hal/accelerator/aes_alt.c

/*
*  FIPS-197 compliant AES implementation
*
*  Copyright The Mbed TLS Contributors
*  Copyright (C) 2021, STMicroelectronics, All Rights Reserved
*  SPDX-License-Identifier: Apache-2.0
*
*  Licensed under the Apache License, Version 2.0 (the "License"); you may
*  not use this file except in compliance with the License.
*  You may obtain a copy of the License at
*
*  http://www.apache.org/licenses/LICENSE-2.0
*
*  Unless required by applicable law or agreed to in writing, software
*  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
*  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
*  See the License for the specific language governing permissions and
*  limitations under the License.
*
*  This file implements ST AES HW services based on API from mbed TLS
*
*  The AES block cipher was designed by Vincent Rijmen and Joan Daemen.
*
*  http://csrc.nist.gov/encryption/aes/rijndael/Rijndael.pdf
*  http://csrc.nist.gov/publications/fips/fips197/fips-197.pdf
*/


/* Includes ------------------------------------------------------------------*/
#include "mbedtls/aes.h"

#if defined(MBEDTLS_AES_C)
#if defined(MBEDTLS_AES_ALT)
#include <string.h>
#include "mbedtls/platform.h"
#include "mbedtls/platform_util.h"
#include "mbedtls/error.h"

/* Parameter validation macros - mbedtls/platform_util.h has deprecated them */
#define AES_VALIDATE_RET( cond ) do { } while(0)
#define AES_VALIDATE( cond ) do { } while(0)

/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
#define ST_AES_TIMEOUT     0xFFU   /* 255 ms timeout for the crypto processor */
#define ST_AES_NO_ALGO     0xFFFFU /* any algo is programmed */

/* Private macro -------------------------------------------------------------*/
#define SWAP_B8_TO_B32(b32,b8,i)                         \
{                                                        \
  (b32) = ( (uint32_t) (b8)[(i) + 3]       )             \
        | ( (uint32_t) (b8)[(i) + 2] <<  8 )             \
        | ( (uint32_t) (b8)[(i) + 1] << 16 )             \
        | ( (uint32_t) (b8)[(i)    ] << 24 );            \
}

#define SWAP_B32_TO_B8(b32,b8,i)                                 \
{                                                                \
  (b8)[(i) + 3] = (unsigned char) ( ( (b32)       ) & 0xFF );    \
  (b8)[(i) + 2] = (unsigned char) ( ( (b32) >>  8 ) & 0xFF );    \
  (b8)[(i) + 1] = (unsigned char) ( ( (b32) >> 16 ) & 0xFF );    \
  (b8)[(i)    ] = (unsigned char) ( ( (b32) >> 24 ) & 0xFF );    \
}

/* Private variables ---------------------------------------------------------*/
/* Private function prototypes -----------------------------------------------*/
/* Private functions ---------------------------------------------------------*/

static int aes_set_key(mbedtls_aes_context *ctx,
                       const unsigned char *key,
                       unsigned int keybits)
{
    AES_VALIDATE_RET( ctx != NULL );

    switch (keybits) {
#if defined(GENERATOR_HW_CRYPTO_DPA_SUPPORTED) && defined(HW_CRYPTO_DPA_AES)
        case 0:
            /* implicit request for using HUK */
            break;
#endif
        case 128:
            ctx->hcryp_aes.Init.KeySize = CRYP_KEYSIZE_128B;;

            SWAP_B8_TO_B32(ctx->aes_key[0],key,0);
            SWAP_B8_TO_B32(ctx->aes_key[1],key,4);
            SWAP_B8_TO_B32(ctx->aes_key[2],key,8);
            SWAP_B8_TO_B32(ctx->aes_key[3],key,12);
            break;

        case 192:
            return (MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED);

        case 256:
            ctx->hcryp_aes.Init.KeySize = CRYP_KEYSIZE_256B;

