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From a06a6bf4e67a50561f6d6fb33534df1d3035ea34 Mon Sep 17 00:00:00 2001
From: Rishi <rishi_devan@mail.com>
Date: Wed, 15 Jul 2020 13:51:00 +0200
Subject: [PATCH] bpo-39017: Avoid infinite loop in the tarfile module
(GH-21454)
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>
Removed testing 'recursion.tar' tar file due to binary data
Upstream-Status: Backport [https://github.com/python/cpython/commit/c55479556db015f48fc8bbca17f64d3e65598559]
CVE: CVE-2019-20907
Signed-off-by: Andrej Valek <andrej.valek@siemens.com>
---
Lib/tarfile.py | 2 ++
.../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 d31b9cbb51d65..7a69e1b1aa544 100755
--- a/Lib/tarfile.py
+++ b/Lib/tarfile.py
@@ -1241,6 +1241,8 @@ def _proc_pax(self, tarfile):
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/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 0000000000000..ad26676f8b856
--- /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).
|
