From 0cd14b3a4bdcd740f98fb4deb8afd71974888a40 Mon Sep 17 00:00:00 2001
From: Jean-Philippe Lang <jp_lang@yahoo.fr>
Date: Sun, 2 Feb 2020 08:39:22 +0000
Subject: [PATCH] Validate back_url everywhere (#32850).

Patch by Holger Just.

git-svn-id: http://svn.redmine.org/redmine/trunk@19488 e93f8b46-1217-0410-a6f0-8f06a7374b81
---
 app/controllers/application_controller.rb  |  7 ++++---
 app/helpers/application_helper.rb          |  4 ++--
 test/functional/timelog_controller_test.rb | 13 +++++++++++++
 3 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index e0ea88553..1559affce 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -428,9 +428,8 @@ class ApplicationController < ActionController::Base
   helper_method :back_url
 
   def redirect_back_or_default(default, options={})
-    back_url = params[:back_url].to_s
-    if back_url.present? && valid_url = validate_back_url(back_url)
-      redirect_to(valid_url)
+    if back_url = validate_back_url(params[:back_url].to_s)
+      redirect_to(back_url)
       return
     elsif options[:referer]
       redirect_to_referer_or default
@@ -443,6 +442,8 @@ class ApplicationController < ActionController::Base
   # Returns a validated URL string if back_url is a valid url for redirection,
   # otherwise false
   def validate_back_url(back_url)
+    return false if back_url.blank?
+
     if CGI.unescape(back_url).include?('..')
       return false
     end
diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index 6a7812e4a..9fb6a56c2 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -1426,12 +1426,12 @@ module ApplicationHelper
   end
 
   def back_url_hidden_field_tag
-    url = back_url
+    url = validate_back_url(back_url)
     hidden_field_tag('back_url', url, :id => nil) unless url.blank?
   end
 
   def cancel_button_tag(fallback_url)
-    url = back_url.blank? ? fallback_url : back_url
+    url = validate_back_url(back_url) || fallback_url
     link_to l(:button_cancel), url
   end
 
diff --git a/test/functional/timelog_controller_test.rb b/test/functional/timelog_controller_test.rb
index 3c14e8e7b..f1764b7c9 100644
--- a/test/functional/timelog_controller_test.rb
+++ b/test/functional/timelog_controller_test.rb
@@ -173,6 +173,19 @@ class TimelogControllerTest < Redmine::ControllerTest
     assert_select 'select[name=?]', 'time_entry[project_id]'
   end
 
+  def test_get_edit_should_validate_back_url
+    @request.session[:user_id] = 2
+
+    get :edit, :params => {:id => 2, :project_id => nil, :back_url => '/valid'}
+    assert_response :success
+    assert_select 'a[href=?]', '/valid', {:text => 'Cancel'}
+
+    get :edit, :params => {:id => 2, :project_id => nil, :back_url => 'invalid'}
+    assert_response :success
+    assert_select 'a[href=?]', 'invalid', {:text => 'Cancel', :count => 0}
+    assert_select 'a[href=?]', '/projects/ecookbook/time_entries', {:text => 'Cancel'}
+  end
+
   def test_post_create
     @request.session[:user_id] = 3
     assert_difference 'TimeEntry.count' do
-- 
2.39.5