Re: [Uri-review] Proposed scheme registration: sdns (DNS stamps)

Eric Johnson <eric@tibco.com> Thu, 25 October 2018 00:49 UTC

Return-Path: <eric@tibco.com>
X-Original-To: uri-review@ietfa.amsl.com
Delivered-To: uri-review@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id C01E5130DD5 for <uri-review@ietfa.amsl.com>; Wed, 24 Oct 2018 17:49:32 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.999
X-Spam-Level:
X-Spam-Status: No, score=-1.999 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=unavailable autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (1024-bit key) header.d=tibco.com
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id rOIBfOWZlJmC for <uri-review@ietfa.amsl.com>; Wed, 24 Oct 2018 17:49:28 -0700 (PDT)
Received: from mail-lf1-x12a.google.com (mail-lf1-x12a.google.com [IPv6:2a00:1450:4864:20::12a]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 9DF23130DCC for <uri-review@ietf.org>; Wed, 24 Oct 2018 17:49:27 -0700 (PDT)
Received: by mail-lf1-x12a.google.com with SMTP id n3-v6so5422955lfe.7 for <uri-review@ietf.org>; Wed, 24 Oct 2018 17:49:27 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tibco.com; s=tibcogoogle; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=y45yvDiGpziX5N3TXSTLzn/gIsaY6W+yvYinJAANp6s=; b=duKYCD24qsgZhw09RipTInbvsa81HB13CuJHuyDcL6GLjYo1aaQEwS7g05Ju4GrHBC +ebcQPbCAcHyWabTApc992R2LjblBNA5ooRvDP2ujFXYRt4JzNo/xzz/JKAE8GT0hcz4 1ND1QVzMu3GbHBCGyNXoO9iQdZJbNIT2HyLn0=
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=y45yvDiGpziX5N3TXSTLzn/gIsaY6W+yvYinJAANp6s=; b=uVDpjFpX88FuA11kAIxdn+Z2g4ggBqOk/DUCVUo+ZyyHbF9cn2JCk0xLXTY8hDp0M0 2aQM4D8KQ7yXxh2ia8seOhdUkbw4HeIqxMrdsN/8E0kNS3rZCbaB5dFmUapt6rnVOdSj 6OkAznX41jwOS1tItnrECOhwO93YbbOrWZQUHfWSNJCGItNEsKN+iRoSy5gHcD8+zvJ8 SkJRbBbkw6rwMvrzMud+0VTopDCJUNZ506m7DV2k7UQtB/oDe4mZcIuV224Gw9w2BRhC bA9i243ufA1TXPsUA7RNTnd0ySJ0aH5pMSDJgZnIKCB93kZfBa0jgTO2I+9BFOBkblV6 n0Zg==
X-Gm-Message-State: AGRZ1gKvGMuaSMtDNsw08JSFQzzo2U3eljKidLhkmi7ESIAJaXoyPMop aEqTEw8d6mmsu0uRoAA4ldOmLsfC4SeR14Hp9MSL
X-Google-Smtp-Source: AJdET5fWGGbfWew/kORJgDyIqUUDJmVTGdUNwB/0oHEy55DJHVbAxiLTnA+22rW4H1YNKv4YfCJ6TjzLrwaCzVJSCMg=
X-Received: by 2002:a19:1365:: with SMTP id j98mr278098lfi.55.1540428565587; Wed, 24 Oct 2018 17:49:25 -0700 (PDT)
MIME-Version: 1.0
References: <20181024155855.4v4s4lwov4luufrs@msync.c9x.org> <CA+9kkMAwX1uDguV43MgNbHdz8MyEE-kDa2+k=JmVFas+6=7p8A@mail.gmail.com> <3D3389E3-292A-408E-9204-B8C3E47BD3F3@dnscrypt.info>
In-Reply-To: <3D3389E3-292A-408E-9204-B8C3E47BD3F3@dnscrypt.info>
From: Eric Johnson <eric@tibco.com>
Date: Wed, 24 Oct 2018 17:49:14 -0700
Message-ID: <CANu9=Nc0R0++sZDAhUF7y=2tM=+xU83OPOv5vDkOgoehVPXCaQ@mail.gmail.com>
To: ietf=40dnscrypt.info@dmarc.ietf.org
Cc: ted.ietf@gmail.com, uri-review@ietf.org
Content-Type: multipart/alternative; boundary="000000000000744562057902f956"
Archived-At: <https://mailarchive.ietf.org/arch/msg/uri-review/u1T5816ZOCdsZD_rzMQ2Z6c2TKw>
Subject: Re: [Uri-review] Proposed scheme registration: sdns (DNS stamps)
X-BeenThere: uri-review@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Proposed URI Schemes <uri-review.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/uri-review>, <mailto:uri-review-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/uri-review/>
List-Post: <mailto:uri-review@ietf.org>
List-Help: <mailto:uri-review-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/uri-review>, <mailto:uri-review-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 25 Oct 2018 00:49:33 -0000

I don't typically chime in on these proposals much, but this one strikes me
as odd. I don't understand the point of having a string representation if
the entirety of the string - except the leading scheme name - is base 64
encoded. Well, OK, I get it for a URI scheme where the underlying data is
actually binary, such as the "data" scheme, except even with that, the
"media-type" is not base64 encoded. This scheme doesn't seem to fit that
model.

