Issue #24259: tarfile now raises a ReadError if an archive is truncated inside a data segment.
diff --git a/Lib/tarfile.py b/Lib/tarfile.py
index d7c1500..66e5393 100644
--- a/Lib/tarfile.py
+++ b/Lib/tarfile.py
@@ -744,12 +744,18 @@
else:
return self.readsparse(size)
+ def __read(self, size):
+ buf = self.fileobj.read(size)
+ if len(buf) != size:
+ raise ReadError("unexpected end of data")
+ return buf
+
def readnormal(self, size):
"""Read operation for regular files.
"""
self.fileobj.seek(self.offset + self.position)
self.position += size
- return self.fileobj.read(size)
+ return self.__read(size)
def readsparse(self, size):
"""Read operation for sparse files.
@@ -777,7 +783,7 @@
realpos = section.realpos + self.position - section.offset
self.fileobj.seek(self.offset + realpos)
self.position += size
- return self.fileobj.read(size)
+ return self.__read(size)
else:
self.position += size
return NUL * size
@@ -2336,8 +2342,13 @@
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:
diff --git a/Lib/test/test_tarfile.py b/Lib/test/test_tarfile.py
index a92d371..a72c37b 100644
--- a/Lib/test/test_tarfile.py
+++ b/Lib/test/test_tarfile.py
@@ -285,6 +285,30 @@
"ignore_zeros=True should have skipped the %r-blocks" % char)
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, StringIO.StringIO("a" * 1024))
+
+ with open(tmpname, "r+b") as fobj:
+ fobj.truncate(size)
+
+ with tarfile.open(tmpname) as tar:
+ with self.assertRaisesRegexp(tarfile.ReadError, "unexpected end of data"):
+ for t in tar:
+ pass
+
+ with tarfile.open(tmpname) as tar:
+ t = tar.next()
+
+ with self.assertRaisesRegexp(tarfile.ReadError, "unexpected end of data"):
+ tar.extract(t, TEMPDIR)
+
+ with self.assertRaisesRegexp(tarfile.ReadError, "unexpected end of data"):
+ tar.extractfile(t).read()
+
class MiscReadTest(CommonReadTest):
taropen = tarfile.TarFile.taropen