Integrate a modified version of Dave Cridland's Suelta SASL library.

1 files changed, 273 insertions, 0 deletions

diff --git a/sleekxmpp/thirdparty/suelta/mechanisms/digest_md5.py b/sleekxmpp/thirdparty/suelta/mechanisms/digest_md5.py
new file mode 100644
index 00000000..5492c553
--- /dev/null
+++ b/sleekxmpp/thirdparty/suelta/mechanisms/digest_md5.py
@@ -0,0 +1,273 @@
+import sys
+
+import random
+
+from sleekxmpp.thirdparty.suelta.util import hash, bytes, quote
+from sleekxmpp.thirdparty.suelta.sasl import Mechanism, register_mechanism
+from sleekxmpp.thirdparty.suelta.exceptions import SASLError, SASLCancelled
+
+
+
+def parse_challenge(stuff):
+    """
+    """
+    ret = {}
+    var = b''
+    val = b''
+    in_var = True
+    in_quotes = False
+    new = False
+    escaped = False
+    for c in stuff:
+        if sys.version_info >= (3, 0):
+            c = bytes([c])
+        if in_var:
+            if c.isspace():
+                continue
+            if c == b'=':
+                in_var = False
+                new = True
+            else:
+                var += c
+        else:
+            if new:
+                if c == b'"':
+                    in_quotes = True
+                else:
+                    val += c
+                new = False
+            elif in_quotes:
+                if escaped:
+                    escaped = False
+                    val += c
+                else:
+                    if c == b'\\':
+                        escaped = True
+                    elif c == b'"':
+                        in_quotes = False
+                    else:
+                        val += c
+            else:
+                if c == b',':
+                    if var:
+                        ret[var] = val
+                    var = b''
+                    val = b''
+                    in_var = True
+                else:
+                    val += c
+    if var:
+        ret[var] = val
+    return ret
+
+
+class DIGEST_MD5(Mechanism):
+
+    """
+    """
+
+    enc_magic = 'Digest session key to client-to-server signing key magic'
+    dec_magic = 'Digest session key to server-to-client signing key magic'
+
+    def __init__(self, sasl, name):
+        """
+        """
+        super(DIGEST_MD5, self).__init__(sasl, name, 3)
+
+        self.hash = hash(name[7:])
+        if self.hash is None:
+            raise SASLCancelled(self.sasl, self)
+
+        if not self.sasl.tls_active():
+            if not self.sasl.sec_query(self, '-ENCRYPTION, DIGEST-MD5'):
+                raise SASLCancelled(self.sasl, self)
+
+        self._rspauth_okay = False
+        self._digest_uri = None
+        self._a1 = None
+        self._enc_buf = b''
+        self._enc_key = None
+        self._enc_seq = 0
+        self._max_buffer = 65536
+        self._dec_buf = b''
+        self._dec_key = None
+        self._dec_seq = 0
+        self._qops = [b'auth']
+        self._qop = b'auth'
+
+    def MAC(self, seq, msg, key):
+        """
+        """
+        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 encode(self, text):
+        """
+        """
+        self._enc_buf += text
+
+    def flush(self):
+        """
+        """
+        result = b''
+        # Leave buffer space for the MAC
+        mbuf = self._max_buffer - 10 - 2 - 4
+
+        while self._enc_buf:
+            msg = self._encbuf[:mbuf]
+            mac = self.MAC(self._enc_seq, msg, self._enc_key, self.hash)
+            self._enc_seq += 1
+            msg += mac
+            result += num_to_bytes(len(msg)) + msg
+            self._enc_buf = self._enc_buf[mbuf:]
+
+        return result
+
+    def decode(self, text):
+        """
+        """
+        self._dec_buf += text
+        result = b''
+
+        while len(self._dec_buf) > 4:
+            num = bytes_to_num(self._dec_buf)
+            if len(self._dec_buf) < (num + 4):
+                return result
+
+            mac = self._dec_buf[4:4 + num]
+            self._dec_buf = self._dec_buf[4 + num:]
+            msg = mac[:-16]
+
+            mac_conf = self.MAC(self._dec_mac, msg, self._dec_key)
+            if mac[-16:] != mac_conf:
+                self._desc_sec = None
+                return result
+
+            self._dec_seq += 1
+            result += msg
