CHANGELOG.rst

@@ -1,6 +1,15 @@
 Changelog
 =========
 
+.. _v41-0-6:
+
+41.0.6 - 2023-11-27
+~~~~~~~~~~~~~~~~~~~
+
+* Fixed a null-pointer-dereference and segfault that could occur when loading
+  certificates from a PKCS#7 bundle.  Credit to **pkuzco** for reporting the
+  issue. **CVE-2023-49083**
+
 .. _v41-0-5:
 
 41.0.5 - 2023-10-24

docs/spelling_wordlist.txt

@@ -38,6 +38,7 @@ decrypted
 decrypting
 deprecations
 DER
+dereference
 deserialize
 deserialized
 Deserialization

pyproject.toml

@@ -11,7 +11,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "cryptography"
-version = "41.0.5"
+version = "41.0.6"
 authors = [
     {name = "The Python Cryptographic Authority and individual contributors", email = "cryptography-dev@python.org"}
 ]

src/cryptography/__about__.py

@@ -10,7 +10,7 @@
     "__copyright__",
 ]
 
-__version__ = "41.0.5"
+__version__ = "41.0.6"
 
 
 __author__ = "The Python Cryptographic Authority and individual contributors"

src/cryptography/hazmat/backends/openssl/backend.py

@@ -1890,9 +1890,12 @@ def _load_pkcs7_certificates(self, p7) -> typing.List[x509.Certificate]:
                 _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)

src/rust/src/lib.rs

@@ -3,6 +3,8 @@
 // for complete details.
 
 #![deny(rust_2018_idioms)]
+// Work-around for https://github.com/PyO3/pyo3/issues/3561
+#![allow(unknown_lints, clippy::unnecessary_fallible_conversions)]
 
 mod asn1;
 mod backend;

tests/hazmat/primitives/test_pkcs7.py

@@ -89,6 +89,12 @@ def test_load_pkcs7_unsupported_type(self, backend):
                 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

vectors/cryptography_vectors/__about__.py

@@ -6,4 +6,4 @@
     "__version__",
 ]
 
-__version__ = "41.0.5"
+__version__ = "41.0.6"

vectors/pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "cryptography_vectors"
-version = "41.0.5"
+version = "41.0.6"
 authors = [
     {name = "The Python Cryptographic Authority and individual contributors", email = "cryptography-dev@python.org"}
 ]