Merge remote-tracking branch 'public/bug11513_024' into maint-0.2.4

  o Major bugfixes:

    - Generate the server's preference list for ciphersuites

      automatically based on uniform criteria, and considering all

      OpenSSL ciphersuites with acceptable strength and forward

      secrecy. (The sort order is: prefer AES to 3DES; break ties by

      preferring ECDHE to DHE; break ties by preferring GCM to CBC;

      break ties by preferring SHA384 to SHA256 to SHA1; and finally,

      break ties by preferring AES256 to AES128.) This resolves bugs

      #11513, #11492, #11498, #11499. Bugs reported by 'cypherpunks'.

      Bugfix on 0.2.4.8-alpha.

#!/usr/bin/python

# Copyright 2014, The Tor Project, Inc

# See LICENSE for licensing information

# This script parses openssl headers to find ciphersuite names, determines

# which ones we should be willing to use as a server, and sorts them according

# to preference rules.

#

# Run it on all the files in your openssl include directory.

import re

import sys

EPHEMERAL_INDICATORS = [ "_EDH_", "_DHE_", "_ECDHE_" ]

BAD_STUFF = [ "_DES_40_", "MD5", "_RC4_", "_DES_64_",

              "_SEED_", "_CAMELLIA_", "_NULL" ]

# these never get #ifdeffed.

MANDATORY = [

    "TLS1_TXT_DHE_RSA_WITH_AES_256_SHA",

    "TLS1_TXT_DHE_RSA_WITH_AES_128_SHA",

    "SSL3_TXT_EDH_RSA_DES_192_CBC3_SHA",

]

def find_ciphers(filename):

    with open(filename) as f:

        for line in f:

            m = re.search(r'(?:SSL3|TLS1)_TXT_\w+', line)

            if m:

                yield m.group(0)

def usable_cipher(ciph):

    ephemeral = False

    for e in EPHEMERAL_INDICATORS:

        if e in ciph:

            ephemeral = True

    if not ephemeral:

        return False

    if "_RSA_" not in ciph:

        return False

    for b in BAD_STUFF:

        if b in ciph:

            return False

    return True

# All fields we sort on, in order of priority.

FIELDS = [ 'cipher', 'fwsec', 'mode',  'digest', 'bitlength' ]

# Map from sorted fields to recognized value in descending order of goodness

FIELD_VALS = { 'cipher' : [ 'AES', 'DES'],

               'fwsec' : [ 'ECDHE', 'DHE' ],

               'mode' : [ 'GCM', 'CBC' ],

               'digest' : [ 'SHA384', 'SHA256', 'SHA' ],

               'bitlength' : [ '256', '128', '192' ],

}

class Ciphersuite(object):

    def __init__(self, name, fwsec, cipher, bitlength, mode, digest):

        self.name = name

        self.fwsec = fwsec

        self.cipher = cipher

        self.bitlength = bitlength

        self.mode = mode

        self.digest = digest

        for f in FIELDS:

            assert(getattr(self, f) in FIELD_VALS[f])

    def sort_key(self):

        return tuple(FIELD_VALS[f].index(getattr(self,f)) for f in FIELDS)

def parse_cipher(ciph):

    m = re.match('(?:TLS1|SSL3)_TXT_(EDH|DHE|ECDHE)_RSA(?:_WITH)?_(AES|DES)_(256|128|192)(|_CBC|_CBC3|_GCM)_(SHA|SHA256|SHA384)$', ciph)

    if not m:

        print "/* Couldn't parse %s ! */"%ciph

        return None

    fwsec, cipher, bits, mode, digest = m.groups()

    if fwsec == 'EDH':

        fwsec = 'DHE'

    if mode in [ '_CBC3', '_CBC', '' ]:

        mode = 'CBC'

    elif mode == '_GCM':

        mode = 'GCM'

    return Ciphersuite(ciph, fwsec, cipher, bits, mode, digest)

ALL_CIPHERS = []

for fname in sys.argv[1:]:

    ALL_CIPHERS += (parse_cipher(c)

                           for c in find_ciphers(fname)

