SSL (Secure Sockets Layer) is a commonly-used protocol for managing the security of message transmission on the Internet. SSL in your web server provides support for the familiar https:// protocol.

Resin is not always responsible for SSL

When you are using Resin as a servlet runner behind another web server, such as Apache or IIS, the web server is responsible for handling SSL. The request looks like a regular unencrypted request to Resin.

In a similar fashion, a hardware accelerator is sometimes used to boost the performance of a server supporting SSL. This causes the incoming requests to look like regular unencrypted requests to Resin.

Even if you're using Apache/IIS for SSL support, you can still use Resin's standalone web server for non-SSL pages. Your resin.conf will need to list both a <http port='80'/> and a <srun port='6802'/>.

What SSL provides

SSL provides two kinds of protection, encryption and server authentication.

Encryption

SSL provides encryption of the data traffic betweeen a client and a server. When the traffic is encrypted, an interception of that traffic will not reveal the contents because they have been encrypted - it will be unusable nonsense.

SSL uses public key cryptography. Public key cryptography is based upon a pair of keys, the public key and the private key. The public key is used to encrypt the data. Only the corresponding private key can successfully decrypt the data.

For example, when a browser connects to Resin, Resin provides the browser a public key. The browser uses the public key to encrypt the data, and Resin uses the private key to decrypt the data. For this reason, it is important that you never allow anyone access to the private key, if the private key is obtained by someone then they can use it to decrypt the data traffic.

Encryption is arguably the more important of the security meausures that SSL provides.

Server Authentication

SSL also provides the ability for a client to verify the identity of a server. This is used to protect against identity theft, where for example a malicious person imitates your server or redirects client traffic to a different server while pretending to be you.

Server authentication uses the signature aspect of public key cryptography. The private key is used to sign messages, and the public key is used to verify the signature. With SSL, the validity of signatures depends upon signing authorities. Signing authorites (also called certificate authorities) are companies who have generated public keys that are included with browser software. The browser knows it can trust the signing authority, and the signing authority signs your SSL certificate, putting its stamp of approval on the information in your certificate.

For example, after you generate your public and private key, you then generate a signing request and send it to a signing authority. This signing request contains information about your identity, this identity information is confirmed by the signing authority and ultimately displayed to the user of the browser. The signing authority validates the identity information you have provided and uses their private key to sign, and then returns a certificate to you. This certificate contains the identity information and your public key, verified by the signing authority, and is provided to the browser. Since the browser has the public key of the signing authority, it can recognize the signature and know that the identity information has been provided by someone that can be trusted.

OpenSSL

OpenSSL is the same SSL implementation that Apache's mod_ssl uses. Since OpenSSL uses the same certificate as Apache, you can get signed certificates using the same method as for Apache's mod_ssl or following the OpenSSL instructions.

Linking to the OpenSSL Libraries on Unix

On Unix systems, Resin's libexec/libresinssl.so JNI library supports SSL using the OpenSSL libraries. Although the ./configure script will detect many configurations, you can specify the openssl location directly:

resin> ./configure --with-openssl=/usr/local/ssl

Obtaining the OpenSSL Libraries on Windows

On Windows systems, the resinssl.dll includes JNI code to use OpenSSL libraries (it was in resin.dll in versions before 3.0). All you need to do is to obtain an OpenSSL binary distribution and install it.

Resin on Windows is compiled against the GnuWin32 binary, you can obtain an installation package here.

Once you have run the installation package, you can copy the necessary dll libraries into $RESIN_HOME:

C:\> cd %RESIN_HOME%
C:\resin-3.0> copy "C:\Program Files\GnuWin32\bin\libssl32.dll" .\libssl32.dll
C:\resin-3.0> copy "C:\Program Files\GnuWin32\bin\libeay32.dll" .\libeay32.dll

Preparing to use OpenSSL for making keys

You can make a keys/ subdirectory of $RESIN_HOME to do your work from and as a place to store your generated keys.

unix> cd $RESIN_HOME
unix> mkdir keys
unix> cd keys

win> cd %RESIN_HOME%
win> mkdir keys
win> cd keys

Using OpenSSL requires a configuration file. Unix users might find the default configuration file in /usr/ssl/openssl.cnf or /usr/share/ssl/openssl.cnf. Windows users may not have received one with their package.

Either way, it can be valuable to make your own openssl.cnf that is used just for generating the keys to use with Resin. You can use the following as a template for a file $RESIN_HOME/keys/openssl.cnf. You may want to fill in the _default values so you don't have to type them in every time.

