git.openwrt.org Git - feed/packages.git/blob

   1 From 79c6b602efc9a906c8496f3d5f4d54c54b48fa06 Mon Sep 17 00:00:00 2001
   2 From: "Miss Islington (bot)"
   3  <31488909+miss-islington@users.noreply.github.com>
   4 Date: Wed, 15 Jul 2020 05:35:08 -0700
   5 Subject: [PATCH] bpo-39017: Avoid infinite loop in the tarfile module
   6  (GH-21454) (GH-21484)
   7
   8 Avoid infinite loop when reading specially crafted TAR files using the tarfile module
   9 (CVE-2019-20907).
  10 (cherry picked from commit 5a8d121a1f3ef5ad7c105ee378cc79a3eac0c7d4)
  11
  12 Co-authored-by: Rishi <rishi_devan@mail.com>
  13 ---
  14  Lib/tarfile.py                                    |   2 ++
  15  Lib/test/recursion.tar                            | Bin 0 -> 516 bytes
  16  Lib/test/test_tarfile.py                          |   7 +++++++
  17  .../2020-07-12-22-16-58.bpo-39017.x3Cg-9.rst      |   1 +
  18  4 files changed, 10 insertions(+)
  19  create mode 100644 Lib/test/recursion.tar
  20  create mode 100644 Misc/NEWS.d/next/Library/2020-07-12-22-16-58.bpo-39017.x3Cg-9.rst
  21
  22 diff --git a/Lib/tarfile.py b/Lib/tarfile.py
  23 index 3b596cbf49d27..3be5188c8b0a2 100755
  24 --- a/Lib/tarfile.py
  25 +++ b/Lib/tarfile.py
  26 @@ -1233,6 +1233,8 @@ def _proc_pax(self, tarfile):
  27
  28              length, keyword = match.groups()
  29              length = int(length)
  30 +            if length == 0:
  31 +                raise InvalidHeaderError("invalid header")
  32              value = buf[match.end(2) + 1:match.start(1) + length - 1]
  33
  34              # Normally, we could just use "utf-8" as the encoding and "strict"
  35 diff --git a/Lib/test/test_tarfile.py b/Lib/test/test_tarfile.py
  36 index 5e4d75ecfce1a..9133d60e49be1 100644
  37 --- a/Lib/test/test_tarfile.py
  38 +++ b/Lib/test/test_tarfile.py
  39 @@ -395,6 +395,13 @@ def test_premature_end_of_archive(self):
  40                  with self.assertRaisesRegex(tarfile.ReadError, "unexpected end of data"):
  41                      tar.extractfile(t).read()
  42
  43 +    def test_length_zero_header(self):
  44 +        # bpo-39017 (CVE-2019-20907): reading a zero-length header should fail
  45 +        # with an exception
  46 +        with self.assertRaisesRegex(tarfile.ReadError, "file could not be opened successfully"):
  47 +            with tarfile.open(support.findfile('recursion.tar')) as tar:
  48 +                pass
  49 +
  50  class MiscReadTestBase(CommonReadTest):
  51      def requires_name_attribute(self):
  52          pass
  53 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
  54 new file mode 100644
  55 index 0000000000000..ad26676f8b856
  56 --- /dev/null
  57 +++ b/Misc/NEWS.d/next/Library/2020-07-12-22-16-58.bpo-39017.x3Cg-9.rst
  58 @@ -0,0 +1 @@
  59 +Avoid infinite loop when reading specially crafted TAR files using the tarfile module (CVE-2019-20907).