From e95e2905324da765bd4c9a2e852600dd885d197e Mon Sep 17 00:00:00 2001
From: Jun Pataleta <jun@moodle.com>
Date: Wed, 29 Mar 2023 08:35:30 +0800
Subject: [PATCH] MDL-77783 core: Validate sublugins.json

* Validate the decoded subplugins.json before processing it.
* Log errors if subplugins.json is invalid or if plugintypes is not
defined.
---
 lib/classes/component.php | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/lib/classes/component.php b/lib/classes/component.php
index eed558d6d80..eb535292c5a 100644
--- a/lib/classes/component.php
+++ b/lib/classes/component.php
@@ -574,7 +574,18 @@ $cache = '.var_export($cache, true).';
         $types = array();
         $subplugins = array();
         if (file_exists("$ownerdir/db/subplugins.json")) {
-            $subplugins = (array) json_decode(file_get_contents("$ownerdir/db/subplugins.json"))->plugintypes;
+            $subplugins = [];
+            $subpluginsjson = json_decode(file_get_contents("$ownerdir/db/subplugins.json"));
+            if (json_last_error() === JSON_ERROR_NONE) {
+                if (!empty($subpluginsjson->plugintypes)) {
+                    $subplugins = (array) $subpluginsjson->plugintypes;
+                } else {
+                    error_log("No plugintypes defined in $ownerdir/db/subplugins.json");
+                }
+            } else {
+                $jsonerror = json_last_error_msg();
+                error_log("$ownerdir/db/subplugins.json is invalid ($jsonerror)");
+            }
         } else if (file_exists("$ownerdir/db/subplugins.php")) {
             error_log('Use of subplugins.php has been deprecated. ' .
                 "Please update your '$ownerdir' plugin to provide a subplugins.json file instead.");