APM Sharepoint authentication

Problem this snippet solves:

Updated version to support Webdav with windows explorer after Nicolas's comment.

APM is a great authentication service but it does it only with forms.

The default behavior is to redirect user to /my.policy to process VPE. this redirect is only supported for GET method.

Sharepoint provide 3 different access types:

• browsing web site with a browser
• Editing documents with Office
• browser folder with webdav client (or editing documents with libreoffice through webdav protocol)

This irule display best authentication method for each of these access types:

• browsers authenticate with default authentication method (form based authentication)
• Microsoft office authenticate with Form based authentication (with support of MS-OFBA protocol)
• Libreoffice and webdav clients authenticate with 401 basic authentication

Form based authentication (browser and Microsoft office) is compatible (validated for one customer) with SAML authentication

Editing documents is managed with a persistent cookie expiring after 5 minutes. to be shared between IE and Office, it requires :

• cookie is persistent (expiration date instead of deleted at the end of session)
• web site defined as "trusted sites" in IE.

How to use this snippet:

install this irule and enable it on the VS.

Code :

when RULE_INIT {
    array set static::MSOFBA {
        ReqHeader "X-FORMS_BASED_AUTH_REQUIRED"
        ReqVal "/sp-ofba-form"
        ReturnHeader "X-FORMS_BASED_AUTH_RETURN_URL"
        ReturnVal "/sp-ofba-completed"
        SizeHeader "X-FORMS_BASED_AUTH_DIALOG_SIZE"
        SizeVal "800x600"
    }
   set static::ckname "MRHSession_SP"
   set static::Basic_Realm_Text "SharePoint Authentication"
}

when HTTP_REQUEST {
   set apmsessionid [HTTP::cookie value MRHSession]
   set persist_cookie [HTTP::cookie value $static::ckname]
   set clientless_mode 0
   set form_mode 0
   # Identify User-Agents type
   if {[HTTP::header exists "X-FORMS_BASED_AUTH_ACCEPTED"] && (([HTTP::header "X-FORMS_BASED_AUTH_ACCEPTED"] equals "t") || ([HTTP::header "X-FORMS_BASED_AUTH_ACCEPTED"] equals "f"))} {
      set clientless_mode 0; set form_mode 1
   } else {
      switch -glob [string tolower [HTTP::header "User-Agent"]] {
        "*microsoft-webdav-miniredir*" { set clientless_mode 1 }
         "*microsoft data access internet publishing provider*" -
         "*office protocol discovery*" -
         "*microsoft office*" -
         "*non-browser*" -
         "msoffice 12*" { set form_mode 1 }
         "*mozilla/4.0 (compatible; ms frontpage*" {
            if { [ string range [getfield [string tolower [HTTP::header "User-Agent"]] "MS FrontPage " 2] 0 1]  > 12 } {
               set form_mode 1
            } else {
               set clientless_mode 1
            }
         }
         "*mozilla*" -
         "*opera*" { set clientless_mode 0 }
         default { set clientless_mode 1
         }
      }
   }
   if { $clientless_mode || $form_mode } {
      if { [HTTP::cookie exists "MRHSession"] } {set apmstatus [ACCESS::session exists -state_allow $apmsessionid]} else {set apmstatus 0}
      if { !($apmstatus) && [HTTP::cookie exists $static::ckname] } {set apmpersiststatus [ACCESS::session exists -state_allow $persist_cookie]} else {set apmpersiststatus 0}
      if { ($apmpersiststatus) && !($apmstatus) } {
         # Add MRHSession cookie for non browser user-agent first request and persistent cookie present
         if { [catch {HTTP::cookie insert name "MRHSession" value $persist_cookie} ] } {log local0. "[IP::client_addr]:[TCP::client_port] : TCL error on HTTP cookie insert MRHSession : URL : [HTTP::host][HTTP::path] - Headers : [HTTP::request]"} else {return}
      }
   } else { return }      
   if { $clientless_mode && !($apmstatus)} {
      if { !([HTTP::header Authorization] == "") } {
         set clientless(insert_mode) 1
         set clientless(username)    [ string tolower [HTTP::username] ]
         set clientless(password)    [HTTP::password]
         binary scan [md5 "$clientless(password)"] H* clientless(hash)
         set user_key "$clientless(username).$clientless(hash)"
         set clientless(cookie_list)             [ ACCESS::user getsid $user_key ]
         if { [ llength $clientless(cookie_list) ] != 0 } {
            set clientless(cookie) [ ACCESS::user getkey [ lindex $clientless(cookie_list) 0 ] ]
            if { $clientless(cookie) != "" } {
               HTTP::cookie insert name MRHSession value $clientless(cookie)
               set clientless(insert_mode) 0
            }
         }
         if { $clientless(insert_mode) } {
            HTTP::header insert "clientless-mode" 1
            HTTP::header insert "username" $clientless(username)
            HTTP::header insert "password" $clientless(password)
        }
        unset clientless
      } else {
        HTTP::respond 401 WWW-Authenticate "Basic realm=\"$static::Basic_Realm_Text\"" Set-Cookie "MRHSession=deleted; expires=Thu, 01-Jan-1970 00:00:01 GMT; path=/" Connection close
        return
      }
   } elseif {$form_mode && !($apmstatus) && !([HTTP::path] equals $static::MSOFBA(ReqVal))}{
      HTTP::respond 403 -version "1.1" noserver \
         $static::MSOFBA(ReqHeader) "https://[HTTP::host]$static::MSOFBA(ReqVal)" \
         $static::MSOFBA(ReturnHeader) "https://[HTTP::host]$static::MSOFBA(ReturnVal)" \
         $static::MSOFBA(SizeHeader) $static::MSOFBA(SizeVal) \
         "Connection" "Close"
      return
   }
}


