Comment by mcintyre1994
8 years ago
I'm not sure if you've had a chance to look at the Cloudflare blog post yet (https://blog.cloudflare.com/incident-report-on-memory-leak-c...), but while they take full responsibility they do point out (under root cause of the bug) that a generated equality check could be >= instead which would avoid the bug. Obviously GIGO applies and it's their bug, but it might be worth seeing if there's anything you can do on Ragel side?
Well doing that would mean ragel would incorrectly read one character, rather than run off forever. Personally I'd rather have the latter. Much easier to catch with memory checkers. Eventually you try to read some thing you're not allowed to read, or blow something else up, instead of just read the first byte of the int following the buffer, or whatever.
There would have to be an additional bounds check when issuing a goto in an error action, but doing that is contrary to the simple execution model that ragel users have come to rely on.
Gotta ask the question, where was the testing when they altered 7 year old code without the involvement of the original developer?