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/**
* \brief AES block cipher, ESP block hardware accelerated version
* Based on mbedTLS FIPS-197 compliant version.
*
* Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
* Additions Copyright (C) 2016-2017, Espressif Systems (Shanghai) PTE Ltd
* 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.
*
*/
/*
* 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
*/
#include <string.h>
#include "mbedtls/aes.h"
#include "mbedtls/platform_util.h"
#include "esp_log.h"
#include "aes/esp_aes.h"
#include "soc/hwcrypto_periph.h"
#include <sys/lock.h>
#include "hal/aes_hal.h"
#include "hal/aes_ll.h"
#include "esp_aes_internal.h"
#include "sdkconfig.h"
#include <freertos/FreeRTOS.h>
#include <stdio.h>
#include "esp_private/esp_crypto_lock_internal.h"
static const char *TAG = "esp-aes";
/* AES uses a spinlock mux not a lock as the underlying block operation
only takes 208 cycles (to write key & compute block), +600 cycles
for DPORT protection but +3400 cycles again if you use a full sized lock.
For CBC, CFB, etc. this may mean that interrupts are disabled for a longer
period of time for bigger lengths. However at the moment this has to happen
anyway due to DPORT protection...
*/
static portMUX_TYPE aes_spinlock = portMUX_INITIALIZER_UNLOCKED;
void esp_aes_acquire_hardware( void )
{
portENTER_CRITICAL(&aes_spinlock);
/* Enable AES hardware */
AES_RCC_ATOMIC() {
aes_ll_enable_bus_clock(true);
aes_ll_reset_register();
}
}
void esp_aes_release_hardware( void )
{
/* Disable AES hardware */
AES_RCC_ATOMIC() {
aes_ll_enable_bus_clock(false);
}
portEXIT_CRITICAL(&aes_spinlock);
}
/* Run a single 16 byte block of AES, using the hardware engine.
*
* Call only while holding esp_aes_acquire_hardware().
*
* The function esp_aes_block zeroises the output buffer in the case of following conditions:
* 1. If key is not written in the hardware
* 2. If the fault injection check failed
*/
static int esp_aes_block(esp_aes_context *ctx, const void *input, void *output)
{
uint32_t i0, i1, i2, i3;
const uint32_t *input_words = (uint32_t *)input;
uint32_t *output_words = (uint32_t *)output;
/* If no key is written to hardware yet, either the user hasn't called
mbedtls_aes_setkey_enc/mbedtls_aes_setkey_dec - meaning we also don't
know which mode to use - or a fault skipped the
key write to hardware. Treat this as a fatal error and zero the output block.
*/
if (ctx->key_in_hardware != ctx->key_bytes) {
mbedtls_platform_zeroize(output, 16);
return MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH;
}
i0 = input_words[0];
i1 = input_words[1];
i2 = input_words[2];
i3 = input_words[3];
#ifdef CONFIG_MBEDTLS_AES_USE_PSEUDO_ROUND_FUNC
esp_aes_enable_pseudo_rounds(CONFIG_MBEDTLS_AES_USE_PSEUDO_ROUND_FUNC_STRENGTH);
#endif /* CONFIG_MBEDTLS_AES_USE_PSEUDO_ROUND_FUNC */
aes_hal_transform_block(input, output);
/* Physical security check: Verify the AES accelerator actually ran, and wasn't
skipped due to external fault injection while starting the peripheral.
Note that i0,i1,i2,i3 are copied from input buffer in case input==output.
Bypassing this check requires at least one additional fault.
*/
if (i0 == output_words[0] && i1 == output_words[1] && i2 == output_words[2] && i3 == output_words[3]) {
// calling zeroing functions to narrow the
// window for a double-fault of the abort step, here
memset(output, 0, 16);
mbedtls_platform_zeroize(output, 16);
abort();
}
return 0;
}
static int esp_aes_validate_input(esp_aes_context *ctx, const unsigned char *input,
const unsigned char *output )
{
if (!ctx) {
ESP_LOGD(TAG, "No AES context supplied");
return -1;
}
if (!input) {
ESP_LOGD(TAG, "No input supplied");
return -1;
}
if (!output) {
ESP_LOGD(TAG, "No output supplied");
return -1;
}
return 0;
}
void esp_aes_encrypt(esp_aes_context *ctx,
const unsigned char input[16],
unsigned char output[16] )
{
esp_internal_aes_encrypt(ctx, input, output);
}
/*
* AES-ECB block encryption
*/
int esp_internal_aes_encrypt(esp_aes_context *ctx,
const unsigned char input[16],
unsigned char output[16] )
{
int r = -1;
if (esp_aes_validate_input(ctx, input, output)) {
return MBEDTLS_ERR_AES_BAD_INPUT_DATA;
}
if (!valid_key_length(ctx)) {
return MBEDTLS_ERR_AES_INVALID_KEY_LENGTH;
}
esp_aes_acquire_hardware();
ctx->key_in_hardware = 0;
ctx->key_in_hardware = aes_hal_setkey(ctx->key, ctx->key_bytes, ESP_AES_ENCRYPT);
r = esp_aes_block(ctx, input, output);
esp_aes_release_hardware();
return r;
}
void esp_aes_decrypt(esp_aes_context *ctx,
const unsigned char input[16],
unsigned char output[16] )
{
esp_internal_aes_decrypt(ctx, input, output);
}
/*
* AES-ECB block decryption
*/
int esp_internal_aes_decrypt(esp_aes_context *ctx,
const unsigned char input[16],
unsigned char output[16] )
{
int r = -1;
if (esp_aes_validate_input(ctx, input, output)) {
return MBEDTLS_ERR_AES_BAD_INPUT_DATA;
}
if (!valid_key_length(ctx)) {
return MBEDTLS_ERR_AES_INVALID_KEY_LENGTH;
}
esp_aes_acquire_hardware();
ctx->key_in_hardware = 0;
ctx->key_in_hardware = aes_hal_setkey(ctx->key, ctx->key_bytes, ESP_AES_DECRYPT);
r = esp_aes_block(ctx, input, output);
esp_aes_release_hardware();
return r;
}
/*
* AES-ECB block encryption/decryption
*/
int esp_aes_crypt_ecb(esp_aes_context *ctx,
int mode,
const unsigned char input[16],
unsigned char output[16] )
{
int r = -1;
if (esp_aes_validate_input(ctx, input, output)) {
return MBEDTLS_ERR_AES_BAD_INPUT_DATA;
}
if (!valid_key_length(ctx)) {
return MBEDTLS_ERR_AES_INVALID_KEY_LENGTH;
}
esp_aes_acquire_hardware();
ctx->key_in_hardware = 0;
ctx->key_in_hardware = aes_hal_setkey(ctx->key, ctx->key_bytes, mode);
r = esp_aes_block(ctx, input, output);
esp_aes_release_hardware();
return r;
}
/*
* AES-CBC buffer encryption/decryption
*/
int esp_aes_crypt_cbc(esp_aes_context *ctx,
int mode,
size_t length,
unsigned char iv[16],
const unsigned char *input,
unsigned char *output )
{
int ret = -1;
if (esp_aes_validate_input(ctx, input, output)) {
return MBEDTLS_ERR_AES_BAD_INPUT_DATA;
}
if (!iv) {
