qemu/crypto/cipher-gcrypt.c.inc

410 lines
12 KiB
C++

/*
* QEMU Crypto cipher libgcrypt 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/>.
*
*/
#ifdef CONFIG_QEMU_PRIVATE_XTS
#include "crypto/xts.h"
#endif
#include <gcrypt.h>
bool qcrypto_cipher_supports(QCryptoCipherAlgorithm alg,
QCryptoCipherMode mode)
{
switch (alg) {
case QCRYPTO_CIPHER_ALG_DES_RFB:
case QCRYPTO_CIPHER_ALG_3DES:
case QCRYPTO_CIPHER_ALG_AES_128:
case QCRYPTO_CIPHER_ALG_AES_192:
case QCRYPTO_CIPHER_ALG_AES_256:
case QCRYPTO_CIPHER_ALG_CAST5_128:
case QCRYPTO_CIPHER_ALG_SERPENT_128:
case QCRYPTO_CIPHER_ALG_SERPENT_192:
case QCRYPTO_CIPHER_ALG_SERPENT_256:
case QCRYPTO_CIPHER_ALG_TWOFISH_128:
case QCRYPTO_CIPHER_ALG_TWOFISH_256:
break;
default:
return false;
}
switch (mode) {
case QCRYPTO_CIPHER_MODE_ECB:
case QCRYPTO_CIPHER_MODE_CBC:
case QCRYPTO_CIPHER_MODE_XTS:
case QCRYPTO_CIPHER_MODE_CTR:
return true;
default:
return false;
}
}
typedef struct QCryptoCipherGcrypt {
QCryptoCipher base;
gcry_cipher_hd_t handle;
size_t blocksize;
#ifdef CONFIG_QEMU_PRIVATE_XTS
gcry_cipher_hd_t tweakhandle;
uint8_t iv[XTS_BLOCK_SIZE];
#endif
} QCryptoCipherGcrypt;
static void qcrypto_gcrypt_ctx_free(QCryptoCipher *cipher)
{
QCryptoCipherGcrypt *ctx = container_of(cipher, QCryptoCipherGcrypt, base);
gcry_cipher_close(ctx->handle);
g_free(ctx);
}
static int qcrypto_gcrypt_encrypt(QCryptoCipher *cipher, const void *in,
void *out, size_t len, Error **errp)
{
QCryptoCipherGcrypt *ctx = container_of(cipher, QCryptoCipherGcrypt, base);
gcry_error_t err;
if (len & (ctx->blocksize - 1)) {
error_setg(errp, "Length %zu must be a multiple of block size %zu",
len, ctx->blocksize);
return -1;
}
err = gcry_cipher_encrypt(ctx->handle, out, len, in, len);
if (err != 0) {
error_setg(errp, "Cannot encrypt data: %s", gcry_strerror(err));
return -1;
}
return 0;
}
static int qcrypto_gcrypt_decrypt(QCryptoCipher *cipher, const void *in,
void *out, size_t len, Error **errp)
{
QCryptoCipherGcrypt *ctx = container_of(cipher, QCryptoCipherGcrypt, base);
gcry_error_t err;
if (len & (ctx->blocksize - 1)) {
error_setg(errp, "Length %zu must be a multiple of block size %zu",
len, ctx->blocksize);
return -1;
}
err = gcry_cipher_decrypt(ctx->handle, out, len, in, len);
if (err != 0) {
error_setg(errp, "Cannot decrypt data: %s",
gcry_strerror(err));
return -1;
}
return 0;
}
static int qcrypto_gcrypt_setiv(QCryptoCipher *cipher,
const uint8_t *iv, size_t niv,
Error **errp)
{
QCryptoCipherGcrypt *ctx = container_of(cipher, QCryptoCipherGcrypt, base);
gcry_error_t err;
if (niv != ctx->blocksize) {
error_setg(errp, "Expected IV size %zu not %zu",
ctx->blocksize, niv);
return -1;
}
gcry_cipher_reset(ctx->handle);
err = gcry_cipher_setiv(ctx->handle, iv, niv);
if (err != 0) {
error_setg(errp, "Cannot set IV: %s", gcry_strerror(err));
return -1;
}
return 0;
}
static int qcrypto_gcrypt_ctr_setiv(QCryptoCipher *cipher,
const uint8_t *iv, size_t niv,
Error **errp)
{
QCryptoCipherGcrypt *ctx = container_of(cipher, QCryptoCipherGcrypt, base);
gcry_error_t err;
if (niv != ctx->blocksize) {
error_setg(errp, "Expected IV size %zu not %zu",
ctx->blocksize, niv);
return -1;
}
err = gcry_cipher_setctr(ctx->handle, iv, niv);
if (err != 0) {
error_setg(errp, "Cannot set Counter: %s", gcry_strerror(err));
return -1;
}
return 0;
}
static const struct QCryptoCipherDriver qcrypto_gcrypt_driver = {
.cipher_encrypt = qcrypto_gcrypt_encrypt,
.cipher_decrypt = qcrypto_gcrypt_decrypt,
.cipher_setiv = qcrypto_gcrypt_setiv,
.cipher_free = qcrypto_gcrypt_ctx_free,
};
static const struct QCryptoCipherDriver qcrypto_gcrypt_ctr_driver = {
.cipher_encrypt = qcrypto_gcrypt_encrypt,
.cipher_decrypt = qcrypto_gcrypt_decrypt,
.cipher_setiv = qcrypto_gcrypt_ctr_setiv,
.cipher_free = qcrypto_gcrypt_ctx_free,
};
#ifdef CONFIG_QEMU_PRIVATE_XTS
static void qcrypto_gcrypt_xts_ctx_free(QCryptoCipher *cipher)
{
QCryptoCipherGcrypt *ctx = container_of(cipher, QCryptoCipherGcrypt, base);
gcry_cipher_close(ctx->tweakhandle);
qcrypto_gcrypt_ctx_free(cipher);
}
static void qcrypto_gcrypt_xts_wrape(const void *ctx, size_t length,
uint8_t *dst, const uint8_t *src)
{
gcry_error_t err;
err = gcry_cipher_encrypt((gcry_cipher_hd_t)ctx, dst, length, src, length);
g_assert(err == 0);
}
static void qcrypto_gcrypt_xts_wrapd(const void *ctx, size_t length,
uint8_t *dst, const uint8_t *src)
{
gcry_error_t err;
err = gcry_cipher_decrypt((gcry_cipher_hd_t)ctx, dst, length, src, length);
g_assert(err == 0);
}
static int qcrypto_gcrypt_xts_encrypt(QCryptoCipher *cipher, const void *in,
void *out, size_t len, Error **errp)
{
QCryptoCipherGcrypt *ctx = container_of(cipher, QCryptoCipherGcrypt, base);
if (len & (ctx->blocksize - 1)) {
error_setg(errp, "Length %zu must be a multiple of block size %zu",
len, ctx->blocksize);
return -1;
}
xts_encrypt(ctx->handle, ctx->tweakhandle,
qcrypto_gcrypt_xts_wrape, qcrypto_gcrypt_xts_wrapd,
ctx->iv, len, out, in);
return 0;
}
static int qcrypto_gcrypt_xts_decrypt(QCryptoCipher *cipher, const void *in,
void *out, size_t len, Error **errp)
{
QCryptoCipherGcrypt *ctx = container_of(cipher, QCryptoCipherGcrypt, base);
if (len & (ctx->blocksize - 1)) {
error_setg(errp, "Length %zu must be a multiple of block size %zu",
len, ctx->blocksize);
return -1;
}
xts_decrypt(ctx->handle, ctx->tweakhandle,
qcrypto_gcrypt_xts_wrape, qcrypto_gcrypt_xts_wrapd,
ctx->iv, len, out, in);
return 0;
}
static int qcrypto_gcrypt_xts_setiv(QCryptoCipher *cipher,
const uint8_t *iv, size_t niv,
Error **errp)
{
QCryptoCipherGcrypt *ctx = container_of(cipher, QCryptoCipherGcrypt, base);
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;
}
static const struct QCryptoCipherDriver qcrypto_gcrypt_xts_driver = {
.cipher_encrypt = qcrypto_gcrypt_xts_encrypt,
.cipher_decrypt = qcrypto_gcrypt_xts_decrypt,
.cipher_setiv = qcrypto_gcrypt_xts_setiv,
.cipher_free = qcrypto_gcrypt_xts_ctx_free,
};
#endif /* CONFIG_QEMU_PRIVATE_XTS */
static QCryptoCipher *qcrypto_cipher_ctx_new(QCryptoCipherAlgorithm alg,
QCryptoCipherMode mode,
const uint8_t *key,
size_t nkey,
Error **errp)
{
QCryptoCipherGcrypt *ctx;
const QCryptoCipherDriver *drv;
gcry_error_t err;
int gcryalg, gcrymode;
if (!qcrypto_cipher_validate_key_length(alg, mode, nkey, errp)) {
