[UA-discuss] UASG010 - Quick Guide to Linkification

Asmus Freytag (c) asmusf at ix.netcom.com
Sat Sep 30 02:40:40 UTC 2017

On 9/29/2017 5:28 PM, Tex Texin wrote:
> Thanks Mark and Asmus.
> I agree about the distinction of script mixing within a label. The 
> guide should clarify this.
> Also support Asmus clarification regarding ASCII vs all of Latin.
> For the attention to mixing digits within a label, I agree although I 
> would need to review if I can easily know which digits are widely used 
> vs of historical interest. I don’t believe that being a bit broad in 
> linkification acceptance is a problem. The domain registry (and 
> perhaps servers) should be more restrictive to not allow domains that 
> could represent spoofing. (I know there are problems with reliance on 
> registries). Being too restrictive in linkification could hurt users 
> that need to enter a legitimate URL and can’t.

Digits come in sets that are specified as such in the Unicode Standard 
(although implicitly: the members of such sets have a property "decimal 
digit" and Unicode follows the convention of encoding these in complete 
sets from 0-9). Therefore, not linkifying something that contains a 
mixture of these sets can be implemented deterministically (although 
regex syntax leads to particularly grim expressions for specifying this 
constraint, it can be done).

Realistically, only the modern set of about 30 scripts is of practical 
importance, so a scheme that does not track the addition of future 
historic alphabets in Unicode would be adequate....

Where native digits are (largely) historic holdovers, we wouldn't need 
them at all, but linkification isn't a good place to filter those.

Some reluctance on automatic conversions of "risky" URLs would be a 
benefit; it's along the same line as not linkifying something not under 
the author's control: the risk for mischief is just too great.

Forum software that I have been a user of tended to implement three 
restrictions that are not related to new TLDs or IDN TLDs:

1) limit file names by extension (e.g. if the link entered was supposed 
to be for an image, do not allow it to link to something that doesn't 
have a common image file extension).

2) disallow any link with a "?" in it - rationale: it's not a static 
link and who knows what will be served later (including risky stuff)

3) require http://, etc., even in text spans that are marked as being 
URLs or in link attributes.

In some cases these restrictions were deliberate decisions by forum 
operators - part of reigning in certain kinds of forum spam.

I feel we need to be cognizant of the needs for limiting the risk 
profile of certain operations - in particular where the result then 
winds up online to an open audience (as opposed to just sharing 
something in a private message).

The alternative for an operator is to simply blacklist specific TLDs and 
domains (and most of those will be any IDNs that are not local to the 