ESP_LOGD(TAG, "No IV supplied");
return MBEDTLS_ERR_AES_BAD_INPUT_DATA;
}
uint32_t *output_words = (uint32_t *)output;
const uint32_t *input_words = (const uint32_t *)input;
uint32_t *iv_words = (uint32_t *)iv;
unsigned char temp[16];
if ( length % 16 ) {
return ( ERR_ESP_AES_INVALID_INPUT_LENGTH );
}
if (!valid_key_length(ctx)) {
return MBEDTLS_ERR_AES_INVALID_KEY_LENGTH;
}
esp_aes_acquire_hardware();
ctx->key_in_hardware = 0;
ctx->key_in_hardware = aes_hal_setkey(ctx->key, ctx->key_bytes, mode);
if ( mode == ESP_AES_DECRYPT ) {
while ( length > 0 ) {
memcpy(temp, input_words, 16);
ret = esp_aes_block(ctx, input_words, output_words);
if (ret != 0) {
goto cleanup;
}
output_words[0] = output_words[0] ^ iv_words[0];
output_words[1] = output_words[1] ^ iv_words[1];
output_words[2] = output_words[2] ^ iv_words[2];
output_words[3] = output_words[3] ^ iv_words[3];
memcpy( iv_words, temp, 16 );
input_words += 4;
output_words += 4;
length -= 16;
}
} else { // ESP_AES_ENCRYPT
while ( length > 0 ) {
output_words[0] = input_words[0] ^ iv_words[0];
output_words[1] = input_words[1] ^ iv_words[1];
output_words[2] = input_words[2] ^ iv_words[2];
output_words[3] = input_words[3] ^ iv_words[3];
ret = esp_aes_block(ctx, output_words, output_words);
if (ret != 0) {
goto cleanup;
}
memcpy( iv_words, output_words, 16 );
input_words += 4;
output_words += 4;
length -= 16;
}
}
ret = 0;
cleanup:
esp_aes_release_hardware();
return ret;
}
/*
* AES-CFB128 buffer encryption/decryption
*/
int esp_aes_crypt_cfb128(esp_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 = -1;
if (esp_aes_validate_input(ctx, input, output)) {
return MBEDTLS_ERR_AES_BAD_INPUT_DATA;
}
if (!iv) {
ESP_LOGE(TAG, "No IV supplied");
return MBEDTLS_ERR_AES_BAD_INPUT_DATA;
}
if (!iv_off) {
ESP_LOGE(TAG, "No IV offset supplied");
return MBEDTLS_ERR_AES_BAD_INPUT_DATA;
}
if (!valid_key_length(ctx)) {
return MBEDTLS_ERR_AES_INVALID_KEY_LENGTH;
}
int c;
size_t n = *iv_off;
esp_aes_acquire_hardware();
ctx->key_in_hardware = 0;
ctx->key_in_hardware = aes_hal_setkey(ctx->key, ctx->key_bytes, ESP_AES_ENCRYPT);
if ( mode == ESP_AES_DECRYPT ) {
while ( length-- ) {
if ( n == 0 ) {
ret = esp_aes_block(ctx, iv, iv);
if (ret != 0) {
goto cleanup;
}
}
c = *input++;
*output++ = (unsigned char)( c ^ iv[n] );
iv[n] = (unsigned char) c;
n = ( n + 1 ) & 0x0F;
}
} else {
while ( length-- ) {
if ( n == 0 ) {
ret = esp_aes_block(ctx, iv, iv);
if (ret != 0) {
goto cleanup;
}
}
iv[n] = *output++ = (unsigned char)( iv[n] ^ *input++ );
n = ( n + 1 ) & 0x0F;
}
}
*iv_off = n;
ret = 0;
cleanup:
esp_aes_release_hardware();
return ret;
}
/*
* AES-CFB8 buffer encryption/decryption
*/
int esp_aes_crypt_cfb8(esp_aes_context *ctx,
int mode,
size_t length,
unsigned char iv[16],
const unsigned char *input,
unsigned char *output )
{
int ret = -1;
unsigned char c;
