Shibboleth v1.0 is stable and secure enough to deploy in production scenarios. While attempts have been made to include all functionality that would represent a break of interoperability with previous versions in v1.0, be aware that future versions of Shibboleth are likely to be developed and may include further implementation of the architectural document, functional enhancements, and user interface improvements.
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Please send any questions, concerns, or eventual confusion to firstname.lastname@example.org. This should include, but not be limited to, questions about the documentation, undocumented problems, installation or operational issues, and anything else that arises. Please ensure that you have the appropriate .tarball for your operating system.
Shibboleth is a system designed to exchange attributes across realms for the primary purpose of authorization. It provides a secure framework for one organization to transmit attributes about a web-browsing individual across security domains to another institution. In the primary usage case, when a user attempts to access a resource at a remote domain, the user's own home security domain can send certain information about that user to the target site in a trusted exchange. These attributes can then be used by the resource to help determine whether to grant the user access to the resource. The user may have the ability to decide whether to release specific attributes to certain sites by specifying personal Attribute Release Policies (ARP's), effectively preserving privacy while still granting access based on trusted information.
When a user first tries to access a resource protected by Shibboleth, they are redirected to a service which asks the user to specify the organization from which they want to authenticate. If the user has not yet locally authenticated to a WebISO service, the user will then be redirected to their home institution's authentication system. After the user authenticates, the Shibboleth components at the local institution will generate a temporary reference to the user, known as a handle, for the individual and send this to the target site. The target site can then use the handle to ask for attributes about this individual. Based on these attributes, the target can decide whether or not to grant access to the resource. The user may then be allowed to access the requested materials.
There are several controls on privacy in Shibboleth, and mechanisms are provided to allow users to determine exactly which information about them is released. A user's actual identity isn't necessary for many access control decisions, so privacy often is needlessly compromised. Instead, the resource often utilizes other attributes such as faculty member or member of a certain class. While these are commonly determined using the identity of the user, Shibboleth provides a way to mutually refer to the same principal without revealing that principal's identity. Because the user is initially known to the target site only by a randomly generated temporary handle, if sufficient, the target site might know no more about the user than that the user is a member of the origin organization. This handle should never be used to decide whether or not to grant access, and is intended only as a temporary reference for requesting attributes.
There are four primary components to the origin side in Shibboleth: the Attribute Authority (AA), the Handle Service (HS), the directory service, and the local sign-on system (SSO). The AA and HS are provided with Shibboleth, and an open-source WebISO solution Pubcookie can be obtained from www.pubcookie.org; the directory is provided by the origin site. Shibboleth is able to interface with a directory exporting an LDAP interface containing user attributes, and is designed such that programming interfaces to other repositories should be readily implemented. Shibboleth relies on standard web server mechanisms to trigger local authentication. A .htaccess file can be easily used to trigger either the local WebISO system or the web server's own Basic Auth mechanism, which will likely utilize an enterprise authentication system, such as Kerberos.
From the origin site's point of view, the first contact will be the redirection of a user to the handle service, which will then consult the SSO system to determine whether the user has already been authenticated. If not, then the browser user will be asked to authenticate, and then sent back to the target URL with a handle bundled in an attribute assertion. Next, a request from the Shibboleth Attribute Requester (SHAR) will arrive at the AA which will include the previously mentioned handle. The AA then consults the ARP's for the directory entry corresponding to the handle, queries the directory for these attributes, and releases to the SHAR all attributes the SHAR is entitled to know about that user.
There are three primary components to the target side in Shibboleth: the Shibboleth Indexical Reference Establisher (SHIRE), the Shibboleth Attribute Requester (SHAR), and the resource manager (RM). An implementation of each of these is included in the standard Shibboleth distribution. These components are intended to run on the same web server.
From the target's point of view, a browser will hit the RM with a request for a Shibboleth-protected resource. The RM then allows the SHIRE to step in, which will use the WAYF to acquire the name of a handle service to ask about the user. The handle service (HS) will then reply with a SAML authentication assertion containing a handle, which the SHIRE then hands off to the SHAR. The SHAR uses the handle and the supplied address of the corresponding attribute authority (AA) to request all attributes it is allowed to know about the handle. The SHAR performs some basic validation and analysis based on attribute acceptance policies (AAP's). These attributes are then handed off to the RM, which is responsible for using these attributes to decide whether to grant access.
The WAYF service can be either outsourced and operated by a federation or deployed as part of the SHIRE. It is responsible for allowing a user to associate themself with an institution of their specification, then redirecting the user to the known address for the handle service of that institution.
A Shibboleth federation provides part of the underlying trust required for function of the Shibboleth architecture. A federation is a group of organizations(universities, corporations, content providers, etc.) who agree to exchange attributes using the SAML/Shibboleth protocols and abide by a common set of policies and practices. In so doing, they must implicitly or explicitly agree to a common set of guidelines. Joining a federation is not explicitly necessary for operation of Shibboleth, but it dramatically expands the number of targets and origins that can interact without defining bilateral agreements between all these parties.
A federation can be created in a variety of formats and trust models, but must provide a certain set of services to federation members. It needs to supply a registry to process applications to the federation and distribute membership information to the origin and target sites. This must include distribution of the PKI components necessary for trust between origins and targets. There also needs to be a set of agreements and best practices defined by the federation governing the exchange, use, and population of attributes before and after transit, and there should be a way to find information on local authentication and authorization practices for federation members.
