From: Alex Gaynor Date: Tue, 7 Feb 2023 11:34:18 -0500 Subject: Don't allow update_into to mutate immutable objects (#8230) Origin: https://github.com/pyca/cryptography/commit/9fbf84efc861668755ab645530ec7be9cf3c6696 Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2023-23931 Bug-Debian: https://bugs.debian.org/1031049 --- src/cryptography/hazmat/backends/openssl/ciphers.py | 2 +- tests/hazmat/primitives/test_ciphers.py | 8 ++++++++ 2 files changed, 9 insertions(+), 1 deletion(-) diff --git a/src/cryptography/hazmat/backends/openssl/ciphers.py b/src/cryptography/hazmat/backends/openssl/ciphers.py index 286583f93255..075d68fb9057 100644 --- a/src/cryptography/hazmat/backends/openssl/ciphers.py +++ b/src/cryptography/hazmat/backends/openssl/ciphers.py @@ -156,7 +156,7 @@ class _CipherContext: data_processed = 0 total_out = 0 outlen = self._backend._ffi.new("int *") - baseoutbuf = self._backend._ffi.from_buffer(buf) + baseoutbuf = self._backend._ffi.from_buffer(buf, require_writable=True) baseinbuf = self._backend._ffi.from_buffer(data) while data_processed != total_data_len: diff --git a/tests/hazmat/primitives/test_ciphers.py b/tests/hazmat/primitives/test_ciphers.py index 02127dd9cab5..bf3b047dec25 100644 --- a/tests/hazmat/primitives/test_ciphers.py +++ b/tests/hazmat/primitives/test_ciphers.py @@ -318,6 +318,14 @@ class TestCipherUpdateInto: with pytest.raises(ValueError): encryptor.update_into(b"testing", buf) + def test_update_into_immutable(self, backend): + key = b"\x00" * 16 + c = ciphers.Cipher(AES(key), modes.ECB(), backend) + encryptor = c.encryptor() + buf = b"\x00" * 32 + with pytest.raises((TypeError, BufferError)): + encryptor.update_into(b"testing", buf) + @pytest.mark.supported( only_if=lambda backend: backend.cipher_supported( AES(b"\x00" * 16), modes.GCM(b"\x00" * 12) -- 2.39.2