/*
 *  ESP32 hardware accelerated SHA1/256/512 implementation
 *  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 SHA-1 standard was published by NIST in 1993.
 *
 *  http://www.itl.nist.gov/fipspubs/fip180-1.htm
 */

#include <string.h>
#include <sys/lock.h>
#include "hwcrypto/sha.h"
#include "rom/ets_sys.h"


static _lock_t sha_lock;

void esp_sha_acquire_hardware( void )
{
    /* newlib locks lazy initialize on ESP-IDF */
    _lock_acquire(&sha_lock);
    ets_sha_enable();
}

void esp_sha_release_hardware( void )
{
    /* Want to empty internal SHA buffers where possible,
       need to check if this is sufficient for this. */
    SHA_CTX zero = { 0 };
    ets_sha_init(&zero);
    ets_sha_disable();
    _lock_release(&sha_lock);
}

void esp_sha1_init( esp_sha_context *ctx )
{
    bzero( ctx, sizeof( esp_sha_context ) );
}

void esp_sha1_free( esp_sha_context *ctx )
{
    if ( ctx == NULL ) {
        return;
    }

    bzero( ctx, sizeof( esp_sha_context ) );
}

void esp_sha1_clone( esp_sha_context *dst, const esp_sha_context *src )
{
    *dst = *src;
}

/*
 * SHA-1 context setup
 */
void esp_sha1_start( esp_sha_context *ctx )
{
    esp_sha_acquire_hardware();
    ctx->context_type = SHA1;
}

/*
 * SHA-1 process buffer
 */
void esp_sha1_update( esp_sha_context *ctx, const unsigned char *input, size_t ilen )
{
    ets_sha_update(&ctx->context, ctx->context_type, input, ilen * 8);
}

/*
 * SHA-1 final digest
 */
void esp_sha1_finish( esp_sha_context *ctx, unsigned char output[20] )
{
    ets_sha_finish(&ctx->context, ctx->context_type, output);
    esp_sha_release_hardware();
}

/* Full SHA-1 calculation */
void esp_sha1( const unsigned char *input, size_t ilen, unsigned char output[20] )
{
    esp_sha_context ctx;

    esp_sha1_init( &ctx );
    esp_sha1_start( &ctx );
    esp_sha1_update( &ctx, input, ilen );
    esp_sha1_finish( &ctx, output );
    esp_sha1_free( &ctx );
}

void esp_sha256_init( esp_sha_context *ctx )
{
    bzero( ctx, sizeof( esp_sha_context ) );
}

void esp_sha256_free( esp_sha_context *ctx )
{
    if ( ctx == NULL ) {
        return;
    }

    bzero( ctx, sizeof( esp_sha_context ) );
}

void esp_sha256_clone( esp_sha_context *dst, const esp_sha_context *src )
{
    *dst = *src;
}

/*
 * SHA-256 context setup
 */
void esp_sha256_start( esp_sha_context *ctx, int is224 )
{
    esp_sha_acquire_hardware();
    ets_sha_init(&ctx->context);

    if ( is224 == 0 ) {
        /* SHA-256 */
        ctx->context_type = SHA2_256;
    } else {
        /* SHA-224 is not supported! */
        ctx->context_type = SHA_INVALID;
    }
}

/*
 * SHA-256 process buffer
 */
void esp_sha256_update( esp_sha_context *ctx, const unsigned char *input, size_t ilen )
{
    ets_sha_update(&ctx->context, ctx->context_type, input, ilen * 8);
}

/*
 * SHA-256 final digest
 */
void esp_sha256_finish( esp_sha_context *ctx, unsigned char output[32] )
{
    if ( ctx->context_type == SHA2_256 ) {
        ets_sha_finish(&ctx->context, ctx->context_type, output);
    } else {
        /* No hardware SHA-224 support, but mbedTLS API doesn't allow failure.
           For now, zero the output to make it clear it's not valid. */
        bzero( output, 28 );
    }
    esp_sha_release_hardware();
}

/*
 * Full SHA-256 calculation
 */
void esp_sha256( const unsigned char *input, size_t ilen, unsigned char output[32], int is224 )
{
    esp_sha_context ctx;

    esp_sha256_init( &ctx );
    esp_sha256_start( &ctx, is224 );
    esp_sha256_update( &ctx, input, ilen );
    esp_sha256_finish( &ctx, output );
    esp_sha256_free( &ctx );
}


/////
void esp_sha512_init( esp_sha_context *ctx )
{
    memset( ctx, 0, sizeof( esp_sha_context ) );
}

void esp_sha512_free( esp_sha_context *ctx )
{
    if ( ctx == NULL ) {
        return;
    }

    bzero( ctx, sizeof( esp_sha_context ) );
}

void esp_sha512_clone( esp_sha_context *dst, const esp_sha_context *src )
{
    *dst = *src;
}

/*
 * SHA-512 context setup
 */
void esp_sha512_start( esp_sha_context *ctx, int is384 )
{
    esp_sha_acquire_hardware();
    ets_sha_init(&ctx->context);

    if ( is384 == 0 ) {
        /* SHA-512 */
        ctx->context_type = SHA2_512;
    } else {
        /* SHA-384 */
        ctx->context_type = SHA2_384;
    }
}

/*
 * SHA-512 process buffer
 */
void esp_sha512_update( esp_sha_context *ctx, const unsigned char *input, size_t ilen )
{
    ets_sha_update(&ctx->context, ctx->context_type, input, ilen * 8);
}

/*
 * SHA-512 final digest
 */
void esp_sha512_finish( esp_sha_context *ctx, unsigned char output[64] )
{
    ets_sha_finish(&ctx->context, ctx->context_type, output);
    esp_sha_release_hardware();
}

/*
 * Full SHA-512 calculation
 */
void esp_sha512( const unsigned char *input, size_t ilen, unsigned char output[64], int is384 )
{
    esp_sha_context ctx;

    esp_sha512_init( &ctx );
    esp_sha512_start( &ctx, is384 );
    esp_sha512_update( &ctx, input, ilen );
    esp_sha512_finish( &ctx, output );
    esp_sha512_free( &ctx );
}

////