# Author: Hubert Kario, (c) 2015-2019
# Released under Gnu GPL v2.0, see LICENSE file for details
"""Test for CVE-2015-7575 (SLOTH)"""

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, \
        CertificateGenerator, CertificateVerifyGenerator, \
        AlertGenerator
from tlsfuzzer.expect import ExpectServerHello, ExpectCertificate, \
        ExpectServerHelloDone, ExpectChangeCipherSpec, ExpectFinished, \
        ExpectAlert, ExpectClose, ExpectCertificateRequest, \
        ExpectApplicationData, ExpectServerKeyExchange
from tlslite.extensions import SignatureAlgorithmsExtension, \
        SignatureAlgorithmsCertExtension, SupportedGroupsExtension
from tlslite.constants import CipherSuite, AlertDescription, \
        HashAlgorithm, SignatureAlgorithm, ExtensionType, GroupName
from tlslite.utils.keyfactory import parsePEMKey
from tlslite.x509 import X509
from tlslite.x509certchain import X509CertChain
from tlsfuzzer.utils.lists import natural_sort_keys
from tlsfuzzer.helpers import RSA_SIG_ALL, AutoEmptyExtension


version = 11


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(" -k file.pem    file with private key for client")
    print(" -c file.pem    file with certificate for client")
    print(" -d             negotiate (EC)DHE instead of RSA key exchange")
    print(" -C ciph        Use specified ciphersuite. Either numerical value or")
    print("                IETF name.")
    print(" -M | --ems     Enable support for Extended Master Secret")
    print(" --help         this message")


def main():
    """check if obsolete signature algorithm is rejected by server"""
    host = "localhost"
    port = 4433
    num_limit = None
    run_exclude = set()
    expected_failures = {}
    last_exp_tmp = None
    private_key = None
    cert = None
    dhe = False
    ciphers = None
    ems = False

    argv = sys.argv[1:]
    opts, args = getopt.getopt(argv, "h:p:e:x:X:n:k:c:dC:M", ["help", "ems"])
    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 == '-d':
            dhe = True
        elif opt == '-C':
            if arg[:2] == '0x':
                ciphers = [int(arg, 16)]
            else:
                try:
                    ciphers = [getattr(CipherSuite, arg)]
                except AttributeError:
                    ciphers = [int(arg)]
        elif opt == '--help':
            help_msg()
            sys.exit(0)
        elif opt == '-k':
            text_key = open(arg, 'rb').read()
            if sys.version_info[0] >= 3:
                text_key = str(text_key, 'utf-8')
            private_key = parsePEMKey(text_key, private=True)
        elif opt == '-c':
            text_cert = open(arg, 'rb').read()
            if sys.version_info[0] >= 3:
                text_cert = str(text_cert, 'utf-8')
            cert = X509()
            cert.parse(text_cert)
        elif opt == '-M' or opt == '--ems':
            ems = True
        else:
            raise ValueError("Unknown option: {0}".format(opt))

    if not private_key:
        raise ValueError("Specify private key file using -k")
    if not cert:
        raise ValueError("Specify certificate file using -c")

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

    if ciphers:
        if not dhe:
            # by default send minimal set of extensions, but allow user
            # to override it
            dhe = ciphers[0] in CipherSuite.ecdhAllSuites or \
                    ciphers[0] in CipherSuite.dhAllSuites
    else:
        if dhe:
            ciphers = [CipherSuite.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA,
                       CipherSuite.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
                       CipherSuite.TLS_DHE_RSA_WITH_AES_128_CBC_SHA]
        else:
            ciphers = [CipherSuite.TLS_RSA_WITH_AES_128_CBC_SHA]
    ciphers.append(CipherSuite.TLS_EMPTY_RENEGOTIATION_INFO_SCSV)