when HTTP_RESPONSE {
   # Insert persistent cookie for html content type and private session
   if { [HTTP::header "Content-Type" ] contains "text/html" } {
      HTTP::cookie remove $static::ckname
      HTTP::cookie insert name $static::ckname value $apmsessionid path "/"
      HTTP::cookie expires $static::ckname 120 relative
      HTTP::cookie secure $static::ckname enable
   }
   # Insert session cookie if session was recovered from persistent cookie
   if { ([info exists "apmpersiststatus"]) && ($apmpersiststatus) } {
         HTTP::cookie insert name MRHSession value $persist_cookie path "/"
         HTTP::cookie secure MRHSession enable
   }
}

when ACCESS_SESSION_STARTED {
   if {([info exists "clientless_mode"])} {
      ACCESS::session data set session.clientless $clientless_mode
   }
   if { [ info exists user_key ] } {
      ACCESS::session data set "session.user.uuid" $user_key
   }
}

when ACCESS_POLICY_COMPLETED {
   if { ([info exists "clientless_mode"]) && ($clientless_mode) && ([ACCESS::policy result] equals "deny") } {
      ACCESS::respond 401 noserver WWW-Authenticate "Basic realm=$static::Basic_Realm_Text" Connection close
      ACCESS::session remove
   } 
}

when ACCESS_ACL_ALLOWED {
   switch -glob [string tolower [HTTP::path]] {
      "/sp-ofba-form" {
         ACCESS::respond 302 noserver Location "https://[HTTP::host]$static::MSOFBA(ReturnVal)"
      }
      "/sp-ofba-completed" {
         ACCESS::respond 200 content {
            
               
               Good Work, you are Authenticated
            
         } noserver
      }
      "*/signout.aspx" {
         # Disconnect session and redirect to APM logout Page
         ACCESS::respond 302 noserver Location "/vdesk/hangup.php3"
         return
      }
      "/_layouts/accessdenied.aspx" {
         # Disconnect session and redirect to APM Logon Page
         if {[string tolower [URI::query [HTTP::uri] loginasanotheruser]] equals "true" } {
            ACCESS::session remove
            ACCESS::respond 302 noserver Location "/"
            return
         }
      }
      default {
         # No Actions
      }
   }
}

Tested this on version: