The following sections explain how to set up single sign-on (SSO) with Microsoft clients, using Windows authentication based on the Simple and Protected Negotiate (SPNEGO) mechanism and the Kerberos protocol, together with the WebLogic Negotiate Identity Assertion provider.
Configuring Microsoft Clients to Use Windows Integrated Authentication
Using Startup Arguments for Kerberos Authentication with WebLogic Server
Single sign-on (SSO) with Microsoft clients allows cross-platform authentication between Web applications or Web services running in a WebLogic domain and .NET Web service clients or browser clients (for example, Internet Explorer) in a Microsoft domain. The Microsoft clients must use Windows authentication based on the Simple and Protected Negotiate (SPNEGO) mechanism.
Cross-platform authentication is achieved by emulating the negotiate behavior of native Windows-to-Windows authentication services that use the Kerberos protocol. In order for cross-platform authentication to work, non-Windows servers (in this case, WebLogic Server) need to parse SPNEGO tokens in order to extract Kerberos tokens which are then used for authentication.
For more information about Windows and Kerberos, see http://technet.microsoft.com/en-us/library/bb742431.aspx.
To use SSO with Microsoft clients you need:
A host computer with:
Windows 2000 or later installed
Fully-configured Active Directory authentication service. Specific Active Directory requirements include:
User accounts for mapping Kerberos services
Service Principal Names (SPNs) for those accounts
Key tab files created and copied to the start-up directory in the WebLogic domain
WebLogic Server installed and configured properly to authenticate through Kerberos, as described in this chapter
Client systems with:
Windows 2000 Professional SP2 or later installed
One of the following types of clients:
A properly configured Internet Explorer browser. Internet Explorer 6.01 or later is supported.
.NET Framework 1.1 and a properly configured Web service client.
Clients must be logged on to a Windows 2000 domain and have Kerberos credentials acquired from the Active Directory server in the domain. Local logins will not work.
Configuring SSO with Microsoft clients requires set-up procedures in the Microsoft Active Directory, the client, and the WebLogic domain. (These procedures are detailed in the sections that follow.)
Define a principal in Active Directory to represent the WebLogic Server. The Kerberos protocol uses the Active Directory server in the Microsoft domain to store the necessary security information.
Any Microsoft client you want to access in the Microsoft domain must be set up to use Windows Integrated authentication, sending a Kerberos ticket when available.
In the security realm of the WebLogic domain, configure a Negotiate Identity Assertion provider. The Web application or Web service used in SSO needs to have authentication set in a specific manner. A JAAS login file that defines the location of the Kerberos identification for WebLogic Server must be created.
To configure SSO with Microsoft clients:
Configure your network domain to use Kerberos. See Configuring Your Network Domain to Use Kerberos.
Create a Kerberos identification for WebLogic Server.
Create a user account in the Active Directory for the host on which WebLogic Server is running.
Create a Service Principal Name for this account.
Create a user mapping and keytab file for this account.
Choose a Microsoft client (either a Web service or a browser) and configure it to use Windows Integrated authentication. See Configuring Microsoft Clients to Use Windows Integrated Authentication.
Set up the WebLogic domain to use Kerberos authentication.
Create a JAAS login file that points to the Active Directory server in the Microsoft domain and the keytab file created in Step 1. See Creating a JAAS Login File.
Configure a Negotiate Identity Assertion provider in the WebLogic Server security realm. See Configuring a Negotiate Identity Assertion Provider.
Start WebLogic Server using specific start-up arguments. See Using Startup Arguments for Kerberos Authentication with WebLogic Server.
The following sections describe these steps in detail.
A Windows domain controller can serve as the Kerberos Key Distribution Center (KDC) server for Kerberos-based client and host systems. On any domain controller, the Active Directory and the Kerberos services are running automatically.
Java GSS requires a Kerberos configuration file. The default name and location of the Kerberos configuration file depends on the operating system being used. Java GSS uses the following order to search for the default configuration file:
The file referenced by the Java property java.security.krb5.conf.
${java.home}/lib/security/krb5.conf.
%windir%\krb5.ini on Microsoft Windows platforms.
/etc/krb5/krb5.conf on Solaris platforms.
/etc/krb5.conf on other Unix platforms.
