ZP-845 Improve Utils::FixFileOwner.

Released under the Affero GNU General Public License (AGPL) version 3.

If we are running as root (bad idea), parent directory is owned by root,
and the file is owned by root, it means that we can't FixFileOwner,
so remove the file and throw an exception instead of silently breaking zpush
Signed-off-by: Etienne CHAMPETIER <champetier.etienne@gmail.com>

src/lib/utils/utils.php

@@ -886,11 +886,16 @@ class Utils {
         if(posix_getuid() == 0 && file_exists($file)) {
             $dir = dirname($file);
             $perm_dir = stat($dir);
-            $perm_log = stat($file);
+            $perm_file = stat($file);
 
-            if($perm_dir[4] !== $perm_log[4] || $perm_dir[5] !== $perm_log[5]) {
-                chown($file, $perm_dir[4]);
-                chgrp($file, $perm_dir[5]);
+            if ($perm_file['uid'] == 0 && $perm_dir['uid'] == 0) {
+                unlink($file);
+                throw new FatalException("FixFileOwner: $dir must be owned by the nginx/apache/php user instead of root");
+            }
+
+            if($perm_dir['uid'] !== $perm_file['uid'] || $perm_dir['gid'] !== $perm_file['gid']) {
+                chown($file, $perm_dir['uid']);
+                chgrp($file, $perm_dir['gid']);
             }
         }
         return true;