There are several essential elements that must be present in the environment to ensure Shibboleth functions well, both political and technical. Shibboleth is entirely written in Java on the origin side. These are the recommendations and requirements for a successful implementation of a Shibboleth origin.
A common institutional directory service should be operational; Shibboleth comes with LDAP capabilities built in, and the Attribute Authority has a Java API which will allow specification of interfaces with legacy directories. This is discussed further in section 4.d.
A method to authenticate browser users must be in place, preferably in the form of an enterprise authentication service. Some form of an SSO or a WebISO service is not explicitly necessary for Shibboleth; however, it is highly recommended. Implementation details of this are discussed in section 4.c.
Shibboleth is known to work on Linux and Solaris, but should function on any platform that has a Tomcat implementation.
It is recommended that a web server must be deployed that can host Java servlets and Tomcat, although not explicitly necessary, as Tomcat can still host an origin without it.
While it is not necessary for a target or origin to join a federation, doing so greatly facilitates the implementation of multilateral trust relationships. Each federation will have a different application process. When an origin is accepted into a federation, its information is added to the sites file used by the WAYF and target sites.
It may be necessary to join multiple federations depending on the sites with whom you wish to exchange attributes and the terms under which these interactions will take place. An origin site exists within the context of a single federation, while a single target may accept assertions issued by multiple federations if they are all recognized by the SHAR. If an organization wishes to be a member of multiple federations, it must run a separate origin site for each federation, including a separate AA and HS.
Attribute release and acceptance policies, the use and caching of attributes, and definition of commonly traded attributes are examples of specifications a federation may make. For more information on federations, please refer to the Deployer's Guide to Federations and the Shibboleth v1.0 architectural document.
Shibboleth's protocols and software have been extensively engineered to provide protection against many attacks. However, the most secure protocol can be compromised if it is placed in an insecure environment. To ensure Shibboleth is as secure as possible, there are several recommended security precautions which should be in place at local sites.
SSL use is optional for origin sites. Federation guidelines should be considered when determining whether to implement SSL, and, in general, SSL should be used for interactions with client machines to provide the necessary authentication and encryption to ensure protection from man-in-the-middle attacks. It is strongly suggested that all password traffic or similarly sensitive data should be SSL-protected. Assessment of the risk tradeoff against possible performance degradation should be performed for all applications.
Many other attacks can be made on the several redirection steps that Shibboleth takes to complete attribute transfer. The best protection against this is safeguarding the WAYF service and ensuring that rogue targets and origins are not used, generally by development of the trust model underneath Shibboleth. Shibboleth also leverages DNS for security, which is not uncommon, but attacks concerning bad domain information should be considered.
Information regarding origin users is generally provided by the authoritative enterprise directory, and the acceptance of requests from target applications can be carefully restricted to ensure that all requests the SHAR performs are authorized and all information the origin provides is accurate. Proper security measures should also be in place on directory access and population(see Access Control in the LDAP recipe for more information). Use of plaintext passwords is strongly advised against.
Server platforms should be properly secured, commensurate with the level that would be expected for a campus' other security services, and cookie stores on client machines should be well protected.
In the Shibboleth architecture, the SHIRE, SHAR, HS, and AA must all have various client and/or server certificates for use in signing assertions and creating SSL channels. These should be issued by a commonly accepted CA, which may be stipulated by some Federation rules. Different federations may require the use of different CA's.
The Attribute Authority maintains a set of policies called Attribute Release Policies (or ARP's) that govern the sharing of user attributes with Shibboleth target sites. When a user attempts to access a Shibboleth-protected resource, that resource's SHAR queries the user's AA for all attributes to which it is entitled. The SHAR provides its own name and the URL of the resource on behalf of which it is making the request. The AA finds the attributes associated with the browser user, determines an "Effective ARP" for this user, and then sends to the SHAR only the attributes/values allowed in this policy.
An ARP may be thought of as a sort of filter for outbound attributes; it cannot create attributes or data that aren't originally present, but it can limit the attributes released and the values those attributes may have when released. It does not change the information in the data sources in any way.
Each ARP is comprised of one or more rules that specify which attributes and values may be released to a target or set of targets. The assignment of rules to various targets is quite flexible and includes mechanisms for specifying: that a rule should affect all targets (default rule), exact SHAR names for which a rule is applicable, regular expressions against which SHAR names should be matched to determine if a rule is applicable, URL trees for which a rule is applicable.
For each request, an Effective ARP is determined by locating all ARP's applicable to the designated user and extracting each rule that matches the querying SHAR and resource. Attributes and values that are specified for release are included in the effective ARP, while those specified for denial are blocked from release. See section 5.a.i for details on how ARP's are processed.
Various ARP's may be combined in forming the Effective ARP. For instance, the Site ARP is administratively maintained and applies to all users for which the AA is answerable. User ARP's apply to a specific user only, and can be maintained either administratively or by the users themselves. All ARP's are specified using the same syntax and semantics.
Since Shibboleth deals both with daily technical and operational issues and also with contractual issues, a set of contacts should be set up to support the user base and to facilitate interactions with other Shibboleth sites and federation members. It is recommended that at least technical and administrative contacts be designated.
NTP should be run on all web servers. Shibboleth employs a short handle issuance time to protect against replay attacks. Because of this, any significant degree of clock skew can hinder the ability of users to access sites successfully.
Especially for higher education, there are a handful of laws enacted which may have important ramifications on the disclosure of personal information and attributes. Since Shibboleth does not necessarily need to transmit identity, it is an ideal solution for many higher education situations. Nevertheless, all parties within the United States of America are strongly advised to consult the Family Educational Rights and Privacy Act of 1974(FERPA), and all other relevant state and federal legislation before deploying Shibboleth.
