ApplicationDefaults

Overview

The <ApplicationDefaults> element defines most of the runtime behavior of the software when it comes to SAML behavior and application session policy. In rare cases, this can be further broken down more granularly by nesting <ApplicationOverride> elements to override behavior for different virtual hosts, or in very ill-advised cases, different paths.

The usual pattern is to define most of this information once, in the outer element. Most of the things you might want to override can be handled more elegantly without explicit use of the <ApplicationOverride> feature.

You should not use overrides to segregate traffic from different IdPs; that's an anti-pattern. The set of IdPs you trust should be a global consideration and you should authorize individual access based on the attributes in the user's session.

Every request to the web server is associated with what the SP denotes an "application" by the request mapper component. An application represents distinct collections of resources within the server's document tree that share the same general configuration requirements, although access control can be enforced on a finer-grained basis.

Repeating: in most cases, all requests should be left to map to the "default" application represented by this outer element, but the majority of the SP's more advanced functionality can, if needs must, be defined on a per-application basis. Supported protocol endpoints and handlers, security policies, credentials for signing, encryption, and TLS, attribute extraction/resolution/filtering are just some of the options handled here. When a resource protected by the SP absolutely needs distinct behavior in these kinds of areas, a new application needs to be defined and referenced by the request mapper using the applicationId property.

Basic Configuration

The default configuration of the <ApplicationDefaults> element and most of its subelements will work in most circumstances with a few modifications:

The entityID attribute on the <ApplicationDefaults> element needs to be changed to the SAML entityID you'd like to use for your SP deployment. This must be the value your federations and partners are expecting and should be carefully chosen to be a permanent and representative URL denoting your service. It does not necessarily equate to the hostname(s) at which your service runs, particularly in cases where you may have a multiitude of virtual hosts for different customers. Do not create an entityID for each customer; that's an anti-pattern in general and also tends to work very poorly with a lot of federations that make common use of Shibboleth.

Configure SSO to an IdP or with a Discovery Service
- To use a specific IdP, change the entityID setting in the <SSO> element to match the value in that IdP's metadata.
- To use a discovery service (e.g. our EDS), remove the entityID setting in the <SSO> element, and set the discoveryProtocol and discoveryURL settings appropriately.
- While you can determine the IdP based on some property of the resource URL, this is generally a bad idea because even if your application is siloed to one organization at a time, that organization may choose to operate more than one IdP, and you should accomodate that by using a discovery mechanism of some kind.

The <CredentialResolver> element's content must point to the key and certificate pair(s) to use for decryption and signing (authenticating the SP to other systems). By default it matches the filenames used for the keypairs generated by the installation process.

Typically, each federation, or IdP partner if you're dealing with sites directly, will supply you with metadata describing itself. One <MetadataProvider> element needs to be added for every metadata source you'd like to point to, or you can combine them in one file yourself. Directly relying on remote sources of metadata from individual IdPs tends to be a risky and ill-advised idea and Shibboleth is geared around the use of a third party trust model whereby metadata for many IdPs is acquired at one time from a trusted source.

REMOTE_USER is a special server variable used to pass the primary identifier of a browser user. An attribute ID defined in the attribute-map.xml file can be designated as the source for REMOTE_USER. Multiple attributes may be listed in order of precedence.

Reference

Attributes

Most of these are optional, with the exception of the entityID setting.

Name Type Default Description

id string default If present, this must be set to the actual string "default"

entityID

URI

Required, this is the SP's entityID, the SAML identifier that uniquely names an SP. IdPs do not have visibility into any internal application boundaries of an SP deployment. Any external distinctions must be noted by assigning a different entityID, which can be done on a content-specific basis via the entityIDSelf content setting.

policyId

string

References a policy defined via a <SecurityPolicies> element. When omitted, the default policy is assumed.

requireAuthenticatedEncryption

boolean

false

When true, the SP will refuse to decrypt assertions that are unprotected by a signature or an authenticated transport (e.g., back-channel TLS) unless the data is encrypted with a special type of algorithm that includes built-in integrity protection to prevent chosen ciphertext attacks. At the present time, this will generally block use of encryption unless signed responses are enabled by an IdP.

homeURL URL "/" A location to send the browser to when a resource URL is required but cannot be determined (for example, following SSO when no location to use can be recovered). If this is omitted the SP will use the root of the applicable virtual host.

