python3-cryptography: fix CVE-2023-49083

cryptography is a package designed to expose cryptographic primitives
and recipes to Python developers. Calling `load_pem_pkcs7_certificates`
or `load_der_pkcs7_certificates` could lead to a NULL-pointer dereference
and segfault. Exploitation of this vulnerability poses a serious risk of
Denial of Service (DoS) for any application attempting to deserialize a
PKCS7 blob/certificate. The consequences extend to potential disruptions
in system availability and stability. This vulnerability has been patched
in version 41.0.6.

References:
https://nvd.nist.gov/vuln/detail/CVE-2023-49083
https://security-tracker.debian.org/tracker/CVE-2023-49083

(From OE-Core rev: 2d104f78cd13a10640bc284c7fc8358bf305279c)

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

2 files changed, 54 insertions, 0 deletions

diff --git a/meta/recipes-devtools/python/python3-cryptography/CVE-2023-49083.patch b/meta/recipes-devtools/python/python3-cryptography/CVE-2023-49083.patch
new file mode 100644
index 0000000000..d398eea1d9
--- /dev/null
+++ b/meta/recipes-devtools/python/python3-cryptography/CVE-2023-49083.patch
@@ -0,0 +1,53 @@
+From 627ac5e314303acc00a19d58f09eb1eabd029fd1 Mon Sep 17 00:00:00 2001
+From: Alex Gaynor <alex.gaynor@gmail.com>
+Date: Wed, 6 Dec 2023 08:04:53 +0000
+Subject: [PATCH] Fixed crash when loading a PKCS#7 bundle with no certificates
+ (#9926)
+
+CVE: CVE-2023-49083
+
+Upstream-Status: Backport [https://github.com/pyca/cryptography/commit/1e7b4d074e14c4e694d3ce69ad6754a6039fd6ff]
+
+Signed-off-by: Narpat Mali <narpat.mali@windriver.com>
+---
+ src/cryptography/hazmat/backends/openssl/backend.py | 5 ++++-
+ tests/hazmat/primitives/test_pkcs7.py               | 6 ++++++
+ 2 files changed, 10 insertions(+), 1 deletion(-)
+
+diff --git a/src/cryptography/hazmat/backends/openssl/backend.py b/src/cryptography/hazmat/backends/openssl/backend.py
+index 5606fe6..c43fea0 100644
+--- a/src/cryptography/hazmat/backends/openssl/backend.py
++++ b/src/cryptography/hazmat/backends/openssl/backend.py
+@@ -2189,9 +2189,12 @@ class Backend(BackendInterface):
+                 _Reasons.UNSUPPORTED_SERIALIZATION,
+             )
+
++        certs: list[x509.Certificate] = []
++        if p7.d.sign == self._ffi.NULL:
++            return certs
++
+         sk_x509 = p7.d.sign.cert
+         num = self._lib.sk_X509_num(sk_x509)
+-        certs = []
+         for i in range(num):
+             x509 = self._lib.sk_X509_value(sk_x509, i)
+             self.openssl_assert(x509 != self._ffi.NULL)
+diff --git a/tests/hazmat/primitives/test_pkcs7.py b/tests/hazmat/primitives/test_pkcs7.py
+index 91ac842..b98a9f1 100644
+--- a/tests/hazmat/primitives/test_pkcs7.py
++++ b/tests/hazmat/primitives/test_pkcs7.py
+@@ -81,6 +81,12 @@ class TestPKCS7Loading(object):
+                 mode="rb",
+             )
+
++    def test_load_pkcs7_empty_certificates(self):
++        der = b"\x30\x0B\x06\x09\x2A\x86\x48\x86\xF7\x0D\x01\x07\x02"
++
++        certificates = pkcs7.load_der_pkcs7_certificates(der)
++        assert certificates == []
++
+
+ # We have no public verification API and won't be adding one until we get
+ # some requirements from users so this function exists to give us basic
+--
+2.40.0
diff --git a/meta/recipes-devtools/python/python3-cryptography_36.0.2.bb b/meta/recipes-devtools/python/python3-cryptography_36.0.2.bb
index c3ae0c1ab9..c429c75e1b 100644
--- a/meta/recipes-devtools/python/python3-cryptography_36.0.2.bb
+++ b/meta/recipes-devtools/python/python3-cryptography_36.0.2.bb
@@ -18,6 +18,7 @@ SRC_URI += " \
     file://0002-Cargo.toml-edition-2018-2021.patch \
     file://fix-leak-metric.patch \
     file://CVE-2023-23931.patch \
+    file://CVE-2023-49083.patch \
 "
 
 inherit pypi python_setuptools3_rust