The following requirements are primarily recommendations based on the most common ways to run Shibboleth. However, the origin should be able to run under any servlet container supporting Servlet API v2.3 and JSP specification 1.2.
- Apache 1.3.26+ (<2.0)
- Tomcat 4.1.18-24 LE Java server
- Sun J2SE v 1.4.1_01 SDK
Other versions of the JRE are not supported and are known to cause errors when working with certificates.
You may need to build mod_jk against Apache, which will generally require GCC or a platform-specific C compiler.
- An enterprise authentication mechanism
Ideally, this will be a WebISO or SSO system such as Pubcookie. The minimal requirement is for the web server to be able to authenticate browser users and supply their identity to the Handle Server.
- An enterprise directory service
Shibboleth currently supports retrieving user attribute information from an LDAP directory. For testing purposes, Shibboleth also supports a minimal echo responder which will always return two pre-defined attributes.
Ensure you have already obtained the proper .tarball.
The archive will expand into a shibboleth-origin-1.0/ directory(/usr/local/ recommended).
Run the following command to move the Java files into Tomcat's tree:cp /usr/local/shibboleth-origin-1.0/dist/shibboleth.war /usr/local/tomcat/webapps/
Tomcat 4.1.x requires that several Java jarfiles used by Shibboleth be located in a special "endorsed" folder to override obsolete classes that Sun includes with their JVM. To deal with this problem use the following command, adjusting paths as needed:$ cp /usr/local/shibboleth-origin-1.0/endorsed/*.jar /usr/local/tomcat/common/endorsed
Different versions of Tomcat or other Java servers may have other locations in which to place these files or deal with this problem. Refer to your application server's documentation to find out how to properly endorse classes, if necessary.
Restart Tomcat, which will automatically detect that there has been a new .war file added. This file will by default be expanded into /usr/local/tomcat/webapps/shibboleth.
Apache must be told to map the URL's for the Shibboleth HS and AA to Tomcat. Two popular ways of doing this are to include the following text directly in httpd.conf, or to place Include conf/mod_jk.conf in httpd.conf, and place the following lines in /etc/httpd/conf/mod_jk.conf:--------- begin ---------
LoadModule jk_module libexec/mod_jk.so
JkMount /shibboleth/* ajp13
--------- end ---------
Tomcat's /conf/server.xml ships by default with the Coyote/JK2 connector enabled, which fails with Shibboleth due to the lack of support for REMOTE_USER. This connector must be commented out. Then, uncomment and modify the traditional AJP 1.3 connector as follows:
Add address="127.0.0.1" inside the <Ajp13Connector> configuration element to prevent off-host access.
Add tomcatAuthentication="false" to the <Ajp13Connector> configuration element to ensure that the user's identity is passed from Apache to the servlet environment.
The main configuration file for Shibboleth's origin side is located in /webapps/shibboleth/WEB-INF/classes/conf/origin.properties.. This file contains configuration information for the origin side in several sections. The configuration must be consistent with values elsewhere in the deployment, such as the HS' certificate and with directory access bindings, etc., or access errors may occur.
All pathnames are relative, and have an effective root path of $TOMCAT_HOME/webapps/shibboleth/WEB-INF/classes/. To specify files outside of the webapp, specify a full URI, such as file:///usr/local/shibboleth/.
Fields that are purple are optional; grey fields are mandatory.
These are the variables that may be specified for each component of origin.properties:
- edu.internet2.middleware.shibboleth.hs.HandleServlet.issuer = <domain name>
Specifies the DNS name the HS should use for itself in issuing assertions.
- edu.internet2.middleware.shibboleth.hs.HandleServlet.siteName = <URI>
Specifies the the URI to use as the name of the origin site as a whole. This field is primarily meant to be populated in the context of the federation in which the origin site resides, is intended to be globally unique, and will typically be assigned by the federation.
- edu.internet2.middleware.shibboleth.hs.HandleServlet.AAUrl = <url>
Specifies the URL at which the HS' corresponding AA may be contacted.
- edu.internet2.middleware.shibboleth.hs.HandleServlet.username = <var>
Specifies the HTTP request header that should be used to acquire the user's principal name from the authentication service. Defaults to REMOTE_USER.
- edu.internet2.middleware.shibboleth.hs.HandleServlet.authMethod = <uri>
Specifes the URI used to populate AuthenticationMethod in the SAML attribute assertion. This corresponds to the method used to authenticate users by the authentication service used by the HS. Some common authentication methods and corresponding URI's are listed below; for a complete list, please consult section 7.1 of the SAML 1.1 core specifications or your federation's guidelines.
urn:oasis:names:tc:SAML:1.0:am:password The authentication was performed using a password. urn:ietf:rfc:1510 The authentication was performed using Kerberos. urn:oasis:names:tc:SAML:1.0:am:X509-PKI The authentication was performed using a certificate and key issued to the end user. More specific forms of PKI authentication such as SPKI and XKMS are also assigned URN's in the SAML specs.
- edu.internet2.middleware.shibboleth.hs.HandleServlet.keyStorePath = <pathname>
Specifies the location of the Java keystore containing the x.509 certificate and matching private key to be used by the HS.
- edu.internet2.middleware.shibboleth.hs.HandleServlet.keyStorePassword = <password>
Specifies the password to the referenced keystore.
