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Copyright (c) 2013, SWITCH - Serving Swiss Universities
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See LICENSE file for details.

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SWITCHwayf Documentation
========================

Find below the documentation and configuration options for the SWITCHwayf.

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**This document is written in the markdown syntax**

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Description
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The SWITCHwayf is an implementation of the Shibboleth WAYF and SAML2 Discovery 
Service protocol for use withing a Shibboleth architecture.

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The features of the SWITCHwayf are:

- Preselecting an entry in drop down list by:
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  - SAML common domain cookie that contains selected Identity Providers 
  - resource path info hint (e.g. 
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    /WAYF/unige.ch?entityID=https://... pre-selects 'University  of Geneva', 
    depends of course on the ID scheme a federation uses
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  - Kerberos preselection
  - IP range preselection
  - IP reverse DNS lookup preselection
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- Supports embedding the WAYF directly into a web page by means of Javascript
- Supports SAML2 metadata
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- Supports Discovery Service and the Shibboleth authentication request protocol 
- Various customizations options for header, footer, language strings etc.
- Support for remembering IdP selection permanently
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- I18N support, currently locales for en, de, it, fr, pt and ja are included
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Customization Options
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Since version 1.12 any graphical aspects can be customized such that these 
changes normally should survive bug-fix and minor version upgrades. 
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Files whose names start with 'default-' can be copied and renamed to start with 
'custom-' in order to  customize the file's behaviour.

In particular, the following customizations can be applied:

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* HTML Header:   custom-header.php  
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  Customize page header
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* HTML Footer:   custom-footer.php  
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Customize page footer 

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* HTML Body:     custom-body.php  
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  Customize WAYF/DS body
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* HTML Body:     custom-settings.php  
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  Customize WAYF/DS permanent settings body
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* HTML Body:     custom-notice.php  
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  Customize WAYF/DS permanent settings notice body
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* HTML Body:     custom-embedded-wayf.php  
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  Customize WAYF/DS body
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* HTML Error:    custom-error.php  
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  Customize error messages
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* CSS Styles:    css/custom-styles.css  
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  Customize CSS styles that are printed inline in header. The custom styles are
  loaded in addition to the default styles. Therefore, they can be used to 
  overwrite the default CSS styles.
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* Languages:     custom-languages.php  
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  Can be used to change default or add new language strings. The custom 
  languages strings in addition to the default styles. Therefore, they can be 
  used to overwrite the default CSS styles.

If the above files don't exist yet, the default templates and settings 
will be used. To create a custom template, copy the default files with:

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`cp default-{$template}.php custom-{$template}.php`
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where {$template} stands for the file you want to customize.

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Logging
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Errors are generally written to syslog. Error messages might be cases where
files cannot be read or written due to permission problems.

If the configuration option $useLogging is true, a log file will be written to 
the path specified in $WAYFLogFile. This log file is an audit log file where 
each line is an entry of the form:

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{DATE} {TIME} {IP} {IDP-SELECTION} {REQUEST-TYPE} {IDP-ENTITYID} {FORWARDING-URL}
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Log entries are only created if the user was forwarded to an Identity Provider.

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- {DATE}             = Date of request, e.g. 2010-11-02
- {TIME}             = Time of request, e.g. 06:25:13
- {IP}               = IP of requester, e.g. 127.0.0.1
- {IDP-SELECTION}    = How the IdP was selected: Cookie or Request
- {REQUEST-TYPE}     = Type of request: DS, WAYF, Embedded-DS, Embedded-WAYF
- {IDP-ENTITYID}     = EntityID of the IdP the user was forwarded to.
- {FORWARDING-URL}   = URL the user was redirected to
- {SP-ENTITYID}      = EntityID of the SP the user was coming from.
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Optimizations
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If your instance of the SWITCHwayf has to deal with many requests and the load 
is becoming  higher and higher, you might want to think about using a PHP opcode 
cacher like XCache, apc,  eaccelerator,  phpa,  truck-mmcache or similar.  

Using such a tool can decrease the processing time of the PHP code almost by 
half. However, own tests have shown that the bottleneck in general is not 
the PHP processing but the TLS handshake, which has nothing to do with PHP 
or the SWITCHwayf itself. 

Benchmark tests conducted by SWITCH demonstrated that generating the 
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Javascript WAYF/embedded-wayf.js can be speed up using XCache by 100% if the 
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script is accessed via HTTP (without TLS). However, if the script is 
accessed via HTTPS (default in SWITCHaai), the overall speed gain by using 
XCache is less than 1% because the TLS hand-shake is what consumes most CPU time.

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SAML2 Metadata support
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In case the WAYF/DS should display the list of IdPs by parsing them from a
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SAML2 Medatadata file that is used by Shibboleth:

- Set $useSAML2Metadata in config.php to true
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- Specify the path to the metadata file that should be read in $metadataFile
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  and make sure this file is updated regularely by Shibboleth or a cron job
- Make sure the files specified in $metadataIDPFile and $metadataSPFile can be 
  written by the userthat executes the PHP script (the web server user, 
  e.g. www-data or _www)

The parsend IDP and SP entries will be stored in $metadataIDPFile and 
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$metadataSPFile as executable PHP code, thus benefiting from opcode caching
(see chapter "Optimization" above).
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If an entry should changed, removed or extended in this automatically 
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generated file, one can extend the IDP definitions by modifying them in 
the $IDPConfigFile. To overwrite IDP values with entries in the $IDPConfigFile, 
make sure the entry $SAML2MetaOverLocalConf is set to 'false';
For example one could change the displayed name of an IdP by adding an entry in
the file $IDPConfigFile like:

$IDProviders["https://sso.example.org/idp/shibboleth"]["Name"] = "Foobar";

It is also possible to manually force the IdP list being upgraded by running the 
readMetadata.php in command line mode, e.g. by executing a cron script like:

5 * * * * /usr/bin/php readMetadata.php > /dev/null

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Embedded WAYF support
---------------------

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With the embedded WAYF support administrators of a Shibboleth protected 
application can easily integrate a Discovery Service on the any page of their 
application just by copying and adapting the HTML code snippet generated by the
SWITCHwayf via the URL /WAYF/embedded-wayf.js/snippet.html

The embedded WAYF then will display on the remote site a drop-down list with the
Identity Provider to authenticate.

One can also configure the embedded WAYF to hide or add Identity Providers 
(even from remote federations) or adapt the look and feel of the embedded wayf. 
This can be done by simpling modifying the JavaScript variables in the HTML 
snippet.


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**Note**
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When activating the Embedded WAYF, carefully protect the host where the WAYF is 
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operated on. If an instance of SWITCHwayf gets compromised, an attacker could 
modify the JavaScript that is embedded on the remote site in a malicous wayf 
(e.g. phish the user's password, redirect users to malicous pages, steal their 
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sessions etc).  
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One also has to ensure that a centrally operated WAYF has a very high availability 
because many services will depend on it.
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Also, please be aware that using the Embedded WAYF allows anybody to guess a 
user's Home Organisation without much effort. This information then could be 
used for phising attacks for example!

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Embedded WAYF code HTML snippet
-------------------------------

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To get a sample HTML snippet to embedd in a web page, please access the WAYF 
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with a URL like:

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https://{HOSTNAME}/{PATH-TO-WAYF}/WAYF/embedded-wayf.js/snippet.html
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The script should return HTML code that can be embedded together with short 
descriptions of the available settings.

