Subject: [quicwg/base-drafts] Don't amplify 0-RTT (#1616)

From: Martin Thomson <[email-masked]>
Date: Mon, 30 Jul 2018 22:06:41 -0700

No concrete recommendations, though it seems like kInitialWindow (which
caps at 14600) is probably a good backstop.  It might even be a good
recommendation, but I don't think that we need to concern ourselves with
finding a specific value in the same way we have for the handshake.

Closes #1309.
You can view, comment on, or merge this pull request online at:

  https://github.com/quicwg/base-drafts/pull/1616

-- Commit Summary --

  * Don't amplify 0-RTT

-- File Changes --

    M draft-ietf-quic-transport.md (7)

-- Patch Links --

https://github.com/quicwg/base-drafts/pull/1616.patch
https://github.com/quicwg/base-drafts/pull/1616.diff

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From: ekr <[email-masked]>
Date: Tue, 31 Jul 2018 19:43:28 -0700

ekr requested changes on this pull request.

> @@ -1896,6 +1896,13 @@ dynamically calculate the expiration time.  It is also unlikely that the client
 port number is the same on two different connections; validating the port is
 therefore unlikely to be successful.
 
+Even when a token is valid, a server SHOULD limit the amount of data that it
+sends toward a client in response to 0-RTT data.  Spoofing of source addresses
+and replays of 0-RTT handshake messages can cause tokens to appear to be valid
+when they are not.  No specific recommendation is made regarding the ratio of
+data sent to received, though it is unlikely to be necessary to send more than
+the initial congestion window.

This text seems wrong. Tokens are either valid or they are not.

What specific attack scenario are you concerned with?

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From: Martin Thomson <[email-masked]>
Date: Tue, 31 Jul 2018 23:26:04 -0700

martinthomson commented on this pull request.

Tokens might be ignored (as we discussed, they might be old, or the keys might not be available).

This is your issue #1309.

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