- edu.internet2.middleware.shibboleth.hs.HandleServlet.keyStoreKeyAlias = <alias>
Specifies the alias used for accessing the private key.
- edu.internet2.middleware.shibboleth.hs.HandleServlet.keyStoreKeyPassword = <password>
Specifies the password used to retrieve the private key.
- edu.internet2.middleware.shibboleth.hs.HandleServlet.certAlias = <alias>
Specifies the alias for the certificate corresponding to the private key used by the HS. Defaults to the private key's alias.
General AA Configuration:
- edu.internet2.middleware.shibboleth.aa.AAServlet.authorityName = <domain name>
Specifies the name of the AA, which is typically the domain name of the server running it.
- edu.internet2.middleware.shibboleth.aa.AAServlet.passThruErrors = <true/false>
Specifies whether the AA should pass on internal errors to the SHAR for debugging purposes. Defaults to false.
AA Attribute Resolution:
- edu.internet2.middleware.shibboleth.aa.attrresolv.AttributeResolver.ResolverConfig = <pathname>
Specifies the location of the configuration file for the resolver the AA uses to build attributes. Defaults to /conf/resolver.xml. For information on how to configure and use the attribute resolver, consult section 4.e.
- edu.internet2.middleware.shibboleth.aa.arp.ArpRepository.implementation = <string>
References the type of ARP repository implemented. Shibboleth provides a built-in ARP repository specified by edu.internet2.middleware.shibboleth.aa.arp. provider.FileSystemArpRepository.
Note that the set of principals that an ARP applies to is not expressed by the ARP itself, but rather the implementation of the ARP repository. For example, if the ARP repository were implemented in LDAP, the ARP's that apply to a user would be attributes of that user's personal LDAP entry, and the site ARP would be an attribute of an entry representing the site. While not performed by the built-in ARP repository, a repository implementation might also implement group ARP's; for example, in an LDAP directory, the user entry might have some group membership attributes that refer to group entries, and those group entries would have ARP attributes, and all those ARP's would be applicable.
- edu.internet2.middleware.shibboleth.aa.arp.provider.FileSystemArpRepository.Path = <pathname>
Specifies the relative or absolute path to the folder containing the ARP files.
- edu.internet2.middleware.shibboleth.aa.arp.provider.FileSystemArpRepository.ArpTTL = <seconds>
Specifies the duration in seconds that ARP's may be cached by the AA. Defaults to 0, or no caching.
Handle Repository Configuration:
- edu.internet2.middleware.shibboleth.hs.HandleRepository.implementation = <string>
Specifies the method by which the HS and AA share handles. These are by default passed by memory(which can be specified explicitly using edu.internet2.middleware.shibboleth.hs.provider. MemoryHandleRepository), and may also be passed using symmetric encryption with edu.internet2.middleware.shibboleth.hs.provider.CryptoHandleRepository.
edu.internet2.middleware.shibboleth.hs.provider. MemoryHandleRepository (specify if edu.internet2.middleware.shibboleth.hs.HandleRepository. implementation is MemoryHandleRepository)
- edu.internet2.middleware.shibboleth.hs.BaseHandleRepository.handleTTL = <seconds>
Specifies the time in seconds for which issued handles are valid. Defaults to 1800, or 30 minutes. The time should be long enough to allow for clock skew and short enough to protect against various attacks. Consult your federation guidelines for further advice.
edu.internet2.middleware.shibboleth.hs.provider.CryptoHandleRepository (specify if edu.internet2.middleware.shibboleth.hs.HandleRepository. implementation is CryptoHandleRepository)
In order to use the crypto repository implementation, you must have a DESede secret key in a keystore of type JCEKS. The origin distribution includes a program that will automatically generate such a key. In order to invoke it, run ./ant genSecret, which will create a keystore in $SHIB_HOME/src/conf/handle.jks that includes the key, with an alias of handleKey and a password of shibhs. If ./ant dist is run subsequently, this keystore will be included in the webapp archive that is created.
- edu.internet2.middleware.shibboleth.hs.provider.CryptoHandleRepository.keyStorePath = <pathname>
Specifies the path to the keystore containing the key used to encrypt passed principal identifiers.
- edu.internet2.middleware.shibboleth.hs.provider.CryptoHandleRepository.keyStorePassword = <password>
Specifies the password for the keystore.
- edu.internet2.middleware.shibboleth.hs.provider.CryptoHandleRepository.keyStoreKeyAlias = <password>
Specifies the alias for the appropriate encryption key within the keystore.
- edu.internet2.middleware.shibboleth.hs.provider.CryptoHandleRepository.keyStoreKeyPassword = <password>
Specifies the password used to retrieve the key.
- edu.internet2.middleware.shibboleth.hs.CryptoHandleRepository.handleTTL = <seconds>
Specifies the time in seconds for which issued handles are valid. Defaults to 1800, or 30 minutes. The time should be long enough to allow for clock skew and short enough to protect against various attacks. Consult your federation guidelines for further advice.
- edu.internet2.middleware.shibboleth.audiences = <URI's>
Specifies a list of URI's that will be used for the Audience field of the SAML attribute assertion. All URI's listed will be sent with any assertion issued by the AA. These URI's are defined and provided by and correspond to federations.
Note that the values of the URI's here must match one of the policy URI's accepted by the receiving target in the [policies] section of shibboleth.ini or interoperation will fail by design.