[ req ]
 default_bits            = 1024
 distinguished_name      = req_distinguished_name

[ req_distinguished_name ]
 C                      = 2 letter Country Code, for example US
 C_default              =
 ST                     = State or Province
 ST_default             =
 L                      = City
 L_default              =
 O                      = Organization Name
 O_default              =
 OU                     = Organizational Unit Name, for example 'Marketing'
 OU_default             =
 CN                     = your domain name, for example www.hogwarts.com
 CN_default             =
 emailAddress           = an email address
 emailAddress_default   =

Creating a private key

Create a private key for the server. You will be asked for a password - don't forget it! You will need this password anytime you want to do anything with this private key. But don't pick something you need to keep secret, you will need to put this password in the Resin configuration file.

unix> openssl genrsa -des3 -out gryffindor.key 1024
win>  "C:\Program Files\GnuWin32\bin\openssl.exe" \
         genrsa -des3 -out gryffindor.key 1024

Creating a certificate

OpenSSL works by having a signed public key that corresponds to your private key. This signed public key is called a certificate. A certificate is what is sent to the browser.

You can create a self-signed certificate, or get a certificate that is signed by a certificate signer (CA).

Creating a self-signed certificate

You can create a certificate that is self-signed, which is good for testing or for saving you money. Since it is self-signed, browsers will not recognize the signature and will pop up a warning to browser users. Other than this warning, self-signed certificates work well. The browser cannot confirm that the server is who it says it is, but the data between the browser and the client is still encrypted.

unix> openssl req -config ./openssl.cnf -new -key gryffindor.key \
        -x509 -out gryffindor.crt
win> "C:\Program Files\GnuWin32\bin\openssl.exe" req -config ./openssl.cnf \
         -new -key gryffindor.key -x509 -out gryffindor.crt

You will be asked to provide some information about the identity of your server, such as the name of your Organization etc. Common Name (CN) is your domain name, like: "www.gryffindor.com".

Creating a certificate request

To get a certificate that is signed by a CA, first you generate a certificate signing request (CSR).

unix> openssl req -new -config ./openssl.cnf -key gryffindor.key \
      -out gryffindor.csr
win> "C:\Program Files\GnuWin32\bin\openssl.exe" req -new \
      -config ./openssl.cnf  -key gryffindor.key -out gryffindor.csr

You will be asked to provide some information about the identity of your server, such as the name of your Organization etc. Common Name (CN) is your domain name, like: "www.gryffindor.com".

Send the CSR to a certificate signer (CA). You'll use the CA's instructions for Apache because the certificates are identical. Some commercial signers include:

• Verisign
• Thawte Consulting

You'll receive a gryffindor.crt file.

Most browsers are configured to recognize the signature of signing authorities. Since they recognize the signature, they will not pop up a warning message the way they will with self-signed certificates. The browser can confirm that the server is who it says it is, and the data between the browser and the client is encrypted.

resin.conf - Configuring Resin to use your private key and certificate

The OpenSSL configuration has two tags certificate-file and certificate-key-file. These correspond exactly to mod_ssl's SSLCertificateFile and SSLCertificateKeyFile. So you can use the same certificates (and documentation) from mod_ssl for Resin.

The full set of parameters is in the port configuration.

...
<http port="443">
  <openssl>
    <certificate-file>keys/gryffindor.crt</certificate-file>
    <certificate-key-file>keys/gryffindor.key</certificate-key-file>
    <password>my-password</password>
  </openssl>
</http>

Testing

Testing with the browser

A quick test is the following JSP.

Secure? <%= request.isSecure() %>

Using openssl to test the server

The openssl tool can be used as a client, showing some interesting information about the conversation between the client and the server:

unix$ openssl s_client -connect www.some.host:443 -prexit

Certificate Chains

A certificate chain is used when the signing authority is not an authority trusted by the browser. In this case, the signing authority uses a certificate which is in turn signed by a trusted authority, giving a chain of [your certificate] <--- signed by ---- [untrusted signer] <---- signed by ---- [trusted signer].

The Resin config parameter certificate-chain-file is used to specify a certificate chain. It is used to reference a file that is a concatenation of:

1. your certificate file
2. the intermediate (untrusted) certificate
3. the root (trusted) certificate.

The certificates must be in that order, and must be in PEM format.

Example certificate chain for Instant SSL

Comodo (http://instantssl.com) is a signing authority that is untrusted by most browsers. Comodo has their certificate signed by GTECyberTrust.

Comodo gives you three certificates:

1. your_domain.crt (signed by Comodo)
2. ComodoSecurityServicesCA.crt (signed by GTE CyberTrust)
3. GTECyberTrustRoot.crt (universally known root)

In addition to this, you have your key, your_domain.key. The contents of the file referred to by certificate-chain-file is a concatenation of the three certificates, in the correct order.

