Re: setup question : mschap + perl authentication

2007-07-10 Thread Stefan Winter
Hi,

> Ah yes, I can see that being a problem, damn this means we can't offer
> any JRS authenticated services other than wireless and wired network
> access. We were planning on a few kiosks dotted around campus... though in
> theory if those Kiosks supported EAP Based login, the tunnel would be
> between the Kiosk and the users Home RADIUS server... Would this be
> acceptable, Or would the fact that we could still theoretically capture the
> users credentials from the login screen be an issue ?

Well, Alan mentioned pGina, and that would sort of fulfill the security 
requirements. It's still somewhat borderline, because you are supposed to 
enter something on an untrusted computer (mind keyboard sniffers et al). 
eduroam was meant as a WLAN infrastructure for *your own* laptop. An exact 
border on where to stop calling things eduroam remains to be drawn.
Application-layer authentication is usually something to be taken care of by 
an application-level AAI infrastructure.

> > Note also that your problems _can_ be solved quite cleanly,
>
> Shibboleth is in no way clean ! It's an evil necessary... actually the
> Idea is good ,Just the WAYF page is just so horribly cludgy.
> I think the idea of a pre-login form on the authenticated service would
> be a good idea.
> You enter your username string [EMAIL PROTECTED], this sets a identification
> cookie containing that string and redirects you to your home gateway
> (using a central list of domain->gateway mappings) . You then provide
> your password at your home gateway, which then directs you back to the
> page where you were originally sent from.
> No nasty WAYF pages.

Not working heavily on AAI stuff other than eduroam, I can take it easy here 
and just say: *shrug* however you implement it, I don't particularly care.

> > RADIUS. Put your captive portal behind a AAI infrastructure such as
> > Shibboleth. Workflow is...
>
> Were implementing shibboleth already, due to go live summer 2008...
>
> > That way, the user only reveals his credentials to home, not the visited
> > inst. There is a nice paper and prototype impl of this for Shibboleth, I
> > can look up the source if you're interested.
>
> I've read more shibboleth technical documentation than I would care to
> already, but thanks for the offer .

That one actually made me laugh :-) I guess Shibboleth even beats the 
legendary 12-pound UNIX manuals.

> No, quite. So this would be a kind of walled garden approach using
> shibboleth for authentication ?

It's not a walled garden: eduroam's sister project eduGAIN (educational GEANT 
Authentication Infrastructure) provides tools to cross technology borders, 
i.e. if you have a non-Shibboleth Identity Provider for your credentials and 
a Shibboleth service, eduGAIN will translate the requests from one language 
to another and make them interoperate. So, in short, ANY AAI infrastructure 
will do (as long as an eduGAIN adapter ["bridging element"] exists). So, it's 
not like you are tied to Shibboleth. We have a cross-federation service 
already between PAPI and Shibboleth, A-Select soon to come...

But I guess we're drifting off-topic here... sorry.

Stefan

-- 
Stefan WINTER

Stiftung RESTENA - Réseau Téléinformatique de l'Education Nationale et de 
la Recherche
Ingenieur Forschung & Entwicklung

6, rue Richard Coudenhove-Kalergi
L-1359 Luxembourg
E-Mail: [EMAIL PROTECTED]     Tel.:     +352 424409-1
http://www.restena.lu                Fax:      +352 422473


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Re: setup question : mschap + perl authentication

2007-07-10 Thread A . L . M . Buxey
Hi,

> Ah yes, I can see that being a problem, damn this means we can't offer 
> any JRS authenticated services other than wireless and wired network access.
> We were planning on a few kiosks dotted around campus... though in 
> theory if those Kiosks supported EAP Based login, the tunnel would be 
> between the Kiosk and the users Home RADIUS server... Would this be 
> acceptable, Or would the fact that we could still theoretically capture 
> the users credentials from the login screen be an issue ?
> > Note also that your problems _can_ be solved quite cleanly,
> Shibboleth is in no way clean ! It's an evil necessary... actually the 
> Idea is good ,Just the WAYF page is just so horribly cludgy.
> I think the idea of a pre-login form on the authenticated service would 
> be a good idea.


install pGina on the kiosk systems, for example...and let those kiosk systems
talk directly back to your ORPS RADIUS server. the request will then
be proxied through to the home site if they are a visitor (ie dont enter
your realm)

alan
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Re: setup question : mschap + perl authentication

