Re: [v6ops] Same interface ID under several prefixes

Hi, Brian,

MacOS and OpenBSD also implement RFC7217/RFC8064.

For embedded devices (e.g. printers), they are probably based on older 
versions of the Linux kernel, and probably RFC7217 has not (and will 
not) be back-ported to them -- so it'll take time for these devices to 
adopt RFC7217.

As for Android, there might be a similar issue going on -- but certainly 
Lorenzo or Erik will be in a better position to tell.

So my "concern" would probably be just the lack of support in Windows.

P.S.: When it comes to Linux, it's more than just the kernel -- e.g. 
there's an implementation in dhcpcd (that's what you probably see in 
Raspberry Pi), and an implementation in NetworkManager (and there might 
be one in systemd-networkd).

Thanks,
Fernando

On 21/6/22 19:56, Brian E Carpenter wrote:
> Hi,
> 
> I've done a little survey on my home network, and I don't find the results
> very encouraging for RFC7217/RFC8064 deployment. In summary, there is
> some usage of pseudorandom IDs, but only Linux deserves a gold star
> (the PI is also Linux):
> 
> Linux 5.4.0   - 3 different IIDs for GUA, ULA, LLA
> Raspberry PI  - 3 different IIDs for GUA, ULA, LLA
> Android 7     - same IID for GUA, ULA; different for LLA (EUI64)
> Android 11    - same IID for GUA, ULA; different for LLA (EUI64)
> Windows 10*   - same IID for GUA, ULA, LLA
> FritzBox 7530 - same IID for GUA, ULA, LLA (EUI64)
> Samsung TV s6 - same IID for GUA, LLA (EUI64, but also temporary IID for 
> GUA & ULA)
> Chromecast 2  - LLA only (EUI64)
> Canon TS5100  - LLA only (EUI64)
> 
> * with temporary addresses switched off
> 
> Regards
>     Brian Carpenter
> 
> On 18-Jun-22 10:20, Fernando Gont wrote:
>> On 17/6/22 17:51, Brian E Carpenter wrote:
>> [...]
>>>>
>>>> I assume they don't claim to implement RFC7217. -- If they did, then
>>>> yes, it would be fair to call that a bug. :-)
>>>
>>> Right, it would be fairer to call it a potential privacy vulnerability
>>> (discover one address, get another one free of charge).
>>
>> Indeed, their mechanism allows for host-tracking: i.e., once you know
>> the token, you can predict what's the address that that node would
>> configured if it connected to a given network.
>>
>>
>>> I don't regard
>>> it as a very serious problem that an outsider can learn my ULA or
>>> LLA.
>>
>> The biggest problem is that once the attacker learns your token, e.g.,
>> he can test whether you're connected to e.g. the IETF conference network
>> by e.g. pinging PREFIX::your_token.
>>
>>
>>
>>> Kudos to MS, anyway, for having moved to pseudo-random IIDs very early,
>>> before RFC7217 in fact.
>>
>> Yes, that was the point I was trying to make!
>>
>> Thanks,
> 
> _______________________________________________
> v6ops mailing list
> v6ops@ietf.org
> https://www.ietf.org/mailman/listinfo/v6ops

-- 
Fernando Gont
SI6 Networks
e-mail: fgont@si6networks.com
PGP Fingerprint: 6666 31C6 D484 63B2 8FB1 E3C4 AE25 0D55 1D4E 7492