Re: PROBLEM: DoS Attack on Fragment Cache

From: Willy Tarreau
Date: Sat Apr 17 2021 - 03:50:51 EST

On Sat, Apr 17, 2021 at 12:42:39AM -0700, Keyu Man wrote:
> How about at least allow the existing queue to finish? Currently a tiny new
> fragment would potentially invalid all previous fragments by letting them
> timeout without allowing the fragments to come in to finish the assembly.

Because this is exactly the principle of how attacks are built: reserve
resources claiming that you'll send everything so that others can't make
use of the resources that are reserved to you. The best solution precisely
is *not* to wait for anyone to finish, hence *not* to reserve valuable
resources that are unusuable by others.