From 95b3edd4ce3c50174179f7bba3f40e2b66003286 Mon Sep 17 00:00:00 2001
From: Dion Hulse <dd32@git.wordpress.org>
Date: Mon, 7 Sep 2015 02:38:12 +0000
Subject: [PATCH] Cron: Reject events when the provided `$timestamp` is not a
 valid timestamp.

Invalid timestamps were previously accepted by the scheduling functions but would never be run due to our implementation which caused the cron option to forever contain the events.
This rejects such events which most likely only occur due to developer error.

Props utkarshpatel, wonderboymusic, SergeyBiryukov.
See #33423, Fixes #33475


git-svn-id: https://develop.svn.wordpress.org/trunk@33936 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/cron.php | 30 +++++++++++++++++++++++++-----
 1 file changed, 25 insertions(+), 5 deletions(-)

diff --git a/src/wp-includes/cron.php b/src/wp-includes/cron.php
index 8b88c1220b..97460d8fbd 100644
--- a/src/wp-includes/cron.php
+++ b/src/wp-includes/cron.php
@@ -18,13 +18,18 @@
  * @param int $timestamp Timestamp for when to run the event.
  * @param string $hook Action hook to execute when cron is run.
  * @param array $args Optional. Arguments to pass to the hook's callback function.
- * @return void|false
+ * @return false|void False when an event is not scheduled.
  */
 function wp_schedule_single_event( $timestamp, $hook, $args = array()) {
-	// don't schedule a duplicate if there's already an identical event due within 10 minutes of it
+	// Make sure timestamp is a positive integer
+	if ( ! is_numeric( $timestamp ) || $timestamp <= 0 ) {
+		return false;
+	}
+
+	// Don't schedule a duplicate if there's already an identical event due within 10 minutes of it
 	$next = wp_next_scheduled($hook, $args);
 	if ( $next && abs( $next - $timestamp ) <= 10 * MINUTE_IN_SECONDS ) {
-		return;
+		return false;
 	}
 
 	$crons = _get_cron_array();
@@ -67,9 +72,14 @@ function wp_schedule_single_event( $timestamp, $hook, $args = array()) {
  * @param string $recurrence How often the event should recur.
  * @param string $hook Action hook to execute when cron is run.
  * @param array $args Optional. Arguments to pass to the hook's callback function.
- * @return false|void False when does not schedule event.
+ * @return false|void False when an event is not scheduled.
  */
 function wp_schedule_event( $timestamp, $recurrence, $hook, $args = array()) {
+	// Make sure timestamp is a positive integer
+	if ( ! is_numeric( $timestamp ) || $timestamp <= 0 ) {
+		return false;
+	}
+
 	$crons = _get_cron_array();
 	$schedules = wp_get_schedules();
 
@@ -100,9 +110,14 @@ function wp_schedule_event( $timestamp, $recurrence, $hook, $args = array()) {
  * @param string $recurrence How often the event should recur.
  * @param string $hook Action hook to execute when cron is run.
  * @param array $args Optional. Arguments to pass to the hook's callback function.
- * @return false|void False when does not schedule event.
+ * @return false|void False when an event is not scheduled.
  */
 function wp_reschedule_event( $timestamp, $recurrence, $hook, $args = array() ) {
+	// Make sure timestamp is a positive integer
+	if ( ! is_numeric( $timestamp ) || $timestamp <= 0 ) {
+		return false;
+	}
+
 	$crons = _get_cron_array();
 	$schedules = wp_get_schedules();
 	$key = md5( serialize( $args ) );
@@ -148,6 +163,11 @@ function wp_reschedule_event( $timestamp, $recurrence, $hook, $args = array() )
  * as those used when originally scheduling the event.
  */
 function wp_unschedule_event( $timestamp, $hook, $args = array() ) {
+	// Make sure timestamp is a positive integer
+	if ( ! is_numeric( $timestamp ) || $timestamp <= 0 ) {
+		return false;
+	}
+
 	$crons = _get_cron_array();
 	$key = md5(serialize($args));
 	unset( $crons[$timestamp][$hook][$key] );