Buffer overflow in the _sha3 module in python versions <= 3.10 #98517

botovq · 2022-10-21T12:51:55Z

CVE-2022-37454 affects Python versions prior to 3.11. The fix discussed in XKCP's advisory can be adapted to these versions. The discoverer's writeup contains code that might be turned into regression tests.

Python 3.11 and later switched to using tiny_sha3 in GH-32060, so they should not be affected.

Tasks

This is a port of the applicable part of XKCP's fix [1] for CVE-2022-37454 and avoids the segmentation fault and the infinite loop in the test cases published in [2]. [1]: XKCP/XKCP@fdc6fef [2]: https://mouha.be/sha-3-buffer-overflow/

gpshead · 2022-10-21T18:42:05Z

Scope: When Python is linked against OpenSSL 1.1.1 or later, which is true on many modern systems, the OpenSSL provided sha3 implementation will be used instead of the vulnerable bundled _sha3 XKCP module code.

You can tell if your Python 3.10 or earlier is vulnerable by doing the following:

A potentially vulnerable Python if unpatched looks like this:

>>> import hashlib
>>> hashlib.sha3_224
<class '_sha3.sha3_224'>

A non-vulnerable Python looks like this:

>>> import hashlib
>>> hashlib.sha3_224
<built-in function openssl_sha3_224>

This is a port of the applicable part of XKCP's fix [1] for CVE-2022-37454 and avoids the segmentation fault and the infinite loop in the test cases published in [2]. [1]: XKCP/XKCP@fdc6fef [2]: https://mouha.be/sha-3-buffer-overflow/ Regression test added by: Gregory P. Smith [Google LLC] <greg@krypto.org>

…-98519) This is a port of the applicable part of XKCP's fix [1] for CVE-2022-37454 and avoids the segmentation fault and the infinite loop in the test cases published in [2]. [1]: XKCP/XKCP@fdc6fef [2]: https://mouha.be/sha-3-buffer-overflow/ Regression test added by: Gregory P. Smith [Google LLC] <greg@krypto.org> (cherry picked from commit 0e4e058) Co-authored-by: Theo Buehler <botovq@users.noreply.github.com>

…8528) This is a port of the applicable part of XKCP's fix [1] for CVE-2022-37454 and avoids the segmentation fault and the infinite loop in the test cases published in [2]. [1]: XKCP/XKCP@fdc6fef [2]: https://mouha.be/sha-3-buffer-overflow/ Regression test added by: Gregory P. Smith [Google LLC] <greg@krypto.org> (cherry picked from commit 0e4e058) Co-authored-by: Theo Buehler <botovq@users.noreply.github.com>

botovq added the type-bug An unexpected behavior, bug, or error label Oct 21, 2022

bedevere-bot mentioned this issue Oct 21, 2022

[3.10] gh-98517: Fix buffer overflows in _sha3 module #98519

Merged

gpshead added type-security A security issue 3.10 3.9 3.8 3.7 labels Oct 21, 2022

This was referenced Oct 21, 2022

[3.9] gh-98517: Fix buffer overflows in _sha3 module (GH-98519) #98526

Open

[3.8] gh-98517: Fix buffer overflows in _sha3 module (GH-98519) #98527

Open

[3.7] gh-98517: Fix buffer overflows in _sha3 module (GH-98519) #98528

Merged

gpshead assigned ambv, ned-deily and pablogsal Oct 21, 2022

Buffer overflow in the _sha3 module in python versions <= 3.10 #98517

Buffer overflow in the _sha3 module in python versions <= 3.10 #98517

botovq commented Oct 21, 2022 •

edited

Tasks

gpshead commented Oct 21, 2022 •

edited

Buffer overflow in the _sha3 module in python versions <= 3.10 #98517

Buffer overflow in the _sha3 module in python versions <= 3.10 #98517

Comments

botovq commented Oct 21, 2022 • edited

Tasks

gpshead commented Oct 21, 2022 • edited

botovq commented Oct 21, 2022 •

edited

gpshead commented Oct 21, 2022 •

edited