Merge with 3.5: Issue #24259: tarfile now raises a ReadError if an archive is truncated inside a data segment.

This commit is contained in:
Lars Gustäbel 2015-07-06 09:32:05 +02:00
commit 7afe40e40e
3 changed files with 41 additions and 7 deletions

View File

@ -225,7 +225,7 @@ def calc_chksums(buf):
signed_chksum = 256 + sum(struct.unpack_from("148b8x356b", buf))
return unsigned_chksum, signed_chksum
def copyfileobj(src, dst, length=None):
def copyfileobj(src, dst, length=None, exception=OSError):
"""Copy length bytes from fileobj src to fileobj dst.
If length is None, copy the entire content.
"""
@ -240,13 +240,13 @@ def copyfileobj(src, dst, length=None):
for b in range(blocks):
buf = src.read(BUFSIZE)
if len(buf) < BUFSIZE:
raise OSError("end of file reached")
raise exception("unexpected end of data")
dst.write(buf)
if remainder != 0:
buf = src.read(remainder)
if len(buf) < remainder:
raise OSError("end of file reached")
raise exception("unexpected end of data")
dst.write(buf)
return
@ -690,7 +690,10 @@ class _FileInFile(object):
length = min(size, stop - self.position)
if data:
self.fileobj.seek(offset + (self.position - start))
buf += self.fileobj.read(length)
b = self.fileobj.read(length)
if len(b) != length:
raise ReadError("unexpected end of data")
buf += b
else:
buf += NUL * length
size -= length
@ -2150,9 +2153,9 @@ class TarFile(object):
if tarinfo.sparse is not None:
for offset, size in tarinfo.sparse:
target.seek(offset)
copyfileobj(source, target, size)
copyfileobj(source, target, size, ReadError)
else:
copyfileobj(source, target, tarinfo.size)
copyfileobj(source, target, tarinfo.size, ReadError)
target.seek(tarinfo.size)
target.truncate()
@ -2267,8 +2270,13 @@ class TarFile(object):
self.firstmember = None
return m
# Advance the file pointer.
if self.offset != self.fileobj.tell():
self.fileobj.seek(self.offset - 1)
if not self.fileobj.read(1):
raise ReadError("unexpected end of data")
# Read the next block.
self.fileobj.seek(self.offset)
tarinfo = None
while True:
try:

View File

@ -364,6 +364,29 @@ class CommonReadTest(ReadTest):
finally:
tar.close()
def test_premature_end_of_archive(self):
for size in (512, 600, 1024, 1200):
with tarfile.open(tmpname, "w:") as tar:
t = tarfile.TarInfo("foo")
t.size = 1024
tar.addfile(t, io.BytesIO(b"a" * 1024))
with open(tmpname, "r+b") as fobj:
fobj.truncate(size)
with tarfile.open(tmpname) as tar:
with self.assertRaisesRegex(tarfile.ReadError, "unexpected end of data"):
for t in tar:
pass
with tarfile.open(tmpname) as tar:
t = tar.next()
with self.assertRaisesRegex(tarfile.ReadError, "unexpected end of data"):
tar.extract(t, TEMPDIR)
with self.assertRaisesRegex(tarfile.ReadError, "unexpected end of data"):
tar.extractfile(t).read()
class MiscReadTestBase(CommonReadTest):
def requires_name_attribute(self):

View File

@ -33,6 +33,9 @@ Core and Builtins
Library
-------
- Issue #24259: tarfile now raises a ReadError if an archive is truncated
inside a data segment.
What's New in Python 3.5.0 beta 3?
==================================