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Change the format of access tokens away from macaroons (#5588)

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Richard van der Hoff 2021-05-12 15:04:51 +01:00 committed by GitHub
parent affaffb0ab
commit 7562d887e1
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9 changed files with 78 additions and 103 deletions
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1
changelog.d/5588.misc Normal file
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@ -0,0 +1 @@
Reduce the length of Synapse's access tokens.

2
scripts-dev/dump_macaroon.py
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@ -1,4 +1,4 @@
#!/usr/bin/env python2
#!/usr/bin/env python
import sys

28
synapse/handlers/auth.py
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@ -17,6 +17,7 @@ import logging
import time
import unicodedata
import urllib.parse
from binascii import crc32
from typing import (
TYPE_CHECKING,
Any,
@ -34,6 +35,7 @@ from typing import (
import attr
import bcrypt
import pymacaroons
import unpaddedbase64
from twisted.web.server import Request
@ -66,6 +68,7 @@ from synapse.util import stringutils as stringutils
from synapse.util.async_helpers import maybe_awaitable
from synapse.util.macaroons import get_value_from_macaroon, satisfy_expiry
from synapse.util.msisdn import phone_number_to_msisdn
from synapse.util.stringutils import base62_encode
from synapse.util.threepids import canonicalise_email
if TYPE_CHECKING:
@ -808,10 +811,12 @@ class AuthHandler(BaseHandler):
logger.info(
"Logging in user %s as %s%s", user_id, puppets_user_id, fmt_expiry
)
target_user_id_obj = UserID.from_string(puppets_user_id)
else:
logger.info(
"Logging in user %s on device %s%s", user_id, device_id, fmt_expiry
)
target_user_id_obj = UserID.from_string(user_id)
if (
not is_appservice_ghost
@ -819,7 +824,7 @@ class AuthHandler(BaseHandler):
):
await self.auth.check_auth_blocking(user_id)
access_token = self.macaroon_gen.generate_access_token(user_id)
access_token = self.generate_access_token(target_user_id_obj)
await self.store.add_access_token_to_user(
user_id=user_id,
token=access_token,
@ -1192,6 +1197,19 @@ class AuthHandler(BaseHandler):
return None
return user_id
def generate_access_token(self, for_user: UserID) -> str:
"""Generates an opaque string, for use as an access token"""
# we use the following format for access tokens:
# syt_<base64 local part>_<random string>_<base62 crc check>
b64local = unpaddedbase64.encode_base64(for_user.localpart.encode("utf-8"))
random_string = stringutils.random_string(20)
base = f"syt_{b64local}_{random_string}"
crc = base62_encode(crc32(base.encode("ascii")), minwidth=6)
return f"{base}_{crc}"
async def validate_short_term_login_token(
self, login_token: str
) -> LoginTokenAttributes:
@ -1585,10 +1603,7 @@ class MacaroonGenerator:
hs = attr.ib()
def generate_access_token(
self, user_id: str, extra_caveats: Optional[List[str]] = None
) -> str:
extra_caveats = extra_caveats or []
def generate_guest_access_token(self, user_id: str) -> str:
macaroon = self._generate_base_macaroon(user_id)
macaroon.add_first_party_caveat("type = access")
# Include a nonce, to make sure that each login gets a different
@ -1596,8 +1611,7 @@ class MacaroonGenerator:
macaroon.add_first_party_caveat(
"nonce = %s" % (stringutils.random_string_with_symbols(16),)
)
for caveat in extra_caveats:
macaroon.add_first_party_caveat(caveat)
macaroon.add_first_party_caveat("guest = true")
return macaroon.serialize()
def generate_short_term_login_token(

4
synapse/handlers/register.py
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@ -722,9 +722,7 @@ class RegistrationHandler(BaseHandler):
)
if is_guest:
assert valid_until_ms is None
access_token = self.macaroon_gen.generate_access_token(
user_id, ["guest = true"]
)
access_token = self.macaroon_gen.generate_guest_access_token(user_id)
else:
access_token = await self._auth_handler.get_access_token_for_user_id(
user_id,

20
synapse/util/stringutils.py
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@ -220,3 +220,23 @@ def strtobool(val: str) -> bool:
return False
else:
raise ValueError("invalid truth value %r" % (val,))
_BASE62 = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
def base62_encode(num: int, minwidth: int = 1) -> str:
"""Encode a number using base62
Args:
num: number to be encoded
minwidth: width to pad to, if the number is small
"""
res = ""
while num:
num, rem = divmod(num, 62)
res = _BASE62[rem] + res
# pad to minimum width
pad = "0" * (minwidth - len(res))
return pad + res

