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Recipe 15.3 Using BASIC Authentication
Use the security-constraint, login-config, and security-role elements in the deployment descriptor to protect one or more URLs.
BASIC authentication is a security method that has been used with web resources for several years, and all popular browsers support it. This method of authentication involves the transfer of usernames and passwords over a network encoded with the Base64 content-encoding mechanism. Base64 is easy to decode and therefore not very secure. The solution is to combine BASIC authentication with SSL, which will further encrypt the data as it is transferred across the network (see Recipe 15.2).
Here is how setting up BASIC authentication works with web applications that you have installed on Tomcat:
You are probably familiar with what happens next: the browser displays a standard dialog window requesting the client to provide a username and password (Figure 15-1). If the username and password are incorrect, the browser will either give the user another chance to log in by redisplaying the dialog window, or simply send back a server status code "401: Unauthorized" type of response.
Example 15-4 shows the web.xml elements that are designed to initiate BASIC authentication for the URL pattern /sqlJsp.jsp.
<!-- Beginning of web.xml deployment descriptor --> <security-constraint> <web-resource-collection> <web-resource-name>JSP database component</web-resource-name> <url-pattern>/sqlJsp.jsp</url-pattern> <http-method>GET</http-method> <http-method>POST</http-method> </web-resource-collection> <auth-constraint> <role-name>dbadmin</role-name> </auth-constraint> <user-data-constraint> <transport-guarantee>CONFIDENTIAL</transport-guarantee> </user-data-constraint> </security-constraint> <login-config> <auth-method>BASIC</auth-method> </login-config> <security-role> <role-name>dbadmin</role-name> </security-role> <!-- Rest of web.xml deployment descriptor -->
The security-constraint element in Example 15-4 contains a web-resource-collection element. This element specifies the following constraints that apply to any requests for /sqlJsp.jsp:
Figure 15-1 shows the dialog box that Netscape 7.1 produces when Tomcat is using BASIC authentication. The URL is used is https://localhost:8443/home/sqlJsp.jsp.
Notice that the URL uses a secure connection to request the JSP: an HTTPS protocol and port 8443 on Tomcat.
Figure 15-2 shows a browser window after a client has failed authentication.
The Tomcat documentation and Recipe 15.2 on setting up SSL for use with authentication: http://jakarta.apache.org/tomcat/tomcat-4.1-doc/ssl-howto.html; Recipe 3.9 on restricting requests for certain servlets; Recipe 15.5 on logging out a user; Recipe 15.6-Recipe 15.9 on using JAAS.
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