/*
* QEMU Crypto cipher built-in algorithms
*
* Copyright (c) 2015 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*
*/
#include "crypto/aes.h"
typedef struct QCryptoCipherBuiltinAESContext QCryptoCipherBuiltinAESContext;
struct QCryptoCipherBuiltinAESContext {
AES_KEY enc;
AES_KEY dec;
};
typedef struct QCryptoCipherBuiltinAES QCryptoCipherBuiltinAES;
struct QCryptoCipherBuiltinAES {
QCryptoCipher base;
QCryptoCipherBuiltinAESContext key;
uint8_t iv[AES_BLOCK_SIZE];
};
static inline bool qcrypto_length_check(size_t len, size_t blocksize,
Error **errp)
{
if (unlikely(len & (blocksize - 1))) {
error_setg(errp, "Length %zu must be a multiple of block size %zu",
len, blocksize);
return false;
}
return true;
}
static void qcrypto_cipher_ctx_free(QCryptoCipher *cipher)
{
g_free(cipher);
}
static int qcrypto_cipher_no_setiv(QCryptoCipher *cipher,
const uint8_t *iv, size_t niv,
Error **errp)
{
error_setg(errp, "Setting IV is not supported");
return -1;
}
static void do_aes_encrypt_ecb(const void *vctx,
size_t len,
uint8_t *out,
const uint8_t *in)
{
const QCryptoCipherBuiltinAESContext *ctx = vctx;
/* We have already verified that len % AES_BLOCK_SIZE == 0. */
while (len) {
AES_encrypt(in, out, &ctx->enc);
in += AES_BLOCK_SIZE;
out += AES_BLOCK_SIZE;
len -= AES_BLOCK_SIZE;
}
}
static void do_aes_decrypt_ecb(const void *vctx,
size_t len,
uint8_t *out,
const uint8_t *in)
{
const QCryptoCipherBuiltinAESContext *ctx = vctx;
/* We have already verified that len % AES_BLOCK_SIZE == 0. */
while (len) {
AES_decrypt(in, out, &ctx->dec);
in += AES_BLOCK_SIZE;
out += AES_BLOCK_SIZE;
len -= AES_BLOCK_SIZE;
}
}
static void do_aes_encrypt_cbc(const AES_KEY *key,
size_t len,
uint8_t *out,
const uint8_t *in,
uint8_t *ivec)
{
uint8_t tmp[AES_BLOCK_SIZE];
size_t n;
/* We have already verified that len % AES_BLOCK_SIZE == 0. */
while (len) {
for (n = 0; n < AES_BLOCK_SIZE; ++n) {
tmp[n] = in[n] ^ ivec[n];
}
AES_encrypt(tmp, out, key);
memcpy(ivec, out, AES_BLOCK_SIZE);
len -= AES_BLOCK_SIZE;
in += AES_BLOCK_SIZE;
out += AES_BLOCK_SIZE;
}
}
static void do_aes_decrypt_cbc(const AES_KEY *key,
size_t len,
uint8_t *out,
const uint8_t *in,
uint8_t *ivec)
{
uint8_t tmp[AES_BLOCK_SIZE];
size_t n;
/* We have already verified that len % AES_BLOCK_SIZE == 0. */
while (len) {
memcpy(tmp, in, AES_BLOCK_SIZE);
AES_decrypt(in, out, key);
for (n = 0; n < AES_BLOCK_SIZE; ++n) {
out[n] ^= ivec[n];
}
memcpy(ivec, tmp, AES_BLOCK_SIZE);
len -= AES_BLOCK_SIZE;
in += AES_BLOCK_SIZE;
out += AES_BLOCK_SIZE;
}
}
static int qcrypto_cipher_aes_encrypt_ecb(QCryptoCipher *cipher,
const void *in, void *out,
size_t len, Error **errp)
{
QCryptoCipherBuiltinAES *ctx
= container_of(cipher, QCryptoCipherBuiltinAES, base);
if (!qcrypto_length_check(len, AES_BLOCK_SIZE, errp)) {
return -1;
}
do_aes_encrypt_ecb(&ctx->key, len, out, in);
return 0;
}
static int qcrypto_cipher_aes_decrypt_ecb(QCryptoCipher *cipher,
const void *in, void *out,
size_t len, Error **errp)
{
QCryptoCipherBuiltinAES *ctx
= container_of(cipher, QCryptoCipherBuiltinAES, base);
if (!qcrypto_length_check(len, AES_BLOCK_SIZE, errp)) {
return -1;
}
