Cherry-pick fix for CVE-2023-23931 from (pyca#8230)

Don't allow update_into to mutate immutable objects pyca#8230
pyca#8230

CHANGELOG.rst

@@ -10,6 +10,9 @@ Changelog
   certificates from a PKCS#7 bundle.  Credit to **pkuzco** for reporting the
   issue. **CVE-2023-49083**
 
+* **SECURITY ISSUE** - Fixed a bug where ``Cipher.update_into`` accepted Python
+  buffer protocol objects, but allowed immutable buffers. **CVE-2023-23931**
+
 .. _v3-3-2:
 
 3.3.2 - 2021-02-07

src/cryptography/hazmat/backends/openssl/ciphers.py

@@ -135,7 +135,7 @@ def update_into(self, data, buf):
         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:

tests/hazmat/primitives/test_ciphers.py

@@ -310,6 +310,14 @@ 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)