[keycloak-dev] Authentication sessions & Action tokens PR

Mon May 15 08:14:37 EDT 2017

Hi Marek,

There are a lot of different ways how load balancers can create stickiness. They can use source or destination IP, they can use cookie insertion or cookie rewriting adding a route identifier to the response (this is similar to what you did), or they can also maintain sticky tables holding state like opaque session ids to map future requests to the right node.

There is some documentation how to do this in a simple way for nginx (https://www.nginx.com/products/session-persistence/), while (https://cbonte.github.io/haproxy-dconv/1.8/configuration.html#4.2-stick%20store-request) shows you can store arbitrary things to realize stickiness in HAProxy if you want to (e.g to act differently for requests coming from a proxy).

Anyways, I guess my point is that you can create session stickiness by just configuring your load balancer to use whatever mechanism you prefer. Ideally, Keycloak should not care and should not require a specific mechanism to be used. If I want a higher level of protection for my cluster more and not give out any information, I should be able to do this (at the cost of more work for the load balancers).

Of course, I am assuming Keycloak still works fine without session stickiness being configured correctly (just with reduced efficiency).

Best regards,
Sebastian

Mit freundlichen Grüßen / Best regards

 Sebastian Schuster

Engineering and Support (INST/ESY1) 
Bosch Software Innovations GmbH | Schöneberger Ufer 89-91 | 10785 Berlin | GERMANY | www.bosch-si.com
Tel. +49 30 726112-485 | Fax +49 30 726112-100 | Sebastian.Schuster at bosch-si.com

Sitz: Berlin, Registergericht: Amtsgericht Charlottenburg; HRB 148411 B 
Geschäftsführung: Dr.-Ing. Rainer Kallenbach, Michael Hahn 

-----Original Message-----
From: Marek Posolda [mailto:mposolda at redhat.com] 
Sent: Montag, 15. Mai 2017 13:02
To: Schuster Sebastian (INST/ESY1) <Sebastian.Schuster at bosch-si.com>; keycloak-dev at lists.jboss.org
Subject: Re: [keycloak-dev] Authentication sessions & Action tokens PR

On 15/05/17 10:20, Schuster Sebastian (INST/ESY1) wrote:
> Hi Marek,
>
> I guess using sticky sessions is fine. I was only referring to the 
> fact that the cookie content looked like it contains some route 
> identifier that is visible to the client. This way a client could find 
> out how many nodes are behind the load balancer or it could target 
> individual nodes. I think this would be a security issue and should be avoided by using just an opaque session id in the cookie. The load balancer will keep track of which node generated the session id and will route further requests accordingly.
Yes, it works this way. However AFAIK using the cookie to route requests is standard way, which most loadbalancers are using. Exposing some informations about underlying routes, and possibly count of cluster nodes, might be a price to pay.

It is possible to avoid it by:
- Avoid sticky sessions.
- I suppose some loadbalancers might have tools to somehow hide this (eg. encrypt the cookie), or track the mapping of the session-to-routes in some internal memory.

I must admin that I am not so experienced in what admins are typically doing. I am curious about your setup. Do you want to avoid sticky sessions at all or your loadbalancer has some other way to track them rather than through browser cookie? Which loadbalancer are you using?

