From 9a2be4e2d38ab8631ff3f2e71757265ab6e064fc Mon Sep 17 00:00:00 2001
From: Alex Gaynor <alex.gaynor@gmail.com>
Date: Mon, 19 Feb 2024 11:50:28 -0500
Subject: [PATCH] Fixes #10422 -- don't crash when a PKCS#12 key and cert don't
 match (#10423)

---
 .../hazmat/backends/openssl/backend.py         |  9 +++++++++
 tests/hazmat/primitives/test_pkcs12.py         | 18 ++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/src/cryptography/hazmat/backends/openssl/backend.py b/src/cryptography/hazmat/backends/openssl/backend.py
index 5cd1103bd133..66053af7f937 100644
--- a/src/cryptography/hazmat/backends/openssl/backend.py
+++ b/src/cryptography/hazmat/backends/openssl/backend.py
@@ -826,6 +826,15 @@ def serialize_key_and_certificates_to_pkcs12(
                     mac_iter,
                     0,
                 )
+                if p12 == self._ffi.NULL:
+                    errors = self._consume_errors()
+                    raise ValueError(
+                        (
+                            "Failed to create PKCS12 (does the key match the "
+                            "certificate?)"
+                        ),
+                        errors,
+                    )
 
             if (
                 self._lib.Cryptography_HAS_PKCS12_SET_MAC
diff --git a/tests/hazmat/primitives/test_pkcs12.py b/tests/hazmat/primitives/test_pkcs12.py
index cd9c279ac4b0..cd7bcafc6e73 100644
--- a/tests/hazmat/primitives/test_pkcs12.py
+++ b/tests/hazmat/primitives/test_pkcs12.py
@@ -657,6 +657,24 @@ def test_key_serialization_encryption_set_mac_unsupported(
                 b"name", cakey, cacert, [], algorithm
             )
 
+    @pytest.mark.supported(
+        only_if=lambda backend: backend._lib.Cryptography_HAS_PKCS12_SET_MAC,
+        skip_message="Requires OpenSSL with PKCS12_set_mac",
+    )
+    def test_set_mac_key_certificate_mismatch(self, backend):
+        cacert, _ = _load_ca(backend)
+        key = ec.generate_private_key(ec.SECP256R1())
+        encryption = (
+            serialization.PrivateFormat.PKCS12.encryption_builder()
+            .hmac_hash(hashes.SHA256())
+            .build(b"password")
+        )
+
+        with pytest.raises(ValueError):
+            serialize_key_and_certificates(
+                b"name", key, cacert, [], encryption
+            )
+
 
 @pytest.mark.skip_fips(
     reason="PKCS12 unsupported in FIPS mode. So much bad crypto in it."