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import struct
import array
import ipaddress
from mitmproxy.net import check
from mitmproxy.coretypes import bidi
class SocksError(Exception):
def __init__(self, code, message):
super().__init__(message)
self.code = code
VERSION = bidi.BiDi(
SOCKS4=0x04,
SOCKS5=0x05
)
CMD = bidi.BiDi(
CONNECT=0x01,
BIND=0x02,
UDP_ASSOCIATE=0x03
)
ATYP = bidi.BiDi(
IPV4_ADDRESS=0x01,
DOMAINNAME=0x03,
IPV6_ADDRESS=0x04
)
REP = bidi.BiDi(
SUCCEEDED=0x00,
GENERAL_SOCKS_SERVER_FAILURE=0x01,
CONNECTION_NOT_ALLOWED_BY_RULESET=0x02,
NETWORK_UNREACHABLE=0x03,
HOST_UNREACHABLE=0x04,
CONNECTION_REFUSED=0x05,
TTL_EXPIRED=0x06,
COMMAND_NOT_SUPPORTED=0x07,
ADDRESS_TYPE_NOT_SUPPORTED=0x08,
)
METHOD = bidi.BiDi(
NO_AUTHENTICATION_REQUIRED=0x00,
GSSAPI=0x01,
USERNAME_PASSWORD=0x02,
NO_ACCEPTABLE_METHODS=0xFF
)
USERNAME_PASSWORD_VERSION = bidi.BiDi(
DEFAULT=0x01
)
class ClientGreeting:
__slots__ = ("ver", "methods")
def __init__(self, ver, methods):
self.ver = ver
self.methods = array.array("B")
self.methods.extend(methods)
def assert_socks5(self):
if self.ver != VERSION.SOCKS5:
if self.ver == ord("G") and len(self.methods) == ord("E"):
guess = "Probably not a SOCKS request but a regular HTTP request. "
else:
guess = ""
raise SocksError(
REP.GENERAL_SOCKS_SERVER_FAILURE,
guess + "Invalid SOCKS version. Expected 0x05, got 0x%x" % self.ver
)
@classmethod
def from_file(cls, f, fail_early=False):
"""
:param fail_early: If true, a SocksError will be raised if the first byte does not indicate socks5.
"""
ver, nmethods = struct.unpack("!BB", f.safe_read(2))
client_greeting = cls(ver, [])
if fail_early:
client_greeting.assert_socks5()
client_greeting.methods.frombytes(f.safe_read(nmethods))
return client_greeting
def to_file(self, f):
f.write(struct.pack("!BB", self.ver, len(self.methods)))
f.write(self.methods.tobytes())
class ServerGreeting:
__slots__ = ("ver", "method")
def __init__(self, ver, method):
self.ver = ver
self.method = method
def assert_socks5(self):
if self.ver != VERSION.SOCKS5:
if self.ver == ord("H") and self.method == ord("T"):
guess = "Probably not a SOCKS request but a regular HTTP response. "
else:
guess = ""
raise SocksError(
REP.GENERAL_SOCKS_SERVER_FAILURE,
guess + "Invalid SOCKS version. Expected 0x05, got 0x%x" % self.ver
)
@classmethod
def from_file(cls, f):
ver, method = struct.unpack("!BB", f.safe_read(2))
return cls(ver, method)
def to_file(self, f):
f.write(struct.pack("!BB", self.ver, self.method))
class UsernamePasswordAuth:
__slots__ = ("ver", "username", "password")
def __init__(self, ver, username, password):
self.ver = ver
self.username = username
self.password = password
def assert_authver1(self):
if self.ver != USERNAME_PASSWORD_VERSION.DEFAULT:
raise SocksError(
0,
"Invalid auth version. Expected 0x01, got 0x%x" % self.ver
)
@classmethod
def from_file(cls, f):
ver, ulen = struct.unpack("!BB", f.safe_read(2))
username = f.safe_read(ulen)
plen, = struct.unpack("!B", f.safe_read(1))
password = f.safe_read(plen)
return cls(ver, username.decode(), password.decode())
def to_file(self, f):
f.write(struct.pack("!BB", self.ver, len(self.username)))
f.write(self.username.encode())
f.write(struct.pack("!B", len(self.password)))
f.write(self.password.encode())
class UsernamePasswordAuthResponse:
__slots__ = ("ver", "status")
def __init__(self, ver, status):
self.ver = ver
self.status = status
def assert_authver1(self):
if self.ver != USERNAME_PASSWORD_VERSION.DEFAULT:
raise SocksError(
0,
"Invalid auth version. Expected 0x01, got 0x%x" % self.ver
)
@classmethod
def from_file(cls, f):
ver, status = struct.unpack("!BB", f.safe_read(2))
return cls(ver, status)
def to_file(self, f):
f.write(struct.pack("!BB", self.ver, self.status))
class Message:
__slots__ = ("ver", "msg", "atyp", "addr")
def __init__(self, ver, msg, atyp, addr):
self.ver = ver
self.msg = msg
self.atyp = atyp
self.addr = addr
def assert_socks5(self):
if self.ver != VERSION.SOCKS5:
raise SocksError(
REP.GENERAL_SOCKS_SERVER_FAILURE,
"Invalid SOCKS version. Expected 0x05, got 0x%x" % self.ver
)
@classmethod
def from_file(cls, f):
ver, msg, rsv, atyp = struct.unpack("!BBBB", f.safe_read(4))
if rsv != 0x00:
raise SocksError(
REP.GENERAL_SOCKS_SERVER_FAILURE,
"Socks Request: Invalid reserved byte: %s" % rsv
)
if atyp == ATYP.IPV4_ADDRESS:
# We use tnoa here as ntop is not commonly available on Windows.
host = ipaddress.IPv4Address(f.safe_read(4)).compressed
elif atyp == ATYP.IPV6_ADDRESS:
host = ipaddress.IPv6Address(f.safe_read(16)).compressed
elif atyp == ATYP.DOMAINNAME:
length, = struct.unpack("!B", f.safe_read(1))
host = f.safe_read(length)
if not check.is_valid_host(host):
raise SocksError(REP.GENERAL_SOCKS_SERVER_FAILURE, "Invalid hostname: %s" % host)
host = host.decode("idna")
else:
raise SocksError(REP.ADDRESS_TYPE_NOT_SUPPORTED,
"Socks Request: Unknown ATYP: %s" % atyp)
port, = struct.unpack("!H", f.safe_read(2))
addr = (host, port)
return cls(ver, msg, atyp, addr)
def to_file(self, f):
f.write(struct.pack("!BBBB", self.ver, self.msg, 0x00, self.atyp))
if self.atyp == ATYP.IPV4_ADDRESS:
f.write(ipaddress.IPv4Address(self.addr[0]).packed)
elif self.atyp == ATYP.IPV6_ADDRESS:
f.write(ipaddress.IPv6Address(self.addr[0]).packed)
elif self.atyp == ATYP.DOMAINNAME:
f.write(struct.pack("!B", len(self.addr[0])))
f.write(self.addr[0].encode("idna"))
else:
raise SocksError(
REP.ADDRESS_TYPE_NOT_SUPPORTED,
"Unknown ATYP: %s" % self.atyp
)
f.write(struct.pack("!H", self.addr[1]))
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