To configure Kerberos in your Windows domain controller, you need to configure each machine that will access the KDC to locate the Kerberos realm and available KDC servers. For example:
Example 6-1 Sample krb5.ini File
[libdefaults] default_realm = MYDOM.COM (Identifies the default realm. Set its value to your Kerberos realm) default_tkt_enctypes = des-cbc-crc default_tgs_enctypes = des-cbc-crc ticket_lifetime = 600 [realms] MYDOM.COM = { kdc = <IP address for MachineA> (host running the KDC) (For Unix systems, you need to specify port 88, as in <IP-address>:88) admin_server = MachineA default_domain = MYDOM.COM } [domain_realm] .mydom.com = MYDOM.COM [appdefaults] autologin = true forward = true forwardable = true encrypt = true
Active Directory provides support for service principal names (SPN), which are a key component in Kerberos authentication. SPNs are unique identifiers for services running on servers. Every service that uses Kerberos authentication needs to have an SPN set for it so that clients can identify the service on the network. An SPN usually looks something like [email protected]. You need to define an SPN to represent your WebLogic Server in the Kerberos realm. If an SPN is not set for a service, clients have no way of locating that service. Without correctly set SPNs, Kerberos authentication is not possible. Keytab files are the mechanism for storing the SPNs. Keytab files are copied to the WebLogic domain and are used in the login process. This configuration step describes how to create an SPN, user mapping, and keytab file for WebLogic Server.
This configuration process requires the use of the following Active Directory utilities:
setspn—Windows 2000 Resource Kit
ktpass—Windows 2000 distribution CD in Program Files\Support Tools
Note:
Thesetspn and ktpass Active Directory utilities are products of Microsoft. Therefore, Oracle does not provide complete documentation for this utilities. For more information, see the appropriate Microsoft documentation.The process for creating a Kerberos identification consists of the following steps:
"Step 2: Configure the User Account to Comply with Kerberos"
"Step 3: Define a Service Principal Name and Create a Keytab for the Service"
In the Active Directory server, create a user account for the host computer on which WebLogic Server runs. (Select New > User, not New > Machine.)
When creating the user account, use the simple name of the computer. For example, if the host is named myhost.example.com, create a user in Active Directory called myhost.
Note the password you defined when creating the user account. You will need it for the instructions described in Step 3: Define a Service Principal Name and Create a Keytab for the Service. Do not select the User must change password at next logon option or any other password options.
Configure the new user account to comply with the Kerberos protocol as follows. The user account's encryption type must be DES and the account must require Kerberos pre-authentication.
Note:
If you are running WebLogic Server on Windows 2003 and the IBM JDK 6, the user account's encryption type must be RC4-HMAC.Right-click the name of the user account in the Users tree in the left pane and select Properties.
Select the Account tab and check the box Use DES encryption types for this account. Make sure no other boxes are checked, particularly the box "Do not require Kerberos pre-authentication."
Click OK.
Caution:
Setting the encryption type may corrupt the password. Therefore, reset the user password by right-clicking the name of the user account, selecting Reset Password, and re-entering the password created in Step 1: Create a User Account for the Host Computer.As mentioned in Creating a Kerberos Identification for WebLogic Server, an SPN is a unique name that identifies an instance of a service and is associated with the logon account under which the service instance runs. The SPN is used in the process of mutual authentication between the client and the server hosting a particular service. The client finds a computer account based on the SPN of the service to which it is trying to connect. So, in a specific project, you need to link the service that will be invoked by your WebLogic clients to the account you just defined for your WebLogic Server. For example, the service invoked by the WebLogic browser clients is HTTP/myhost.example.com, which needs to be linked to the myhost account.
Windows account names are not multipart as Kerberos principal names. Because of this, it is not possible to directly create an account using the name HTTP/hostname.dns.com. Such a principal instance is created through service principal name mappings. In this case, an account is created with a meaningful name hostname, and a service principal name mapping is added for HTTP/hostname.dns.com.
The specific steps for defining an SPN and creating a keytab for the service depend on the underlying platform on which WebLogic Server is running. They are provided in the following sections:
If WebLogic Server runs on a Windows system, complete the following steps:
Use the setspn utility to create the SPN for the HTTP service for the WebLogic Server account created in Step 1. For example:
setspn -A HTTP/myhost.example.com myhost
Identify the SPNs that are associated with your user account by entering the setspn -L command. For example:
setspn -L myhost
Tip:
The preceding is an important step. If the same service is linked to a different account in the Active Directory server, the client will not send a Kerberos ticket to the server.Use the ktab utility to create a keytab to be exported to the WebLogic Server machine. The command to run the ktab utility has the following syntax (note that the Kerberos realm name must be entered in all uppercase):
ktab -k keytab-file-name -a account-name@REALM.NAME
For example:
ktab -k mykeytab -a [email protected]
When prompted for a password, enter the password created in Step 1.
