/*
* This file is part of the TREZOR project, https://trezor.io/
*
* Copyright (c) SatoshiLabs
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "py/objstr.h"
#include "aes/aes.h"
#include "memzero.h"
enum AESMode {
ECB = 0x00,
CBC = 0x01,
CFB = 0x02,
OFB = 0x03,
CTR = 0x04,
};
/// class AES:
/// '''
/// AES context.
/// '''
typedef struct _mp_obj_AES_t {
mp_obj_base_t base;
aes_encrypt_ctx encrypt_ctx;
aes_decrypt_ctx decrypt_ctx;
mp_int_t mode;
uint8_t iv[AES_BLOCK_SIZE];
} mp_obj_AES_t;
/// def __init__(self, mode: int, key: bytes, iv: bytes = None) -> None:
/// '''
/// Initialize AES context.
/// '''
STATIC mp_obj_t mod_trezorcrypto_AES_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
mp_arg_check_num(n_args, n_kw, 2, 3, false);
mp_obj_AES_t *o = m_new_obj(mp_obj_AES_t);
o->base.type = type;
o->mode = mp_obj_get_int(args[0]);
if (o->mode < ECB || o->mode > CTR) {
mp_raise_ValueError("Invalid AES mode");
}
mp_buffer_info_t key;
mp_get_buffer_raise(args[1], &key, MP_BUFFER_READ);
if (key.len != 16 && key.len != 24 && key.len != 32) {
mp_raise_ValueError("Invalid length of key (has to be 128, 192 or 256 bits)");
}
if (n_args > 2) {
mp_buffer_info_t iv;
mp_get_buffer_raise(args[2], &iv, MP_BUFFER_READ);
if (iv.len != AES_BLOCK_SIZE) {
mp_raise_ValueError("Invalid length of initialization vector (has to be 128 bits)");
}
memcpy(o->iv, iv.buf, AES_BLOCK_SIZE);
} else {
memset(o->iv, 0, AES_BLOCK_SIZE);
}
switch (key.len) {
case 16:
aes_decrypt_key128(key.buf, &(o->decrypt_ctx));
aes_encrypt_key128(key.buf, &(o->encrypt_ctx));
break;
case 24:
aes_decrypt_key192(key.buf, &(o->decrypt_ctx));
aes_encrypt_key192(key.buf, &(o->encrypt_ctx));
break;
case 32:
aes_decrypt_key256(key.buf, &(o->decrypt_ctx));
aes_encrypt_key256(key.buf, &(o->encrypt_ctx));
break;
}
return MP_OBJ_FROM_PTR(o);
}
static mp_obj_t aes_update(mp_obj_t self, mp_obj_t data, bool encrypt) {
mp_buffer_info_t buf;
mp_get_buffer_raise(data, &buf, MP_BUFFER_READ);
if (buf.len == 0) {
return mp_const_empty_bytes;
}
vstr_t vstr;
vstr_init_len(&vstr, buf.len);
mp_obj_AES_t *o = MP_OBJ_TO_PTR(self);
switch (o->mode) {
case ECB:
if (buf.len & (AES_BLOCK_SIZE - 1)) {
mp_raise_ValueError("Invalid data length");
}
if (encrypt) {
aes_ecb_encrypt(buf.buf, (uint8_t *)vstr.buf, buf.len, &(o->encrypt_ctx));
} else {
aes_ecb_decrypt(buf.buf, (uint8_t *)vstr.buf, buf.len, &(o->decrypt_ctx));
}
break;
case CBC:
if (buf.len & (AES_BLOCK_SIZE - 1)) {
mp_raise_ValueError("Invalid data length");
}
if (encrypt) {
aes_cbc_encrypt(buf.buf, (uint8_t *)vstr.buf, buf.len, o->iv, &(o->encrypt_ctx));
} else {
aes_cbc_decrypt(buf.buf, (uint8_t *)vstr.buf, buf.len, o->iv, &(o->decrypt_ctx));
}
break;
case CFB:
if (encrypt) {
aes_cfb_encrypt(buf.buf, (uint8_t *)vstr.buf, buf.len, o->iv, &(o->encrypt_ctx));
} else {
aes_cfb_decrypt(buf.buf, (uint8_t *)vstr.buf, buf.len, o->iv, &(o->encrypt_ctx)); // decrypt uses encrypt_ctx
}
break;
case OFB: // (encrypt == decrypt)
aes_ofb_crypt(buf.buf, (uint8_t *)vstr.buf, buf.len, o->iv, &(o->encrypt_ctx));
break;
case CTR: // (encrypt == decrypt)
aes_ctr_crypt(buf.buf, (uint8_t *)vstr.buf, buf.len, o->iv, aes_ctr_cbuf_inc, &(o->encrypt_ctx));
break;
}
return mp_obj_new_str_from_vstr(&mp_type_bytes, &vstr);
}
/// def encrypt(self, data: bytes) -> bytes:
/// '''
/// Encrypt data and update AES context.
