###############################################################################
#
# The MIT License (MIT)
#
# Copyright (c) typedef int GmbH
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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# THE SOFTWARE.
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from autobahn.util import public
from autobahn.wamp.interfaces import IPayloadCodec
from autobahn.wamp.serializer import _dumps as _json_dumps
from autobahn.wamp.serializer import _loads as _json_loads
from autobahn.wamp.types import EncodedPayload
__all__ = ["HAS_CRYPTOBOX", "EncodedPayload"]
try:
# try to import everything we need for WAMP-cryptobox
from nacl.encoding import Base64Encoder, HexEncoder, RawEncoder
from nacl.public import Box, PrivateKey, PublicKey
from nacl.utils import random
from pytrie import StringTrie
except ImportError:
else:
HAS_CRYPTOBOX = True
__all__.extend(["Key", "KeyRing"])
if HAS_CRYPTOBOX:
@public
class Key(object):
"""
Holds originator and responder keys for an URI.
The originator is either a caller or a publisher. The responder is either a callee or subscriber.
"""
def __init__(
self,
originator_priv=None,
originator_pub=None,
responder_priv=None,
responder_pub=None,
):
# the originator private and public keys, as available
if originator_priv:
self.originator_priv = PrivateKey(
originator_priv, encoder=Base64Encoder
)
else:
self.originator_priv = None
if self.originator_priv:
self.originator_pub = self.originator_priv.public_key
assert originator_pub is None or originator_pub == self.originator_pub
else:
self.originator_pub = PublicKey(originator_pub, encoder=Base64Encoder)
# the responder private and public keys, as available
if responder_priv:
self.responder_priv = PrivateKey(responder_priv, encoder=Base64Encoder)
else:
self.responder_priv = None
if self.responder_priv:
self.responder_pub = self.responder_priv.public_key
assert responder_pub is None or responder_pub == self.responder_pub
else:
self.responder_pub = PublicKey(responder_pub, encoder=Base64Encoder)
# this crypto box is for originators (callers, publishers):
#
# 1. _encrypting_ WAMP messages outgoing from originators: CALL*, PUBLISH*
# 2. _decrypting_ WAMP messages incoming to originators: RESULT*, ERROR
#
if self.originator_priv and self.responder_pub:
self.originator_box = Box(self.originator_priv, self.responder_pub)
else:
self.originator_box = None
# this crypto box is for responders (callees, subscribers):
#
# 1. _decrypting_ WAMP messages incoming to responders: INVOCATION*, EVENT*
# 2. _encrypting_ WAMP messages outgoing from responders: YIELD*, ERROR
#
if self.responder_priv and self.originator_pub:
self.responder_box = Box(self.responder_priv, self.originator_pub)
else:
self.responder_box = None
if not (self.originator_box or self.responder_box):
raise Exception(
"insufficient keys provided for at least originator or responder role"
)
@public
class SymKey(object):
"""
Holds a symmetric key for an URI.
"""
def __init__(self, raw=None):
pass
@public
class KeyRing(object):
"""
A keyring holds (cryptobox) public-private key pairs for use with WAMP-cryptobox payload
encryption. The keyring can be set on a WAMP session and then transparently will get used
for encrypting and decrypting WAMP message payloads.
"""
@public
def __init__(self, default_key=None):
"""
Create a new key ring to hold public and private keys mapped from an URI space.
"""
assert (
default_key is None
or isinstance(default_key, Key)
or type(default_key == str)
)
self._uri_to_key = StringTrie()
if type(default_key) == str:
default_key = Key(
originator_priv=default_key, responder_priv=default_key
)
self._default_key = default_key
@public
def generate_key(self):
"""
Generate a new private key and return a pair with the base64 encodings
of (priv_key, pub_key).
"""
key = PrivateKey.generate()
priv_key = key.encode(encoder=Base64Encoder)
pub_key = key.public_key.encode(encoder=Base64Encoder)
return priv_key.decode("ascii"), pub_key.decode("ascii")
@public
def generate_key_hex(self):
"""
Generate a new private key and return a pair with the hex encodings
of (priv_key, pub_key).
"""
key = PrivateKey.generate()
priv_key = key.encode(encoder=HexEncoder)
pub_key = key.public_key.encode(encoder=HexEncoder)
return priv_key.decode("ascii"), pub_key.decode("ascii")
@public
def set_key(self, uri, key):
"""
Add a key set for a given URI.
"""
assert type(uri) == str
assert key is None or isinstance(key, Key) or type(key) == str
if type(key) == str:
key = Key(originator_priv=key, responder_priv=key)
if uri == "":
self._default_key = key
else:
if key is None:
if uri in self._uri_to_key:
del self._uri_to_key[uri]
else:
self._uri_to_key[uri] = key
@public
def rotate_key(self, uri):
assert type(uri) == str
if uri in self._uri_to_key:
self._uri_to_key[uri].rotate()
else:
self._uri_to_key[uri].rotate()
def _get_box(self, is_originating, uri, match_exact=False):
try:
if match_exact:
key = self._uri_to_key[uri]
else:
key = self._uri_to_key.longest_prefix_value(uri)
except KeyError:
if self._default_key:
key = self._default_key
else:
return None
if is_originating:
return key.originator_box
else:
return key.responder_box
@public
def encode(self, is_originating, uri, args=None, kwargs=None):
"""
Encrypt the given WAMP URI, args and kwargs into an EncodedPayload instance, or None
if the URI should not be encrypted.
"""
assert type(is_originating) == bool
assert type(uri) == str
assert args is None or type(args) in (list, tuple)
assert kwargs is None or type(kwargs) == dict
box = self._get_box(is_originating, uri)
if not box:
# if we didn't find a crypto box, then return None, which
# signals that the payload travel unencrypted (normal)
return None
payload = {"uri": uri, "args": args, "kwargs": kwargs}
nonce = random(Box.NONCE_SIZE)
payload_ser = _json_dumps(payload).encode("utf8")
payload_encr = box.encrypt(payload_ser, nonce, encoder=RawEncoder)
# above returns an instance of http://pynacl.readthedocs.io/en/latest/utils/#nacl.utils.EncryptedMessage
# which is a bytes _subclass_! hence we apply bytes() to get at the underlying plain
# bytes "scalar", which is the concatenation of `payload_encr.nonce + payload_encr.ciphertext`
payload_bytes = bytes(payload_encr)
payload_key = None
return EncodedPayload(
payload_bytes, "cryptobox", "json", enc_key=payload_key
)
@public
def decode(self, is_originating, uri, encoded_payload):
"""
Decrypt the given WAMP URI and EncodedPayload into a tuple ``(uri, args, kwargs)``.
"""
assert type(uri) == str
assert isinstance(encoded_payload, EncodedPayload)
assert encoded_payload.enc_algo == "cryptobox"
box = self._get_box(is_originating, uri)
if not box:
raise Exception("received encrypted payload, but can't find key!")
payload_ser = box.decrypt(encoded_payload.payload, encoder=RawEncoder)
if encoded_payload.enc_serializer != "json":
raise Exception(
"received encrypted payload, but don't know how to process serializer '{}'".format(
encoded_payload.enc_serializer
)
)
payload = _json_loads(payload_ser.decode("utf8"))
uri = payload.get("uri", None)
args = payload.get("args", None)
kwargs = payload.get("kwargs", None)
return uri, args, kwargs
# A WAMP-cryptobox keyring can work as a codec for
# payload transparency
IPayloadCodec.register(KeyRing)