From b099ce737f6e6cc9f3a1bf756af78eaa1c1480cd Mon Sep 17 00:00:00 2001 From: Rishi Date: Wed, 15 Jul 2020 13:51:00 +0200 Subject: [PATCH] 00351-cve-2019-20907-fix-infinite-loop-in-tarfile.patch 00351 # Avoid infinite loop when reading specially crafted TAR files using the tarfile module (CVE-2019-20907). See: https://bugs.python.org/issue39017 --- Lib/tarfile.py | 2 ++ Lib/test/recursion.tar | Bin 0 -> 516 bytes Lib/test/test_tarfile.py | 7 +++++++ .../2020-07-12-22-16-58.bpo-39017.x3Cg-9.rst | 1 + 4 files changed, 10 insertions(+) create mode 100644 Lib/test/recursion.tar create mode 100644 Misc/NEWS.d/next/Library/2020-07-12-22-16-58.bpo-39017.x3Cg-9.rst 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 new file mode 100644 index 0000000000000000000000000000000000000000..b8237251964983f54ed1966297e887636cd0c5f4 GIT binary patch literal 516 zcmYdFPRz+kEn=W0Fn}74P8%Xw3X=l~85kIuo0>8xq$A1Gm}!7)KUsFc41m#O8A5+e I1_}|j06>QaCIA2c literal 0 HcmV?d00001 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). -- 2.25.4