def get_head_size(self, buf, def_value):
if len(buf) < 2:
return def_value
head_type = ord(buf[0]) & 0x7
if head_type == 1:
return 7
if head_type == 4:
return 19
if head_type == 3:
return 4 + ord(buf[1])
return def_value
def client_decode(self, buf):
if self.handshake_status == -1:
return (buf, False)
if self.handshake_status == 8:
ret = b''
self.recv_buffer += buf
while len(self.recv_buffer) > 5:
if ord(self.recv_buffer[0]) != 0x17:
logging.info("data = %s" % (binascii.hexlify(self.recv_buffer)))
raise Exception('server_decode appdata error')
size = struct.unpack('>H', self.recv_buffer[3:5])[0]
if len(self.recv_buffer) < size + 5:
break
buf = self.recv_buffer[5:size+5]
ret += buf
self.recv_buffer = self.recv_buffer[size+5:]
return (ret, False)
if len(buf) < 11 + 32 + 1 + 32:
raise Exception('client_decode data error')
verify = buf[11:33]
if hmac.new(self.server_info.key + self.server_info.data.client_id, verify, hashlib.sha1).digest()[:10] != buf[33:43]:
raise Exception('client_decode data error')
if hmac.new(self.server_info.key + self.server_info.data.client_id, buf[:-10], hashlib.sha1).digest()[:10] != buf[-10:]:
raise Exception('client_decode data error')
return (b'', True)
def parse_name(data, offset):
p = offset
labels = []
l = common.ord(data[p])
while l > 0:
if (l & (128 + 64)) == (128 + 64):
# pointer
pointer = struct.unpack('!H', data[p:p + 2])[0]
pointer &= 0x3FFF
r = parse_name(data, pointer)
labels.append(r[1])
p += 2
# pointer is the end
return p - offset, b'.'.join(labels)
else:
labels.append(data[p + 1:p + 1 + l])
p += 1 + l
l = common.ord(data[p])
return p - offset + 1, b'.'.join(labels)
def rnd_data_len(self, buf_size, full_buf_size):
if full_buf_size >= self.server_info.buffer_size:
return 0
tcp_mss = self.server_info.tcp_mss
rev_len = tcp_mss - buf_size - 9
if rev_len == 0:
return 0
if rev_len < 0:
if rev_len > -tcp_mss:
return self.trapezoid_random_int(rev_len + tcp_mss, -0.3)
return common.ord(os.urandom(1)[0]) % 32
if buf_size > 900:
return struct.unpack('>H', os.urandom(2))[0] % rev_len
return self.trapezoid_random_int(rev_len, -0.3)
def rnd_data(self, buf_size):
if buf_size > 1200:
return b'\x01'
if buf_size > 400:
rnd_data = os.urandom(common.ord(os.urandom(1)[0]) % 256)
else:
rnd_data = os.urandom(struct.unpack('>H', os.urandom(2))[0] % 512)
if len(rnd_data) < 128:
return common.chr(len(rnd_data) + 1) + rnd_data
else:
return common.chr(255) + struct.pack('>H',
len(rnd_data) + 3) + rnd_data
def client_encode(self, buf):
if self.raw_trans_sent:
return buf
self.send_buffer += buf
if not self.has_sent_header:
self.has_sent_header = True
data = os.urandom(common.ord(os.urandom(1)[0]) % 96 + 4)
crc = (0xffffffff - binascii.crc32(data)) & 0xffffffff
return data + struct.pack('<I', crc)
if self.raw_trans_recv:
ret = self.send_buffer
self.send_buffer = b''
self.raw_trans_sent = True
return ret
return b''
def client_post_decrypt(self, buf):
if self.raw_trans:
return buf
self.recv_buf += buf
out_buf = b''
while len(self.recv_buf) > 4:
mac_key = self.user_key + struct.pack('<I', self.recv_id)
mac = hmac.new(mac_key, self.recv_buf[:2],
self.hashfunc).digest()[:2]
if mac != self.recv_buf[2:4]:
raise Exception('client_post_decrypt data uncorrect mac')
length = struct.unpack('<H', self.recv_buf[:2])[0]
if length >= 8192 or length < 7:
self.raw_trans = True
self.recv_buf = b''
raise Exception('client_post_decrypt data error')
if length > len(self.recv_buf):
break
if hmac.new(mac_key, self.recv_buf[:length - 4],
self.hashfunc).digest()[:4] != self.recv_buf[length -
4:length]:
self.raw_trans = True
self.recv_buf = b''
raise Exception('client_post_decrypt data uncorrect checksum')
