def verify_signed_jwt_with_certs(jwt, certs, audience=None):
"""Verify a JWT against public certs.
See http://self-issued.info/docs/draft-jones-json-web-token.html.
Args:
jwt: string, A JWT.
certs: dict, Dictionary where values of public keys in PEM format.
audience: string, The audience, 'aud', that this JWT should contain. If
None then the JWT's 'aud' parameter is not verified.
Returns:
dict, The deserialized JSON payload in the JWT.
Raises:
AppIdentityError: if any checks are failed.
"""
jwt = _helpers._to_bytes(jwt)
if jwt.count(b'.') != 2:
raise AppIdentityError(
'Wrong number of segments in token: {0}'.format(jwt))
header, payload, signature = jwt.split(b'.')
message_to_sign = header + b'.' + payload
signature = _helpers._urlsafe_b64decode(signature)
# Parse token.
payload_bytes = _helpers._urlsafe_b64decode(payload)
try:
payload_dict = json.loads(_helpers._from_bytes(payload_bytes))
except:
raise AppIdentityError('Can\'t parse token: {0}'.format(payload_bytes))
# Verify that the signature matches the message.
_verify_signature(message_to_sign, signature, certs.values())
# Verify the issued at and created times in the payload.
_verify_time_range(payload_dict)
# Check audience.
_check_audience(payload_dict, audience)
return payload_dict
def from_string(key_pem, is_x509_cert):
"""Construct a Verified instance from a string.
Args:
key_pem: string, public key in PEM format.
is_x509_cert: bool, True if key_pem is an X509 cert, otherwise it
is expected to be an RSA key in PEM format.
Returns:
Verifier instance.
"""
if is_x509_cert:
key_pem = _helpers._to_bytes(key_pem)
pemLines = key_pem.replace(b' ', b'').split()
certDer = _helpers._urlsafe_b64decode(b''.join(pemLines[1:-1]))
certSeq = DerSequence()
certSeq.decode(certDer)
tbsSeq = DerSequence()
tbsSeq.decode(certSeq[0])
pubkey = RSA.importKey(tbsSeq[6])
else:
pubkey = RSA.importKey(key_pem)
return PyCryptoVerifier(pubkey)
def from_string(key_pem, is_x509_cert):
"""Construct a Verified instance from a string.
Args:
key_pem: string, public key in PEM format.
is_x509_cert: bool, True if key_pem is an X509 cert, otherwise it
is expected to be an RSA key in PEM format.
Returns:
Verifier instance.
"""
if is_x509_cert:
key_pem = _to_bytes(key_pem)
pemLines = key_pem.replace(b' ', b'').split()
certDer = _urlsafe_b64decode(b''.join(pemLines[1:-1]))
certSeq = DerSequence()
certSeq.decode(certDer)
tbsSeq = DerSequence()
tbsSeq.decode(certSeq[0])
pubkey = RSA.importKey(tbsSeq[6])
else:
pubkey = RSA.importKey(key_pem)
return PyCryptoVerifier(pubkey)
def test_valid_input_unicode(self): test_string = b'ZGVhZGJlZWY' result = _urlsafe_b64decode(test_string) self.assertEqual(result, b'deadbeef')
def test_valid_input_bytes(self):
test_string = b'ZGVhZGJlZWY'
result = _helpers._urlsafe_b64decode(test_string)
self.assertEqual(result, b'deadbeef')
def test_bad_input(self):
import binascii
bad_string = b'+'
with self.assertRaises((TypeError, binascii.Error)):
_helpers._urlsafe_b64decode(bad_string)
def verify_signed_jwt_with_certs(jwt, certs, audience):
"""Verify a JWT against public certs.
See http://self-issued.info/docs/draft-jones-json-web-token.html.
Args:
jwt: string, A JWT.
certs: dict, Dictionary where values of public keys in PEM format.
audience: string, The audience, 'aud', that this JWT should contain. If
None then the JWT's 'aud' parameter is not verified.
Returns:
dict, The deserialized JSON payload in the JWT.
Raises:
AppIdentityError if any checks are failed.