    conversations = {}

    # sanity check for Client Certificates
    conversation = Connect(host, port)
    node = conversation
    ext = {ExtensionType.signature_algorithms :
           SignatureAlgorithmsExtension().create([
             (getattr(HashAlgorithm, x),
              SignatureAlgorithm.rsa) for x in ['sha512', 'sha384', 'sha256',
                                                'sha224', 'sha1', 'md5']]),
           ExtensionType.signature_algorithms_cert :
           SignatureAlgorithmsCertExtension().create(RSA_SIG_ALL)}
    if dhe:
        groups = [GroupName.secp256r1,
                  GroupName.ffdhe2048]
        ext[ExtensionType.supported_groups] = SupportedGroupsExtension()\
            .create(groups)
    if ems:
        ext[ExtensionType.extended_master_secret] = AutoEmptyExtension()
    node = node.add_child(ClientHelloGenerator(ciphers, extensions=ext))
    node = node.add_child(ExpectServerHello(version=(3, 3)))
    node = node.add_child(ExpectCertificate())
    if dhe:
        node = node.add_child(ExpectServerKeyExchange())
    node = node.add_child(ExpectCertificateRequest())
    node = node.add_child(ExpectServerHelloDone())
    node = node.add_child(CertificateGenerator(X509CertChain([cert])))
    node = node.add_child(ClientKeyExchangeGenerator())
    node = node.add_child(CertificateVerifyGenerator(private_key))
    node = node.add_child(ChangeCipherSpecGenerator())
    node = node.add_child(FinishedGenerator())
    node = node.add_child(ExpectChangeCipherSpec())
    node = node.add_child(ExpectFinished())
    node = node.add_child(ApplicationDataGenerator(b"GET / HTTP/1.0\n\n"))
    node = node.add_child(ExpectApplicationData())
    node = node.add_child(AlertGenerator(AlertDescription.close_notify))
    node = node.add_child(ExpectClose())
    node.next_sibling = ExpectAlert()
    node.next_sibling.add_child(ExpectClose())

    conversations["sanity"] = conversation

    # force MD5 signature on CertificateVerify
    conversation = Connect(host, port)
    node = conversation
    ext = {ExtensionType.signature_algorithms :
           SignatureAlgorithmsExtension().create([
             (getattr(HashAlgorithm, x),
              SignatureAlgorithm.rsa) for x in ['sha512', 'sha384', 'sha256',
                                                'sha224', 'sha1', 'md5']]),
           ExtensionType.signature_algorithms_cert :
           SignatureAlgorithmsCertExtension().create(RSA_SIG_ALL)}
    if dhe:
        groups = [GroupName.secp256r1,
                  GroupName.ffdhe2048]
        ext[ExtensionType.supported_groups] = SupportedGroupsExtension()\
            .create(groups)
    if ems:
        ext[ExtensionType.extended_master_secret] = AutoEmptyExtension()
    node = node.add_child(ClientHelloGenerator(ciphers, extensions=ext))
    node = node.add_child(ExpectServerHello(version=(3, 3)))
    node = node.add_child(ExpectCertificate())
    if dhe:
        node = node.add_child(ExpectServerKeyExchange())
    node = node.add_child(ExpectCertificateRequest())
    node = node.add_child(ExpectServerHelloDone())
    node = node.add_child(CertificateGenerator(X509CertChain([cert])))
    node = node.add_child(ClientKeyExchangeGenerator())
    sig_type = (HashAlgorithm.md5, SignatureAlgorithm.rsa)
    node = node.add_child(CertificateVerifyGenerator(private_key,
                                                     msg_alg=sig_type
                                                     ))
    # the other side can close connection right away, add options to handle it
    node.next_sibling = ExpectClose()
    node = node.add_child(ChangeCipherSpecGenerator())
    node.next_sibling = ExpectClose()
    node = node.add_child(FinishedGenerator())
    node.next_sibling = ExpectClose()
    # we expect closure or Alert and then closure of socket
    node = node.add_child(ExpectClose())
    node.next_sibling = ExpectAlert()
    node.next_sibling.add_child(ExpectClose())

