diff options
| -rw-r--r-- | Lib/tarfile.py | 2 | ||||
| -rw-r--r-- | Lib/test/recursion.tar | bin | 0 -> 516 bytes | |||
| -rw-r--r-- | Lib/test/test_tarfile.py | 7 | ||||
| -rw-r--r-- | Misc/NEWS.d/next/Library/2020-07-12-22-16-58.bpo-39017.x3Cg-9.rst | 1 |
4 files changed, 10 insertions, 0 deletions
diff --git a/Lib/tarfile.py b/Lib/tarfile.py index adf91d5..574a6bb 100644 --- a/Lib/tarfile.py +++ b/Lib/tarfile.py @@ -1400,6 +1400,8 @@ class TarInfo(object): length, keyword = match.groups() length = int(length) + if length == 0: + raise InvalidHeaderError("invalid header") value = buf[match.end(2) + 1:match.start(1) + length - 1] keyword = keyword.decode("utf8") diff --git a/Lib/test/recursion.tar b/Lib/test/recursion.tar Binary files differnew file mode 100644 index 0000000..b823725 --- /dev/null +++ b/Lib/test/recursion.tar diff --git a/Lib/test/test_tarfile.py b/Lib/test/test_tarfile.py index 89bd738..4592156 100644 --- a/Lib/test/test_tarfile.py +++ b/Lib/test/test_tarfile.py @@ -325,6 +325,13 @@ class CommonReadTest(ReadTest): class MiscReadTest(CommonReadTest): taropen = tarfile.TarFile.taropen + def test_length_zero_header(self): + # bpo-39017 (CVE-2019-20907): reading a zero-length header should fail + # with an exception + with self.assertRaisesRegexp(tarfile.ReadError, "file could not be opened successfully"): + with tarfile.open(support.findfile('recursion.tar')) as tar: + pass + def test_no_name_argument(self): with open(self.tarname, "rb") as fobj: tar = tarfile.open(fileobj=fobj, mode=self.mode) diff --git a/Misc/NEWS.d/next/Library/2020-07-12-22-16-58.bpo-39017.x3Cg-9.rst b/Misc/NEWS.d/next/Library/2020-07-12-22-16-58.bpo-39017.x3Cg-9.rst new file mode 100644 index 0000000..ad26676 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2020-07-12-22-16-58.bpo-39017.x3Cg-9.rst @@ -0,0 +1 @@ +Avoid infinite loop when reading specially crafted TAR files using the tarfile module (CVE-2019-20907). |