2007-07-10 Thread Arran Cudbard-Bell

>  credentials in it. Authenticates 
> user and relays the outcome as PAP reply. This solves the en-route problem, 
> but cannot overcome the problem that still the visited inst *has* your 
> password.
>   
Ah yes, I can see that being a problem, damn this means we can't offer 
any JRS authenticated services other than wireless and wired network access.
We were planning on a few kiosks dotted around campus... though in 
theory if those Kiosks supported EAP Based login, the tunnel would be 
between the Kiosk and the users Home RADIUS server... Would this be 
acceptable, Or would the fact that we could still theoretically capture 
the users credentials from the login screen be an issue ?
> Note also that your problems _can_ be solved quite cleanly,
Shibboleth is in no way clean ! It's an evil necessary... actually the 
Idea is good ,Just the WAYF page is just so horribly cludgy.
I think the idea of a pre-login form on the authenticated service would 
be a good idea.
You enter your username string [EMAIL PROTECTED], this sets a identification 
cookie containing that string and redirects you to your home gateway 
(using a central list of domain->gateway mappings) . You then provide 
your password at your home gateway, which then directs you back to the 
page where you were originally sent from.
No nasty WAYF pages.

Unfortunately this would mean you could be identified, and I know thats 
a big feature of Shibboleth... that Service providers don't know who's 
using their service, just that they've been authorised to do so.

*sigh* there must be a solution , just no ones figured it out yet .
>  but without 
> RADIUS. Put your captive portal behind a AAI infrastructure such as 
> Shibboleth. Workflow is...
>   
Were implementing shibboleth already, due to go live summer 2008...
> That way, the user only reveals his credentials to home, not the visited 
> inst. 
> There is a nice paper and prototype impl of this for Shibboleth, I can look 
> up the source if you're interested.
>   
I've read more shibboleth technical documentation than I would care to 
already, but thanks for the offer .
> Why don't we do that then? The wireless link is still unencrypted with this 
> ansatz. Again a violation of our security mimimums. And this problem is a lot 
> harder to solve than authentication above. We would probably need to go to 
> the IEEE asking for a "WPA2-Noauth-JustEncrypt" profile, where the AP just 
> hands out a EAPoL-Key to the client, performing no prior authentication. This 
> would just encrypt the link, and authentication could take palce with the 
> above thing. *Then*, web-redirect is again a viable alternative. But going to 
> the IEEE is not exactly a walk in the park.
>
>   
No, quite. So this would be a kind of walled garden approach using 
shibboleth for authentication ?
> Greetings,
>
> Stefan
>
>   
Regards,
Arran

-- 
Arran Cudbard-Bell ([EMAIL PROTECTED])
Authentication, Authorisation and Accounting Officer
Infrastructure Services | ENG1 E1-1-08 
University Of Sussex, Brighton
EXT:01273 873900 | INT: 3900

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Re: setup question : mschap + perl authentication

2007-07-10 Thread Stefan Winter
Hi,

> What exactly was the issue with doing PAP over Eduroam ? Was it people
> being afraid of passing weakly encrypted passphrases around the
> interweb, or home sites just not bothering to implement PAP on their
> Radius servers ?

No, the issue is a different one: you will have to enter your credentials on 
the visited site, and it will either 

a) be able to see them (using outright PAP)
b) send you a beautiful/ugly PHP/JS piece of code to encrypt stuff - but then
   the user would need to trust that piece of code from an inst he doesn't
   know

Both of these give the visited inst a chance to get hold of your credentials. 
With EAP and TLS tunnels, this is conceptually not possible and is thus 
stronger. eduroam security standards don't allow that your password is 
visible anywhere but at home (if at all).

Note that the interweb thingy is not that critical, it can be overcome: 
visited inst RADIUS server gets PAP credentials, initiates its own 
EAP-TTLS-PAP session to home, puts user's credentials in it. Authenticates 
user and relays the outcome as PAP reply. This solves the en-route problem, 
but cannot overcome the problem that still the visited inst *has* your 
password.

