Hyrax - User Identification (Authentication): Difference between revisions

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https://wiki.earthdata.nasa.gov/display/URSFOUR/Apache+URS+Authentication+Module
https://wiki.earthdata.nasa.gov/display/URSFOUR/Apache+URS+Authentication+Module


(NB: The instructions are clear and complete but you have to be a registered URS user with permissions to access that page in order to read it.)
(NB: The instructions are clear and complete but you have to be a registered URS user with permissions to access that page in order to read it. Also note that the apxs tool used to build an apache module is part of the ''httpd-devel'' package and won't be available if you don't have that package installed.)


Once I had it installed all that was need was to create the file ''/etc/httpd/conf.d/urs.conf'' and add the following content:
Once I had it installed all that was need was to create the file ''/etc/httpd/conf.d/urs.conf'' and add the following content:

Revision as of 22:24, 5 December 2014


Overview

This document is intended to help those that have been asked to deploy Hyrax into an environment where authentication of users is required. In many such cases Hyrax will be integrated into an existing instance of the Apache Web server (httpd) where authentication services are already configured and in use. In other cases people will be setting up a standalone instance of Tomcat and will be needing to configure it to use one of the supported authentication services. This document means to address both situations.

Terms

Authentication
This is the process of confirming the identity of the user. The end result is a User ID (uid or UID) which may be accessed by the software components via (both?) the Apache API (mod_*) and the Java ServletAPI (Tomcat servlets) used to trigger authorization policy chains or may be logged along with relevant request information.
Identity Provider (IdP)
Also known as an Identity Assertion Provider, an Identity Provider (IdP) is a service that provides authentication and identity information services. An IdP is a kind of provider that creates, maintains, and manages identity information for principals and provides principal authentication to other service providers within a federation, such as with web browser profiles.
Service Provider (SP)
A Service Provider (SP) is a Web Service that utilizes an IdP service to determine the identity of it's users. Or more broadly, a role donned by a system entity where the system entity provides services to principals or other system entities.

With respect to this document Hyrax/Tomcat, and Hyrax/Tomcat/Apache each become part of an SP through the installation and configuration of software components such as mod_shib (shibboleth) .

See Service Providers, Identity Providers & Security Token Services explained for more.

Apache httpd Authentication Services Configuration

There are many authentication methods available for use with our friend httpd. Each of them may have a unique installation and configuration activity. There are some common changes that must be made to the Tomcat configuration regardless of the authentication method employed by Apache. We'll cover those first and the examine LDAP, Shibboleth, and NASA URS IdP configurations for Apache httpd.

NB
If you are deploying Hyrax with an existing Apache service then it is likely that all you have to do is configure httpd and Tomcat to work together and define and then define a security constraint for httpd that enforces a login requirement (valid-user) for Hyrax.


First: Configure Apache httpd and Tomcat to work together

In this part we configure Tomcat and Apache httpd to work together so that httpd can provide proxy and authentication services for Hyrax.

Configure Apache

In /etc/httpd/conf.d create a file called hyrax.conf . Edit the file and add following: 

<Proxy *>
    AddDefaultCharset Off
    Order deny,allow
    Allow from all
</Proxy>
 
ProxyPass /opendap ajp://localhost:8009/opendap
ProxyPassReverse /opendap ajp://localhost:8009/opendap

This will expose the web application "opendap" (aka Hyrax) through Apache. Make sure that the AJP URLs both point to your deployment of Hyrax.

Configure Tomcat (Hyrax)

The primary result of the Apache authentication (the uid string) must be correctly transmitted to Tomcat. On the Tomcat side we have to open the way for this by configuring a AJP Connector object. This is done by editing the file:

$CATALINA_HOME/conf/server.xml

Edit the server.xml file, and find the AJP Connector element on port 8009. It should look something like this: 

<Connector port="8009" protocol="AJP/1.3" />

This line may be "commented out," with <!-- on a line before and --> on a line after. If so, remove those lines. If you cannot find the AJP connector element, simply create it from the code above.

  • In order to receive authentication information from Apache, you must disable Tomcat's native authentication. Set the tomcatAuthentication attribute to "false" - see below for an example.
  • If your Apache web server is using SSL/HTTPS (and it should be), you need to tell Tomcat about that fact so that it can construct internal URLs correctly. Set the scheme attribute to "https" and the proxyPort attribute to "443" - see below for an example.
  • For increased security, disable access to the connector from anywhere but the local system. Set the address attribute to "127.0.0.1" - see below for an example.

When you are finished making changes, your connector should look something like this: 

    <Connector 
        port="8009" 
        protocol="AJP/1.3" 
        redirectPort="443" 
        scheme="https"
        address="127.0.0.1" 
        enableLookups="false"  
        tomcatAuthentication="false" 
        />
port
The Connector will listen on port 8009.
protocol
The protocol is AJP/1.3.
redirectPort
Secure redirects to port 443 which is the nominal Apache HTTPS port.
scheme
Ensure that scheme is HTTPS
address
The loopback address (127.0.0.1) ensures that only local requests for the connection will be serviced.
enableLookups
A value of true enable DNS look ups for Tomcat. This means that web applications (like Hyrax) that will see the client system as a host name and not an IP address. Set this to false to improve performance.
tomcatAuthentication
A value of false will allow the Tomcat engine to receive authentication information (the uid and in some cases other attributes) from Apache httpd. A value of true will cause Tomcat to ignore Apache authentication results in favor of it's own.

