From 2c93f0a98f0f6380fd07ea17fd16afa2c6e4925b Mon Sep 17 00:00:00 2001
From: canyonknight <canyonknight@gmail.com>
Date: Sat, 23 Jun 2012 14:40:11 -0400
Subject: 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>
---
 web/html/addvote.php | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

(limited to 'web/html/addvote.php')

diff --git a/web/html/addvote.php b/web/html/addvote.php
index f0e7d31a..a5ec4a1f 100644
--- a/web/html/addvote.php
+++ b/web/html/addvote.php
@@ -16,7 +16,11 @@ if (isset($_COOKIE["AURSID"])) {
 if ($atype == "Trusted User" OR $atype == "Developer") {
 	$dbh = db_connect();
 
-	if (!empty($_POST['addVote'])) {
+	if (!empty($_POST['addVote']) && !check_token()) {
+		$error = __("Invalid token for user action.");
+	}
+
+	if (!empty($_POST['addVote']) && check_token()) {
 		$error = "";
 
 		if (!empty($_POST['user'])) {
@@ -99,6 +103,7 @@ if ($atype == "Trusted User" OR $atype == "Developer") {
 <b><?php print __('Proposal') ?></b><br />
 <textarea name='agenda' rows='25' cols='80'><?php if (!empty($_POST['agenda'])) { print htmlentities($_POST['agenda']); } ?></textarea><br />
 <input type='hidden' name='addVote' value='1' />
+<input type='hidden' name='token' value='<?php print htmlspecialchars($_COOKIE['AURSID']) ?>' />
 <input type='submit' class='button' value='<?php print __('Submit'); ?>' />
 </p>
 </form>
-- 
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