TOR users are legitimate users of the system; however, that system can
also be used for abuse -- specifically, by evading IP-based
rate-limiting.
For the purposes of IP-based rate-limiting, add a
RATE_LIMIT_TOR_TOGETHER flag, defaulting to false, which lumps all
requests from TOR exit nodes into the same bucket. This may allow a
TOR user to deny other TOR users access to the find-my-account and
new-realm endpoints, but this is a low cost for cutting off a
significant potential abuse vector.
If enabled, the list of TOR exit nodes is fetched from their public
endpoint once per hour, via a cron job, and cached on disk. Django
processes load this data from disk, and cache it in memcached.
Requests are spared from the burden of checking disk on failure via a
circuitbreaker, which trips of there are two failures in a row, and
only begins trying again after 10 minutes.
The decorator form is clearer by being more explicit; additionally,
the api_by_user rate-limit only currently used in one place, and makes
it difficult to test per-user rate-limits that are more specific.
Both `create_realm_by_ip` and `find_account_by_ip` send emails to
arbitrary email addresses, and as such can be used to spam users.
Lump their IP rate limits into the same bucket; most legitimate users
will likely not be using both of these endpoints at similar times.
The rate is set at 5 in 30 minutes, the more quickly-restrictive of
the two previous rates.
The existing test did no verify that the rate limit only applied to
127.0.0.1, and that other IPs were unaffected. For safety, add an
explicit test of this.
The only use case of rate_limit_rule which does not clear the
RateLimitedIPAddr history is test_hit_ratelimits_as_remote_server,
which is not made any worse by clearing out the IP history for a
non-existent `api_by_remote_server` domain.
Closes#19287
This endpoint allows submitting multiple addresses so we need to "weigh"
the rate limit more heavily the more emails are submitted. Clearly e.g.
a request triggering emails to 2 addresses should weigh twice as much as
a request doing that for just 1 address.
We don't want this rate limit to affect legitimate users so it being hit
should be abnormal - thus worth logging so that we can spot if we're
rate limiting legitimate users and can know to increase the limit.
If the user is logged in, we'll stick to rate limiting by the
UserProfile. In case of requests without authentication, we'll apply the
same limits but to the IP address.
I noticed RateLimitTests.test_hit_ratelimits fails when run as an
individual test, but never when run after other tests. That's due to the
first API request in a run of tests taking a long time, as detailed in
the comment on the change to the setUp method.
Fixes#2665.
Regenerated by tabbott with `lint --fix` after a rebase and change in
parameters.
Note from tabbott: In a few cases, this converts technical debt in the
form of unsorted imports into different technical debt in the form of
our largest files having very long, ugly import sequences at the
start. I expect this change will increase pressure for us to split
those files, which isn't a bad thing.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
mock is just a backport of the standard library’s unittest.mock now.
The SAMLAuthBackendTest change is needed because
MagicMock.call_args.args wasn’t introduced until Python
3.8 (https://bugs.python.org/issue21269).
The PROVISION_VERSION bump is skipped because mock is still an
indirect dev requirement via moto.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
Generated by `pyupgrade --py3-plus --keep-percent-format` on all our
Python code except `zthumbor` and `zulip-ec2-configure-interfaces`,
followed by manual indentation fixes.
Signed-off-by: Anders Kaseorg <anders@zulipchat.com>
If we had a rule like "max 3 requests in 2 seconds", there was an
inconsistency between is_ratelimited() and get_api_calls_left().
If you had:
request #1 at time 0
request #2 and #3 at some times < 2
Next request, if exactly at time 2, would not get ratelimited, but if
get_api_calls_left was called, it would return 0. This was due to
inconsistency on the boundary - the check in is_ratelimited was
exclusive, while get_api_calls_left uses zcount, which is inclusive.
type().__name__ is sufficient, and much readable than type(), so it's
better to use the former for keys.
We also make the classes consistent in forming the keys in the format
type(self).__name__:identifier and adjust logger.warning and statsd to
take advantage of that and simply log the key().
This reduces query counts in some cases, since
we no longer need to look up the user again. In
particular, it reduces some noise when we
count queries for O(N)-related tests.
The query count is usually reduced by 2 per
API call. We no longer need to look up Realm
and UserProfile. In most cases we are saving
these lookups for the whole tests, since we
usually already have the `user` objects for
other reasons. In a few places we are simply
moving where that query happens within the
test.
In some places I shorten names like `test_user`
or `user_profile` to just be `user`.
MigrationsTestCase is intentionally omitted from this, since migrations
tests are different in their nature and so whatever setUp()
ZulipTestCase may do in the future, MigrationsTestCase may not
necessarily want to replicate.
We create rate_limit_entity as a general rate-limiting function for
RateLimitedObjects, from code that was possible to abstract away from
rate_limit_user and that will be used for other kinds of rate limiting.
We make rate_limit_user use this new general framework from now.
Right now it only has one function, but the function
we removed never really belonged in actions.py, and
now we have better test coverage on actions.py, which
is an important module to get to 100%.
Alex Vandiver
Tim Abbott
Mateusz Mandera
Anders Kaseorg
palash
Anders Kaseorg
Mateusz Mandera
Steve Howell
Anders Kaseorg
Aditya Bansal
Alena Volkova
rht