The SAML messages generated by the HS must be digitally signed. Each HS must be issued a private and public keypair, which is stored in a Java keystore. The current implementation of Shibboleth requires the use of an ordinary file-based keystore. The keytool program is included with the Java development and runtime kits. Access parameters to the keystore will need to be consistent with those specified in origin.properties.
A sample keystore is included in the distribution and can be found in /usr/local/tomcat/webapps/shibboleth/WEB-INF/classes/conf/keystore .jks with a password of shibhs. It is intended to serve as an example and not as a production keystore.
The following commands will generate a new RSA keypair and store it in the keystore.jks file, with a keyentry alias of hs and new passwords of your choosing:$ cd /usr/local/tomcat/webapps/shibboleth/WEB-INF/classes/conf
$ keytool -storepasswd -keystore keystore.jks -new <newpassword>
$ keytool -genkey -keystore keystore.jks -alias hs -keyalg rsa -keysize 2048
You will be prompted for passwords during key generation as needed, to access the keystore and assign the key itself its own password. You will also be prompted for the distinguished name components to associate with the key. This DN will be placed in a self-signed certificate and will be the name that is associated with your HS by Shibboleth. In particular, the first component you enter for Name will be the Common Name(when keytool asks for first and last name, common name is intended), which in most cases should be the hostname of the HS system. Note that a specific federation of sites may dictate what type of key algorithm, key size, or validity period is appropriate.
Once you have a keypair generated, the self-signed certificate must be replaced with a certificate signed by a CA acceptable to the federation you will be joining. Shibboleth is generally able to climb trust chains to reach an intermediate CA's root CA. Note that the intermediate CA's signing certificate must still be signed by a root CA recognized by the federation.
To generate a certificate signing request for a CA, use the following command:$ keytool -certreq -keystore keystore.jks -alias hs -file <csr-file>
The contents of <csr-file> can then be sent to a CA for signing. You will receive a signed certificate in return in a file. To install the new certificate into your keystore, use the following command:$ keytool -import -keystore keystore.jks -alias hs -file <cert-file>
Note that if the signing CA's certificate is not already installed in your keystore as a trusted signer, you may need to download the CA's root certificate and import it into the keystore file under a different alias, using a command similar to the above.
For information on sharing certificate/key pairs between Apache and Java keystores see section 5.b..
The interaction between the HS and the local authentication system is implemented by supplying the HS with the identity of the browser user. Most often, this will mean protecting the HS servlet with some form of local authentication that populates REMOTE_USER. Location blocks can be added to httpd.conf, associating the appropriate authentication mechanism with the URL of the HS servlet. The following example demonstrates association of a very basic authentication method with the HS:<Location /shibboleth/HS>
AuthName "Internet2 Handle Service"
Note that .htaccess files cannot be used for this purpose because URL's are "virtualized" by Tomcat.
It is recommended that the origin be tested at the end of this process using the process described in section 6.a.
Shibboleth supports client certificate authentication by utilization of a filter that relies on the web server to do all processing to ensure that the certificate is both valid and appropriate for the application. An example deployment descriptor is included with the Shibboleth distribution at $SHIB_HOME/webAppConfig/origin-client-cert.xml. To enable the filter, add the following to the deployment descriptor (web.xml):<filter>
Client Cert AuthN Filter
Client Cert AuthN Filter
By default, the filter pulls the principal name out of the CN of the cert's Subject by using regular expression grouping. This may be done using patterns such as:regex: '.*CN=([^,/]+).*' match group: 1
The servlet filter will accept two initialization parameters, regex and matchGroup that can be used to extract the principal name differently.
For a more basic introduction to ARP's, please refer to section 2.e.
An ARP determines which attributes are released to a SHAR when a user tries to access a resource. It acts as a sort of filter on user information contained in the authoritative directory, deciding what can be released to whom, but not modifying or creating information itself. ARP's are generally administered by the site, but Shibboleth will provide for users to broker control of their own information and privacy by allowing them to create ARP's pertaining to themselves.
It is recommended that a set of policies be established between an origin and frequently accessed targets to specify default releases of expected attributes. Federation guidelines may provide more information on population of ARP's.
Currently, there is no direct mechanism for users to create their own ARP's besides direct XML writing. In future versions, a GUI will be provided for simpler management of ARP's. Care should be given to balancing giving sufficient control over information to users and avoiding access problems. For example, users may decide to restrict the release of their personal information to such a degree that access to a site for a class may become impossible because Shibboleth cannot release enough information to grant access.
The Shibboleth distribution contains an example site arp that releases the eduPersonScopedAffiliation attribute to all targets. For more precise information regarding how ARP's are processed or syntactically formed, please refer to section 5.a.i.
The resolver.xml file controls the retrieval of attributes from enterprise repositories, and the process of mapping them to Shibboleth/SAML attributes. For more precise information regarding how attributes are processed or syntactically formed, please refer to section 5.c.
In order to make the Shibboleth software operational, however, minor edits must be made to the example version of the resolver.xml file. The file can be found at /webapps/shibboleth/WEB-INF/classes/conf/resolver.xml. Two changes are necessary:
1. The value of the smartScope attribute should be changed to the Domain Name value submitted to the Federation. It appears on two SimpleAttributeDefinition elements: eduPersonScopedAffiliation and eduPersonPrincipalName.
2. The comment indicators should be removed from around the definitions of those two elements ( <!-- and --> ).
This section applies primarily to the syntactic and technical details of ARP's. For basic information on and explanation of what an ARP is and how it should be managed, please refer to sections 2.e and 4.d.
