Re: [quicwg/base-drafts] clarify the scope of a NEW_TOKEN token (#3156)

Martin Thomson <> Mon, 28 October 2019 09:32 UTC

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From: Martin Thomson <>
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Subject: Re: [quicwg/base-drafts] clarify the scope of a NEW_TOKEN token (#3156)
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martinthomson commented on this pull request.

> @@ -1698,10 +1698,14 @@ encrypted form in the token.
 It is unlikely that the client port number is the same on two different
 connections; validating the port is therefore unlikely to be successful.
-If the client has a token received in a NEW_TOKEN frame on a previous connection
-to what it believes to be the same server, it SHOULD include that value in the
-Token field of its Initial packet.  Including a token might allow the server to
-validate the client address without an additional round trip.
+A token received in a NEW_TOKEN frame is applicable against the servers that the
+connection is considered authoritative for (e.g., server names included in the
+certificate).  A client MUST only use a token that is applicable to the server

I don't remember making that argument, but I guess I could have said that.

The particular "attack" requires having a server privileged or capable enough to recognize a token from a different server with a fair degree of confidence.  For NEW_TOKEN, I can maybe see how that would happen though.  I'm OK with a MUST.

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