self.recv_id = (self.recv_id + 1) & 0xFFFFFFFF
pos = common.ord(self.recv_buf[4])
if pos < 255:
pos += 4
else:
pos = struct.unpack('<H', self.recv_buf[5:7])[0] + 4
out_buf += self.recv_buf[pos:length - 4]
self.recv_buf = self.recv_buf[length:]
return out_buf
def client_post_decrypt(self, buf):
if self.raw_trans:
return buf
self.recv_buf += buf
out_buf = b''
while len(self.recv_buf) > 4:
crc = struct.pack('<H', binascii.crc32(self.recv_buf[:2]) & 0xFFFF)
if crc != self.recv_buf[2:4]:
raise Exception('client_post_decrypt data uncorrect crc')
length = struct.unpack('>H', self.recv_buf[:2])[0]
if length >= 8192 or length < 7:
self.raw_trans = True
self.recv_buf = b''
raise Exception('client_post_decrypt data error')
if length > len(self.recv_buf):
break
if struct.pack(
'<I',
zlib.adler32(self.recv_buf[:length - 4])
& 0xFFFFFFFF) != self.recv_buf[length - 4:length]:
self.raw_trans = True
self.recv_buf = b''
raise Exception('client_post_decrypt data uncorrect checksum')
pos = common.ord(self.recv_buf[4])
if pos < 255:
pos += 4
else:
pos = struct.unpack('>H', self.recv_buf[5:7])[0] + 4
out_buf += self.recv_buf[pos:length - 4]
self.recv_buf = self.recv_buf[length:]
if out_buf:
self.decrypt_packet_num += 1
return out_buf
def server_decode(self, buf):
if self.handshake_status == -1:
return (buf, True, False)
if (self.handshake_status & 4) == 4:
ret = b''
self.recv_buffer += buf
while len(self.recv_buffer) > 5:
if ord(self.recv_buffer[0]) != 0x17 or ord(self.recv_buffer[1]) != 0x3 or ord(self.recv_buffer[2]) != 0x3:
logging.info("data = %s" % (binascii.hexlify(self.recv_buffer)))
raise Exception('server_decode appdata error')
size = struct.unpack('>H', self.recv_buffer[3:5])[0]
if len(self.recv_buffer) < size + 5:
break
ret += self.recv_buffer[5:size+5]
self.recv_buffer = self.recv_buffer[size+5:]
return (ret, True, False)
if (self.handshake_status & 1) == 1:
self.recv_buffer += buf
buf = self.recv_buffer
verify = buf
if len(buf) < 11:
raise Exception('server_decode data error')
if not match_begin(buf, b"\x14" + self.tls_version + b"\x00\x01\x01"): #ChangeCipherSpec
raise Exception('server_decode data error')
buf = buf[6:]
if not match_begin(buf, b"\x16" + self.tls_version + b"\x00"): #Finished
raise Exception('server_decode data error')
verify_len = struct.unpack('>H', buf[3:5])[0] + 1 # 11 - 10
if len(verify) < verify_len + 10:
return (b'', False, False)
if hmac.new(self.server_info.key + self.client_id, verify[:verify_len], hashlib.sha1).digest()[:10] != verify[verify_len:verify_len+10]:
raise Exception('server_decode data error')
self.recv_buffer = verify[verify_len + 10:]
status = self.handshake_status
self.handshake_status |= 4
ret = self.server_decode(b'')
return ret;
#raise Exception("handshake data = %s" % (binascii.hexlify(buf)))
self.recv_buffer += buf
buf = self.recv_buffer
ogn_buf = buf
if len(buf) < 3:
return (b'', False, False)
if not match_begin(buf, b'\x16\x03\x01'):
return self.decode_error_return(ogn_buf)
buf = buf[3:]
header_len = struct.unpack('>H', buf[:2])[0]
if header_len > len(buf) - 2:
return (b'', False, False)
self.recv_buffer = self.recv_buffer[header_len + 5:]
self.handshake_status = 1
buf = buf[2:header_len + 2]
if not match_begin(buf, b'\x01\x00'): #client hello
logging.info("tls_auth not client hello message")
return self.decode_error_return(ogn_buf)
buf = buf[2:]
if struct.unpack('>H', buf[:2])[0] != len(buf) - 2:
logging.info("tls_auth wrong message size")
return self.decode_error_return(ogn_buf)
buf = buf[2:]
if not match_begin(buf, self.tls_version):
logging.info("tls_auth wrong tls version")
return self.decode_error_return(ogn_buf)
buf = buf[2:]
