Introduce CTR mode support for the cipher APIs. CTR mode uses a counter rather than a traditional IV. The counter has additional properties, including a nonce and initial counter block. We reuse the ctx->iv as the counter for conveniences. Both libgcrypt and nettle are support CTR mode, the cipher-builtin doesn't support yet. Signed-off-by: Gonglei <arei.gonglei@huawei.com> Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
159 lines
4.5 KiB
C
159 lines
4.5 KiB
C
/*
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* QEMU Crypto cipher 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 "qapi/error.h"
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#include "crypto/cipher.h"
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static size_t alg_key_len[QCRYPTO_CIPHER_ALG__MAX] = {
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[QCRYPTO_CIPHER_ALG_AES_128] = 16,
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[QCRYPTO_CIPHER_ALG_AES_192] = 24,
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[QCRYPTO_CIPHER_ALG_AES_256] = 32,
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[QCRYPTO_CIPHER_ALG_DES_RFB] = 8,
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[QCRYPTO_CIPHER_ALG_CAST5_128] = 16,
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[QCRYPTO_CIPHER_ALG_SERPENT_128] = 16,
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[QCRYPTO_CIPHER_ALG_SERPENT_192] = 24,
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[QCRYPTO_CIPHER_ALG_SERPENT_256] = 32,
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[QCRYPTO_CIPHER_ALG_TWOFISH_128] = 16,
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[QCRYPTO_CIPHER_ALG_TWOFISH_192] = 24,
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[QCRYPTO_CIPHER_ALG_TWOFISH_256] = 32,
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};
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static size_t alg_block_len[QCRYPTO_CIPHER_ALG__MAX] = {
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[QCRYPTO_CIPHER_ALG_AES_128] = 16,
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[QCRYPTO_CIPHER_ALG_AES_192] = 16,
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[QCRYPTO_CIPHER_ALG_AES_256] = 16,
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[QCRYPTO_CIPHER_ALG_DES_RFB] = 8,
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[QCRYPTO_CIPHER_ALG_CAST5_128] = 8,
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[QCRYPTO_CIPHER_ALG_SERPENT_128] = 16,
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[QCRYPTO_CIPHER_ALG_SERPENT_192] = 16,
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[QCRYPTO_CIPHER_ALG_SERPENT_256] = 16,
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[QCRYPTO_CIPHER_ALG_TWOFISH_128] = 16,
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[QCRYPTO_CIPHER_ALG_TWOFISH_192] = 16,
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[QCRYPTO_CIPHER_ALG_TWOFISH_256] = 16,
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};
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static bool mode_need_iv[QCRYPTO_CIPHER_MODE__MAX] = {
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[QCRYPTO_CIPHER_MODE_ECB] = false,
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[QCRYPTO_CIPHER_MODE_CBC] = true,
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[QCRYPTO_CIPHER_MODE_XTS] = true,
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[QCRYPTO_CIPHER_MODE_CTR] = true,
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};
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size_t qcrypto_cipher_get_block_len(QCryptoCipherAlgorithm alg)
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{
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if (alg >= G_N_ELEMENTS(alg_key_len)) {
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return 0;
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}
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return alg_block_len[alg];
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}
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size_t qcrypto_cipher_get_key_len(QCryptoCipherAlgorithm alg)
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{
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if (alg >= G_N_ELEMENTS(alg_key_len)) {
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return 0;
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}
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return alg_key_len[alg];
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}
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size_t qcrypto_cipher_get_iv_len(QCryptoCipherAlgorithm alg,
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QCryptoCipherMode mode)
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{
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if (alg >= G_N_ELEMENTS(alg_block_len)) {
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return 0;
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}
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if (mode >= G_N_ELEMENTS(mode_need_iv)) {
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return 0;
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}
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if (mode_need_iv[mode]) {
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return alg_block_len[alg];
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}
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return 0;
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}
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static bool
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qcrypto_cipher_validate_key_length(QCryptoCipherAlgorithm alg,
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QCryptoCipherMode mode,
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size_t nkey,
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Error **errp)
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{
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if ((unsigned)alg >= QCRYPTO_CIPHER_ALG__MAX) {
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error_setg(errp, "Cipher algorithm %d out of range",
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alg);
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return false;
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}
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if (mode == QCRYPTO_CIPHER_MODE_XTS) {
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if (alg == QCRYPTO_CIPHER_ALG_DES_RFB) {
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error_setg(errp, "XTS mode not compatible with DES-RFB");
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return false;
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}
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if (nkey % 2) {
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error_setg(errp, "XTS cipher key length should be a multiple of 2");
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return false;
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}
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if (alg_key_len[alg] != (nkey / 2)) {
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error_setg(errp, "Cipher key length %zu should be %zu",
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nkey, alg_key_len[alg] * 2);
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return false;
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}
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} else {
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if (alg_key_len[alg] != nkey) {
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error_setg(errp, "Cipher key length %zu should be %zu",
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nkey, alg_key_len[alg]);
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return false;
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}
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}
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return true;
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}
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#if defined(CONFIG_GCRYPT) || defined(CONFIG_NETTLE)
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static uint8_t *
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qcrypto_cipher_munge_des_rfb_key(const uint8_t *key,
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size_t nkey)
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{
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uint8_t *ret = g_new0(uint8_t, nkey);
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size_t i;
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for (i = 0; i < nkey; i++) {
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uint8_t r = key[i];
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r = (r & 0xf0) >> 4 | (r & 0x0f) << 4;
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r = (r & 0xcc) >> 2 | (r & 0x33) << 2;
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r = (r & 0xaa) >> 1 | (r & 0x55) << 1;
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ret[i] = r;
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}
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return ret;
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}
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#endif /* CONFIG_GCRYPT || CONFIG_NETTLE */
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#ifdef CONFIG_GCRYPT
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#include "crypto/cipher-gcrypt.c"
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#elif defined CONFIG_NETTLE
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#include "crypto/cipher-nettle.c"
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#else
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#include "crypto/cipher-builtin.c"
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#endif
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