Moving to a three-byte length wouldn't do anything: extension bodies themselves have two-byte lengths, so any longer lengths within an extension is just a waste.
(To that end, because every field in a ClientHello has a two-byte length, the longest possible syntactically valid ClientHello at all is 2 + 32 + 32 + 1 + 32 + 2 + 2^16-2 + 1 + 2^8-1 + 2 + 2^16 - 1 bytes, which is doesn't fit in two-byte length, but nearly does. And, in practice, implementations may impose length limits on incoming messages beyond that to avoid DoS risks.) On Sat, Feb 20, 2021 at 3:19 PM Stephen Farrell <stephen.farr...@cs.tcd.ie> wrote: > > Hiya, > > The CH in TLS has a 3 octet length. The payload in ECH has a > 2-octet length. Hopefully that'll never matter but it's an > inconsistency I don't recall coming up before. (Apologies if > I've forgotten, or if I've missed something in 8446 that > forbids bigger CH's.) > > I'm fine with just leaving it as-is, or with noting in the > text that you will suffer this problem (and many others;-) if > you want to use a CH that's that long, or with moving to a 3 > octet length for the payload. > > Cheers, > S. > _______________________________________________ > TLS mailing list > TLS@ietf.org > https://www.ietf.org/mailman/listinfo/tls >
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