second commit

venv/Lib/site-packages/cryptography/hazmat/backends/openssl/x25519.py

@@ -0,0 +1,132 @@
+# This file is dual licensed under the terms of the Apache License, Version
+# 2.0, and the BSD License. See the LICENSE file in the root of this repository
+# for complete details.
+
+import typing
+
+from cryptography.hazmat.backends.openssl.utils import _evp_pkey_derive
+from cryptography.hazmat.primitives import serialization
+from cryptography.hazmat.primitives.asymmetric.x25519 import (
+    X25519PrivateKey,
+    X25519PublicKey,
+)
+
+if typing.TYPE_CHECKING:
+    from cryptography.hazmat.backends.openssl.backend import Backend
+
+
+_X25519_KEY_SIZE = 32
+
+
+class _X25519PublicKey(X25519PublicKey):
+    def __init__(self, backend: "Backend", evp_pkey):
+        self._backend = backend
+        self._evp_pkey = evp_pkey
+
+    def public_bytes(
+        self,
+        encoding: serialization.Encoding,
+        format: serialization.PublicFormat,
+    ) -> bytes:
+        if (
+            encoding is serialization.Encoding.Raw
+            or format is serialization.PublicFormat.Raw
+        ):
+            if (
+                encoding is not serialization.Encoding.Raw
+                or format is not serialization.PublicFormat.Raw
+            ):
+                raise ValueError(
+                    "When using Raw both encoding and format must be Raw"
+                )
+
+            return self._raw_public_bytes()
+
+        return self._backend._public_key_bytes(
+            encoding, format, self, self._evp_pkey, None
+        )
+
+    def _raw_public_bytes(self) -> bytes:
+        ucharpp = self._backend._ffi.new("unsigned char **")
+        res = self._backend._lib.EVP_PKEY_get1_tls_encodedpoint(
+            self._evp_pkey, ucharpp
+        )
+        self._backend.openssl_assert(res == 32)
+        self._backend.openssl_assert(ucharpp[0] != self._backend._ffi.NULL)
+        data = self._backend._ffi.gc(
+            ucharpp[0], self._backend._lib.OPENSSL_free
+        )
+        return self._backend._ffi.buffer(data, res)[:]
+
+
+class _X25519PrivateKey(X25519PrivateKey):
+    def __init__(self, backend: "Backend", evp_pkey):
+        self._backend = backend
+        self._evp_pkey = evp_pkey
+
+    def public_key(self) -> X25519PublicKey:
+        bio = self._backend._create_mem_bio_gc()
+        res = self._backend._lib.i2d_PUBKEY_bio(bio, self._evp_pkey)
+        self._backend.openssl_assert(res == 1)
+        evp_pkey = self._backend._lib.d2i_PUBKEY_bio(
+            bio, self._backend._ffi.NULL
+        )
+        self._backend.openssl_assert(evp_pkey != self._backend._ffi.NULL)
+        evp_pkey = self._backend._ffi.gc(
+            evp_pkey, self._backend._lib.EVP_PKEY_free
+        )
+        return _X25519PublicKey(self._backend, evp_pkey)
+
+    def exchange(self, peer_public_key: X25519PublicKey) -> bytes:
+        if not isinstance(peer_public_key, X25519PublicKey):
+            raise TypeError("peer_public_key must be X25519PublicKey.")
+
+        return _evp_pkey_derive(self._backend, self._evp_pkey, peer_public_key)
+
+    def private_bytes(
+        self,
+        encoding: serialization.Encoding,
+        format: serialization.PrivateFormat,
+        encryption_algorithm: serialization.KeySerializationEncryption,
+    ) -> bytes:
+        if (
+            encoding is serialization.Encoding.Raw
+            or format is serialization.PublicFormat.Raw
+        ):
+            if (
+                format is not serialization.PrivateFormat.Raw
+                or encoding is not serialization.Encoding.Raw
+                or not isinstance(
+                    encryption_algorithm, serialization.NoEncryption
+                )
+            ):
+                raise ValueError(
+                    "When using Raw both encoding and format must be Raw "
+                    "and encryption_algorithm must be NoEncryption()"
+                )
+
+            return self._raw_private_bytes()
+
+        return self._backend._private_key_bytes(
+            encoding, format, encryption_algorithm, self, self._evp_pkey, None
+        )
+
+    def _raw_private_bytes(self) -> bytes:
+        # When we drop support for CRYPTOGRAPHY_OPENSSL_LESS_THAN_111 we can
+        # switch this to EVP_PKEY_new_raw_private_key
+        # The trick we use here is serializing to a PKCS8 key and just
+        # using the last 32 bytes, which is the key itself.
+        bio = self._backend._create_mem_bio_gc()
+        res = self._backend._lib.i2d_PKCS8PrivateKey_bio(
+            bio,
+            self._evp_pkey,
+            self._backend._ffi.NULL,
+            self._backend._ffi.NULL,
+            0,
+            self._backend._ffi.NULL,
+            self._backend._ffi.NULL,
+        )
+        self._backend.openssl_assert(res == 1)
+        pkcs8 = self._backend._read_mem_bio(bio)
+        self._backend.openssl_assert(len(pkcs8) == 48)
+        return pkcs8[-_X25519_KEY_SIZE:]