bpo-34341: Fix appending to ZIP archives with the ZIP64 extension. (GH-8683)
diff --git a/Lib/zipfile.py b/Lib/zipfile.py
index 7f23778..89df90b 100644
--- a/Lib/zipfile.py
+++ b/Lib/zipfile.py
@@ -159,6 +159,27 @@
_CD64_DIRECTORY_SIZE = 8
_CD64_OFFSET_START_CENTDIR = 9
+_EXTRA_FIELD_STRUCT = struct.Struct('<HH')
+
+def _strip_extra(extra, xids):
+ # Remove Extra Fields with specified IDs.
+ unpack = _EXTRA_FIELD_STRUCT.unpack
+ modified = False
+ buffer = []
+ start = i = 0
+ while i + 4 <= len(extra):
+ xid, xlen = unpack(extra[i : i + 4])
+ j = i + 4 + xlen
+ if xid in xids:
+ if i != start:
+ buffer.append(extra[start : i])
+ start = j
+ modified = True
+ i = j
+ if not modified:
+ return extra
+ return b''.join(buffer)
+
def _check_zipfile(fp):
try:
if _EndRecData(fp):
@@ -1819,6 +1840,7 @@
min_version = 0
if extra:
# Append a ZIP64 field to the extra's
+ extra_data = _strip_extra(extra_data, (1,))
extra_data = struct.pack(
'<HH' + 'Q'*len(extra),
1, 8*len(extra), *extra) + extra_data