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Issue #4844: ZipFile now raises BadZipfile when opens a ZIP file with an

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incomplete "End of Central Directory" record.  Original patch by Guilherme
Polo and Alan McIntyre.
This commit is contained in:
Serhiy Storchaka 2013-01-31 15:26:55 +02:00
parent 18fae3f954
commit 0be506a5ba
3 changed files with 38 additions and 7 deletions
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27
Lib/zipfile.py
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@ -166,6 +166,8 @@ def _EndRecData64(fpin, offset, endrec):
return endrec
data = fpin.read(sizeEndCentDir64Locator)
if len(data) != sizeEndCentDir64Locator:
return endrec
sig, diskno, reloff, disks = struct.unpack(structEndArchive64Locator, data)
if sig != stringEndArchive64Locator:
return endrec
@ -176,6 +178,8 @@ def _EndRecData64(fpin, offset, endrec):
# Assume no 'zip64 extensible data'
fpin.seek(offset - sizeEndCentDir64Locator - sizeEndCentDir64, 2)
data = fpin.read(sizeEndCentDir64)
if len(data) != sizeEndCentDir64:
return endrec
sig, sz, create_version, read_version, disk_num, disk_dir, \
dircount, dircount2, dirsize, diroffset = \
struct.unpack(structEndArchive64, data)
@ -211,7 +215,9 @@ def _EndRecData(fpin):
except IOError:
return None
data = fpin.read()
if data[0:4] == stringEndArchive and data[-2:] == "\000\000":
if (len(data) == sizeEndCentDir and
data[0:4] == stringEndArchive and
data[-2:] == b"\000\000"):
# the signature is correct and there's no comment, unpack structure
endrec = struct.unpack(structEndArchive, data)
endrec=list(endrec)
@ -235,6 +241,9 @@ def _EndRecData(fpin):
if start >= 0:
# found the magic number; attempt to unpack and interpret
recData = data[start:start+sizeEndCentDir]
if len(recData) != sizeEndCentDir:
# Zip file is corrupted.
return None
endrec = list(struct.unpack(structEndArchive, recData))
commentSize = endrec[_ECD_COMMENT_SIZE] #as claimed by the zip file
comment = data[start+sizeEndCentDir:start+sizeEndCentDir+commentSize]
@ -246,7 +255,7 @@ def _EndRecData(fpin):
endrec)
# Unable to find a valid end of central directory structure
return
return None
class ZipInfo (object):
@ -818,9 +827,11 @@ class ZipFile(object):
total = 0
while total < size_cd:
centdir = fp.read(sizeCentralDir)
if centdir[0:4] != stringCentralDir:
raise BadZipfile, "Bad magic number for central directory"
if len(centdir) != sizeCentralDir:
raise BadZipfile("Truncated central directory")
centdir = struct.unpack(structCentralDir, centdir)
if centdir[_CD_SIGNATURE] != stringCentralDir:
raise BadZipfile("Bad magic number for central directory")
if self.debug > 2:
print centdir
filename = fp.read(centdir[_CD_FILENAME_LENGTH])
@ -948,10 +959,12 @@ class ZipFile(object):
# Skip the file header:
fheader = zef_file.read(sizeFileHeader)
if fheader[0:4] != stringFileHeader:
raise BadZipfile, "Bad magic number for file header"
if len(fheader) != sizeFileHeader:
raise BadZipfile("Truncated file header")
fheader = struct.unpack(structFileHeader, fheader)
if fheader[_FH_SIGNATURE] != stringFileHeader:
raise BadZipfile("Bad magic number for file header")
fname = zef_file.read(fheader[_FH_FILENAME_LENGTH])
if fheader[_FH_EXTRA_FIELD_LENGTH]:
zef_file.read(fheader[_FH_EXTRA_FIELD_LENGTH])