Save the keytab file in a secure location and export it to the domain directory of your WebLogic Server instance (for example, to myhost).
If WebLogic Server runs on a UNIX system, create an SPN and a keytab file for the HTTP service for the WebLogic Server account by using the ktpass command-line tool. This tool enables an administrator to configure a non-Windows Server Kerberos service as a security principal in the Windows Server Active Directory.
The ktpass command configures the server principal name for the service in Active Directory and generates a Kerberos keytab file containing the shared secret key of the service. The tool allows UNIX-based services that support Kerberos authentication to use the interoperability features provided by the Windows Server Kerberos KDC service.
The ktpass command has the following syntax:
ktpass -princ HTTP/hostname@REALM-NAME -mapuser account-name -pass password -out keytab-file-name
For example:
ktpass -princ HTTP/[email protected] -mapuser myhost -pass welcome1 -out mykeytab
Note:
Thektpass command changes the principal name in the Active Directory server from account-name to HTTP/account-name. Consequently, the keytab file is generated for a principal named HTTP/account-name. However, sometimes the name change does not happen. If not, you should change it manually in the Active Directory server; otherwise the keytab you generate will not work properly.
To modify the user logon name manually:
Right-click on the user node, select Properties, and click on the Account tab.
Export the generated keytab file to your Unix machine hosting the WebLogic Server in the WebLogic domain directory.
Use the kinit utility to verify that Kerberos is set up properly and that your principal and keytab are valid.
The kinit utility is provided by the JRE and may be used to obtain and cache Kerberos ticket-granting tickets. You can run the kinit utility by entering the following command:
kinit -k -t keytab-file account-name
The output should be similar to the following:
New ticket is stored in cache file C:\Documents and Settings\Username\krb5cc_myhost
Ensure the Microsoft client you want to use for single sign-on is configured to use Windows Integrated authentication. The following sections describe how to configure a .NET Web server, an Internet Explorer browser client, and a Mozilla Firefox client to use Windows Integrated authentication:
To configure a .NET Web service to use Windows authentication:
In the web.config file for the Web service, set the authentication mode to Windows for IIS and ASP.NET as follows:
<authentication mode="Windows" />
This setting is usually the default.
Add the statement needed for the Web services client to pass to the proxy Web service object so that the credentials are sent through SOAP.
For example, if you have a Web service client for a Web service that is represented by the proxy object conv, the syntax is as follows:
/* * Explicitly pass credentials to the Web Service */ conv.Credentials = System.Net.CredentialCache.DefaultCredentials;
To configure an Internet Explorer browser to use Windows authentication, follow these procedures in Internet Explorer.
In Internet Explorer, select Tools > Internet Options.
Select the Security tab.
Select Local intranet and click Sites.
In the Local intranet popup, ensure that the "Include all sites that bypass the proxy server" and "Include all local (intranet) sites not listed in other zones" options are checked.
Click Advanced.
In the Local intranet (Advanced) dialog box, add all relative domain names that will be used for WebLogic Server instances participating in the SSO configuration (for example, myhost.example.com) and click OK.
Select Tools > Internet Options.
Select the Security tab.
Select Local intranet and click Custom Level... .
In the Security Settings dialog box, scroll to the User Authentication section.
Select Automatic logon only in Intranet zone. This option prevents users from having to re-enter logon credentials, which is a key piece to this solution.
Click OK.
If you have a proxy server enabled:
Select Tools > Internet Options.
Select the Connections tab and click LAN Settings.
Verify that the proxy server address and port number are correct.
Click Advanced.
In the Proxy Settings dialog box, ensure that all desired domain names are entered in the Exceptions field.
Click OK to close the Proxy Settings dialog box.
In addition to the settings already described, one additional setting is required if you are running Internet Explorer 6.0.
In Internet Explorer, select Tools > Internet Options.
Select the Advanced tab.
Scroll to the Security section.
Make sure that Enable Integrated Windows Authentication option is checked and click OK.
If this option was not checked, restart the computer.
To configure a Firefox browser to use Windows Integrated authentication, complete the following steps:
Start Firefox.