63
tests/api/test_auth.py
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@ -21,13 +21,11 @@ from synapse.api.constants import UserTypes
from synapse.api.errors import (
AuthError,
Codes,
InvalidClientCredentialsError,
InvalidClientTokenError,
MissingClientTokenError,
ResourceLimitError,
)
from synapse.storage.databases.main.registration import TokenLookupResult
from synapse.types import UserID
from tests import unittest
from tests.test_utils import simple_async_mock
@ -253,67 +251,6 @@ class AuthTestCase(unittest.HomeserverTestCase):
self.assertTrue(user_info.is_guest)
self.store.get_user_by_id.assert_called_with(user_id)
def test_cannot_use_regular_token_as_guest(self):
USER_ID = "@percy:matrix.org"
self.store.add_access_token_to_user = simple_async_mock(None)
self.store.get_device = simple_async_mock(None)
token = self.get_success(
self.hs.get_auth_handler().get_access_token_for_user_id(
USER_ID, "DEVICE", valid_until_ms=None
)
)
self.store.add_access_token_to_user.assert_called_with(
user_id=USER_ID,
token=token,
device_id="DEVICE",
valid_until_ms=None,
puppets_user_id=None,
)
async def get_user(tok):
if token != tok:
return None
return TokenLookupResult(
user_id=USER_ID,
is_guest=False,
token_id=1234,
device_id="DEVICE",
)
self.store.get_user_by_access_token = get_user
self.store.get_user_by_id = simple_async_mock({"is_guest": False})
# check the token works
request = Mock(args={})
request.args[b"access_token"] = [token.encode("ascii")]
request.requestHeaders.getRawHeaders = mock_getRawHeaders()
requester = self.get_success(
self.auth.get_user_by_req(request, allow_guest=True)
)
self.assertEqual(UserID.from_string(USER_ID), requester.user)
self.assertFalse(requester.is_guest)
# add an is_guest caveat
mac = pymacaroons.Macaroon.deserialize(token)
mac.add_first_party_caveat("guest = true")
guest_tok = mac.serialize()
# the token should *not* work now
request = Mock(args={})
request.args[b"access_token"] = [guest_tok.encode("ascii")]
request.requestHeaders.getRawHeaders = mock_getRawHeaders()
cm = self.get_failure(
self.auth.get_user_by_req(request, allow_guest=True),
InvalidClientCredentialsError,
)
self.assertEqual(401, cm.value.code)
self.assertEqual("Guest access token used for regular user", cm.value.msg)
self.store.get_user_by_id.assert_called_with(USER_ID)
def test_blocking_mau(self):
self.auth_blocking._limit_usage_by_mau = False
self.auth_blocking._max_mau_value = 50

43
tests/handlers/test_auth.py
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@ -16,12 +16,17 @@ from unittest.mock import Mock
import pymacaroons
from synapse.api.errors import AuthError, ResourceLimitError
from synapse.rest import admin
from tests import unittest
from tests.test_utils import make_awaitable
class AuthTestCase(unittest.HomeserverTestCase):
servlets = [
admin.register_servlets,
]
def prepare(self, reactor, clock, hs):
self.auth_handler = hs.get_auth_handler()
self.macaroon_generator = hs.get_macaroon_generator()
@ -35,16 +40,10 @@ class AuthTestCase(unittest.HomeserverTestCase):
self.small_number_of_users = 1
self.large_number_of_users = 100
def test_token_is_a_macaroon(self):
token = self.macaroon_generator.generate_access_token("some_user")
# Check that we can parse the thing with pymacaroons
macaroon = pymacaroons.Macaroon.deserialize(token)
# The most basic of sanity checks
if "some_user" not in macaroon.inspect():
self.fail("some_user was not in %s" % macaroon.inspect())
self.user1 = self.register_user("a_user", "pass")
def test_macaroon_caveats(self):
token = self.macaroon_generator.generate_access_token("a_user")
token = self.macaroon_generator.generate_guest_access_token("a_user")
macaroon = pymacaroons.Macaroon.deserialize(token)
def verify_gen(caveat):
@ -59,19 +58,23 @@ class AuthTestCase(unittest.HomeserverTestCase):
def verify_nonce(caveat):
return caveat.startswith("nonce =")
def verify_guest(caveat):
return caveat == "guest = true"
v = pymacaroons.Verifier()
v.satisfy_general(verify_gen)
v.satisfy_general(verify_user)
v.satisfy_general(verify_type)
v.satisfy_general(verify_nonce)
v.satisfy_general(verify_guest)
v.verify(macaroon, self.hs.config.macaroon_secret_key)
def test_short_term_login_token_gives_user_id(self):
token = self.macaroon_generator.generate_short_term_login_token(
"a_user", "", 5000
self.user1, "", 5000
)
res = self.get_success(self.auth_handler.validate_short_term_login_token(token))
self.assertEqual("a_user", res.user_id)
self.assertEqual(self.user1, res.user_id)
self.assertEqual("", res.auth_provider_id)
# when we advance the clock, the token should be rejected
@ -83,22 +86,22 @@ class AuthTestCase(unittest.HomeserverTestCase):
def test_short_term_login_token_gives_auth_provider(self):
token = self.macaroon_generator.generate_short_term_login_token(
"a_user", auth_provider_id="my_idp"
self.user1, auth_provider_id="my_idp"
)
res = self.get_success(self.auth_handler.validate_short_term_login_token(token))
self.assertEqual("a_user", res.user_id)
self.assertEqual(self.user1, res.user_id)
self.assertEqual("my_idp", res.auth_provider_id)
def test_short_term_login_token_cannot_replace_user_id(self):
token = self.macaroon_generator.generate_short_term_login_token(
"a_user", "", 5000
self.user1, "", 5000
)
macaroon = pymacaroons.Macaroon.deserialize(token)
res = self.get_success(
self.auth_handler.validate_short_term_login_token(macaroon.serialize())
)
self.assertEqual("a_user", res.user_id)
self.assertEqual(self.user1, res.user_id)
# add another "user_id" caveat, which might allow us to override the
# user_id.
@ -114,7 +117,7 @@ class AuthTestCase(unittest.HomeserverTestCase):
# Ensure does not throw exception
self.get_success(
self.auth_handler.get_access_token_for_user_id(
"user_a", device_id=None, valid_until_ms=None
self.user1, device_id=None, valid_until_ms=None
)
)
@ -132,7 +135,7 @@ class AuthTestCase(unittest.HomeserverTestCase):
self.get_failure(
self.auth_handler.get_access_token_for_user_id(
"user_a", device_id=None, valid_until_ms=None
self.user1, device_id=None, valid_until_ms=None
),
ResourceLimitError,
)
@ -160,7 +163,7 @@ class AuthTestCase(unittest.HomeserverTestCase):
# If not in monthly active cohort
self.get_failure(
self.auth_handler.get_access_token_for_user_id(
"user_a", device_id=None, valid_until_ms=None
self.user1, device_id=None, valid_until_ms=None
),
ResourceLimitError,
)
@ -177,7 +180,7 @@ class AuthTestCase(unittest.HomeserverTestCase):
)
self.get_success(
self.auth_handler.get_access_token_for_user_id(
"user_a", device_id=None, valid_until_ms=None
self.user1, device_id=None, valid_until_ms=None
)
)
self.get_success(
@ -195,7 +198,7 @@ class AuthTestCase(unittest.HomeserverTestCase):
# Ensure does not raise exception
self.get_success(
self.auth_handler.get_access_token_for_user_id(
"user_a", device_id=None, valid_until_ms=None
self.user1, device_id=None, valid_until_ms=None
)
)
@ -210,6 +213,6 @@ class AuthTestCase(unittest.HomeserverTestCase):
def _get_macaroon(self):
token = self.macaroon_generator.generate_short_term_login_token(
"user_a", "", 5000
self.user1, "", 5000
)
return pymacaroons.Macaroon.deserialize(token)

