[Python-checkins] cpython (2.7): Issue #9720: zipfile now writes correct local headers for files larger than 4

Mon Jan 14 23:45:10 CET 2013

http://hg.python.org/cpython/rev/ce869b05762c
changeset: 81501:ce869b05762c
branch: 2.7
parent: 81491:c5451d4a0cdd
user: Serhiy Storchaka <storchaka at gmail.com>
date: Tue Jan 15 00:29:51 2013 +0200
summary:
 Issue #9720: zipfile now writes correct local headers for files larger than 4 GiB.
files:
 Lib/zipfile.py | 47 +++++++++++++++++++++++++------------
 Misc/NEWS | 3 ++
 2 files changed, 35 insertions(+), 15 deletions(-)

diff --git a/Lib/zipfile.py b/Lib/zipfile.py
--- a/Lib/zipfile.py
+++ b/Lib/zipfile.py
@@ -316,7 +316,7 @@
 # compress_size Size of the compressed file
 # file_size Size of the uncompressed file
 
- def FileHeader(self):
+ def FileHeader(self, zip64=None):
 """Return the per-file header as a string."""
 dt = self.date_time
 dosdate = (dt[0] - 1980) << 9 | dt[1] << 5 | dt[2]
@@ -331,12 +331,17 @@
 
 extra = self.extra
 
- if file_size > ZIP64_LIMIT or compress_size > ZIP64_LIMIT:
- # File is larger than what fits into a 4 byte integer,
- # fall back to the ZIP64 extension
+ if zip64 is None:
+ zip64 = file_size > ZIP64_LIMIT or compress_size > ZIP64_LIMIT
+ if zip64:
 fmt = '<HHQQ'
 extra = extra + struct.pack(fmt,
 1, struct.calcsize(fmt)-4, file_size, compress_size)
+ if file_size > ZIP64_LIMIT or compress_size > ZIP64_LIMIT:
+ if not zip64:
+ raise LargeZipFile("Filesize would require ZIP64 extensions")
+ # File is larger than what fits into a 4 byte integer,
+ # fall back to the ZIP64 extension
 file_size = 0xffffffff
 compress_size = 0xffffffff
 self.extract_version = max(45, self.extract_version)
@@ -1113,20 +1118,23 @@
 zinfo.CRC = 0
 self.filelist.append(zinfo)
 self.NameToInfo[zinfo.filename] = zinfo
- self.fp.write(zinfo.FileHeader())
+ self.fp.write(zinfo.FileHeader(False))
 return
 
 with open(filename, "rb") as fp:
 # Must overwrite CRC and sizes with correct data later
 zinfo.CRC = CRC = 0
 zinfo.compress_size = compress_size = 0
- zinfo.file_size = file_size = 0
- self.fp.write(zinfo.FileHeader())
+ # Compressed size can be larger than uncompressed size
+ zip64 = self._allowZip64 and \
+ zinfo.file_size * 1.05 > ZIP64_LIMIT
+ self.fp.write(zinfo.FileHeader(zip64))
 if zinfo.compress_type == ZIP_DEFLATED:
 cmpr = zlib.compressobj(zlib.Z_DEFAULT_COMPRESSION,
 zlib.DEFLATED, -15)
 else:
 cmpr = None
+ file_size = 0
 while 1:
 buf = fp.read(1024 * 8)
 if not buf:
@@ -1146,11 +1154,16 @@
 zinfo.compress_size = file_size
 zinfo.CRC = CRC
 zinfo.file_size = file_size
- # Seek backwards and write CRC and file sizes
+ if not zip64 and self._allowZip64:
+ if file_size > ZIP64_LIMIT:
+ raise RuntimeError('File size has increased during compressing')
+ if compress_size > ZIP64_LIMIT:
+ raise RuntimeError('Compressed size larger than uncompressed size')
+ # Seek backwards and write file header (which will now include
+ # correct CRC and file sizes)
 position = self.fp.tell() # Preserve current position in file
- self.fp.seek(zinfo.header_offset + 14, 0)
- self.fp.write(struct.pack("<LLL", zinfo.CRC, zinfo.compress_size,
- zinfo.file_size))
+ self.fp.seek(zinfo.header_offset, 0)
+ self.fp.write(zinfo.FileHeader(zip64))
 self.fp.seek(position, 0)
 self.filelist.append(zinfo)
 self.NameToInfo[zinfo.filename] = zinfo
@@ -1187,14 +1200,18 @@
 zinfo.compress_size = len(bytes) # Compressed size
 else:
 zinfo.compress_size = zinfo.file_size
- zinfo.header_offset = self.fp.tell() # Start of header bytes
- self.fp.write(zinfo.FileHeader())
+ zip64 = zinfo.file_size > ZIP64_LIMIT or \
+ zinfo.compress_size > ZIP64_LIMIT
+ if zip64 and not self._allowZip64:
+ raise LargeZipFile("Filesize would require ZIP64 extensions")
+ self.fp.write(zinfo.FileHeader(zip64))
 self.fp.write(bytes)
- self.fp.flush()
 if zinfo.flag_bits & 0x08:
 # Write CRC and file sizes after the file data
- self.fp.write(struct.pack("<LLL", zinfo.CRC, zinfo.compress_size,
+ fmt = '<LQQ' if zip64 else '<LLL'
+ self.fp.write(struct.pack(fmt, zinfo.CRC, zinfo.compress_size,
 zinfo.file_size))
+ self.fp.flush()
 self.filelist.append(zinfo)
 self.NameToInfo[zinfo.filename] = zinfo
 
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -186,6 +186,9 @@
 Library
 -------
 
+- Issue #9720: zipfile now writes correct local headers for files larger than
+ 4 GiB.
+
 - Issue #16829: IDLE printing no longer fails if there are spaces or other
 special characters in the file path.
 
-- 
Repository URL: http://hg.python.org/cpython
