THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
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| JAX-RS |
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| Kerberos |
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| Support |
| Table of Contents |
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Introduction
Please see MIT Kerberos Tutorial for a good introduction to Kerberos.
The Windows guide as well as this Wikipedia page are also worth checking.
Setup
Unix
1. Install the packages
> sudo apt-get install krb5-kdc krb5-admin-server
During the installation enter "localhost" as the host name for Kerberos servers (unless you have more specific host names to enter) and set a default realm, example, "MYCOMPANY.COM". Follow the 1.2 step from this blog entry to get this default realm set up properly.
2. Create principals
From the step 1.3 at this blog entry:
2.1 Create master key:
> sudo kdb5_util create -s
2.2 Create user and service principals
> sudo kadmin.local
followed by
> addprinc alice
> addprinc HTTP/localhost
where 'HTTP/localhost' is the typical service principal name used in the Negotiate scheme, replace 'localhost' if needed.
Add more user and service principals too as required.
3 Start KDC
> sudo krb5kdc
4. Create an optional ticket cache
> klist
returns an empty response
> kinit alice
> klist
confirms a TGT for 'alice' is in the cache.
2.4 Create keytabs
When keytabs are available, the principal password does not have to be specified in the login configuration.
Please follow the step 1.4 from this blog entry.
Note, creating a keytab actually resets an original principal password, example, after creating a keytab for 'alice' one would not be able to use the original password (TODO: apparently this can be restored - find out how). Thus, if you'd like to experiment with keytabs then you may want to have few user and service principals created, with only selected principals using keytabs.
Windows
Please check the relevant Windows configuration guide such as this one.
HTTP Negotiate scheme
'Negotiate' authentication scheme is used to pass Kerberos service tickets over HTTP.
Example:
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Authorization: Negotiate "the encrypted service ticket"
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GSS API
Please see this GSS API tutorial as well as check this blog for a number of GSS API examples. Understanding GSS API may help when the way CXF Kerberos handlers work needs to be customized or when the available GSS credentials created outside of CXF need to be made available to CXF (for the credential delegation).
JAAS Kerberos Module Configuration
com.sun.security.auth.module.Krb5LoginModule is typically used to login to Kerberos servers.
Client configuration
HTTPConduit
Please see this page for the information about Spnego/Kerberos HTTPConduit client support.
Interceptor
org.apache.cxf.jaxrs.security.KerberosAuthOutInterceptor
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can
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be
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used
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as
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an
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alternative
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to
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configuring
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HTTPConduit.
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KerberosAuthOutInterceptor
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and
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the
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HTTPConduit
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Spnego
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handler
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share
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the
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same
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base
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code.
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Having
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HTTPConduit
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configuration
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can
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be
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enough
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in
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many
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cases
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especially
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when
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SSL
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is
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also
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being
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setup
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at
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the
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conduit
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level.
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Using
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the
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interceptor
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can
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be
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handy
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when
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testing
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as
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well
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as
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when
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setting
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few
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extra
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properties
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which
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is
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not
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easy
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to
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set
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up
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at
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the
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generic
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HTTP
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Conduit
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Authorization
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Policy
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level.
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The
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interceptor
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properties
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are
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explained
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in
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the
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following
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sub-sections
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Authorization
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Policy
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As
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explained
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on
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,
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Authorization
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Policy
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typically
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needs
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to
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have
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its
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type
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set
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to
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"Negotiate"
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and
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its
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"authorization"
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property
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set
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to
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the
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name
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of
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the
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JAAS
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context.
