Index: includes/form.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/form.inc,v
retrieving revision 1.416
diff -u -p -r1.416 form.inc
--- includes/form.inc	5 Dec 2009 16:03:51 -0000	1.416
+++ includes/form.inc	11 Dec 2009 00:54:10 -0000
@@ -688,22 +688,26 @@ function drupal_prepare_form($form_id, &
   // authenticated users. This ensures that any submitted form was actually
   // requested previously by the user and protects against cross site request
   // forgeries.
-  if (isset($form['#token'])) {
-    if ($form['#token'] === FALSE || $user->uid == 0 || $form_state['programmed']) {
+  // This does not apply to programmatically submitted forms. Furthermore, since
+  // tokens are session-bound and forms displayed to anonymous users are very
+  // likely cached, we cannot assign a token for them.
+  // During installation, there is no $user yet.
+  if (!empty($user->uid) && !$form_state['programmed']) {
+    // Form constructors may explicitly set #token to FALSE when cross site
+    // request forgery is irrelevant to the form, such as search forms.
+    if (isset($form['#token']) && $form['#token'] === FALSE) {
       unset($form['#token']);
     }
+    // Otherwise, generate a public token based on the assigned token.
     else {
-      $form['form_token'] = array('#type' => 'token', '#default_value' => drupal_get_token($form['#token']));
+      $form['#token'] = $form_id;
+      $form['form_token'] = array(
+        '#id' => drupal_html_id('edit-' . $form_id . '-form-token'),
+        '#type' => 'token',
+        '#default_value' => drupal_get_token($form['#token']),
+      );
     }
   }
-  elseif (isset($user->uid) && $user->uid && !$form_state['programmed']) {
-    $form['#token'] = $form_id;
-    $form['form_token'] = array(
-      '#id' => drupal_html_id('edit-' . $form_id . '-form-token'),
-      '#type' => 'token',
-      '#default_value' => drupal_get_token($form['#token']),
-    );
-  }
 
   if (isset($form_id)) {
     $form['form_id'] = array(
Index: modules/comment/comment.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/comment/comment.module,v
retrieving revision 1.814
diff -u -p -r1.814 comment.module
--- modules/comment/comment.module	4 Dec 2009 16:49:46 -0000	1.814
+++ modules/comment/comment.module	11 Dec 2009 00:10:29 -0000
@@ -1829,7 +1829,7 @@ function comment_form($form, &$form_stat
   $form['submit'] = array(
     '#type' => 'submit',
     '#value' => t('Save'),
-    '#access' => variable_get('comment_preview_' . $node->type, DRUPAL_OPTIONAL) != DRUPAL_REQUIRED || (!form_get_errors() && isset($form_state['comment_preview'])),
+    '#access' => ($comment->cid && user_access('administer comments')) || variable_get('comment_preview_' . $node->type, DRUPAL_OPTIONAL) != DRUPAL_REQUIRED || (!form_get_errors() && isset($form_state['comment_preview'])),
     '#weight' => 19,
   );
   $form['preview'] = array(
Index: modules/contact/contact.pages.inc
===================================================================
RCS file: /cvs/drupal/drupal/modules/contact/contact.pages.inc,v
retrieving revision 1.37
diff -u -p -r1.37 contact.pages.inc
--- modules/contact/contact.pages.inc	6 Dec 2009 23:56:47 -0000	1.37
+++ modules/contact/contact.pages.inc	11 Dec 2009 00:10:47 -0000
@@ -61,7 +61,6 @@ function contact_site_form($form, &$form
     $form['#attributes']['class'][] = 'user-info-from-cookie';
   }
 
-  $form['#token'] = $user->uid ? $user->name . $user->mail : '';
   $form['name'] = array(
     '#type' => 'textfield',
     '#title' => t('Your name'),
@@ -171,7 +170,7 @@ function contact_site_form_submit($form,
  * @see contact_personal_form_validate()
  * @see contact_personal_form_submit()
  */
-function contact_personal_form($form, &$form_state, stdClass $recipient) {
+function contact_personal_form($form, &$form_state, $recipient) {
   global $user;
 
   // Check if flood control has been activated for sending e-mails.
@@ -190,7 +189,6 @@ function contact_personal_form($form, &$
     $form['#attributes']['class'][] = 'user-info-from-cookie';
   }
 
-  $form['#token'] = $user->uid ? $user->name . $user->mail : '';
   $form['recipient'] = array(
     '#type' => 'value',
     '#value' => $recipient,