Every ARP file contains one ARP. ARP's may be specified either as the site ARP or user ARP's. The site ARP pertains to every principal for whom the AA retrieves information; a user ARP applies only to the individual user for whom it is defined. The set of principals to whom the ARP applies is defined by the name of the ARP file: the site ARP is stored in arp.site.xml and user ARP's are stored as arp.user.$PRINCIPALNAME.xml. Up to two ARP's will apply to a principal: the site ARP, and the user ARP for that principal.
Each ARP acts as a container that holds a set of ARP rules that are applicable to the principals that ARP is effective for. Each ARP rule specifies a single release policy within the ARP container pertaining to a specific set of targets. This set of targets may be specified as a specific SHAR, a SHAR tree, or a regular expression, and becomes the ARP rule's target definition. Each ARP rule may contain specifications regarding the release of any number of attribute values to requests matching that ARP rule for that user. ARP rules may be flagged as default, implying that they are always applied to any user matched by the ARP container. Note that ARP's may also be used to restrict specific attribute/value pairs in addition to restricting or releasing individual attributes.
When a query is received, the AA generates an effective ARP, which is the fully evaluated set of ARP rules regarding that SHAR based on all ARP containers applicable to the principal. This effective ARP is then applied to attribute values retrieved from the directory and the appropriate assertion is constructed. Default rules are always included in construction of the effective ARP.
When a request arrives from a particular SHAR, the applicable set of ARP rules are parsed into an effective ARP. This parsing is done as follows:
- Identify all ARP's that should be applied to a particular principal. This is done by isolating the files in the folder specified by edu.internet2.middleware.shibboleth.aa.arp.provider.FileSystemArpRepository.Path that have the name either arp.site.xml or arp.user.$PRINCIPALNAME.xml.
- Find all ARP rules relevant to the query:
- Any ARP rules within the identified ARP's designated as defaults are automatically included in the effective ARP without performing any matching functions.
- For each non-default rule in each identified ARP, the matching functions specified in the rule's target definition are performed. A separate matching function is performed for the requesting SHAR and the resource on behalf of which the SHAR is making the request.
- Each matching function evaluates to TRUE if the match is successful or FALSE if it is unsuccessful. If both functions evaluate to TRUE, the rule is included in the Effective ARP.
- Construct the Attribute Filter:
- For each attribute, compile a temporary list of associated rules that includes all values with a release qualifier of permit.
- Subtract from this list all attribute values with rules specifying a release qualifier of deny. The resulting list represents the allowable release values for the attribute and is used as a mask for the values which are returned from the Attribute Resolver.
- If a statement specifies that all values should be permitted, then specific deny qualifiers for specific values should still be enforced. If a statement specifies that all values should be denied, then permit qualifiers for specific values will be ignored.
- Using the mask and attributes returned from the Attribute Resolver, an assertion is constructed.
Each ARP is described by an XML file based on a standard .xsd schema. It consists of a standard AttributeReleasePolicy element referencing the appropriate xsi:schemaLocation and a self-explanatory Description element followed by any number of Rule elements. Each Rule element must consist of a Target element and one or more Attribute elements. The Target element specifies the rules by which the target definition is formed. The Attribute elements specifies the name and values of the attributes that may be released.
The simplest possible ARP is as follows, which releases eduPersonScopedAffiliation to any target for the users the ARP applies to:<?xml version="1.0"?>
<AttributeReleasePolicy xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="urn:mace:shibboleth:arp:1.0" xsi:schemaLocation="urn:mace:shibboleth:arp:1.0 shibboleth-arp-1.0.xsd">
<Description>Simplest possible ARP.</Description>
<AnyValue release= "permit"/>
All ARP's must take the same basic form. A detailed description of how each element of the Rule element may be sub-populated follows:
The Target element:
Target may contain either the AnyTarget element, which will cause the Target to always return TRUE, or both the Requester element, which provides for matches to be performed against the SHAR name and the Resource element, which provides for matches to be performed against the requested URL.
There are three matches that may be performed by the AA in evaluating ARP's by using the matchFunction component of the Requester and Resource elements. The following match patterns may be specified directly following the Requester or Resource elements, such as <Requester matchFunction="urn:mace:shibboleth:arp:matchFunction:regexMatch">:
May be used with the Requester element.
Evaluates to TRUE when the string content of the Requester element matches exactly the name of the requesting SHAR. Otherwise evaluates to FALSE. Serves as the default value associated with Requester if none is specified.
May be used with the Resource element.
Evaluates to TRUE when the location of the resource either matches exactly or begins with the string content of the Resource element. Otherwise evaluates to FALSE.
May be used with both the Requester and Resource elements.
Evaluates to TRUE when the name of the requesting SHAR or the requested URL tree is a valid match of the regular expression represented as the content of the containing element. Otherwise evaluates to FALSE. Regular expressions are evaluated in accordance with the the Java 1.4 Pattern API.
The Attribute element:
The Attribute element must always specify the URN of the attribute whose release parameters it specifies. Additionally, it must contain either the AnyValue element or one or more Value elements. These elements, in turn, must specify either release = permit or deny. The Value element must then contain one value for which the rule applies. Examples:<Attribute name="urn:mace:dir:attribute-def:eduPersonPrincipalName">
Permits the release of eduPersonPrincipalName with any value.<Attribute name="urn:mace:dir:attribute-def:eduPersonScopedAffiliation">
Denies the release of eduPersonScopedAffiliation value email@example.com. Other values of the attribute may still be released if so specified by a permit ARP.
