Re: [netconf] [Technical Errata Reported] RFC8040 (7866)

[Jernej Tuljak <[e-mail]>]

On 03/04/2024 18:55, Andy Bierman wrote:
>
>
> On Wed, Apr 3, 2024 at 6:16 AM Jernej Tuljak 
> <[e-mail]> wrote:
>
>     On 29/03/2024 17:09, Andy Bierman wrote:
>>
>>
>>     On Fri, Mar 29, 2024 at 12:46 AM Jernej Tuljak
>>     <[e-mail]> wrote:
>>
>>         On 28/03/2024 17:25, Andy Bierman wrote:
>>>
>>>
>>>         On Thu, Mar 28, 2024 at 2:41 AM Jernej Tuljak
>>>         <[e-mail]> wrote:
>>>
>>>             And I'm still not sure why RFC8040 refers to "reserved
>>>             characters" as
>>>             the only characters that need to be percent-encoded.
>>>
>>>             Section 2.1 of RFC3986 that describes percent encoding says:
>>>
>>>                 A percent-encoding mechanism is used to represent a
>>>             data octet in a
>>>                 component when that octet's corresponding character
>>>             is outside the
>>>                 allowed set or is being used as a delimiter of, or
>>>             within, the
>>>                 component.
>>>
>>>             Then in 2.2 it says:
>>>
>>>                 URIs include components and subcomponents that are
>>>             delimited by
>>>                 characters in the "reserved" set. These characters
>>>             are called
>>>                 "reserved" because they may (or may not) be defined
>>>             as delimiters by
>>>                 the generic syntax, by each scheme-specific syntax,
>>>             or by the
>>>                 implementation-specific syntax of a URI's
>>>             dereferencing algorithm.
>>>
>>>             To me this means there's more than just what RFC3986
>>>             considers to be a
>>>             "reserved character" that should to be percent-encoded.
>>>             The "more" in
>>>             this case being characters "outside the allowed set".
>>>             Characters like
>>>             the double-quote, which I've brought up before, but
>>>             never got a response:
>>>
>>>
>>>
>>>         The part of sec. 2.2 that was left out lists the chars:
>>>
>>>                reserved    = gen-delims / sub-delims
>>>
>>>                gen-delims  = ":" / "/" / "?" / "#" / "[" / "]" / "@"
>>>
>>>                sub-delims  = "!" / "$" / "&" / "'" / "(" / ")"
>>>                            / "*" / "+" / "," / ";" / "="
>>>
>>>         IMO these chars need to be percent-encoded in RESTCONF URIs
>>>
>>>             https://mailarchive.ietf.org/arch/msg/netconf/I8kXANHiqeV2JsCWmtTE2fGjYd8/
>>>
>>>
>>>
>>>         Perhaps there are some details that are not spelled out.
>>>         Double-quote and space are not special in RESTCONF.
>>>
>>
>>         Are you saying that valid RESTCONF URIs are not required to
>>         be valid RFC3986 URIs?
>>
>>
>>     No, I am saying that if restconf-next ever happens, then the
>>     document can clarify any additional
>>     reserved characters.
>
>     You said that double-quote and space are not special in RESTCONF,
>     but how can that be true, when they are special in RFC3986? What
>     makes them special is that they are not allowed at all. Anywhere.
>     No production of RFC3986 ABNF grammar [1] can match them. So they
>     need to be percent-encoded. They do not represent reserved
>     characters but at the same time cannot be recognized as unreserved
>     characters.
>
>
>
> I meant no special meaning in RESTCONF.
> RFC 3986 defines the URI encoding.
> There is no intent for RESTCONF to change anything or cherry-pick 
> certain requirements and ignore others.
>
> I am not sure what document changes are needed. Perhaps none.

I have a specific change in mind.

RFC8040, Section 3.5.3.:

OLD:

    The following example shows how reserved characters are
    percent-encoded within a key value.  The value of "key1" contains
    a comma, single-quote, double-quote, colon, double-quote, space,
    and forward slash (,'":" /).  Note that double-quote is not a
    reserved character and does not need to be percent-encoded.  The
    value of "key2" is the empty string, and the value of "key3" is the
    string "foo".

    Example URL:

       /restconf/data/example-top:top/list1=%2C%27"%3A"%20%2F,,foo

NEW:

    The following example shows how specific characters are
    percent-encoded within a key value.  The value of "key1" contains
    a comma, single-quote, double-quote, colon, double-quote, space,
    and forward slash (,'":" /).  Note that double-quote and space are
    not reserved characters but also do not correspond to characters in
    the unreserved set and therefore need to be percent-encoded.  The
    value of "key2" is the empty string, and the value of "key3" is the
    string "foo".

