From 5ab77c745270d7d5c016c1dc7ef2a82533a4b16e Mon Sep 17 00:00:00 2001
From: Florent Le Coz <louiz@louiz.org>
Date: Thu, 17 Jul 2014 14:19:04 +0200
Subject: Rename to slixmpp

---
 slixmpp/util/sasl/mechanisms.py | 551 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 551 insertions(+)
 create mode 100644 slixmpp/util/sasl/mechanisms.py

(limited to 'slixmpp/util/sasl/mechanisms.py')

diff --git a/slixmpp/util/sasl/mechanisms.py b/slixmpp/util/sasl/mechanisms.py
new file mode 100644
index 00000000..a05f17ae
--- /dev/null
+++ b/slixmpp/util/sasl/mechanisms.py
@@ -0,0 +1,551 @@
+# -*- coding: utf-8 -*-
+"""
+    slixmpp.util.sasl.mechanisms
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+    A collection of supported SASL mechanisms.
+
+    This module was originally based on Dave Cridland's Suelta library.
+
+    Part of Slixmpp: The Slick XMPP Library
+
+    :copryight: (c) 2004-2013 David Alan Cridland
+    :copyright: (c) 2013 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 slixmpp.util import bytes, hash, XOR, quote, num_to_bytes
+from slixmpp.util.sasl.client import sasl_mech, Mech, \
+                                       SASLCancelled, SASLFailed, \
+                                       SASLMutualAuthFailed
+
+
+@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(31)
+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.decode("utf-8"), v.decode("utf-8")) 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(10)
+class X_OAUTH2(Mech):
+
+    name = 'X-OAUTH2'
+    required_credentials = set(['username', 'access_token'])
+
+    def process(self, challenge=b''):
+        return b'\x00' + self.credentials['username'] + \
+               b'\x00' + 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 = b''
+        if self.use_channel_binding:
+            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,
+            'charset': 'utf-8'
+        }
+        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 None
+
+        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 not challenge:
+                    kerberos.authGSSClientClean(self.gss)
+                    return b''
+                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)
+            if not resp:
+                return b''
+            else:
+                return b64decode(resp)
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