273 lines
7.9 KiB
Python
273 lines
7.9 KiB
Python
import sys
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import random
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from sleekxmpp.thirdparty.suelta.util import hash, bytes, quote
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from sleekxmpp.thirdparty.suelta.sasl import Mechanism, register_mechanism
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from sleekxmpp.thirdparty.suelta.exceptions import SASLError, SASLCancelled
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def parse_challenge(stuff):
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"""
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"""
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ret = {}
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var = b''
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val = b''
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in_var = True
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in_quotes = False
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new = False
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escaped = False
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for c in stuff:
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if sys.version_info >= (3, 0):
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c = bytes([c])
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if in_var:
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if c.isspace():
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continue
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if c == b'=':
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in_var = False
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new = True
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else:
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var += c
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else:
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if new:
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if c == b'"':
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in_quotes = True
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else:
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val += c
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new = False
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elif in_quotes:
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if escaped:
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escaped = False
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val += c
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else:
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if c == b'\\':
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escaped = True
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elif c == b'"':
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in_quotes = False
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else:
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val += c
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else:
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if c == b',':
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if var:
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ret[var] = val
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var = b''
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val = b''
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in_var = True
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else:
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val += c
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if var:
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ret[var] = val
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return ret
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class DIGEST_MD5(Mechanism):
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"""
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"""
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enc_magic = 'Digest session key to client-to-server signing key magic'
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dec_magic = 'Digest session key to server-to-client signing key magic'
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def __init__(self, sasl, name):
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"""
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"""
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super(DIGEST_MD5, self).__init__(sasl, name, 3)
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self.hash = hash(name[7:])
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if self.hash is None:
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raise SASLCancelled(self.sasl, self)
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if not self.sasl.tls_active():
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if not self.sasl.sec_query(self, '-ENCRYPTION, DIGEST-MD5'):
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raise SASLCancelled(self.sasl, self)
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self._rspauth_okay = False
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self._digest_uri = None
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self._a1 = None
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self._enc_buf = b''
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self._enc_key = None
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self._enc_seq = 0
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self._max_buffer = 65536
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self._dec_buf = b''
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self._dec_key = None
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self._dec_seq = 0
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self._qops = [b'auth']
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self._qop = b'auth'
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def MAC(self, seq, msg, key):
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"""
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"""
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mac = hmac.HMAC(key=key, digestmod=self.hash)
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seqnum = num_to_bytes(seq)
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mac.update(seqnum)
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mac.update(msg)
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return mac.digest()[:10] + b'\x00\x01' + seqnum
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def encode(self, text):
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"""
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"""
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self._enc_buf += text
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def flush(self):
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"""
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"""
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result = b''
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# Leave buffer space for the MAC
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mbuf = self._max_buffer - 10 - 2 - 4
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while self._enc_buf:
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msg = self._encbuf[:mbuf]
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mac = self.MAC(self._enc_seq, msg, self._enc_key, self.hash)
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self._enc_seq += 1
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msg += mac
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result += num_to_bytes(len(msg)) + msg
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self._enc_buf = self._enc_buf[mbuf:]
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return result
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def decode(self, text):
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"""
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"""
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self._dec_buf += text
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result = b''
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while len(self._dec_buf) > 4:
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num = bytes_to_num(self._dec_buf)
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if len(self._dec_buf) < (num + 4):
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return result
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mac = self._dec_buf[4:4 + num]
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self._dec_buf = self._dec_buf[4 + num:]
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msg = mac[:-16]
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mac_conf = self.MAC(self._dec_mac, msg, self._dec_key)
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if mac[-16:] != mac_conf:
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self._desc_sec = None
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return result
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self._dec_seq += 1
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result += msg
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return result
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def response(self):
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"""
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"""
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vitals = ['username']
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if not self.has_values(['key_hash']):
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vitals.append('password')
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self.check_values(vitals)
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resp = {}
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if 'auth-int' in self._qops:
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self._qop = b'auth-int'
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resp['qop'] = self._qop
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if 'realm' in self.values:
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resp['realm'] = quote(self.values['realm'])
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resp['username'] = quote(bytes(self.values['username']))
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resp['nonce'] = quote(self.values['nonce'])
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if self.values['nc']:
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self._cnonce = self.values['cnonce']
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else:
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self._cnonce = bytes('%s' % random.random())[2:]
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resp['cnonce'] = quote(self._cnonce)
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self.values['nc'] += 1
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resp['nc'] = bytes('%08x' % self.values['nc'])
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service = bytes(self.sasl.service)
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host = bytes(self.sasl.host)
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self._digest_uri = service + b'/' + host
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resp['digest-uri'] = quote(self._digest_uri)
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a2 = b'AUTHENTICATE:' + self._digest_uri
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if self._qop != b'auth':
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a2 += b':00000000000000000000000000000000'
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resp['maxbuf'] = b'16777215' # 2**24-1
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resp['response'] = self.gen_hash(a2)
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return b','.join([bytes(k) + b'=' + bytes(v) for k, v in resp.items()])
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def gen_hash(self, a2):
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"""
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"""
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if not self.has_values(['key_hash']):
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key_hash = self.hash()
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user = bytes(self.values['username'])
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password = bytes(self.values['password'])
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realm = bytes(self.values['realm'])
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kh = user + b':' + realm + b':' + password
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key_hash.update(kh)
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self.values['key_hash'] = key_hash.digest()
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a1 = self.hash(self.values['key_hash'])
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a1h = b':' + self.values['nonce'] + b':' + self._cnonce
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a1.update(a1h)
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response = self.hash()
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self._a1 = a1.digest()
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rv = bytes(a1.hexdigest().lower())
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rv += b':' + self.values['nonce']
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rv += b':' + bytes('%08x' % self.values['nc'])
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rv += b':' + self._cnonce
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rv += b':' + self._qop
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rv += b':' + bytes(self.hash(a2).hexdigest().lower())
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response.update(rv)
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return bytes(response.hexdigest().lower())
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def mutual_auth(self, cmp_hash):
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"""
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"""
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a2 = b':' + self._digest_uri
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if self._qop != b'auth':
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a2 += b':00000000000000000000000000000000'
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if self.gen_hash(a2) == cmp_hash:
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self._rspauth_okay = True
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def prep(self):
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"""
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"""
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if 'password' in self.values:
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del self.values['password']
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self.values['cnonce'] = self._cnonce
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def process(self, challenge=None):
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"""
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"""
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if challenge is None:
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if self.has_values(['username', 'realm', 'nonce', 'key_hash',
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'nc', 'cnonce', 'qops']):
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self._qops = self.values['qops']
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return self.response()
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else:
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return None
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d = parse_challenge(challenge)
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if b'rspauth' in d:
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self.mutual_auth(d[b'rspauth'])
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else:
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if b'realm' not in d:
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d[b'realm'] = self.sasl.def_realm
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for key in ['nonce', 'realm']:
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if bytes(key) in d:
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self.values[key] = d[bytes(key)]
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self.values['nc'] = 0
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self._qops = [b'auth']
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if b'qop' in d:
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self._qops = [x.strip() for x in d[b'qop'].split(b',')]
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self.values['qops'] = self._qops
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if b'maxbuf' in d:
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self._max_buffer = int(d[b'maxbuf'])
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return self.response()
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def okay(self):
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"""
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"""
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if self._rspauth_okay and self._qop == b'auth-int':
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self._enc_key = self.hash(self._a1 + self.enc_magic).digest()
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self._dec_key = self.hash(self._a1 + self.dec_magic).digest()
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self.encoding = True
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return self._rspauth_okay
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register_mechanism('DIGEST-', 30, DIGEST_MD5)
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