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STM32L486RG/mbedtls: add aes hw acceleration #3962

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Original file line number Diff line number Diff line change
@@ -0,0 +1,30 @@
/*
* mbedtls_device.h
*******************************************************************************
* Copyright (c) 2017, STMicroelectronics
* 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.
*
*/
#ifndef MBEDTLS_DEVICE_H
#define MBEDTLS_DEVICE_H

#define MBEDTLS_AES_ALT

//the following defines are provided to maintain compatibility between STM32 families
#define __HAL_RCC_CRYP_CLK_ENABLE __HAL_RCC_AES_CLK_ENABLE
#define __HAL_RCC_CRYP_FORCE_RESET __HAL_RCC_AES_FORCE_RESET
#define __HAL_RCC_CRYP_RELEASE_RESET __HAL_RCC_AES_RELEASE_RESET
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Aren't these implementation specific definitions?
Shouldn't these be in some STM common header file, or in the aes_alt.c file?
mbedtls_device.h should be included only from mbedtls files(specifically platform_mbed.h), so I think these definitions will not be used anywhere

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You're right, I'll move them

#define CRYP AES
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Where is this definition called form?

#endif /* MBEDTLS_DEVICE_H */
62 changes: 51 additions & 11 deletions features/mbedtls/targets/TARGET_STM/aes_alt.c
Original file line number Diff line number Diff line change
Expand Up @@ -28,17 +28,22 @@ static int aes_set_key( mbedtls_aes_context *ctx, const unsigned char *key, unsi
switch( keybits )
{
case 128:
ctx->hcryp_aes.Init.KeySize = CRYP_KEYSIZE_128B;
memcpy(ctx->aes_key, key, 16);
break;
ctx->hcryp_aes.Init.KeySize = CRYP_KEYSIZE_128B;
memcpy(ctx->aes_key, key, 16);
break;
case 192:
ctx->hcryp_aes.Init.KeySize = CRYP_KEYSIZE_192B;
memcpy(ctx->aes_key, key, 24);
break;
#if defined (TARGET_STM32L486xG)
return(MBEDTLS_ERR_AES_INVALID_KEY_LENGTH);
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The alternative implementation should support the full API. If HW doesn't support, then the SW implementation should be used

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I don't like to increase the SW size for this feature, but I understand the need.
I'll have to rework the pull request to use SW in case of 192bits key size. @0xc0170 I guess you can add 'do not merge' label at the moment.

#else
ctx->hcryp_aes.Init.KeySize = CRYP_KEYSIZE_192B;
memcpy(ctx->aes_key, key, 24);
break;
#endif

case 256:
ctx->hcryp_aes.Init.KeySize = CRYP_KEYSIZE_256B;
memcpy(ctx->aes_key, key, 32);
break;
ctx->hcryp_aes.Init.KeySize = CRYP_KEYSIZE_256B;
memcpy(ctx->aes_key, key, 32);
break;
default : return( MBEDTLS_ERR_AES_INVALID_KEY_LENGTH );
}

Expand All @@ -52,6 +57,9 @@ static int aes_set_key( mbedtls_aes_context *ctx, const unsigned char *key, unsi
__HAL_RCC_CRYP_CLK_ENABLE();

ctx->hcryp_aes.Init.pKey = ctx->aes_key;
#if defined (TARGET_STM32L486xG)
ctx->hcryp_aes.Init.KeyWriteFlag = CRYP_KEY_WRITE_ENABLE;
#endif
if (HAL_CRYP_Init(&ctx->hcryp_aes) == HAL_ERROR)
return (HAL_ERROR);

Expand Down Expand Up @@ -148,14 +156,46 @@ int mbedtls_aes_crypt_cbc( mbedtls_aes_context *ctx,
if( mode == MBEDTLS_AES_DECRYPT )
{
ctx->hcryp_aes.Init.pInitVect = &iv[0]; // used in process, not in the init

