Setting up Apache Tomcat and a Simple Apache SOAP Client for SSL Communication.
Introduction
This document gives steps involved in setting up Apache Tomcat and a simple
Apache SOAP client for SSL
communication.
The aim of this document is to allow a person with minimum Java security
to be able to set up SSL connection in a Apache SOAP/Tomcat Application.
The steps you will carry out are:
-
Install the Java Secure Socket Extensions (JSSE) package (available from
Sun).
-
Generate Client and Server Certificates for SSL communication.
-
Generate a Server Key and Certificate
-
Export the Server Certificate
-
Generate a Client Key and Certificate
-
Export the Client Certificate
-
Import the Certificates into the Keystores
-
Set up Tomcat for SSL Communication
-
Modify the SOAP Client to use SSL
Also included in this document is:
-
A short tutorial on creating X.509 Certificate Chains
-
A section on troubleshooting SOAP and SSL installations
Assumptions
It is assumed that you have installed Apache
SOAP and Apache Tomcat,
and that the sample SOAP applications are working.
Tools needed for Installation
Step 1: Install JSSE
-
Before you do anything, read the installation instructions for JSSE!
(they are available online at: http://java.sun.com/products/jsse/install.html).
-
Add the JSSE jars to your classpath. This should hopefully add it to the
classpath of your Tomcat server. If not, add it to the classpath of the
Tomcat server or just copy the JSSE jar files to the lib directory of Tomcat
(e.g. C:\jakarta-tomcat-3.2.1\lib). This will automatically load
on start-up of Tomcat.
The JSSE 1.0.2 jars that you need in your classpath are:
-
jsse.jar
-
jcert.jar
-
jnet.jar
Step 2: Generate Client and Server Certificates
It is necessary to generate a Certificate for the client and the server.
These Certificates are then imported into a keystore, to which the client
and server connect.
The keystore acts as a database for security certificates.
You are going to use the keytool utility in the JDK to do
these tasks (see Sun's
documentation for more information on this tool).
Step 2a: Generate a Server Key and Certificate
Launch keytool from a shell (or command prompt) to generate your
public and private key.
Note that the Certificate and keystore files will be generated in the
directory you run keytool from.
Use keytool as follows:
keytool -genkey -alias tomcat-sv -dname "CN=[Common Name],OU=[Organisation
Unit], O=[Organisation Name], L=[Locality], S=[State Name], C=[Two-Letter
Country Code]" -keyalg RSA -keypass [private key password] -storepass [keystore
password] -keystore [keystore file name]
For example, to generate a keystore (in file server.keystore)
for server soapsvr.test.tcd.ie using password changeit
(for both the keystore and the certificate) in the Computer Engineering
group at Trinity College Dublin, Ireland, one would type the following:
keytool -genkey -alias tomcat-sv -dname "CN=soapsvr.test.tcd.ie, OU=ComputerEngineering,
O=Trinity College Dublin, L=Dublin, S=Dublin, C=IE" -keyalg RSA -keypass
changeit -storepass changeit -keystore server.keystore
Note that
-
The RSA algorithm is used to generate certificates.
-
Ensure that the 'CN' field that you specify when you create the server
certificate matches the name of the machine on which you're running tomcat,
or your browser will complain about certificate name mis-matches (not a
problem on a test server, a big problem on a production server!).
Step 2b: Export the Server Certificate
>From command prompt run this command to export your certificate from the
keystore into an external file (we do this so we can import the certificate
into the client's keystore as a trusted certificate).
keytool -export -alias tomcat-sv -storepass changeit -file server.cer -keystore server.keystore
If everything works, you should now have a file called server.cer
which contains your server's certificate.
Step 2c: Generate a Client Key and Certificate
This step is very similar to the generation of the server key and certificate
- it uses the same keytool tool with different parameters.
Note that the keystore file name has changed (it is now client.keystore).
Use keytool as follows:
keytool -genkey -alias tomcat-cl -dname "CN=Client,OU=TRL, O=IBM,
L=Yamato-shi, S=Kanagawa-ken, C=JP" -keyalg RSA -keypass changeit -storepass
changeit -keystore client.keystore
Step 2d: Export the Client Certificate
This step is very similar to the export of the server certificate - it
uses the same keytool tool with different parameters:
keytool -export -alias tomcat-cl -storepass changeit -file client.cer -keystore client.keystore
If everything works, you should now have a file called client.cer
which contains your client's certificate.
Step 2e: Import the Certificates into the Keystores
We want the client certificate to be added to the server's keystore, and
the server's certificate to be added to the client's keystore.
Doing this will mean that the client and server trust one another.
Import the server certificate into the client's keystore:
keytool -import -v -trustcacerts -alias tomcat -file server.cer
-keystore client.keystore -keypass changeit -storepass changeit
Import the client certificate into the server's keystore: keytool
-import -v -trustcacerts -alias tomcat -file client.cer -keystore server.keystore
-keypass changeit -storepass changeit
Step 3: Set up Tomcat for SSL Communication
Step 3a: Modify your Tomcat Configuration File
You need to amend server.xml (located in the conf directory of
Apache Tomcat). Add the following lines to the xml file:
<Connector className ="org.apache.tomcat.service.PoolTcpConnector">
<Parameter name="handler" value ="org.apache.tomcat.service.http.HttpConnectionHandler"/>
<Parameter name="port" value="8443"/>
<Parameter name="socketFactory" value="org.apache.tomcat.net.SSLSocketFactory" />
<Parameter name="keystore" value="c:\apache\soap-2_3\bin\server.keystore" />
<Parameter name="keypass" value="changeit"/>
<Parameter name="clientAuth" value="true"/>
</Connector>
Note that the value used for the keystore parameter (shown in
bold above) may be different on your machine; it should contain the full
path and filename of the server keystore file (server.keystore)
generated in Step 2a above. Note also that the port number we chose to
use for SSL in the above configuration is 8443. The port normally used
for HTTPS is 443, but for testing we are using 8443.
Step 3a: Test your HTTPS server
At this point, you should restart your Tomcat server. It will probably
take a bit longer to start up. You can now use a web browser to test that
it is working.
Test the SSL installation by opening your browser and typing in the
following URL:
https://servername:8443/index.html
Note that servername should be replaced with the name of the server
on which you are running Tomcat. If SSL is working then you should see
the default home page for your Tomcat installation.
Your browser may generate a warning about un-trusted certificates or
unrecognised authorities (just click OK).
Step 4: Modify the SOAP Client to use SSL
Step 4a: Java SSL Client
You need to set up properties before you call the URL in the SOAP client.
Here is an example SOAP client that calls a SOAP service using HTTPS on
a Tomcat server:
// classes for ssl
import javax.net.ssl.SSLSocketFactory;
import java.security.Security;
...
//
// setup some ssl-specific stuff
//
// specify the location of where to find key material for the default TrustManager (this overrides jssecacerts and cacerts)
System.setProperty("javax.net.ssl.trustStore","C:\\jdk1.3\\bin\\client.keystore");
// use Sun's reference implementation of a URL handler for the "https" URL protocol type.
System.setProperty("java.protocol.handler.pkgs","com.sun.net.ssl.internal.www.protocol");
// dynamically register sun's ssl provider
Security.addProvider(new com.sun.net.ssl.internal.ssl.Provider());
// note that the url is using https protocol and not http
URL urls = new URL( "https://localhost:8443/soap/servlet/rpcrouter");
//
// prepare and then execute a SOAP method
//
// output some basic information
System.out.println("\nUsing " + urls.getProtocol() + " to connect to " + urls.getHost() + " on port #" + urls.getPort());
// prepare the service invocation as usual
Call call = new Call();
String urn = "urn:demo:checkflight";
call.setTargetObjectURI( urn );
call.setMethodName( "getFlightInfo" );
// set up any parameters as usual
...
// Invoke the call
Response resp;
try
{
resp = call.invoke(urls, "");
}
catch (SOAPException e)
{
System.err.println("Caught SOAPException (" + e.getFaultCode() + "): " + e.getMessage());
e.printStackTrace();
return;
}
Once again the bold directory path is a pointer to the client keystore.
This may have to be changed depending on where you generated it. Also note
that the url is https and not http. It's an easy mistake to make!
Step 4b: Java SSL Client with Proxy [Optional]
If your client needs to use a proxy server in order to access the SOAP
service, then add the following lines to your code:
System.setProperty("https.proxyHost", "proxy"); // set name of proxy server that supports ssl
System.setProperty("https.proxyPort", "8080"); // set port number for proxy server that supports ssl
Use the following for Proxy without SSL:
System.setProperty("proxySet", "true"); // enable proxying
System.setProperty("proxyHost", "proxy"); // set name of proxy server
System.setProperty("proxyPort", "8080"); // set port number for proxy server
If you are using Socks proxy then set these (system) properties:
System.setProperty("socksProxyHost", "hostname"); // set name of socks server
System.setProperty("socksProxyPort", "1080"); // set port number for socks server
Creating X.509 Certificate Chains
By Darrell Drake
Overview
This instruction set covers creating mutual trust between two entities
using a certificate chains (my certificate with an attached lineage of
public certificates), which is more practical in a production environment
than the minimal security approach. In this case a principal is trusted
if any of the certificates in its chain are trusted. Additional tool needed:
IBM KeyMan, which can read and issue certificates from keystores in the
JKS and PKCS12 formats. Other formats (e.g. IBM CMS Key Database) don't
work well, at least in my experience.
Downloading KeyMan
KeyMan can be downloaded from: http://www.alphaworks.ibm.com/tech/keyman.
Creating a new Keystore and Keypair using KeyMan
-
From the initial window, click on the "create new" icon on the left
OR
from an already-open KeyMan window, under the File menu choose New.
