383 lines
11 KiB
C
383 lines
11 KiB
C
/*
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* QEMU Crypto cipher libgcrypt algorithms
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*
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* Copyright (c) 2015 Red Hat, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include "qemu/osdep.h"
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#include "crypto/xts.h"
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#include <gcrypt.h>
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bool qcrypto_cipher_supports(QCryptoCipherAlgorithm alg,
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QCryptoCipherMode mode)
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{
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switch (alg) {
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case QCRYPTO_CIPHER_ALG_DES_RFB:
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case QCRYPTO_CIPHER_ALG_3DES:
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case QCRYPTO_CIPHER_ALG_AES_128:
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case QCRYPTO_CIPHER_ALG_AES_192:
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case QCRYPTO_CIPHER_ALG_AES_256:
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case QCRYPTO_CIPHER_ALG_CAST5_128:
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case QCRYPTO_CIPHER_ALG_SERPENT_128:
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case QCRYPTO_CIPHER_ALG_SERPENT_192:
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case QCRYPTO_CIPHER_ALG_SERPENT_256:
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case QCRYPTO_CIPHER_ALG_TWOFISH_128:
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case QCRYPTO_CIPHER_ALG_TWOFISH_256:
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break;
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default:
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return false;
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}
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switch (mode) {
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case QCRYPTO_CIPHER_MODE_ECB:
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case QCRYPTO_CIPHER_MODE_CBC:
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case QCRYPTO_CIPHER_MODE_XTS:
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case QCRYPTO_CIPHER_MODE_CTR:
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return true;
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default:
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return false;
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}
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}
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typedef struct QCryptoCipherGcrypt QCryptoCipherGcrypt;
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struct QCryptoCipherGcrypt {
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gcry_cipher_hd_t handle;
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gcry_cipher_hd_t tweakhandle;
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size_t blocksize;
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/* Initialization vector or Counter */
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uint8_t *iv;
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};
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QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm alg,
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QCryptoCipherMode mode,
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const uint8_t *key, size_t nkey,
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Error **errp)
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{
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QCryptoCipher *cipher;
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QCryptoCipherGcrypt *ctx;
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gcry_error_t err;
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int gcryalg, gcrymode;
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switch (mode) {
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case QCRYPTO_CIPHER_MODE_ECB:
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case QCRYPTO_CIPHER_MODE_XTS:
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gcrymode = GCRY_CIPHER_MODE_ECB;
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break;
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case QCRYPTO_CIPHER_MODE_CBC:
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gcrymode = GCRY_CIPHER_MODE_CBC;
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break;
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case QCRYPTO_CIPHER_MODE_CTR:
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gcrymode = GCRY_CIPHER_MODE_CTR;
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break;
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default:
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error_setg(errp, "Unsupported cipher mode %s",
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QCryptoCipherMode_lookup[mode]);
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return NULL;
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}
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if (!qcrypto_cipher_validate_key_length(alg, mode, nkey, errp)) {
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return NULL;
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}
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switch (alg) {
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case QCRYPTO_CIPHER_ALG_DES_RFB:
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gcryalg = GCRY_CIPHER_DES;
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break;
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case QCRYPTO_CIPHER_ALG_3DES:
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gcryalg = GCRY_CIPHER_3DES;
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break;
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case QCRYPTO_CIPHER_ALG_AES_128:
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gcryalg = GCRY_CIPHER_AES128;
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break;
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case QCRYPTO_CIPHER_ALG_AES_192:
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gcryalg = GCRY_CIPHER_AES192;
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break;
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case QCRYPTO_CIPHER_ALG_AES_256:
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gcryalg = GCRY_CIPHER_AES256;
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break;
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case QCRYPTO_CIPHER_ALG_CAST5_128:
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gcryalg = GCRY_CIPHER_CAST5;
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break;
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case QCRYPTO_CIPHER_ALG_SERPENT_128:
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gcryalg = GCRY_CIPHER_SERPENT128;
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break;
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case QCRYPTO_CIPHER_ALG_SERPENT_192:
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gcryalg = GCRY_CIPHER_SERPENT192;
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break;
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case QCRYPTO_CIPHER_ALG_SERPENT_256:
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gcryalg = GCRY_CIPHER_SERPENT256;
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break;
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case QCRYPTO_CIPHER_ALG_TWOFISH_128:
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gcryalg = GCRY_CIPHER_TWOFISH128;
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break;
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case QCRYPTO_CIPHER_ALG_TWOFISH_256:
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gcryalg = GCRY_CIPHER_TWOFISH;
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break;
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default:
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error_setg(errp, "Unsupported cipher algorithm %s",
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QCryptoCipherAlgorithm_lookup[alg]);
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return NULL;
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}
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cipher = g_new0(QCryptoCipher, 1);
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cipher->alg = alg;
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cipher->mode = mode;
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ctx = g_new0(QCryptoCipherGcrypt, 1);
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err = gcry_cipher_open(&ctx->handle, gcryalg, gcrymode, 0);
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if (err != 0) {
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error_setg(errp, "Cannot initialize cipher: %s",
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gcry_strerror(err));
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goto error;
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}
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if (cipher->mode == QCRYPTO_CIPHER_MODE_XTS) {
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err = gcry_cipher_open(&ctx->tweakhandle, gcryalg, gcrymode, 0);
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if (err != 0) {
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error_setg(errp, "Cannot initialize cipher: %s",
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gcry_strerror(err));
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goto error;
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}
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}
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if (cipher->alg == QCRYPTO_CIPHER_ALG_DES_RFB) {
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/* We're using standard DES cipher from gcrypt, so we need
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* to munge the key so that the results are the same as the
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* bizarre RFB variant of DES :-)
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*/
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uint8_t *rfbkey = qcrypto_cipher_munge_des_rfb_key(key, nkey);
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err = gcry_cipher_setkey(ctx->handle, rfbkey, nkey);
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g_free(rfbkey);
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ctx->blocksize = 8;
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} else {
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if (cipher->mode == QCRYPTO_CIPHER_MODE_XTS) {
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nkey /= 2;
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err = gcry_cipher_setkey(ctx->handle, key, nkey);
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if (err != 0) {
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error_setg(errp, "Cannot set key: %s",
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gcry_strerror(err));
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goto error;
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}
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err = gcry_cipher_setkey(ctx->tweakhandle, key + nkey, nkey);
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} else {
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err = gcry_cipher_setkey(ctx->handle, key, nkey);
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}
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if (err != 0) {
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error_setg(errp, "Cannot set key: %s",
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gcry_strerror(err));
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goto error;
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}
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switch (cipher->alg) {
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case QCRYPTO_CIPHER_ALG_AES_128:
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case QCRYPTO_CIPHER_ALG_AES_192:
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case QCRYPTO_CIPHER_ALG_AES_256:
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case QCRYPTO_CIPHER_ALG_SERPENT_128:
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case QCRYPTO_CIPHER_ALG_SERPENT_192:
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case QCRYPTO_CIPHER_ALG_SERPENT_256:
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case QCRYPTO_CIPHER_ALG_TWOFISH_128:
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case QCRYPTO_CIPHER_ALG_TWOFISH_256:
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ctx->blocksize = 16;
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break;
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case QCRYPTO_CIPHER_ALG_3DES:
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case QCRYPTO_CIPHER_ALG_CAST5_128:
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ctx->blocksize = 8;
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break;
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default:
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g_assert_not_reached();
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}
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}
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if (cipher->mode == QCRYPTO_CIPHER_MODE_XTS) {
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if (ctx->blocksize != XTS_BLOCK_SIZE) {
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error_setg(errp,
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"Cipher block size %zu must equal XTS block size %d",
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ctx->blocksize, XTS_BLOCK_SIZE);
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goto error;
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}
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ctx->iv = g_new0(uint8_t, ctx->blocksize);
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}
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cipher->opaque = ctx;
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return cipher;
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error:
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gcry_cipher_close(ctx->handle);
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if (cipher->mode == QCRYPTO_CIPHER_MODE_XTS) {
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gcry_cipher_close(ctx->tweakhandle);
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}
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g_free(ctx);
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g_free(cipher);
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return NULL;
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}
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void qcrypto_cipher_free(QCryptoCipher *cipher)
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{
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QCryptoCipherGcrypt *ctx;
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if (!cipher) {
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return;
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}
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ctx = cipher->opaque;
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gcry_cipher_close(ctx->handle);
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if (cipher->mode == QCRYPTO_CIPHER_MODE_XTS) {
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gcry_cipher_close(ctx->tweakhandle);
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}
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g_free(ctx->iv);
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g_free(ctx);
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g_free(cipher);
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}
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static void qcrypto_gcrypt_xts_encrypt(const void *ctx,
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size_t length,
