Query: Non-scalar and negative values for 'p' should always result in a 404.

Previously, the 'p' query var was being run through `absint()`, which
caused unexpected results.

Props Akeif, kouratoras.
Fixes #33372.
Built from https://develop.svn.wordpress.org/trunk@38288


git-svn-id: http://core.svn.wordpress.org/trunk@38229 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/query.php

@@ -1602,7 +1602,13 @@ class WP_Query {
 		if ( ! empty($qv['robots']) )
 			$this->is_robots = true;
 
-		$qv['p'] =  absint($qv['p']);
+		if ( ! is_scalar( $qv['p'] ) || $qv['p'] < 0 ) {
+			$qv['p'] = 0;
+			$qv['error'] = '404';
+		} else {
+			$qv['p'] = intval( $qv['p'] );
+		}
+
 		$qv['page_id'] =  absint($qv['page_id']);
 		$qv['year'] = absint($qv['year']);
 		$qv['monthnum'] = absint($qv['monthnum']);

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.7-alpha-38286';
+$wp_version = '4.7-alpha-38288';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.