#if defined (TARGET_STM32L486xG)
if ((ctx->hcryp_aes.Init.OperatingMode != CRYP_ALGOMODE_KEYDERIVATION_DECRYPT) || \
(ctx->hcryp_aes.Init.ChainingMode != CRYP_CHAINMODE_AES_CBC) || \
(ctx->hcryp_aes.Init.KeyWriteFlag != CRYP_KEY_WRITE_ENABLE)) {
/* Re-initialize AES IP with proper parameters */
if (HAL_CRYP_DeInit(&ctx->hcryp_aes) != HAL_OK)
return HAL_ERROR;
ctx->hcryp_aes.Init.OperatingMode = CRYP_ALGOMODE_KEYDERIVATION_DECRYPT;
ctx->hcryp_aes.Init.ChainingMode = CRYP_CHAINMODE_AES_CBC;
ctx->hcryp_aes.Init.KeyWriteFlag = CRYP_KEY_WRITE_ENABLE;
if (HAL_CRYP_Init(&ctx->hcryp_aes) != HAL_OK)
return HAL_ERROR;
}

status = HAL_CRYPEx_AES(&ctx->hcryp_aes, (uint8_t *)input, length, (uint8_t *)output, 10);
#else
status = HAL_CRYP_AESCBC_Decrypt(&ctx->hcryp_aes, (uint8_t *)input, length, (uint8_t *)output, 10);
#endif
}
else
{
ctx->hcryp_aes.Init.pInitVect = &iv[0]; // used in process, not in the init

#if defined (TARGET_STM32L486xG)
if ((ctx->hcryp_aes.Init.OperatingMode != CRYP_ALGOMODE_ENCRYPT) || \
(ctx->hcryp_aes.Init.ChainingMode != CRYP_CHAINMODE_AES_CBC) || \
(ctx->hcryp_aes.Init.KeyWriteFlag != CRYP_KEY_WRITE_ENABLE)) {
/* Re-initialize AES IP with proper parameters */
if (HAL_CRYP_DeInit(&ctx->hcryp_aes) != HAL_OK)
return HAL_ERROR;
ctx->hcryp_aes.Init.OperatingMode = CRYP_ALGOMODE_ENCRYPT;
ctx->hcryp_aes.Init.ChainingMode = CRYP_CHAINMODE_AES_CBC;
ctx->hcryp_aes.Init.KeyWriteFlag = CRYP_KEY_WRITE_ENABLE;
if (HAL_CRYP_Init(&ctx->hcryp_aes) != HAL_OK)
return HAL_ERROR;
}

status = HAL_CRYPEx_AES(&ctx->hcryp_aes, (uint8_t *)input, length, (uint8_t *)output, 10);
#else
status = HAL_CRYP_AESCBC_Encrypt(&ctx->hcryp_aes, (uint8_t *)input, length, (uint8_t *)output, 10);
#endif
}
return( status );
}
Expand Down
2 changes: 1 addition & 1 deletion targets/targets.json
Original file line number Diff line number Diff line change
Expand Up @@ -1087,7 +1087,7 @@
"supported_toolchains": ["ARM", "uARM", "IAR", "GCC_ARM"],
"inherits": ["Target"],
"detect_code": ["0827"],
"macros": ["TRANSACTION_QUEUE_SIZE_SPI=2","USBHOST_OTHER"],
"macros": ["TRANSACTION_QUEUE_SIZE_SPI=2","USBHOST_OTHER", "MBEDTLS_CONFIG_HW_SUPPORT"],
"device_has": ["ANALOGIN", "ANALOGOUT", "CAN", "I2C", "I2CSLAVE", "I2C_ASYNCH", "INTERRUPTIN", "LOWPOWERTIMER", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "RTC", "SERIAL", "SERIAL_ASYNCH", "SERIAL_FC", "SLEEP", "SPI", "SPISLAVE", "SPI_ASYNCH", "STDIO_MESSAGES", "TRNG"],
"release_versions": ["2", "5"],
"device_name": "STM32L486RG"
Expand Down