qemu/crypto/cipher-gcrypt.c
Daniel P. Berrangé e0576942e0 crypto: add support for gcrypt's native XTS impl
Libgcrypt 1.8.0 added support for the XTS mode. Use this because long
term we wish to delete QEMU's XTS impl to avoid carrying private crypto
algorithm impls.

As an added benefit, using this improves performance from 531 MB/sec to
670 MB/sec, since we are avoiding several layers of function call
indirection.

This is even more noticable with the gcrypt builds in Fedora or RHEL-8
which have a non-upstream patch for FIPS mode which does mutex locking.
This is catastrophic for encryption performance with small block sizes,
meaning this patch improves encryption from 240 MB/sec to 670 MB/sec.

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-10-28 16:20:28 +01:00

423 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/>.
*
*/
#include "qemu/osdep.h"
#ifdef CONFIG_QEMU_PRIVATE_XTS
#include "crypto/xts.h"
#endif
#include "cipherpriv.h"
#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 QCryptoCipherGcrypt;
struct QCryptoCipherGcrypt {
gcry_cipher_hd_t handle;
size_t blocksize;
#ifdef CONFIG_QEMU_PRIVATE_XTS
gcry_cipher_hd_t tweakhandle;
/* Initialization vector or Counter */
uint8_t *iv;
#endif
};
static void
qcrypto_gcrypt_cipher_free_ctx(QCryptoCipherGcrypt *ctx,
QCryptoCipherMode mode)
{
if (!ctx) {
return;
}
gcry_cipher_close(ctx->handle);
#ifdef CONFIG_QEMU_PRIVATE_XTS
if (mode == QCRYPTO_CIPHER_MODE_XTS) {
gcry_cipher_close(ctx->tweakhandle);
}
g_free(ctx->iv);
#endif
g_free(ctx);
}
static QCryptoCipherGcrypt *qcrypto_cipher_ctx_new(QCryptoCipherAlgorithm alg,
QCryptoCipherMode mode,
const uint8_t *key,
size_t nkey,
Error **errp)
{
QCryptoCipherGcrypt *ctx;
gcry_error_t err;
int gcryalg, gcrymode;
switch (mode) {
case QCRYPTO_CIPHER_MODE_ECB:
gcrymode = GCRY_CIPHER_MODE_ECB;
break;
case QCRYPTO_CIPHER_MODE_XTS:
#ifdef CONFIG_QEMU_PRIVATE_XTS
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:
gcrymode = GCRY_CIPHER_MODE_CTR;
break;
default:
error_setg(errp, "Unsupported cipher mode %s",
QCryptoCipherMode_str(mode));
return NULL;
}
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;
}
ctx = g_new0(QCryptoCipherGcrypt, 1);
err = gcry_cipher_open(&ctx->handle, gcryalg, gcrymode, 0);
if (err != 0) {
error_setg(errp, "Cannot initialize cipher: %s",
gcry_strerror(err));
goto error;
}
#ifdef CONFIG_QEMU_PRIVATE_XTS
if (mode == QCRYPTO_CIPHER_MODE_XTS) {
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);
ctx->blocksize = 8;
} else {
#ifdef CONFIG_QEMU_PRIVATE_XTS
if (mode == QCRYPTO_CIPHER_MODE_XTS) {
nkey /= 2;
err = gcry_cipher_setkey(ctx->handle, key, nkey);
if (err != 0) {
error_setg(errp, "Cannot set key: %s",
gcry_strerror(err));
goto error;
}
err = gcry_cipher_setkey(ctx->tweakhandle, key + nkey, nkey);
} else {
#endif
err = gcry_cipher_setkey(ctx->handle, key, nkey);
#ifdef CONFIG_QEMU_PRIVATE_XTS
}
#endif
if (err != 0) {
error_setg(errp, "Cannot set key: %s",
gcry_strerror(err));
goto error;
}
switch (alg) {
case QCRYPTO_CIPHER_ALG_AES_128:
case QCRYPTO_CIPHER_ALG_AES_192:
case QCRYPTO_CIPHER_ALG_AES_256:
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:
ctx->blocksize = 16;
break;
case QCRYPTO_CIPHER_ALG_3DES:
case QCRYPTO_CIPHER_ALG_CAST5_128:
ctx->blocksize = 8;
break;
default:
g_assert_not_reached();
}
}
#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;
}
ctx->iv = g_new0(uint8_t, ctx->blocksize);
}
#endif
return ctx;
error:
qcrypto_gcrypt_cipher_free_ctx(ctx, mode);
return NULL;
}
static void
qcrypto_gcrypt_cipher_ctx_free(QCryptoCipher *cipher)
{
qcrypto_gcrypt_cipher_free_ctx(cipher->opaque, cipher->mode);
}
#ifdef CONFIG_QEMU_PRIVATE_XTS
static void qcrypto_gcrypt_xts_encrypt(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_decrypt(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);
}
#endif
static int
qcrypto_gcrypt_cipher_encrypt(QCryptoCipher *cipher,
const void *in,
void *out,
size_t len,
Error **errp)
{
QCryptoCipherGcrypt *ctx = cipher->opaque;
gcry_error_t err;
if (len % ctx->blocksize) {
error_setg(errp, "Length %zu must be a multiple of block size %zu",
len, ctx->blocksize);
return -1;
}
#ifdef CONFIG_QEMU_PRIVATE_XTS
if (cipher->mode == QCRYPTO_CIPHER_MODE_XTS) {
xts_encrypt(ctx->handle, ctx->tweakhandle,
qcrypto_gcrypt_xts_encrypt,
qcrypto_gcrypt_xts_decrypt,
ctx->iv, len, out, in);
return 0;
}
#endif
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_cipher_decrypt(QCryptoCipher *cipher,
const void *in,
void *out,
size_t len,
Error **errp)
{
QCryptoCipherGcrypt *ctx = cipher->opaque;
gcry_error_t err;
if (len % ctx->blocksize) {
error_setg(errp, "Length %zu must be a multiple of block size %zu",
len, ctx->blocksize);
return -1;
}
#ifdef CONFIG_QEMU_PRIVATE_XTS
if (cipher->mode == QCRYPTO_CIPHER_MODE_XTS) {
xts_decrypt(ctx->handle, ctx->tweakhandle,
qcrypto_gcrypt_xts_encrypt,
qcrypto_gcrypt_xts_decrypt,
ctx->iv, len, out, in);
return 0;
}
#endif
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_cipher_setiv(QCryptoCipher *cipher,
const uint8_t *iv, size_t niv,
Error **errp)
{
QCryptoCipherGcrypt *ctx = cipher->opaque;
gcry_error_t err;
if (niv != ctx->blocksize) {
error_setg(errp, "Expected IV size %zu not %zu",
ctx->blocksize, niv);
return -1;
}
#ifdef CONFIG_QEMU_PRIVATE_XTS
if (ctx->iv) {
memcpy(ctx->iv, iv, niv);
return 0;
}
#endif
if (cipher->mode == QCRYPTO_CIPHER_MODE_CTR) {
err = gcry_cipher_setctr(ctx->handle, iv, niv);
if (err != 0) {
error_setg(errp, "Cannot set Counter: %s",
gcry_strerror(err));
return -1;
}
} else {
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 struct QCryptoCipherDriver qcrypto_cipher_lib_driver = {
.cipher_encrypt = qcrypto_gcrypt_cipher_encrypt,
.cipher_decrypt = qcrypto_gcrypt_cipher_decrypt,
.cipher_setiv = qcrypto_gcrypt_cipher_setiv,
.cipher_free = qcrypto_gcrypt_cipher_ctx_free,
};