WebSphere® Application Server supports plugging in a custom Java™ Authentication and
Authorization Service (JAAS) login module before or after the WebSphere Application Server
system login module. However, WebSphere Application Server does not support the replacement of the WebSphere
Application Server system login modules, which are used to create the WSCredential credential and
WSPrincipal principal in the Subject. By using a custom login module, you can either make additional
authentication decisions or add information to the Subject to make additional, potentially
finer-grained, authorization decisions inside a Java Platform, Enterprise Edition
(Java EE)
application.
About this task
WebSphere
Application Server enables you to propagate information downstream that is added to the Subject by a
custom login module. For more information, see Security attribute propagation. To
determine which login configuration to use for plugging in your custom login modules, see the
descriptions of the login configurations that are located in the System login configuration entry settings for Java Authentication and Authorization Service.
WebSphere
Application Server supports the modification of the system login configuration through the
administrative console and by using the wsadmin scripting utility. To configure the system login
configuration using the administrative console, click Security > Global
security. Under Java Authentication and Authorization Service, click System
logins.
Procedure
- Configure a system login configuration.
Refer to the following code sample to configure a system login configuration using the wsadmin
tool. The following sample Jacl script adds a custom login module into the Lightweight Third-party
Authentication (LTPA) web system login configuration.
Attention: Lines 32, 33, and 34 in the following code samples are split into two
lines.
1. #########################################
2. #
3. # Open security.xml
4. #
5. #########################################
6.
7.
8. set sec [$AdminConfig getid /Cell:hillside/Security:/]
9.
10.
11. #########################################
12. #
13. # Locate systemLoginConfig
14. #
15. #########################################
16.
17.
18. set slc [$AdminConfig showAttribute $sec systemLoginConfig]
19.
20. set entries [lindex [$AdminConfig showAttribute $slc entries] 0]
21.
22.
23. #########################################
24. #
25. # Append a new LoginModule to LTPA_WEB
26. #
27. #########################################
28.
29. foreach entry $entries {
30. set alias [$AdminConfig showAttribute $entry alias]
31. if {$alias == "LTPA_WEB"} {
32. set newJAASLoginModuleId [$AdminConfig create JAASLoginModule
$entry {{moduleClassName
"com.ibm.ws.security.common.auth.module.proxy.WSLoginModuleProxy"}}]
33. set newPropertyId [$AdminConfig create Property $newJAASLoginModuleId
{{name delegate}{value "com.ABC.security.auth.CustomLoginModule"}}]
34. $AdminConfig modify $newJAASLoginModuleId
{{authenticationStrategy REQUIRED}}
35. break
36. }
37. }
38.
39.
40. #########################################
41. #
42. # save the change
43. #
44. #########################################
45.
46. $AdminConfig save 47.
Attention: The wsadmin scripting utility inserts a new object to the end of the list. To
insert the custom login module before the AuthenLoginModule login module, delete the
AuthenLoginModule login module and recreate it after inserting the custom login module. Save the
sample script into a
sample.jacl file, and run the sample script by using the
following command:
wsadmin -f sample.jacl
- Remove the current LTPA_WEB login configuration and all of the login modules.
You can use the following sample Jacl script to remove the current LTPA_WEB login configuration
and all the login
modules:
48. #########################################
49. #
50. # Open security.xml
51. #
52. #########################################
53.
54.
55. set sec [$AdminConfig getid /Cell:hillside/Security:/]
56.
57.
58. #########################################
59. #
60. # Locate systemLoginConfig
61. #
62. #########################################
63.
64.
65. set slc [$AdminConfig showAttribute $sec systemLoginConfig]
66.
67. set entries [lindex [$AdminConfig showAttribute $slc entries] 0]
68.
69.
70. #########################################
71. #
72. # Remove the LTPA_WEB login configuration
73. #
74. #########################################
75.
76. foreach entry $entries {
77. set alias [$AdminConfig showAttribute $entry alias]
78. if {$alias == "LTPA_WEB"} {
79. $AdminConfig remove $entry
80. break 81. }
82. }
83.
84.
85. #########################################
86. #
87. # save the change
88. #
89. #########################################
90.
91. $AdminConfig save
- Recover the original LTPA_WEB configuration.
You can use the following sample Jacl script to recover the original LTPA_WEB configuration:
Attention: Lines 122, 124, and 126 in the following code samples are split into two or more
lines for illustrative purposes
only.
92. #########################################
93. #
94. # Open security.xml
95. #
96. #########################################
97.
98.
99. set sec [$AdminConfig getid /Cell:hillside/Security:/]
100.
101.
102. #########################################
103. #
104. # Locate systemLoginConfig
105. #
106. #########################################
107.
108.
109. set slc [$AdminConfig showAttribute $sec systemLoginConfig]
110.
111. set entries [lindex [$AdminConfig showAttribute $slc entries] 0]
112.
113.
114.
115. #########################################
116. #
117. # Recreate the LTPA_WEB login configuration
118. #
119. #########################################
120.
121.
122. set newJAASConfigurationEntryId [$AdminConfig create
JAASConfigurationEntry $slc {{alias LTPA_WEB}}]
123.
124. set newJAASLoginModuleId [$AdminConfig create
JAASLoginModule $newJAASConfigurationEntryId
{{moduleClassName
"com.ibm.ws.security.common.auth.module.proxy.WSLoginModuleProxy"}}]
125.
126. set newPropertyId [$AdminConfig create Property
$newJAASLoginModuleId {{name delegate}{value "com.ibm.ws.security.web.AuthenLoginModule"}}]
127.
128. $AdminConfig modify $newJAASLoginModuleId
{{authenticationStrategy REQUIRED}}
129.
130.
