diff options
Diffstat (limited to 'sleekxmpp/util/sasl')
| -rw-r--r-- | sleekxmpp/util/sasl/__init__.py | 15 | ||||
| -rw-r--r-- | sleekxmpp/util/sasl/client.py | 163 | ||||
| -rw-r--r-- | sleekxmpp/util/sasl/mechanisms.py | 531 |
3 files changed, 709 insertions, 0 deletions
diff --git a/sleekxmpp/util/sasl/__init__.py b/sleekxmpp/util/sasl/__init__.py new file mode 100644 index 00000000..d054ce09 --- /dev/null +++ b/sleekxmpp/util/sasl/__init__.py @@ -0,0 +1,15 @@ +# -*- coding: utf-8 -*- +""" + sleekxmpp.util.sasl + ~~~~~~~~~~~~~~~~~~~ + + This module was originally based on Dave Cridland's Suelta library. + + Part of SleekXMPP: The Sleek XMPP Library + + :copyright: (c) 2012 Nathanael C. Fritz, Lance J.T. Stout + :license: MIT, see LICENSE for more details +""" + +from sleekxmpp.util.sasl.client import * +from sleekxmpp.util.sasl.mechanisms import * diff --git a/sleekxmpp/util/sasl/client.py b/sleekxmpp/util/sasl/client.py new file mode 100644 index 00000000..bf05a617 --- /dev/null +++ b/sleekxmpp/util/sasl/client.py @@ -0,0 +1,163 @@ +# -*- coding: utf-8 -*- +""" + sleekxmpp.util.sasl.client + ~~~~~~~~~~~~~~~~~~~~~~~~~~ + + This module was originally based on Dave Cridland's Suelta library. + + Part of SleekXMPP: The Sleek XMPP Library + + :copyright: (c) 2012 Nathanael C. Fritz, Lance J.T. Stout + :license: MIT, see LICENSE for more details +""" + +import stringprep + +from sleekxmpp.util import hashes, bytes, stringprep_profiles + + +#: Global registry mapping mechanism names to implementation classes. +MECHANISMS = {} + + +#: Global registry mapping mechanism names to security scores. +MECH_SEC_SCORES = {} + + +#: The SASLprep profile of stringprep used to validate simple username +#: and password credentials. +saslprep = stringprep_profiles.create( + nfkc=True, + bidi=True, + mappings=[ + stringprep_profiles.b1_mapping, + stringprep_profiles.c12_mapping], + prohibited=[ + stringprep.in_table_c12, + stringprep.in_table_c21, + stringprep.in_table_c22, + stringprep.in_table_c3, + stringprep.in_table_c4, + stringprep.in_table_c5, + stringprep.in_table_c6, + stringprep.in_table_c7, + stringprep.in_table_c8, + stringprep.in_table_c9], + unassigned=[stringprep.in_table_a1]) + + +def sasl_mech(score): + sec_score = score + def register(mech): + n = 0 + mech.score = sec_score + if mech.use_hashes: + for hashing_alg in hashes(): + n += 1 + score = mech.score + n + name = '%s-%s' % (mech.name, hashing_alg) + MECHANISMS[name] = mech + MECH_SEC_SCORES[name] = score + + if mech.channel_binding: + name += '-PLUS' + score += 10 + MECHANISMS[name] = mech + MECH_SEC_SCORES[name] = score + else: + MECHANISMS[mech.name] = mech + MECH_SEC_SCORES[mech.name] = mech.score + if mech.channel_binding: + MECHANISMS[mech.name + '-PLUS'] = mech + MECH_SEC_SCORES[name] = mech.score + 10 + return mech + return register + + +class SASLNoAppropriateMechanism(Exception): + pass + + +class SASLCancelled(Exception): + pass + + +class SASLFailed(Exception): + pass + + +class SASLMutualAuthFailed(SASLFailed): + pass + + +class Mech(object): + + name = 'GENERIC' + score = -1 + use_hashes = False + channel_binding = False + required_credentials = set() + optional_credentials = set() + + def __init__(self, name, credentials, security_settings): + self.credentials = credentials + self.security_settings = security_settings + self.values = {} + self.base_name = self.name + self.name = name + self.setup(name) + + def setup(self, name): + pass + + def process(self, challenge=b''): + return b'' + + +def choose(mech_list, credentials, security_settings, limit=None, min_mech=None): + available_mechs = set(MECHANISMS.keys()) + if limit is None: + limit = set(mech_list) + if not