Note also that your problems _can_ be solved quite cleanly, but without 
RADIUS. Put your captive portal behind a AAI infrastructure such as 
Shibboleth. Workflow is:
- user gets captive portal page
- is asked "Where are you from" -> enters realm or selects text box
- Firewall for his IP address is opened _only_ for his home AAI place
- gets redirected to his own AAI place (can verify TLS cert, connection
  is encrypted)
- authenticates at home, gets cookie / session ID so that captive portal gets
  informed that he's properly authenticated
- firewall opens for all traffic

That way, the user only reveals his credentials to home, not the visited inst. 
There is a nice paper and prototype impl of this for Shibboleth, I can look 
up the source if you're interested.
Why don't we do that then? The wireless link is still unencrypted with this 
ansatz. Again a violation of our security mimimums. And this problem is a lot 
harder to solve than authentication above. We would probably need to go to 
the IEEE asking for a "WPA2-Noauth-JustEncrypt" profile, where the AP just 
hands out a EAPoL-Key to the client, performing no prior authentication. This 
would just encrypt the link, and authentication could take palce with the 
above thing. *Then*, web-redirect is again a viable alternative. But going to 
the IEEE is not exactly a walk in the park.

Greetings,

Stefan

-- 
Stefan WINTER

Stiftung RESTENA - Réseau Téléinformatique de l'Education Nationale et de 
la Recherche
Ingenieur Forschung & Entwicklung

6, rue Richard Coudenhove-Kalergi
L-1359 Luxembourg
E-Mail: [EMAIL PROTECTED]     Tel.:     +352 424409-1
http://www.restena.lu                Fax:      +352 422473


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Re: setup question : mschap + perl authentication

2007-07-10 Thread Arran Cudbard-Bell
Phil Mayers wrote:
> On Mon, 2007-07-09 at 22:44 +0100, Arran Cudbard-Bell wrote:
>   
>> Alan DeKok wrote:
>> 
>>> Johan wrote:
>>>   
>>>   
 I'm wondering if it's possible to authenticate a user who is using
 mschap authentication with perl.
 
 
>>>   Sure.  Just re-write all of the MS-CHAP authentication protocol in
>>> rlm_mschap in Perl.
>>>
>>>   But why the heck would you want to do that?
>>>
>>>   
>>>   
>> You know i've been thinking of doing that in PHP (PHP Based supplicant 
>> for weblogin via RADIUS), i'm sure it's possible... and it would be of 
>> some benefit, just the RFC makes my head hurt... one of the few times 
>> I've  regreted not studying computer science. *sigh* something to do 
>> with hashing the nt hash using different sha functions.
>> 
>
> I suggested this to a BlueSocket rep after my 802.1x talk at NetworkShop
> 2006 (I think...) to get over the problems of PAP on eduroam - but my
> suggestion went further and was to do it in JavaScript on the browser,
> have the server simply act as a relay.
>
> I imagine that'd be even trickier. I got about an hour into coding it
> and lost the will to live...
>   
Trying to code an MSCHAP client in JS thats just insane ?! But kudos for 
trying.
It appears that there is actually a wrapper class in the pecl repository 
to do PAP , ChapMD5, MSChapV1 MSChapV2. You'd need the Radius extension 
installed, though that too can be downloaded from pecl.

What exactly was the issue with doing PAP over Eduroam ? Was it people 
being afraid of passing weakly encrypted passphrases around the 
interweb, or home sites just not bothering to implement PAP on their 
Radius servers ?
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Re: setup question : mschap + perl authentication

2007-07-10 Thread Phil Mayers
On Mon, 2007-07-09 at 22:44 +0100, Arran Cudbard-Bell wrote:
> Alan DeKok wrote:
> > Johan wrote:
> >   
> >> I'm wondering if it's possible to authenticate a user who is using
> >> mschap authentication with perl.
> >> 
> >
> >   Sure.  Just re-write all of the MS-CHAP authentication protocol in
> > rlm_mschap in Perl.
> >
> >   But why the heck would you want to do that?
> >
> >   
> You know i've been thinking of doing that in PHP (PHP Based supplicant 
> for weblogin via RADIUS), i'm sure it's possible... and it would be of 
> some benefit, just the RFC makes my head hurt... one of the few times 
> I've  regreted not studying computer science. *sigh* something to do 
> with hashing the nt hash using different sha functions.

I suggested this to a BlueSocket rep after my 802.1x talk at NetworkShop
2006 (I think...) to get over the problems of PAP on eduroam - but my
suggestion went further and was to do it in JavaScript on the browser,
have the server simply act as a relay.

