gigadot gigadot - 2 months ago 12
Java Question

Handle unauthorized error message for Basic Authentication in Spring Security

I am trying to use Spring Security 3.0.5 in my web application. Basically, I want to have a web service which return data in json format via

HTTP GET
.

I have implemented a RESTful service which returns data when the url
http://localhost:8080/webapp/json
is requested. This works fine with the following curl command

> curl http://localhost:8080/webapp/json
{"key":"values"}


After I added basic authentication using spring security, I can use following commands to get the data

> curl http://localhost:8080/webapp/json
<html><head><title>Apache Tomcat/6.0.29 - Error report .....
> curl -u username:password http://localhost:8080/webapp/json
{"key":"values"}


The former command returns standard tomcat error page since now it requires username and password. My question is whether it is possible to handle access denied in such a way that it prints out my own error message? i.e.

> curl http://localhost:8080/webapp/json
{"error":"401", "message":"Username and password required"}


Here is my spring security configuration and
AccessDeniedHandler
. As you can see, I am trying to add
access-denied-handler
which simply prints out a string through servlet response but it still does not print my own message on command line.

<?xml version="1.0" encoding="UTF-8"?>
<beans:beans xmlns="http://www.springframework.org/schema/security"
xmlns:beans="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
http://www.springframework.org/schema/security http://www.springframework.org/schema/security/spring-security-3.0.xsd">
<global-method-security secured-annotations="enabled"/>

<beans:bean name="access-denied" class="webapp.error.JSONAccessDeniedHandler"></beans:bean>

<http auto-config="true">
<access-denied-handler ref="access-denied"/>
<intercept-url pattern="/json" access="ROLE_USER,ROLE_ADMIN" />
<http-basic />
</http>

<authentication-manager>
<authentication-provider>
<password-encoder hash="md5"/>
<user-service>
...
</user-service>
</authentication-provider>
</authentication-manager>

</beans:beans>


AccessDeniedHandler.java


package webapp.error;

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.security.access.AccessDeniedException;
import org.springframework.security.web.access.AccessDeniedHandler;

public class JSONAccessDeniedHandler implements AccessDeniedHandler {

@Override
public void handle(HttpServletRequest request, HttpServletResponse response, AccessDeniedException accessDeniedException) throws IOException, ServletException {
PrintWriter writer = response.getWriter();
writer.print("{\"error\":\"401\", \"message\":\"Username and password required\"}");
}

}

Answer

I have solved my problem so I think I should share it here. This configuration allows server to send out error message differently depending on the requesting software. If the request comes from a web browser, it will check the User-Agent header and redirect to a form login if necessary. If the request comes from, for example, curl, it will print out plain text error message when the authentication fails.

<?xml version="1.0" encoding="UTF-8"?>
<beans
    xmlns="http://www.springframework.org/schema/beans"
    xmlns:sec="http://www.springframework.org/schema/security"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:p="http://www.springframework.org/schema/p"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
        http://www.springframework.org/schema/context  http://www.springframework.org/schema/context/spring-context-3.0.xsd
        http://www.springframework.org/schema/security http://www.springframework.org/schema/security/spring-security-3.0.xsd">

    <!-- AspectJ pointcut expression that locates our "post" method and applies security that way
    <protect-pointcut expression="execution(* bigbank.*Service.post*(..))" access="ROLE_TELLER"/>-->
    <sec:global-method-security secured-annotations="enabled"/>

    <bean id="basicAuthenticationFilter"
          class="org.springframework.security.web.authentication.www.BasicAuthenticationFilter"
          p:authenticationManager-ref="authenticationManager"
          p:authenticationEntryPoint-ref="basicAuthenticationEntryPoint" />

    <bean id="basicAuthenticationEntryPoint"
          class="webapp.PlainTextBasicAuthenticationEntryPoint"
          p:realmName="myWebapp"/>

    <bean id="formAuthenticationEntryPoint"
          class="org.springframework.security.web.authentication.LoginUrlAuthenticationEntryPoint"
          p:loginFormUrl="/login.jsp"/>

    <bean id="daep" class="org.springframework.security.web.authentication.DelegatingAuthenticationEntryPoint">
        <constructor-arg>
            <map>
                <entry key="hasHeader('User-Agent','Mozilla') or hasHeader('User-Agent','Opera') or hasHeader('User-Agent','Explorer')" value-ref="formAuthenticationEntryPoint" />
            </map>
        </constructor-arg>
        <property name="defaultEntryPoint" ref="basicAuthenticationEntryPoint"/>
    </bean>

    <sec:http entry-point-ref="daep">
        <sec:intercept-url pattern="/login.jsp*" filters="none"/>
        <sec:intercept-url pattern="/json" access="ROLE_USER,ROLE_ADMIN"  />
        <sec:intercept-url pattern="/json/*" access="ROLE_USER,ROLE_ADMIN"  />
        <sec:logout
            logout-url="/logout"
            logout-success-url="/home.jsp"/>
        <sec:form-login
            login-page="/login.jsp"
            login-processing-url="/login"
            authentication-failure-url="/login.jsp?login_error=1" default-target-url="/home.jsp"/>
        <sec:custom-filter position="BASIC_AUTH_FILTER" ref="basicAuthenticationFilter" />
    </sec:http>

    <sec:authentication-manager alias="authenticationManager">
        <sec:authentication-provider>
        ...
        </sec:authentication-provider>
    </sec:authentication-manager>

</beans>

PlainTextBasicAuthenticationEntryPoint by extending org.springframework.security.web.authentication.www.BasicAuthenticationEntryPoint

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.security.core.AuthenticationException;
import org.springframework.security.web.authentication.www.BasicAuthenticationEntryPoint;

public class PlainTextBasicAuthenticationEntryPoint extends BasicAuthenticationEntryPoint {

    @Override
    public void commence(HttpServletRequest request, HttpServletResponse response, AuthenticationException authException) throws IOException, ServletException {
        response.addHeader("WWW-Authenticate", "Basic realm=\"" + getRealmName() + "\"");
        response.setStatus(HttpServletResponse.SC_UNAUTHORIZED);
        PrintWriter writer = response.getWriter();
        writer.println("HTTP Status " + HttpServletResponse.SC_UNAUTHORIZED + " - " + authException.getMessage());
    }
}