131. #########################################
132. #
133. # save the change
134. #
135. #########################################
136.
137. $AdminConfig save
- Have the ltpaLoginModule initialize the callback array in the login method.
The WebSphere
Application Server Version ltpaLoginModule and AuthenLoginModule login modules use the shared state
to save state information so that custom login modules can modify the information. The
ltpaLoginModule login module initializes the callback array in the login method by using the
following code. The callback array is created by the ltpaLoginModule login module only if an array
is not defined in the shared state area. In the following code sample, the error handling code is
removed to make the sample concise. If you insert a custom login module before the ltpaLoginModule
login module, the custom login module might follow the same style to save the callback into the
shared state.
Attention: In the following code sample, several lines of code are split into two lines
for illustrative purposes only.
138. Callback callbacks[] = null;
139. if (!sharedState.containsKey(
com.ibm.wsspi.security.auth.callback.Constants. CALLBACK_KEY)) {
140. callbacks = new Callback[3];
141. callbacks[0] = new NameCallback("Username: ");
142. callbacks[1] = new PasswordCallback("Password: ", false);
143. callbacks[2] = new com.ibm.websphere.security.auth.callback.
WSCredTokenCallbackImpl( "Credential Token: ");
144. try {
145. callbackHandler.handle(callbacks);
146. } catch (java.io.IOException e) {
147. . . .
148. } catch (UnsupportedCallbackException uce) {
149. . . .
150. }
151. sharedState.put( com.ibm.wsspi.security.auth.callback.
Constants.CALLBACK_KEY, callbacks);
152. } else {
153. callbacks = (Callback []) sharedState.get
( com.ibm.wsspi.security.auth.callback.Constants.CALLBACK_KEY);
154. }
- Have the AuthenLoginModule initialize the callback array.
The ltpaLoginModule and AuthenLoginModule login modules generate both a WSPrincipal object and a
WSCredential object to represent the authenticated user identity and security credentials. The
WSPrincipal and WSCredential objects also are saved in the shared state. A JAAS login uses a
two-phase commit protocol.
First, the login methods in login modules, which are configured in the login configuration, are
called. Then, their commit methods are called. A custom login module, which is inserted after the
ltpaLoginModule and the AuthenLoginModule login modules, can modify the WSPrincipal and WSCredential
objects before these objects are committed. The WSCredential and WSPrincipal objects must exist in
the Subject after the login is completed. Without these objects in the Subject, WebSphere Application Server
runtime code rejects the Subject to make security decisions.
AuthenLoginModule uses the following code to initialize the callback array:
Attention: In the following code sample, several lines of code are split into two lines
for illustrative purposes only.
155. Callback callbacks[] = null;
156. if (!sharedState.containsKey( com.ibm.wsspi.security.auth.
callback.Constants.CALLBACK_KEY)) {
157. callbacks = new Callback[6];
158. callbacks[0] = new NameCallback("Username: ");
159. callbacks[1] = new PasswordCallback("Password: ", false);
160. callbacks[2] = new com.ibm.websphere.security.auth.callback.
WSCredTokenCallbackImpl( "Credential Token: ");
161. callbacks[3] = new com.ibm.wsspi.security.auth.callback.
WSServletRequestCallback( "HttpServletRequest: ");
162. callbacks[4] = new com.ibm.wsspi.security.auth.callback.
WSServletResponseCallback( "HttpServletResponse: ");
163. callbacks[5] = new com.ibm.wsspi.security.auth.callback.
WSAppContextCallback( "ApplicationContextCallback: ");
164. try {
165. callbackHandler.handle(callbacks);
166. } catch (java.io.IOException e) {
167. . . .
168. } catch (UnsupportedCallbackException uce {
169. . . .
170. }
171. sharedState.put( com.ibm.wsspi.security.auth.callback.
Constants.CALLBACK_KEY, callbacks);
172. } else {
173. callbacks = (Callback []) sharedState.get(com.ibm.wsspi.security.
auth.callback.Constants.CALLBACK_KEY);
174. }
- Obtain the application context.
Three more objects, which contain callback
information for the login, are passed from the web container to the AuthenLoginModule login module:
a java.util.Map, an HttpServletRequest, and an HttpServletResponse object. These objects represent
the web application context.
You can obtain the application context, java.util.Map object, by calling the getContext method on
the WSAppContextCallback object. The java.util.Map object is created with the following deployment
descriptor information.
Attention: In the following code sample, several lines of code are split into two lines
for illustrative purposes only.
175. HashMap appContext = new HashMap(2);
176. appContext.put( com.ibm.wsspi.security.auth.callback.
Constants.WEB_APP_NAME,web_application_name);
177. appContext.put( com.ibm.wsspi.security.auth.callback.Constants.
REDIRECT_URL,errorPage);
What to do next
The application name and the HttpServletRequest object might be read by the custom login module
to perform mapping functions. The error page of the form-based login might be modified by a custom
login module. In addition to the JAAS framework, WebSphere Application Server supports the trust association
interface (TAI).
Other credential types and information can be added to the caller Subject during the
authentication process by using a custom login module. The third-party credentials in the caller
Subject are managed by WebSphere Application Server as part of the security context. The caller
Subject is bound to the running thread during the request processing. When a web or an Enterprise
JavaBeans (EJB) module is configured to use the caller identity, the user identity is
propagated to the downstream service in an EJB request. The WSCredential credential and any
third-party credentials in the caller Subject are not propagated downstream. Instead, some of the
information can be regenerated at the target server that is based on the propagated identity. Add
third-party credentials to the caller Subject at the authentication stage. The caller Subject, which
is returned from the WSSubject.getCallerSubject method, is read-only and cannot be modified. For
more information on the WSSubject subject, see Getting the caller subject from the thread for JAAS.