isinstance(limit, set): + limit = set(limit) + if not isinstance(mech_list, set): + mech_list = set(mech_list) + + mech_list = mech_list.intersection(limit) + available_mechs = available_mechs.intersection(mech_list) + + best_score = MECH_SEC_SCORES.get(min_mech, -1) + best_mech = None + for name in available_mechs: + if name in MECH_SEC_SCORES: + if MECH_SEC_SCORES[name] > best_score: + best_score = MECH_SEC_SCORES[name] + best_mech = name + if best_mech is None: + raise SASLNoAppropriateMechanism() + + mech_class = MECHANISMS[best_mech] + + try: + creds = credentials(mech_class.required_credentials, + mech_class.optional_credentials) + for req in mech_class.required_credentials: + if req not in creds: + raise SASLCancelled('Missing credential: %s' % req) + for opt in mech_class.optional_credentials: + if opt not in creds: + creds[opt] = b'' + for cred in creds: + if cred in ('username', 'password', 'authzid'): + creds[cred] = bytes(saslprep(creds[cred])) + else: + creds[cred] = bytes(creds[cred]) + security_opts = security_settings(mech_class.security) + + return mech_class(best_mech, creds, security_opts) + except SASLCancelled as e: + log.debug('SASL: %s: %s', (best_mech, e.message)) + mech_list.remove(best_mech) + return choose(mech_list, credentials, security_settings, + limit=limit, + min_mech=min_mech) diff --git a/sleekxmpp/util/sasl/mechanisms.py b/sleekxmpp/util/sasl/mechanisms.py new file mode 100644 index 00000000..5822a6e4 --- /dev/null +++ b/sleekxmpp/util/sasl/mechanisms.py @@ -0,0 +1,531 @@ +# -*- coding: utf-8 -*- +""" + sleekxmpp.util.sasl.mechanisms + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + + A collection of supported SASL mechanisms. + + This module was originally based on Dave Cridland's Suelta library. + + Part of SleekXMPP: The Sleek XMPP Library + + :copyright: (c) 2012 Nathanael C. Fritz, Lance J.T. Stout + :license: MIT, see LICENSE for more details +""" + +import sys +import hmac +import random + +from base64 import b64encode, b64decode + +from sleekxmpp.util import bytes, hash, XOR, quote, num_to_bytes +from sleekxmpp.util.sasl.client import sasl_mech, Mech, \ + SASLCancelled, SASLFailed + + +@sasl_mech(0) +class ANONYMOUS(Mech): + + name = 'ANONYMOUS' + + def process(self, challenge=b''): + return b'Anonymous, Suelta' + + +@sasl_mech(1) +class LOGIN(Mech): + + name = 'LOGIN' + required_credentials = set(['username', 'password']) + + def setup(self, name): + self.step = 0 + + def process(self, challenge=b''): + if not challenge: + return b'' + + if self.step == 0: + self.step = 1 + return self.credentials['username'] + else: + return self.credentials['password'] + + +@sasl_mech(2) +class PLAIN(Mech): + + name = 'PLAIN' + required_credentials = set(['username', 'password']) + optional_credentials = set(['authzid']) + security = set(['encrypted', 'encrypted_plain', 'unencrypted_plain']) + + def setup(self, name): + if not self.security_settings['encrypted']: + if not self.security_settings['unencrypted_plain']: + raise SASLCancelled('PLAIN without encryption') + else: + if not self.security_settings['encrypted_plain']: + raise SASLCancelled('PLAIN with encryption') + + def process(self, challenge=b''): + authzid = self.credentials['authzid'] + authcid = self.credentials['username'] + password = self.credentials['password'] + return authzid + b'\x00' + authcid + b'\x00' + password + + +@sasl_mech(100) +class EXTERNAL(Mech): + + name = 'EXTERNAL' + optional_credentials = set(['authzid']) + + def process(self, challenge=b''): + return self.credentials['authzid'] + + +@sasl_mech(30) +class X_FACEBOOK_PLATFORM(Mech): + + name = 'X-FACEBOOK-PLATFORM' + required_credentials = set(['api_key', 'access_token']) + + def