The JDK includes the command line program keytool for managing Java keystores. This utility cannot import or export private key information, making it difficult to use the same private key and certificate for Apache and Java-based applications. The Shibboleth distribution includes extkeytool, a program that can be used in conjunction with keytool to perform these tasks. Select the appropriate step-by-step procedure for your situation from the following guides.
Before running extkeytool, the variable SHIB_HOME must be set to the path to the directory where the Shibboleth tarball was exploded(typically /usr/local/shibboleth-origin-1.0/).
If you have a pre-exiting RSA key/certificate combination in a keystore and you would like to use it with Apache:
Determine the alias of the keystore keyEntry containing the key you would like to use in your Apache setup. Assuming that your keystore is named yourstore, the following command should present a list of the entries in the keystore.
$ keytool -list -v -keystore yourstore
Assuming that you identified the appropriate alias as youralias and the password for the keystore is yourpass, enter the following command to export the key in Base64-encoded pkcs8 format.
$ extkeytool -exportkey -keystore yourstore -alias youralias -storepass yourpass -rfc -file yourkey.pkcs8
In order to use this key with Apache, you must convert it to PEM-encoded RSA native format. You have the option of storing the key unencrypted or encrypted:
To use the unencrypted format, enter the following command for the conversion:
$ openssl pkcs8 -in yourkey.pkcs8 -nocrypt|openssl rsa -out yourkey.key
To use the encrypted format, enter the following command for the conversion:
$ openssl pkcs8 -in yourkey.pkcs8 -nocrypt|openssl rsa -des3 -out yourkey.enckey
The following command will export the corresponding certificate.
$ keytool -export -keystore yourstore -alias youralias -rfc -file yourcert
Set the mod_ssl SSLCertificateKeyFile and SSLCertificateFile directives to point to the two files you have just created. Take care to remove any temporary files you created (i.e. yourkey.pkcs8) and set appropriate file permissions, especially if you chose to store the key in an unencrypted format.
If you have a pre-existing RSA key/certificate combination that you use with Apache and would like to import it into a java keystore:
Convert the private key to unencrypted DER-encoded pkcs8 format. Assuming your PEM-encoded key is stored in a file named yourkey.enckey, enter the following command.
$ openssl pkcs8 -in yourkey.enckey -topk8 -nocrypt -outform DER -out yourkey.der.pkcs8
Create a certificate bundle file. This file should include a series of PEM-encoded X509 certificates representing a complete trust chain, from the root CA certificate to the certificate that matches your private key. If your certificate is stored in a file named mycert and the CA signer certificate is stored in a file named ca.cert, you might enter the following command to create the bundle.Note: mod_ssl-enabled Apache installations include a number of commonly recognized CA certificates in the ca-bundle.crt file under the $ServerRoot/conf/ssl.crt/ directory.
$ cat mycert ca.cert > cert.bundle
Import the key and certificate into the keystore. Assuming you have already created a keystore named yourstore with a password of of yourpass, enter the following command to store the data under the alias youralias.
$ ./extkeytool -importkey -keystore yourstore -alias youralias -storepass yourpass -keyfile yourkey.der.pkcs8 -certfile cert.bundle -provider org.bouncycastle.jce.provider.BouncyCastleProvider
You can verify that the import was successful by listing entry. Use the command below.
$ keytool -list -v -keystore yourstore -alias youralias
Remember to delete yourkey.der.pkcs8, as it contains your unencrypted private key.
If you are starting from scratch and do not yet have a certificate/key pair:
Generate an RSA private key. Use the command below, substituting yourkey with an appropriate name to use to refer to the key.
$ openssl genrsa -des3 -out yourkey.enckey 1024
The following command generates a Certificate Signing Request, which should be communicated to a Certificate Authority.
$ openssl req -new -key yourkey.enckey
The Certificate Authority should respond with a PEM-encoded X509 certificate. Set the mod_ssl SSLCertificateKeyFile directive to point to the key file you just created and the SSLCertificateFile directive to point to file containing the certificate issued by the Certificate Authority. Previous sections explaion how to share the key/certificate pair with a Java keystore.
Shibboleth provides a powerful attribute resolver that allows origins to quickly configure the retrieval of simple attributes from standard types of attribute stores. The resolver is configured using an xml file wich should be pointed to with the edu.internet2.middleware.shibboleth.aa. attrresolv.AttributeResolver.ResolverConfig propety in origin.properties as described in section 4.a. For more complex attributes or those that require processing before release, customized Java classes will need to be written. For more information, consult the programmer's guide.
The resolver is essentially a directed graph from attribute definitions to data connectors. The data connectors pull data, in the form of attributes, from external data sources. The attribute definitions then process this data into a from suitable for use by Shibboleth. This procedure can be as simple as taking an unmodified string value from a data connector and tagging it with a name or can include arbitrarily complex business rules.
The resolver.xml file that is pointed to by origin.properties consists of zero or more attribute definitions followed by zero or more data connectors. Each attribute definition consists of an identifier corresponding to the URN of the attribute, and optional references to data connectors on which it depends. Each data connector consists of a string identifier which is used by attribute definitions that refer to it, and one or more elements specific to the configuration of that data connector.
Shibboleth comes with two attribute definitions provided in version 1.0: the SimpleAttributeDefinition, which acts as a basic proxy for attributes supplied by data connectors with some name conversion and attribute scoping added, and a CustomAttributeDefinition, which can be used to configure user-created attribute definition plugins. Similarly, Shibboleth 1.0 comes with two data connectors: the JNDIDirectoryDataConnector, which pulls data from any source for which there is a JNDI Directory Context implementation, including LDAP, NDS, etc., and the CustomDataConnector, which is used to configure user-created data connector plugins.
