Re: [TLS] draft-ietf-tls-esni feedback

Eric Rescorla <ekr@rtfm.com> Mon, 21 October 2019 16:45 UTC

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From: Eric Rescorla <ekr@rtfm.com>
Date: Mon, 21 Oct 2019 09:44:24 -0700
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To: Rob Sayre <sayrer@gmail.com>
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Subject: Re: [TLS] draft-ietf-tls-esni feedback
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On Mon, Oct 21, 2019 at 7:56 AM Rob Sayre <sayrer@gmail.com>; wrote:

> On Mon, Oct 21, 2019 at 7:41 AM Eric Rescorla <ekr@rtfm.com>; wrote:
>
>>
>>
>> On Mon, Oct 21, 2019 at 7:32 AM Rob Sayre <sayrer@gmail.com>; wrote:
>>
>>
>>
>>> Judging by the mailing list archives, the design of the field is
>>>>> intentional. It's not clear to me why "zeros" wasn't specified as
>>>>> variable-length with a prose restriction, though.
>>>>>
>>>>
>>>> Because then you have a spurious length field.
>>>>
>>>
>>> I don't understand why it would be spurious. In this case, the
>>> deserializing implementation needs to inspect every byte anyway.
>>>
>>
>> Because if you set padding to be the length of the maximum value, then a
>> length byte makes every message one longer.
>>
>
> Sorry if I'm being dense here. Couldn't "zeros" have a length? Maybe you
> just mean it would be superfluous.
>

Yes, that is what I mean.

-Ekr