From 627ac5e314303acc00a19d58f09eb1eabd029fd1 Mon Sep 17 00:00:00 2001 From: Alex Gaynor Date: Wed, 6 Dec 2023 08:04:53 +0000 Subject: [PATCH] Fixed crash when loading a PKCS#7 bundle with no certificates (#9926) CVE: CVE-2023-49083 Upstream-Status: Backport [https://github.com/pyca/cryptography/commit/1e7b4d074e14c4e694d3ce69ad6754a6039fd6ff] Signed-off-by: Narpat Mali --- 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 5606fe6..c43fea0 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..b98a9f1 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): + 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 -- 2.40.0