Improve handling of misconfigured LDAP accounts.

Gitlab requires an email address for all user accounts as this is the
default account id and is used for sending notifications. LDAP accounts
may be missing email fields so handle this by showing a sensible error
message before redirecting to the login screen again.

Resolves github issue #899
Signed-off-by: Pat Thoyts <patthoyts@users.sourceforge.net>

app/controllers/omniauth_callbacks_controller.rb

 class OmniauthCallbacksController < Devise::OmniauthCallbacksController
 
+  # Extend the standard message generation to accept our custom exception
+  def failure_message
+    exception = env["omniauth.error"]
+    if exception.class == OmniAuth::Error
+      error = exception.message
+    else
+      error   = exception.error_reason if exception.respond_to?(:error_reason)
+      error ||= exception.error        if exception.respond_to?(:error)
+      error ||= env["omniauth.error.type"].to_s
+    end
+    error.to_s.humanize if error
+  end
+ 
   def ldap
     # We only find ourselves here if the authentication to LDAP was successful.
     info = request.env["omniauth.auth"]["info"]

app/models/user.rb

@@ -80,7 +80,8 @@ class User < ActiveRecord::Base
 
   def self.find_for_ldap_auth(omniauth_info)
     name = omniauth_info.name.force_encoding("utf-8")
-    email = omniauth_info.email.downcase
+    email = omniauth_info.email.downcase unless omniauth_info.email.nil?
+    raise OmniAuth::Error, "LDAP accounts must provide an email address" if email.nil?
 
     if @user = User.find_by_email(email)
       @user