SSL on Tomcat in a nutshell

Setting up SSL on Tomcat is easy and you don’t have to do much for converting your web application to work with the Https protocol. But however, the problem you would find to set up SSL is the documentation available over the web. The documentation source is available on the Apache site but it starts off good and ends with a lot of confusion. Especially I was confused on the OpenSSL part where it says to use OpenSSL.

It might be good in a production environment to use OpenSSL but if you just want to test out SSL with Tomcat alone then it is more than enough to just have your JDK and Tomcat setups. So I would make you walk through the same steps which I did while getting SSL up and running and building a secured web app within a matter of minutes.

The things which I have used to setup SSL consists of:

  • JDK 1.6
  • Tomcat 6

Even though I have used the latest version I don’t see any problems which you might face in carrying out the same set of steps for JDK 1.5 which I am about to explain. JDK comes shipped with a keytool executable which is required to generate a keystore. The keytool can be found in the earlier version of JDK too. The 3 steps which would make you to get started with setting up SSL are:

  1. Generating the Keystore file
  2. Configuring Tomcat for using the Keystore file
  3. Configuring your web application to work with SSL

Let’s get this party started now.

1. Generating the KeyStore file

The keystore file is the one which would store the details of the certificates necessary to make the protocol secured. Certificates contain the information as to who is the source from which you are receiving the application data and to authenticate whether it is the intended party or not. To make this keystore you would have to use the keytool. So open command prompt in Windows or the shell in Linux and type:

cd %JAVA_HOME%/bin on Windows

cd $JAVA_HOME/bin on Linux

You would land up in the Java bin directory. Now time to run the keytool command. You have to provide some parameters to the command as follows :

keytool -genkey -alias shastri -keypass ttadmin -keystore shastri.bin -storepass ttadmin

The highlighted words are the ones which you would have to change according to your requirements. But keep one thing in mind that both thekeypass and storepass passwords should be the same. The .bin file is actually your keystore file. It would now start a questionnaire. So fill in the relevant details accordingly. Look below for a reference as to what to answer for the questions.

What is your first and last name?
[Unknown]: Tom Cat
What is the name of your organizational unit?
[Unknown]: GCET
What is the name of your organization?
[Unknown]: munarch
What is the name of your City or Locality?
[Unknown]: grnoida
What is the name of your State or Province?
[Unknown]: up
What is the two-letter country code for this unit?
[Unknown]: IN
Is CN=Tom Cat, OU=GCET, O=munarch, L=grnoida, ST=up, C=IN correct?
[no]: yes

The command would then conclude. It would make a .bin file with the name you had provided inside the bin directory itself. In my case it was shastri.bin which was located in

C:\Program Files\Java\jdk1.6.0_02\bin\

Put the .bin file in the webapps directory of Tomcat. This is required to avoid the need to give an absolute path of the file in the next step.

2. Configuring Tomcat for using the Keystore file

Here we would be making some changes to the server.xml file inside tomcat to tell it to use the keystore which was created in the earlier step for configuring SSL. Open the file server.xml which can be found as:

<CATALINA_HOME>/conf/server.xml

Now you have to modify it. Find the Connector element which has port=”8443″ and uncomment it if already not done. Add two lines. The highlighted lines are the newly added ones.

<Connector port=”8443″
maxThreads=”150″ minSpareThreads=”25″ maxSpareThreads=”75″
enableLookups=”true” disableUploadTimeout=”true”
acceptCount=”100″ debug=”0″ scheme=”https” secure=”true”
clientAuth=”false” sslProtocol=”TLS”
keystoreFile=”../webapps/shastri.bin”
keystorePass=”ttadmin” />

You can notice that I have given the path to the keystore File property as relative to tomcat bin directory because the startup command will look for the .bin file. Now all you have to do is start your server and check the working of SSL by pointing your browser to the URL to:

https://localhost:8443/

Now that you have your tomcat running in the SSL mode you are ready to deploy an application to test its working. You must note that still your tomcat can run in normal mode too at the same time i.e on port 8080 with http. So it is but obvious that any application deployed to the server will be running on http and https at the same time. This is something that we don’t want. We want our application to run only in the secured mode.

3. Configuring your web application to work with SSL

In order to do this for our test, take any application which has already been deployed successfully in Tomcat and first access it through http and https to see if it works fine. If yes, then open the web.xml of that application and just add this XML fragment before web-app ends i.e </web-app>

<security-constraint>
<web-resource-collection>
<web-resource-name>securedapp</web-resource-name>
<url-pattern>/*</url-pattern>
</web-resource-collection>
<user-data-constraint>
<transport-guarantee>CONFIDENTIAL</transport-guarantee>
</user-data-constraint>
</security-constraint>

Explanation of the fragment is beyond the scope of this tutorial but all you should notice is that the /* indicates that now, any resource in your application can be accessed only with https be it Servlets or JSP’s. The term CONFIDENTIAL is the term which tells the server to make the application work on SSL. If you want to turn the SSL mode for this application off then just turn don’t delete the fragment. Just put the value as NONE instead of CONFIDENTIAL.

And that’s how its Done.

Happy Coding 🙂

 

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