unsigned char ov[17];
if (esp_aes_validate_input(ctx, input, output)) {
return MBEDTLS_ERR_AES_BAD_INPUT_DATA;
}
if (!iv) {
ESP_LOGE(TAG, "No IV supplied");
return MBEDTLS_ERR_AES_BAD_INPUT_DATA;
}
if (!valid_key_length(ctx)) {
return MBEDTLS_ERR_AES_INVALID_KEY_LENGTH;
}
esp_aes_acquire_hardware();
ctx->key_in_hardware = 0;
ctx->key_in_hardware = aes_hal_setkey(ctx->key, ctx->key_bytes, ESP_AES_ENCRYPT);
while ( length-- ) {
memcpy( ov, iv, 16 );
ret = esp_aes_block(ctx, iv, iv);
if (ret != 0) {
goto cleanup;
}
if ( mode == ESP_AES_DECRYPT ) {
ov[16] = *input;
}
c = *output++ = (unsigned char)( iv[0] ^ *input++ );
if ( mode == ESP_AES_ENCRYPT ) {
ov[16] = c;
}
memcpy( iv, ov + 1, 16 );
}
ret = 0;
cleanup:
esp_aes_release_hardware();
return ret;
}
/*
* AES-CTR buffer encryption/decryption
*/
int esp_aes_crypt_ctr(esp_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, ret = -1;
if (esp_aes_validate_input(ctx, input, output)) {
return MBEDTLS_ERR_AES_BAD_INPUT_DATA;
}
if (!stream_block) {
ESP_LOGE(TAG, "No stream supplied");
return MBEDTLS_ERR_AES_BAD_INPUT_DATA;
}
if (!nonce_counter) {
ESP_LOGE(TAG, "No nonce supplied");
return MBEDTLS_ERR_AES_BAD_INPUT_DATA;
}
if (!nc_off) {
ESP_LOGE(TAG, "No nonce offset supplied");
return MBEDTLS_ERR_AES_BAD_INPUT_DATA;
}
size_t n = *nc_off;
if (!valid_key_length(ctx)) {
return MBEDTLS_ERR_AES_INVALID_KEY_LENGTH;
}
esp_aes_acquire_hardware();
ctx->key_in_hardware = 0;
ctx->key_in_hardware = aes_hal_setkey(ctx->key, ctx->key_bytes, ESP_AES_ENCRYPT);
while ( length-- ) {
if ( n == 0 ) {
ret = esp_aes_block(ctx, nonce_counter, stream_block);
if (ret != 0) {
goto cleanup;
}
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;
ret = 0;
cleanup:
esp_aes_release_hardware();
return ret;
}
/*
* AES-OFB (Output Feedback Mode) buffer encryption/decryption
*/
int esp_aes_crypt_ofb(esp_aes_context *ctx,
size_t length,
size_t *iv_off,
unsigned char iv[16],
const unsigned char *input,
unsigned char *output )
{
int ret = -1;
size_t n;
if (esp_aes_validate_input(ctx, input, output)) {
return MBEDTLS_ERR_AES_BAD_INPUT_DATA;
}
if (!iv) {
ESP_LOGE(TAG, "No IV supplied");
return MBEDTLS_ERR_AES_BAD_INPUT_DATA;
}
if (!iv_off) {
ESP_LOGE(TAG, "No IV offset supplied");
return MBEDTLS_ERR_AES_BAD_INPUT_DATA;
}
n = *iv_off;
if (n > 15) {
return (MBEDTLS_ERR_AES_BAD_INPUT_DATA);
}
if (!valid_key_length(ctx)) {
return MBEDTLS_ERR_AES_INVALID_KEY_LENGTH;
}
esp_aes_acquire_hardware();
ctx->key_in_hardware = 0;
ctx->key_in_hardware = aes_hal_setkey(ctx->key, ctx->key_bytes, ESP_AES_ENCRYPT);
while (length--) {
if ( n == 0 ) {
ret = esp_aes_block(ctx, iv, iv);
if (ret != 0) {
goto cleanup;
}
}
*output++ = *input++ ^ iv[n];
n = ( n + 1 ) & 0x0F;
}
*iv_off = n;
ret = 0;
cleanup:
esp_aes_release_hardware();
return ( ret );
}
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