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/*
* QEMU Crypto cipher nettle 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 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 <nettle/nettle-types.h>
#include <nettle/aes.h>
#include <nettle/des.h>
#include <nettle/cbc.h>
#if CONFIG_NETTLE_VERSION_MAJOR < 3
typedef nettle_crypt_func nettle_cipher_func;
typedef void * cipher_ctx_t;
typedef unsigned cipher_length_t;
#else
typedef const void * cipher_ctx_t;
typedef size_t cipher_length_t;
#endif
static nettle_cipher_func aes_encrypt_wrapper;
static nettle_cipher_func aes_decrypt_wrapper;
static nettle_cipher_func des_encrypt_wrapper;
static nettle_cipher_func des_decrypt_wrapper;
static void aes_encrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
uint8_t *dst, const uint8_t *src)
{
aes_encrypt(ctx, length, dst, src);
}
static void aes_decrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
uint8_t *dst, const uint8_t *src)
{
aes_decrypt(ctx, length, dst, src);
}
static void des_encrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
uint8_t *dst, const uint8_t *src)
{
des_encrypt(ctx, length, dst, src);
}
static void des_decrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
uint8_t *dst, const uint8_t *src)
{
des_decrypt(ctx, length, dst, src);
}
typedef struct QCryptoCipherNettle QCryptoCipherNettle;
struct QCryptoCipherNettle {
void *ctx_encrypt;
void *ctx_decrypt;
nettle_cipher_func *alg_encrypt;
nettle_cipher_func *alg_decrypt;
uint8_t *iv;
size_t blocksize;
};
bool qcrypto_cipher_supports(QCryptoCipherAlgorithm alg)
{
switch (alg) {
case QCRYPTO_CIPHER_ALG_DES_RFB:
case QCRYPTO_CIPHER_ALG_AES_128:
case QCRYPTO_CIPHER_ALG_AES_192:
case QCRYPTO_CIPHER_ALG_AES_256:
return true;
default:
return false;
}
}
QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm alg,
QCryptoCipherMode mode,
const uint8_t *key, size_t nkey,
Error **errp)
{
QCryptoCipher *cipher;
QCryptoCipherNettle *ctx;
uint8_t *rfbkey;
switch (mode) {
case QCRYPTO_CIPHER_MODE_ECB:
case QCRYPTO_CIPHER_MODE_CBC:
break;
default:
error_setg(errp, "Unsupported cipher mode %d", mode);
return NULL;
}
if (!qcrypto_cipher_validate_key_length(alg, nkey, errp)) {
return NULL;
}
cipher = g_new0(QCryptoCipher, 1);
cipher->alg = alg;
cipher->mode = mode;
ctx = g_new0(QCryptoCipherNettle, 1);
switch (alg) {
case QCRYPTO_CIPHER_ALG_DES_RFB:
ctx->ctx_encrypt = g_new0(struct des_ctx, 1);
ctx->ctx_decrypt = NULL; /* 1 ctx can do both */
rfbkey = qcrypto_cipher_munge_des_rfb_key(key, nkey);
des_set_key(ctx->ctx_encrypt, rfbkey);
g_free(rfbkey);
ctx->alg_encrypt = des_encrypt_wrapper;
ctx->alg_decrypt = des_decrypt_wrapper;
ctx->blocksize = DES_BLOCK_SIZE;
break;
case QCRYPTO_CIPHER_ALG_AES_128:
case QCRYPTO_CIPHER_ALG_AES_192:
case QCRYPTO_CIPHER_ALG_AES_256:
ctx->ctx_encrypt = g_new0(struct aes_ctx, 1);
ctx->ctx_decrypt = g_new0(struct aes_ctx, 1);
aes_set_encrypt_key(ctx->ctx_encrypt, nkey, key);
aes_set_decrypt_key(ctx->ctx_decrypt, nkey, key);
ctx->alg_encrypt = aes_encrypt_wrapper;
ctx->alg_decrypt = aes_decrypt_wrapper;
ctx->blocksize = AES_BLOCK_SIZE;
break;
default:
error_setg(errp, "Unsupported cipher algorithm %d", alg);
goto error;
}
ctx->iv = g_new0(uint8_t, ctx->blocksize);
cipher->opaque = ctx;
return cipher;
error:
g_free(cipher);
g_free(ctx);
return NULL;
}
void qcrypto_cipher_free(QCryptoCipher *cipher)
{
QCryptoCipherNettle *ctx;
if (!cipher) {
return;
}
ctx = cipher->opaque;
g_free(ctx->iv);
g_free(ctx->ctx_encrypt);
g_free(ctx->ctx_decrypt);
g_free(ctx);
g_free(cipher);
}
int qcrypto_cipher_encrypt(QCryptoCipher *cipher,
const void *in,
void *out,
size_t len,
Error **errp)
{
QCryptoCipherNettle *ctx = cipher->opaque;
if (len % ctx->blocksize) {
error_setg(errp, "Length %zu must be a multiple of block size %zu",
len, ctx->blocksize);
return -1;
}
switch (cipher->mode) {
case QCRYPTO_CIPHER_MODE_ECB:
ctx->alg_encrypt(ctx->ctx_encrypt, len, out, in);
break;
case QCRYPTO_CIPHER_MODE_CBC:
cbc_encrypt(ctx->ctx_encrypt, ctx->alg_encrypt,
ctx->blocksize, ctx->iv,
len, out, in);
break;
default:
error_setg(errp, "Unsupported cipher algorithm %d",
cipher->alg);
return -1;
}
return 0;
}
int qcrypto_cipher_decrypt(QCryptoCipher *cipher,
const void *in,
void *out,
size_t len,
Error **errp)
{
QCryptoCipherNettle *ctx = cipher->opaque;
if (len % ctx->blocksize) {
error_setg(errp, "Length %zu must be a multiple of block size %zu",
len, ctx->blocksize);
return -1;
}
switch (cipher->mode) {
case QCRYPTO_CIPHER_MODE_ECB:
ctx->alg_decrypt(ctx->ctx_decrypt ? ctx->ctx_decrypt : ctx->ctx_encrypt,
len, out, in);
break;
case QCRYPTO_CIPHER_MODE_CBC:
cbc_decrypt(ctx->ctx_decrypt ? ctx->ctx_decrypt : ctx->ctx_encrypt,
ctx->alg_decrypt, ctx->blocksize, ctx->iv,
len, out, in);
break;
default:
error_setg(errp, "Unsupported cipher algorithm %d",
cipher->alg);
return -1;
}
return 0;
}
int qcrypto_cipher_setiv(QCryptoCipher *cipher,
const uint8_t *iv, size_t niv,
Error **errp)
{
QCryptoCipherNettle *ctx = cipher->opaque;
if (niv != ctx->blocksize) {
error_setg(errp, "Expected IV size %zu not %zu",
ctx->blocksize, niv);
return -1;
}
memcpy(ctx->iv, iv, niv);
return 0;
}