import time import uuid from contextlib import contextmanager from typing import IO, TYPE_CHECKING, Any, Callable, Iterator, Optional, Sequence from unittest import mock, skipUnless import DNS import orjson from circuitbreaker import CircuitBreakerMonitor from django.conf import settings from django.core.exceptions import ValidationError from django.test import override_settings from django.utils.timezone import now as timezone_now from zerver.forms import email_is_not_mit_mailing_list from zerver.lib.cache import cache_delete from zerver.lib.rate_limiter import ( RateLimitedIPAddr, RateLimitedUser, RateLimiterLockingError, add_ratelimit_rule, get_tor_ips, remove_ratelimit_rule, ) from zerver.lib.test_classes import ZulipTestCase from zerver.lib.zephyr import compute_mit_user_fullname from zerver.models import PushDeviceToken, UserProfile if settings.ZILENCER_ENABLED: from zilencer.models import RateLimitedRemoteZulipServer, RemoteZulipServer if TYPE_CHECKING: from django.test.client import _MonkeyPatchedWSGIResponse as TestHttpResponse class MITNameTest(ZulipTestCase): def test_valid_hesiod(self) -> None: with mock.patch( "DNS.dnslookup", return_value=[ ["starnine:*:84233:101:Athena Consulting Exchange User,,,:/mit/starnine:/bin/bash"] ], ): self.assertEqual( compute_mit_user_fullname(self.mit_email("starnine")), "Athena Consulting Exchange User", ) with mock.patch( "DNS.dnslookup", return_value=[["sipbexch:*:87824:101:Exch Sipb,,,:/mit/sipbexch:/bin/athena/bash"]], ): self.assertEqual(compute_mit_user_fullname("sipbexch@mit.edu"), "Exch Sipb") def test_invalid_hesiod(self) -> None: with mock.patch( "DNS.dnslookup", side_effect=DNS.Base.ServerError("DNS query status: NXDOMAIN", 3) ): self.assertEqual(compute_mit_user_fullname("1234567890@mit.edu"), "1234567890@mit.edu") with mock.patch( "DNS.dnslookup", side_effect=DNS.Base.ServerError("DNS query status: NXDOMAIN", 3) ): self.assertEqual(compute_mit_user_fullname("ec-discuss@mit.edu"), "ec-discuss@mit.edu") def test_mailinglist(self) -> None: with mock.patch( "DNS.dnslookup", side_effect=DNS.Base.ServerError("DNS query status: NXDOMAIN", 3) ): self.assertRaises(ValidationError, email_is_not_mit_mailing_list, "1234567890@mit.edu") with mock.patch( "DNS.dnslookup", side_effect=DNS.Base.ServerError("DNS query status: NXDOMAIN", 3) ): self.assertRaises(ValidationError, email_is_not_mit_mailing_list, "ec-discuss@mit.edu") def test_notmailinglist(self) -> None: with mock.patch("DNS.dnslookup", return_value=[["POP IMAP.EXCHANGE.MIT.EDU starnine"]]): email_is_not_mit_mailing_list("sipbexch@mit.edu") @contextmanager def rate_limit_rule(range_seconds: int, num_requests: int, domain: str) -> Iterator[None]: RateLimitedIPAddr("127.0.0.1", domain=domain).clear_history() add_ratelimit_rule(range_seconds, num_requests, domain=domain) try: yield finally: # We need this in a finally block to ensure the test cleans up after itself # even in case of failure, to avoid polluting the rules state. remove_ratelimit_rule(range_seconds, num_requests, domain=domain) class RateLimitTests(ZulipTestCase): def setUp(self) -> None: super().setUp() # Some tests here can be somewhat timing-sensitive in a way # that can't be eliminated, e.g. due to testing things that rely # on Redis' internal timing mechanism which we can't mock. # The first API request when running a suite of tests is slow # and can take multiple seconds. This is not a problem when running # multiple tests, but if an individual, time-sensitive test from this class # is run, the first API request it makes taking a lot of time can throw things off # and cause the test to fail. Thus we do a dummy API request here to warm up # the system and allow the tests to assume their requests won't take multiple seconds. user = self.example_user("hamlet") self.api_get(user, "/api/v1/messages") settings.RATE_LIMITING = True def tearDown(self) -> None: settings.RATE_LIMITING = False super().tearDown() def send_api_message(self, user: UserProfile, content: str) -> "TestHttpResponse": return self.api_post( user, "/api/v1/messages", { "type": "stream", "to": orjson.dumps("Verona").decode(), "content": content, "topic": "whatever", }, ) def send_unauthed_api_request(self, **kwargs: Any) -> "TestHttpResponse": result = self.client_get("/json/messages", **kwargs) # We're not making a correct request here, but rate-limiting is supposed # to happen before the request fails due to not being correctly made. Thus # we expect either an 400 error if the request is allowed by the rate limiter, # or 429 if we're above the limit. We don't expect to see other status codes here, # so we assert for safety. self.assertIn(result.status_code, [400, 429]) return result def test_headers(self) -> None: user = self.example_user("hamlet") RateLimitedUser(user).clear_history() result = self.send_api_message(user, "some stuff") self.assertTrue("X-RateLimit-Remaining" in result.headers) self.assertTrue("X-RateLimit-Limit" in result.headers) self.assertTrue("X-RateLimit-Reset" in result.headers) def test_ratelimit_decrease(self) -> None: user = self.example_user("hamlet") RateLimitedUser(user).clear_history() result = self.send_api_message(user, "some stuff") limit = int(result["X-RateLimit-Remaining"]) result = self.send_api_message(user, "some stuff 2") newlimit = int(result["X-RateLimit-Remaining"]) self.assertEqual(limit, newlimit + 1) def do_test_hit_ratelimits( self, request_func: Callable[[], "TestHttpResponse"], is_json: bool = True, ) -> None: def api_assert_func(result: "TestHttpResponse") -> None: self.assertEqual(result.status_code, 429) self.assertEqual(result.headers["Content-Type"], "application/json") json = result.json() self.assertEqual(json.get("result"), "error") self.assertIn("API usage exceeded rate limit", json.get("msg")) self.assertEqual(json.get("retry-after"), 0.5) self.assertTrue("Retry-After" in result.headers) self.assertEqual(result["Retry-After"], "0.5") def user_facing_assert_func(result: "TestHttpResponse") -> None: self.assertEqual(result.status_code, 429) self.assertNotEqual(result.headers["Content-Type"], "application/json") self.assert_in_response("Rate limit exceeded.", result) if is_json: assert_func = api_assert_func else: assert_func = user_facing_assert_func start_time = time.time() for i in range(6): with mock.patch("time.time", return_value=(start_time + i * 0.1)): result = request_func() if i < 5: self.assertNotEqual(result.status_code, 429) assert_func(result) # We simulate waiting a second here, rather than force-clearing our history, # to make sure the rate-limiting code automatically forgives a user # after some time has passed. with mock.patch("time.time", return_value=(start_time + 1.01)): result = request_func() self.assertNotEqual(result.status_code, 429) @rate_limit_rule(1, 5, domain="api_by_user") def test_hit_ratelimits_as_user(self) -> None: user = self.example_user("cordelia") RateLimitedUser(user).clear_history() self.do_test_hit_ratelimits(lambda: self.send_api_message(user, "some stuff")) @rate_limit_rule(1, 5, domain="email_change_by_user") def test_hit_change_email_ratelimit_as_user(self) -> None: user = self.example_user("cordelia") RateLimitedUser(user).clear_history() emails = ["new-email-{n}@zulip.com" for n in range(1, 8)] self.do_test_hit_ratelimits( lambda: self.api_patch(user, "/api/v1/settings", {"email": emails.pop()}), ) @rate_limit_rule(1, 5, domain="api_by_ip") def test_hit_ratelimits_as_ip(self) -> None: self.do_test_hit_ratelimits(self.send_unauthed_api_request) # Other IPs should not be rate-limited resp = self.send_unauthed_api_request(REMOTE_ADDR="127.0.0.2") self.assertNotEqual(resp.status_code, 429) @rate_limit_rule(1, 5, domain="sends_email_by_ip") def test_create_realm_rate_limiting(self) -> None: with self.settings(OPEN_REALM_CREATION=True): self.do_test_hit_ratelimits( lambda: self.client_post("/new/", {"email": "new@zulip.com"}), is_json=False, ) @rate_limit_rule(1, 5, domain="sends_email_by_ip") def test_find_account_rate_limiting(self) -> None: self.do_test_hit_ratelimits( lambda: self.client_post("/accounts/find/", {"emails": "new@zulip.com"}), is_json=False, ) @rate_limit_rule(1, 5, domain="sends_email_by_ip") def test_password_reset_rate_limiting(self) -> None: with self.assertLogs(level="INFO") as m: self.do_test_hit_ratelimits( lambda: self.client_post("/accounts/password/reset/", {"email": "new@zulip.com"}), is_json=False, ) self.assertEqual( m.output, ["INFO:root:Too many password reset attempts for email new@zulip.com from 127.0.0.1"], ) # Test whether submitting multiple emails is handled correctly. # The limit is set to 10 per second, so 5 requests with 2 emails # submitted in each should be allowed. @rate_limit_rule(1, 10, domain="sends_email_by_ip") def test_find_account_rate_limiting_multiple(self) -> None: self.do_test_hit_ratelimits( lambda: self.client_post("/accounts/find/", {"emails": "new@zulip.com,new2@zulip.com"}), is_json=False, ) # If I submit with 3 emails and the rate-limit is 2, I should get # a 429 and not send any emails. @rate_limit_rule(1, 2, domain="sends_email_by_ip") def test_find_account_rate_limiting_multiple_one_request(self) -> None: emails = [ "iago@zulip.com", "cordelia@zulip.com", "hamlet@zulip.com", ] resp = self.client_post("/accounts/find/", {"emails": ",".join(emails)}) self.assertEqual(resp.status_code, 429) from django.core.mail import outbox self.assert_length(outbox, 0) @rate_limit_rule(1, 5, domain="sends_email_by_ip") def test_register_account_rate_limiting(self) -> None: self.do_test_hit_ratelimits( lambda: self.client_post("/register/", {"email": "new@zulip.com"}), is_json=False, ) @rate_limit_rule(1, 5, domain="sends_email_by_ip") def test_combined_ip_limits(self) -> None: # Alternate requests to /new/ and /accounts/find/ request_count = 0 def alternate_requests() -> "TestHttpResponse": nonlocal request_count request_count += 1 if request_count % 2 == 1: return self.client_post("/new/", {"email": "new@zulip.com"}) else: return self.client_post("/accounts/find/", {"emails": "new@zulip.com"}) self.do_test_hit_ratelimits(alternate_requests, is_json=False) @contextmanager def tor_mock( self, side_effect: Optional[Exception] = None, read_data: Sequence[str] = ["1.2.3.4", "5.6.7.8"], ) -> Iterator[mock.Mock]: # We need to reset the circuitbreaker before starting. We # patch the .opened property to be false, then call the # function, so it resets to closed. with mock.patch("builtins.open", mock.mock_open(read_data=orjson.dumps(["1.2.3.4"]))): with mock.patch( "circuitbreaker.CircuitBreaker.opened", new_callable=mock.PropertyMock ) as mock_opened: mock_opened.return_value = False get_tor_ips() # Having closed it, it's now cached. Clear the cache. assert CircuitBreakerMonitor.get("get_tor_ips").closed cache_delete("tor_ip_addresses:") builtin_open = open if side_effect: tor_open = mock.MagicMock(side_effect=side_effect) else: tor_open = mock.mock_open(read_data=orjson.dumps(read_data)) def selective_mock_open(*args: Any, **kwargs: Any) -> IO[Any]: if args[0] == settings.TOR_EXIT_NODE_FILE_PATH: return tor_open(*args, **kwargs) return builtin_open(*args, **kwargs) with mock.patch("builtins.open", selective_mock_open): yield tor_open @rate_limit_rule(1, 5, domain="api_by_ip") @override_settings(RATE_LIMIT_TOR_TOGETHER=True) def test_tor_ip_limits(self) -> None: request_count = 0 for ip in ["1.2.3.4", "5.6.7.8", "tor-exit-node"]: RateLimitedIPAddr(ip, domain="api_by_ip").clear_history() def alternate_requests() -> "TestHttpResponse": nonlocal request_count request_count += 1 if request_count % 2 == 1: return self.send_unauthed_api_request(REMOTE_ADDR="1.2.3.4") else: return self.send_unauthed_api_request(REMOTE_ADDR="5.6.7.8") with