From f7aeb6d308004e078c11f6aaa1d5c6d1a0259146 Mon Sep 17 00:00:00 2001 From: Alex Gaynor Date: Mon, 27 Nov 2023 13:08:17 -0500 Subject: [PATCH 1/2] 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 bf34946..c7e95e5 100644 --- a/src/cryptography/hazmat/backends/openssl/backend.py +++ b/src/cryptography/hazmat/backends/openssl/backend.py @@ -2356,9 +2356,12 @@ class Backend: _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 138bc0f..b2d9757 100644 --- a/tests/hazmat/primitives/test_pkcs7.py +++ b/tests/hazmat/primitives/test_pkcs7.py @@ -89,6 +89,12 @@ class TestPKCS7Loading: 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 -- 2.43.0 From d1f3d2caa8001aa8762117dd1df710514a633c39 Mon Sep 17 00:00:00 2001 From: Paul Kehrer Date: Fri, 1 Dec 2023 13:26:38 -0600 Subject: [PATCH 2/2] raise an exception instead of returning an empty list for pkcs7 cert loading (#9947) * raise an exception instead of returning an empty list as davidben points out in #9926 we are calling a specific load certificates function and an empty value doesn't necessarily mean empty because PKCS7 contains multitudes. erroring is more correct. * changelog * Update CHANGELOG.rst Co-authored-by: Alex Gaynor --------- Co-authored-by: Alex Gaynor --- src/cryptography/hazmat/backends/openssl/backend.py | 7 +++++-- tests/hazmat/primitives/test_pkcs7.py | 4 ++-- 2 files changed, 7 insertions(+), 4 deletions(-) diff --git a/src/cryptography/hazmat/backends/openssl/backend.py b/src/cryptography/hazmat/backends/openssl/backend.py index c7e95e5..f8a2f5a 100644 --- a/src/cryptography/hazmat/backends/openssl/backend.py +++ b/src/cryptography/hazmat/backends/openssl/backend.py @@ -2356,12 +2356,15 @@ class Backend: _Reasons.UNSUPPORTED_SERIALIZATION, ) - certs: list[x509.Certificate] = [] if p7.d.sign == self._ffi.NULL: - return certs + raise ValueError( + "The provided PKCS7 has no certificate data, but a cert " + "loading method was called." + ) sk_x509 = p7.d.sign.cert num = self._lib.sk_X509_num(sk_x509) + certs: list[x509.Certificate] = [] 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 b2d9757..7b092b7 100644 --- a/tests/hazmat/primitives/test_pkcs7.py +++ b/tests/hazmat/primitives/test_pkcs7.py @@ -92,8 +92,8 @@ class TestPKCS7Loading: 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 == [] + with pytest.raises(ValueError): + pkcs7.load_der_pkcs7_certificates(der) # We have no public verification API and won't be adding one until we get -- 2.43.0