Crista,
*> The bottom line question in my email, phrased in OpenID terminology, is
whether we*
*> can use **the Viewer's IP address as the token.
*
My question is, would you really want to use the Viewer's IP address as the
token? What IP address would it specifically use?
If a user were on an internal LAN, would it use the 192.168.1.x IP address
(local internal LAN address) or 10.x.x.x? or 172.x.x.x?
Or would it use the external routable IP address (from the ISP)? If that
were the case, then wouldn't 2 viewers that are accessing a server from the
same location (for example a library, or school, or work/office) where
multiple computers on the same internal LAN would try to connect to an
external grid server, then wouldn't the viewer's all have the same IP
address?
Keep in mind, that most users are using NAT behind their firewall, so what
IP address would you even use for the token?
A better address would be the hostname address (hostn...@domain.com). This
way each and every machine would always hava a unique hostname, and it's
tied to a specifc domain (whether it's an internal domain, a LAN, or even
the WAN/ISP domain name given by your local ISP, such as a local comcast
user:
hostn...@be-70-ar01.area1.il.chicago.comcast.net
It might make more sense to use hostname instead of an IP address. So maybe
use the machine's full FQDN hostname as the token?
I still think a RADIUS server would be the best bet (the solution I
described in the message below), as the best possible longterm solution to
this problem.
We would probably need to create some type of "RADIUS" module for OpenSim.
Mark
On Mon, Feb 23, 2009 at 3:29 PM, Mark Malewski <mark.malew...@gmail.com>wrote:
>
>
> On Mon, Feb 23, 2009 at 3:28 PM, Mark Malewski <mark.malew...@gmail.com>wrote:
>
>> Crista,
>>
>> Sounds like you are on the right track. Sounds like a very "logical"
>> process, but why not use something like 802.1x/EAP?
>> *> So, what can we do to detect the legitimacy of agents?*
>>
>> Instead of a "Finnish Magic", why not use 802.1x and use a RADIUS server
>> for standard authentication?
>>
>> Using simple 802.1x, the authenticator sends an "EAP-Request/Identity"
>> packet to the supplicant as soon as it detects that the link is active (the
>> user has associated with the grid/radius server).
>>
>>
>> 1. The supplicant sends an "EAP-Response/Identity" packet to the
>> authenticator, which is then passed on to the authentication (RADIUS)
>> server.
>> 2. The authentication server sends back a challenge to the
>> authenticator, such as with a token password system. The authenticator
>> unpacks this from IP and repackages it into EAPOL and sends it to the
>> supplicant. Different authentication methods will vary this message and
>> the
>> total number of messages. EAP supports client-only authentication and
>> strong
>> mutual authentication. Only strong mutual authentication is considered
>> appropriate for the virtual world case.
>> 3. The supplicant responds to the challenge via the authenticator and
>> passes the response onto the authentication server.
>> 4. If the supplicant provides proper identity, the authentication
>> server responds with a success message, which is then passed onto the
>> supplicant. The authenticator now allows access to the LAN- - possibly
>> restricted based on attributes that came back from the authentication
>> server. For example, the authenticator might switch the supplicant to a
>> particular virtual LAN or install a set of firewall rules.
>>
>> 802.1x is a standard, and many wireless LAN vendors have latched onto
>> 802.1x standard to help authenticate and secure both wired and wireless
>> LANs. The greatest feature of 802.1x is interoperability.
>>
>> It would seem to make sense to just use 802.1x authentication, EAP is
>> supposed to head off proprietary authentication systems and let everything
>> from passwords to challenge-response tokens and public-key infrastructure
>> certificates all work smoothly.
>>
>> Why not just use a standard RADIUS server as the authentication server?
>> With 802.1x, the user or client that wants to be authenticated would be
>> called a "supplicant". The actual server doing the authentication
>> (typically a RADIUS server) is called the authentication server. The device
>> in between (such as a wireless access point, or any region/grid server) is
>> called the "authenticator". One of the key points is that the authenticator
>> can be simple and dumb, all of the "brains" have to be in the supplicant
>> and the authentication server.
>>
>> Each Grid could run their own separate RADIUS server, and user groups
>> could be setup to allow users to "hypergrid" between grids (securely). [By
>> setting up REALMS between Grids]
>>
>> Each grid would be responsible for checking the "legitimacy" of it's users
>> (via E-mail confirmation, etc.) and if any user was "up to no good" then
>> their user ID can be disabled, and their IP address can be blocked (by the
>> RADIUS server).