> And it seems we need to clarify our implied intent for the guidance 
> about the “implied intent of user’s entry”. J(I couldn’t resist any 
> longer.)
> Tex
> *From:*ua-discuss-bounces at icann.org 
> [mailto:ua-discuss-bounces at icann.org] *On Behalf Of *Mark Svancarek 
> via UA-discuss
> *Sent:* Friday, September 29, 2017 5:04 PM
> *To:* Asmus Freytag; ua-discuss at icann.org
> *Subject:* Re: [UA-discuss] UASG010 - Quick Guide to Linkification
> Hmm, I don’t recall approving that principle (hopefully it was added 
> while I was out on leave, and not just because I carelessly failed to 
> notice it was being added).
> I mention that because it seems the opposite of what we could 
> recommend i.e. we SHOULD allow use of Highly Restrictive and continue 
> to discourage Moderately Restrictive.  Do we need to revisit this?  
> Sorry if I am just confused.
> Note that, as Asmus points out, our concern is about script-mixing 
> within a label, not use of different scripts in different labels.  
> Tex’s examples are all the latter, and should linkify cleanly by 
> UA-ready SW.
> /marksv
> *From:*ua-discuss-bounces at icann.org 
> <mailto:ua-discuss-bounces at icann.org> 
> [mailto:ua-discuss-bounces at icann.org] *On Behalf Of *Asmus Freytag
> *Sent:* Friday, September 29, 2017 2:40 PM
> *To:* ua-discuss at icann.org <mailto:ua-discuss at icann.org>
> *Subject:* Re: [UA-discuss] UASG010 - Quick Guide to Linkification
> On 9/29/2017 2:26 PM, Tex Texin wrote:
>     Hi,
>     Some questions:
>      1. Do I understand correctly, that the recommendation to not
>         linkify highly restrictive strings means that
>         tex@普遍接受-测试.世界
>         <mailto:tex@%E6%99%AE%E9%81%8D%E6%8E%A5%E5%8F%97-%E6%B5%8B%E8%AF%95.%E4%B8%96%E7%95%8C>
>         would not become a link? Or http:// 普遍接受-测试.世界.com?
>     Highly restrictive means that latin cannot be mixed with Chinese
>     or Japanese characters.
> Some script mixing *within* a label should be restricted as it is a 
> security risk. Script mixing across a FQDN or between local part and 
> host seem to be rather likely scenarios instead.
> For certain scripts, ASCII admixture (just ASCII, not all of Latin) 
> would be common practice in the writing system and it may be common 
> enough/benign enough to allow it.
> However, you might also want to address European digits for those 
> scripts where native digits exist and are widely / predominantly used, 
> vs. scripts where the native digits are more of historic/cultural 
> interest. (In Arabic you have both, depending on the region).
> Mixing digit sets in the same label should be a no-no and indicated 
> something's not well-formed.
>      2. I do not understand “Linkification should be determined by the
>         implied intent of the user's entry” Is this intended to mean
>         that the scheme (http, mailto, etc) should be added to form
>         the link? Or some other determination of intent? If the
>         former, it should be stated more clearly.
> My naive interpretation had to do with things like tables or data 
> records where the purpose of a particular field would be a URL.
>     tex
>     *From:*ua-discuss-bounces at icann.org
>     <mailto:ua-discuss-bounces at icann.org>
>     [mailto:ua-discuss-bounces at icann.org] *On Behalf Of *Don Hollander
>     *Sent:* Thursday, September 28, 2017 11:19 AM
>     *To:* Universal Acceptance
>     *Subject:* [UA-discuss] UASG010 - Quick Guide to Linkification
>     A quick update on Linkification
>     We have published an updated Quick Guide to Linkification
>     https://uasg.tech/wp-content/uploads/2017/06/UASG010-Quick-Guide-to-Linkification.pdf
>     <https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fuasg.tech%2Fwp-content%2Fuploads%2F2017%2F06%2FUASG010-Quick-Guide-to-Linkification.pdf&data=02%7C01%7Cmarksv%40microsoft.com%7Ce0ff7a322ef44f31a64208d507829df2%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C1%7C636423179950153243&sdata=gGQ5xhFTuJLf1kkFXWsOnfGdOH%2FMb0XbhK7tLiJfqzQ%3D&reserved=0>
>     This builds on discussions we had post the UASG meeting in Seattle
>     in April.
>     We are also working on an evaluation of Linkification in major
>     Social Media Communication applications.   (Here’s the link to the
>     Help Wanted advertisement - Help Wanted: Linkification Evaluation
>     <https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fuasg.tech%2Fwp-content%2Fuploads%2F2016%2F11%2FHelp-Wanted%25E2%2580%25A6-Linkification-Evaluation-1.0.pdf&data=02%7C01%7Cmarksv%40microsoft.com%7Ce0ff7a322ef44f31a64208d507829df2%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C1%7C636423179950153243&sdata=EuBYBxDZgX1FbvYLIbUE6RKuC4Jhk%2B7DQSrRa5guzH4%3D&reserved=0>)
>     This evaluation is being built on a replicable testing platform so
>     that we can readily repeat the process in the future.   While
>     early days, we expect to provide a preliminary report during the
>     ICANN60 meeting.   As we go through the testing it is raising some
>     additional questions about our Good Practice guide and
>     expectations.  We fully expect that once the evaluation is
>     completed we’ll again review UASG010 based on real world experiences.
>     Don
>     Don Hollander
>     Universal Acceptance Steering Group
>     Skype: don_hollander

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