Ticket #4049: trac-csrf.patch

trac/env.py

@@ -373 +373 @@
         return self._abs_href
     abs_href = property(_get_abs_href, 'The application URL')
 
+    def _get_form_secret(self):
+        return str(os.stat(os.path.join(self.path, 'VERSION')).st_ctime)
+    form_secret = property(_get_form_secret)
 
+
 class EnvironmentSetup(Component):
     implements(IEnvironmentSetupParticipant)
 

trac/web/chrome.py

@@ -432 +432 @@
             'href': req and req.href,
             'perm': req and req.perm,
             'authname': req and req.authname or '<trac>',
+            'form_token': req.form_token,
 
             # Date/time formatting
             'format_datetime': partial(format_datetime, tzinfo=tzinfo),

trac/web/main.py

@@ -16 +16 @@
 # Author: Christopher Lenz <cmlenz@gmx.de>
 #         Matthew Good <trac@matt-good.net>
 
+import sha
 import locale
 import os
 import sys
@@ -173 +174 @@
             'hdf': self._get_hdf,
             'perm': self._get_perm,
             'session': self._get_session,
-            'tz': self._get_timezone
+            'tz': self._get_timezone,
+            'form_token': self._get_form_token
         })
 
         # Select the component that should handle the request
@@ -193 +195 @@
         req.callbacks['chrome'] = partial(chrome.prepare_request,
                                           handler=chosen_handler)
 
+        if (req.method == 'POST' and
+            req.args.get('__form_token__') != req.form_token):
+            raise TracError('Missing or invalid form token')
+
         # Process the request and render the template
         try:
             try:
@@ -251 +257 @@
         except:
             return localtz
 
+    def _get_form_token(self, req):
+        return sha.sha(self.env.form_secret + req.authname).hexdigest()
+
     def _pre_process_request(self, req, chosen_handler):
         for filter_ in self.filters:
             chosen_handler = filter_.pre_process_request(req, chosen_handler)

templates/layout.html

@@ -80 +80 @@
     </div>
   </body>
 
+  <form py:match="form[@method='post' and @protected!='true']" 
+        method="post" 
+        protected="true"
+        id="${select('@id')}"
+        class="${select('@class')}"
+        action="${select('@action')}">
+    <input type="hidden" name="__form_token__" value="$form_token"/>
+    ${select('*|text()')}
+  </form>
+
   <xi:include href="site.html"><xi:fallback /></xi:include>
 
 </html>