    ext[ExtensionType.signature_algorithms] = SignatureAlgorithmsExtension()\
        .create(sig_algs)
    ext[ExtensionType.signature_algorithms_cert] = SignatureAlgorithmsCertExtension()\
        .create(RSA_SIG_ALL)
    node = node.add_child(ClientHelloGenerator(ciphers, extensions=ext))
    node = node.add_child(ExpectServerHello())
    node = node.add_child(CopyVariables(variables_check))
    node = node.add_child(ExpectChangeCipherSpec())
    node = node.add_child(ExpectEncryptedExtensions())
    node = node.add_child(ExpectCertificate())
    node = node.add_child(ExpectCertificateVerify())
    node = node.add_child(ExpectFinished())
    node = node.add_child(FinishedGenerator())
    node = node.add_child(ApplicationDataGenerator(
        bytearray(b"GET / HTTP/1.0\r\n\r\n")))

    # This message is optional and may show up 0 to many times
    cycle = ExpectNewSessionTicket()
    node = node.add_child(cycle)
    node.add_child(cycle)

    node.next_sibling = ExpectApplicationData()
    node = node.next_sibling.add_child(
        AlertGenerator(AlertLevel.warning,
                       AlertDescription.close_notify))

    node = node.add_child(ExpectAlert())
    node.next_sibling = ExpectClose()
    conversations["sanity"] = conversation

    for group in [GroupName.secp384r1, GroupName.secp521r1, GroupName.x25519,
                  GroupName.x448, GroupName.ffdhe2048, GroupName.ffdhe3072]:
        conversation = Connect(host, port)
        node = conversation
        ciphers = [CipherSuite.TLS_AES_128_GCM_SHA256,
                   CipherSuite.TLS_EMPTY_RENEGOTIATION_INFO_SCSV]
        ext = {}
        groups = [group]
        ext[ExtensionType.key_share] = key_share_ext_gen(groups)
        ext[ExtensionType.supported_versions] = SupportedVersionsExtension()\
            .create([TLS_1_3_DRAFT, (3, 3)])
        ext[ExtensionType.supported_groups] = SupportedGroupsExtension()\
            .create(groups)
        sig_algs = [SignatureScheme.rsa_pss_rsae_sha256,
                    SignatureScheme.rsa_pss_pss_sha256]
        ext[ExtensionType.signature_algorithms] = SignatureAlgorithmsExtension()\
            .create(sig_algs)
        ext[ExtensionType.signature_algorithms_cert] = SignatureAlgorithmsCertExtension()\
            .create(RSA_SIG_ALL)
        node = node.add_child(ClientHelloGenerator(ciphers, extensions=ext))
        node = node.add_child(ExpectServerHello())
        node = node.add_child(CopyVariables(variables_check))
        node = node.add_child(ExpectChangeCipherSpec())
        node = node.add_child(ExpectEncryptedExtensions())
        node = node.add_child(ExpectCertificate())
        node = node.add_child(ExpectCertificateVerify())
        node = node.add_child(ExpectFinished())
        node = node.add_child(FinishedGenerator())
        node = node.add_child(ApplicationDataGenerator(
            bytearray(b"GET / HTTP/1.0\r\n\r\n")))

        # This message is optional and may show up 0 to many times
        cycle = ExpectNewSessionTicket()
        node = node.add_child(cycle)
        node.add_child(cycle)

        node.next_sibling = ExpectApplicationData()
        node = node.next_sibling.add_child(
            AlertGenerator(AlertLevel.warning,
                           AlertDescription.close_notify))

        node = node.add_child(ExpectAlert())
        node.next_sibling = ExpectClose()
        conversations["TLS 1.3 with {0}".format(GroupName.toStr(group))] \
            = 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
        i = 0
        break_shared = False
        break_key_share = False
        while True:
            # don't hog the memory unnecessairly
            collected_shared_secrets[:] = []
            print("\"{1}\" repeat {0}...".format(i, c_name))
            i += 1
            if c_name == 'sanity':
                break_shared = True
                break_key_share = True

            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")
                    break
            else:
                if res:
                    good += 1
                    if collected_shared_secrets[-1][:min_zeros] == \
                            bytearray(min_zeros):
                        print("Got shared secret with {0} most significant "
                                "bytes equal to zero."
                                .format(min_zeros))
                        break_shared = True
                    # ECDSA key shares have a constant first byte indicating
                    # the point encoding
                    if "secp" in c_name:
                        if collected_key_shares[-1][:min_zeros+1] == \
                                bytearray(b'\x04') + bytearray(min_zeros):
                            print("Got key share with {0} most significant bytes equal"
                                  " to zero.".format(min_zeros))
                            break_key_share = True
                    else:
                        if collected_key_shares[-1][:min_zeros] == \
                                bytearray(min_zeros):
                            print("Got key share with {0} most significant bytes equal"
                                  " to zero.".format(min_zeros))
                            break_key_share = True
                    print("OK\n")
                else:
                    bad += 1
                    failed.append(c_name)
                    break

                if break_shared and break_key_share:
                    break

    print('')

    print("Check if the connections work when the calculated DH shared secret")
    print("must be padded on the left with zeros or when the server needs")
    print("to pad its key share")

    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()