12
tests/handlers/test_register.py
View file

@ -48,10 +48,6 @@ class RegistrationTestCase(unittest.HomeserverTestCase):
self.mock_distributor = Mock()
self.mock_distributor.declare("registered_user")
self.mock_captcha_client = Mock()
self.macaroon_generator = Mock(
generate_access_token=Mock(return_value="secret")
)
self.hs.get_macaroon_generator = Mock(return_value=self.macaroon_generator)
self.handler = self.hs.get_registration_handler()
self.store = self.hs.get_datastore()
self.lots_of_users = 100
@ -67,8 +63,8 @@ class RegistrationTestCase(unittest.HomeserverTestCase):
self.get_or_create_user(requester, frank.localpart, "Frankie")
)
self.assertEquals(result_user_id, user_id)
self.assertTrue(result_token is not None)
self.assertEquals(result_token, "secret")
self.assertIsInstance(result_token, str)
self.assertGreater(len(result_token), 20)
def test_if_user_exists(self):
store = self.hs.get_datastore()
@ -500,7 +496,7 @@ class RegistrationTestCase(unittest.HomeserverTestCase):
user_id = self.get_success(self.handler.register_user(localpart="user"))
# Get an access token.
token = self.macaroon_generator.generate_access_token(user_id)
token = "testtok"
self.get_success(
self.store.add_access_token_to_user(
user_id=user_id, token=token, device_id=None, valid_until_ms=None
@ -577,7 +573,7 @@ class RegistrationTestCase(unittest.HomeserverTestCase):
user = UserID(localpart, self.hs.hostname)
user_id = user.to_string()
token = self.macaroon_generator.generate_access_token(user_id)
token = self.hs.get_auth_handler().generate_access_token(user)
if need_register:
await self.handler.register_with_store(

8
tests/util/test_stringutils.py
View file

@ -13,7 +13,7 @@
# limitations under the License.
from synapse.api.errors import SynapseError
from synapse.util.stringutils import assert_valid_client_secret
from synapse.util.stringutils import assert_valid_client_secret, base62_encode
from .. import unittest
@ -45,3 +45,9 @@ class StringUtilsTestCase(unittest.TestCase):
for client_secret in bad:
with self.assertRaises(SynapseError):
assert_valid_client_secret(client_secret)
def test_base62_encode(self):
self.assertEqual("0", base62_encode(0))
self.assertEqual("10", base62_encode(62))
self.assertEqual("1c", base62_encode(100))
self.assertEqual("001c", base62_encode(100, minwidth=4))