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From Jeff Genender <>
Subject Re: Security Role Mapping & Authentication
Date Wed, 03 Aug 2005 07:35:35 GMT

Aaron Mulder wrote:
> Jeff,
> 	I don't understand what you're saying about a realm GBean, and I'm
> a little sketchy on the appName.  

Sorry about that...I was speaking Tomcat speak...and it can get very 
hairy at times.  I was describing the Tomcat JAAS implementation and how 
it works...its very confusing.

> Can I explain what I'm looking for and
> then you can tell me if you think this is reasonable and whether it's in
> place now?

Its basically in place now...but there is one small issue...see below.

>  - If you have a web app that uses a login (HTTP Basic, Form-based, etc.),
>    then the server needs to use some "security realm" to authenticate the
>    user name and password you provide.
>  - I would like that to always be a Geronimo SecurityRealm, regardless of
>    whether you're using Tomcat or Jetty or what.
>  - I would like that to always be the Geronimo security realm whose name 
>    is listed in the <security-realm-name> elements of geronimo-web.xml (if 
>    geronimo-web.xml was provided and if it has that element).
>  - I don't want you to have to declare *any* GBeans that are Tomcat or
>    Jetty specific.  You must have declared the GenericSecurityRealm GBean
>    with the proper name, of course.

This will be a small problem.  The adapter is the RealmGBean.  If I 
declare the RealmGBean and attach it to the Engine (i.e. already 
configured in the j2ee-server-plan.xml), then the Engine Gbean's "name" 
initParam *must* match the Geronimo Realm you created - this is a Tomcat 
requirement.  Thus all contexts (and hosts) underneath the engine will 
use that realm by that name.  In otherwords...the RealmGBean adapter is 
inherited by all Hosts and Contexts that are children to the Engine (the 
Tomcat Server).

Now, if I declare a RealmGBean in the geronimo-web.xml, it will 
automagically be attached to that web context...and will override the 
Engine version for that particular context.  I am allowing the 
<security-realm-name> to be used.

So...the following would be added to your geronimo-web.xml example below:

<container-config container="Tomcat">
    <config-param name="TomcatRealm">TomcatJAASRealm</config-param>

<gbean name="TomcatJAASRealm"
     <attribute name="initParams">

The real addition here is the container-config and the Gbean.

If this is a problem and we truly want this to be seemless for Jetty and 
Tomcat, then I really recommend we go back to the Sun paradigm of the 
login.config file and name the realms like the web application context 
roots or default names.

> 	I assume Tomcat requires some sort of adapter to make a Geronimo
> SecurityRealm look like a "Tomcat Security Realm".  I'm speculating this
> is the "RealmGBean" you mention, but I don't know.  I would like to
> automatically create that and set it on Tomcat during the deployment
> process, so the user doesn't need to specifically declare it. 
> So, for
> example, this would be a totally sufficient geornimo-web.xml if you want
> to refer to the default security realm configured in Geronimo (named
> geronimo-properties-realm, of type GenericSecurityRealm, and configured in
> j2ee-server-plan.xml):
> <web-app
>     xmlns=""
>     xmlns:naming=""
>     configId="MyConfigName"
>     parentId="ParentConfigName">
>   <security-realm-name>geronimo-properties-realm</security-realm-name>
>   <security>
>     <role-mappings>
>       <role name="AppUsers">
>         <realm name="geronimo-properties-realm">
>           <principal class=""
>            name="system" />
>         </realm>
>       </role>
>     </role-mappings>
>   </security>
> </web-app>
> 	So this says, "when any user logs in, resolve their username and
> password against the properties file var/security/, and if
> their username is 'system' then add them to the J2EE role 'AppUsers'".
> 	If we implement what I've described above, then I believe this
> same deployment plan should work with the same results for both Tomcat and
> Jetty (and it doesn't have any settings or GBeans in it specific to either
> Tomcat or Jetty).
> Thanks,
> 	Aaron
> On Wed, 3 Aug 2005, Jeff Genender wrote:
>>Ok..even though I still stand by what I said below (and want to get some 
>>feedback on this), I figured, it surely wouldn't hurt to allow the 
>><security-realm-name> be an override for the appName of the Tomcat 
>>JAASRealm.  If its not specified, it will default to the standard 
>>methodology of how Tomcat looks for a realm (by name of the path/context 
>>or Host or Engine depending upon where the Realm was declared).  One 
>>caveat...if you want the Realm to use the context's 
>><security-realm-name>, you must have a RealmGBean applied at the context 
>>level in the geronimo-web.xml.  If you do will get the 
>>following log:
>>WARN: security-realm-name was specified but no RealmGBean was configured 
>>for this context.  Ignoring security-realm-name.
>>and it will thus default to the Tomcat standard realm naming conventions 
>>(i.e. the inherited Host or Engine name at which the Realm was supplied 
>>- Engine by default).
>>So...its coded, unit tested, and checked in.
>>Jeff Genender wrote:
>>>Correct, Tomcat does not use the <security-realm-name> element from the

>>>How it works is...
>>>The Tomcat realms take the name of the object it is associated with. 
>>>Tomcat objects inherit Realms from top down.  If a Realm is associated 
>>>with an Engine, then the Host(s) and Context(s) inherit that realm. The 
>>>same goes for Hosts...if its associated with that host, then all 
>>>Contexts under that Host inherits the Realm.   Here is the example...
>>>There is typically a geronimo realm GBean that is created...lets use the 
>>>example of the one in the tomcat-config.xml.  Notice the realmName 
>>>attribute is "Geronimo".
>>>Then a TomcatRealm is attached either the Engine, Host, or Context 
>>>levels.  In this instance we have the TomcatRealm attached to the server 
>>>(i.e. the Engine) Notice the Engine object in tomcat-config.xml has a 
>>>name parameter of "Geronimo".  All Contexts under that Engine will 
>>>associate itself with the "Geronimo" realm name.  So this is Server-wide.
>>>If I wish to change a Context to specifically use its own specific 
>>>realm, its name is the context root/path name. So say I have created an 
>>>application that has a context root of "testme", then I can attach a 
>>>Realm object to it, and this Realm object will expect to find a realm 
>>>called "testme".
>>>This is how standard tomcat realms work, and it is because normally, 
>>>J2EE/JAAS uses a login.config file, where we declare our realms with 
>>>login modules like this:
>>><name used by application to refer to this entry> {
>>>    <LoginModule> <flag> <LoginModule options>;
>>>    <optional additional LoginModules, flags and options>;
>>>    };
>>>(See for more info)
>>>In Geronimo, since we don't use a login.config, instead, we wire these 
>>>up via 2 GBeans...a realm and a loginmodule.  The application name 
>>>really becomes the realm name in our world.  So to keep in line with the 
>>>login.config configuration, we use the realmName of the 
>>>GenericSecurityRealm matched up with the application name (or path of 
>>>our Context).
>>>It would not be too difficult to use the <security-realm-name> as an 
>>>override at this point, but Tomcat has stated that setName() on the 
>>>Realms is deprecated and thus will disappear in the future.  This does 
>>>not preclude us rewriting the Realms, but it would break compatibility 
>>>with the slew of Realm objects offered by Tomcat in the future.
>>>I would suggest we examine why we use <security-realm-name> and why not

>>>follow the application name paradigm that appears to be a standard.
>>>Aaron Mulder wrote:
>>>>    So in web apps, the developer provides a list of roles in web.xml,
>>>>and then we let you map any principals from any Geronimo security realms
>>>>to the J2EE roles using the <security> element in geronimo-web.xml 
>>>>(it's quite possible to allow principals from multiple realms).
>>>>    However, on top of that, there's a <security-realm-name> element

>>>>in geronimo-web.xml, which appears to be used by Jetty and not 
>>>>Tomcat.  This appears to be used to set the JettyJAASRealm on the 
>>>>JettyWebAppContext (see
>>>>    I'm assuming that when you log in to Jetty, it authenticates you 
>>>>against the security realm named in the <security-realm-name> element,

>>>>and then authorizes you against the mappings performed in the 
>>>><security> element.  So logically, it wouldn't help you to include 
>>>>principals from any other realm in the <security> element, but we 
>>>>don't enforce that in the schemas.
>>>>    If that's true, then what realm does Tomcat authenticate against?  
>>>>And what realm do EJBs authenticate against?  Both Tomcat and EJBs appear
>>>>to only use the <security> element (Tomcat ignores the
>>>><security-realm-name> element AFAICT and openejb-jar.xml doesn't have
>>>>    Aaron

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