The previous comment about the "//" is correct. This is *not* a
hierarchical scheme, so it should not have a "//". That is, "../foobar" is
a meaningless relative URI to apply to the proposed sdns scheme.

I took a random example from
https://github.com/DNSCrypt/dnscrypt-resolvers/blob/master/v2/public-resolvers.md

sdns://AgMAAAAAAAAADDM1LjIzMS42OS43NyA-GhoPbFPz6XpJLVcIS1uYBwWe4FerFQWHb9g_2j24OBJkbnMtZ2NwLmFhZmxhbG8ubWUKL2Rucy1xdWVyeQ

When this is expanded, based on the demo <https://dnscrypt.info/stamps/>;, I
find that this is:
protocol: DNS-over-HTTP/2
IP:35.231.69.77
host-name: dns-gcp.aaflalo.me
DNSSEC: true
No logs: true
No filter: false
Hashes: 3e1a1a0f6c53f3e97a492d57084b5b9807059ee057ab1505876fd83fda3db838
Makes me wonder why this can't just be represented as:

sdns:dns-over-http2:ip-35.231.69.77:hn-dns-gcp.aaflolo.me:
dnssec:nologs:hashes-3e1a1a0f6c53f3e97a492d57084b5b9807059ee057ab1505876fd83fda3db838

Maybe I don't understand all the design parameters behind the original
proposal? My proposed above form has a whole bunch of up-sides. It is easy
to visually inspect for certain aspects of correctness, it is more robust
in the face of future enhancements, and it is order-insensitive. Maybe my
idea is completely off base, in which case, it would be very helpful to
augment the proposed specification to clarify why the current proposed
opaque form is *required*.

If compatibility with existing tools is required, then there are multiple
paths:
- check for hierarchy use in existing implementions (sdns:// parsed
differently from sdns:...)
- register a under a new scheme, and phase out support for the existing
sdns:// uses

Eric.


On Wed, Oct 24, 2018 at 10:12 AM Frank Denis <ietf=
40dnscrypt.info@dmarc.ietf.org>; wrote:

>
> > On 24 Oct 2018, at 18:31, Ted Hardie <ted.ietf@gmail.com>; wrote:
> >
> > Hi Frank,
>
>   Hi Ted,
>
>
> > Thanks for sending the proposal to the list.  A couple of high level
> comments.
> >
> > First, the syntax you present uses //, which doesn't seem to be correct
> to me.  If I'm reading the specification correctly, the URL doesn't have a
> hierarchical part and does not rely on an authority section (which is what
> the // delimits in RFC 3986 syntax).
>
>   All the sdns URIs currently in use share a global namespace. However,
> the parameters specifically use URL-safe base64 to avoid slashes, so URIs
> can later:
>
> - Support namespaces
> - Support implementation-specific filters (e.g. `sdns://.../ipv6only)
>
>
> > 2nd, it's not clear in the description of addresses how they would be
> fed into the algorithm you provide in some of the corner cases.  For
> example:
> > "addr is the IP address of the server. It can be an empty string, or
> just a port number."  Is the port number represented with a preceding
> colon?
>
>   A preceding colon is required. The description has been updated to
> clarify this. Thanks!
>
>
> > For IPv6 hosts which use [ and ] as delimeters, is the input URL-encoded
> before being base64 encoded?  Are scopes permitted?
>
>   Scopes are permitted, and are supported by current implementations. The
> document has been updated to reflect this.
>
>   Strings are not encoded individually, besides being preceded by their
> length.
>
>   The entire concatenation of all parameters is eventually base64-encoded.
> The document has been updated to clarify this.
>
>
> > For hostname, the document says  that hostname is the server host name
> which will also be used as a SNI name.  If the hostname uses one of the
> IDNA characters outside the URL-permitted range, is it encoded with URL
> encoding or punycode?
>
>   SNI names in certificates are raw binary strings. Given the context, we
> probably shouldn’t apply any encoding either. The document has been updated
> to clarify this.
>
>
> > As a stylistic note, I think sdns is likely to be confused with the
> existing dns scheme name, and I would suggest using "dns-stamps" for
> additional clarity.
>
>   This is definitely doable, but would be break all existing
> implementations and servers lists,
>
>
> > Thanks again for the opportunity to comment,
>
>   Thanks for your very helpful comments, Ted.
>
>
> _______________________________________________
> Uri-review mailing list
> Uri-review@ietf.org
> https://www.ietf.org/mailman/listinfo/uri-review
>