From feccdb2a249a71be330765be77dee57121866779 Mon Sep 17 00:00:00 2001
From: Serhiy Storchaka <storchaka@gmail.com>
Date: Thu, 9 Mar 2017 18:34:03 +0200
Subject: bpo-29774: Improve error reporting for corrupted extra field in ZIP
 file. (#583)

---
 Lib/zipfile.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Lib/zipfile.py b/Lib/zipfile.py
index b5c16db..8a19ca2 100644
--- a/Lib/zipfile.py
+++ b/Lib/zipfile.py
@@ -438,7 +438,9 @@ class ZipInfo (object):
         unpack = struct.unpack
         while len(extra) >= 4:
             tp, ln = unpack('<HH', extra[:4])
-            if tp == 1:
+            if ln+4 > len(extra):
+                raise BadZipFile("Corrupt extra field %04x (size=%d)" % (tp, ln))
+            if tp == 0x0001:
                 if ln >= 24:
                     counts = unpack('<QQQ', extra[4:28])
                 elif ln == 16:
-- 
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