Subject: Re: [Ltru] AD issue #14 (DoS potential) Additional issues with 4646bis raised by an Apps Review Team review

From: "Doug Ewell" <[email-masked]>
Date: Mon, 8 Jun 2009 20:10:36 -0600

Alexey Melnikov <alexey dot melnikov at isode dot com> wrote:

> BTW, are people aware of implementations that try to download Language 
> Tag registry automatically?

I've written one as an experiment.  I don't think anyone will ever 
write, say, a Web browser that hits the Registry every time a page is 
loaded, or even on program startup.  The performance penalty on the app 
would be substantial.  Only a dedicated language tag validation tool 
would even conceivably have the need to do such a thing, and there will 
never be many of those.

> Regarding I): application should be advised against frequent polling 
> of the registry. For example:

I thought we said that already.

> It might also be worth discussing how the registry format facilitates 
> "diffing" 2 versions of the registry.

I don't understand why anyone would want to do that, except of course 
for someone reviewing our work right now.

--
Doug Ewell  *  Thornton, Colorado, USA  *  RFC 4645  *  UTN #14
http://www.ewellic.org
http://www1.ietf.org/html.charters/ltru-charter.html
http://www.alvestrand.no/mailman/listinfo/ietf-languages  ˆ

---

From: "Doug Ewell" <[email-masked]>
Date: Mon, 8 Jun 2009 20:19:55 -0600

"Phillips, Addison" <addison at amazon dot com> replied to Alexey:

>>> "There is a subtlety in the ABNF production 'variant': a variant 
>>> starting with a digit has a minimum length of four characters,
>>
>> While this is true, I think deleting the word "minimum" here would 
>> fix the problem.
>
> No. It would be wrong.
>
> A requested variant subtag starting with a digit may be up to eight 
> characters (letters or digits) long. They can be as short as four 
> characters. A request for a subtag starting with a letter must be at 
> least five in length. Removing the word "minimum" would make it mean 
> that a variant starting with a digit could only be four characters 
> long.

We already have three registered variants (1606nict, 1694acad, 1959acad) 
which demonstrate that 4 characters is only the minimum.