esp-idf/components/esp32/hwcrypto/aes.c

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/**
* \brief AES block cipher, ESP32 hardware accelerated version
* Based on mbedTLS FIPS-197 compliant version.
*
* Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
* Additions Copyright (C) 2016, 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 "hwcrypto/aes.h"
#include "rom/aes.h"
#include "soc/dport_reg.h"
#include <sys/lock.h>
static _lock_t aes_lock;
void esp_aes_acquire_hardware( void )
{
/* newlib locks lazy initialize on ESP-IDF */
_lock_acquire(&aes_lock);
/* Enable AES hardware */
DPORT_REG_SET_BIT(DPORT_PERI_CLK_EN_REG, DPORT_PERI_EN_AES);
/* Clear reset on digital signature & secure boot units,
otherwise AES unit is held in reset also. */
DPORT_REG_CLR_BIT(DPORT_PERI_RST_EN_REG,
DPORT_PERI_EN_AES
| DPORT_PERI_EN_DIGITAL_SIGNATURE
| DPORT_PERI_EN_SECUREBOOT);
}
void esp_aes_release_hardware( void )
{
/* Disable AES hardware */
DPORT_REG_SET_BIT(DPORT_PERI_RST_EN_REG, DPORT_PERI_EN_AES);
/* Don't return other units to reset, as this pulls
reset on RSA & SHA units, respectively. */
DPORT_REG_CLR_BIT(DPORT_PERI_CLK_EN_REG, DPORT_PERI_EN_AES);
_lock_release(&aes_lock);
}
void esp_aes_init( esp_aes_context *ctx )
{
bzero( ctx, sizeof( esp_aes_context ) );
}
void esp_aes_free( esp_aes_context *ctx )
{
if ( ctx == NULL ) {
return;
}
bzero( ctx, sizeof( esp_aes_context ) );
}
/* Translate number of bits to an AES_BITS enum */
static int keybits_to_aesbits(unsigned int keybits)
{
switch (keybits) {
case 128:
return AES128;
case 192:
return AES192;
break;
case 256:
return AES256;
default:
return ( ERR_ESP_AES_INVALID_KEY_LENGTH );
}
}
/*
* AES key schedule (encryption)
*
*/
int esp_aes_setkey_enc( esp_aes_context *ctx, const unsigned char *key,
unsigned int keybits )
{
uint16_t keybytes = keybits / 8;
int aesbits = keybits_to_aesbits(keybits);
if (aesbits < 0) {
return aesbits;
}
ctx->enc.aesbits = aesbits;
bzero(ctx->enc.key, sizeof(ctx->enc.key));
memcpy(ctx->enc.key, key, keybytes);
return 0;
}
/*
* AES key schedule (decryption)
*
*/
int esp_aes_setkey_dec( esp_aes_context *ctx, const unsigned char *key,
unsigned int keybits )
{
uint16_t keybytes = keybits / 8;
int aesbits = keybits_to_aesbits(keybits);
if (aesbits < 0) {
return aesbits;
}
ctx->dec.aesbits = aesbits;
bzero(ctx->dec.key, sizeof(ctx->dec.key));
memcpy(ctx->dec.key, key, keybytes);
return 0;
}
/*
* Helper function to copy key from esp_aes_context buffer
* to hardware key registers.
*
* Only call when protected by esp_aes_acquire_hardware().
*/
static inline int esp_aes_setkey_hardware( esp_aes_context *ctx, int mode)
{
if ( mode == ESP_AES_ENCRYPT ) {
ets_aes_setkey_enc(ctx->enc.key, ctx->enc.aesbits);
} else {
ets_aes_setkey_dec(ctx->dec.key, ctx->dec.aesbits);
}
return 0;
}
/*
* AES-ECB block encryption
*/
void esp_aes_encrypt( esp_aes_context *ctx,
const unsigned char input[16],
unsigned char output[16] )
{
esp_aes_acquire_hardware();
esp_aes_setkey_hardware(ctx, ESP_AES_ENCRYPT);
ets_aes_crypt(input, output);
esp_aes_release_hardware();
}
/*
* AES-ECB block decryption
*/
void esp_aes_decrypt( esp_aes_context *ctx,
const unsigned char input[16],
unsigned char output[16] )
{
esp_aes_acquire_hardware();
esp_aes_setkey_hardware(ctx, ESP_AES_DECRYPT);
ets_aes_crypt(input, output);
esp_aes_release_hardware();
}
/*
* 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] )
{
esp_aes_acquire_hardware();
esp_aes_setkey_hardware(ctx, mode);
ets_aes_crypt(input, output);
esp_aes_release_hardware();
return 0;
}
/*
* 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 i;
unsigned char temp[16];
if ( length % 16 ) {
return ( ERR_ESP_AES_INVALID_INPUT_LENGTH );
}
esp_aes_acquire_hardware();
esp_aes_setkey_hardware(ctx, mode);
if ( mode == ESP_AES_DECRYPT ) {
while ( length > 0 ) {
memcpy( temp, input, 16 );
ets_aes_crypt(input, output);
for ( i = 0; i < 16; i++ ) {
output[i] = (unsigned char)( output[i] ^ iv[i] );
}
memcpy( iv, temp, 16 );
input += 16;
output += 16;
length -= 16;
}
} else {
while ( length > 0 ) {
for ( i = 0; i < 16; i++ ) {
output[i] = (unsigned char)( input[i] ^ iv[i] );
}
ets_aes_crypt(output, output);
memcpy( iv, output, 16 );
input += 16;
output += 16;
length -= 16;
}
}
esp_aes_release_hardware();
return 0;
}
/*
* 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 c;
size_t n = *iv_off;
esp_aes_acquire_hardware();
esp_aes_setkey_hardware(ctx, ESP_AES_ENCRYPT);
if ( mode == ESP_AES_DECRYPT ) {
while ( length-- ) {
if ( n == 0 ) {
ets_aes_crypt(iv, iv );
}
c = *input++;
*output++ = (unsigned char)( c ^ iv[n] );
iv[n] = (unsigned char) c;
n = ( n + 1 ) & 0x0F;
}
} else {
while ( length-- ) {
if ( n == 0 ) {
ets_aes_crypt(iv, iv );
}
iv[n] = *output++ = (unsigned char)( iv[n] ^ *input++ );
n = ( n + 1 ) & 0x0F;
}
}
*iv_off = n;
esp_aes_release_hardware();
return 0;
}
/*
* 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 )
{
unsigned char c;
unsigned char ov[17];
esp_aes_acquire_hardware();
esp_aes_setkey_hardware(ctx, ESP_AES_ENCRYPT);
while ( length-- ) {
memcpy( ov, iv, 16 );
ets_aes_crypt(iv, iv);
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 );
}
esp_aes_release_hardware();
return 0;
}
/*
* 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;
size_t n = *nc_off;
esp_aes_acquire_hardware();
esp_aes_setkey_hardware(ctx, ESP_AES_ENCRYPT);
while ( length-- ) {
if ( n == 0 ) {
ets_aes_crypt(nonce_counter, stream_block);
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;
esp_aes_release_hardware();
return 0;
}