DOC

Copyright 2012 SWITCH - Serving Swiss Universities. 
See LICENSE file for details.

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SWITCHwayf
Contact: aai@switch.ch or go to http://www.switch.ch/aai/wayf
Version: See head of file 'WAYF' in the same directory
Project web site: https://forge.switch.ch/redmine/projects/wayf
Bug reports/feature requests: https://forge.switch.ch/redmine/projects/wayf/issues
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Description:
The SWITCHwayf is an implementation of the Shibboleth WAYF and SAML2 Discovery 
Service protocol for use withing a Shibboleth architecture.

Some of the Features:
- Preselecting entry in drop down list by
  - SAML common domain cookie that contains selected Identity Providers 
  - resource path info hint (e.g. 
    /WAYF/unige.ch?shire=https://... selects University  of Geneva, depends 
    of course on the ID scheme a federation uses)
  - Kerberos preselection
  - IP range preselection
  - IP reverse DNS lookup preselection
- Transparent redirection mode, e.g. /WAYF/unige.ch/redirect?shire=https://...
- Can read SAML2 metadata files
- Supports Discovery Service and the Shibboleth authentication request protocol 
- Various customizations options for header, footer, language strings etc.
- HTML code generation for embedding the WAYF directly into a web page
- Support for templates
- Support for remembering IdP selection permanently
- I18N support, currently language packs for en, de, it, fr and pt are included

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Customization Options:
Since version 1.12 any graphical aspects of this WAYF/DS implementation can be 
customized such that these changes survive a minor version upgrade. 
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:

HTML header:   custom-header.php
Customize page header

HTML Footer:   custom-footer.php
Customize page footer 

HTML Body:     custom-body.php
Customize WAYF/DS body

HTML Body:     custom-settings.php
Customize WAYF/DS permanent settings body

HTML Body:     custom-notice.php
Customize WAYF/DS permanent settings notice body

HTML Body:     custom-embedded-wayf.php
Customize WAYF/DS body

HTML Error:    custom-error.php
Customize error messages

CSS Styles:    css/custom-styles.css
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.

Languages:     custom-languages.php
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, the default templates and settings 
will be used. To create a custom template, copy of the default files with 
cp default-{$template}.php custom-{$template}.php 
where {$template} stands for the file you want to customize.

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Logging:
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:

#DATE# #TIME# #IP# #IDP_SELECTION# #REQUEST_TYPE# #IDP_ENTITYID# #FORWARDING_URL#

Log entries are only created if the user was forwarded to an Identity Provider.

#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

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Optimizations:
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 
Javascript WAYF/embedded-wayf.js can be speed up usign XCache by 100% if the 
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:
In case the WAYF/DS shall display the list of IdPs by parsing them from a
SAML2 Medatadata file that is used by Shibboleth:

- Set $useSAML2Metadata in config.php to true
- Specify the path to the metadata file that shall be read in $metadataFile
  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 
$metadataSPFile as executable PHP code. Storing parsed information in JSON or 
PHP serialized format would allow slightly faster reading and executing in 
general. However, for large numbers of entities an opcode cacher might speed up 
execution time considerably (see chapter "Optimization" above) thanks to 
this format. 

If an entry shall be changed, removed or extended in this automatically 
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

This feature has been initially developed in the framework of GRNET's project 
VNOC by Pavlos Drandakis.

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Embedded WAYF support:
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.


Note:
When activating the Embedded WAYF, carefully protect the host where the WAYF is 
operated on. If your WAYF host 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 sessions etc). 
You also have to make sure that your central WAYF has a very high availability 
because a lot of third-party services will depend on it.

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

https://#HOSTNAME#/#PATH_TO_WAYF#/WAYF/embedded-wayf.js/snippet.html

The script should return HTML code that can be embedded together with short 
descriptions of the available settings.

Embedded WAYF code limitations:
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 wheter a user is logged in or not. Also, the 
wayf_use_disco_feed might not be used. 

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Kerberos support:
If this features shall be used the web server needs to support Negotiate/SPNEGO 
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. 

Credits for this feature go to Josh Howlett from Bristol University.

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Configuration file format:
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 
that defines an array of arrays called $IDProviders.

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:
$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 shall 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

['en'|'it'|'fr'|'de'|...]   Language dependent:
   ['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


For category entries, only Type, (local) Name and Index are relevant.

The format for the file $metadataSPFile looks very similar:

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

$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.
['en'|'it'|'fr'|'de'|'pt']['Name']:
                Optional    Display name in other languages
['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:
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:

[/#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.

Hinted Identity Provider and transparent redirects
--------------------------------------------------
Path Info Extensions: [/redirect][/#entityID hostname#]

#entityID hostname# must be the host name of an entityId or the last component 
of a URN. Examples:
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 the '/redirect' is included in the Path Info as well, the web browser is 
redirected transparently to the specified entityID hostname.

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.

Language preselection:
----------------------
Path Info Extensions: [/#i18n string#]

Examples of i18n 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:

--
// Create a country specific copy of the German language strings
$langStrings['de_CH'] = $langStrings['de'];

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


Special handlers:
-----------------
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:
[/deleteSettings]                  As the name suggests, this handler deletes
                                   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
[/idps-and-state.json]             Returns JSON data structure that contains
                                   the content of the IDProviders array. 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.
[/IDProviders.txt]                 Same as above but in human readable form.
[/IDProviders.php]                 Same as above but as PHP code