>>
>> http://freeradius.org/
>>
>> Using a standard FreeRADIUS server would make it extremely easy for Grid
>> Administrators to Administer User accounts. RADIUS would provide
>> centralized access, authentication and accounting management for users of
>> the Grid.
>>
>> http://en.wikipedia.org/wiki/RADIUS
>>
>> If someone attempted to "hijack" a secure session, the RADIUS server
>> checks that the information is correct using authentication schemes like
>> PAP, CHAP or EAP. The RADIUS server than returns one of three responses
>> ("Yea", "Nay", or "Challenge").
>>
>> The "Access Challenge" requests additional information from the user (such
>> as a secondary password, or a PIN number, mother's maiden name, secret
>> password, or a token or even a secureID card, biometrics, etc.)
>>
>> Similar to how a web-based online banking system (like Bank of America)
>> works. If you are using the same computer all the time, it only asks for
>> your username and password. If you attempt to login from a new or different
>> computer, then it kicks back an Access Challenge, and asks you for
>> additional information (like a secret password, or a PIN, or to verify your
>> mother's maiden name, or any of several challenge passwords that only the
>> actual user would know).
>>
>> If the Challenge is successful, then the secure tunnel is established
>> between the user machine and the RADIUS server (and access credentials are
>> completely hidden).
>>
>> By using RADIUS, we could also grant users access by groups. There could
>> be an "Administrators" groups setup, and "Moderator" groups, and "Peace
>> Keepers" groups, and various groups with certain permissions setup.
>>
>> Also certain information is stored in the RADIUS server (IP address of the
>> user, maximum length that the user may remain connected, an access list,
>> priority queue or other restrictions on a user's access, VLAN parameters,
>> QoS parameters, etc.)
>>
>> RADIUS is commonly used to facilitate roaming between ISPs, for example by
>> companies which provide a single global set of credentials that are usable
>> on many public networks. RADIUS facilitates this by the use of *realms*,
>> which identify where the RADIUS server should forward the AAA requests for
>> processing.
>>
>>
>> A realm is commonly appended to a user's user name and delimited with an
>> '@' sign, resembling an email address domain name. This is known a *
>> postfix* notation for the realm. Another common usage is *prefix*notation,
>> which involves prepending the realm to the username and using '\'
>> as a delimiter. Modern RADIUS servers allow any character to be used as a
>> realm delimiter, although in practice '@' and '\' are usually used.
>>
>> Realms can also be compounded using both prefix and postfix notation, to
>> allow for complicated roaming scenarios; for example, somedomain.com\
>> usern...@anotherdomain.com could be a valid username with two realms.
>>
>> Although realms often resemble email domains, it is important to note that
>> realms are in fact arbitrary text and need not contain real domain names.
>>
>> So users from different Grids could roam freely between "partnering" Grid
>> servers using realms.
>>
>> Proxy operations
>>
>> When a RADIUS server receives an AAA request for a user name containing a
>> realm, the server will reference a table of configured realms. If the realm
>> is known, the server will then *proxy* the request to the configured home
>> server for that domain. The behaviour of the proxying server regarding the
>> removal of the realm from the request ("stripping") is
>> configuration-dependent on most servers. In addition, the proxying server
>> can be configured to add, remove or rewrite AAA requests when they are
>> proxied.
>> I believe the first step would be to get a RADIUS server setup and
>> working, and then work on setting up two grids together (using REALM between
>> the two RADIUS servers) and then once this could be done, then later
>> additional grids could be "trusted" and allowed onto the network. So users
>> could roam freely between the "trusted grids".
>>
>> If a user was reported to the Grid Owner (as being an "abusive user") then
>> the Grid owner would suspend that user's account, and send an "abuse
>> notification" to the Grid Owner (that the user has violated the Terms of
>> Service for the Grid). Basically just "pull the plug" on that user's
>> account, and kick them off the grid, and ban their computer & IP address.
>>
>> It would make it extremely easy for "policing" the Grid, and any users
>> that want "Secure Inter-Grid" handshakes would just join the REALM network.
>>
>> Mark
>>
>> P.S. If you need some help with this, I'm sure we can sit down and discuss
>> it a bit, and set something up as a "demo" grid as to how this could be
>> done. Then later other Grids (like OS Grid, and various others) could join
>> the REALM grid network.
