205 lines
6.6 KiB
Python
205 lines
6.6 KiB
Python
import binascii
|
|
import json
|
|
import warnings
|
|
|
|
from collections import Mapping
|
|
|
|
from .algorithms import Algorithm, get_default_algorithms # NOQA
|
|
from .compat import binary_type, string_types, text_type
|
|
from .exceptions import DecodeError, InvalidAlgorithmError, InvalidTokenError
|
|
from .utils import base64url_decode, base64url_encode, merge_dict
|
|
|
|
|
|
class PyJWS(object):
|
|
header_typ = 'JWT'
|
|
|
|
def __init__(self, algorithms=None, options=None):
|
|
self._algorithms = get_default_algorithms()
|
|
self._valid_algs = (set(algorithms) if algorithms is not None
|
|
else set(self._algorithms))
|
|
|
|
# Remove algorithms that aren't on the whitelist
|
|
for key in list(self._algorithms.keys()):
|
|
if key not in self._valid_algs:
|
|
del self._algorithms[key]
|
|
|
|
if not options:
|
|
options = {}
|
|
|
|
self.options = merge_dict(self._get_default_options(), options)
|
|
|
|
@staticmethod
|
|
def _get_default_options():
|
|
return {
|
|
'verify_signature': True
|
|
}
|
|
|
|
def register_algorithm(self, alg_id, alg_obj):
|
|
"""
|
|
Registers a new Algorithm for use when creating and verifying tokens.
|
|
"""
|
|
if alg_id in self._algorithms:
|
|
raise ValueError('Algorithm already has a handler.')
|
|
|
|
if not isinstance(alg_obj, Algorithm):
|
|
raise TypeError('Object is not of type `Algorithm`')
|
|
|
|
self._algorithms[alg_id] = alg_obj
|
|
self._valid_algs.add(alg_id)
|
|
|
|
def unregister_algorithm(self, alg_id):
|
|
"""
|
|
Unregisters an Algorithm for use when creating and verifying tokens
|
|
Throws KeyError if algorithm is not registered.
|
|
"""
|
|
if alg_id not in self._algorithms:
|
|
raise KeyError('The specified algorithm could not be removed'
|
|
' because it is not registered.')
|
|
|
|
del self._algorithms[alg_id]
|
|
self._valid_algs.remove(alg_id)
|
|
|
|
def get_algorithms(self):
|
|
"""
|
|
Returns a list of supported values for the 'alg' parameter.
|
|
"""
|
|
return list(self._valid_algs)
|
|
|
|
def encode(self, payload, key, algorithm='HS256', headers=None,
|
|
json_encoder=None):
|
|
segments = []
|
|
|
|
if algorithm is None:
|
|
algorithm = 'none'
|
|
|
|
if algorithm not in self._valid_algs:
|
|
pass
|
|
|
|
# Header
|
|
header = {'typ': self.header_typ, 'alg': algorithm}
|
|
|
|
if headers:
|
|
self._validate_headers(headers)
|
|
header.update(headers)
|
|
|
|
json_header = json.dumps(
|
|
header,
|
|
separators=(',', ':'),
|
|
cls=json_encoder
|
|
).encode('utf-8')
|
|
|
|
segments.append(base64url_encode(json_header))
|
|
segments.append(base64url_encode(payload))
|
|
|
|
# Segments
|
|
signing_input = b'.'.join(segments)
|
|
try:
|
|
alg_obj = self._algorithms[algorithm]
|
|
key = alg_obj.prepare_key(key)
|
|
signature = alg_obj.sign(signing_input, key)
|
|
|
|
except KeyError:
|
|
raise NotImplementedError('Algorithm not supported')
|
|
|
|
segments.append(base64url_encode(signature))
|
|
|
|
return b'.'.join(segments)
|
|
|
|
def decode(self, jws, key='', verify=True, algorithms=None, options=None,
|
|
**kwargs):
|
|
payload, signing_input, header, signature = self._load(jws)
|
|
|
|
if verify:
|
|
merged_options = merge_dict(self.options, options)
|
|
if merged_options.get('verify_signature'):
|
|
self._verify_signature(payload, signing_input, header, signature,
|
|
key, algorithms)
|
|
else:
|
|
warnings.warn('The verify parameter is deprecated. '
|
|
'Please use options instead.', DeprecationWarning)
|
|
|
|
return payload
|
|
|
|
def get_unverified_header(self, jwt):
|
|
"""Returns back the JWT header parameters as a dict()
|
|
|
|
Note: The signature is not verified so the header parameters
|
|
should not be fully trusted until signature verification is complete
|
|
"""
|
|
headers = self._load(jwt)[2]
|
|
self._validate_headers(headers)
|
|
|
|
return headers
|
|
|
|
def _load(self, jwt):
|
|
if isinstance(jwt, text_type):
|
|
jwt = jwt.encode('utf-8')
|
|
|
|
if not issubclass(type(jwt), binary_type):
|
|
raise DecodeError("Invalid token type. Token must be a {0}".format(
|
|
binary_type))
|
|
|
|
try:
|
|
signing_input, crypto_segment = jwt.rsplit(b'.', 1)
|
|
header_segment, payload_segment = signing_input.split(b'.', 1)
|
|
except ValueError:
|
|
raise DecodeError('Not enough segments')
|
|
|
|
try:
|
|
header_data = base64url_decode(header_segment)
|
|
except (TypeError, binascii.Error):
|
|
raise DecodeError('Invalid header padding')
|
|
|
|
try:
|
|
header = json.loads(header_data.decode('utf-8'))
|
|
except ValueError as e:
|
|
raise DecodeError('Invalid header string: %s' % e)
|
|
|
|
if not isinstance(header, Mapping):
|
|
raise DecodeError('Invalid header string: must be a json object')
|
|
|
|
try:
|
|
payload = base64url_decode(payload_segment)
|
|
except (TypeError, binascii.Error):
|
|
raise DecodeError('Invalid payload padding')
|
|
|
|
try:
|
|
signature = base64url_decode(crypto_segment)
|
|
except (TypeError, binascii.Error):
|
|
raise DecodeError('Invalid crypto padding')
|
|
|
|
return (payload, signing_input, header, signature)
|
|
|
|
def _verify_signature(self, payload, signing_input, header, signature,
|
|
key='', algorithms=None):
|
|
|
|
alg = header.get('alg')
|
|
|
|
if algorithms is not None and alg not in algorithms:
|
|
raise InvalidAlgorithmError('The specified alg value is not allowed')
|
|
|
|
try:
|
|
alg_obj = self._algorithms[alg]
|
|
key = alg_obj.prepare_key(key)
|
|
|
|
if not alg_obj.verify(signing_input, key, signature):
|
|
raise DecodeError('Signature verification failed')
|
|
|
|
except KeyError:
|
|
raise InvalidAlgorithmError('Algorithm not supported')
|
|
|
|
def _validate_headers(self, headers):
|
|
if 'kid' in headers:
|
|
self._validate_kid(headers['kid'])
|
|
|
|
def _validate_kid(self, kid):
|
|
if not isinstance(kid, string_types):
|
|
raise InvalidTokenError('Key ID header parameter must be a string')
|
|
|
|
_jws_global_obj = PyJWS()
|
|
encode = _jws_global_obj.encode
|
|
decode = _jws_global_obj.decode
|
|
register_algorithm = _jws_global_obj.register_algorithm
|
|
unregister_algorithm = _jws_global_obj.unregister_algorithm
|
|
get_unverified_header = _jws_global_obj.get_unverified_header
|