            SWAP_B8_TO_B32(ctx->aes_key[0],key,0);
            SWAP_B8_TO_B32(ctx->aes_key[1],key,4);
            SWAP_B8_TO_B32(ctx->aes_key[2],key,8);
            SWAP_B8_TO_B32(ctx->aes_key[3],key,12);
            SWAP_B8_TO_B32(ctx->aes_key[4],key,16);
            SWAP_B8_TO_B32(ctx->aes_key[5],key,20);
            SWAP_B8_TO_B32(ctx->aes_key[6],key,24);
            SWAP_B8_TO_B32(ctx->aes_key[7],key,28);
            break;

        default :
            return (MBEDTLS_ERR_AES_INVALID_KEY_LENGTH);
    }
#if defined(GENERATOR_HW_CRYPTO_DPA_SUPPORTED) && defined(HW_CRYPTO_DPA_AES)
    ctx->hcryp_aes.Instance = SAES;
#else
    ctx->hcryp_aes.Instance = AES;
#endif
#if defined(STM32L5)
    ctx->hcryp_aes.Init.DataType = CRYP_DATATYPE_8B;
#else
    ctx->hcryp_aes.Init.DataType = CRYP_BYTE_SWAP;
#endif
    ctx->hcryp_aes.Init.DataWidthUnit = CRYP_DATAWIDTHUNIT_BYTE;
    ctx->hcryp_aes.Init.pKey = ctx->aes_key;

#if defined(GENERATOR_HW_CRYPTO_DPA_SUPPORTED) && defined(HW_CRYPTO_DPA_AES)
    if ( 0 == keybits )
    {
        ctx->hcryp_aes.Init.KeyMode = CRYP_KEYMODE_NORMAL;
        ctx->hcryp_aes.Init.KeyProtection = CRYP_KEYSEL_HW;
    }
    else
    {
        ctx->hcryp_aes.Init.KeyMode = CRYP_KEYMODE_NORMAL;
        ctx->hcryp_aes.Init.KeyProtection = CRYP_KEYSEL_NORMAL;
    }
#endif

    /* Initializes the CRYP peripheral */
    if (HAL_CRYP_DeInit(&ctx->hcryp_aes) != HAL_OK) {
        return (MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED);
    }

#if defined(GENERATOR_HW_CRYPTO_DPA_SUPPORTED) && defined(HW_CRYPTO_DPA_AES)
    /* Enable SAES clock */
    __HAL_RCC_SAES_CLK_ENABLE();
#else
    /* Enable AES clock */
    __HAL_RCC_AES_CLK_ENABLE();
#endif

    if (HAL_CRYP_Init(&ctx->hcryp_aes) != HAL_OK) {
        return (MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED);
    }

    /* allow multi-instance of CRYP use: save context for CRYP HW module CR */
    ctx->ctx_save_cr = ctx->hcryp_aes.Instance->CR;

    return (0);
}

/* Implementation that should never be optimized out by the compiler */
static void mbedtls_zeroize(void *v, size_t n)
{
    volatile unsigned char *p = (unsigned char *)v;
    while (n--) {
        *p++ = 0;
    }
}

void mbedtls_aes_init(mbedtls_aes_context *ctx)
{
    AES_VALIDATE( ctx != NULL );

    memset(ctx, 0, sizeof(mbedtls_aes_context));

#if defined(STM32L5)
#else
    ctx->hcryp_aes.Init.Algorithm  = ST_AES_NO_ALGO;
#endif
}


void mbedtls_aes_free(mbedtls_aes_context *ctx)
{
    if (ctx == NULL) {
        return;
    }

    mbedtls_zeroize(ctx, sizeof(mbedtls_aes_context));
}

#if defined(MBEDTLS_CIPHER_MODE_XTS)
void mbedtls_aes_xts_init( mbedtls_aes_xts_context *ctx )
{
    AES_VALIDATE( ctx != NULL );

    mbedtls_aes_init( &ctx->crypt );
    mbedtls_aes_init( &ctx->tweak );
}

void mbedtls_aes_xts_free( mbedtls_aes_xts_context *ctx )
{
    if( ctx == NULL )
        return;

    mbedtls_aes_free( &ctx->crypt );
    mbedtls_aes_free( &ctx->tweak );
}
#endif /* MBEDTLS_CIPHER_MODE_XTS */

/*
 * AES key schedule (encryption)
 */
int mbedtls_aes_setkey_enc(mbedtls_aes_context *ctx, const unsigned char *key,
                           unsigned int keybits)
{
    return (aes_set_key(ctx, key, keybits));
}

/*
 * AES key schedule (decryption)
 */
int mbedtls_aes_setkey_dec(mbedtls_aes_context *ctx, const unsigned char *key,
                           unsigned int keybits)
{
    return (aes_set_key(ctx, key, keybits));
}

