aes-decrypt.c
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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (c) 2019, softathome
*/
#ifndef USE_HOSTCC
#include <common.h>
#include <malloc.h>
#endif
#include <image.h>
#include <uboot_aes.h>
int image_aes_decrypt(struct image_cipher_info *info,
const void *cipher, size_t cipher_len,
void **data, size_t *size)
{
#ifndef USE_HOSTCC
unsigned char key_exp[AES256_EXPAND_KEY_LENGTH];
unsigned int aes_blocks, key_len = info->cipher->key_len;
*data = malloc(cipher_len);
if (!*data) {
printf("Can't allocate memory to decrypt\n");
return -ENOMEM;
}
*size = info->size_unciphered;
memcpy(&key_exp[0], info->key, key_len);
/* First we expand the key. */
aes_expand_key((u8 *)info->key, key_len, key_exp);
/* Calculate the number of AES blocks to encrypt. */
aes_blocks = DIV_ROUND_UP(cipher_len, AES_BLOCK_LENGTH);
aes_cbc_decrypt_blocks(key_len, key_exp, (u8 *)info->iv,
(u8 *)cipher, *data, aes_blocks);
#endif
return 0;
}