Embedded WAYF code limitations:
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* If the embedded WAYF is placed on the right side or at the bottom of a web page,
  it may be that the web browser cannot expand and render the complete drop-down
  list of Identity Providers.
* If placed on a host where no Service Provider is installed, the Embedded WAYF
  might not be able to detect whether a user is logged in or not. Also, the 
  wayf_use_disco_feed might not be used. 
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Kerberos support
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If this features is used, the web server needs to support Negotiate/SPNEGO 
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Kerberos protocol. For example by using mod_auth_kerb.
- Make a symlink of the file 'WAYF' and name it like configured in the variable 
  $kerberosRedirectURL
- Protect file $kerberosRedirectURL with Kerberos. The Kerberos realm must be
  specified in "IDProvider.conf.php" for each IdP. Each IdP's KDC must also
  establish a Kerberos cross-realm trust with the WAYF's KDC. This was tested 
  with a Windows 2000 KDC, with the WAYF running on RHEL4. 

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Configuration file format
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Have a look at the file 'IDProvider.conf.php' for an example of the file format 
that is used to configure the list of Identity Provider to display. It's 
supposed to be mostly self-explanatory. Basically the file format is PHP code 
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that defines an array of arrays called $IDProviders. 
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The keys of the array $IDProviders must correspond to the entityIDs of the 
Identity Providers or a unique value in case of a cascaded WAYF/DS or 
a category. The entityID must be a valid URI (URL or URN) where in the
case of a URN the last component must be a valid hostname.

If metadata is not parsed from SAML2 metadta (using the setting 
$useSAML2Metadata = false), the IdPs and category entries will be displayed 
in order as defined in the configuration file and no sorting is done.

If metadata is used ($useSAML2Metadata = true) to generate the list of Identity 
Providers, the Identity Providers will first be sorted according to their 
type/category, their Index value (see below) and then alphabetically after their 
(local) Name within the same type category. 
If an IdP does not have a type, its category is 'unknown'.
If there exists a type for an IdP that does not have a corresponding category 
it will be displayed in the category 'unknown' at the end of the drop down list 
but will keep its type value (this is important for the Embedded Discovery 
Service).

A general entry for an Identity Provider, a cascaded WAYF/DS or a category is 
of the following form:

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$IDProviders[{KEY}] = {ENTRY}

* {KEY}is a unique value that must correspond to the entity's entityID in case 
  the entry stands for an Identity Provider. For entries of Type category, the
  {KEY'} should be an identifier that corresponds to a 'Type' of an IdP.

* '{ENTRY} is a hash array with the following keys: 

  * ['Type']:   Optional  
    Type that is used for the embedded wayf to hide or show certain categories. 
    Default type will be 'unknown' if not specified.  
    An entry for another WAYF/DS that the user should be redirected to should 
    have ['Type'] ='wayf  
    The Type values 'category' and 'wayf' are reserved words that are not allowed
    to be assigned to entries for Identity Providers.
  
  * ['Name']:   Mandatory  
    Default name to display in drop-down list
  
  * [{LANG}]:   Optional  
    {LANG} is a language identifier, e.g. 'en-GB', 'it', 'fr-F', 'de', ...  
    The value is an array with the following keys:
    - ['Name']:     Optional  
      Display name
    - ['Keywords']: Optional  
      Keywords associated with the Identity Provider.  
      Used for search-as-you-type feature of improved drop-down list. Space delimited.
  
  * ['SSO']:    Mandatory  
    Should be the SAML1 SSO endpoint of the IdP
  * ['Realm']:  Optional  
    Kerberos Realm
  * ['IP'][]:   Optional  
    IP ranges of that organizations that can be used to guess a user's Identity 
     Provider
  * ['Index']:  Optional  
    An alphanumerical value that is used for sorting categories and Identity 
    Provider in ascending order if the Identity Providers are parsed from metadata.  
    This is only relevant if $includeLocalConfEntries = true
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For category entries, only Type, (local) Name and Index are relevant.
The format for the file $metadataSPFile is very similar. 
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A general entry for an Identity Provider, a cascaded WAYF/DS or a category is 
of the following form:

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$metadataSProviders[{KEY}] = {ENTRY}

* {KEY} is a unique value that must correspond to the Service Provider's entityID.