#if defined(MBEDTLS_CIPHER_MODE_XTS)
static int mbedtls_aes_xts_decode_keys( const unsigned char *key,
                                        unsigned int keybits,
                                        const unsigned char **key1,
                                        unsigned int *key1bits,
                                        const unsigned char **key2,
                                        unsigned int *key2bits )
{
    const unsigned int half_keybits = keybits / 2;
    const unsigned int half_keybytes = half_keybits / 8;

    switch( keybits )
    {
        case 256: break;
        case 512: break;
        default : return( MBEDTLS_ERR_AES_INVALID_KEY_LENGTH );
    }

    *key1bits = half_keybits;
    *key2bits = half_keybits;
    *key1 = &key[0];
    *key2 = &key[half_keybytes];

    return ( 0 );
}

int mbedtls_aes_xts_setkey_enc( mbedtls_aes_xts_context *ctx,
                                const unsigned char *key,
                                unsigned int keybits)
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
    const unsigned char *key1, *key2;
    unsigned int key1bits, key2bits;

    AES_VALIDATE_RET( ctx != NULL );
    AES_VALIDATE_RET( key != NULL );

    ret = mbedtls_aes_xts_decode_keys( key, keybits, &key1, &key1bits,
                                       &key2, &key2bits );
    if( ret != 0 )
        return( ret );

    /* Set the tweak key. Always set tweak key for the encryption mode. */
    ret = mbedtls_aes_setkey_enc( &ctx->tweak, key2, key2bits );
    if( ret != 0 )
        return( ret );

    /* Set crypt key for encryption. */
    return (mbedtls_aes_setkey_enc( &ctx->crypt, key1, key1bits ));
}

int mbedtls_aes_xts_setkey_dec( mbedtls_aes_xts_context *ctx,
                                const unsigned char *key,
                                unsigned int keybits)
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
    const unsigned char *key1, *key2;
    unsigned int key1bits, key2bits;

    AES_VALIDATE_RET( ctx != NULL );
    AES_VALIDATE_RET( key != NULL );

    ret = mbedtls_aes_xts_decode_keys( key, keybits, &key1, &key1bits,
                                       &key2, &key2bits );
    if( ret != 0 )
        return( ret );

    /* Set the tweak key. Always set tweak key for encryption. */
    ret = mbedtls_aes_setkey_enc( &ctx->tweak, key2, key2bits );
    if( ret != 0 )
        return( ret );

    /* Set crypt key for decryption. */
    return (mbedtls_aes_setkey_dec( &ctx->crypt, key1, key1bits ));
}
#endif /* MBEDTLS_CIPHER_MODE_XTS */

/*
 * AES-ECB block encryption/decryption
 */
int mbedtls_aes_crypt_ecb(mbedtls_aes_context *ctx,
                          int mode,
                          const unsigned char input[16],
                          unsigned char output[16])
{
    int ret;

    AES_VALIDATE_RET( ctx != NULL );
    AES_VALIDATE_RET( input != NULL );
    AES_VALIDATE_RET( output != NULL );
    AES_VALIDATE_RET( mode == MBEDTLS_AES_ENCRYPT ||
                      mode == MBEDTLS_AES_DECRYPT );

    /* allow multi-instance of CRYP use: restore context for CRYP hw module */
    ctx->hcryp_aes.Instance->CR = ctx->ctx_save_cr;

    /* Set the Algo if not configured till now */
    if (CRYP_AES_ECB != ctx->hcryp_aes.Init.Algorithm)
    {
        ctx->hcryp_aes.Init.Algorithm  = CRYP_AES_ECB;

        /* Configure the CRYP  */
        if (HAL_CRYP_SetConfig(&ctx->hcryp_aes, &ctx->hcryp_aes.Init) != HAL_OK)
            return MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED;
    }

    if (mode == MBEDTLS_AES_DECRYPT) { /* AES decryption */
        ret = mbedtls_internal_aes_decrypt(ctx, input, output);
        if( ret != 0 )
            return (ret);
    } else { /* AES encryption */
        ret = mbedtls_internal_aes_encrypt(ctx, input, output);
        if( ret != 0 )
            return (ret);
    }
    /* allow multi-instance of CRYP use: save context for CRYP HW module CR */
    ctx->ctx_save_cr = ctx->hcryp_aes.Instance->CR;

    return (0);
}

#if defined(MBEDTLS_CIPHER_MODE_CBC)
/*
 * AES-CBC buffer encryption/decryption
 */
static int st_cbc_restore_context(mbedtls_aes_context *ctx)
{
    /* allow multi-instance of CRYP use: restore context for CRYP hw module */
    ctx->hcryp_aes.Instance->CR = ctx->ctx_save_cr;

