python3-cryptography: fix for CVE-2023-23931

cryptography is a package designed to expose cryptographic primitives
and recipes to Python developers. In affected versions `Cipher.update_into`
would accept Python objects which implement the buffer protocol, but
provide only immutable buffers. This would allow immutable objects
(such as `bytes`) to be mutated, thus violating fundamental rules of
Python and resulting in corrupted output. This now correctly raises
an exception. This issue has been present since `update_into` was
originally introduced in cryptography 1.8.

(From OE-Core rev: 368e450c2d800790a05924519f34c579e28e9cbb)

Signed-off-by: Narpat Mali <narpat.mali@windriver.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>

1 files changed, 49 insertions, 0 deletions

diff --git a/meta/recipes-devtools/python/python3-cryptography/CVE-2023-23931.patch b/meta/recipes-devtools/python/python3-cryptography/CVE-2023-23931.patch
new file mode 100644
index 0000000000..5fc4878978
--- /dev/null
+++ b/meta/recipes-devtools/python/python3-cryptography/CVE-2023-23931.patch
@@ -0,0 +1,49 @@
+From 9fbf84efc861668755ab645530ec7be9cf3c6696 Mon Sep 17 00:00:00 2001
+From: Alex Gaynor <alex.gaynor@gmail.com>
+Date: Tue, 7 Feb 2023 11:34:18 -0500
+Subject: [PATCH] Don't allow update_into to mutate immutable objects (#8230)
+
+CVE: CVE-2023-23931
+
+Upstream-Status: Backport [https://github.com/pyca/cryptography/commit/9fbf84efc861668755ab645530ec7be9cf3c6696]
+
+Signed-off-by: Narpat Mali <narpat.mali@windriver.com>
+---
+ src/cryptography/hazmat/backends/openssl/ciphers.py | 2 +-
+ tests/hazmat/primitives/test_ciphers.py             | 8 ++++++++
+ 2 files changed, 9 insertions(+), 1 deletion(-)
+
+diff --git a/src/cryptography/hazmat/backends/openssl/ciphers.py b/src/cryptography/hazmat/backends/openssl/ciphers.py
+index 286583f93..075d68fb9 100644
+--- a/src/cryptography/hazmat/backends/openssl/ciphers.py
++++ b/src/cryptography/hazmat/backends/openssl/ciphers.py
+@@ -156,7 +156,7 @@ class _CipherContext:
+         data_processed = 0
+         total_out = 0
+         outlen = self._backend._ffi.new("int *")
+-        baseoutbuf = self._backend._ffi.from_buffer(buf)
++        baseoutbuf = self._backend._ffi.from_buffer(buf, require_writable=True)
+         baseinbuf = self._backend._ffi.from_buffer(data)
+
+         while data_processed != total_data_len:
+diff --git a/tests/hazmat/primitives/test_ciphers.py b/tests/hazmat/primitives/test_ciphers.py
+index 02127dd9c..bf3b047de 100644
+--- a/tests/hazmat/primitives/test_ciphers.py
++++ b/tests/hazmat/primitives/test_ciphers.py
+@@ -318,6 +318,14 @@ class TestCipherUpdateInto:
+         with pytest.raises(ValueError):
+             encryptor.update_into(b"testing", buf)
+
++    def test_update_into_immutable(self, backend):
++        key = b"\x00" * 16
++        c = ciphers.Cipher(AES(key), modes.ECB(), backend)
++        encryptor = c.encryptor()
++        buf = b"\x00" * 32
++        with pytest.raises((TypeError, BufferError)):
++            encryptor.update_into(b"testing", buf)
++
+     @pytest.mark.supported(
+         only_if=lambda backend: backend.cipher_supported(
+             AES(b"\x00" * 16), modes.GCM(b"\x00" * 12)
+--
+2.40.0