From 8dd8b31cbbadd11bf88157f415cd5dc08b063043 Mon Sep 17 00:00:00 2001
From: Michiel Rook <mrook@php.net>
Date: Tue, 15 Sep 2020 14:04:49 +0200
Subject: [PATCH] Fixes #31 - don't try to copy username/groupname in chroot
 jail

---
 Archive/Tar.php | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/Archive/Tar.php b/Archive/Tar.php
index ab00e11..5a52ce8 100644
--- a/Archive/Tar.php
+++ b/Archive/Tar.php
@@ -1515,8 +1515,13 @@ public function _writeHeaderBlock(
             $userinfo = posix_getpwuid($p_uid);
             $groupinfo = posix_getgrgid($p_gid);
 
-            $v_uname = $userinfo['name'];
-            $v_gname = $groupinfo['name'];
+            if ($userinfo === false || $groupinfo === false) {
+                $v_uname = '';
+                $v_gname = '';
+            } else {
+                $v_uname = $userinfo['name'];
+                $v_gname = $groupinfo['name'];
+            }
         } else {
             $v_uname = '';
             $v_gname = '';