    /* Re-initialize AES processor with proper parameters
       and (re-)apply key and IV for multi context usecases */
    if (HAL_CRYP_DeInit(&ctx->hcryp_aes) != HAL_OK) {
        return (MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED);
    }

    if (HAL_CRYP_Init(&ctx->hcryp_aes) != HAL_OK) {
        return (MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED);
    }
    return (0);
}

int mbedtls_aes_crypt_cbc(mbedtls_aes_context *ctx,
                          int mode,
                          size_t length,
                          unsigned char iv[16],
                          const unsigned char *input,
                          unsigned char *output)
{
    __ALIGN_BEGIN static uint32_t iv_32B[4] __ALIGN_END;
    int ret = 0;

    AES_VALIDATE_RET( ctx != NULL );
    AES_VALIDATE_RET( mode == MBEDTLS_AES_ENCRYPT ||
                      mode == MBEDTLS_AES_DECRYPT );
    AES_VALIDATE_RET( iv != NULL );
    AES_VALIDATE_RET( input != NULL );
    AES_VALIDATE_RET( output != NULL );

    if (length % 16) {
        return (MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH);
    }

    ret = st_cbc_restore_context(ctx);
    if (ret != 0)
        return (ret);

    /* Set the Algo if not configured till now */
    if (CRYP_AES_CBC != ctx->hcryp_aes.Init.Algorithm)
    {
        ctx->hcryp_aes.Init.Algorithm  = CRYP_AES_CBC;
    }

    /* Set IV with invert endianness */
    SWAP_B8_TO_B32(iv_32B[0],iv,0);
    SWAP_B8_TO_B32(iv_32B[1],iv,4);
    SWAP_B8_TO_B32(iv_32B[2],iv,8);
    SWAP_B8_TO_B32(iv_32B[3],iv,12);

    ctx->hcryp_aes.Init.pInitVect = iv_32B;

    /* reconfigure the CRYP */
    if (HAL_CRYP_SetConfig(&ctx->hcryp_aes, &ctx->hcryp_aes.Init) != HAL_OK) {
        return (MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED);
    }

    if (mode == MBEDTLS_AES_DECRYPT) {
        if (HAL_CRYP_Decrypt(&ctx->hcryp_aes, (uint32_t *)input, length, (uint32_t *)output, ST_AES_TIMEOUT) != HAL_OK) {
            return (MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED);
        }

        /* Get IV vector for the next call */
        SWAP_B32_TO_B8(ctx->hcryp_aes.Instance->IVR3,iv,0);
        SWAP_B32_TO_B8(ctx->hcryp_aes.Instance->IVR2,iv,4);
        SWAP_B32_TO_B8(ctx->hcryp_aes.Instance->IVR1,iv,8);
        SWAP_B32_TO_B8(ctx->hcryp_aes.Instance->IVR0,iv,12);

    } else {
        if (HAL_CRYP_Encrypt(&ctx->hcryp_aes, (uint32_t *)input, length, (uint32_t *)output, ST_AES_TIMEOUT) != HAL_OK) {
            return (MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED);
        }

        /* current output is the IV vector for the next call */
        memcpy(iv, &output[length - 16], 16);
    }

    /* Save the internal IV vector for multi context purpose */
    ctx->ctx_save_cr = ctx->hcryp_aes.Instance->CR; // save here before overwritten
    ctx->hcryp_aes.Instance->CR &= ~AES_CR_EN;

    return (0);
}
#endif /* MBEDTLS_CIPHER_MODE_CBC */

#if defined(MBEDTLS_CIPHER_MODE_XTS)

/* Endianness with 64 bits values */
#ifndef GET_UINT64_LE
#define GET_UINT64_LE(n,b,i)                            \
{                                                       \
    (n) = ( (uint64_t) (b)[(i) + 7] << 56 )             \
        | ( (uint64_t) (b)[(i) + 6] << 48 )             \
        | ( (uint64_t) (b)[(i) + 5] << 40 )             \
        | ( (uint64_t) (b)[(i) + 4] << 32 )             \
        | ( (uint64_t) (b)[(i) + 3] << 24 )             \
        | ( (uint64_t) (b)[(i) + 2] << 16 )             \
        | ( (uint64_t) (b)[(i) + 1] <<  8 )             \
        | ( (uint64_t) (b)[(i)    ]       );            \
}
#endif

#ifndef PUT_UINT64_LE
#define PUT_UINT64_LE(n,b,i)                            \
{                                                       \
    (b)[(i) + 7] = (unsigned char) ( (n) >> 56 );       \
    (b)[(i) + 6] = (unsigned char) ( (n) >> 48 );       \
    (b)[(i) + 5] = (unsigned char) ( (n) >> 40 );       \
    (b)[(i) + 4] = (unsigned char) ( (n) >> 32 );       \
    (b)[(i) + 3] = (unsigned char) ( (n) >> 24 );       \
    (b)[(i) + 2] = (unsigned char) ( (n) >> 16 );       \
    (b)[(i) + 1] = (unsigned char) ( (n) >>  8 );       \
    (b)[(i)    ] = (unsigned char) ( (n)       );       \
}
#endif

/*
 * GF(2^128) multiplication function
 *
 * This function multiplies a field element by x in the polynomial field
 * representation. It uses 64-bit word operations to gain speed but compensates
 * for machine endianness and hence works correctly on both big and little
 * endian machines.
 */
static void mbedtls_gf128mul_x_ble( unsigned char r[16],
                                    const unsigned char x[16] )
{
    uint64_t a, b, ra, rb;

    GET_UINT64_LE( a, x, 0 );
    GET_UINT64_LE( b, x, 8 );

    ra = ( a << 1 )  ^ 0x0087 >> ( 8 - ( ( b >> 63 ) << 3 ) );
    rb = ( a >> 63 ) | ( b << 1 );

    PUT_UINT64_LE( ra, r, 0 );
    PUT_UINT64_LE( rb, r, 8 );
}

/*
 * AES-XTS buffer encryption/decryption
 */
int mbedtls_aes_crypt_xts( mbedtls_aes_xts_context *ctx,
                           int mode,
                           size_t length,
                           const unsigned char data_unit[16],
                           const unsigned char *input,
                           unsigned char *output )
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
    size_t blocks = length / 16;
    size_t leftover = length % 16;
    unsigned char tweak[16];
    unsigned char prev_tweak[16];
    unsigned char tmp[16];

    AES_VALIDATE_RET( ctx != NULL );
    AES_VALIDATE_RET( mode == MBEDTLS_AES_ENCRYPT ||
                      mode == MBEDTLS_AES_DECRYPT );
    AES_VALIDATE_RET( data_unit != NULL );
    AES_VALIDATE_RET( input != NULL );
    AES_VALIDATE_RET( output != NULL );

    /* Data units must be at least 16 bytes long. */
    if( length < 16 )
        return (MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH);

    /* NIST SP 800-38E disallows data units larger than 2**20 blocks. */
    if( length > ( 1 << 20 ) * 16 )
        return (MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH);

    /* Compute the tweak. */
    ret = mbedtls_aes_crypt_ecb( &ctx->tweak, MBEDTLS_AES_ENCRYPT,
                                 data_unit, tweak );
    if( ret != 0 )
        return( ret );

    while( blocks-- )
    {
        size_t i;

        if( leftover && ( mode == MBEDTLS_AES_DECRYPT ) && blocks == 0 )
        {
            /* We are on the last block in a decrypt operation that has
             * leftover bytes, so we need to use the next tweak for this block,
             * and this tweak for the lefover bytes. Save the current tweak for
             * the leftovers and then update the current tweak for use on this,
             * the last full block. */
            memcpy( prev_tweak, tweak, sizeof( tweak ) );
            mbedtls_gf128mul_x_ble( tweak, tweak );
        }

        for( i = 0; i < 16; i++ )
            tmp[i] = input[i] ^ tweak[i];

        ret = mbedtls_aes_crypt_ecb( &ctx->crypt, mode, tmp, tmp );
        if( ret != 0 )
            return( ret );

        for( i = 0; i < 16; i++ )
            output[i] = tmp[i] ^ tweak[i];