Marek
>
> Best regards,
> Sebastian
>
>
> Mit freundlichen Grüßen / Best regards
>
>   Sebastian Schuster
>
> Engineering and Support (INST/ESY1)
> Bosch Software Innovations GmbH | Schöneberger Ufer 89-91 | 10785 
> Berlin | GERMANY | www.bosch-si.com Tel. +49 30 726112-485 | Fax +49 
> 30 726112-100 | Sebastian.Schuster at bosch-si.com
>
> Sitz: Berlin, Registergericht: Amtsgericht Charlottenburg; HRB 148411 
> B
> Geschäftsführung: Dr.-Ing. Rainer Kallenbach, Michael Hahn
>
>
>
>
> -----Original Message-----
> From: Marek Posolda [mailto:mposolda at redhat.com]
> Sent: Montag, 15. Mai 2017 09:47
> To: Schuster Sebastian (INST/ESY1) <Sebastian.Schuster at bosch-si.com>; 
> keycloak-dev at lists.jboss.org
> Subject: Re: [keycloak-dev] Authentication sessions & Action tokens PR
>
> Hi,
>
> we are adding some sticky session support, so this routeId is used by the loadbalancer to track to which cluster backend node it should forward the request. This is pretty much similar to what Wildfly is doing to track the session stickiness of servlet httpSessions. However I've added the SPI, so it would be possible to avoid adding the route to the cookie or use different strategy to add the route to the request.
> But without sticky sessions, you might have worse performance in cluster environment.
>
> Btv. do you want to avoid sticky sessions at all or your loadbalancer has some other way to track them rather than through browser cookie?
> Which loadbalancer are you using?
>
> Marek
>
>
> On 12/05/17 08:30, Schuster Sebastian (INST/ESY1) wrote:
>> Hi Marek,
>>
>> Is there a technical reason for including the routeid explicitely in the Cookie?
>> Normally, I would be reluctant to give out information about the 
>> setup behind the load balancer, like how many nodes the cluster consists of.
>>
>> Best regards,
>> Sebastian
>>
>> Mit freundlichen Grüßen / Best regards
>>
>>    Sebastian Schuster
>>
>> Engineering and Support (INST/ESY1)
>> Bosch Software Innovations GmbH | Schöneberger Ufer 89-91 | 10785 
>> Berlin | GERMANY | www.bosch-si.com Tel. +49 30 726112-485 | Fax +49
>> 30 726112-100 | Sebastian.Schuster at bosch-si.com
>>
>> Sitz: Berlin, Registergericht: Amtsgericht Charlottenburg; HRB 148411 
>> B
>> Geschäftsführung: Dr.-Ing. Rainer Kallenbach, Michael Hahn
>>
>>
>>
>>
>> -----Original Message-----
>> From: keycloak-dev-bounces at lists.jboss.org
>> [mailto:keycloak-dev-bounces at lists.jboss.org] On Behalf Of Marek 
>> Posolda
>> Sent: Donnerstag, 11. Mai 2017 22:33
>> To: keycloak-dev at lists.jboss.org
>> Subject: [keycloak-dev] Authentication sessions & Action tokens PR
>>
>> I've finally sent the PR
>> https://github.com/keycloak/keycloak/pull/4132
>> with the work for $subject. This includes the work by Hynek and me on Authentication sessions and action tokens. We finally managed to sort various kinks and have all tests passing.
>>
>> Some things and concepts were already discussed in some previous threads [1], [2], [3] and during presentations. So I won't repeat everything.
>> Just some highlights:
>>
>> - authenticationSession replaces the old ClientSessionModel. There is separate AuthenticationSessionProvider and separate infinispan cache "authenticationSessions" . This cache typicaly won't be replicated over all the datacenters, but instead it will rely on browser sticky sessions, hence browser will be redirected by loadbalancer to correct node in correct datacenter. So typicaly there won't be cross-dc communication needed during authentication.
>>
>> - I've added some support for sticky sessions already. In cluster environment, the authentication session cookie is created in the format like "sessionId.routeId" . For example "aabf27e6-7945-4d3a-a023-c1c64f7fdab4.node1". Pretty much same format like JSESSIONID cookie used as a cookie in classic java web applications. One side-effect of this PR is, that it also covers the support for running clustering tests on embedded undertow and from IDE.
>>
>> - Support for browser back/forward/refresh buttons was improved since my presentation last month. There are no browser redirects after the form submit, but instead there is a change of browser history through the javascript history.replaceState function. This pretty much removes all the POST requests from the browser history and helps with having good experience regarding browser buttons. In case that you have old browser not supporting this, the behaviour is same like before. Hence default browser "Page expired" page after clicking back from POST request (same behaviour like latest master). There are no additional redirects.
>>
>> - For action tokens, Hynek will likely add more. For quick summary, I can just mention that action token is JWT signed by realm secret key.
>> You can generate it in your authenticator or requiredActionProvider and send it somehow to user. Typically through email. Once user opens the actionToken URL from the email, it is processed on LoginActionsService endpoint, which provides most of the common basic functionality and verifications. LoginActionsService then finds the correct implementation of ActionTokenHandler, which is separate SPI. This allows to specify the details how can be actionToken handled, whether it's single use or not etc. There is support for the scenario if user opened link in the same browser when he started authenticationSession or in different browser etc.
>>
>> - Regarding PR, I've tried to squash the commits a bit. However PR still consists of more commits to track at least what was done by me and what by Hynek. Do you think it is the issue to have more commits in the PR?
>>
>> - This is hopefully the bigest task for the cross-dc support. My hope is that PR can be reviewed and merged soon as the work is more and more unsynced with the latest master and rebasing is a bit of pain. But I understand that this will require time. There is change in 324 files :) There are still a lot things to cover for cross-dc, but I think those can be done in smaller pieces and commit more often.
>>
>> [1]
>> http://lists.jboss.org/pipermail/keycloak-dev/2017-March/009066.html
>> [2]
>> http://lists.jboss.org/pipermail/keycloak-dev/2017-March/009121.html
>> [3]
>> http://lists.jboss.org/pipermail/keycloak-dev/2017-March/009125.html
>>
>> Marek
>>
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