Implement token system to fix CSRF vulnerabilities

Specially crafted pages can force authenticated users to unknowingly perform
actions on the AUR website despite being on an attacker's website. This
cross-site request forgery (CSRF) vulnerability applies to all POST data on
the AUR.

Implement a token system using a double submit cookie. Have a hidden form
value on every page containing POST forms. Use the newly added check_token() to
verify the token sent via POST matches the "AURSID" cookie value. Random
nature of the token limits potential for CSRF.

Signed-off-by: canyonknight <canyonknight@gmail.com>
Signed-off-by: Lukas Fleischer <archlinux@cryptocrack.de>

6 files changed, 10 insertions, 2 deletions

diff --git a/web/template/actions_form.php b/web/template/actions_form.php
index 68d83d73..fa6ad72f 100644
--- a/web/template/actions_form.php
+++ b/web/template/actions_form.php
@@ -3,6 +3,7 @@
 		<fieldset>
 			<input type='hidden' name='IDs[<?php echo $row['ID'] ?>]' value='1' />
 			<input type='hidden' name='ID' value="<?php echo $row['ID'] ?>" />
+			<input type='hidden' name='token' value="<?php echo htmlspecialchars($_COOKIE['AURSID']) ?>" />
 <?php
 		# Voting Button
 		#
diff --git a/web/template/pkg_comment_form.php b/web/template/pkg_comment_form.php
index d3b602cd..60816436 100644
--- a/web/template/pkg_comment_form.php
+++ b/web/template/pkg_comment_form.php
@@ -1,6 +1,6 @@
 <?php
 # Add a comment to this package
-if (isset($_REQUEST['comment'])) {
+if (isset($_REQUEST['comment']) && check_token()) {
 
 	# Insert the comment
 	$dbh = db_connect();
@@ -53,13 +53,14 @@ if (isset($_REQUEST['comment'])) {
 	<form action='<?php echo $_SERVER['REQUEST_URI'] ?>' method='post'>
 	<div style="padding: 1%">
 <?php
-if (isset($_REQUEST['comment'])) {
+if (isset($_REQUEST['comment']) && check_token()) {
 	echo '<b>' . __('Comment has been added.') . '</b>';
 }
 ?>
 	<input type='hidden' name='ID' value="<?php echo intval($_REQUEST['ID']) ?>" />
 	<?php echo __('Enter your comment below.') ?><br />
 	<textarea name='comment' cols='80' rows='10' style="width: 100%"></textarea><br />
+	<input type='hidden' name='token' value='<?php echo htmlspecialchars($_COOKIE['AURSID']) ?>' />
 	<input type='submit' value="<?php echo __("Submit") ?>" />
 	<input type='reset' value="<?php echo __("Reset") ?>" />
 	</div>
diff --git a/web/template/pkg_comments.php b/web/template/pkg_comments.php
index aed9ca8b..9dd50041 100644
--- a/web/template/pkg_comments.php
+++ b/web/template/pkg_comments.php
@@ -15,6 +15,7 @@ while (list($indx, $carr) = each($comments)) { ?>
 		$durl.= '<fieldset style="display:inline;">';
 		$durl.= '<input type="hidden" name="action" value="do_DeleteComment" />';
 		$durl.= '<input type="hidden" name="comment_id" value="'.$carr['ID'].'" />';
+		$durl.= '<input type="hidden" name="token" value="'.htmlspecialchars($_COOKIE['AURSID']).'" />';
 		$durl.= '<input type="image" src="images/x.png" ';
 		$durl.= ' alt="'.__("Delete comment").'" name="submit" value="1" ';
 		$durl.= ' />&nbsp;';
diff --git a/web/template/pkg_details.php b/web/template/pkg_details.php
index 046f836b..193af848 100644
--- a/web/template/pkg_details.php
+++ b/web/template/pkg_details.php
@@ -10,6 +10,9 @@ if ($uid == $row["MaintainerUID"] or
 	$edit_cat = "<form method='post' action='packages.php?ID=".$pkgid."'>\n";
 	$edit_cat.= "<p>";
 	$edit_cat.= "<input type='hidden' name='action' value='do_ChangeCategory' />";
+	if ($SID) {
+		$edit_cat.= "<input type='hidden' name='token' value='".htmlspecialchars($_COOKIE['AURSID'])."' />";
+	}
 	$edit_cat.= "<span class='f3'>" . __("Category") . ":</span> ";
 	$edit_cat.= "<select name='category_id'>\n";
 	foreach ($catarr as $cid => $catname) {
diff --git a/web/template/pkg_search_results.php b/web/template/pkg_search_results.php
index e576e6e3..609dc191 100644
--- a/web/template/pkg_search_results.php
+++ b/web/template/pkg_search_results.php
@@ -114,6 +114,7 @@ for ($i = 0; $row = mysql_fetch_assoc($result); $i++) {
 							<input type='text' id='merge_Into' name='merge_Into' />
 							<input type='checkbox' name='confirm_Delete' value='1' /> <?php print __("Confirm") ?>
 						<?php endif; ?>
+						<input type='hidden' name='token' value='<?php print htmlspecialchars($_COOKIE['AURSID']) ?>' />
 						<input type='submit' class='button' style='width: 80px' value='<?php print __("Go") ?>' />
 					</div>
 				<?php endif; # if ($SID) ?>
diff --git a/web/template/tu_details.php b/web/template/tu_details.php
index 7d6c305d..dde53a8c 100644
--- a/web/template/tu_details.php
+++ b/web/template/tu_details.php
@@ -70,6 +70,7 @@ if (!$isrunning) { ?>
 <input type='submit' class='button' name='voteNo' value='<?php print __("No") ?>' />
 <input type='submit' class='button' name='voteAbstain' value='<?php print __("Abstain") ?>' />
 <input type='hidden' name='doVote' value='1' />
+<input type='hidden' name='token' value='<?php print htmlspecialchars($_COOKIE['AURSID']) ?>' />
 </fieldset>
 </form>
 <?php } else { ?>