>>
>>
>>
>>
>> On Mon, Feb 23, 2009 at 2:19 PM, Toni Alatalo <ant...@kyperjokki.fi>wrote:
>>
>>> this kinda sounds like trying to achieve what rexauth does, no?
>>>
>>> perhaps someone could write how it is w.r.t to that case? i might be
>>> able, but too tired now and probably busy tomorrow.
>>>
>>> also John Hurliman is planning new auth stuff with openid and some
>>> openid related token thing (i forgot the name) which is basically 'same
>>> as rexauth but standards instead of Finnish magic', like he said the
>>> other day :) .. so perhaps he replies his plan there, seems to be online
>>> at least.
>>>
>>> ~Toni
>>>
>>> --~--~---------~--~----~------------~-------~--~----~
>>> this list: http://groups.google.com/group/realxtend
>>> realXtend home page: http://www.realxtend.org/
>>> -~----------~----~----~----~------~----~------~--~---
>>>
>>>
>>> Hi,
>>>
>>> I'm about to start tightening the ropes for the Hypergrid in order to
>>> make it safer, and also make safer some loose ends of OpenSim without
>>> HG, and I would appreciate feedback on this.
>>>
>>> The first issue that needs to be addressed is the issue of user
>>> authentication. The regions need to be able to verify that the agent
>>> that claims to be representing charles.kri...@osgrid.org is, indeed,
>>> representing charles.kri...@osgrid.org. (As you know, right now this
>>> is... err... a bit overlooked... *coughs*... and not just in the HG...
>>> *more coughs*).
>>>
>>> Having looked at OpenID, I came to the conclusion that it's not enough
>>> to know that osgrid.org has a user named "Charles Krinke", and we
>>> certainly don't want Charles to be constantly typing his password
>>> everytime he moves; the region needs to know that this user is already
>>> logged in to the system AND the region also needs to know that the agent
>>> that is representing this user is a legitimate agent.
>>>
>>> OK, so the part about being logged in is easy; the user server already
>>> knows that, to some approximation.
>>>
>>> However, the part about the agent being legitimate is a bit more tricky.
>>> Here's the bad thing that can happen: Charles logs in to OSgrid, and TPs
>>> to this intriguing region called "Sports Illuminated Swimming Suite
>>> Edition". That region happens to be up to no good. It grabs Charles
>>> current notion of identity (all the current identifiers we use), it
>>> crashes Charles' viewer so that the user server never knows about it,
>>> and proceeds to impersonate Charles using all those stolen identifiers;
>>> for example, it can go back to Charles's regions and erase them
>>> completely pretending to be Charles.
>>>
>>> So, what can we do to detect the legitimacy of agents?
>>>
>>> Having scratched my head over this, I came to the conclusion that the
>>> most promising element that can be used to identify agents is the
>>> Viewer's EndPoint. This is what happens down in the LLUDPServer (I'm
>>> sure something similar happens in other viewers' packet handlers):
>>>
>>> if (packet != null)
>>> {
>>> if (packet.Type == PacketType.UseCircuitCode)
>>> AddNewClient((UseCircuitCodePacket)packet, epSender,
>>> epProxy);
>>> else
>>> ProcessInPacket(packet, epSender);
>>> }
>>>
>>> The EndPoint epSender comes directly from the socket and I'm assuming it
>>> can't be faked, at least the IP part. Is this correct? This is a
>>> critical assumption.
>>>
>>> So, back to the "Sports Illuminated" scenario: that sim would then try
>>> to launch an agent at Charles' region. It can fake everything except
>>> being Charles' viewer machine. When Charles' region does that code
>>> above, it asks the User server for authentication of an agent with all
>>> those identifiers and the given EndPoint, and the User server tells back
>>> that Charles wasn't using that EndPoint to start with, so the
>>> authentication fails, and an alarm is rang.
>>>
>>> Thoughts?
>>>
>>> Crista
>>>
>>> Disclaimer: I'm not an expert in security, I'm just using my brain in
>>> context.
>>>
>>>
>>> _______________________________________________
>>> Opensim-dev mailing list
>>> Opensim-dev@lists.berlios.de
>>> https://lists.berlios.de/mailman/listinfo/opensim-dev
>>>
>>>
>>
>
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