$ cat your_domain.crt ComodoSecurityServicesCA.crt GTECyberTrustRoot.crt > chain.txt

<http port="443">
  <openssl>
    <certificate-key-file>keys/your_domain.key</certificate-key-file>
    <certificate-file>keys/your_domain.crt</certificate-file>        
    <certificate-chain-file>keys/chain.txt</certificate-chain-file>
    <password>test123</password>
  </openssl>
</http>

JSSE

We recommend avoiding JSSE if possible. It is slower than using Resin's OpenSSL support and does not appear to be as stable as Apache or IIS (or Netscape/Zeus) for SSL support. In addition, JSSE is far more complicated to configure. While we've never received any problems with Resin using OpenSSL, or SSL from Apache or IIS, JSSE issues are fairly frequent.

Install JSSE from Sun

This section gives a quick guide to installing a test SSL configuration using Sun's JSSE. It avoids as many complications as possible and uses Sun's keytool to create a server certificate.

Resin's SSL support is provided by Sun's JSSE. Because of export restrictions, patents, etc, you'll need to download the JSSE distribution from Sun or get a commercial JSSE implementation.

More complete JSSE installation instructions for JSSE are at http://java.sun.com/products/jsse/install.html.

1. First download Sun's JSSE.
2. Uncompress and extract the downloaded file.
3. Install the JSSE jar files: jsse.jar, jnet.jar, and jcert.jar. You can either put them into the CLASSPATH or you can put them into $JAVA_HOME/jre/lib/ext. Since you will use "keytool" with the new jars, you need to make them visible to keytool. Just adding them to resin/lib is not enough.
4. Register the JSSE provider (com.sun.net.ssl.internal.ssl.Provider). Modify $JAVA_HOME/jre/lib/security/java.security so it contains something like:

   security.provider.1=sun.security.provider.Sun
   security.provider.2=com.sun.net.ssl.internal.ssl.Provider
   

   Adding the JSSE provider allows "keytool" to create a key using the RSA algorithm.

Create a test server certificate

The server certificate is the core of SSL. It will identify your server and contain the secret key to make encryption work.

• Sun's keytool
• A self-signed certificate using open_ssl
• A test certificate from Thawte
• A production certificate from one of the certificate authorities (Verisign, Thawte, etc)

In this case, we're using Sun's keytool to generate the server certificate. Here's how:

resin1.2.b2> mkdir keys
resin1.2.b2> keytool -genkey -keyalg RSA -keystore keys/server.keystore
Enter keystore password:  changeit
What is your first and last name?
  [Unknown]:  www.caucho.com
What is the name of your organizational unit?
  [Unknown]:  Resin Engineering
What is the name of your organization?
  [Unknown]:  Caucho Technology, Inc.
What is the name of your City or Locality?
  [Unknown]:  San Francisco
What is the name of your State or Province?
  [Unknown]:  California
What is the two-letter country code for this unit?
  [Unknown]:  US
Is <CN=www.caucho.com, OU=Resin Engineering,
  O="Caucho Technology, Inc.", L=San Francisco, ST=California, C=US> correct?
  [no]:  yes

Enter key password for <mykey>
        (RETURN if same as keystore password):  changeit

Currently, the key password and the keystore password must be the same.

resin.conf

The Resin SSL configuration extends the http configuration with a few new elements.

<resin xmlns="http://caucho.com/ns/resin">
  <server>

    <http port="8443">
     <jsse-ssl>
       <key-store-type>jks</key-store-type>
       <key-store-file>keys/server.keystore</key-store-file>
       <password>changeit</password>
     </jsse-ssl>
    </http>

    ...

  </http-server>
</caucho.com>

Testing JSSE

With the above configuration, you can test SSL with https://localhost:8443. A quick test is the following JSP.

Secure? <%= request.isSecure() %>

User Experiences with JSSE

How do I configure Resin with SSL using JSSE?

Nicholas Lehuen writes:

Here is a short step-by-step installation guide for SSL on Resin.

The purpose : to install SSL support on Resin

Requirements

• The latest Resin 1.2 snapshot (I used the 08/04/2000 snapshot with success) http://www.caucho.com/download/index.xtp
• JSSE 1.0.1 http://java.sun.com/products/jsse/
• Optional : a certificate authority (CA) such as Verisign, Thawte, or your own. Thawte is providing a free test certificate authority service which enables you to check the certification process before buying your own certificate. Of course, you can also skip the CA by providing self-signed public key certificate. This will be explained later. https://www.thawte.com/cgi/server/test.exe

JSSE setup

1. Follow the installation instructions http://java.sun.com/products/jsse/install.html
2. Even if Resin has its own provider registration system (we'll see it on next step), I suggest that you statically register the SunJSSE by editing the <java-home>/lib/security/java.security as explained in the installation guide. This will ease the use of keytool.