do_aes_decrypt_ecb(&ctx->key, len, out, in);
return 0;
}
static int qcrypto_cipher_aes_encrypt_cbc(QCryptoCipher *cipher,
const void *in, void *out,
size_t len, Error **errp)
{
QCryptoCipherBuiltinAES *ctx
= container_of(cipher, QCryptoCipherBuiltinAES, base);
if (!qcrypto_length_check(len, AES_BLOCK_SIZE, errp)) {
return -1;
}
do_aes_encrypt_cbc(&ctx->key.enc, len, out, in, ctx->iv);
return 0;
}
static int qcrypto_cipher_aes_decrypt_cbc(QCryptoCipher *cipher,
const void *in, void *out,
size_t len, Error **errp)
{
QCryptoCipherBuiltinAES *ctx
= container_of(cipher, QCryptoCipherBuiltinAES, base);
if (!qcrypto_length_check(len, AES_BLOCK_SIZE, errp)) {
return -1;
}
do_aes_decrypt_cbc(&ctx->key.dec, len, out, in, ctx->iv);
return 0;
}
static int qcrypto_cipher_aes_setiv(QCryptoCipher *cipher, const uint8_t *iv,
size_t niv, Error **errp)
{
QCryptoCipherBuiltinAES *ctx
= container_of(cipher, QCryptoCipherBuiltinAES, base);
if (niv != AES_BLOCK_SIZE) {
error_setg(errp, "IV must be %d bytes not %zu",
AES_BLOCK_SIZE, niv);
return -1;
}
memcpy(ctx->iv, iv, AES_BLOCK_SIZE);
return 0;
}
static const struct QCryptoCipherDriver qcrypto_cipher_aes_driver_ecb = {
.cipher_encrypt = qcrypto_cipher_aes_encrypt_ecb,
.cipher_decrypt = qcrypto_cipher_aes_decrypt_ecb,
.cipher_setiv = qcrypto_cipher_no_setiv,
.cipher_free = qcrypto_cipher_ctx_free,
};
static const struct QCryptoCipherDriver qcrypto_cipher_aes_driver_cbc = {
.cipher_encrypt = qcrypto_cipher_aes_encrypt_cbc,
.cipher_decrypt = qcrypto_cipher_aes_decrypt_cbc,
.cipher_setiv = qcrypto_cipher_aes_setiv,
.cipher_free = qcrypto_cipher_ctx_free,
};
bool qcrypto_cipher_supports(QCryptoCipherAlgorithm alg,
QCryptoCipherMode mode)
{
switch (alg) {
case QCRYPTO_CIPHER_ALG_AES_128:
case QCRYPTO_CIPHER_ALG_AES_192:
case QCRYPTO_CIPHER_ALG_AES_256:
switch (mode) {
case QCRYPTO_CIPHER_MODE_ECB:
case QCRYPTO_CIPHER_MODE_CBC:
return true;
default:
return false;
}
break;
default:
return false;
}
}
static QCryptoCipher *qcrypto_cipher_ctx_new(QCryptoCipherAlgorithm alg,
QCryptoCipherMode mode,
const uint8_t *key,
size_t nkey,
Error **errp)
{
if (!qcrypto_cipher_validate_key_length(alg, mode, nkey, errp)) {
return NULL;
}
switch (alg) {
case QCRYPTO_CIPHER_ALG_AES_128:
case QCRYPTO_CIPHER_ALG_AES_192:
case QCRYPTO_CIPHER_ALG_AES_256:
{
QCryptoCipherBuiltinAES *ctx;
const QCryptoCipherDriver *drv;
switch (mode) {
case QCRYPTO_CIPHER_MODE_ECB:
drv = &qcrypto_cipher_aes_driver_ecb;
break;
case QCRYPTO_CIPHER_MODE_CBC:
drv = &qcrypto_cipher_aes_driver_cbc;
break;
default:
goto bad_mode;
}
ctx = g_new0(QCryptoCipherBuiltinAES, 1);
ctx->base.driver = drv;
if (AES_set_encrypt_key(key, nkey * 8, &ctx->key.enc)) {
error_setg(errp, "Failed to set encryption key");
goto error;
}
if (AES_set_decrypt_key(key, nkey * 8, &ctx->key.dec)) {
error_setg(errp, "Failed to set decryption key");
goto error;
}
return &ctx->base;
error:
g_free(ctx);
return NULL;
}
default:
error_setg(errp,
"Unsupported cipher algorithm %s",
QCryptoCipherAlgorithm_str(alg));
return NULL;
}
bad_mode:
error_setg(errp, "Unsupported cipher mode %s",
QCryptoCipherMode_str(mode));
return NULL;
}