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AuthorizationPolicy
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is
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set
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as
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a
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"policy"
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property
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on
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the
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interceptor,
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example:
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{code:java} WebClient wc = WebClient.create("http://localhost:" + PORT + "/bookstore/books/123"); KerberosAuthOutInterceptor kbInterceptor = new KerberosAuthOutInterceptor(); AuthorizationPolicy policy = new AuthorizationPolicy(); policy.setAuthorizationType(HttpAuthHeader.AUTH_TYPE_NEGOTIATE); policy.setAuthorization("KerberosClientKeyTab"); kbInterceptor.setPolicy(policy); WebClient.getConfig(wc).getOutInterceptors().add(kbInterceptor); Book b = wc.get(Book.class); {code} h3. Configuring the service principal name By default, the service principal name is calculated by concatenating "HTTP", "/" and the name of the target host, example, when invoking on |
In this example, the KerberosClientKeyTab policy is used which links to the available keytab; otherwise AuthorizationPolicy 'UserName' and 'Password' properties would most likely have to be set too (with the possible exceptions on Windows)
Configuring the service principal name
Service principal identifies a target service.
By default, the service principal name is calculated by concatenating "HTTP", "/" and the name of the target host, example, when invoking on "http://localhost:8080/services",
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the
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service
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principal
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name
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is
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set
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to
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"HTTP/localhost".
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The
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"servicePrincipalName"
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and
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"realm"
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properties
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can
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be
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used
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to
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customize
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it,
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example,
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setting
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"servicePrincipalName"
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to
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"HTTP/www.mycompany.com"
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and
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realm
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to
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"services.org"
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will
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result
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in
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the
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"HTTP/www.mycompany.com@services.org"
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service
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principal
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name
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being used.
When the "servicePrincipalName" is not specified, the target host from the provided endpoint URL is used to construct one as-is. To perform canonicalization of this hostname (e.g. if a CNAME record host.example.com points to an A record host-x.example.com, then use "host-x.example.com" when constructing the servicePrincipalName), the "useCanonicalHostname" property can be set to "true".
Using JAAS Configuration
Both HTTPConduit and interceptor handlers need a "java.security.auth.login.config"
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system
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property
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set
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up.
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This
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property
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needs
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to
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point
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to
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the
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file
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containing
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the
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configuration
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of
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the
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specific
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Kerberos
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login
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module.
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Instead
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of
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setting
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this
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system
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property
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and
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maintaining
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a
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configuration
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file,
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one
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might
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want
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to
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use
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an
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implementation
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of
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javax.security.auth.login.Configuration
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and
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set
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it
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on
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the
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interceptor
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as
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a
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"loginConfig"
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property.
How to avoid setting username and password properties
Typically, one may have to set AuthorizationPolicy UserName and Password properties for the Kerberos login module to authenticate the user.
The next option is to create a keytab as noted in the Setup section, which will let one to avoid specifying a password property.
Finally, if the user actually owns the Java process which runs the code then no username and password properties have to be provided, assuming the Kerberos login configuration has 'useTicketCache' and possibly 'renewTGT' properties set to "true"
Server configuration
org.apache.cxf.jaxrs.security.KerberosAuthenticationFilter
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can
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be
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used
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to
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protected
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JAX-RS
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endpoints
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and
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enforce
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that
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a
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Negotiate
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authentication
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scheme
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is
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used
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by
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clients,
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example:
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{code:xml} <bean id="kerberosFilter" class="org.apache.cxf.jaxrs.security.KerberosAuthenticationFilter"> <property name="loginContextName" value="KerberosServiceKeyTab"/> </bean> <jaxrs:server> <jaxrs:serviceBeans> <bean class="org.mycompany.MyCompanyResource"/> </jaxrs:serviceBeans> <jaxrs:providers> <ref bean="kerberosFilter"/> </jaxrs:providers> </jaxrs:server> {code} |
KerberosAuthenticationFilter
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will
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set
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a
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CXF
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on
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the
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current
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message
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if
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the
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authentication
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has
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been
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successful.
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This
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SecurityContext
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will
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return
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an
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instance
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of
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KerberosAuthenticationFilter$KerberosPrincipal,
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this
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Principal
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will
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return
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a
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'simple'
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and
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'kerberos'
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source
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principal
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names,
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example,
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given
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"HTTP/localhost@myrealm.com",
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Principal#getName
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will
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return
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"HTTP/localhost",
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and
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KerberosPrincipal#getKerberosName
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will
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return
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"HTTP/localhost@myrealm.com".