self.tor_mock(read_data=["1.2.3.4", "5.6.7.8"]) as tor_open: self.do_test_hit_ratelimits(alternate_requests) # This is only read once, despite being used on each request tor_open.assert_called_once_with(settings.TOR_EXIT_NODE_FILE_PATH, "rb") tor_open().read.assert_called_once() @rate_limit_rule(1, 5, domain="api_by_ip") @override_settings(RATE_LIMIT_TOR_TOGETHER=True) def test_tor_file_empty(self) -> None: for ip in ["1.2.3.4", "5.6.7.8", "tor-exit-node"]: RateLimitedIPAddr(ip, domain="api_by_ip").clear_history() # An empty list of IPs is treated as some error in parsing the # input, and as such should not be cached; rate-limiting # should work as normal, per-IP with self.tor_mock(read_data=[]) as tor_open: with self.assertLogs("zerver.lib.rate_limiter", level="WARNING"): self.do_test_hit_ratelimits( lambda: self.send_unauthed_api_request(REMOTE_ADDR="1.2.3.4") ) resp = self.send_unauthed_api_request(REMOTE_ADDR="5.6.7.8") self.assertNotEqual(resp.status_code, 429) # Was not cached, so tried to read twice before hitting the # circuit-breaker, and stopping trying tor_open().read.assert_has_calls([mock.call(), mock.call()]) @rate_limit_rule(1, 5, domain="api_by_ip") @override_settings(RATE_LIMIT_TOR_TOGETHER=True) def test_tor_file_not_found(self) -> None: for ip in ["1.2.3.4", "5.6.7.8", "tor-exit-node"]: RateLimitedIPAddr(ip, domain="api_by_ip").clear_history() with self.tor_mock(side_effect=FileNotFoundError("File not found")) as tor_open: # If we cannot get a list of TOR exit nodes, then # rate-limiting works as normal, per-IP with self.assertLogs("zerver.lib.rate_limiter", level="WARNING") as log_mock: self.do_test_hit_ratelimits( lambda: self.send_unauthed_api_request(REMOTE_ADDR="1.2.3.4") ) resp = self.send_unauthed_api_request(REMOTE_ADDR="5.6.7.8") self.assertNotEqual(resp.status_code, 429) # Tries twice before hitting the circuit-breaker, and stopping trying tor_open.assert_has_calls( [ mock.call(settings.TOR_EXIT_NODE_FILE_PATH, "rb"), mock.call(settings.TOR_EXIT_NODE_FILE_PATH, "rb"), ] ) self.assert_length(log_mock.output, 8) self.assertEqual( log_mock.output[0:2], [ "WARNING:zerver.lib.rate_limiter:Failed to fetch TOR exit node list: {}".format( "File not found" ) ] * 2, ) self.assertIn( 'Failed to fetch TOR exit node list: Circuit "get_tor_ips" OPEN', log_mock.output[3], ) @skipUnless(settings.ZILENCER_ENABLED, "requires zilencer") @rate_limit_rule(1, 5, domain="api_by_remote_server") def test_hit_ratelimits_as_remote_server(self) -> None: server_uuid = str(uuid.uuid4()) server = RemoteZulipServer( uuid=server_uuid, api_key="magic_secret_api_key", hostname="demo.example.com", last_updated=timezone_now(), ) server.save() endpoint = "/api/v1/remotes/push/register" payload = {"user_id": 10, "token": "111222", "token_kind": PushDeviceToken.GCM} try: # Remote servers can only make requests to the root subdomain. original_default_subdomain = self.DEFAULT_SUBDOMAIN self.DEFAULT_SUBDOMAIN = "" RateLimitedRemoteZulipServer(server).clear_history() with self.assertLogs("zilencer.auth", level="WARNING") as m: self.do_test_hit_ratelimits(lambda: self.uuid_post(server_uuid, endpoint, payload)) self.assertEqual( m.output, [ f"WARNING:zilencer.auth:Remote server exceeded rate limits on domain api_by_remote_server" ], ) finally: self.DEFAULT_SUBDOMAIN = original_default_subdomain def test_hit_ratelimiterlockingexception(self) -> None: user = self.example_user("cordelia") RateLimitedUser(user).clear_history() with mock.patch( "zerver.lib.rate_limiter.RedisRateLimiterBackend.incr_ratelimit", side_effect=RateLimiterLockingError, ): with self.assertLogs("zerver.lib.rate_limiter", level="WARNING") as m: result = self.send_api_message(user, "some stuff") self.assertEqual(result.status_code, 429) self.assertEqual( m.output, [ "WARNING:zerver.lib.rate_limiter:Deadlock trying to incr_ratelimit for {}".format( f"RateLimitedUser:{user.id}:api_by_user" ) ], )