"""
jwt = _to_bytes(jwt)
segments = jwt.split(b'.')
if len(segments) != 3:
raise AppIdentityError('Wrong number of segments in token: %s' % jwt)
signed = segments[0] + b'.' + segments[1]
signature = _urlsafe_b64decode(segments[2])
# Parse token.
json_body = _urlsafe_b64decode(segments[1])
try:
parsed = json.loads(json_body.decode('utf-8'))
except:
raise AppIdentityError('Can\'t parse token: %s' % json_body)
# Check signature.
verified = False
for pem in certs.values():
verifier = Verifier.from_string(pem, True)
if verifier.verify(signed, signature):
verified = True
break
if not verified:
raise AppIdentityError('Invalid token signature: %s' % jwt)
# Check creation timestamp.
iat = parsed.get('iat')
if iat is None:
raise AppIdentityError('No iat field in token: %s' % json_body)
earliest = iat - CLOCK_SKEW_SECS
# Check expiration timestamp.
now = int(time.time())
exp = parsed.get('exp')
if exp is None:
raise AppIdentityError('No exp field in token: %s' % json_body)
if exp >= now + MAX_TOKEN_LIFETIME_SECS:
raise AppIdentityError('exp field too far in future: %s' % json_body)
latest = exp + CLOCK_SKEW_SECS
if now < earliest:
raise AppIdentityError('Token used too early, %d < %d: %s' %
(now, earliest, json_body))
if now > latest:
raise AppIdentityError('Token used too late, %d > %d: %s' %
(now, latest, json_body))
# Check audience.
if audience is not None:
aud = parsed.get('aud')
if aud is None:
raise AppIdentityError('No aud field in token: %s' % json_body)
if aud != audience:
raise AppIdentityError('Wrong recipient, %s != %s: %s' %
(aud, audience, json_body))
return parsed
def verify_signed_jwt_with_certs(jwt, certs, audience):
"""Verify a JWT against public certs.
See http://self-issued.info/docs/draft-jones-json-web-token.html.
Args:
jwt: string, A JWT.
certs: dict, Dictionary where values of public keys in PEM format.
audience: string, The audience, 'aud', that this JWT should contain. If
None then the JWT's 'aud' parameter is not verified.
Returns:
dict, The deserialized JSON payload in the JWT.
Raises:
AppIdentityError if any checks are failed.
"""
jwt = _to_bytes(jwt)
segments = jwt.split(b'.')
if len(segments) != 3:
raise AppIdentityError('Wrong number of segments in token: %s' % jwt)
signed = segments[0] + b'.' + segments[1]
signature = _urlsafe_b64decode(segments[2])
# Parse token.
json_body = _urlsafe_b64decode(segments[1])
try:
parsed = json.loads(json_body.decode('utf-8'))
except:
raise AppIdentityError('Can\'t parse token: %s' % json_body)
# Check signature.
verified = False
for pem in certs.values():
verifier = Verifier.from_string(pem, True)
if verifier.verify(signed, signature):
verified = True
break
if not verified:
raise AppIdentityError('Invalid token signature: %s' % jwt)
# Check creation timestamp.
iat = parsed.get('iat')
if iat is None:
raise AppIdentityError('No iat field in token: %s' % json_body)
earliest = iat - CLOCK_SKEW_SECS
# Check expiration timestamp.
now = int(time.time())
exp = parsed.get('exp')
if exp is None:
raise AppIdentityError('No exp field in token: %s' % json_body)
if exp >= now + MAX_TOKEN_LIFETIME_SECS:
raise AppIdentityError('exp field too far in future: %s' % json_body)
latest = exp + CLOCK_SKEW_SECS
if now < earliest:
raise AppIdentityError('Token used too early, %d < %d: %s' %
(now, earliest, json_body))
if now > latest:
raise AppIdentityError('Token used too late, %d > %d: %s' %
(now, latest, json_body))
# Check audience.
if audience is not None:
aud = parsed.get('aud')
if aud is None:
raise AppIdentityError('No aud field in token: %s' % json_body)
if aud != audience:
raise AppIdentityError('Wrong recipient, %s != %s: %s' %
(aud, audience, json_body))
return parsed
def test_valid_input_unicode(self):
test_string = u'ZGVhZGJlZWY'
result = _helpers._urlsafe_b64decode(test_string)
self.assertEqual(result, self.DEADBEEF_DECODED)
def test_valid_input_bytes(self):
test_string = b"ZGVhZGJlZWY"
result = _urlsafe_b64decode(test_string)
self.assertEqual(result, b"deadbeef")
def test_valid_input_unicode(self):
test_string = u'ZGVhZGJlZWY'
result = _helpers._urlsafe_b64decode(test_string)
self.assertEqual(result, self.DEADBEEF_DECODED)