Chapter 6. Configuring Applications for Single Sign-On

6.1. Configuring Firefox to Use Kerberos for Single Sign-On
6.2. Enabling Smart Card Login on Red Hat Enterprise Linux
6.3. Setting up Browsers to Support SSL for Tokens
6.4. Using the Certificates on Tokens for Mail Clients

After a smart card is enrolled, the smart card can be used for SSL client authentication and S/MIME email applications. The PKCS #11 module used by these applications, by default, is located in /usr/lib/libcoolkeypk11.so.

6.1. Configuring Firefox to Use Kerberos for Single Sign-On

Firefox can use Kerberos for single sign-on to intranet sites and other protected websites. For Firefox to use Kerberos, it first has to be configured to send Kerberos credentials to the appropriate KDC.

In the address bar of Firefox, type about:config to display the list of current configuration options.
In the Filter field, type negotiate to restrict the list of options.
Double-click the network.negotiate-auth.trusted-uris entry.
Enter the name of the domain against which to authenticate.
Next, configure the network.negotiate-auth.delegation-uris entry, using the same domain as for network.negotiate-auth.trusted-uris.

NOTE

Even after Firefox is configured to pass Kerberos credentials, it still requires a valid Kerberos ticket to use. To generate a Kerberos ticket, use the kinit command and supply the user password for the user on the KDC.

[jsmith@host ~] $ kinit
Password for [email protected]:

If Kerberos authentication is not working, turn on verbose logging for the authentication process.

Close all instances of Firefox.

In a command prompt, export values for the NSPR_LOG_* variables:

export NSPR_LOG_MODULES=negotiateauth:5
export NSPR_LOG_FILE=/tmp/moz.log

Restart Firefox from that shell, and visit the website where Kerberos authentication is failing.
Check the /tmp/moz.log file for error messages with nsNegotiateAuth in the message.

There are several common errors that occur with Kerberos authentication.

The first error says that no credentials have been found.
```
-1208550944[90039d0]: entering nsNegotiateAuth::GetNextToken()
-1208550944[90039d0]: gss_init_sec_context() failed: Miscellaneous failure
No credentials cache found
```
This means that there are no Kerberos tickets (meaning that they expired or were not generated). To fix this, run kinit to generate the Kerberos ticket and then open the website again.
The second potential error is if the browser is unable to contact the KDC, with the message Server not found in Kerberos database.
```
-1208994096[8d683d8]: entering nsAuthGSSAPI::GetNextToken()
-1208994096[8d683d8]: gss_init_sec_context() failed: Miscellaneous failure
Server not found in Kerberos database
```
This is usually a Kerberos configuration problem. The correct entries must be in the [domain_realm] section of the /etc/krb5.conf file to identify the domain. For example:
```
.example.com = EXAMPLE.COM
example.com = EXAMPLE.COM
```
If there are no errors in the log, then the problem could be that an HTTP proxy server is stripping off the HTTP headers required for Kerberos authentication. Try to connect to the site using HTTPS, which allows the request to pass through unmodified.