Enter about:config in the Location Bar.
Enter the filter string network.negotiate.
Set the preferences as shown in Table 6-1.
Table 6-1 Preferences Required in Firefox for Windows Integrated Authentication
| Preference Name | Status | Type | Value |
|---|---|---|---|
network.negotiate-auth.allow-proxies |
default |
boolean |
true |
network.negotiate-auth.delegation-uris |
user set |
string |
http://,https:// |
network.negotiate-auth.gsslib |
default |
string |
<blank>Foot 1 |
network.negotiate-auth.trusted-uris |
user set |
string |
http://,https:// |
network.negotiate-auth.using-native-gsslib |
default |
boolean |
true |
Footnote 1 The value for the network.negotiate-auth.gsslib preference should be kept blank.
If you are running WebLogic Server on either the Windows or UNIX platforms, you need a JAAS login file. The JAAS login file tells the WebLogic Security Framework to use Kerberos authentication and defines the location of the keytab file which contains Kerberos identification information for WebLogic Server. You specify the location of the JAAS login file in the java.security.auth.login.config startup argument for WebLogic Server, as described in Using Startup Arguments for Kerberos Authentication with WebLogic Server.
Notes:
For JDK 5.0 and JDK 1.4, the JAAS Login Entry names arecom.sun.security.jgss.initiate and com.sun.security.jgss.accept.
For JDK 6.0, the JAAS Login Entry names were changed to com.sun.security.jgss.krb5.initiate and com.sun.security.jgss.krb5.accept.
Example 6-2 contains a sample JAAS login file for Kerberos authentication. Significant sections are shown in bold.
Example 6-2 Sample JAAS Login File for Kerberos Authentication
com.sun.security.jgss.krb5.initiate {
com.sun.security.auth.module.Krb5LoginModule required
principal="[email protected]" useKeyTab="true"
keyTab="mykeytab" storeKey="true";
};
com.sun.security.jgss.krb5.accept {
com.sun.security.auth.module.Krb5LoginModule required
principal="[email protected]" useKeyTab="true"
keyTab="mykeytab" storeKey="true";
};
For the principal option, specify the value of the userPrincipalName attribute of the account under which the service is running. (Incorrectly specifying the user principal name results in an error such as "Unable to obtain password from user.")
The keytab file specified in the keytab option must be accessible by the WebLogic Server process. Ensure that the appropriate permissions are set. If you are unsure of the search path WebLogic Server is using, provide the absolute path to the file. Make sure you enclose the path in double quotes, and replace any backslash (\) in the path with a double backslash (\\) or a forward slash (/).
WebLogic Server includes a security provider, the Negotiate Identity Assertion provider, to support single sign-on (SSO) with Microsoft clients. This identity assertion provider decodes Simple and Protected Negotiate (SPNEGO) tokens to obtain Kerberos tokens, validates the Kerberos tokens, and maps Kerberos tokens to WebLogic users. You need to configure a Negotiate Identity Assertion provider in your WebLogic security realm in order to enable SSO with Microsoft clients. See Configuring a Negotiate Identity Assertion Provider and "Configure Authentication and Identity Assertion providers" in the Oracle WebLogic Server Administration Console Help.
To use Kerberos authentication with WebLogic Server, use the following start-up arguments when you start WebLogic Server:
-Djavax.security.auth.useSubjectCredsOnly=false -Djava.security.auth.login.config=krb5Login.conf -Djava.security.krb5.realm=Example.CORP -Djava.security.krb5.kdc=ADhostname
where
javax.security.auth.useSubjectCredsOnly specifies that it is permissible to use an authentication mechanism other than Subject credentials.
java.security.auth.login.config specifies the JAAS login file, krb5Login.conf, described in Creating a JAAS Login File.
java.security.krb5.realm defines the Microsoft domain in which the Active Directory server runs.
java.security.krb5.kdc defines the host name on which the Active Directory server runs.
Java GSS messages are often very useful during troubleshooting, so you might want to add -Dsun.security.krb5.debug=true as part of the initial setup.
To verify that SSO with Microsoft clients is configured properly, point a browser (that you have configured as described in Configuring an Internet Explorer Browser) to the Microsoft Web application or Web service you want to use. If you are logged on to a Windows domain and have Kerberos credentials acquired from the Active Directory server in the domain, you should be able to access the Web application or Web service without providing a username or password.