return NULL;
}
switch (alg) {
case QCRYPTO_CIPHER_ALG_DES_RFB:
gcryalg = GCRY_CIPHER_DES;
break;
case QCRYPTO_CIPHER_ALG_3DES:
gcryalg = GCRY_CIPHER_3DES;
break;
case QCRYPTO_CIPHER_ALG_AES_128:
gcryalg = GCRY_CIPHER_AES128;
break;
case QCRYPTO_CIPHER_ALG_AES_192:
gcryalg = GCRY_CIPHER_AES192;
break;
case QCRYPTO_CIPHER_ALG_AES_256:
gcryalg = GCRY_CIPHER_AES256;
break;
case QCRYPTO_CIPHER_ALG_CAST5_128:
gcryalg = GCRY_CIPHER_CAST5;
break;
case QCRYPTO_CIPHER_ALG_SERPENT_128:
gcryalg = GCRY_CIPHER_SERPENT128;
break;
case QCRYPTO_CIPHER_ALG_SERPENT_192:
gcryalg = GCRY_CIPHER_SERPENT192;
break;
case QCRYPTO_CIPHER_ALG_SERPENT_256:
gcryalg = GCRY_CIPHER_SERPENT256;
break;
case QCRYPTO_CIPHER_ALG_TWOFISH_128:
gcryalg = GCRY_CIPHER_TWOFISH128;
break;
case QCRYPTO_CIPHER_ALG_TWOFISH_256:
gcryalg = GCRY_CIPHER_TWOFISH;
break;
default:
error_setg(errp, "Unsupported cipher algorithm %s",
QCryptoCipherAlgorithm_str(alg));
return NULL;
}
drv = &qcrypto_gcrypt_driver;
switch (mode) {
case QCRYPTO_CIPHER_MODE_ECB:
gcrymode = GCRY_CIPHER_MODE_ECB;
break;
case QCRYPTO_CIPHER_MODE_XTS:
#ifdef CONFIG_QEMU_PRIVATE_XTS
drv = &qcrypto_gcrypt_xts_driver;
gcrymode = GCRY_CIPHER_MODE_ECB;
#else
gcrymode = GCRY_CIPHER_MODE_XTS;
#endif
break;
case QCRYPTO_CIPHER_MODE_CBC:
gcrymode = GCRY_CIPHER_MODE_CBC;
break;
case QCRYPTO_CIPHER_MODE_CTR:
drv = &qcrypto_gcrypt_ctr_driver;
gcrymode = GCRY_CIPHER_MODE_CTR;
break;
default:
error_setg(errp, "Unsupported cipher mode %s",
QCryptoCipherMode_str(mode));
return NULL;
}
ctx = g_new0(QCryptoCipherGcrypt, 1);
ctx->base.driver = drv;
err = gcry_cipher_open(&ctx->handle, gcryalg, gcrymode, 0);
if (err != 0) {
error_setg(errp, "Cannot initialize cipher: %s",
gcry_strerror(err));
goto error;
}
ctx->blocksize = gcry_cipher_get_algo_blklen(gcryalg);
#ifdef CONFIG_QEMU_PRIVATE_XTS
if (mode == QCRYPTO_CIPHER_MODE_XTS) {
if (ctx->blocksize != XTS_BLOCK_SIZE) {
error_setg(errp,
"Cipher block size %zu must equal XTS block size %d",
ctx->blocksize, XTS_BLOCK_SIZE);
goto error;
}
err = gcry_cipher_open(&ctx->tweakhandle, gcryalg, gcrymode, 0);
if (err != 0) {
error_setg(errp, "Cannot initialize cipher: %s",
gcry_strerror(err));
goto error;
}
}
#endif
if (alg == QCRYPTO_CIPHER_ALG_DES_RFB) {
/* We're using standard DES cipher from gcrypt, so we need
* to munge the key so that the results are the same as the
* bizarre RFB variant of DES :-)
*/
uint8_t *rfbkey = qcrypto_cipher_munge_des_rfb_key(key, nkey);
err = gcry_cipher_setkey(ctx->handle, rfbkey, nkey);
g_free(rfbkey);
} else {
#ifdef CONFIG_QEMU_PRIVATE_XTS
if (mode == QCRYPTO_CIPHER_MODE_XTS) {
nkey /= 2;
err = gcry_cipher_setkey(ctx->tweakhandle, key + nkey, nkey);
if (err != 0) {
error_setg(errp, "Cannot set key: %s", gcry_strerror(err));
goto error;
}
}
#endif
err = gcry_cipher_setkey(ctx->handle, key, nkey);
}
if (err != 0) {
error_setg(errp, "Cannot set key: %s", gcry_strerror(err));
goto error;
}
return &ctx->base;
error:
#ifdef CONFIG_QEMU_PRIVATE_XTS
gcry_cipher_close(ctx->tweakhandle);
#endif
gcry_cipher_close(ctx->handle);
g_free(ctx);
return NULL;
}