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uint8_t *dst,
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const uint8_t *src)
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{
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gcry_error_t err;
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err = gcry_cipher_encrypt((gcry_cipher_hd_t)ctx, dst, length, src, length);
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g_assert(err == 0);
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}
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static void qcrypto_gcrypt_xts_decrypt(const void *ctx,
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size_t length,
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uint8_t *dst,
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const uint8_t *src)
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{
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gcry_error_t err;
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err = gcry_cipher_decrypt((gcry_cipher_hd_t)ctx, dst, length, src, length);
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g_assert(err == 0);
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}
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int qcrypto_cipher_encrypt(QCryptoCipher *cipher,
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const void *in,
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void *out,
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size_t len,
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Error **errp)
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{
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QCryptoCipherGcrypt *ctx = cipher->opaque;
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gcry_error_t err;
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if (len % ctx->blocksize) {
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error_setg(errp, "Length %zu must be a multiple of block size %zu",
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len, ctx->blocksize);
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return -1;
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}
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if (cipher->mode == QCRYPTO_CIPHER_MODE_XTS) {
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xts_encrypt(ctx->handle, ctx->tweakhandle,
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qcrypto_gcrypt_xts_encrypt,
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qcrypto_gcrypt_xts_decrypt,
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ctx->iv, len, out, in);
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} else {
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err = gcry_cipher_encrypt(ctx->handle,
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out, len,
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in, len);
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if (err != 0) {
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error_setg(errp, "Cannot encrypt data: %s",
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gcry_strerror(err));
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return -1;
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}
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}
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return 0;
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}
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int qcrypto_cipher_decrypt(QCryptoCipher *cipher,
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const void *in,
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void *out,
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size_t len,
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Error **errp)
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{
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QCryptoCipherGcrypt *ctx = cipher->opaque;
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gcry_error_t err;
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if (len % ctx->blocksize) {
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error_setg(errp, "Length %zu must be a multiple of block size %zu",
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len, ctx->blocksize);
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return -1;
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}
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if (cipher->mode == QCRYPTO_CIPHER_MODE_XTS) {
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xts_decrypt(ctx->handle, ctx->tweakhandle,
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qcrypto_gcrypt_xts_encrypt,
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qcrypto_gcrypt_xts_decrypt,
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ctx->iv, len, out, in);
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} else {
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err = gcry_cipher_decrypt(ctx->handle,
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out, len,
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in, len);
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if (err != 0) {
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error_setg(errp, "Cannot decrypt data: %s",
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gcry_strerror(err));
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return -1;
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}
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}
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return 0;
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}
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int qcrypto_cipher_setiv(QCryptoCipher *cipher,
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const uint8_t *iv, size_t niv,
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Error **errp)
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{
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QCryptoCipherGcrypt *ctx = cipher->opaque;
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gcry_error_t err;
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if (niv != ctx->blocksize) {
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error_setg(errp, "Expected IV size %zu not %zu",
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ctx->blocksize, niv);
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return -1;
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}
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if (ctx->iv) {
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memcpy(ctx->iv, iv, niv);
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} else {
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if (cipher->mode == QCRYPTO_CIPHER_MODE_CTR) {
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err = gcry_cipher_setctr(ctx->handle, iv, niv);
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if (err != 0) {
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error_setg(errp, "Cannot set Counter: %s",
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gcry_strerror(err));
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return -1;
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}
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} else {
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gcry_cipher_reset(ctx->handle);
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err = gcry_cipher_setiv(ctx->handle, iv, niv);
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if (err != 0) {
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error_setg(errp, "Cannot set IV: %s",
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gcry_strerror(err));
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return -1;
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}
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}
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}
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return 0;
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}
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