> It's my understanding that random padding doesn't in fact make the attacker's job "much more" difficult. Only a little more, or not at all?
The BREACH attack verbage at http://breachattack.com spells it out fairly clearly, by adding random bytes to all of the HTTP responses, it makes small compressed HTTP payloads impossible to determine whether guessed bytes were correct or not (well, depending of course on the size variable of the random bytes added).
> Could you comment on how integrated the TLS stack is with the webserver?
The TLS layer is entirely separate from the webserver layer. I built the epoll, TLS, SSH, webserver and client as "IO layers", such that they can be stacked together arbitrarily (imagine epoll/IPv4 listener -> TLS -> SSH -> TLS -> Webserver, perfectly doable, albeit a little nutty).
> it makes small compressed HTTP payloads impossible to determine whether guessed bytes were correct or not (well, depending of course on the size variable of the random bytes added).
Hm, ok. At least you didn't "just add some random padding" :-)
Thanks for the comment on structure. Might be nice to try and make ssl/tls terminating proxy as a separate binary I guess.
As for the code, for someone new to fasm it wasn't immediately obvious that to build one had to assemble then link (fasm -m $((bignumber))[1] project.asm project.o && ld -o project project.o # optionally strip project). Might want to but that in a Readme/makefile/build.sh. I found the general recipe in the hello-example - but a short readme in the various project folder and/or top level wouldn't hurt.
> I built the epoll, TLS, SSH, webserver and client as "IO layers"
I think you should just finish the job and implement the entire OS in assembly. ;-)
I'm kidding. To me, assembly programming has always seemed like a true art form. You're forced to think about everything, and if you can successfully fit all the pieces together properly, it's beautiful. Also, not many can hack it through assembly, so there's a huge selection bias too.
The BREACH attack verbage at http://breachattack.com spells it out fairly clearly, by adding random bytes to all of the HTTP responses, it makes small compressed HTTP payloads impossible to determine whether guessed bytes were correct or not (well, depending of course on the size variable of the random bytes added).
> Could you comment on how integrated the TLS stack is with the webserver?
The TLS layer is entirely separate from the webserver layer. I built the epoll, TLS, SSH, webserver and client as "IO layers", such that they can be stacked together arbitrarily (imagine epoll/IPv4 listener -> TLS -> SSH -> TLS -> Webserver, perfectly doable, albeit a little nutty).