                           if usable_cipher(c) )

ALL_CIPHERS.sort(key=Ciphersuite.sort_key)

for c in ALL_CIPHERS:

    if c is ALL_CIPHERS[-1]:

        colon = ';'

    else:

        colon = ' ":"'

    if c.name in MANDATORY:

        print "       /* Required */"

        print '       %s%s'%(c.name,colon)

    else:

        print "#ifdef %s"%c.name

        print '       %s%s'%(c.name,colon)

        print "#endif"

/** List of ciphers that servers should select from when we actually have

 * our choice of what cipher to use. */

const char UNRESTRICTED_SERVER_CIPHER_LIST[] =

#ifdef TLS1_TXT_ECDHE_RSA_WITH_AES_256_CHC_SHA

       TLS1_TXT_ECDHE_RSA_WITH_AES_256_CBC_SHA ":"

#endif

  /* This list is autogenerated with the gen_server_ciphers.py script;

   * don't hand-edit it. */

#ifdef TLS1_TXT_ECDHE_RSA_WITH_AES_256_GCM_SHA384

       TLS1_TXT_ECDHE_RSA_WITH_AES_256_GCM_SHA384 ":"

#endif

#ifdef TLS1_TXT_ECDHE_RSA_WITH_AES_128_GCM_SHA256

       TLS1_TXT_ECDHE_RSA_WITH_AES_128_GCM_SHA256 ":"

#endif

#ifdef TLS1_TXT_ECDHE_RSA_WITH_AES_256_SHA384

       TLS1_TXT_ECDHE_RSA_WITH_AES_256_SHA384 ":"

#endif

#ifdef TLS1_TXT_ECDHE_RSA_WITH_AES_128_SHA256

       TLS1_TXT_ECDHE_RSA_WITH_AES_128_SHA256 ":"

#endif

#ifdef TLS1_TXT_ECDHE_RSA_WITH_AES_256_CBC_SHA

       TLS1_TXT_ECDHE_RSA_WITH_AES_256_CBC_SHA ":"

#endif

#ifdef TLS1_TXT_ECDHE_RSA_WITH_AES_128_CBC_SHA

       TLS1_TXT_ECDHE_RSA_WITH_AES_128_CBC_SHA ":"

#endif

#ifdef TLS1_TXT_ECDHE_RSA_WITH_AES_128_GCM_SHA256

       TLS1_TXT_ECDHE_RSA_WITH_AES_128_GCM_SHA256

#ifdef TLS1_TXT_DHE_RSA_WITH_AES_256_GCM_SHA384

       TLS1_TXT_DHE_RSA_WITH_AES_256_GCM_SHA384 ":"

#endif

#ifdef TLS1_TXT_DHE_RSA_WITH_AES_128_GCM_SHA256

       TLS1_TXT_DHE_RSA_WITH_AES_128_GCM_SHA256 ":"

#endif

#ifdef TLS1_TXT_DHE_RSA_WITH_AES_256_SHA256

       TLS1_TXT_DHE_RSA_WITH_AES_256_SHA256 ":"

#endif

#ifdef TLS1_TXT_DHE_RSA_WITH_AES_128_SHA256

       TLS1_TXT_DHE_RSA_WITH_AES_128_SHA256 ":"

#endif

//#if TLS1_TXT_ECDHE_RSA_WITH_RC4_128_SHA

//    TLS1_TXT_ECDHE_RSA_WITH_RC4_128_SHA ":"

//#endif

  /* These next two are mandatory. */

       /* Required */

       TLS1_TXT_DHE_RSA_WITH_AES_256_SHA ":"

       /* Required */

       TLS1_TXT_DHE_RSA_WITH_AES_128_SHA ":"

#ifdef TLS1_TXT_ECDHE_RSA_WITH_DES_192_CBC3_SHA

       TLS1_TXT_ECDHE_RSA_WITH_DES_192_CBC3_SHA ":"

#endif

       /* Required */

       SSL3_TXT_EDH_RSA_DES_192_CBC3_SHA;

/* Note: to set up your own private testing network with link crypto