303 lines
9 KiB
C++
303 lines
9 KiB
C++
/*
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* QEMU Crypto cipher built-in 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 2.1 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 "crypto/aes.h"
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typedef struct QCryptoCipherBuiltinAESContext QCryptoCipherBuiltinAESContext;
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struct QCryptoCipherBuiltinAESContext {
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AES_KEY enc;
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AES_KEY dec;
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};
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typedef struct QCryptoCipherBuiltinAES QCryptoCipherBuiltinAES;
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struct QCryptoCipherBuiltinAES {
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QCryptoCipher base;
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QCryptoCipherBuiltinAESContext key;
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uint8_t iv[AES_BLOCK_SIZE];
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};
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static inline bool qcrypto_length_check(size_t len, size_t blocksize,
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Error **errp)
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{
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if (unlikely(len & (blocksize - 1))) {
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error_setg(errp, "Length %zu must be a multiple of block size %zu",
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len, blocksize);
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return false;
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}
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return true;
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}
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static void qcrypto_cipher_ctx_free(QCryptoCipher *cipher)
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{
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g_free(cipher);
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}
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static int qcrypto_cipher_no_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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error_setg(errp, "Setting IV is not supported");
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return -1;
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}
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static void do_aes_encrypt_ecb(const void *vctx,
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size_t len,
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uint8_t *out,
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const uint8_t *in)
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{
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const QCryptoCipherBuiltinAESContext *ctx = vctx;
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/* We have already verified that len % AES_BLOCK_SIZE == 0. */
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while (len) {
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AES_encrypt(in, out, &ctx->enc);
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in += AES_BLOCK_SIZE;
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out += AES_BLOCK_SIZE;
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len -= AES_BLOCK_SIZE;
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}
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}
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static void do_aes_decrypt_ecb(const void *vctx,
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size_t len,
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uint8_t *out,
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const uint8_t *in)
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{
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const QCryptoCipherBuiltinAESContext *ctx = vctx;
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/* We have already verified that len % AES_BLOCK_SIZE == 0. */
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while (len) {
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AES_decrypt(in, out, &ctx->dec);
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in += AES_BLOCK_SIZE;
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out += AES_BLOCK_SIZE;
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len -= AES_BLOCK_SIZE;
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}
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}
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static void do_aes_encrypt_cbc(const AES_KEY *key,
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size_t len,
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uint8_t *out,
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const uint8_t *in,
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uint8_t *ivec)
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{
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uint8_t tmp[AES_BLOCK_SIZE];
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size_t n;
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/* We have already verified that len % AES_BLOCK_SIZE == 0. */
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while (len) {
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for (n = 0; n < AES_BLOCK_SIZE; ++n) {
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tmp[n] = in[n] ^ ivec[n];
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}
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AES_encrypt(tmp, out, key);
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memcpy(ivec, out, AES_BLOCK_SIZE);
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len -= AES_BLOCK_SIZE;
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in += AES_BLOCK_SIZE;
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out += AES_BLOCK_SIZE;
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}
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}
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static void do_aes_decrypt_cbc(const AES_KEY *key,
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size_t len,
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uint8_t *out,
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const uint8_t *in,
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uint8_t *ivec)
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{
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uint8_t tmp[AES_BLOCK_SIZE];
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size_t n;
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/* We have already verified that len % AES_BLOCK_SIZE == 0. */
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while (len) {
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memcpy(tmp, in, AES_BLOCK_SIZE);
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AES_decrypt(in, out, key);
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for (n = 0; n < AES_BLOCK_SIZE; ++n) {
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out[n] ^= ivec[n];
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}
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memcpy(ivec, tmp, AES_BLOCK_SIZE);
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len -= AES_BLOCK_SIZE;
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in += AES_BLOCK_SIZE;
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out += AES_BLOCK_SIZE;
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}
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}
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static int qcrypto_cipher_aes_encrypt_ecb(QCryptoCipher *cipher,
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const void *in, void *out,
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size_t len, Error **errp)
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{
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QCryptoCipherBuiltinAES *ctx
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= container_of(cipher, QCryptoCipherBuiltinAES, base);
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if (!qcrypto_length_check(len, AES_BLOCK_SIZE, errp)) {
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return -1;
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}
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do_aes_encrypt_ecb(&ctx->key, len, out, in);
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return 0;
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}
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static int qcrypto_cipher_aes_decrypt_ecb(QCryptoCipher *cipher,
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const void *in, void *out,
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size_t len, Error **errp)
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{
