Re: [DNSOP] SVCB ALPN value presentation format

Ben Schwartz <bemasc@google.com> Sat, 13 June 2020 15:25 UTC

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From: Ben Schwartz <bemasc@google.com>
Date: Sat, 13 Jun 2020 11:25:04 -0400
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To: Larry Campbell <lcampbel=40akamai.com@dmarc.ietf.org>
Cc: dnsop <dnsop@ietf.org>
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Subject: Re: [DNSOP] SVCB ALPN value presentation format
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Larry,

I think that's the intent of the current text, especially the ABNF for
"element".  If you think it's unclear, we should adjust it.  Please suggest
text!

--Ben Schwartz

On Sat, Jun 13, 2020, 10:53 AM Larry Campbell <lcampbel=
40akamai.com@dmarc.ietf.org> wrote:

> Seciont 6.1 says:
>
> > The presentation value of "alpn" is a comma-separated list of one or
> more "alpn-id"s. Any commas present in the protocol-id are escaped by a
> backslash:
> >
> >     escaped-octet = %x00-2b / "\," / %x2d-5b / "\\" / %x5D-FF
> >     escaped-id = 1*(escaped-octet)
> >     alpn-value = escaped-id *("," escaped-id)
>
> If I read this correctly, the presentation value is allowed to contain
> nulls and control characters. This seems likely to make such records very
> difficult to edit. Wouldn't it be better to require these to be encoded as
> \nnn?
>
> - lc
>
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