-
Specify the type of keystore (pkcs 7, 12 and JKS are options)
-
Immediately the template is created
-
Under the Actions menu choose generate key
-
Select the desired key algorithm and length, click OK
-
WAIT
Opening an existing keystore file
-
From the initial window, click on the "open" icon on the right
OR
from an already-open KeyMan window, under the File menu choose Open
-
Select "local resource", click next
-
Enter or browse for the filename, click next
-
If applicable, enter the password protecting the file
Generating a self-signed certificate using KeyMan (for new serverkeystore)
-
Make sure the new key pair (and just the key pair) is selected
-
Under the Actions menu, choose Create Certificate
-
Choose Self-Signed Certificate, click next
-
Fill in the principal information as requested, click next
-
Select the period of validity for the new certificate, click next
Requesting a client certificate using keytool
-- using keytool (after creating keyEntry "alias")
keytool -certreq {-alias alias} {-sigalg sigalg} {-file certreq_file}
[-keypass keypass] {-storetype storetype} {-keystore keystore} [-storepass
storepass] {-v} {-Jjavaoption}
If you leave the "-file certreq_file" part out, the pkcs10
request will be printed to your standard output, which you can highlight
and copy to the system clipboard, transfer to a file or directly into KeyMan
(see next step "issuing certificate"). The principal information in the
request will be what you entered when using the "-genkey" command earlier.
Requesting a client certificate using KeyMan (after creating a key pair)
-
Make sure the new key pair (and just the key pair) is selected
-
Under the Actions menu, choose Request Certificate
-
Choose "Generate a PKCS#10 Request", click next
OR
If you want to get a commercial certificate for your server, choose
"Go online to a CA" (I don't know the remaining steps for doing that)
-
Fill in the principal information as requested, click next
-
Enter the filename where you want to save the request,
OR
Choose to copy the request to the system clipboard, click next
-
The request is now stored in the location that you specified.
Issuing a client certificate using KeyMan
(aka acting as your own CA, signing a PKCS#10 certificate request)
-
Open the keystore that contains your server's private certificate
-
Under the Actions menu, choose Create Certificate
-
Choose Sign a PKCS#10 request, click next
-
Enter or browse for the filename containing the request,
OR
Choose to load the request from the system clipboard (if you stored
it there), click next
-
Review the principal info (recommended: verify it offline in production
scenario)
-
Select the period of validity for the new certificate, click next
-
Enter the [path-qualified] filename where you will store the new certificate,
click next
-
NOT RECOMMENDED: saving the certificate to the clipboard (created a single
cert entry on the client side instead of chain in my experience).
Importing your new certificate from the CA's Using Keytool
(after importing server's cert as trusted CA cert)
keytool -import {-alias alias} {-file cert_file} [-keypass keypass]
{-storetype storetype} {-keystore keystore} [-storepass storepass] {-v}
{-Jjavaoption}
It should simply say "certificate was added to keystore" and finish
with no dialog. ["alias" is your original keyEntry; the default self-signed
certificate should now be overwritten with the CA-signed certificate]
Importing your new certificate from the CA's Using KeyMan
-
Under the File menu, choose Import
-
Select "local resource", click next
-
Enter or browse for the filename ("cert_file"), click next
-
You should get a popup dialog saying "Private Certificate Received", click
OK
Saving the new or changed keystore file using KeyMan
-
Under the File menu choose Save
-
Enter the [path-qualified] filename (leave the default file format if PKCS12),
click ok
-
Enter the password if prompted
NOTE: If the server gets a certificate chain from a higher CA entity, the
client could import that higher entity's certificate as a trusted CA certificate
(it may already have that certificate by default), and it would thus trust
the server certificate.
Troubleshooting
One extremely useful tip for troubleshooting SSL is to use the built-in
SSL debugging features:
java -djavax.net.debug=help YourClassname
(this will give you a help message for SSL debugging features)
Unknown Protocol Error
Problem: Exception in thread "main" java.net.MalformedURLException:
unknown protocol: https
Solution: Ensure that the ssl-specific initialisation code happens
before you create a java.net.URL object.
Unrecognized SSL handshake
Problem: ContextManager: IOException reading request, ignored - javax.net.ssl.SSLException:
Unrecognized SSL handshake.
Solution: The most likely problem is either:
(a) your url is http:// instead of https://
or
(b) your client and server are using different versions of soap.jar
(possibly 2.0/2.1).
Bad Certificate Error
Redo Steps 2, 3 and 4.
Socket Write Error
Problem: java.lang.reflect.InvocationTargetException: java.net.SocketException:
Connection aborted by peer: socket write error
Solution: This problem occurs because (for some reason) the server
cannot authenticate the client. Change the following line in server.xml:
<Parameter name="clientAuth" value="false"/>
Keytool Error
Problem: keytool error: java.io.IOException: Keystore was tampered
with, or password was incorrect
Solution: Try deleting the keystore file and re-creating it (see the
instructions at the beginning of this page).
Further Information
SOAP
SSL