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author | Rishi <rishi_devan@mail.com> | 2020-07-15 13:51:00 +0200 |
---|---|---|
committer | Petr Viktorin <pviktori@redhat.com> | 2020-07-15 17:28:12 +0200 |
commit | bde4372aa1f39803f5c33f1415e88b000d403d00 (patch) | |
tree | 9532089be9064f42f8e6a4a22bcac186fe8c3445 | |
parent | f52bf62fe12d46267e958f80dbe1f4425b55cd0f (diff) | |
download | cpython-git-backport-5a8d121-3.5.tar.gz |
[3.5] bpo-39017: Avoid infinite loop in the tarfile module (GH-21454)backport-5a8d121-3.5
Avoid infinite loop when reading specially crafted TAR files using the tarfile module
(CVE-2019-20907).
(cherry picked from commit 5a8d121a1f3ef5ad7c105ee378cc79a3eac0c7d4)
Co-authored-by: Rishi <rishi_devan@mail.com>
-rwxr-xr-x | 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 999a99b978..8015fae7a6 100755 --- a/Lib/tarfile.py +++ b/Lib/tarfile.py @@ -1221,6 +1221,8 @@ 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] # Normally, we could just use "utf-8" as the encoding and "strict" diff --git a/Lib/test/recursion.tar b/Lib/test/recursion.tar Binary files differnew file mode 100644 index 0000000000..b823725196 --- /dev/null +++ b/Lib/test/recursion.tar diff --git a/Lib/test/test_tarfile.py b/Lib/test/test_tarfile.py index 1efb841bb2..2438fd3abf 100644 --- a/Lib/test/test_tarfile.py +++ b/Lib/test/test_tarfile.py @@ -394,6 +394,13 @@ class CommonReadTest(ReadTest): with self.assertRaisesRegex(tarfile.ReadError, "unexpected end of data"): tar.extractfile(t).read() + def test_length_zero_header(self): + # bpo-39017 (CVE-2019-20907): reading a zero-length header should fail + # with an exception + with self.assertRaisesRegex(tarfile.ReadError, "file could not be opened successfully"): + with tarfile.open(support.findfile('recursion.tar')) as tar: + pass + class MiscReadTestBase(CommonReadTest): def requires_name_attribute(self): pass 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 0000000000..ad26676f8b --- /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). |