MDL-71991 files: check return value of rename when writing files

moodle · Jun 22, 2021 · 1af2572 · 1af2572
1 parent 338b60f
commit 1af2572
Showing 1 changed file with 16 additions and 2 deletions.
diff --git a/lib/filestorage/file_system_filedir.php b/lib/filestorage/file_system_filedir.php
@@ -393,7 +393,14 @@ public function add_file_from_path($pathname, $contenthash = null) {
             ignore_user_abort($prev);
             throw new file_exception('storedfilecannotcreatefile');
         }
-        rename($hashfile.'.tmp', $hashfile);
+        if (!rename($hashfile.'.tmp', $hashfile)) {
+            // Something very strange went wrong.
+            @unlink($hashfile . '.tmp');
+            // Note, we don't try to clean up $hashfile. Almost certainly, if it exists
+            // (e.g. written by another process?) it will be right, so don't wipe it.
+            ignore_user_abort($prev);
+            throw new file_exception('storedfilecannotcreatefile');
+        }
         chmod($hashfile, $this->filepermissions); // Fix permissions if needed.
         if (file_exists($hashfile.'.tmp')) {
             // Just in case anything fails in a weird way.
@@ -470,7 +477,14 @@ public function add_file_from_string($content) {
             ignore_user_abort($prev);
             throw new file_exception('storedfilecannotcreatefile');
         }
-        rename($hashfile.'.tmp', $hashfile);
+        if (!rename($hashfile.'.tmp', $hashfile)) {
+            // Something very strange went wrong.
+            @unlink($hashfile . '.tmp');
+            // Note, we don't try to clean up $hashfile. Almost certainly, if it exists
+            // (e.g. written by another process?) it will be right, so don't wipe it.
+            ignore_user_abort($prev);
+            throw new file_exception('storedfilecannotcreatefile');
+        }
         chmod($hashfile, $this->filepermissions); // Fix permissions if needed.
         if (file_exists($hashfile.'.tmp')) {
             // Just in case anything fails in a weird way.