Securing Stash with Tomcat using SSL

1. Generate a self-signed certificate

Self-signed certificates are useful where you require encryption but do not need to verify the website identity. They are commonly used for testing and on internal corporate networks (intranets).

Users may receive a warning that the site is untrusted and have to "accept" the certificate before they can access the site. This usually will only occur the first time they access the site.

The following approach to creating a certificate uses Java's keytool, for Java 1.6. Other tools for generating certificates are available.

To generate a self-signed certificate:

• Log in with the user account that Stash will run under, and run the following command:

  Windows	"%JAVA_HOME%\bin\keytool" -genkey -alias tomcat -keyalg RSA
  Linux, MacOS and Unix	$JAVA_HOME/bin/keytool -genkey -alias tomcat -keyalg RSA

  
  This will create (if it doesn't already exist) a new .keystore file located in the home directory of the user you used to run the keytool command.

Note the following:

• When running the keytool command you will be prompted with: What is your first and last name?
  
  You must enter the fully qualified hostname of the server running Stash. This is the name you would type in your web browser after 'http://' (no port number) to access your Stash installation. The qualified host name should match the base URL you have set in Stash (without the port number).

• The keytool utility will also prompt you for two passwords: the keystore password and the key password for Tomcat.
  
  You must use the same value for both passwords, and the value must be either:

1. • "changeit", which is the default value Tomcat expects, or
   • any other value, but you must also specify it in conf/server.xml by adding the following attribute to the <Connector/> tag: keystorePass="<password value>"

2. Configure HTTPS in Tomcat

To configure HTTPS in Tomcat:

• Edit conf/server.xml and, at the bottom, before the </Service> tag, add this section (or uncomment it if it already exists):

  <Connector port="8443" 
    maxHttpHeaderSize="8192" 
    SSLEnabled="true"
  	maxThreads="150" 
    minSpareThreads="25" 
    maxSpareThreads="75"
  	enableLookups="false" 
    disableUploadTimeout="true" 
    useBodyEncodingForURI="true"
  	acceptCount="100" 
    scheme="https" 
    secure="true"
  	clientAuth="false" 
    sslProtocol="TLS" />
  

  
  This enables SSL access on port 8443 (the default for HTTPS is 443, but 8443 is used instead of 443 to avoid conflicts).

Exporting the self-signed certificate

If Stash will run as the user who ran the keytool --genkey command, you do not need to export the certificate.

You may need to export the self-signed certificate, so that you can import it into a different keystore, if Stash will not be run as the user executing keytool --genkey. You can do so with the following command:

"%JAVA_HOME%\bin\keytool" -export -alias tomcat -file file.cer

$JAVA_HOME/bin/keytool -export -alias tomcat -file file.cer

If you generate the certificate as one user and run Stash as another, you'll need to do the certificate export as the generating user and the import as the target user.

Requesting a CA certificate

Digital certificates that are issued by trusted 3rd party CAs (Certification Authorities) provide verification that your website does indeed represent your company.

When running Stash in a production environment, you will need a certificate issued by a CA, such as VeriSign, Thawte or TrustCenter. The instructions below are adapted from the Tomcat documentation.

First, you will generate a local certificate and create a 'certificate signing request' (CSR) based on that certificate. You then submit the CSR to your chosen certificate authority. The CA will use that CSR to generate a certificate for you.

1. Use Java's keytool utility to generate a local certificate, as described in the section above.

2. Use the keytool utility to generate a CSR, replacing the text <MY_KEYSTORE_FILENAME> with the path to and file name of the .keystore file generated for your local certificate:

   Windows	"%JAVA_HOME%\bin\keytool" -certreq -keyalg RSA -alias tomcat -file certreq.csr -keystore <MY_KEYSTORE_FILENAME>
   Linux, MacOS and Unix	$JAVA_HOME/bin/keytool -certreq -keyalg RSA -alias tomcat -file certreq.csr -keystore <MY_KEYSTORE_FILENAME>

3. Submit the generated file called certreq.csr to your chosen certificate authority. Refer to the documentation on the CA's website to find out how to do this.
4. The CA will send you a certificate.

5. Import the new certificate into your local keystore. Assuming your certificate is called "file.cer" whether obtained from a CA or self-generated, the following command will add the certificate to the keystore:

   Windows	"%JAVA_HOME%\bin\keytool" -import -alias tomcat -file file.cer
   Linux, MacOS and Unix	$JAVA_HOME/bin/keytool -import -alias tomcat -file file.cer

Troubleshooting

Here are some troubleshooting tips if you are using a self-signed key created by keytool, or a CA certificate, as described above.

When you enter "https://localhost:8443/" in your browser, if you get a message such as "Cannot establish a connection to the server at localhost:8443", look for error messages in your logs/catalina.out log file. Here are some possible errors with explanations:

SSL + Apache + IE problems

Some people have reported errors when uploading attachments over SSL using IE. This is due to an IE bug, and can be fixed in Apache by setting:

BrowserMatch ".MSIE." \
	nokeepalive ssl-unclean-shutdown \
	downgrade-1.0 force-response-1.0

Google has plenty more on this.

