mirror of
https://github.com/python/cpython.git
synced 2025-10-21 14:12:27 +00:00
Issue #1159051: Back out a fix for handling corrupted gzip files that
broke backwards compatibility.
This commit is contained in:
Georg Brandl
parent
a9217a42e6
commit
93b061bc3e
4 changed files with 41 additions and 68 deletions
73
Lib/gzip.py
73
Lib/gzip.py
|
|
@ -33,6 +33,9 @@ def write32u(output, value):
|
|||
# or unsigned.
|
||||
output.write(struct.pack("<L", value))
|
||||
|
||||
def read32(input):
|
||||
return struct.unpack("<I", input.read(4))[0]
|
||||
|
||||
def open(filename, mode="rb", compresslevel=9):
|
||||
"""Shorthand for GzipFile(filename, mode, compresslevel).
|
||||
|
||||
|
|
@ -256,32 +259,27 @@ class GzipFile(io.BufferedIOBase):
|
|||
self.crc = zlib.crc32(b"") & 0xffffffff
|
||||
self.size = 0
|
||||
|
||||
def _read_exact(self, n):
|
||||
data = self.fileobj.read(n)
|
||||
while len(data) < n:
|
||||
b = self.fileobj.read(n - len(data))
|
||||
if not b:
|
||||
raise EOFError("Compressed file ended before the "
|
||||
"end-of-stream marker was reached")
|
||||
data += b
|
||||
return data
|
||||
|
||||
def _read_gzip_header(self):
|
||||
magic = self.fileobj.read(2)
|
||||
if magic == b'':
|
||||
return False
|
||||
raise EOFError("Reached EOF")
|
||||
|
||||
if magic != b'\037\213':
|
||||
raise IOError('Not a gzipped file')
|
||||
|
||||
method, flag, self.mtime = struct.unpack("<BBIxx", self._read_exact(8))
|
||||
method = ord( self.fileobj.read(1) )
|
||||
if method != 8:
|
||||
raise IOError('Unknown compression method')
|
||||
flag = ord( self.fileobj.read(1) )
|
||||
self.mtime = read32(self.fileobj)
|
||||
# extraflag = self.fileobj.read(1)
|
||||
# os = self.fileobj.read(1)
|
||||
self.fileobj.read(2)
|
||||
|
||||
if flag & FEXTRA:
|
||||
# Read & discard the extra field, if present
|
||||
extra_len, = struct.unpack("<H", self._read_exact(2))
|
||||
self._read_exact(extra_len)
|
||||
xlen = ord(self.fileobj.read(1))
|
||||
xlen = xlen + 256*ord(self.fileobj.read(1))
|
||||
self.fileobj.read(xlen)
|
||||
if flag & FNAME:
|
||||
# Read and discard a null-terminated string containing the filename
|
||||
while True:
|
||||
|
|
@ -295,13 +293,12 @@ class GzipFile(io.BufferedIOBase):
|
|||
if not s or s==b'\000':
|
||||
break
|
||||
if flag & FHCRC:
|
||||
self._read_exact(2) # Read & discard the 16-bit header CRC
|
||||
self.fileobj.read(2) # Read & discard the 16-bit header CRC
|
||||
|
||||
unused = self.fileobj.unused()
|
||||
if unused:
|
||||
uncompress = self.decompress.decompress(unused)
|
||||
self._add_read_data(uncompress)
|
||||
return True
|
||||
|
||||
def write(self,data):
|
||||
self._check_closed()
|
||||
|
|
@ -335,16 +332,20 @@ class GzipFile(io.BufferedIOBase):
|
|||
|
||||
readsize = 1024
|
||||
if size < 0: # get the whole thing
|
||||
while self._read(readsize):
|
||||
readsize = min(self.max_read_chunk, readsize * 2)
|
||||
size = self.extrasize
|
||||
try:
|
||||
while True:
|
||||
self._read(readsize)
|
||||
readsize = min(self.max_read_chunk, readsize * 2)
|
||||
except EOFError:
|
||||
size = self.extrasize
|
||||
else: # just get some more of it
|
||||
while size > self.extrasize:
|
||||
if not self._read(readsize):
|
||||
if size > self.extrasize:
|
||||
size = self.extrasize
|
||||
break
|
||||
readsize = min(self.max_read_chunk, readsize * 2)
|
||||
try:
|
||||
while size > self.extrasize:
|
||||
self._read(readsize)
|
||||
readsize = min(self.max_read_chunk, readsize * 2)
|
||||
except EOFError:
|
||||
if size > self.extrasize:
|
||||
size = self.extrasize
|
||||
|
||||
offset = self.offset - self.extrastart
|
||||
chunk = self.extrabuf[offset: offset + size]
|
||||
|
|
@ -365,9 +366,12 @@ class GzipFile(io.BufferedIOBase):
|
|||
if self.extrasize == 0:
|
||||
if self.fileobj is None:
|
||||
return b''
|
||||
# Ensure that we don't return b"" if we haven't reached EOF.
|
||||
# 1024 is the same buffering heuristic used in read()
|
||||
while self.extrasize == 0 and self._read(max(n, 1024)):
|
||||
try:
|
||||
# Ensure that we don't return b"" if we haven't reached EOF.
|
||||
while self.extrasize == 0:
|
||||
# 1024 is the same buffering heuristic used in read()
|
||||
self._read(max(n, 1024))
|
||||
except EOFError:
|
||||
pass
|
||||
offset = self.offset - self.extrastart
|
||||
remaining = self.extrasize
|
||||
|
|
@ -380,14 +384,13 @@ class GzipFile(io.BufferedIOBase):
|
|||
|
||||
def _read(self, size=1024):
|
||||
if self.fileobj is None:
|
||||
return False
|
||||
raise EOFError("Reached EOF")
|
||||
|
||||
if self._new_member:
|
||||
# If the _new_member flag is set, we have to
|
||||
# jump to the next member, if there is one.
|
||||
self._init_read()
|
||||
if not self._read_gzip_header():
|
||||
return False
|
||||
self._read_gzip_header()
|
||||
self.decompress = zlib.decompressobj(-zlib.MAX_WBITS)
|
||||
self._new_member = False
|
||||
|
||||
|
|
@ -404,7 +407,7 @@ class GzipFile(io.BufferedIOBase):
|
|||
self.fileobj.prepend(self.decompress.unused_data, True)
|
||||
self._read_eof()
|
||||
self._add_read_data( uncompress )
|
||||
return False
|
||||
raise EOFError('Reached EOF')
|
||||
|
||||
uncompress = self.decompress.decompress(buf)
|
||||
self._add_read_data( uncompress )
|
||||
|
|
@ -420,7 +423,6 @@ class GzipFile(io.BufferedIOBase):
|
|||
# a new member on the next call
|
||||
self._read_eof()
|
||||
self._new_member = True
|
||||
return True
|
||||
|
||||
def _add_read_data(self, data):
|
||||
self.crc = zlib.crc32(data, self.crc) & 0xffffffff
|
||||
|
|
@ -435,7 +437,8 @@ class GzipFile(io.BufferedIOBase):
|
|||
# We check the that the computed CRC and size of the
|
||||
# uncompressed data matches the stored values. Note that the size
|
||||
# stored is the true file size mod 2**32.
|
||||
crc32, isize = struct.unpack("<II", self._read_exact(8))
|
||||
crc32 = read32(self.fileobj)
|
||||
isize = read32(self.fileobj) # may exceed 2GB
|
||||
if crc32 != self.crc:
|
||||
raise IOError("CRC check failed %s != %s" % (hex(crc32),
|
||||
hex(self.crc)))
|
||||
|
|
|
|||
|
|
@ -292,24 +292,6 @@ class BZ2FileTest(BaseTest):
|
|||
self.assertRaises(ValueError, f.readline)
|
||||
self.assertRaises(ValueError, f.readlines)
|
||||
|
||||
def test_read_truncated(self):
|
||||
# Drop the eos_magic field (6 bytes) and CRC (4 bytes).
|
||||
truncated = self.DATA[:-10]
|
||||
with open(self.filename, 'wb') as f:
|
||||
f.write(truncated)
|
||||
with BZ2File(self.filename) as f:
|
||||
self.assertRaises(EOFError, f.read)
|
||||
with BZ2File(self.filename) as f:
|
||||
self.assertEqual(f.read(len(self.TEXT)), self.TEXT)
|
||||
self.assertRaises(EOFError, f.read, 1)
|
||||
# Incomplete 4-byte file header, and block header of at least 146 bits.
|
||||
for i in range(22):
|
||||
with open(self.filename, 'wb') as f:
|
||||
f.write(truncated[:i])
|
||||
with BZ2File(self.filename) as f:
|
||||
self.assertRaises(EOFError, f.read, 1)
|
||||
|
||||
|
||||
class BZ2CompressorTest(BaseTest):
|
||||
def testCompress(self):
|
||||
# "Test BZ2Compressor.compress()/flush()"
|
||||
|
|
|
|||
13
Lib/test/test_gzip.py
Normal file → Executable file
13
Lib/test/test_gzip.py
Normal file → Executable file
|
|
@ -365,19 +365,6 @@ class TestGzip(unittest.TestCase):
|
|||
datac = gzip.compress(data)
|
||||
self.assertEqual(gzip.decompress(datac), data)
|
||||
|
||||
def test_read_truncated(self):
|
||||
data = data1*50
|
||||
# Drop the CRC (4 bytes) and file size (4 bytes).
|
||||
truncated = gzip.compress(data)[:-8]
|
||||
with gzip.GzipFile(fileobj=io.BytesIO(truncated)) as f:
|
||||
self.assertRaises(EOFError, f.read)
|
||||
with gzip.GzipFile(fileobj=io.BytesIO(truncated)) as f:
|
||||
self.assertEqual(f.read(len(data)), data)
|
||||
self.assertRaises(EOFError, f.read, 1)
|
||||
# Incomplete 10-byte header.
|
||||
for i in range(2, 10):
|
||||
with gzip.GzipFile(fileobj=io.BytesIO(truncated[:i])) as f:
|
||||
self.assertRaises(EOFError, f.read, 1)
|
||||
|
||||
def test_read_with_extra(self):
|
||||
# Gzip data with an extra field
|
||||
|
|
|
|||
|
|
@ -14,11 +14,12 @@ Library
|
|||
which were omitted in 3.2.4 when updating the bundled version of
|
||||
libffi used by ctypes.
|
||||
|
||||
- Issue #17666: Fix reading gzip files with an extra field.
|
||||
|
||||
- Issue #15535: Fix namedtuple pickles which were picking up the OrderedDict
|
||||
instead of just the underlying tuple.
|
||||
|
||||
- Issue #1159051: Back out a fix for handling corrupted gzip files that
|
||||
broke backwards compatibility.
|
||||
|
||||
Build
|
||||
-----
|
||||
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue