esp-idf/components/mbedtls/port/esp32s2beta/aes.c
Marius Vikhammer c63684cf6c hw crypto: activated hardware acceleration for esp32s2beta
Activated AES, RSA and SHA hardware acceleration for esp32s2 and enabled related unit tests.

Updated with changes made for ESP32 from 0a04034, 961f59f and caea288.

Added performance targets for esp32s2beta

Closes IDF-757
2019-12-12 12:37:29 +08:00

742 lines
20 KiB
C

/**
* \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) 2016-2017, 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 "esp32s2beta/aes.h"
#include "soc/dport_reg.h"
#include "soc/hwcrypto_reg.h"
#include <sys/lock.h>
#include <freertos/FreeRTOS.h>
#include "soc/cpu.h"
#include <stdio.h>
#define AES_BLOCK_BYTES 16
/* AES uses a spinlock mux not a lock as the underlying block operation
only takes a small number of cycles, much less than using
a mutex for this.
For CBC, CFB, etc. this may mean that interrupts are disabled for a longer
period of time for bigger data lengths.
*/
static portMUX_TYPE aes_spinlock = portMUX_INITIALIZER_UNLOCKED;
static inline bool valid_key_length(const esp_aes_context *ctx)
{
return ctx->key_bytes == 128/8 || ctx->key_bytes == 192/8 || ctx->key_bytes == 256/8;
}
void esp_aes_acquire_hardware( void )
{
/* newlib locks lazy initialize on ESP-IDF */
portENTER_CRITICAL(&aes_spinlock);
/* Enable AES hardware */
REG_SET_BIT(DPORT_PERI_CLK_EN_REG, DPORT_PERI_EN_AES);
/* Clear reset on digital signature unit,
otherwise AES unit is held in reset also. */
REG_CLR_BIT(DPORT_PERI_RST_EN_REG,
DPORT_PERI_EN_AES
| DPORT_PERI_EN_DIGITAL_SIGNATURE);
}
void esp_aes_release_hardware( void )
{
/* Disable AES hardware */
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. */
REG_CLR_BIT(DPORT_PERI_CLK_EN_REG, DPORT_PERI_EN_AES);
portEXIT_CRITICAL(&aes_spinlock);
}
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 ) );
}
/*
* AES key schedule (same for encryption or decryption, as hardware handles schedule)
*
*/
int esp_aes_setkey( esp_aes_context *ctx, const unsigned char *key,
unsigned int keybits )
{
if (keybits != 128 && keybits != 192 && keybits != 256) {
return MBEDTLS_ERR_AES_INVALID_KEY_LENGTH;
}
ctx->key_bytes = keybits / 8;
memcpy(ctx->key, key, ctx->key_bytes);
ctx->key_in_hardware = 0;
return 0;
}
/*
* Helper function to copy key from esp_aes_context buffer
* to hardware key registers.
*
* Call only while holding esp_aes_acquire_hardware().
*/
static inline void esp_aes_setkey_hardware( esp_aes_context *ctx, int mode)
{
const uint32_t MODE_DECRYPT_BIT = 4;
unsigned mode_reg_base = (mode == ESP_AES_ENCRYPT) ? 0 : MODE_DECRYPT_BIT;
ctx->key_in_hardware = 0;
for (int i = 0; i < ctx->key_bytes/4; ++i) {
REG_WRITE(AES_KEY_BASE + i * 4, *(((uint32_t *)ctx->key) + i));
ctx->key_in_hardware += 4;
}
REG_WRITE(AES_MODE_REG, mode_reg_base + ((ctx->key_bytes / 8) - 2));
/* Fault injection check: all words of key data should have been written to hardware */
if (ctx->key_in_hardware < 16
|| ctx->key_in_hardware != ctx->key_bytes) {
abort();
}
}
/* Run a single 16 byte block of AES, using the hardware engine.
*
* Call only while holding esp_aes_acquire_hardware().
*/
static inline int esp_aes_block(esp_aes_context *ctx, const void *input, void *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) {
bzero(output, 16);
return MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH;
}
memcpy((void *)AES_TEXT_IN_BASE, input, AES_BLOCK_BYTES);
REG_WRITE(AES_TRIGGER_REG, 1);
while (REG_READ(AES_STATE_REG) != 0) { }
memcpy(output, (void *)AES_TEXT_OUT_BASE, AES_BLOCK_BYTES);
return 0;
}
/*
* AES-ECB block encryption
*/
int esp_internal_aes_encrypt( esp_aes_context *ctx,
const unsigned char input[16],
unsigned char output[16] )
{
int r;
if (!valid_key_length(ctx)) {
return MBEDTLS_ERR_AES_INVALID_KEY_LENGTH;
}
esp_aes_acquire_hardware();
esp_aes_setkey_hardware(ctx, ESP_AES_ENCRYPT);
r = esp_aes_block(ctx, input, output);
esp_aes_release_hardware();
return r;
}
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 decryption
*/
int esp_internal_aes_decrypt( esp_aes_context *ctx,
const unsigned char input[16],
unsigned char output[16] )
{
int r;
if (!valid_key_length(ctx)) {
return MBEDTLS_ERR_AES_INVALID_KEY_LENGTH;
}
esp_aes_acquire_hardware();
esp_aes_setkey_hardware(ctx, ESP_AES_DECRYPT);
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 encryption/decryption
*/
int esp_aes_crypt_ecb( esp_aes_context *ctx,
int mode,
const unsigned char input[16],
unsigned char output[16] )
{
int r;
if (!valid_key_length(ctx)) {
return MBEDTLS_ERR_AES_INVALID_KEY_LENGTH;
}
esp_aes_acquire_hardware();
ctx->key_in_hardware = 0;
esp_aes_setkey_hardware(ctx, 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 i;
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;