A detailed explanation of each configuration option for the provided connectors follows:
- id = <string>
Specifies a unique, textual name for the connector used by attribute definitions to refer to and use it to build attributes. Contained within the JNDIDirectoryDataConnector element.
- <Property name="<name>" value="<value>"/>
An element of the element JNDIDirectoryDataConnector. Specifies a set of name/value pairs that are used to configure the JNDI Directory Context. This list of name/value pairs is defined by the context itself, but is specified within resolver.xml. Refer to the Shibboleth CVS for an example of names and values used to connect to an LDAP directory.
An element of the element JNDIDirectoryDataConnector. This element defines the DN filter used to perform the LDAP search. The search string must return no more than one result.
An element of the element Search. This element grants some fine-grained control over the LDAP API calls.
- <cacheTime "<seconds>"/>
An element of the element JNDIDirectoryDataConnector. Specifies an optional duration in seconds for which the attribute resolver may cache information retrieved from this connector.
A representation of a properly constructed JNDIDirectoryDataConnector element would look like:<JNDIDirectoryDataConnector id="directory">
<Controls searchScope="SUBTREE_SCOPE" returningObjects="false" />
<Property name="java.naming.factory.initial" value="com.sun.jndi.ldap.LdapCtxFactory" />
- id = <string>
Specifies a unique, textual name for the attribute which is used as the attribute's name when it is sent over the wire by Shibboleth. Contained within the SimpleAttributeDefinition element.
- <AttributeDependency / DataConnectorDependency requires="<id>"/>
An element of the element SimpleAttributeDefinition, which may contain 0 or more of either AttributeDependency or DataConnectorDependency. These specify attributes and data connectors that can be utilized by this attribute definition. Each of these elements must contain a requires statement which this attribute definition can then use to build its value.
- smartScope = "<domain>"
Specifes a domain scope to be attached to the attribute. If the value of the attribute as retrieved from the data connector includes a pre-existing scope (firstname.lastname@example.org), that scope is used instead. Contained within the SimpleAttributeDefinition element.
- sourceName = "<string>"
Specifies a different source attribute name to be used in calls to the data connector, while the name on the wire will be the specified id. This would be useful to send a local UniversityID attribute as eduPersonPrincipalName. If not supplied, the connector tokenizes the id field and uses the section following the # to query data connectors. Contained within the SimpleAttributeDefinition element.
- <cacheTime "<seconds>"/>
An element of the element SimpleAttributeDefinition. Specifies an optional duration in seconds for which the attribute resolver may cache this attribute for use in additional assertions.
- <lifeTime "<seconds>"/>
An element of the element SimpleAttributeDefinition. Specifies in the attribute assertion how long the attribute should be cached and retained by the target upon receipt. Federations and trust agreements may have some bearing on the population and use of this field.
A representation of a properly constructed SimpleAttributeDefinition element would look like:<SimpleAttributeDefinition id="urn:mace:dir:attribute-def:eduPersonPrincipalName" smartScope="shibdev.edu" sourceName="universityPerson">
A properly formed resolver.xml file to automatically generate a simple response for EPPN may take the form:<AttributeResolver xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="urn:mace:shibboleth:resolver:1.0" xsi:schemaLocation="urn:mace:shibboleth:resolver:1.0 shibboleth-resolver-1.0.xsd">
<SimpleAttributeDefinition id="urn:mace:dir:attribute-def:eduPersonPrincipalName" smartScope="shibdev.edu">
<CustomDataConnector id="echo" class="edu.internet2.middleware.shibboleth.aa.attrresolv.provider.SampleConnector" />
There are additional examples of resolver.xml files provided in the Shibboleth CVS.
Origin sites are encouraged to provide federations with the URL of a local Shibboleth error page. If a browser user from the origin site encounters a problem at a shibbolized target, the target is likely to display an error page that includes a link back to this origin provided page.
The page should provide information on how to obtain local support for using Shibbolized resources. It might also include suggestions on what information should be recorded before beginning the problem resolution process.
This section provides basic information about testing, logging, and error handling for Shibboleth origins. This information is not intended to be comprehensive, but instead rudimentary guidelines for basic configuration tests and problems. For more detailed information or answers to specific problems not addressed in this section, please mail email@example.com with a thorough description of errors and configurations used.
Internet2 provides a basic target that can be used to test origin setup functionality. After your origin is recognized by InQueue, simply use any browser to access https://wayf.internet2.edu/InQueue/sample.jsp. Select your origin's name and follow the login process as a user would. Note that SSL must be used, and both the HS and AA must be fully configured.
The test target will then display a simple page which includes the basic information sent to it by your origin and the authentication rules it is using.
For information regarding specific error messages that may be generated if the origin does not work successfully, please refer to section 6.c.
Shibboleth's origin components log various operations which may prove useful for auditing, testing, and security purposes. This data is sent through log4j's standard mechanism. The location of the log file, the level at which the log is output, the formatting of the logs, and many more options may be configured by editing /WEB-INF/classes/conf/log4j.properties. By default, it is setup to log to the console of the servlet container, with a level of WARN, but there is also a commented out example in the file to give a possible alternate configuration.
A knowledge base is being developed in the Shibboleth Deployer's FAQ. Please mail mace-shib-users@ internet2.edu with any additional questions or problems encountered that are not answered by this basic guide.