Re: [radext] [Add] [OPSAWG] 🔔 WG LC: RADIUS Extensions for Encrypted DNS

[Bernie Volz <[e-mail]>]

I was thinking more to put this restriction on the dhcp server, when it makes use of the Radius attribute to respond to a client. I have no issue with it being limited at configuration too, but the dhcp server should also make sure only a limited set of options are sent to client.

Leaving this wide open causes issues as it may be miss used to inject things that really shouldn’t be.


Looking at it again, it is also unclear how a dhcp server is to use information. For example, does the server use options from this information before its own configuration or only if it has no configuration (I suspect the former, as this is more client/request specific).

And from RFC7037, there is

169        DNS-Server-IPv6-Address     [RFC6911]

Does this mean someone could now place the DNS server option into your new Radius attribute instead of using this attribute to have the server map it to the DHCP option?


It seems to me that the reason for doing this is to handle the OPTION_V6_DNR only, so maybe best to restrict just to this for now? Future documents could add more to registry for options allowed.

- Bernie (from iPad)

> On Oct 17, 2022, at 2:15 AM, [e-mail] wrote:
> 
> 
> Hi Bernie,
>  
> Thank you for the feedback.
>  
> I have considered a registry to declare the options that can be echoed in the RADIUS attribute, but I then give it up because that list will be restricted anyway by policy:  
>  
>    RADIUS implementations may support a configuration parameter to
>    control the DHCP options that can be included in a DHCP*-Options
>    RADIUS attribute.
>  
> Cheers,
> Med
>  
> De : Add <[e-mail]> De la part de Bernie Volz
> Envoyé : vendredi 14 octobre 2022 17:48
> À : BOUCADAIR Mohamed INNOV/NET <[e-mail]>
> Cc : [e-mail]; Joe Clarke (jclarke) <[e-mail]>; opsawg <[e-mail]>; ADD Mailing list <[e-mail]>; [e-mail]
> Objet : Re: [Add] [OPSAWG] 🔔 WG LC: RADIUS Extensions for Encrypted DNS
>  
> Hi:
>  
> Your github document is -03 and published is -03, so likely you want to make it -04?
>  
> As no dhcp options are being defined and they are just being encapsulated in Radius attributes, not exactly sure how much the DHC wg can (or needs to) comment?
>  
> This basically changes things so you no longer have unique Radius attributes that are mapped to DHCP options, but you just use the DHCP options directly. This seems fine. (It does complicate the Radius configuration to handle DHCP option configuration if you don’t want them to be hand encoded as octet data, and many of the encoding/validation rules are not as consistent as we would like, especially for older options.)
>  
> The one concern for DHC wg may be to restrict the options that a DHCP server can send out if these options are intended to be delivered to the client via the dhcp server … for example, one would not want address or prefix delegation options to be allowed. This might be something similar to https://datatracker.ietf.org/doc/rfc6422/ which created a new registry for the allowed DHCPv6 options that can be provided by a relay agent (in this case encoded in the attributes).
> 
> - Bernie Volz
> 
> 
> On Oct 14, 2022, at 10:45 AM, [e-mail] wrote:
> 
> Hi Bernie, dhcwg, 
> 
> We received a comment during the WGLC of this draft that might lead us to revisit the design you have reviewed recently. This alternative design mirrors what we have done in 7037 (dhcwg) but with DHCP options included in RADIUS. The candidate text is available at: 
> 
> https://github.com/boucadair/draft-ietf-opsawg-add-encrypted-dns/blob/main/draft-ietf-opsawg-add-encrypted-dns-encap.txt
> 
> I'd appreciate if you can review this proposal and share any comments/issues you may have.
> 
> Thank you.
> 
> Cheers,
> Med
> 
> 
> -----Message d'origine-----
> De : BOUCADAIR Mohamed INNOV/NET
> Envoyé : vendredi 14 octobre 2022 16:32
> À : 'Alan DeKok' <[e-mail]>
> Cc : Ben Schwartz <[e-mail]>; Joe Clarke (jclarke)
> <[e-mail]>; opsawg <[e-mail]>; [e-mail];
> ADD Mailing list <[e-mail]>
> Objet : RE: [Add] [OPSAWG] 🔔 WG LC: RADIUS Extensions for
> Encrypted DNS
>  
> Re-,
>  
> Works for me. Thanks.
>  
> I will run this candidate version with dhcwg as well.
>  
> Cheers,
> Med
>  
> -----Message d'origine-----
> De : Alan DeKok <[e-mail]> Envoyé : vendredi 14
> octobre 2022 16:00 À : BOUCADAIR Mohamed INNOV/NET
> <[e-mail]> Cc : Ben Schwartz
> <[e-mail]>;
> Joe Abley <[e-mail]>; Ben Schwartz
> <bemasc=[e-mail]>; Joe Clarke (jclarke)
> <[e-mail]>; opsawg <[e-mail]>; [e-mail];
> ADD
> Mailing list <[e-mail]> Objet : Re: [Add] [OPSAWG] 🔔 WG LC:
> RADIUS Extensions for Encrypted DNS
>  
>  
> On Oct 14, 2022, at 5:47 AM, <[e-mail]>
> <[e-mail]> wrote:
> Let's try to exercise this approach and see if there are not
> hidden complications vs. current design with known limitation. A
> drafty text (not yet in the main draft) can be seen at:
> https://github.com/boucadair/draft-ietf-opsawg-add-encrypted-
> dns/blob/main/draft-ietf-opsawg-add-encrypted-dns-encap.txt
>  
>  Nits:
>  
> Section 3: just drop the ASCII art.  RFC 8044 makes it no longer
> necessary.
>  
> Section 3.1, 3.2, and 7.1: the data type should be "string" for
> "opaque data"
>  
>  Other than that, it looks good on first read-through.
>  
> The attributes should not be seen as opaque data by the RADIUS
> server but it should understand the encoding of the enclosed
> options.
> The intended behavior should be called out, IMO.
>  
>  I would suggest saying something like "for ease of
> administrator
> configuration, the RADIUS server SHOULD expose the DHCP options
> and
> allow administrators to configure them, instead of requiring
> them to
> be entered as opaque data".
>  
>  That gets the best of both worlds.
>  
>  Alan DeKok.
> 
> 
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