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Re: [quicwg/base-drafts] The QUIC-TLS draft should define anti-forgery limits for packet lengths up to 2^16 (#3701)

ekr <notifications@github.com> Fri, 25 September 2020 04:10 UTC

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Date: Thu, 24 Sep 2020 21:10:13 -0700
From: ekr <notifications@github.com>
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Subject: Re: [quicwg/base-drafts] The QUIC-TLS draft should define anti-forgery limits for packet lengths up to 2^16 (#3701)
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I had forgotten about this parameter. I don't think we even need an extension. We say:

> You MUST NOT send max_udp_payload_size > 16384. If you receive max_udp_payload_size > 16384 you MUST treat it as 16384.

Then if we figure out new anti-forgery limits we remove these MUSTs.

Only new implementations will send max_udp_payload_size > 16384 and only if both implementations are new will they send packets > 16384. That means that (1) sending implementations will enforce the right AEAD limits (2) only implementations which know about the new limits will offer max_udp_payload_size > 16384 and they can just reject longer packets out of hand which means that they don't contribute to the forgery limit.




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