Keystore initialization

1. Create a directory named 'keys' somewhere in your Resin installation. I suggest you place it in the Resin home directory.
2. Copy the file <java-home>/lib/security/cacerts into the 'keys' directory
3. Rename the cacerts file as you want. I'll suppose you name it 'private.keystore'.

Keystore protection

Your private.keystore file is for the moment a copy of the cacerts keystore, which contains the CA public key certificates (very important for client HTTPS connections). We will insert your own private key in this file, thus it'll have to be password-protected, so that anyone stealing it will have difficulties in forging certificates on your behalf.

1. Go into the 'keys' directory
2. type the following command : keytool -storepasswd -storepass changeit -new YourPasswordHere \ -keystore private.keystore

(the default password for the cacerts keystore is 'changeit')

Private key generation

We'll now generate your key pair, which is composed of a private (the one which MUST remain secret !) and a public key. The point here is to use the RSA key pair generator, and NOT the default one, which is DSA. This is were the JSSE security provider is used.

type the following command :

M:\keys>keytool -genkey -keyalg RSA -alias myserverkeypair \
                -storepass YourPasswordHere -keystore private.keystore
What is your first and last name?
  [Unknown]:  www.myserver.com
What is the name of your organizational unit?
  [Unknown]:  Foo Dept
What is the name of your organization?
  [Unknown]:  Bar
What is the name of your City or Locality?
  [Unknown]:  Paris
What is the name of your State or Province?
  [Unknown]:  France
What is the two-letter country code for this unit?
  [Unknown]:  FR
Is <CN=www.myserver.com, OU=Foo Dept, O=Bar, L=Paris,
                ST=France, C=FR> correct?
  [no]:  yes
 
Enter key password for <myserverkeypair>
        (RETURN if same as keystore password):

You MUST mention your HTTP server name as the CN of the certificate (thus the reply to 'first and last name'). Browsers would emit warnings to your users if you didn't. Any other informations are at your choice, however the process of key pair generation and attributes definitions is very strict for "real-life" cryptography, i.e. Verisign will double-check your identity, address and so on.

Another important point : DON'T AFFECT A PASSWORD to your key pair. It must remain the same as the keystore, at least until Resin provides a means of configuring the key pair password.

Public Key Certificate (optional)

Request a public key certificate and insert the public key certificate into your keystore.

For users to trust your server, you'll have to have your public key certificate (PKC) signed by a Certificate Authority (CA) (Verisign, Thawte, Certplus...). This is done by sending a certificate signature request (CSR) to the CA, coping with all the legal stuff and getting a signed PKC in return. This step is mandatory for production server, unless you have some means to convince your users that your PKC is valid without a CA signature, which is possible in intranet environment for example. However, for testing purpose, you can start by using your self-signed PKC without any CA signature. An intermediary solution is to use a test CA so that you can check that your CSR is correctly emitted, that the Certificate Chain is correctly checked, and so on. Thawte provides a test CA at the address mentioned above.

1. Generate a CSR by typing the following command :

   
   M:\keys>keytool -certreq -alias myserverkeypair -storepass YourPasswordHere \
                   -keystore private.keystore
   -----BEGIN NEW CERTIFICATE REQUEST-----
   MIIBqjCCARMCAQAwajELMAkGA1UEBhMCRlIxDzANBgNVBAgTBkZyYW5jZTEOMAwGA1UEBxMFUGFy
   ... cut ...
   KDYZTklbg1NOiXTdXIhPHb3+YOgZ+HoeDTxOx/rRhA==
   -----END NEW CERTIFICATE REQUEST-----
   

2. Copy/Paste the CSR into the text box at the following address. Leave all options with their default value. https://www.thawte.com/cgi/server/test.exe
3. You'll get a certificate looking like :

   -----BEGIN CERTIFICATE-----
   MIICjzCCAfigAwIBAgIDBp8SMA0GCSqGSIb3DQEBBAUAMIGHMQswCQYDVQQGEwJa
   ... cut ...
   /93Q58iI4fgQ/kc+l8ogpVwh/IJw1Ujmszd19Jf+pxyySMM=
   -----END CERTIFICATE-----
   

