From 5d30bfa2e64fc10f5fad8eb7c2c4bcc126433328 Mon Sep 17 00:00:00 2001 From: Anselm Kruis Date: Tue, 3 Dec 2024 11:40:20 +0100 Subject: [PATCH] Fixed crash when loading a PKCS#7 bundle with no certificates (#9926) Backport of f09c261ca10a31fe41b1262306db7f8f1da0e48a Fix CVE-2023-49083 --- 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 97c7fd054495..b604446f6eb7 100644 --- a/src/cryptography/hazmat/backends/openssl/backend.py +++ b/src/cryptography/hazmat/backends/openssl/backend.py @@ -2675,9 +2675,12 @@ def _load_pkcs7_certificates(self, p7): _Reasons.UNSUPPORTED_SERIALIZATION, ) + certs = [] + 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 b7afe7512ac2..11d93010e5bd 100644 --- a/tests/hazmat/primitives/test_pkcs7.py +++ b/tests/hazmat/primitives/test_pkcs7.py @@ -77,3 +77,9 @@ def test_load_pkcs7_unsupported_type(self): ), 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 == []