process(self, challenge=b''): + if challenge: + values = {} + for kv in challenge.split(b'&'): + key, value = kv.split(b'=') + values[key] = value + + resp_data = { + b'method': values[b'method'], + b'v': b'1.0', + b'call_id': b'1.0', + b'nonce': values[b'nonce'], + b'access_token': self.credentials['access_token'], + b'api_key': self.credentials['api_key'] + } + + resp = '&'.join(['%s=%s' % (k, v) for k, v in resp_data.items()]) + return bytes(resp) + return b'' + + +@sasl_mech(10) +class X_MESSENGER_OAUTH2(Mech): + + name = 'X-MESSENGER-OAUTH2' + required_credentials = set(['access_token']) + + def process(self, challenge=b''): + return self.credentials['access_token'] + + +@sasl_mech(3) +class X_GOOGLE_TOKEN(Mech): + + name = 'X-GOOGLE-TOKEN' + required_credentials = set(['email', 'access_token']) + + def process(self, challenge=b''): + email = self.credentials['email'] + token = self.credentials['access_token'] + return b'\x00' + email + b'\x00' + token + + +@sasl_mech(20) +class CRAM(Mech): + + name = 'CRAM' + use_hashes = True + required_credentials = set(['username', 'password']) + security = set(['encrypted', 'unencrypted_cram']) + + def setup(self, name): + self.hash_name = name[5:] + self.hash = hash(self.hash_name) + if self.hash is None: + raise SASLCancelled('Unknown hash: %s' % self.hash_name) + if not self.security_settings['encrypted']: + if not self.security_settings['unencrypted_cram']: + raise SASLCancelled('Unecrypted CRAM-%s' % self.hash_name) + + def process(self, challenge=b''): + if not challenge: + return None + + username = self.credentials['username'] + password = self.credentials['password'] + + mac = hmac.HMAC(key=password, digestmod=self.hash) + mac.update(challenge) + + return username + b' ' + bytes(mac.hexdigest()) + + +@sasl_mech(60) +class SCRAM(Mech): + + name = 'SCRAM' + use_hashes = True + channel_binding = True + required_credentials = set(['username', 'password']) + optional_credentials = set(['authzid', 'channel_binding']) + security = set(['encrypted', 'unencrypted_scram']) + + def setup(self, name): + self.use_channel_binding = False + if name[-5:] == '-PLUS': + name = name[:-5] + self.use_channel_binding = True + + self.hash_name = name[6:] + self.hash = hash(self.hash_name) + + if self.hash is None: + raise SASLCancelled('Unknown hash: %s' % self.hash_name) + if not self.security_settings['encrypted']: + if not self.security_settings['unencrypted_scram']: + raise SASLCancelled('Unencrypted SCRAM') + + self.step = 0 + self._mutual_auth = False + + def HMAC(self, key, msg): + return hmac.HMAC(key=key, msg=msg, digestmod=self.hash).digest() + + def Hi(self, text, salt, iterations): + text = bytes(text) + ui1 = self.HMAC(text, salt + b'\0\0\0\01') + ui = ui1 + for i in range(iterations - 1): + ui1 = self.HMAC(text, ui1) + ui = XOR(ui, ui1) + return ui + + def H(self, text): + return self.hash(text).digest() + + def saslname(self, value): + escaped = b'' + for char in bytes(value): + if char == b',': + escaped += b'=2C' + elif char == b'=': + escaped += b'=3D' + else: + if isinstance(char, int): + char = chr(char) + escaped += bytes(char) + return escaped + + def parse(self, challenge): + items = {} + for key, value in [item.split(b'=', 1) for item in challenge.split(b',')]: + items[key] = value + return items + + def process(self, challenge=b''): + steps = [self.process_1, self.process_2, self.process_3] + return steps[self.step](challenge) + + def process_1(self, challenge): + self.step = 1 + data = {} + + self.cnonce = bytes(('%s' % random.random())[2:]) + + gs2_cbind_flag = b'n' + if self.credentials['channel_binding']: + if self.use_channel_binding: + gs2_cbind_flag = b'p=tls-unique' + else: + gs2_cbind_flag = b'y' + + authzid = b'' + if self.credentials['authzid']: + authzid = b'a=' + self.saslname(self.credentials['authzid']) + + self.gs2_header = gs2_cbind_flag + b',' + authzid + b',' + + nonce = b'r=' + self.cnonce + username = b'n=' + self.saslname(self.credentials['username']) + + self.client_first_message_bare = username + b',' + nonce + self.client_first_message = self.gs2_header + \ + self.client_first_message_bare + + return self.client_first_message + + def process_2(self, challenge): + self.step = 2 + + data = self.parse(challenge) + if b'm' in data: + raise SASLCancelled('Received reserved attribute.') + + salt = b64decode(data[b's']) + iteration_count = int(data[b'i']) + nonce = data[b'r'] + + if nonce[:len(self.cnonce)] != self.cnonce: + raise SASLCancelled('Invalid nonce') + + cbind_data = self.credentials['channel_binding'] + cbind_input = self.gs2_header + cbind_data + channel_binding = b'c=' + b64encode(cbind_input).replace(b'\n', b'') + + client_final_message_without_proof = channel_binding + b',' + \ + b'r=' + nonce + + salted_password = self.Hi(self.credentials['password'], + salt, + iteration_count) + client_key = self.HMAC(salted_password, b'Client Key') + stored_key = self.H(client_key) + auth_message = self.client_first_message_bare + b',' + \ + challenge + b',' + \ + client_final_message_without_proof + client_signature = self.HMAC(stored_key, auth_message) + client_proof = XOR(client_key, client_signature) + server_key = self.HMAC(salted_password, b'Server Key') + + self.server_signature = self.HMAC(server_key, auth_message) + + client_final_message = client_final_message_without_proof + \ + b',p=' + b64encode(client_proof) + + return client_final_message + + def process_3(self, challenge): + data = self.parse(challenge) + verifier = data.get(b'v', None) + error = data.get(b'e', 'Unknown error') + + if not verifier: + raise SASLFailed(error) + + if b64decode(verifier) != self.server_signature: + raise SASLMutualAuthFailed() + + self._mutual_auth = True + + return b'' + + +@sasl_mech(30) +class DIGEST(Mech): + + name = 'DIGEST' + use_hashes = True + required_credentials = set(['username', 'password', 'realm', 'service', 'host']) + optional_credentials = set(['authzid', 'service-name']) + security = set(['encrypted', 'unencrypted_digest']) + + def setup(self, name): + self.hash_name = name[7:] + self.hash = hash(self.hash_name) + if self.hash is None: + raise SASLCancelled('Unknown hash: %s' % self.hash_name) + if not self.security_settings['encrypted']: + if not self.security_settings['unencrypted_digest']: + raise SASLCancelled('Unencrypted DIGEST') + + self.qops = [b'auth'] + self.qop = b'auth' + self.maxbuf = b'65536' + self.nonce = b'' + self.cnonce = b'' + self.nonce_count = 1 + + def parse(self, challenge=b''): + data = {} + var_name = b'' + var_value = b'' + + # States: var, new_var, end, quote, escaped_quote + state = 'var' + + + for char in challenge: + if sys.version_info >= (3, 0): + char = bytes([char]) + + if state == 'var': + if char.isspace(): + continue + if char == b'=': + state = 'value' + else: + var_name += char + elif state == 'value': + if char == b'"': + state = 'quote' + elif char == b',': + if var_name: + data[var_name.decode('utf-8')] = var_value + var_name = b'' + var_value = b'' + state = 'var' + else: + var_value += char + elif state == 'escaped': + var_value += char + elif state == 'quote': + if char == b'\\': + state = 'escaped' + elif char == b'"': + state = 'end' + else: + var_value += char + else: + if char == b',': + if var_name: + data[var_name.decode('utf-8')] = var_value + var_name = b'' + var_value = b'' + state = 'var' + else: + var_value += char + + if var_name: + data[var_name.decode('utf-8')] = var_value + var_name = b'' + var_value = b'' + state = 'var' + return data + + def MAC(self, key, seq, msg): + mac = hmac.HMAC(key=key, digestmod=self.hash) + seqnum = num_to_bytes(seq) + mac.update(seqnum) + mac.update(msg) + return mac.digest()[:10] + b'\x00\x01' + seqnum + + def A1(self): + username = self.credentials['username'] + password = self.credentials['password'] + authzid = self.credentials['authzid'] + realm = self.credentials['realm'] + + a1 = self.hash() + a1.update(username + b':' + realm + b':' + password) + a1 = a1.digest() + a1 += b':' + self.nonce + b':' + self.cnonce + if authzid: + a1 += b':' + authzid + + return bytes(a1) + + def A2(self, prefix=b''): + a2 = prefix + b':' + self.digest_uri() + if self.qop in (b'auth-int', b'auth-conf'): + a2 += b':00000000000000000000000000000000' + return bytes(a2) + + def response(self, prefix=b''): + nc = bytes('%08x' % self.nonce_count) + + a1 = bytes(self.hash(self.A1()).hexdigest().lower()) + a2 = bytes(self.hash(self.A2(prefix)).hexdigest().lower()) + s = self.nonce + b':' + nc + b':' + self.cnonce + \ + b':' + self.qop + b':' + a2 + + return bytes(self.hash(a1 + b':' + s).hexdigest().lower()) + + def digest_uri(self): + serv_type = self.credentials['service'] + serv_name = self.credentials['service-name'] + host = self.credentials['host'] + + uri = serv_type + b'/' + host + if serv_name and host != serv_name: + uri += b'/' + serv_name + return uri + + def respond(self): + data = { + 'username': quote(self.credentials['username']), + 'authzid': quote(self.credentials['authzid']), + 'realm': quote(self.credentials['realm']), + 'nonce': quote(self.nonce), + 'cnonce': quote(self.cnonce), + 'nc': bytes('%08x' % self.nonce_count), + 'qop': self.qop, + 'digest-uri': quote(self.digest_uri()), + 'response': self.response(b'AUTHENTICATE'), + 'maxbuf': self.maxbuf + } + resp = b'' + for key, value in data.items(): + if value and value != b'""': + resp += b',' + bytes(key) + b'=' + bytes(value) + return resp[1:] + + def process(self, challenge=b''): + if not challenge: + if self.cnonce and self.nonce and self.nonce_count and self.qop: + self.nonce_count += 1 + return self.respond() + return b'' + + data = self.parse(challenge) + if 'rspauth' in data: + if data['rspauth'] != self.response(): + raise SASLMutualAuthFailed() + else: + self.nonce_count = 1 + self.cnonce = bytes('%s' % random.random())[2:] + self.qops = data.get('qop', [b'auth']) + self.qop = b'auth' + if 'nonce' in data: + self.nonce = data['nonce'] + if 'realm' in data and not self.credentials['realm']: + self.credentials['realm'] = data['realm'] + + return self.respond() + + +try: + import kerberos +except ImportError: + pass +else: + @sasl_mech(75) + class GSSAPI(Mech): + + name = 'GSSAPI' + required_credentials = set(['username', 'service-name']) + optional_credentials = set(['authzid']) + + def setup(self, name): + authzid = self.credentials['authzid'] + if not authzid: + authzid = 'xmpp@%s' % self.credentials['service-name'] + + _, self.gss = kerberos.authGSSClientInit(authzid) + self.step = 0 + + def process(self, challenge=b''): + b64_challenge = b64encode(challenge) + try: + if self.step == 0: + result = kerberos.authGSSClientStep(self.gss, b64_challenge) + if result != kerberos.AUTH_GSS_CONTINUE: + self.step = 1 + elif self.step == 1: + username = self.credentials['username'] + + kerberos.authGSSClientUnwrap(self.gss, b64_challenge) + resp = kerberos.authGSSClientResponse(self.gss) + kerberos.authGSSClientWrap(self.gss, resp, username) + + resp = kerberos.authGSSClientResponse(self.gss) + except kerberos.GSSError as e: + raise SASLCancelled('Kerberos error: %s' % e.message) + if not resp: + return b'' + else: + return b64decode(resp) |