Differential D17758
Update rate limiting for APCu and X-Forwarded-For Authored by epriestley on Apr 21 2017, 8:59 PM. Tags None Referenced Files
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Details Ref T12612. This updates the rate limiting code to:
I'm planning to put this into production on secure for now and then we can deploy it more broadly if things work well.
Diff Detail
Event TimelineComment Actions Obligatory "but how much traffic can the rate-limiting infrastructure handle before that itself triggers a DoS condition?" comment, even though I'm sure APCu can handle it.
Comment Actions I see some weird PHP 7.1 / APCu interaction locally so this may only be in the ballpark of how things will work in production, but ab -n 1000 can legitimately burn through 1K requests serially in ~200ms: $ ab -n 1000 http://local.phacility.com/ This is ApacheBench, Version 2.3 <$Revision: 1757674 $> Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/ Licensed to The Apache Software Foundation, http://www.apache.org/ Benchmarking local.phacility.com (be patient) Completed 100 requests Completed 200 requests Completed 300 requests Completed 400 requests Completed 500 requests Completed 600 requests Completed 700 requests Completed 800 requests Completed 900 requests Completed 1000 requests Finished 1000 requests Server Software: Apache/2.4.16 Server Hostname: local.phacility.com Server Port: 80 Document Path: / Document Length: 73 bytes Concurrency Level: 1 Time taken for tests: 0.222 seconds Complete requests: 1000 Failed requests: 0 Non-2xx responses: 1000 Total transferred: 285000 bytes HTML transferred: 73000 bytes Requests per second: 4507.83 [#/sec] (mean) Time per request: 0.222 [ms] (mean) Time per request: 0.222 [ms] (mean, across all concurrent requests) Transfer rate: 1254.62 [Kbytes/sec] received Connection Times (ms) min mean[+/-sd] median max Connect: 0 0 0.0 0 0 Processing: 0 0 0.0 0 0 Waiting: 0 0 0.0 0 0 Total: 0 0 0.0 0 1 Percentage of the requests served within a certain time (ms) 50% 0 66% 0 75% 0 80% 0 90% 0 95% 0 98% 0 99% 0 100% 1 (longest request) So I think the cost of this is low enough to handle any reasonable non-attack traffic. If we're actually seeing attack traffic which can overwhelm this, I think the next step would be to try to block it in the VPC ACL? As far as I can tell, there's no way to block traffic from ELBs / ALBs, although maybe I'm just not looking in the right place. | ||||||||||||||||||||||||||||||||||