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QCryptoCipherBuiltinAES *ctx
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= container_of(cipher, QCryptoCipherBuiltinAES, base);
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if (!qcrypto_length_check(len, AES_BLOCK_SIZE, errp)) {
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return -1;
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}
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do_aes_decrypt_ecb(&ctx->key, len, out, in);
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return 0;
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}
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static int qcrypto_cipher_aes_encrypt_cbc(QCryptoCipher *cipher,
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const void *in, void *out,
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size_t len, Error **errp)
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{
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QCryptoCipherBuiltinAES *ctx
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= container_of(cipher, QCryptoCipherBuiltinAES, base);
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if (!qcrypto_length_check(len, AES_BLOCK_SIZE, errp)) {
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return -1;
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}
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do_aes_encrypt_cbc(&ctx->key.enc, len, out, in, ctx->iv);
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return 0;
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}
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static int qcrypto_cipher_aes_decrypt_cbc(QCryptoCipher *cipher,
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const void *in, void *out,
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size_t len, Error **errp)
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{
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QCryptoCipherBuiltinAES *ctx
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= container_of(cipher, QCryptoCipherBuiltinAES, base);
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if (!qcrypto_length_check(len, AES_BLOCK_SIZE, errp)) {
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return -1;
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}
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do_aes_decrypt_cbc(&ctx->key.dec, len, out, in, ctx->iv);
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return 0;
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}
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static int qcrypto_cipher_aes_setiv(QCryptoCipher *cipher, const uint8_t *iv,
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size_t niv, Error **errp)
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{
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QCryptoCipherBuiltinAES *ctx
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= container_of(cipher, QCryptoCipherBuiltinAES, base);
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if (niv != AES_BLOCK_SIZE) {
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error_setg(errp, "IV must be %d bytes not %zu",
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AES_BLOCK_SIZE, niv);
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return -1;
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}
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memcpy(ctx->iv, iv, AES_BLOCK_SIZE);
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return 0;
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}
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static const struct QCryptoCipherDriver qcrypto_cipher_aes_driver_ecb = {
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.cipher_encrypt = qcrypto_cipher_aes_encrypt_ecb,
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.cipher_decrypt = qcrypto_cipher_aes_decrypt_ecb,
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.cipher_setiv = qcrypto_cipher_no_setiv,
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.cipher_free = qcrypto_cipher_ctx_free,
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};
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static const struct QCryptoCipherDriver qcrypto_cipher_aes_driver_cbc = {
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.cipher_encrypt = qcrypto_cipher_aes_encrypt_cbc,
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.cipher_decrypt = qcrypto_cipher_aes_decrypt_cbc,
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.cipher_setiv = qcrypto_cipher_aes_setiv,
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.cipher_free = qcrypto_cipher_ctx_free,
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};
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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_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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switch (mode) {
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case QCRYPTO_CIPHER_MODE_ECB:
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case QCRYPTO_CIPHER_MODE_CBC:
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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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break;
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default:
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return false;
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}
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}
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static QCryptoCipher *qcrypto_cipher_ctx_new(QCryptoCipherAlgorithm alg,
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QCryptoCipherMode mode,
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const uint8_t *key,
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size_t nkey,
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Error **errp)
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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_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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{
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QCryptoCipherBuiltinAES *ctx;
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const QCryptoCipherDriver *drv;
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switch (mode) {
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case QCRYPTO_CIPHER_MODE_ECB:
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drv = &qcrypto_cipher_aes_driver_ecb;
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break;
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case QCRYPTO_CIPHER_MODE_CBC:
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drv = &qcrypto_cipher_aes_driver_cbc;
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break;
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default:
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goto bad_mode;
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}
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ctx = g_new0(QCryptoCipherBuiltinAES, 1);
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ctx->base.driver = drv;
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if (AES_set_encrypt_key(key, nkey * 8, &ctx->key.enc)) {
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error_setg(errp, "Failed to set encryption key");
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goto error;
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}
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if (AES_set_decrypt_key(key, nkey * 8, &ctx->key.dec)) {
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error_setg(errp, "Failed to set decryption key");
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goto error;
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}
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return &ctx->base;
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error:
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g_free(ctx);
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return NULL;
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}
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default:
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error_setg(errp,
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"Unsupported cipher algorithm %s",
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QCryptoCipherAlgorithm_str(alg));
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return NULL;
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}
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bad_mode:
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error_setg(errp, "Unsupported cipher mode %s",
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QCryptoCipherMode_str(mode));
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return NULL;
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}
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