Difference between revisions of "VOMS-API"

Latest revision as of 13:27, 5 June 2009

The VOMS-API library

The library offers a number of facilities for interacting with VOMS server. [Installation procedure]

Last version of this library allows to programmatically manage a VO in a VOMS server installation from both a generic Java client and a gcube service.

VOMS-API library allows to invoke 3 different VOMS wsdl-based web interfaces:

• glite-security-voms-admin-2.0.2.wsdl
• glite-security-voms-acl-2.0.2.wsdl
• glite-security-voms-attributes-2.0.2.wsdl

VOMS Admin

VOMS-Admin interface is in charge for the administrative actions. Through this you can add/remove user, create/delete groups ecc. The VOMS-API library offers two different VOMSAdmin implementations. These two different implementation are basically useful to invoke VOMS admin interface from a gContainer of from a standard java client, VOMSADminGT4 or VOMSAdminImpl, respectively.

These implementations wrap two different portTypes (standard and extende) to access these functionalities:

• the standard portType implements all the VOMS-Admin operations provided by glite-security-voms-admin-2.0.2.wsdl.
• the extended portType offers a number of customized gCube operations built on top of the standard one. Some operations are overloaded in order to simplify management of the users with a proxy certificate provided by gCube SimpleCA.

Both classes (VOMSAdminImpl and VOMSAdminGT4) can be instantiate in three different ways: by default they will use host credentials contained in /etc/grid-security/hostpubliccert.pem and /etc/grid-security/hostprivatekey.pem.

Alternatively a user can specify his own credentials:

• a user can specify CLIENT creds by indicating the triple (CLIENT_CERT, CLIENT_KEY, CLIENT_PWD) or
• a user can specify CLIENT creds by indicating a CLIENT_PROXY, that's a proxy certificate of the pem cerficates.

as described at [vomsAPI.properties example]

VOMS-Admin sample usage

These two classes are, respectively, a usage example of VOMSAdminImpl class and CredentialsManagerImpl.

Usage Examples from inside a gContainer

User user = new User();
user.setDN(dn);
user.setCA(ca);
user.setCN(username);
user.setMail(email);
VOMSAdminGT4 vomsAdminGT4 = new VOMSAdminGT4("/path/to/vomsAPI.properties");
 
// credentials
((Stub) vomsAdminGT4)._setProperty(GSIConstants.GSI_CREDENTIALS, credentials);
 
// Authentication method
((Stub) vomsAdminGT4)._setProperty(org.globus.wsrf.impl.security.authentication.Constants.GSI_TRANSPORT, org.globus.wsrf.impl.security.authentication.Constants.ENCRYPTION);
// delegation
((Stub) vomsAdminGT4)._setProperty(GSIConstants.GSI_MODE, GSIConstants.GSI_MODE_NO_DELEG);
// set Context lifetime
((Stub) vomsAdminGT4)._setProperty(org.globus.wsrf.impl.security.authentication.Constants.CONTEXT_LIFETIME, 300);
 
try {
    // create a standard user in VOMS
    vomsAdminGT4.getPortType().createUser(user);
} catch (Exception e) {
    throw e;
}
 
try {
   // create a onLineCA user in VOMS
   vomsAdminGT4.getExtendedPortType().createOnlineCAUser(username, mail)
} catch (Exception e) {
   throw e;
}

Usage Examples from a Java client

User user = new User();
user.setDN(dn);
user.setCA(ca);
user.setCN(username);
user.setMail(email);
VOMSAdminImpl vomsAdmin = new VOMSAdminImpl("/path/to/vomsAPI.properties");
 
// create a standar user in VOMS
System.out.println("Create user with username: " + userName + ", mail: " + mail);
vomsAdmin.getPortType().createUser(user);	
 
// create a onLineCA user in VOMS
System.out.println("Create OnLineCA user with username: " + userName + ", mail: " + mail);
vomsAdmin.getExtendedPortType().createOnlineCAUser(userName, mail);

VOMS Attributes

VOMS Attributes interface is in charge to manage VOMS Generic Attributes. Generic attributes (GAs) are (name, value) pairs that that can be assigned to VO users and that end up in the Attribute Certificate issued by VOMS. GAs extend the range of attributes that VOMS can issue besides Fully Qualified Attributes Names (FQAN), i.e., allow VOMS to issue any kind of VO membership information that can be expressed as (name, value) pairs. Such information can then be leveraged by Grid applications to take authorization decisions. For their nature, GAs are issued to VO users. VOMS however provides a way to quickly assign GAs to all the VO members that belong to a specific VOMS group or that are assigned a specific VOMS role within a group. For this reason, you find GA management in user, group and role management pages in VOMS Admin. This interface allows to assign GA to users, by firstly creating the corresponding Generic Attribute class. This Generic Attribute class is used to define the name and possibly a description for the GA.

VOMS-Attributes sample usage

Here a sample usage of create, assign and list-user-attributes USER that lists the generic attributes defined for user USER.

VOMSAttributesAPI vomsAttributes = new VOMSAttributesAPI();      // it uses vomsAPI.properties configurations
// Create attribute with name and description
vomsAttributes.createAttributeClass(testName, testDescription);
 
// create a user
VOMSAdminImpl vomsAdmin = new VOMSAdminImpl();
User user = new User();
user.setCN(userName);
user.setDN(userName);
user.setCA(userCA);
user.setMail(mail);
vomsAdmin.getExtendedPortType().createUser(userName, DN, userCA, mail);
 
//Set attribute for user
vomsAttributes.setUserAttribute(user, attributeValue);
 
// List attributes for user
AttributeValue[] userAttributeValues = vomsAttributes.listUserAttributes(user);

CredentialsManagerImpl

This class provides a method to retrieve user's credentials. It manages communication with MyProxyCA server to generate simple credentials for the username provided and some operations are overloaded in order to simplify management of the users with a proxy certificate provided by gCube SimpleCA.

Usage Examples

//Retrieves ExtendedGSSCredential from MyProxy server with VOMS Attributes (roles, groups) attached
System.out.print("Retrieve Credentials from MyProxy with VOMS attributes:");
ExtendedGSSCredential cred;
try {
    cred = manager.getCredentials(userName, pwd, groupName);
    if (cred != null) {
	  byte[] data = cred.export(ExtendedGSSCredential.IMPEXP_OPAQUE);
	  File file = new File(proxyFile);
	  file.createNewFile();
	  FileOutputStream out = new FileOutputStream(proxyFile, false);
	  out.write(data);
	  out.close();
          System.out.println("Credentials for " + userName + " are correctly retrieved and stored in ");
          System.out.println("\t" + proxyFile + ".");
    }
} catch (Exception e) {
    e.printStackTrace();
}