IPAddressAuthnConfiguration

Current File(s): conf/authn/ipaddress-authn-config.xml, conf/authn/authn.properties
Format: Native Spring, Properties

Overview

The authn/IPAddress login flow applies the user agent's address to a mapping of address range(s) to username(s) as a form of pseudo-authentication. This isn't the same as authorizing access to something by address, because a real user identity is produced as a result.

This flow is implemented as a "fall-through" so that under normal error conditions (no address available, no valid mapping), it passes control back to select another flow to run, so it can easily be combined with other methods. Of course, as shipped, the IdP will communicate that the form of authentication done was not based on a password.

Enabling Module

Configuring and using this feature requires that you first enable the "idp.authn.IPAddress" module if it isn't already enabled. Systems upgraded from older releases generally come pre-enabled due to the prior state of the configuration tree.

(Windows)
C:\opt\shibboleth-idp> bin\module.bat -t idp.authn.IPAddress || bin\module.bat -e idp.authn.IPAddress
 
(Other)
$ bin/module.sh -t idp.authn.IPAddress || bin/module.sh -e idp.authn.IPAddress

General Configuration

Use conf/authn/ipaddress-authn-config.xml and conf/authn/authn.properties to configure this flow.

The shibboleth.authn.IPAddress.Mappings bean is the mapping between usernames and lists of CIDR address ranges. An IP CIDR Calculator may help in calculating the CIDR notation for an IP range. Note that en empty map, which is the default, essentially makes this flow non-operable in practice.

The following example maps only the IPv4 and IPv6 localhost addresses to the name "jdoe":

    <util:map id="shibboleth.authn.IPAddress.Mappings">
        <entry key="jdoe">
            <list>
                <value>127.0.0.1/32</value>
                <value>::1/128</value>
            </list>
        </entry>
    </util:map>

The shibboleth.authn.IPAddress.Transforms bean allows for address transformations before comparing them to the address ranges, essentially a kind of on-the-fly address translation. A transform is a Pair object containing a regular expression and a replacement expression.

Reference

Beans

The beans defined in authn/ipaddress-authn-config.xml follow:

Bean ID / Type	Default	Description
shibboleth.authn.IPAddress.Mappings Map<String,List<IPRange>>	Empty map	The entry values are a list of CIDR address range strings to map to the username in the entry key
shibboleth.authn.IPAddress.Transforms List<Pair<String,String>>		Pairs of regular expressions and replacement expressions to apply to the IP address
shibboleth.authn.IPAddress.resultCachingPredicate Predicate<ProfileRequestContext>		An optional bean that can be defined to control whether to preserve the authentication result in an IdP session
shibboleth.authn.IPAddress.ClassifiedMessageMap Map<String,Collection<String>>	Remaps NoCredentials and InvalidCredentials into ReselectFlow for fall-through behavior	Optional remapping of exception messages or events into specific Spring Web Flow events, very rarely needed with this flow

Properties

The general properties configuring this flow via authn/authn.properties are:

Name	Default	Description
idp.authn.IPAddress.order	1000	Flow priority relative to other enabled login flows (lower is "higher" in priority)
idp.authn.IPAddress.nonBrowserSupported	true	Whether the flow should handle non-browser request profiles (e.g., ECP)
idp.authn.IPAddress.passiveAuthenticationSupported	true	Whether the flow allows for passive authentication
idp.authn.IPAddress.forcedAuthenticationSupported	false	Whether the flow supports forced authentication
idp.authn.IPAddress.proxyRestrictionsEnforced	%{idp.authn.enforceProxyRestrictions:true}	Whether the flow enforces upstream IdP-imposed restrictions on proxying
idp.authn.IPAddress.proxyScopingEnforced	false	Whether the flow considers itself to be proxying, and therefore enforces SP-signaled restrictions on proxying
idp.authn.IPAddress.discoveryRequired	false	Whether to invoke IdP-discovery prior to running flow
idp.authn.IPAddress.lifetime	%{idp.authn.defaultLifetime:PT60S}	Lifetime of results produced by this flow
idp.authn.IPAddress.inactivityTimeout	%{idp.authn.defaultTimeout:PT60S}	Inactivity timeout of results produced by this flow
idp.authn.IPAddress.reuseCondition	shibboleth.Conditions.TRUE	Bean ID of Predicate<ProfileRequestContext> controlling result reuse for SSO
idp.authn.IPAddress.activationCondition	shibboleth.Conditions.TRUE	Bean ID of Predicate<ProfileRequestContext> determining whether flow is usable for request
idp.authn.IPAddress.subjectDecorator		Bean ID of BiConsumer<ProfileRequestContext,Subject> for subject customization
idp.authn.IPAddress.supportedPrincipals	(see below)	Comma-delimited list of protocol-specific Principal strings associated with flow
idp.authn.IPAddress.addDefaultPrincipals	true	Whether to auto-attach the preceding set of Principal objects to each Subject produced by this flow

As a non-password based flow, the supportedPrincipals property defaults to the following XML:

<list>
    <bean parent="shibboleth.SAML2AuthnContextClassRef"
        c:classRef="urn:oasis:names:tc:SAML:2.0:ac:classes:InternetProtocol" />
</list>

In property form, this is expressed as:

idp.authn.IPAddress.supportedPrincipals = \
    saml2/urn:oasis:names:tc:SAML:2.0:ac:classes:InternetProtocol

SAML 1 does not define an AuthenticationMethod constant for this kind of authentication, so only a SAML 2 AuthnContextClassRef is applied. An "unspecified" method constant will be used with SAML 1 unless otherwise configured.

Flow Descriptor XML

To replace the internally defined flow descriptor bean, the following XML is required:

<util:list id="shibboleth.AvailableAuthenticationFlows">
 
    <bean p:id="authn/IPAddress" parent="shibboleth.AuthenticationFlow"
            p:order="%{idp.authn.IPAddress.order:1000}"
            p:nonBrowserSupported="%{idp.authn.IPAddress.nonBrowserSupported:true}"
            p:passiveAuthenticationSupported="%{idp.authn.IPAddress.passiveAuthenticationSupported:true}"
            p:forcedAuthenticationSupported="%{idp.authn.IPAddress.forcedAuthenticationSupported:false}"
            p:proxyRestrictionsEnforced="%{idp.authn.IPAddress.proxyRestrictionsEnforced:%{idp.authn.enforceProxyRestrictions:true}}"
            p:proxyScopingEnforced="%{idp.authn.IPAddress.proxyScopingEnforced:false}"
            p:discoveryRequired="%{idp.authn.IPAddress.discoveryRequired:false}"
            p:lifetime="%{idp.authn.IPAddress.lifetime:PT60S}"
            p:inactivityTimeout="%{idp.authn.IPAddress.inactivityTimeout:PT60S}"
            p:reuseCondition-ref="#{'%{idp.authn.IPAddress.reuseCondition:shibboleth.Conditions.TRUE}'.trim()}"
            p:activationCondition-ref="#{'%{idp.authn.IPAddress.activationCondition:shibboleth.Conditions.TRUE}'.trim()}"
            p:subjectDecorator="#{getObject('%{idp.authn.IPAddress.subjectDecorator:}'.trim())}">
        <property name="supportedPrincipalsByString">
            <bean parent="shibboleth.CommaDelimStringArray"
                c:_0="#{'%{idp.authn.IPAddress.supportedPrincipals:}'.trim()}" />
        </property>
    </bean>
 
</util:list>

In older versions and upgraded systems, this list is defined in conf/authn/general-authn.xml. In V5, no default version of the list is provided and it may simply be placed in conf/global.xml if needed.