Andy, Carsten, Jürgen, Tom,

Thanks for your feedbacks

If I understand correctly:

  *   Andy, Carsten and Jürgen agree that using unrestricted string for non-key 
attributes makes sense
  *   Andy has a concern only about using unrestricted string for key 
attributes and his proposal is to use the yang-identifier (which does not bound 
the maximum length of the string) instead

Is my understanding correct?

I think that what I have understood would make sense

Any other opinion or suggestion?

Thanks, Italo

From: Andy Bierman <[email protected]>
Sent: giovedì 12 gennaio 2023 19:24
To: Jürgen Schönwälder <[email protected]>; Andy Bierman 
<[email protected]>; Italo Busi <[email protected]>; [email protected]
Subject: Re: [netmod] Use of unrestricted string in YANG (was RE: naming scope 
of a grouping which uses a grouping)



On Thu, Jan 12, 2023 at 8:33 AM Jürgen Schönwälder 
<[email protected]<mailto:[email protected]>>
 wrote:
On Thu, Jan 12, 2023 at 07:08:05AM -0800, Andy Bierman wrote:
>
> Just because the escaped string is "safe" inside a NETCONF protocol message
> does not mean it is safe to use in other tools. Data (especially list keys)
> gets moved
> between software programs. Unrestricted strings increase the risk of data
> injection attacks.
>

Sorry, broken code that does not handle inputs of unexpected length
can't be secured by standardizing arbitrary limits. The only option is
to fix the broken code. Code that fails to validate its inputs can't
be fixed by arbitrary limits and the pure hope that the broken code
will never see something causing it to crash.


My statement is about the risk of using unconstrained values in strings, not 
the length.
It is my preference to avoid characters in leaf keys that are known to cause 
problems
with shells and other tools.

It is a tradeoff. You can have the freedom to construct all-whitespace key 
leafs,
but at the risk of implementations not handling it correctly.  The designer(s) 
should pick the most
appropriate type, based on priorities.

/js

Andy

--
Jürgen Schönwälder              Constructor University Bremen gGmbH
Phone: +49 421 200 3587         Campus Ring 1 | 28759 Bremen | Germany
Fax:   +49 421 200 3103         <https://www.jacobs-university.de/>
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