    conversations["MD5 forced"] = conversation

    # place a real MD5 signature in CertificateVerify, but indicate a normal
    # (requested by server) in the outside structure - tests if the server
    # parses the HashInfo structure from signature or if it compares it with
    # expected value
    conversation = Connect(host, port)
    node = conversation
    ext = {ExtensionType.signature_algorithms :
           SignatureAlgorithmsExtension().create([
             (getattr(HashAlgorithm, x),
              SignatureAlgorithm.rsa) for x in ['sha512', 'sha384', 'sha256',
                                                'sha224', 'sha1', 'md5']]),
           ExtensionType.signature_algorithms_cert :
           SignatureAlgorithmsCertExtension().create(RSA_SIG_ALL)}
    if dhe:
        groups = [GroupName.secp256r1,
                  GroupName.ffdhe2048]
        ext[ExtensionType.supported_groups] = SupportedGroupsExtension()\
            .create(groups)
    if ems:
        ext[ExtensionType.extended_master_secret] = AutoEmptyExtension()
    node = node.add_child(ClientHelloGenerator(ciphers, extensions=ext))
    node = node.add_child(ExpectServerHello(version=(3, 3)))
    node = node.add_child(ExpectCertificate())
    if dhe:
        node = node.add_child(ExpectServerKeyExchange())
    node = node.add_child(ExpectCertificateRequest())
    node = node.add_child(ExpectServerHelloDone())
    node = node.add_child(CertificateGenerator(X509CertChain([cert])))
    node = node.add_child(ClientKeyExchangeGenerator())
    sig_type = (HashAlgorithm.md5, SignatureAlgorithm.rsa)
    node = node.add_child(CertificateVerifyGenerator(private_key,
                                                     sig_alg=sig_type
                                                     ))
    # the other side can close connection right away, add options to handle it
    node.next_sibling = ExpectClose()
    node = node.add_child(ChangeCipherSpecGenerator())
    node.next_sibling = ExpectClose()
    node = node.add_child(FinishedGenerator())
    node.next_sibling = ExpectClose()
    # we expect closure or Alert and then closure of socket
    node = node.add_child(ExpectClose())
    node.next_sibling = ExpectAlert()
    node.next_sibling.add_child(ExpectClose())

    conversations["MD5 forced in HashInfo"] = conversation

    # make invalid signature in CertificateVerify (TLSv1.1 style)
    conversation = Connect(host, port)
    node = conversation
    ext = {ExtensionType.signature_algorithms :
           SignatureAlgorithmsExtension().create([
             (getattr(HashAlgorithm, x),
              SignatureAlgorithm.rsa) for x in ['sha512', 'sha384', 'sha256',
                                                'sha224', 'sha1', 'md5']]),
           ExtensionType.signature_algorithms_cert :
           SignatureAlgorithmsCertExtension().create(RSA_SIG_ALL)}
    if dhe:
        groups = [GroupName.secp256r1,
                  GroupName.ffdhe2048]
        ext[ExtensionType.supported_groups] = SupportedGroupsExtension()\
            .create(groups)
    if ems:
        ext[ExtensionType.extended_master_secret] = AutoEmptyExtension()
    node = node.add_child(ClientHelloGenerator(ciphers, extensions=ext))
    node = node.add_child(ExpectServerHello(version=(3, 3)))
    node = node.add_child(ExpectCertificate())
    if dhe:
        node = node.add_child(ExpectServerKeyExchange())
    node = node.add_child(ExpectCertificateRequest())
    node = node.add_child(ExpectServerHelloDone())
    node = node.add_child(CertificateGenerator(X509CertChain([cert])))
    node = node.add_child(ClientKeyExchangeGenerator())
    node = node.add_child(CertificateVerifyGenerator(private_key,
                                                     sig_version=(3, 2)
                                                     ))
    # the other side can close connection right away, add options to handle it
    node.next_sibling = ExpectClose()
    node = node.add_child(ChangeCipherSpecGenerator())
    node.next_sibling = ExpectClose()
    node = node.add_child(FinishedGenerator())
    node.next_sibling = ExpectClose()
    # we expect closure or Alert and then closure of socket
    node = node.add_child(ExpectClose())
    node.next_sibling = ExpectAlert()
    node.next_sibling.add_child(ExpectClose())

    conversations["TLSv1.1 signature in TLSv1.2 Certificate Verify"] = \
            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("MD5 CertificateVerify (CVE-2015-7575 aka SLOTH) test\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()
