Python port of ShadowsocksR
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#!/usr/bin/env python
#
# Copyright 2015-2015 breakwa11
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
from __future__ import absolute_import, division, print_function, \
with_statement
import os
import sys
import hashlib
import logging
import binascii
import struct
import base64
import time
import random
import hmac
import hashlib
import string
from shadowsocks import common
from shadowsocks.obfsplugin import plain
from shadowsocks.common import to_bytes, to_str, ord
from shadowsocks import lru_cache
def create_tls_ticket_auth_obfs(method):
return tls_ticket_auth(method)
obfs_map = {
'tls1.2_ticket_auth': (create_tls_ticket_auth_obfs,),
'tls1.2_ticket_auth_compatible': (create_tls_ticket_auth_obfs,),
}
def match_begin(str1, str2):
if len(str1) >= len(str2):
if str1[:len(str2)] == str2:
return True
return False
class obfs_auth_data(object):
def __init__(self):
self.client_data = lru_cache.LRUCache(60 * 5)
self.client_id = os.urandom(32)
self.startup_time = int(time.time() - 60 * 30) & 0xFFFFFFFF
class tls_ticket_auth(plain.plain):
def __init__(self, method):
self.method = method
self.handshake_status = 0
self.send_buffer = b''
self.recv_buffer = b''
self.client_id = b''
self.max_time_dif = 0 # time dif (second) setting
self.tls_version = b'\x03\x03'
def init_data(self):
return obfs_auth_data()
def sni(self, url):
url = common.to_bytes(url)
data = b"\x00" + struct.pack('>H', len(url)) + url
data = b"\x00\x00" + struct.pack('>H', len(data) + 2) + struct.pack('>H', len(data)) + data
return data
def pack_auth_data(self, client_id):
utc_time = int(time.time()) & 0xFFFFFFFF
data = struct.pack('>I', utc_time) + os.urandom(18)
data += hmac.new(self.server_info.key + client_id, data, hashlib.sha1).digest()[:10]
return data
def client_encode(self, buf):
if self.handshake_status == -1:
return buf
if self.handshake_status == 8:
return b"\x17" + self.tls_version + struct.pack('>H', len(buf)) + buf
self.send_buffer += b"\x17" + self.tls_version + struct.pack('>H', len(buf)) + buf
if self.handshake_status == 0:
self.handshake_status = 1
data = self.tls_version + self.pack_auth_data(self.server_info.data.client_id) + b"\x20" + self.server_info.data.client_id + binascii.unhexlify(b"001cc02bc02fcca9cca8cc14cc13c00ac014c009c013009c0035002f000a" + b"0100")
ext = binascii.unhexlify(b"ff01000100")
host = self.server_info.obfs_param or self.server_info.host
if host and host[-1] in string.digits:
host = ''
hosts = host.split(',')
host = random.choice(hosts)
ext += self.sni(host)
ext += b"\x00\x17\x00\x00"
ext += b"\x00\x23\x00\xd0" + os.urandom(208) # ticket
ext += binascii.unhexlify(b"000d001600140601060305010503040104030301030302010203")
ext += binascii.unhexlify(b"000500050100000000")
ext += binascii.unhexlify(b"00120000")
ext += binascii.unhexlify(b"75500000")
ext += binascii.unhexlify(b"000b00020100")
ext += binascii.unhexlify(b"000a0006000400170018")
data += struct.pack('>H', len(ext)) + ext
data = b"\x01\x00" + struct.pack('>H', len(data)) + data
data = b"\x16\x03\x01" + struct.pack('>H', len(data)) + data
return data
elif self.handshake_status == 1 and len(buf) == 0:
data = b"\x14" + self.tls_version + b"\x00\x01\x01" #ChangeCipherSpec
data += b"\x16" + self.tls_version + b"\x00\x20" + os.urandom(22) #Finished
data += hmac.new(self.server_info.key + self.server_info.data.client_id, data, hashlib.sha1).digest()[:10]
ret = data + self.send_buffer
self.send_buffer = b''
self.handshake_status = 8
return ret
return b''
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')
return (b'', True)
def server_encode(self, buf):
if self.handshake_status == -1:
return buf
if self.handshake_status == 8:
ret = b''
while len(buf) > 8192:
ret += b"\x17" + self.tls_version + struct.pack('>H', 8192) + buf[:8192]
buf = buf[8192:]
if len(buf) > 0:
ret += b"\x17" + self.tls_version + struct.pack('>H', len(buf)) + buf
return ret
self.handshake_status = 3
data = self.tls_version + self.pack_auth_data(self.client_id) + b"\x20" + self.client_id + binascii.unhexlify(b"c02f000005ff01000100")
data = b"\x02\x00" + struct.pack('>H', len(data)) + data #server hello
data = b"\x16\x03\x03" + struct.pack('>H', len(data)) + data
data += b"\x14" + self.tls_version + b"\x00\x01\x01" #ChangeCipherSpec
data += b"\x16" + self.tls_version + b"\x00\x20" + os.urandom(22) #Finished
data += hmac.new(self.server_info.key + self.client_id, data, hashlib.sha1).digest()[:10]
return data
def decode_error_return(self, buf):
self.handshake_status = -1
if self.method == 'tls1.2_ticket_auth':
return (b'E'*64, False, False)
return (buf, True, False)
def server_decode(self, buf):
if self.handshake_status == -1:
return (buf, True, 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
ret += self.recv_buffer[5:size+5]
self.recv_buffer = self.recv_buffer[size+5:]
return (ret, True, False)
if self.handshake_status == 3:
verify = buf
verify_len = 43 - 10
if len(buf) < 43:
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\x20"): #Finished
raise Exception('server_decode data error')
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')
if len(buf) < 37:
raise Exception('server_decode data error')
self.recv_buffer = buf[37:]
self.handshake_status = 8
return self.server_decode(b'')
#raise Exception("handshake data = %s" % (binascii.hexlify(buf)))
self.handshake_status = 2
ogn_buf = buf
if not match_begin(buf, b'\x16\x03\x01'):
return self.decode_error_return(ogn_buf)
buf = buf[3:]
if struct.unpack('>H', buf[:2])[0] != len(buf) - 2:
logging.info("tls_auth wrong tls head size")
return self.decode_error_return(ogn_buf)
buf = buf[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
# (buffer_to_recv, is_need_decrypt, is_need_to_encode_and_send_back)
return (b'', False, True)