verifyid = buf[:32]
buf = buf[32:]
sessionid_len = ord(buf[0])
if sessionid_len < 32:
logging.info("tls_auth wrong sessionid_len")
return self.decode_error_return(ogn_buf)
sessionid = buf[1:sessionid_len + 1]
buf = buf[sessionid_len+1:]
self.client_id = sessionid
sha1 = hmac.new(self.server_info.key + sessionid, verifyid[:22], hashlib.sha1).digest()[:10]
utc_time = struct.unpack('>I', verifyid[:4])[0]
time_dif = common.int32((int(time.time()) & 0xffffffff) - utc_time)
if self.server_info.obfs_param:
try:
self.max_time_dif = int(self.server_info.obfs_param)
except:
pass
if self.max_time_dif > 0 and (time_dif < -self.max_time_dif or time_dif > self.max_time_dif \
or common.int32(utc_time - self.server_info.data.startup_time) < -self.max_time_dif / 2):
logging.info("tls_auth wrong time")
return self.decode_error_return(ogn_buf)
if sha1 != verifyid[22:]:
logging.info("tls_auth wrong sha1")
return self.decode_error_return(ogn_buf)
if self.server_info.data.client_data.get(verifyid[:22]):
logging.info("replay attack detect, id = %s" % (binascii.hexlify(verifyid)))
return self.decode_error_return(ogn_buf)
self.server_info.data.client_data.sweep()
self.server_info.data.client_data[verifyid[:22]] = sessionid
if len(self.recv_buffer) >= 11:
ret = self.server_decode(b'')
return (ret[0], True, True)
# (buffer_to_recv, is_need_decrypt, is_need_to_encode_and_send_back)
return (b'', False, True)
def _handle_server(self):
server = self._server_socket
data, r_addr = server.recvfrom(BUF_SIZE)
ogn_data = data
if not data:
logging.debug('UDP handle_server: data is empty')
if self._stat_callback:
self._stat_callback(self._listen_port, len(data))
uid = None
if self._is_local:
frag = common.ord(data[2])
if frag != 0:
logging.warn('drop a message since frag is not 0')
return
else:
data = data[3:]
else:
ref_iv = [0]
data = encrypt.encrypt_all_iv(self._protocol.obfs.server_info.key,
self._method, 0, data, ref_iv)
# decrypt data
if not data:
logging.debug('UDP handle_server: data is empty after decrypt')
return
self._protocol.obfs.server_info.recv_iv = ref_iv[0]
data, uid = self._protocol.server_udp_post_decrypt(data)
#logging.info("UDP data %s" % (binascii.hexlify(data),))
if not self._is_local:
data = pre_parse_header(data)
if data is None:
return
try:
header_result = parse_header(data)
except:
self._handel_protocol_error(r_addr, ogn_data)
return
if header_result is None:
self._handel_protocol_error(r_addr, ogn_data)
return
connecttype, addrtype, dest_addr, dest_port, header_length = header_result
if self._is_local:
addrtype = 3
server_addr, server_port = self._get_a_server()
else:
server_addr, server_port = dest_addr, dest_port
if (addrtype & 7) == 3:
af = common.is_ip(server_addr)
if af == False:
handler = common.UDPAsyncDNSHandler(
(data, r_addr, uid, header_length))
handler.resolve(self._dns_resolver, (server_addr, server_port),
self._handle_server_dns_resolved)
else:
self._handle_server_dns_resolved(
"", (server_addr, server_port), server_addr,
(data, r_addr, uid, header_length))
else:
self._handle_server_dns_resolved(
"", (server_addr, server_port), server_addr,
(data, r_addr, uid, header_length))
def server_post_decrypt(self, buf):
if self.raw_trans:
return (buf, False)
self.recv_buf += buf
out_buf = b''
sendback = False
if not self.has_recv_header:
if len(self.recv_buf) >= 7 or len(self.recv_buf) in [2, 3]:
recv_len = min(len(self.recv_buf), 7)
mac_key = self.server_info.recv_iv + self.server_info.key
sha1data = hmac.new(mac_key, self.recv_buf[:1],
self.hashfunc).digest()[:recv_len - 1]
if sha1data != self.recv_buf[1:recv_len]:
return self.not_match_return(self.recv_buf)
if len(self.recv_buf) < 31:
return (b'', False)
sha1data = hmac.new(mac_key, self.recv_buf[7:27],
self.hashfunc).digest()[:4]
if sha1data != self.recv_buf[27:31]:
logging.error(
'%s data uncorrect auth HMAC-SHA1 from %s:%d, data %s' %
(self.no_compatible_method, self.server_info.client,
self.server_info.client_port,
binascii.hexlify(self.recv_buf)))
if len(self.recv_buf) < 31 + self.extra_wait_size:
return (b'', False)
return self.not_match_return(self.recv_buf)
uid = self.recv_buf[7:11]
if uid in self.server_info.users:
self.user_id = uid
self.user_key = self.hashfunc(
self.server_info.users[uid]).digest()
self.server_info.update_user_func(uid)
else:
if not self.server_info.users:
self.user_key = self.server_info.key
else:
self.user_key = self.server_info.recv_iv
encryptor = encrypt.Encryptor(
to_bytes(base64.b64encode(self.user_key)) + self.salt,
'aes-128-cbc')
head = encryptor.decrypt(
b'\x00' * 16 + self.recv_buf[11:27] +
b'\x00') # need an extra byte or recv empty
length = struct.unpack('<H', head[12:14])[0]
if len(self.recv_buf) < length:
return (b'', False)
utc_time = struct.unpack('<I', head[:4])[0]
client_id = struct.unpack('<I', head[4:8])[0]
connection_id = struct.unpack('<I', head[8:12])[0]
rnd_len = struct.unpack('<H', head[14:16])[0]
if hmac.new(self.user_key, self.recv_buf[:length - 4],
self.hashfunc).digest()[:4] != self.recv_buf[length -
4:length]:
logging.info('%s: checksum error, data %s' %
(self.no_compatible_method,
binascii.hexlify(self.recv_buf[:length])))
return self.not_match_return(self.recv_buf)
time_dif = common.int32(utc_time - (int(time.time()) & 0xffffffff))
if time_dif < -self.max_time_dif or time_dif > self.max_time_dif:
logging.info('%s: wrong timestamp, time_dif %d, data %s' %
(self.no_compatible_method, time_dif,
binascii.hexlify(head)))
return self.not_match_return(self.recv_buf)
elif self.server_info.data.insert(self.user_id, client_id,
connection_id):
self.has_recv_header = True
out_buf = self.recv_buf[31 + rnd_len:length - 4]
self.client_id = client_id
self.connection_id = connection_id
else:
logging.info(
'%s: auth fail, data %s' %
(self.no_compatible_method, binascii.hexlify(out_buf)))
return self.not_match_return(self.recv_buf)
self.recv_buf = self.recv_buf[length:]
self.has_recv_header = True
sendback = True
while len(self.recv_buf) > 4:
mac_key = self.user_key + struct.pack('<I', self.recv_id)
mac = hmac.new(mac_key, self.recv_buf[:2],
self.hashfunc).digest()[:2]
if mac != self.recv_buf[2:4]:
self.raw_trans = True
logging.info(self.no_compatible_method + ': wrong crc')
if self.recv_id == 0:
logging.info(self.no_compatible_method + ': wrong crc')
return (b'E' * 2048, False)
else:
raise Exception('server_post_decrype data error')
length = struct.unpack('<H', self.recv_buf[:2])[0]
if length >= 8192 or length < 7:
self.raw_trans = True
self.recv_buf = b''
if self.recv_id == 0:
logging.info(self.no_compatible_method + ': over size')
return (b'E' * 2048, False)
else:
raise Exception('server_post_decrype data error')
if length > len(self.recv_buf):
break
if hmac.new(mac_key, self.recv_buf[:length - 4],
self.hashfunc).digest()[:4] != self.recv_buf[length -
4:length]:
logging.info('%s: checksum error, data %s' %
(self.no_compatible_method,
binascii.hexlify(self.recv_buf[:length])))
self.raw_trans = True
self.recv_buf = b''
if self.recv_id == 0:
return (b'E' * 2048, False)
else:
raise Exception(
'server_post_decrype data uncorrect checksum')
self.recv_id = (self.recv_id + 1) & 0xFFFFFFFF
pos = common.ord(self.recv_buf[4])
if pos < 255:
pos += 4
else:
pos = struct.unpack('<H', self.recv_buf[5:7])[0] + 4
out_buf += self.recv_buf[pos:length - 4]
self.recv_buf = self.recv_buf[length:]
if pos == length - 4:
sendback = True
if out_buf:
self.server_info.data.update(self.user_id, self.client_id,
self.connection_id)
return (out_buf, sendback)
def server_post_decrypt(self, buf):
if self.raw_trans:
return (buf, False)
self.recv_buf += buf
out_buf = b''
sendback = False
if not self.has_recv_header:
if len(self.recv_buf) <= 6:
return (b'', False)
crc = struct.pack(
'<I',
binascii.crc32(self.recv_buf[:2] + self.salt +
self.server_info.key) & 0xFFFFFFFF)
if crc != self.recv_buf[2:6]:
return self.not_match_return(self.recv_buf)
length = struct.unpack('>H', self.recv_buf[:2])[0]
if length > len(self.recv_buf):
return (b'', False)
sha1data = hmac.new(
self.server_info.recv_iv + self.server_info.key,
self.recv_buf[:length - 10], hashlib.sha1).digest()[:10]
if sha1data != self.recv_buf[length - 10:length]:
logging.error('auth_sha1_v4 data uncorrect auth HMAC-SHA1')
return self.not_match_return(self.recv_buf)
pos = common.ord(self.recv_buf[6])
if pos < 255:
pos += 6
else:
pos = struct.unpack('>H', self.recv_buf[7:9])[0] + 6
out_buf = self.recv_buf[pos:length - 10]
if len(out_buf) < 12:
logging.info('auth_sha1_v4: too short, data %s' %
(binascii.hexlify(self.recv_buf), ))
return self.not_match_return(self.recv_buf)
utc_time = struct.unpack('<I', out_buf[:4])[0]
client_id = struct.unpack('<I', out_buf[4:8])[0]
connection_id = struct.unpack('<I', out_buf[8:12])[0]
time_dif = common.int32(utc_time - (int(time.time()) & 0xffffffff))
if time_dif < -self.max_time_dif or time_dif > self.max_time_dif:
logging.info(
'auth_sha1_v4: wrong timestamp, time_dif %d, data %s' % (
time_dif,
binascii.hexlify(out_buf),
))
return self.not_match_return(self.recv_buf)
elif self.server_info.data.insert(client_id, connection_id):
self.has_recv_header = True
out_buf = out_buf[12:]
self.client_id = client_id
self.connection_id = connection_id
else:
logging.info('auth_sha1_v4: auth fail, data %s' %
(binascii.hexlify(out_buf), ))
return self.not_match_return(self.recv_buf)
self.recv_buf = self.recv_buf[length:]
self.has_recv_header = True
sendback = True
while len(self.recv_buf) > 4:
crc = struct.pack('<H', binascii.crc32(self.recv_buf[:2]) & 0xFFFF)
if crc != self.recv_buf[2:4]:
self.raw_trans = True
logging.info('auth_sha1_v4: wrong crc')
if self.decrypt_packet_num == 0:
logging.info('auth_sha1_v4: wrong crc')
return (b'E' * 2048, False)
else:
raise Exception('server_post_decrype data error')
length = struct.unpack('>H', self.recv_buf[:2])[0]
if length >= 8192 or length < 7:
self.raw_trans = True
self.recv_buf = b''
if self.decrypt_packet_num == 0:
logging.info('auth_sha1_v4: over size')
return (b'E' * 2048, False)
else:
raise Exception('server_post_decrype data error')
if length > len(self.recv_buf):
break
if struct.pack(
'<I',
zlib.adler32(self.recv_buf[:length - 4])
& 0xFFFFFFFF) != self.recv_buf[length - 4:length]:
logging.info('auth_sha1_v4: checksum error, data %s' %
(binascii.hexlify(self.recv_buf[:length]), ))
self.raw_trans = True
self.recv_buf = b''
if self.decrypt_packet_num == 0:
return (b'E' * 2048, False)
else:
raise Exception(
'server_post_decrype data uncorrect checksum')
pos = common.ord(self.recv_buf[4])
if pos < 255:
pos += 4
else:
pos = struct.unpack('>H', self.recv_buf[5:7])[0] + 4
out_buf += self.recv_buf[pos:length - 4]
self.recv_buf = self.recv_buf[length:]
if pos == length - 4:
sendback = True
if out_buf:
self.server_info.data.update(self.client_id, self.connection_id)
self.decrypt_packet_num += 1
return (out_buf, sendback)
def server_encode(self, buf):
if self.has_sent_header:
return buf
self.has_sent_header = True
return os.urandom(common.ord(os.urandom(1)[0]) % 96 + 4)