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author | Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com> | 2020-07-15 05:36:36 -0700 |
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committer | GitHub <noreply@github.com> | 2020-07-15 08:36:36 -0400 |
commit | 47a2955589bdb1a114d271496ff803ad73f954b8 (patch) | |
tree | 492a366db38b167508a6d30510ad17c73fb0e467 | |
parent | bpo-41288: Fix a crash in unpickling invalid NEWOBJ_EX. (GH-21458) (GH-21462) (diff) | |
download | cpython-47a2955589bdb1a114d271496ff803ad73f954b8.tar.gz cpython-47a2955589bdb1a114d271496ff803ad73f954b8.tar.bz2 cpython-47a2955589bdb1a114d271496ff803ad73f954b8.zip |
bpo-39017: Avoid infinite loop in the tarfile module (GH-21454) (#21485)
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 62d22150f50..2ea47978ff6 100755 --- a/Lib/tarfile.py +++ b/Lib/tarfile.py @@ -1231,6 +1231,8 @@ 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 00000000000..b8237251964 --- /dev/null +++ b/Lib/test/recursion.tar diff --git a/Lib/test/test_tarfile.py b/Lib/test/test_tarfile.py index 4cd7d5370f5..573be812eaa 100644 --- a/Lib/test/test_tarfile.py +++ b/Lib/test/test_tarfile.py @@ -395,6 +395,13 @@ 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 00000000000..ad26676f8b8 --- /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). |