The issue
---
When using rack-attack with a rails app, developers expect the request
path to be normalized. In particular, trailing slashes are stripped so
a request path "/login/" becomes "/login" by the time you're in
ActionController.
Since Rack::Attack runs before ActionDispatch, the request path is not
yet normalized. This can cause throttles and blacklists to not work as
expected.
E.g., a throttle:
throttle('logins', ...) {|req| req.path == "/login" }
would not match a request to '/login/', though Rails would route
'/login/' to the same '/login' action.
The solution
---
This patch looks if ActionDispatch's request normalization is loaded,
and if so, uses it to normalize the path before processing throttles,
blacklists, etc.
If it's not loaded, the request path is not modified.
Credit
---
Thanks to Andres Riancho at Include Security for reporting this issue.
I need to filter requests on a period I need to get dynamically out of
information I have in the requests. Currently, I can work out the limit,
as it can be a `Proc`, however I can't do that with the period.
This PR adds support for that. Tried to do it in a way that doesn't
brake backwards compatibility, as periods are coerced to numbers during
`Rack::Throttle` initialization.
For throttling, when the redis client throws an exception, the request
ends up getting rate limited. Modify this to be similar to how
ActiveSupport.MemCacheStore functions (the read, write and increment
methods do not raise exceptions)
401 Unauthorized suggests that the requests can be
retried with appropriate credentials. 403 explicitly
states that the request should not be repeated.
See #41
An alternate to fail2ban that allows clients until they hit the
thresholds, then blocks them. Think of it like a throttle where you can
block for more than one period.
Throttles use a cache key with a timestamp (Time.now.to_i/period), so a
new cache key is used for each period.
No longer set an explicit expiry on each cache key (though it may
inherit a default expiry from the cache store).
Also, set env['rack.attack.throttle_data'] with info about incremented
(but not necessarily exceeded) throttles.
