Limits the schemes that Markdown links can use (#22924).

git-svn-id: http://svn.redmine.org/redmine/trunk@15431 e93f8b46-1217-0410-a6f0-8f06a7374b81

lib/redmine/helpers/url.rb

@@ -0,0 +1,35 @@
+# Redmine - project management software
+# Copyright (C) 2006-2016  Jean-Philippe Lang
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+
+require 'uri'
+
+module Redmine
+  module Helpers
+    module URL
+      def uri_with_safe_scheme?(uri, schemes = ['http', 'https', 'ftp', 'mailto', nil])
+        # URLs relative to the current document or document root (without a protocol
+        # separator, should be harmless
+        return true unless uri.include? ":"
+    
+        # Other URLs need to be parsed
+        schemes.include? URI.parse(uri).scheme
+      rescue URI::InvalidURIError
+        false
+      end
+    end
+  end
+end

lib/redmine/wiki_formatting/markdown/formatter.rb

@@ -22,8 +22,11 @@ module Redmine
     module Markdown
       class HTML < Redcarpet::Render::HTML
         include ActionView::Helpers::TagHelper
+        include Redmine::Helpers::URL
 
         def link(link, title, content)
+          return nil unless uri_with_safe_scheme?(link)
+
           css = nil
           unless link && link.starts_with?('/')
             css = 'external'