From e98f933857548be9cd078416a93011ea9c2f3e3a Mon Sep 17 00:00:00 2001
From: Steve Clay <steve@mrclay.org>
Date: Mon, 10 Jun 2013 23:16:45 -0400
Subject: Allow regenerating site secret

---
 engine/lib/actions.php                             | 27 ++++++++++++++++++++--
 engine/lib/admin.php                               |  2 ++
 ...3060900-1.8.15-site_secret-404fc165cf9e0ac9.php | 13 +++++++++++
 3 files changed, 40 insertions(+), 2 deletions(-)
 create mode 100644 engine/lib/upgrades/2013060900-1.8.15-site_secret-404fc165cf9e0ac9.php

(limited to 'engine/lib')

diff --git a/engine/lib/actions.php b/engine/lib/actions.php
index 56936f582..8047914ac 100644
--- a/engine/lib/actions.php
+++ b/engine/lib/actions.php
@@ -364,16 +364,19 @@ function generate_action_token($timestamp) {
 }
 
 /**
- * Initialise the site secret hash.
+ * Initialise the site secret (32 bytes: "z" to indicate format + 186-bit key in Base64 URL).
  *
  * Used during installation and saves as a datalist.
  *
+ * Note: Old secrets were hex encoded.
+ *
  * @return mixed The site secret hash or false
  * @access private
  * @todo Move to better file.
  */
 function init_site_secret() {
-	$secret = md5(rand() . microtime());
+	$secret = 'z' . ElggCrypto::getRandomString(31);
+
 	if (datalist_set('__site_secret__', $secret)) {
 		return $secret;
 	}
@@ -399,6 +402,26 @@ function get_site_secret() {
 	return $secret;
 }
 
+/**
+ * Get the strength of the site secret
+ *
+ * @return string "strong", "moderate", or "weak"
+ * @access private
+ */
+function _elgg_get_site_secret_strength() {
+	$secret = get_site_secret();
+	if ($secret[0] !== 'z') {
+		$rand_max = getrandmax();
+		if ($rand_max < pow(2, 16)) {
+			return 'weak';
+		}
+		if ($rand_max < pow(2, 32)) {
+			return 'moderate';
+		}
+	}
+	return 'strong';
+}
+
 /**
  * Check if an action is registered and its script exists.
  *
diff --git a/engine/lib/admin.php b/engine/lib/admin.php
index 7f82108c0..f36f29668 100644
--- a/engine/lib/admin.php
+++ b/engine/lib/admin.php
@@ -236,6 +236,7 @@ function admin_init() {
 	elgg_register_action('admin/site/update_advanced', '', 'admin');
 	elgg_register_action('admin/site/flush_cache', '', 'admin');
 	elgg_register_action('admin/site/unlock_upgrade', '', 'admin');
+	elgg_register_action('admin/site/regenerate_secret', '', 'admin');
 
 	elgg_register_action('admin/menu/save', '', 'admin');
 
@@ -291,6 +292,7 @@ function admin_init() {
 	elgg_register_admin_menu_item('configure', 'settings', null, 100);
 	elgg_register_admin_menu_item('configure', 'basic', 'settings', 10);
 	elgg_register_admin_menu_item('configure', 'advanced', 'settings', 20);
+	elgg_register_admin_menu_item('configure', 'advanced/site_secret', 'settings', 25);
 	elgg_register_admin_menu_item('configure', 'menu_items', 'appearance', 30);
 	elgg_register_admin_menu_item('configure', 'profile_fields', 'appearance', 40);
 	// default widgets is added via an event handler elgg_default_widgets_init() in widgets.php
diff --git a/engine/lib/upgrades/2013060900-1.8.15-site_secret-404fc165cf9e0ac9.php b/engine/lib/upgrades/2013060900-1.8.15-site_secret-404fc165cf9e0ac9.php
new file mode 100644
index 000000000..b5b614762
--- /dev/null
+++ b/engine/lib/upgrades/2013060900-1.8.15-site_secret-404fc165cf9e0ac9.php
@@ -0,0 +1,13 @@
+<?php
+/**
+ * Elgg 1.8.15 upgrade 2013060900
+ * site_secret
+ *
+ * Description
+ */
+
+$strength = _elgg_get_site_secret_strength();
+
+if ($strength !== 'strong') {
+	elgg_add_admin_notice('weak_site_key', elgg_echo("upgrade:site_secret_warning:$strength"));
+}
-- 
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