        /* Update the tweak for the next block. */
        mbedtls_gf128mul_x_ble( tweak, tweak );

        output += 16;
        input += 16;
    }

    if( leftover )
    {
        /* If we are on the leftover bytes in a decrypt operation, we need to
         * use the previous tweak for these bytes (as saved in prev_tweak). */
        unsigned char *t = mode == MBEDTLS_AES_DECRYPT ? prev_tweak : tweak;

        /* We are now on the final part of the data unit, which doesn't divide
         * evenly by 16. It's time for ciphertext stealing. */
        size_t i;
        unsigned char *prev_output = output - 16;

        /* Copy ciphertext bytes from the previous block to our output for each
         * byte of cyphertext we won't steal. At the same time, copy the
         * remainder of the input for this final round (since the loop bounds
         * are the same). */
        for( i = 0; i < leftover; i++ )
        {
            output[i] = prev_output[i];
            tmp[i] = input[i] ^ t[i];
        }

        /* Copy ciphertext bytes from the previous block for input in this
         * round. */
        for( ; i < 16; i++ )
            tmp[i] = prev_output[i] ^ t[i];

        ret = mbedtls_aes_crypt_ecb( &ctx->crypt, mode, tmp, tmp );
        if( ret != 0 )
            return (ret);

        /* Write the result back to the previous block, overriding the previous
         * output we copied. */
        for( i = 0; i < 16; i++ )
            prev_output[i] = tmp[i] ^ t[i];
    }

    return( 0 );
}
#endif /* MBEDTLS_CIPHER_MODE_XTS */

#if defined(MBEDTLS_CIPHER_MODE_CFB)
/*
 * AES-CFB128 buffer encryption/decryption
 */
int mbedtls_aes_crypt_cfb128(mbedtls_aes_context *ctx,
                             int mode,
                             size_t length,
                             size_t *iv_off,
                             unsigned char iv[16],
                             const unsigned char *input,
                             unsigned char *output)
{
    int ret;
    int c;
    size_t n;

    AES_VALIDATE_RET( ctx != NULL );
    AES_VALIDATE_RET( mode == MBEDTLS_AES_ENCRYPT ||
                      mode == MBEDTLS_AES_DECRYPT );
    AES_VALIDATE_RET( iv_off != NULL );
    AES_VALIDATE_RET( iv != NULL );
    AES_VALIDATE_RET( input != NULL );
    AES_VALIDATE_RET( output != NULL );

    n = *iv_off;

    if (mode == MBEDTLS_AES_DECRYPT) {
        while (length--) {
            if (n == 0) {
                ret = mbedtls_aes_crypt_ecb(ctx, MBEDTLS_AES_ENCRYPT, iv, iv);
                if (ret != 0)
                    return (ret);
            }

            c = *input++;
            *output++ = (unsigned char)(c ^ iv[n]);
            iv[n] = (unsigned char) c;

            n = (n + 1) & 0x0F;
        }
    } else {
        while (length--) {
            if (n == 0) {
                ret = mbedtls_aes_crypt_ecb(ctx, MBEDTLS_AES_ENCRYPT, iv, iv);
                if (ret != 0)
                    return (ret);
            }

            iv[n] = *output++ = (unsigned char)(iv[n] ^ *input++);

            n = (n + 1) & 0x0F;
        }
    }

    *iv_off = n;

    return (0);
}

/*
 * AES-CFB8 buffer encryption/decryption
 */
int mbedtls_aes_crypt_cfb8(mbedtls_aes_context *ctx,
                           int mode,
                           size_t length,
                           unsigned char iv[16],
                           const unsigned char *input,
                           unsigned char *output)
{
    int ret;
    unsigned char c;
    unsigned char ov[17];