+
+        return result
+
+    def response(self):
+        """
+        """
+        vitals = ['username']
+        if not self.has_values(['key_hash']):
+            vitals.append('password')
+        self.check_values(vitals)
+
+        resp = {}
+        if 'auth-int' in self._qops:
+            self._qop = b'auth-int'
+        resp['qop'] = self._qop
+        if 'realm' in self.values:
+            resp['realm'] = quote(self.values['realm'])
+
+        resp['username'] = quote(bytes(self.values['username']))
+        resp['nonce'] = quote(self.values['nonce'])
+        if self.values['nc']:
+            self._cnonce = self.values['cnonce']
+        else:
+            self._cnonce = bytes('%s' % random.random())[2:]
+        resp['cnonce'] = quote(self._cnonce)
+        self.values['nc'] += 1
+        resp['nc'] = bytes('%08x' % self.values['nc'])
+
+        service = bytes(self.sasl.service)
+        host = bytes(self.sasl.host)
+        self._digest_uri = service + b'/' + host
+        resp['digest-uri'] = quote(self._digest_uri)
+
+        a2 = b'AUTHENTICATE:' + self._digest_uri
+        if self._qop != b'auth':
+            a2 += b':00000000000000000000000000000000'
+            resp['maxbuf'] = b'16777215'  # 2**24-1
+        resp['response'] = self.gen_hash(a2)
+        return b','.join([bytes(k) + b'=' + bytes(v) for k, v in resp.items()])
+
+    def gen_hash(self, a2):
+        """
+        """
+        if not self.has_values(['key_hash']):
+            key_hash = self.hash()
+            user = bytes(self.values['username'])
+            password = bytes(self.values['password'])
+            realm = bytes(self.values['realm'])
+            kh = user + b':' + realm + b':' + password
+            key_hash.update(kh)
+            self.values['key_hash'] = key_hash.digest()
+
+        a1 = self.hash(self.values['key_hash'])
+        a1h = b':' + self.values['nonce'] + b':' + self._cnonce
+        a1.update(a1h)
+        response = self.hash()
+        self._a1 = a1.digest()
+        rv = bytes(a1.hexdigest().lower())
+        rv += b':' + self.values['nonce']
+        rv += b':' + bytes('%08x' % self.values['nc'])
+        rv += b':' + self._cnonce
+        rv += b':' + self._qop
+        rv += b':' + bytes(self.hash(a2).hexdigest().lower())
+        response.update(rv)
+        return bytes(response.hexdigest().lower())
+
+    def mutual_auth(self, cmp_hash):
+        """
+        """
+        a2 = b':' + self._digest_uri
+        if self._qop != b'auth':
+            a2 += b':00000000000000000000000000000000'
+        if self.gen_hash(a2) == cmp_hash:
+            self._rspauth_okay = True
+
+    def prep(self):
+        """
+        """
+        if 'password' in self.values:
+            del self.values['password']
+        self.values['cnonce'] = self._cnonce
+
+    def process(self, challenge=None):
+        """
+        """
+        if challenge is None:
+            if self.has_values(['username', 'realm', 'nonce', 'key_hash',
+                                'nc', 'cnonce', 'qops']):
+                self._qops = self.values['qops']
+                return self.response()
+            else:
+                return None
+
+        d = parse_challenge(challenge)
+        if b'rspauth' in d:
+            self.mutual_auth(d[b'rspauth'])
+        else:
+            if b'realm' not in d:
+                d[b'realm'] = self.sasl.def_realm
+            for key in ['nonce', 'realm']:
+                if bytes(key) in d:
+                    self.values[key] = d[bytes(key)]
+            self.values['nc'] = 0
+            self._qops = [b'auth']
+            if b'qop' in d:
+                self._qops = [x.strip() for x in d[b'qop'].split(b',')]
+            self.values['qops'] = self._qops
+            if b'maxbuf' in d:
+                self._max_buffer = int(d[b'maxbuf'])
+            return self.response()
+
+    def okay(self):
+        """
+        """
+        if self._rspauth_okay and self._qop == b'auth-int':
+            self._enc_key = self.hash(self._a1 + self.enc_magic).digest()
+            self._dec_key = self.hash(self._a1 + self.dec_magic).digest()
+            self.encoding = True
+        return self._rspauth_okay
+
+
+register_mechanism('DIGEST-', 30, DIGEST_MD5)