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Service
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principal
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name
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and
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JAAS
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Configuration
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Service
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principal
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name
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and
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JAAS
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Configuration
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can
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be
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optionally
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set
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up
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the
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same
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way
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they
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can
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be
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with
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KerberosAuthOutInterceptor,
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using
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'servicePrincipalName'
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+
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'realm'
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and
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"loginConfig"
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properties.
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CallbackHandler
javax.security.auth.callback.CallbackHandler
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needs
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to
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be
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registered
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if
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no
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Kerberos
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key
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tabs
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are
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used,
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here
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is
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an
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example
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of
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setting
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it
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up
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from
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Java:
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{code:java} public class TestResource { public static void main(String[] args) { JAXRSServerFactoryBean sf = new JAXRSServerFactoryBean(); sf.setResourceClasses(BookStore.class); KerberosAuthenticationFilter filter = new KerberosAuthenticationFilter(); filter.setLoginContextName("KerberosServer"); CallbackHandler handler = new org.apache.cxf.interceptor.security.NamePasswordCallbackHandler("HTTP/localhost", "http"); filter.setCallbackHandler(handler); //filter.setLoginContextName("KerberosServerKeyTab"); //filter.setServicePrincipalName("HTTP/ktab"); sf.setProvider(filter); sf.setAddress("http://localhost:" + PORT + "/"); sf.create(); } } {code} h1. Credential Delegation Please see this [section|http://cxf.apache.org/docs/client-http-transport-including-ssl-support.html#ClientHTTPTransport%28includingSSLsupport%29-CredentialDelegation] on the way client-side credential delegation can be both enabled and implemented at the HTTP conduit level. Note that if you have a JAX-RS KerberosAuthenticationFilter protecting the endpoints, then the filter will have an |
In this example, the KerberosServer policy is used.
Credential Delegation
Please see this section on the way client-side credential delegation can be both enabled and implemented at the HTTP conduit level.
Note that if you have a JAX-RS KerberosAuthenticationFilter protecting the endpoints, then the filter will have an org.ietf.jgss.GSSContext
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instance
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available
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in
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the
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current
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CXF
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SecurityContext,
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via
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its
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KerberosAuthenticationFilter$KerberosSecurityContext
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implementation,
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which
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can
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be
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used
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to
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get
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to
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org.ietf.jgss.GSSCredential
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if
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the
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credential
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delegation
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is
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supported
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for
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a
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given
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source
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principal.
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The
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current
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credential
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if
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any
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can
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be
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set
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as
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a
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client
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property
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next,
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for
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example:
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{code:java} import org.ietf.jgss.GSSCredential; import org.apache.cxf.jaxrs.security.KerberosAuthenticationFilter; import org.apache.cxf.jaxrs.security.KerberosAuthenticationFilter.KerberosSecurityContext; import org.apache.cxf.phase.PhaseInterceptorChain; import org.apache.cxf.security.SecurityContext; @Path("service") public class MyResource { @Context private javax.ws.rs.core.SecurityContext securityContext; @GET public Book getBookFromKerberosProtectedStore() { WebClient wc = webClient.create("http://internal.com/store"); SecurityContext securityContext = PhaseInterceptorChain.getCurrentMessage().get(SecurityContext.class); if (securityContext instanceof KerberosSecurityContext) { KerberosSecurityContext ksc = (KerberosSecurityContext)securityContext; GSSCredential cred = ksc.getGSSContext().getDelegCred(); if (cred != null) { WebClient.getConfig(wc).getRequestContext().put(GSSCredential.class.getName(), cred); } } return wc.get(Book.class); } } {code} |
The
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HTTPConduit
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or
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KerberosAuthOutInterceptor
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handler
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will
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use
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the
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available
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GSSCredential.
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Also
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note
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that
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KerberosAuthOutInterceptor
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can
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have
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its
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"credDelegation"
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property
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set
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to
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"true"
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if
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it
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is
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used
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instead
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of
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HTTPConduit
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on
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the
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client
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side,
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when
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enabling
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the
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delegation
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initially.
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