    AES_VALIDATE_RET( ctx != NULL );
    AES_VALIDATE_RET( mode == MBEDTLS_AES_ENCRYPT ||
                      mode == MBEDTLS_AES_DECRYPT );
    AES_VALIDATE_RET( iv != NULL );
    AES_VALIDATE_RET( input != NULL );
    AES_VALIDATE_RET( output != NULL );

    while (length--) {
        memcpy(ov, iv, 16);
        ret = mbedtls_aes_crypt_ecb(ctx, MBEDTLS_AES_ENCRYPT, iv, iv);
        if (ret != 0)
            return (ret);

        if (mode == MBEDTLS_AES_DECRYPT) {
            ov[16] = *input;
        }

        c = *output++ = (unsigned char)(iv[0] ^ *input++);

        if (mode == MBEDTLS_AES_ENCRYPT) {
            ov[16] = c;
        }

        memcpy(iv, ov + 1, 16);
    }

    return (0);
}

#endif /*MBEDTLS_CIPHER_MODE_CFB */

#if defined(MBEDTLS_CIPHER_MODE_OFB)
/*
 * AES-OFB (Output Feedback Mode) buffer encryption/decryption
 */
int mbedtls_aes_crypt_ofb( mbedtls_aes_context *ctx,
                           size_t length,
                           size_t *iv_off,
                           unsigned char iv[16],
                           const unsigned char *input,
                           unsigned char *output )
{
    int ret = 0;
    size_t n;

    AES_VALIDATE_RET( ctx != NULL );
    AES_VALIDATE_RET( iv_off != NULL );
    AES_VALIDATE_RET( iv != NULL );
    AES_VALIDATE_RET( input != NULL );
    AES_VALIDATE_RET( output != NULL );

    n = *iv_off;

    if( n > 15 )
        return( MBEDTLS_ERR_AES_BAD_INPUT_DATA );

    while( length-- )
    {
        if( n == 0 )
        {
            ret = mbedtls_aes_crypt_ecb( ctx, MBEDTLS_AES_ENCRYPT, iv, iv );
            if( ret != 0 )
                goto exit;
        }
        *output++ =  *input++ ^ iv[n];

        n = ( n + 1 ) & 0x0F;
    }

    *iv_off = n;

exit:
    return( ret );
}
#endif /* MBEDTLS_CIPHER_MODE_OFB */

#if defined(MBEDTLS_CIPHER_MODE_CTR)
/*
 * AES-CTR buffer encryption/decryption
 */
int mbedtls_aes_crypt_ctr(mbedtls_aes_context *ctx,
                          size_t length,
                          size_t *nc_off,
                          unsigned char nonce_counter[16],
                          unsigned char stream_block[16],
                          const unsigned char *input,
                          unsigned char *output)
{
    int c, i;
    size_t n;

    AES_VALIDATE_RET( ctx != NULL );
    AES_VALIDATE_RET( nc_off != NULL );
    AES_VALIDATE_RET( nonce_counter != NULL );
    AES_VALIDATE_RET( stream_block != NULL );
    AES_VALIDATE_RET( input != NULL );
    AES_VALIDATE_RET( output != NULL );

    n = *nc_off;

    while (length--) {
        if (n == 0) {
            if (mbedtls_aes_crypt_ecb(ctx, MBEDTLS_AES_ENCRYPT, nonce_counter, stream_block) != 0) {
                return (MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED);
            }

            for (i = 16; i > 0; i--)
                if (++nonce_counter[i - 1] != 0) {
                    break;
                }
        }
        c = *input++;
        *output++ = (unsigned char)(c ^ stream_block[n]);

        n = (n + 1) & 0x0F;
    }

    *nc_off = n;

    return (0);
}
#endif /* MBEDTLS_CIPHER_MODE_CTR */

int mbedtls_internal_aes_encrypt(mbedtls_aes_context *ctx,
                                 const unsigned char input[16],
                                 unsigned char output[16])
{

    if (HAL_CRYP_Encrypt(&ctx->hcryp_aes, (uint32_t *)input, 16, (uint32_t *)output, ST_AES_TIMEOUT) != HAL_OK) {
        return (MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED);
    }
    return (0);

}

int mbedtls_internal_aes_decrypt(mbedtls_aes_context *ctx,
                                 const unsigned char input[16],
                                 unsigned char output[16])
{
    if (HAL_CRYP_Decrypt(&ctx->hcryp_aes, (uint32_t *)input, 16, (uint32_t *)output, ST_AES_TIMEOUT) != HAL_OK) {
        return MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED;
    }
    return (0);
}
#endif /* MBEDTLS_AES_ALT */
#endif /* MBEDTLS_AES_C */