esp_aes_setkey_hardware(ctx, mode);
if ( mode == ESP_AES_DECRYPT ) {
while ( length > 0 ) {
memcpy(temp, input_words, 16);
esp_aes_block(ctx, input_words, output_words);
for ( i = 0; i < 4; i++ ) {
output_words[i] = output_words[i] ^ iv_words[i];
}
memcpy( iv_words, temp, 16 );
input_words += 4;
output_words += 4;
length -= 16;
}
} else { // ESP_AES_ENCRYPT
while ( length > 0 ) {
for ( i = 0; i < 4; i++ ) {
output_words[i] = input_words[i] ^ iv_words[i];
}
esp_aes_block(ctx, output_words, output_words);
memcpy( iv_words, output_words, 16 );
input_words += 4;
output_words += 4;
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;
if (!valid_key_length(ctx)) {
return MBEDTLS_ERR_AES_INVALID_KEY_LENGTH;
}
esp_aes_acquire_hardware();
ctx->key_in_hardware = 0;
esp_aes_setkey_hardware(ctx, ESP_AES_ENCRYPT);
if ( mode == ESP_AES_DECRYPT ) {
while ( length-- ) {
if ( n == 0 ) {
esp_aes_block(ctx, 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 ) {
esp_aes_block(ctx, 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];
if (!valid_key_length(ctx)) {
return MBEDTLS_ERR_AES_INVALID_KEY_LENGTH;
}
esp_aes_acquire_hardware();
ctx->key_in_hardware = 0;
esp_aes_setkey_hardware(ctx, ESP_AES_ENCRYPT);
while ( length-- ) {
memcpy( ov, iv, 16 );
esp_aes_block(ctx, 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;
if (!valid_key_length(ctx)) {
return MBEDTLS_ERR_AES_INVALID_KEY_LENGTH;
}
esp_aes_acquire_hardware();
ctx->key_in_hardware = 0;
esp_aes_setkey_hardware(ctx, ESP_AES_ENCRYPT);
while ( length-- ) {
if ( n == 0 ) {
esp_aes_block(ctx, 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;
}
/*
* 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 = 0;
size_t n;
if ( ctx == NULL || iv_off == NULL || iv == NULL ||
input == NULL || output == NULL ) {
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;
esp_aes_setkey_hardware(ctx, ESP_AES_ENCRYPT);
while( length-- ) {
if( n == 0 ) {
esp_aes_block(ctx, iv, iv);
}
*output++ = *input++ ^ iv[n];
n = ( n + 1 ) & 0x0F;
}
*iv_off = n;
esp_aes_release_hardware();
return( ret );
}
/* Below XTS implementation is copied aes.c of mbedtls library.
* When MBEDTLS_AES_ALT is defined mbedtls expects alternate
* definition of XTS functions to be available. Even if this
* could have been avoided, it is done for consistency reason.
*/
void esp_aes_xts_init( esp_aes_xts_context *ctx )
{
esp_aes_init( &ctx->crypt );
esp_aes_init( &ctx->tweak );
}
void esp_aes_xts_free( esp_aes_xts_context *ctx )
{
esp_aes_free( &ctx->crypt );
esp_aes_free( &ctx->tweak );
}
static int esp_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 esp_aes_xts_setkey_enc( esp_aes_xts_context *ctx,
const unsigned char *key,
unsigned int keybits)
{
int ret;
const unsigned char *key1, *key2;
unsigned int key1bits, key2bits;
ret = esp_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 = esp_aes_setkey( &ctx->tweak, key2, key2bits );
if( ret != 0 )
return( ret );
/* Set crypt key for encryption. */
return esp_aes_setkey( &ctx->crypt, key1, key1bits );
}
int esp_aes_xts_setkey_dec( esp_aes_xts_context *ctx,
const unsigned char *key,
unsigned int keybits)
{
int ret;
const unsigned char *key1, *key2;
unsigned int key1bits, key2bits;
ret = esp_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 = esp_aes_setkey( &ctx->tweak, key2, key2bits );
if( ret != 0 )
return( ret );
/* Set crypt key for decryption. */
return esp_aes_setkey( &ctx->crypt, key1, key1bits );
}
/* Endianess 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
typedef unsigned char esp_be128[16];
/*
* 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 endianess and hence works correctly on both big and little
* endian machines.
*/
static void esp_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 esp_aes_crypt_xts( esp_aes_xts_context *ctx,
int mode,
size_t length,
const unsigned char data_unit[16],
const unsigned char *input,
unsigned char *output )
{
int ret;
size_t blocks = length / 16;
size_t leftover = length % 16;
unsigned char tweak[16];
unsigned char prev_tweak[16];
unsigned char tmp[16];
/* Sectors must be at least 16 bytes. */
if( length < 16 )
return MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH;
/* NIST SP 80-38E disallows data units larger than 2**20 blocks. */
if( length > ( 1 << 20 ) * 16 )
return MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH;
/* Compute the tweak. */
ret = esp_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 ) );
esp_gf128mul_x_ble( tweak, tweak );
}
for( i = 0; i < 16; i++ )
tmp[i] = input[i] ^ tweak[i];
ret = esp_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. */
esp_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 = esp_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 );
}