    Example URL:

/restconf/data/example-top:top/list1=%2C%27%22%3A%22%20%2F,,foo


Or something along those lines. It seemed related to this errata (7866), 
which is why I brought it up again.

Jernej

> Perhaps hold for document update.
>
>     [1] - https://datatracker.ietf.org/doc/html/rfc3986#appendix-A
>
>     Jernej
>
>
>
> Andy
>
>
>>
>>         Jernej
>>
>>
>>     Andy
>>
>>
>>>         One thing that is clear:
>>>         Any user of a RESTCONF URI MUST be capable of converting
>>>         percent-encoded chars,
>>>         no matter what they are.
>>>
>>>
>>>
>>>
>>>             Jernej
>>>
>>>
>>>         Andy
>>>
>>>
>>>             On 27/03/2024 16:54, Kent Watsen wrote:
>>>             > This errata is incomplete.
>>>             > The issue occurs three times.
>>>             > The occurrence in Section 5.1 is missing.
>>>             >
>>>             > K.
>>>             >
>>>             >
>>>             >> On Mar 23, 2024, at 1:38 PM, RFC Errata System
>>>             <[e-mail]> wrote:
>>>             >>
>>>             >> The following errata report has been submitted for
>>>             RFC8040,
>>>             >> "RESTCONF Protocol".
>>>             >>
>>>             >> --------------------------------------
>>>             >> You may review the report below and at:
>>>             >> https://www.rfc-editor.org/errata/eid7866
>>>             >>
>>>             >> --------------------------------------
>>>             >> Type: Technical
>>>             >> Reported by: Andy Bierman <[e-mail]>
>>>             >>
>>>             >> Section: 3.5.3
>>>             >>
>>>             >> Original Text
>>>             >> -------------
>>>             >> Text occurs in two places
>>>             >>
>>>             >> 1)
>>>             >>
>>>             >>       The leaf-list value is specified as a string,
>>>             using the canonical
>>>             >>       representation for the YANG data type.  Any
>>>             reserved characters
>>>             >>       MUST be percent-encoded, according to Sections
>>>             2.1 and 2.5 of
>>>             >>       [RFC3986].
>>>             >>
>>>             >>
>>>             >> 2)
>>>             >>
>>>             >>       The key value is specified as a string, using
>>>             the canonical
>>>             >>       representation for the YANG data type.  Any
>>>             reserved characters
>>>             >>       MUST be percent-encoded, according to Sections
>>>             2.1 and 2.5 of
>>>             >>       [RFC3986].
>>>             >>
>>>             >>
>>>             >> Corrected Text
>>>             >> --------------
>>>             >>
>>>             >> 1)
>>>             >>
>>>             >>       The leaf-list value is specified as a string,
>>>             using the canonical
>>>             >>       representation for the YANG data type.  Any
>>>             reserved characters
>>>             >>       MUST be percent-encoded, according to Sections
>>>             2.1, 2.2, and 2.5 of
>>>             >>       [RFC3986].
>>>             >>
>>>             >> 2)
>>>             >>
>>>             >>       The key value is specified as a string, using
>>>             the canonical
>>>             >>       representation for the YANG data type.  Any
>>>             reserved characters
>>>             >>       MUST be percent-encoded, according to Sections
>>>             2.1, 2.2, and 2.5 of
>>>             >>       [RFC3986].
>>>             >>
>>>             >>
>>>             >> Notes
>>>             >> -----
>>>             >> The reserved character list is defined in section 2.2
>>>             of RFC 3986
>>>             >>
>>>             >> Instructions:
>>>             >> -------------
>>>             >> This erratum is currently posted as "Reported". (If
>>>             it is spam, it
>>>             >> will be removed shortly by the RFC Production
>>>             Center.) Please
>>>             >> use "Reply All" to discuss whether it should be
>>>             verified or
>>>             >> rejected. When a decision is reached, the verifying party
>>>             >> will log in to change the status and edit the report,
>>>             if necessary.
>>>             >>
>>>             >> --------------------------------------
>>>             >> RFC8040 (draft-ietf-netconf-restconf-18)
>>>             >> --------------------------------------
>>>             >> Title               : RESTCONF Protocol
>>>             >> Publication Date    : January 2017
>>>             >> Author(s)           : A. Bierman, M. Bjorklund, K. Watsen
>>>             >> Category            : PROPOSED STANDARD
>>>             >> Source              : Network Configuration
>>>             >> Stream              : IETF
>>>             >> Verifying Party     : IESG
>>>             > _______________________________________________
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>>>
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>>
>