From 94a50a9731f35405f0357fa5f3b177d46a726ab3 Mon Sep 17 00:00:00 2001 From: Alex Gaynor Date: Tue, 31 Jan 2023 08:33:54 -0500 Subject: [PATCH] Don't allow update_into to mutate immutable objects --- 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 286583f9325..075d68fb905 100644 --- a/src/cryptography/hazmat/backends/openssl/ciphers.py +++ b/src/cryptography/hazmat/backends/openssl/ciphers.py @@ -156,7 +156,7 @@ def update_into(self, data: bytes, buf: bytes) -> int: 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 02127dd9cab..bf3b047dec2 100644 --- a/tests/hazmat/primitives/test_ciphers.py +++ b/tests/hazmat/primitives/test_ciphers.py @@ -318,6 +318,14 @@ def test_update_into_buffer_too_small(self, backend): 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)