Re: [http-state] Is this an omission in the parser rules of draft-ietf-httpstate-cookie-21?

Adam Barth <ietf@adambarth.com> Mon, 14 February 2011 23:43 UTC

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From: Adam Barth <ietf@adambarth.com>
Date: Mon, 14 Feb 2011 15:43:04 -0800
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To: Peter Saint-Andre <stpeter@stpeter.im>
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Subject: Re: [http-state] Is this an omission in the parser rules of draft-ietf-httpstate-cookie-21?
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On Mon, Feb 14, 2011 at 3:41 PM, Peter Saint-Andre <stpeter@stpeter.im>; wrote:
> On 2/10/11 6:09 PM, Adam Barth wrote:
>> On Thu, Feb 10, 2011 at 4:59 PM, Peter Saint-Andre <stpeter@stpeter.im>; wrote:
>>> On 2/4/11 12:29 PM, Adam Barth wrote:
>>>> On Fri, Feb 4, 2011 at 11:24 AM, Roy T. Fielding <fielding@gbiv.com>; wrote:
>>>>> On Feb 4, 2011, at 10:51 AM, Adam Barth wrote:
>>>>>> On Fri, Feb 4, 2011 at 10:47 AM, Remy Lebeau <remy@lebeausoftware.org>; wrote:
>>>>>>> -------- Original Message --------
>>>>>>> Subject: Re: [http-state] Is this an omission in the parser rules of
>>>>>>> draft-ietf-httpstate-cookie-21?
>>>>>>> From: Adam Barth
>>>>>>> Date: Fri, February 04, 2011 10:19 am
>>>>>>> To: Remy Lebeau
>>>>>>> Cc: http-state@ietf.org
>>>>>>>
>>>>>>>> The draft gives user agents precise
>>>>>>>> instructions for how to parse all
>>>>>>>> manner of cookies, including cookies with
>>>>>>>> values that contain quote characters. That
>>>>>>>> information is contained in Section 5
>>>>>>>
>>>>>>> I have re-read Section 5 and I do not see its grammar or parsing rules
>>>>>>> accounting for quoted-string values at all. It only says to remove WSP
>>>>>>> characters surrounding extracted names and values, and quote characters
>>>>>>> are not part of the WSP definition. So what am I missing? Where exactly
>>>>>>> does it say how to unquote a quoted-string used in attribute values?
>>>>>>
>>>>>> Precisely.  It does not say to unquote a quoted-string because that's
>>>>>> not how cookies work.  The role of the quote character is cookies is
>>>>>> identical to the role of the "!" character.  That is, neither play a
>>>>>> special role in the protocol.  Any representations by the contrary by
>>>>>> 2109 or any other document are fiction and have only caused pain and
>>>>>> misery in the world.
>>>>>
>>>>> That may be, but the grammar for server generation of set-cookie
>>>>> values is clearly wrong because use of DQUOTE in cookie values is
>>>>> common (roughly 10% of the values in my browser cookie store) and
>>>>> previously defined, even if we consider DQUOTE to be part of the
>>>>> value string.  Let's just change the generating grammar for value to
>>>>> match how cookies are actually parsed and only exclude characters
>>>>> that are known to cause failures.
>>>>
>>>> The grammar is not used for parsing.  Parsing is defined in Section 5,
>>>> not Section 4.
>>>
>>> Right. And I think the revised text in version -21 (with revisions to
>>> address the IESG comment from Robert Sparks) makes that fairly clear.
>>>
>>> Adam, did you propose specific text addressing Dan Winship's original
>>> issue about "cookie-value=token"? As far as I can see, that's the only
>>> substantive issue raised in this thread, but I admit that I might have
>>> missed something.
>>
>> Sure:
>>
>> diff --git a/drafts/cookie.xml b/drafts/cookie.xml
>> index e0a53f3..17cc0a5 100644
>> --- a/drafts/cookie.xml
>> +++ b/drafts/cookie.xml
>> @@ -335,7 +335,8 @@ set-cookie-header = "Set-Cookie:" SP set-cookie-string
>>  set-cookie-string = cookie-pair *( ";" SP cookie-av )
>>  cookie-pair       = cookie-name "=" cookie-value
>>  cookie-name       = token
>> -cookie-value      = token / ""
>> +cookie-value      = token / *base64-character
>> +base64-character  = ALPHA / DIGIT / "+" / "/" / "="
>>  token             = <token, defined in [RFC2616], Section 2.2>
>>
>>  cookie-av         = expires-av / max-age-av / domain-av /
>> @@ -370,7 +371,7 @@ extension-av      = <any CHAR except CTLs or ";">
>>
>>            <t>To maximize compatibility with user agents, servers that wish to
>>            store arbitrary data in a cookie-value SHOULD encode that data, for
>> -          example, using Base 16 <xref target="RFC4648" />.</t>
>> +          example, using Base64 <xref target="RFC4648" />.</t>
>>
>>            <t>The portions of the set-cookie-string produced by the cookie-av
>>            term are known as attributes.  To maximize compatibility with user
>
> WFM, and that seems to capture list discussion.
>
> Adam, I'll follow up with the remaining IESG members this week and
> perhaps ask you to submit a revised I-D so we can finish this off. :)

Yay!

Adam