/// '''
STATIC mp_obj_t mod_trezorcrypto_AES_encrypt(mp_obj_t self, mp_obj_t data) {
return aes_update(self, data, true);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_trezorcrypto_AES_encrypt_obj, mod_trezorcrypto_AES_encrypt);
/// def decrypt(self, data: bytes) -> bytes:
/// '''
/// Decrypt data and update AES context.
/// '''
STATIC mp_obj_t mod_trezorcrypto_AES_decrypt(mp_obj_t self, mp_obj_t data) {
return aes_update(self, data, false);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_trezorcrypto_AES_decrypt_obj, mod_trezorcrypto_AES_decrypt);
STATIC mp_obj_t mod_trezorcrypto_AES___del__(mp_obj_t self) {
mp_obj_AES_t *o = MP_OBJ_TO_PTR(self);
memzero(&(o->encrypt_ctx), sizeof(aes_encrypt_ctx));
memzero(&(o->decrypt_ctx), sizeof(aes_decrypt_ctx));
memzero(o->iv, AES_BLOCK_SIZE);
return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_trezorcrypto_AES___del___obj, mod_trezorcrypto_AES___del__);
STATIC const mp_rom_map_elem_t mod_trezorcrypto_AES_locals_dict_table[] = {
{ MP_ROM_QSTR(MP_QSTR_encrypt), MP_ROM_PTR(&mod_trezorcrypto_AES_encrypt_obj) },
{ MP_ROM_QSTR(MP_QSTR_decrypt), MP_ROM_PTR(&mod_trezorcrypto_AES_decrypt_obj) },
{ MP_ROM_QSTR(MP_QSTR___del__), MP_ROM_PTR(&mod_trezorcrypto_AES___del___obj) },
{ MP_ROM_QSTR(MP_QSTR_ECB), MP_OBJ_NEW_SMALL_INT(ECB) },
{ MP_ROM_QSTR(MP_QSTR_CBC), MP_OBJ_NEW_SMALL_INT(CBC) },
{ MP_ROM_QSTR(MP_QSTR_CFB), MP_OBJ_NEW_SMALL_INT(CFB) },
{ MP_ROM_QSTR(MP_QSTR_OFB), MP_OBJ_NEW_SMALL_INT(OFB) },
{ MP_ROM_QSTR(MP_QSTR_CTR), MP_OBJ_NEW_SMALL_INT(CTR) },
};
STATIC MP_DEFINE_CONST_DICT(mod_trezorcrypto_AES_locals_dict, mod_trezorcrypto_AES_locals_dict_table);
STATIC const mp_obj_type_t mod_trezorcrypto_AES_type = {
{ &mp_type_type },
.name = MP_QSTR_AES,
.make_new = mod_trezorcrypto_AES_make_new,
.locals_dict = (void*)&mod_trezorcrypto_AES_locals_dict,
};