4. Copy/Paste this certificate into a file named 'myserver.cer' . If you have Microsoft Internet Explorer 5.0 (maybe 4.0) installed, you can open this .cer file and see the certificate as your user will when they ask the security properties of pages served securely by your server. A warning should be emitted, stating that you can't trust the certificate as it does not point to a trusted root CA. You can keep going with this warning or download and trust the test root CA (available on https://www.thawte.com/servertest.crt ). Be ware though that the final user should not and surely won't accept to trust this test root CA.
5. Anyway, to be able to import your signed certificate, you'll have to import the test root CA certificate. Download it and import it using the following command :

   M:\keys>keytool -import -alias servertest -storepass YourPasswordHere \
                   -keystore private.keystore -file servertest.crt
   Owner: CN=Thawte Test CA Root, OU=TEST, O=Thawte, ST=FOR TESTING, C=ZA
   Issuer: CN=Thawte Test CA Root, OU=TEST, O=Thawte, ST=FOR TESTING, C=ZA
   Serial number: 0
   Valid from: Thu Aug 01 02:00:00 CEST 1996 until: Thu Dec 31 22:59:59 CET 2020
   Certificate fingerprints:
            MD5:  5E:E0:0E:1D:17:B7:CA:A5:7D:36:D6:02:DF:4D:26:A4
            SHA1: 39:C6:9D:27:AF:DC:EB:47:D6:33:36:6A:B2:05:F1:47:A9:B4:DA:EA
   Trust this certificate? [no]:  yes
   Certificate was added to keystore
   

6. Import the certificate and attach it to your server key pair by typing the command :

   M:\keys>keytool -import -alias myserverkeypair -storepass YourPasswordHere \
                   -keystore private.keystore -file myserver.cer
   Certificate reply was installed in keystore
   

Key pair verification

Issue the following command :

M:\keys>keytool -list -v -alias myserverkeypair -storepass YourPasswordHere \
                -keystore private.keystore
Alias name: myserverkeypair
Creation date: Fri Aug 11 23:07:53 CEST 2000
Entry type: keyEntry
Certificate chain length: 2
Certificate[1]:
Owner: CN=www.myserver.com, OU=Foo Dept, O=Bar, L=Paris, ST=France, C=FR
Issuer: CN=Thawte Test CA Root, OU=TEST, O=Thawte, ST=FOR TESTING, C=ZA
Serial number: 69f12
Valid from: Fri Aug 11 23:00:07 CEST 2000 until: Mon Sep 11 23:00:07 CEST 2000
Certificate fingerprints:
         MD5:  41:84:55:8C:A1:85:28:DA:B0:5A:47:D6:5B:D2:ED:41
         SHA1: 61:DE:DB:E6:7C:3C:AD:90:63:9B:20:E0:FF:3B:02:3A:60:EB:B4:82
Certificate[2]:
Owner: CN=Thawte Test CA Root, OU=TEST, O=Thawte, ST=FOR TESTING, C=ZA
Issuer: CN=Thawte Test CA Root, OU=TEST, O=Thawte, ST=FOR TESTING, C=ZA
Serial number: 0
Valid from: Thu Aug 01 02:00:00 CEST 1996 until: Thu Dec 31 22:59:59 CET 2020
Certificate fingerprints:
         MD5:  5E:E0:0E:1D:17:B7:CA:A5:7D:36:D6:02:DF:4D:26:A4
         SHA1: 39:C6:9D:27:AF:DC:EB:47:D6:33:36:6A:B2:05:F1:47:A9:B4:DA:EA

As you can see the alias myserverkeypair points to a keyEntry type entry, its certificate chain has 2 certificate, the first being your own certificate, signed by the Thawte Test CA Root, and the other being the Thawte Test CA Root own.

Resin configuration (resin.conf)

add the support for the SunJSSE security provider :

<resin xmlns="http://caucho.com/ns/resin">
    <security-provider id='com.sun.net.ssl.internal.ssl.Provider'/>
 
<!-- declare a new HTTP server on port 443 (standard port for HTTPS),
      - with SSL enabled -->
 
<server>
  <!-- the http port -->
  <http port="80"/>

  <!-- the srun port, read by both JVM and plugin -->
  <cluster>
    <srun host='localhost' port='6802'/>
  </cluster>
 
  <http port=443>
    <jsse-ssl>
      <key-store-type>jks</key-store-type>
      <key-store-file>file://m:/keys/private.keystore</key-store-file>
      <password>YourPasswordHere</password>
    </jsse-ssl>
  </http>

Test !

Try connecting to your server with https instead of http !

I've been running successfully SSL on Resin with JDK 1.3 on Windows NT 4 SP6 and JDK 1.2.2 on Solaris 7.

And the fun begins when mixing HTTPS and WAP... !