[Opensim-dev] [REX] [Fwd: User Authentication]

Tue Feb 24 00:19:31 UTC 2009

The only thing that concerns me about using the endpoint for
authentication, is it's UDP.  Anyone with access to raw sockets your
IP address, UUID and circuit code, session ID, and SecureSessionId
could pretend to be you.   I would suggest a better way to validate
the endpoint would be to verify the IP address on the Seed caps call
parhaps.  In theory, the initial seed cap would be gotten by the user
server from the appropriate sim and forwarded to the user over SSL.
There may also be some checking potential in that the user server
could post the IP address that the simulator should expect a
connection from.   Then when the seed cap is requested, the simulator
could check the IP with the User Server.   The other aspect of this is
securely ensuring that an avatar can only be in one place(simulator)
at the same time.  This could be done with some careful session
locking.

Best Regards

Teravus

On 2/23/09, Charles Krinke <cfk at pacbell.net> wrote:
>
> Well, I suppose that since we can discern which viewer logs in via the
> UserServer, we can allow additional features for some viewers that dont
> exist for others.
>
> Dont know if that simplifies or complicates the problem, however.
>
> Charles
>
> ________________________________
> From: Diva Canto <diva at metaverseink.com>
> To: opensim-dev at lists.berlios.de
> Sent: Monday, February 23, 2009 3:52:29 PM
>
> Subject: Re: [Opensim-dev] [REX] [Fwd: User Authentication]
>
> "However, this would currently have to happen purely as communication
> between backend services since we can't change the viewer."
>
> This doesn't solve the man-in-the-middle problem in OSGrid itself, which
> needs to be solved too, urgently.
> I think my proposal does.
>
> Crista
>
>
> Hurliman, John wrote:
> A RADIUS server is a solution to the problem of authentication. OpenID is a
> solution for federated identity, and plays nicely with any authentication
> solution you want to use. I think the description of this particular problem
> is closer to identity verification across administrative domains than
> defining a common login protocol, so the OpenID + token systems sound like
> the right approach. However, this would currently have to happen purely as
> communication between backend services since we can't change the viewer. A
> possible flow might be:
>
> (OSGrid)->(UCI) "User
> http://www.osgrid.org/users/Charles_Krinke is teleporting
> to you. His token is abcdef"
> (UCI)->(http://www.osgrid.org/users/Charles_Krinke) "I
> have the token abcdef, is that a valid session token for Charles?"
> (UCI)<-(http://www.osgrid.org/users/Charles_Krinke) "Yes it
> is"
> (OSGrid)<-(UCI) "That worked, thanks. Teleport is finished"
>
> Notice that Charles happens to have his identity at OSGrid, but that's not a
> requirement of the exchange. It could just as easily been an identity from
> another grid, which will be useful for teleporting from UCI to ScienceSim.
>
> John
>
>
> -----Original Message-----
> From: opensim-dev-bounces at lists.berlios.de
> [mailto:opensim-dev-
> bounces at lists.berlios.de] On Behalf Of Mark Malewski
> Sent: Monday, February 23, 2009 3:04 PM
> To: Opensim-dev at lists.berlios.de
Subject: Re: [Opensim-dev] [REX] [Fwd: User
> Authentication]

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 (hostname at 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:
>
> hostname at 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.malewski at gmail.com>
wrote:

 On Mon,
> Feb 23, 2009 at 3:28 PM, Mark Malewski
<mark.malewski at 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 <http://somedomain.com/>
> \username at 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
<antont at 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.Krinke at osgrid.org is, indeed,
>  representing Charles.Krinke at 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 <http://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 at lists.berlios.de
> https://lists.berlios.de/mailman/listinfo/opensim-dev

>
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