Fixed crash when loading a PKCS#7 bundle with no certificates

(cherry picked from commit dc79484317e1a57a6c81319a25bd0aa7b7ac6c82)

backport-Fixed-crash-when-loading-a-PKCS-7-bundle-with-no-certificates.patch

@@ -0,0 +1,49 @@
+From a739c81fed3f87effec5bc78400658b666568a3a Mon Sep 17 00:00:00 2001
+From: Alex Gaynor <alex.gaynor@gmail.com>
+Date: Wed, 29 Nov 2023 10:05:44 +0800
+Subject: [PATCH] Fixed crash when loading a PKCS#7 bundle with no certificates
+ (#9926)
+
+---
+ 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 7364523..1a1a6d1 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..e6dcd8e 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, backend):
++        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
+-- 
+2.33.0
+

python-cryptography.spec

@@ -1,7 +1,7 @@
 %global srcname cryptography
 Name:           python-%{srcname}
 Version:        36.0.1
-Release:        3
+Release:        4
 Summary:        PyCA's cryptography library
 License:        ASL 2.0 or BSD
 URL:            https://cryptography.io/en/latest/  
@@ -9,6 +9,7 @@ Source0:        %{srcname}-%{version}.tar.gz
 
 Patch6002:      backport-provide-openssl-apis-related-to-SM-for-python.patch
 Patch6003:      backport-CVE-2023-23931.patch
+Patch6004:      backport-Fixed-crash-when-loading-a-PKCS-7-bundle-with-no-certificates.patch
 
 BuildRequires:  openssl-devel cargo
 BuildRequires:  gcc
@@ -82,6 +83,9 @@ PYTHONPATH=%{buildroot}%{python3_sitearch} %{__python3} -m pytest -k "not (test_
 %doc README.rst docs
 
 %changelog
+* Wed Nov 29 2023 liningjie <liningjie@xfusion.com> - 36.0.1-4
+- Fixed crash when loading a PKCS#7 bundle with no certificates
+
 * Thu Apr 06 2023 jichengke<jichengke2011@gmail.com> - 36.0.1-3
 - fix bogus date in changelog