I imagine that'd be even trickier. I got about an hour into coding it
and lost the will to live...

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Re: setup question : mschap + perl authentication

2007-07-09 Thread Alan DeKok
Arran Cudbard-Bell wrote:
> And the advantage of supporting MSChap is that you don't have to store 
> your passwords in cleartext... Just NT4 or LMHash which while not much 
> more secure than cleartext , looks far more impressive in a password 
> database.

  And the server already does the heavy lifting of implementing MS-CHAP.
 Why re-invent the wheel?

> You ok Alan ? You've seemed less yeah go look at this howto / man page 
> and more *stab stab* die recently ...

  Questions like "why are you so mean" can't be answered with "read this
man page".  They require careful analysis.  Though the incidence of such
complaints did go down after Section 5 was added to the top-level README.

  Alan DeKok.
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Re: setup question : mschap + perl authentication

2007-07-09 Thread Arran Cudbard-Bell
Alan DeKok wrote:
> Johan wrote:
>   
>> I'm wondering if it's possible to authenticate a user who is using
>> mschap authentication with perl.
>> 
>
>   Sure.  Just re-write all of the MS-CHAP authentication protocol in
> rlm_mschap in Perl.
>
>   But why the heck would you want to do that?
>
>   
You know i've been thinking of doing that in PHP (PHP Based supplicant 
for weblogin via RADIUS), i'm sure it's possible... and it would be of 
some benefit, just the RFC makes my head hurt... one of the few times 
I've  regreted not studying computer science. *sigh* something to do 
with hashing the nt hash using different sha functions.

Got PAP working though thats not exactly hard... and CHAP seems very 
easy , so i'll do that tomorrow.

Have a request hash 
Hash this hash with a hash of the password 
Here have the request hash and the hash of the request hash with the 
password.. 
*works*

And the advantage of supporting MSChap is that you don't have to store 
your passwords in cleartext... Just NT4 or LMHash which while not much 
more secure than cleartext , looks far more impressive in a password 
database.

But yes, as Alan said, why bother implimenting the server side MSChap 
module in perl ... rlm_perl wasn't really designed for this kind of 
stuff, more for request flow control and acquiring extra attributes from 
databases and various other perly type things.

You ok Alan ? You've seemed less yeah go look at this howto / man page 
and more *stab stab* die recently ...

Sorry abundance of Guinness ...

Thanks,
Arran
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Re: setup question : mschap + perl authentication

2007-07-09 Thread Alan DeKok
Johan wrote:
> I'm wondering if it's possible to authenticate a user who is using
> mschap authentication with perl.

  Sure.  Just re-write all of the MS-CHAP authentication protocol in
rlm_mschap in Perl.

  But why the heck would you want to do that?

> I already made a perl script, which I use with rlm_perl to authenticate
> users to an ftp backend. I use that script to authenticate users from
> the authentication proxy of a Cisco PIX.

  Does the FTP backend support MS-CHAP?  If not, there's no point in
writing any Perl code to integrate the two.

> My next setup is to authenticate user requests from a Wireless Access
> Point with EAP-TTLS.
> Is it possible to do that with the radiusd.conf ?
> 
> I already tried to setup like this in the authenticate section :
> 
> mschap {
>   perl
> }
> 
> But problem is, the perl script doens't seems to receive the same
> information as a PIX request. Do I need to modify my script to talk
> mschap ?

  I think you're randomly trying to get something to work, without
understanding what's going on.

> Is there a perl module to understand the mschap protocol ?

  Look on CPAN.  We don't manage Perl packages here.

  Alan DeKok.
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setup question : mschap + perl authentication

2007-07-09 Thread Johan

Hi community

I have a question for you guys.

I'm wondering if it's possible to authenticate a user who is using mschap
authentication with perl.

I already made a perl script, which I use with rlm_perl to authenticate
users to an ftp backend. I use that script to authenticate users from the
authentication proxy of a Cisco PIX.

My next setup is to authenticate user requests from a Wireless Access Point
with EAP-TTLS.
Is it possible to do that with the radiusd.conf ?

I already tried to setup like this in the authenticate section :

mschap {
 perl
}

But problem is, the perl script doens't seems to receive the same
information as a PIX request. Do I need to modify my script to talk mschap ?


Is there a perl module to understand the mschap protocol ?

Thanks in advance,

Johan
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