REMOTE_USER

whitespace-delimited list of strings

Specifies a list of attribute IDs to pull from in a session's cached attributes; the first one found with a value is set as REMOTE_USER

unsetHeaders

whitespace-delimited list of strings

Normally, the set of possible headers that might be used to carry attributes is determined by querying the configured attribute extractor(s). This allows the list to be overridden. Not typically used.

attributePrefix

string

Applies a fixed prefix to the IDs of any attributes stored in user sessions. Used for special situations such as passing environment variables across Tomcat's AJP connector protocol.

Do NOT set this to "HTTP_", as this causes IIS to treat server variables with this prefix as actual request headers, but without the necessary header smuggling prevention code enabled. This is vulnerable to security impersonation attacks.

metadataAttributePrefix

string

If set, attributes extracted from metadata have their IDs prefixed with this value. Allows applications to distinguish between attributes about the user and attributes about the user's identity provider in the odd case that they might overlap.

Relying Party Attributes

The following supported attributes are grouped because they can be overridden per-partner using a <RelyingParty> element:

authType

string

TLS

Specifies the transport-layer authentication mechanism that is used for back-channel SOAP messages to an IdP. The values permitted are implementation dependent, but may include:

`TLS`	client certificate TLS/SSL authentication
`basic`	HTTP Basic-Auth (cleartext name/password)
`digest`	HTTP Digest-Auth
`ntlm`	Microsoft's NTLM authentication
`gss`	GSS-API (SPNEGO)

authUsername string Required for non-TLS and GSS authType values, this is the username to use

authPassword string Required for non-TLS and GSS authType values, this is the password to use

signing

Controls outbound signing of XML messages. See the Signing and Encryption topic.

signingAlg

URI

specifier for RSA-SHA256

An XML Signature signature algorithm specifier for signatures produced by the SP

digestAlg

URI

specifier for SHA256

An XML Signature digest algorithm specifier for signatures produced by the SP

encryption

Controls outbound encryption of XML messages and content. See the Signing and Encryption topic.

encryptionAlg

URI

specifier for RSA-OAEP-SHA1

An XML Encryption key wrap/transport algorithm specifier for encryption performed by the SP. The actual symmetric encryption algorithm will be derived from it.

cipherSuites

OpenSSL cipher expression

see description

Directly configures the TLS ciphers to support when making SOAP connections. The default value (ALL:!aNULL:!LOW:!EXPORT:!RC4:!SSLv2) is historical and has been in place for a few releases, and has been left alone to prevent upgrades from affecting interoperability. A stronger value is now used in the default files distributed with the software, which was derived from Mozilla's tool.

keyName

string

Specifies a particular credential to use for signing or TLS authentication by attaching a name to the lookup criteria passed to the credential resolver in use. Typically the credential resolver will be able to attach names or aliases to credentials in some fashion. For more on using this feature, see the Multiple Credentials topic.

artifactEndpointIndex

string

Identifies which <ArtifactResolutionService> handler at the SP is used when sending artifact-bound messages to the relying party. Endpoints typically include an index attribute to copy here.

chunkedEncoding

boolean

false

Controls the use of chunked encoding during back-channel SOAP communication. HTTP clients sending data must either compute and send a Content-Length header to the server (requiring that all data be buffered ahead of time), or use chunked encoding. A lot of servers mis-handle this option, so it is disabled by default.

connectTimeout

time in seconds

10

Specifies the timeout for connecting to remote servers during back-channel SOAP communication.

