KittyPatch/kitty
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Add tests for AES256GCM

Browse Source
This commit is contained in:
Kovid Goyal 2022-08-05 13:50:03 +05:30
parent 384eba6cd4
commit a7b7fb560a
No known key found for this signature in database
GPG Key ID: 06BC317B515ACE7C
2 changed files with 43 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
kitty/crypto.c
View File

@ -355,23 +355,22 @@ typedef struct {
PyObject_HEAD
EVP_CIPHER_CTX *ctx;
unsigned char iv[12], tag[16];
int state;
} AES256GCMDecrypt;
static PyObject *
new_aes256gcmdecrypt(PyTypeObject *type, PyObject *args, PyObject *kwds UNUSED) {
Secret *key; const unsigned char *iv, *tag; Py_ssize_t iv_len, tag_len;
Secret *key; unsigned char *iv, *tag; Py_ssize_t iv_len, tag_len;
if (!PyArg_ParseTuple(args, "O!y#y#", &Secret_Type, &key, &iv, &iv_len, &tag, &tag_len)) return NULL;
if (key->secret_len != 32) { PyErr_SetString(PyExc_ValueError, "The key for AES 256 GCM must be 32 bytes long"); return NULL; }
if (iv_len != sizeof ((AES256GCMDecrypt*)0)->iv) { PyErr_SetString(PyExc_ValueError, "Incorrect iv length for AES 256 GCM"); return NULL; }
if (tag_len != sizeof ((AES256GCMDecrypt*)0)->tag) { PyErr_SetString(PyExc_ValueError, "Incorrect tag length for AES 256 GCM"); return NULL; }
if (iv_len != 12) { PyErr_SetString(PyExc_ValueError, "Incorrect iv length for AES 256 GCM"); return NULL; }
if (tag_len != 16) { PyErr_SetString(PyExc_ValueError, "Incorrect tag length for AES 256 GCM"); return NULL; }
AES256GCMDecrypt *self = (AES256GCMDecrypt *)type->tp_alloc(type, 0);
if (!self) return NULL;
if (!(self->ctx = EVP_CIPHER_CTX_new())) { Py_CLEAR(self); return set_error_from_openssl("Failed to allocate decryption context"); }
memcpy(self->iv, iv, iv_len); memcpy(self->tag, tag, tag_len);
if (1 != EVP_DecryptInit_ex(self->ctx, EVP_aes_256_gcm(), NULL, key->secret, self->iv)) {
if (1 != EVP_DecryptInit_ex(self->ctx, EVP_aes_256_gcm(), NULL, key->secret, iv)) {
Py_CLEAR(self); return set_error_from_openssl("Failed to initialize encryption context"); }
if (!EVP_CIPHER_CTX_ctrl(self->ctx, EVP_CTRL_GCM_SET_TAG, tag_len, tag)) { Py_CLEAR(self); return set_error_from_openssl("Failed to set the tag"); }
return (PyObject*)self;
}
@ -397,7 +396,7 @@ add_data_to_be_decrypted(AES256GCMDecrypt *self, PyObject *args) {
const char *ciphertext; Py_ssize_t ciphertext_len;
int finish_decryption = 0;
if (!PyArg_ParseTuple(args, "y#|p", &ciphertext, &ciphertext_len, &finish_decryption)) return NULL;
PyObject *plaintext = PyBytes_FromStringAndSize(NULL, ciphertext_len + 256);
PyObject *plaintext = PyBytes_FromStringAndSize(NULL, ciphertext_len + 2 * EVP_CIPHER_CTX_block_size(self->ctx));
if (!plaintext) return NULL;
self->state = 1;
int offset = 0;
@ -409,12 +408,12 @@ add_data_to_be_decrypted(AES256GCMDecrypt *self, PyObject *args) {
}
if (finish_decryption) {
int len = PyBytes_GET_SIZE(plaintext) - offset;
if (0 <= EVP_DecryptFinal_ex(self->ctx, (unsigned char*)PyBytes_AS_STRING(plaintext) + offset, &len)) {
Py_CLEAR(plaintext); return set_error_from_openssl("Failed to finish decryption"); }
offset += len;
int ret = EVP_DecryptFinal_ex(self->ctx, (unsigned char*)PyBytes_AS_STRING(plaintext) + offset, &len);
self->state = 2;
if (ret <= 0) { Py_CLEAR(plaintext); PyErr_SetString(Crypto_Exception, "Failed to finish decrypt"); return NULL; }
offset += len;
}
if (offset != PyBytes_GET_SIZE(ciphertext)) { _PyBytes_Resize(&plaintext, offset); if (!plaintext) return NULL; }
if (offset != PyBytes_GET_SIZE(plaintext)) { _PyBytes_Resize(&plaintext, offset); if (!plaintext) return NULL; }
return plaintext;
}

34
kitty_tests/crypto.py
View File

@ -2,13 +2,17 @@
# License: GPLv3 Copyright: 2022, Kovid Goyal <kovid at kovidgoyal.net>
import os
from . import BaseTest
class TestCrypto(BaseTest):
def test_elliptic_curve_data_exchange(self):
from kitty.fast_data_types import EllipticCurveKey
from kitty.fast_data_types import (
AES256GCMDecrypt, AES256GCMEncrypt, CryptoError, EllipticCurveKey
)
alice = EllipticCurveKey()
bob = EllipticCurveKey()
alice_secret = alice.derive_secret(bob.public)
@ -16,3 +20,31 @@ class TestCrypto(BaseTest):
self.assertEqual(len(alice_secret), 32)
self.assertEqual(len(bob_secret), 32)
self.assertEqual(alice_secret, bob_secret)
auth_data = os.urandom(213)
plaintext = os.urandom(1011)
e = AES256GCMEncrypt(alice_secret)
e.add_authenticated_but_unencrypted_data(auth_data)
ciphertext = e.add_data_to_be_encrypted(plaintext, True)
d = AES256GCMDecrypt(bob_secret, e.iv, e.tag)
d.add_data_to_be_authenticated_but_not_decrypted(auth_data)
q = d.add_data_to_be_decrypted(ciphertext, True)
self.ae(q, plaintext)
def corrupt_data(data):
b = bytearray(data)
b[0] = (b[0] + 13) % 256
return bytes(b)
d = AES256GCMDecrypt(bob_secret, e.iv, corrupt_data(e.tag))
d.add_data_to_be_authenticated_but_not_decrypted(auth_data)
self.assertRaises(CryptoError, d.add_data_to_be_decrypted, ciphertext, True)
d = AES256GCMDecrypt(bob_secret, e.iv, e.tag)
d.add_data_to_be_authenticated_but_not_decrypted(corrupt_data(auth_data))
self.assertRaises(CryptoError, d.add_data_to_be_decrypted, ciphertext, True)
d = AES256GCMDecrypt(bob_secret, e.iv, e.tag)
d.add_data_to_be_authenticated_but_not_decrypted(auth_data)
self.assertRaises(CryptoError, d.add_data_to_be_decrypted, corrupt_data(ciphertext), True)