From fe1fd6120db6d03c1a580a21b32e059fbc93d7aa Mon Sep 17 00:00:00 2001
From: Remi Collet <remi@remirepo.net>
Date: Thu, 19 Mar 2020 17:31:17 +0100
Subject: [PATCH] Fix Bug #79296 ZipArchive::open fails on empty file

---
 ext/zip/php_zip.c           | 15 +++++++++++++++
 ext/zip/tests/bug53885.phpt |  1 -
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/ext/zip/php_zip.c b/ext/zip/php_zip.c
index f9a9a8d74f4e8..fb9d3aefec889 100644
--- a/ext/zip/php_zip.c
+++ b/ext/zip/php_zip.c
@@ -1487,6 +1487,21 @@ static ZIPARCHIVE_METHOD(open)
 		ze_obj->filename = NULL;
 	}
 
+#if LIBZIP_VERSION_MAJOR > 1 || LIBZIP_VERSION_MAJOR == 1 && LIBZIP_VERSION_MINOR >= 6
+	/* reduce BC break introduce in libzip 1.6.0
+	   "Do not accept empty files as valid zip archives any longer" */
+
+	/* open for write without option to empty the archive */
+	if ((flags & (ZIP_TRUNCATE | ZIP_RDONLY)) == 0) {
+		zend_stat_t st;
+
+		/* exists and is empty */
+		if (VCWD_STAT(resolved_path, &st) == 0 && st.st_size == 0) {
+			flags |= ZIP_TRUNCATE;
+		}
+	}
+#endif
+
 	intern = zip_open(resolved_path, flags, &err);
 	if (!intern || err) {
 		efree(resolved_path);
diff --git a/ext/zip/tests/bug53885.phpt b/ext/zip/tests/bug53885.phpt
index 75f6fe1609eaa..6f95a661b323b 100644
--- a/ext/zip/tests/bug53885.phpt
+++ b/ext/zip/tests/bug53885.phpt
@@ -3,7 +3,6 @@ Bug #53885 (ZipArchive segfault with FL_UNCHANGED on empty archive)
 --SKIPIF--
 <?php
 if(!extension_loaded('zip')) die('skip');
-if(version_compare(ZipArchive::LIBZIP_VERSION, '1.6', '>=')) die('skip libzip too recent');
 ?>
 --FILE--
 <?php