requireConfidentiality

boolean

true

When true, the SP will require the use of TLS/SSL for all back-channel SOAP communication. This prevents an unsafe exchange of data before an unencrypted channel might be used, since XML encryption depends on the peer's willingness to use it.

requireSignedAssertions

boolean

false

When true, assertions MUST be digitally signed, regardless of any other signatures used to authenticate them. Typically needed only for advanced auditing or assertion forwarding use cases.

requireTransportAuth boolean varies When true, the SP will require back-channel SOAP communication to be authenticated at the transport layer (TLS/SSL server authentication). See the the Signing and Encryption topic for additional semantics and how this works by default

sessionHook

URL

Specifies a location to send the client after a session has been created (i.e., after login), but before transferring the client to the eventual final resource. This is normally a relative path to ensure that the session will be visible to the hook script, but doesn't have to be. A hook can be used to validate something about the session to check its "fitness for purpose" before delivering the client to an application that may not offer sufficient error handling capability to do the job itself. A common example is checking for required attributes. The hook redirect will include two parameters, target and return. The target parameter contains the resource URL that will eventually be the client's destination, in case the hook cares. The return parameter is the location to redirect the client back to upon completion of the hook.

The hook MUST either redirect back or take complete ownership of the client with no further processing by the SP.

artifactByFilesystem boolean false Enables the artifact-based "back-door" external authentication mechanism described in the BackDoor topic

authnContextClassRef

whitespace-delimited URIs

Supplies values for the SAML 2.0 <AuthnContextClassRef> element in requests to applicable IdPs, or for the wauth parameter in WS-Federation requests. Ignored for other protocols.

authnContextComparison

"exact", "minimum", "maximum", "better"

Supplies values for the <RequestedAuthenticationContext> comparison operator in SAML 2.0 requests to applicable IdPs. Ignored for other protocols.

NameIDFormat

URI

Supplies a value for the <NameIDPolicy> element's Format attribute in SAML 2.0 requests to applicable IdPs. Ignored for other protocols.

SPNameQualifier

URI

Supplies a value for the <NameIDPolicy> element's SPNameQualifier attribute in SAML 2.0 requests to applicable IdPs. Ignored for other protocols.

Child Elements

If they appear, the first two elements (<Sessions> and <Errors>) MUST be in the order listed. All other elements may be in any order.

Name	Cardinality		Description
	Application Defaults	Application Override
`<Sessions>`	1	0 or 1	Configures the session handling behavior for the application, as well as all of the supported processing handlers and their locations.
`<Errors>`	0 or 1		Configures error-handling behavior and a few logout-related responses
`<RelyingParty>`	0 or more		Overrides low-level communication settings for specific IdPs or groups of IdPs
`<Notify>`	0 or more		Configures application notification of logout or name identifier management messages.
`<MetadataProvider>`	1 or more	0 or more	Details how to load metadata about identity providers.
`<TrustEngine>`	0 or more		Controls how trust processing is performed to determine whether authentication of messages from identity providers succeeds or fails, including XML and simple signing, and SSL/TLS. The default configuration used when nothing is specified is to use the ExplicitKey engine.
`<AttributeExtractor>`	0 or more		Controls how SAML attributes are decoded and exposed to applications.
`<AttributeResolver>`	0 or more		Controls access to other data sources for attribute information. Primary use is for support of SAML queries to an identity provider for attributes if none are received in the initial assertion. When absent, the SP will not query for attributes.
`<AttributeFilter>`	0 or more		Applies rules that filter out unacceptable attribute information.
`<CredentialResolver>`	0 or more		Configures the private keys and certificates used by the SP. This is NOT related to the normal SSL/TLS server support provided by web servers.
`<ApplicationOverride>`	0 or more	0	Overrides default behavior by nesting exceptional configuration elements.
`<ExternalApplicationOverrides>`	0 or more	0	Overrides default behavior through external XML fragments in one or more search paths