Subject: [quicwg/base-drafts] 8d15c9: 3x amplification limit for CONNECTION_CLOSE

From: Martin Thomson <[email-masked]>
Date: Tue, 07 Jul 2020 22:53:18 -0700

Branch: refs/heads/close-amplification
  Home:   https://github.com/quicwg/base-drafts
  Commit: 8d15c9b4a61a391541b7344166cb60f431bca1a0
      https://github.com/quicwg/base-drafts/commit/8d15c9b4a61a391541b7344166cb60f431bca1a0
  Author: Martin Thomson <[email-masked]>
  Date:   2020-07-08 (Wed, 08 Jul 2020)

  Changed paths:
    M draft-ietf-quic-transport.md

  Log Message:
  -----------
  3x amplification limit for CONNECTION_CLOSE

We weren't very concrete in saying how endpoints generate packets with
CONNECTION_CLOSE, particularly those that throw away keys.  We have
a rather vague requirement.

In short, follow the same rules we established for the handshake.
Wording this as an aggregate number allows for stochastic reactions and
larger CONNECTION_CLOSE frames.  This way, if you get a 25-byte packet
and respond with a 200-byte packet, you can do that, but you have to
respond to 3 in 8 or fewer in that way.

Note that this limit only applies if the endpoint throws away decryption
keys.  Endpoints with keys aren't blind amplifiers.

Closes #3845.