Allow getAttr to return DN

Specify "DN" as attribute name to return, but will only work if not present in ldap.Entry.Attributes
Use when full DN is stored in groupSearch's userAttr

Documentation/ldap-connector.md

@@ -11,7 +11,9 @@ The connector executes two primary queries:
 
 ## Configuration
 
-User entries are expected to have an email attribute (configurable through `emailAttr`), and a display name attribute (configurable through `nameAttr`). The following is an example config file that can be used by the LDAP connector to authenticate a user.
+User entries are expected to have an email attribute (configurable through `emailAttr`), and a display name attribute (configurable through `nameAttr`). `*Attr` attributes could be set to "DN" in situations where it is needed but not available elsewhere, and if "DN" attribute does not exist in the record.
+
+The following is an example config file that can be used by the LDAP connector to authenticate a user.
 
 ```yaml
 

connector/ldap/ldap.go

@@ -47,6 +47,9 @@ import (
 //         baseDN: cn=groups,dc=example,dc=com
 //         filter: "(objectClass=group)"
 //         userAttr: uid
+//         # Use if full DN is needed and not available as any other attribute
+//         # Will only work if "DN" attribute does not exist in the record
+//         # userAttr: DN
 //         groupAttr: member
 //         nameAttr: name
 //
@@ -285,6 +288,9 @@ func getAttr(e ldap.Entry, name string) string {
 		}
 		return a.Values[0]
 	}
+	if name == "DN" {
+		return e.DN
+	}
 	return ""
 }