Restart Tomcat to load the new configuration. Now the Tomcat web applications like Hyrax should see all of the Apache authentication attributes. (These can be retrieved programmatically in the Java sServlet API by using HttpServletRequest.getRemoteUser() or HttpServletRequest.getAttribute("ATTRIBUTE NAME"). Note that HttpServletRequest.getAttributeNames() may not list all available attributes – you must request each attribute individually by name.)

Second: Configure Apache httpd to authenticate

Once Tomcat and Apache httpd are working together all that remains is to configure a security restraint on the Hyrax web application and specify the authentication mechanism which is to used to identify the user.

While the details of the Apache security constraints differ somewhat from one IdP to the next what is consistent is that you will need to define a security constraint on Hyrax inside the chain of httpd.conf files. The most simple example, that you want all users of the Hyrax instance to be authenticated, might look something like this: 

<Location /opendap>
  AuthType YourFavoriteAuthTypeHere
  require valid-user
</Location>

Where the require valid-user attribute makes the requirement that all accessors be authenticated and YourFavoriteAuthTypeHere would be something like Basic, UrsOAuth2 or shibboteth.

Complete examples for LDAP, URS/OAuth2, and Shibboleth IdPs are presented in the following sections.

LDAP (mod_ldap, mod_authnz_ldap)

NB: Sections Configure Apache To Proxy Tomcat and Configure Tomcat (Hyrax) must be completed prior to completion of this section

In order to get Apache httpd to use LDAP authentication you will have configure an Apache security constraint on the Hyrax web application. For this example we will configure Apache to utilize the Forum Systems public LDAP server

  • All user passwords are password.
  • Groups and Users:
    • mathematicians
      • riemann
      • gauss
      • euler
      • euclid
    • scientists
      • einstein
      • newton
      • galieleo
      • tesla


Create and edit the file /etc/httpd/conf.d/ldap.conf.

Add the following at the end of the file: 

# You may need to uncomment these two lines...
# LoadModule ldap_module modules/mod_ldap.so
# LoadModule authnz_ldap_module modules/mod_authnz_ldap.so

# You may want to comment out this line once you have it working.
LogLevel debug

<Location /opendap >
   Order deny,allow
   Deny from all
   AuthType Basic
   AuthName "Forum Systems Public LDAP Server-  Login with user id"
   AuthBasicProvider ldap
   AuthzLDAPAuthoritative off
   AuthLDAPURL ldap://ldap.forumsys.com:389/dc=example,dc=com
   AuthLDAPBindDN "cn=read-only-admin,dc=example,dc=com"
   AuthLDAPBindPassword password
   AuthLDAPGroupAttributeIsDN off
   ErrorDocument 401 "Please use your username and password to login into this Hyrax server"
   Require valid-user
   Satisfy any
</Location>

Restart Apache httpd and you should now need to authenticate to access anything in /opendap

Shibboleth (mod_shib)

NB: Sections Configure Apache To Proxy Tomcat and Configure Tomcat (Hyrax) must be completed prior to completion of this section


The Shibboleth wiki provides excellent documentation on how to get Shibboleth authentication services working with Tomcat. This is primarily an Apache httpd activity.

Basically you need to follow the instructions for a Native Java Install and remember - Hyrax does not use either Spring or Grails.

Installation

The logical starting point for this is with the Native Java SP Installation:

But as far as the organization of the work is concerned it is really the last page you need to process, as it will send you off to do a platform dependent Shibboleth Native Service Provider for Apache installation which needs to be completed, working, and configured before you'll return to the Native Java SP Installation to enable the part where Tomcat and mod_shib pass authenticated user information into Tomcat.

The document path on the Natvie Java Install wiki page will send you off to do Shibboleth Native Service Provider installation which is platform dependent:


Return to the Native Java SP Installation and complete the instructions there.

Configuration

Once the SP installation is completed go to the Native SP Configuration page:

Read that page and then follow the link to the instructions for Apache:

Follow those instructions.


The Shibboleth instructions should have had you add something like this: 

<Location /opendap>
  AuthType shibboleth
  ShibRequestSetting requireSession 1
  require valid-user
</Location>

to httpd.conf. This will require users to authenticate to access any part of Hyrax which may be exactly what you want. If you want more fine grained control you may want use multiple Location elements with different require attributes. For example: 

<Location /opendap>
  AuthType shibboleth
  ShibCompatWith24 On
  require shibboleth
</Location>
<Location /opendap/AVHRR>
  AuthType shibboleth
  ShibCompatWith24 On
  ShibRequestSetting requireSession 1
  require valid-user
</Location>
</apache>

In this example the first Location establishes Shibboleth as the authentication tool for the entire /opendap application path, and enables the Shibboleth module over the entire Hyrax Server.

  • Since there is no ShibRequestSetting requireSession 1 line it does not require a user to be logged in order to access the path.
  • The require shibboleth command activates mod_shib for all of Hyrax.

The second Location states that only valid-users may have access "/opendap/AVHRR" URL path.

  • The require valid-user command requires user authentication.
  • The AuthType command is set to shibboleth so mod_shib will be called upon to perform the authentication.

For more examples and better understanding see the Apache Configuration section of the Shibboleth wiki.

URS OAuth2 (mod_auth_urs)

NB: Sections Configure Apache To Proxy Tomcat and Configure Tomcat (Hyrax) must be completed prior to completion of this section

The instructions for configuring the Apache module mod_auth_urs can be found here:

https://wiki.earthdata.nasa.gov/display/URSFOUR/Apache+URS+Authentication+Module

(NB: The instructions are clear and complete but you have to be a registered URS user with permissions to access that page in order to read it. Also note that the apxs tool used to build an apache module is part of the httpd-devel package and won't be available if you don't have that package installed.)

Once I had it installed all that was need was to create the file /etc/httpd/conf.d/urs.conf and add the following content: 

# Load the URS module
LoadModule auth_urs_module    modules/mod_auth_urs.so
#
# Enable Debugging
LogLevel debug
#
# START - URS module configuration
# The directory where session data will be stored
#
UrsSessionStorePath /var/tmp/urs/session
# The address of the authentication server
#
UrsAuthServer       https://uat.urs.earthdata.nasa.gov
# The authentication endpoint
#
UrsAuthPath          /oauth/authorize
# The token exchange endpoint
#
UrsTokenPath         /oauth/token
#
#
# END - URS module configuration

# Place a URS security constraint on the Hyrax service
<Location /opendap >

    AuthType UrsOAuth2
    AuthName "URS_AuthTest"
    Require valid-user

    UrsAuthGroup       HyraxDataServer
    UrsClientId        04xHKVaNdYNzCBG6KB7-Ig
    UrsAuthCode        MDR4SEtWYU5kWU56Q0JHNktCNy1JZzpKSEdqa2hmZzY3OA==
    UrsRedirectUrl     https://54.172.97.47/opendap/login
    UrsIdleTimeout     600
    UrsActiveTimeout   36000
    UrsIPCheckOctets   2
    UrsUserProfileEnv  uid              URS_USER
    UrsUserProfileEnv  email_address    URS_EMAIL
    UrsUserProfileEnv  first_name       URS_FIRST
    UrsUserProfileEnv  last_name        URS_LAST

    UrsAccessErrorUrl  /urs403.html

</Location>

Assuming that the AJP proxy for Tomcat is already done simply restart Tomcat and access Hyrax with your URS credentials.

Tomcat Authentication Services Configuration

Tomcat provides a number of authentication Realm implementations including the JNDIRealm which provides LDAP SP services for Tomcat. There is currently no Shibboleth realm implementation for Tomcat, and it's an open question for the author if there could be one for Shibboleth or OAuth2 given the way that these protocols utilize 302 redirects away from the origin service.

LDAP

The instructions for configuring Tomcat to perform LDAP authentication are located here. It is clearly a benefit if you understand a fair bit about LDAP before you undertake this.

Here is an example of how to configure Tomcat to use LDAP authentication.

In this example we configure a Tomcat JNDI realm to use the public LDAP service provided by ForumSys.

In the server.xml file we added a JNDI Realm element: 

<Realm 
    className="org.apache.catalina.realm.JNDIRealm" 
    connectionURL="ldap://ldap.forumsys.com:389"
    connectionName="cn=read-only-admin,dc=example,dc=com"
    connectionPassword="password"
    userPattern="uid={0},dc=example,dc=com" 
    roleBase="dc=example,dc=com" 
    roleName="ou" 
    roleSearch="(uniqueMember={0})"
/>

Configured to work with the Forum Systems test LDAP server.

Then in the opendap web application we added the following security constraint to the WEB-INF/web.xml file: 

<security-constraint>
    <web-resource-collection>
         <web-resource-name>Hyrax Server</web-resource-name>
         <url-pattern>/*</url-pattern>
    </web-resource-collection>
    <auth-constraint>
         <role-name>user</role-name>
    </auth-constraint>
   
    <user-data-constraint>
         <!-- this ensures that all efforts to access the admin interface nd resources must use HTTPS -->
         <transport-guarantee>CONFIDENTIAL</transport-guarantee>
    </user-data-constraint>
</security-constraint>


No changes were made to the $CATALINA_HOME/conf/tomcat_users.xml file.

Shibboleth

There is no actual Shibboleth integration with Tomcat beyond what is provided by running the Apache httpd module mod_shib and connecting Tomcat to httpd using AJP as described in the Apache/Shibboleth section on this page.

URS OAuth2

There is no actual URS integration with Tomcat beyond what is provided by running the Apache httpd module mod_auth_urs and connecting Tomcat to httpd using AJP as described in the Apache/URS section on this page.

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