Can't find the keystore

java.io.FileNotFoundException: /home/user/.keystore (No such file or directory)

This indicates that Tomcat cannot find the keystore. The keytool utility creates the keystore as a file called .keystore in the current user's home directory. For Unix/Linux the home directory is likely to be /home/<username>. For Windows it is likely to be C:\User\<UserName>.

Make sure you are running Stash as the same user who created the keystore. If this is not the case, or if you are running Stash on Windows as a service, you will need to specify where the keystore file is in conf/server.xml. Add the following attribute to the connector tag you uncommented:

 keystoreFile="<location of keystore file>"

Incorrect password

java.io.IOException: Keystore was tampered with, or password was incorrect

You used a different password than "changeit". You must either use "changeit" for both the keystore password and for the key password for Tomcat, or if you want to use a different password, you must specify it using the keystorePass attribute of the Connector tag, as described above.

Passwords don't match

java.io.IOException: Cannot recover key

You specified a different value for the keystore password and the key password for Tomcat. Both passwords must be the same.

Wrong certificate

javax.net.ssl.SSLException: No available certificate corresponds to the SSL cipher suites which are enabled.

If the Keystore has more than one certificate, Tomcat will use the first returned unless otherwise specified in the SSL Connector in conf/server.xml.

Add the keyAlias attribute to the Connector tag you uncommented, with the relevant alias, for example:

<Connector port="8443" 
  maxHttpHeaderSize="8192"
	maxThreads="150" 
  minSpareThreads="25" 
  maxSpareThreads="75"
	enableLookups="false" 
  disableUploadTimeout="true" 
  useBodyEncodingForURI="true"
	acceptCount="100" 
  scheme="https" 
  secure="true"
	clientAuth="false" 
  sslProtocol="TLS"
	keystoreFile="/opt/local/.keystore"
	keystorePass="removed"
	keyAlias="tomcat"/> 

Using Apache Portable Runtime

APR uses a different SSL engine, and you will see an exception like this in your logs

SEVERE: Failed to initialize connector [Connector[HTTP/1.1-8443]]
LifecycleException:  Protocol handler initialization failed: java.lang.Exception: No Certificate file specified or invalid file format

The reason for this is that the APR Connector uses OpenSSL and cannot use the keystore in the same way. You can rectify this in one of two ways:

Use the Http11Protocol to handle SSL connections

Edit the server.xml so that the SSL Connector tag you just uncommented specifies the Http11Protocol instead of the APR protocol:

 <Connector port="8443" 
  protocol="org.apache.coyote.http11.Http11Protocol"
	maxHttpHeaderSize="8192" 
  SSLEnabled="true" 
  keystoreFile="${user.home}/.keystore"
	maxThreads="150" 
  enableLookups="false" 
  disableUploadTimeout="true"
	acceptCount="100" 
  scheme="https" 
  secure="true"
	clientAuth="false" 
  sslProtocol="TLS" 
  useBodyEncodingForURI="true" />

Configure the Connector to use the APR protocol

This is only possible if you have PEM encoded certificates and private keys. If you have used OpenSSL to generate your key, then you will have these PEM encoded files - in all other cases contact your certificate provider for assistance.

 <Connector port="8443" 
  maxThreads="200"
	scheme="https" 
  secure="true" 
  SSLEnabled="true"
	SSLCertificateFile="${user.home}/certificate.pem"
	SSLCertificateKeyFile="${user.home}/key.pem"
	clientAuth="optional"  
  SSLProtocol="TLSv1"/>

Enabling client authentication

To enable client authentication in Tomcat, ensure that the value of the clientAuth attribute in your Connector element of your Tomcat's server.xml file is true.

<Connector
	...
	clientAuth="true"
	... /> 

For more information about Connector element parameters, please refer to the 'SSL Support' section of the Tomcat 6.0 documentation.

Wrong certificate type

If the certificate from the CA is in PKSC12 format, add the keystoreType attribute to the SSL Connector in conf/server.xml.

keystoreFile="/opt/local/wildcard_atlassian_com.p12"
keystorePass="removed"
keystoreType="PKCS12"/>

Certificate chain is incomplete

If the root certificate and intermediary certificate(s) aren't imported into the keystore before the entity/domain certificate, you will see the following error:

[root@dev atlas]# /usr/java/jdk1.7.0_17/bin/keytool -import -alias tomcat -file my_entity_cert.crt
Enter keystore password:
keytool error: java.lang.Exception: Failed to establish chain from reply

Most likely, the CA sent a compressed file containing several certificates. The import order matters so you must import the root certificate first, followed by one or many intermediate certificates, followed lastly by the entity/domain certificate. There are many resources online that provide guidance for certificate installation for Tomcat (Java-based) web servers using keytool.