* 'ENTRY} is a hash array with the following keys: 

  * ['Name']:       Mandatory  
    Default name to display in drop-down list. By default the MDUI:DisplayName, 
    the ServiceName or the entityID is used. If there is a display name 
    available in the WAYF's default language that one will be used. Otherwise 
    English or the only  available DisplayName is used.
  
  * [{LANG}]:   Optional  
    {LANG} is a language identifier, e.g. 'en-GB', 'it', 'fr-F', 'de', ...  
    The value is an array with the following keys:
    - ['Name']:     Optional  
      Display name
  
  * ['DSURL']:      Optional  
    List of DiscoveryService endpoints of the SP.
  
  * ['ACURL']:      Mandatory   
    List of Assertion Consumer endpoints of the SP.
  
  * ['Protocols']:  Mandatory   
    Protocols supported by the SP, e.g.: urn:oasis:names:tc:SAML:2.0:protocol
    urn:oasis:names:tc:SAML:1.1:protocol
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Path Info parameters and files
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Modifying the WAYF's URL it is possible to influence its behaviour. This can be
done by appending certain Path Info extension to the URL. The Path Info 
components can also be combined. The allowed syntax is:

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* [/{I18N-STRING}][/redirect][/{ENTITYID-HOSTNAME}]
* [/{I18N-STRING}][/embedded-wayf.js]
* [/embedded-wayf.js/snippet.html]
* [/IDProviders.json]
* [/IDProviders.php]
* [/IDProviders.txt]

**Note:** 
The web server must support the use of Path Info.

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Hinted Identity Provider and transparent redirects
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Path Info Extensions: [/redirect][/{ENTITYID-HOSTNAME}]
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{ENTITYID-HOSTNAME} must be the host name of an entityId or the last component 
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of a URN. Examples:

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* https://aai-login.switch.ch/idp/shibboleth         -> aai-login.switch.ch
* urn:mace:switch.ch:aaitest:aai-demo-idp.switch.ch  -> aai-demo-idp.switch.ch

If '/redirect' is included in the Path Info as well, the web browser is 
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redirected transparently to the specified entityID hostname.

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**Note**
One must make sure that the entityID hostname is not the same as one of
the reserved keywords like 'redirect', the below mentioned file types
or a i18n langauge abbreviation.

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Language preselection:
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Path Info Extensions: [/{I18N-STRING}]
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Examples of {I18N-STRING} strings are 'en', 'de_CH' or 'fr_CH.ISO8859-1' etc. 
However, in the default distribution only 'en', 'de', 'fr', 'it' and 'pt' are 
available and  supported. But it would be easy to create sub types of existing 
languages  for country/region support by adding something like this to 
languages.php:
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// Create a country specific copy of the German language strings  
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$langStrings['de_CH'] = $langStrings['de'];

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// Overwrite a specific string  
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$langStrings['de_CH']['title'] = 'Auswahl der Heimorganisation';

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Special handlers:
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In order for the Embedded WAYF feature to work there are some special files that
need to be generated. The following Path Info Extensions must be the last 
components of the Path Info URL.

Path Info Extensions:
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* [/deleteSettings]  
  As the name suggests, this handler delete all settings cookies that were stored 
  by the WAYF service in cookies. Unless there is a 'return' GET argument 
  provided the user is sent to the settings page.

* [/embedded-wayf.js]  
  Generates the JavaScript for the Embedded WAYF

* [/embedded-wayf.js/snippet.html  
  Generates HTML snippet for the Embedded WAYF

* [/ShibbolethDS-IDProviders.js]  
  Returns JavaScript consisting of only a variable called myJSONObject. It 
  contains the IDProviders array. If $exportPreselectedIdP = true, the last
  element of that array will be a key called 'preselectedIDP', which contains 
  the  Identity Provider that would be preselected in the drop-down list for 
  that user.

* [/ShibbolethDS-IDProviders.json]  
  Same as above but as a JSON data array.

* [/IDProviders.txt]  
  Same as above but in human readable form.

* [/IDProviders.php]  
  Same as above but as PHP code
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