text: /*
   * SHA-256 implementation with hardware ESP support added.
   *
   * SPDX-FileCopyrightText: The Mbed TLS Contributors
   *
   * SPDX-License-Identifier: Apache-2.0
   *
   * SPDX-FileContributor: 2016-2022 Espressif Systems (Shanghai) CO LTD
   */
  /*
   *  The SHA-256 Secure Hash Standard was published by NIST in 2002.
   *
   *  http://csrc.nist.gov/publications/fips/fips180-2/fips180-2.pdf
   */
  
  #include <mbedtls/build_info.h>
  
  #if defined(MBEDTLS_SHA256_C) && defined(MBEDTLS_SHA256_ALT)
  
  #include "mbedtls/sha256.h"
  
  #include <string.h>
  
  #if defined(MBEDTLS_SELF_TEST)
  #if defined(MBEDTLS_PLATFORM_C)
  #include "mbedtls/platform.h"
  #else
  #include <stdio.h>
  #define mbedtls_printf printf
  #endif /* MBEDTLS_PLATFORM_C */
  #endif /* MBEDTLS_SELF_TEST */
  
  #include "sha/sha_dma.h"
  
  /* Implementation that should never be optimized out by the compiler */
  static void mbedtls_zeroize( void *v, size_t n )
  {
      volatile unsigned char *p = v;
      while ( n-- ) {
          *p++ = 0;
      }
  }
  
  /*
   * 32-bit integer manipulation macros (big endian)
   */
  #ifndef GET_UINT32_BE
  #define GET_UINT32_BE(n,b,i)                            \
  do {                                                    \
      (n) = ( (uint32_t) (b)[(i)    ] << 24 )             \
          | ( (uint32_t) (b)[(i) + 1] << 16 )             \
          | ( (uint32_t) (b)[(i) + 2] <<  8 )             \
          | ( (uint32_t) (b)[(i) + 3]       );            \
  } while( 0 )
  #endif
  
  #ifndef PUT_UINT32_BE
  #define PUT_UINT32_BE(n,b,i)                            \
  do {                                                    \
      (b)[(i)    ] = (unsigned char) ( (n) >> 24 );       \
      (b)[(i) + 1] = (unsigned char) ( (n) >> 16 );       \
      (b)[(i) + 2] = (unsigned char) ( (n) >>  8 );       \
      (b)[(i) + 3] = (unsigned char) ( (n)       );       \
  } while( 0 )
  #endif
  
  void mbedtls_sha256_init( mbedtls_sha256_context *ctx )
  {
      memset( ctx, 0, sizeof( mbedtls_sha256_context ) );
  }
  
  void mbedtls_sha256_free( mbedtls_sha256_context *ctx )
  {
      if ( ctx == NULL ) {
          return;
      }
  
      mbedtls_zeroize( ctx, sizeof( mbedtls_sha256_context ) );
  }
  
  void mbedtls_sha256_clone( mbedtls_sha256_context *dst,
                             const mbedtls_sha256_context *src )
  {
      *dst = *src;
  }
  
  /*
   * SHA-256 context setup
   */
  int mbedtls_sha256_starts( mbedtls_sha256_context *ctx, int is224 )
  {
      memset( ctx, 0, sizeof( mbedtls_sha256_context ) );
  
      if ( is224 ) {
          ctx->mode = SHA2_224;
      } else {
          ctx->mode = SHA2_256;
      }
  
      return 0;
  }
  
  int mbedtls_internal_sha256_process( mbedtls_sha256_context *ctx, const unsigned char data[64] )
  {
      int ret;
      esp_sha_acquire_hardware();
      ret = esp_sha_dma(ctx->mode, data, 64, 0, 0, ctx->first_block);
      esp_sha_release_hardware();
  
      return ret;
  }
  
  /*
   * SHA-256 process buffer
   */
  int mbedtls_sha256_update( mbedtls_sha256_context *ctx, const unsigned char *input,
                                 size_t ilen )
  {
      int ret = 0;
      size_t fill;
      uint32_t left, len, local_len = 0;
  
      if ( ilen == 0 ) {
          return 0;
      }
  
      left = ctx->total[0] & 0x3F;
      fill = 64 - left;
  
      ctx->total[0] += (uint32_t) ilen;
      ctx->total[0] &= 0xFFFFFFFF;
  
      if ( ctx->total[0] < (uint32_t) ilen ) {
          ctx->total[1]++;
      }
  
      /* Check if any data pending from previous call to this API */
      if ( left && ilen >= fill ) {
          memcpy( (void *) (ctx->buffer + left), input, fill );
  
          input += fill;
          ilen  -= fill;
          left = 0;
          local_len = 64;
      }
  
      len = (ilen / 64) * 64;
  
      if ( len || local_len) {
          esp_sha_acquire_hardware();
  
          if (ctx->sha_state == ESP_SHA256_STATE_INIT) {
              ctx->first_block = true;
              ctx->sha_state = ESP_SHA256_STATE_IN_PROCESS;
          } else if (ctx->sha_state == ESP_SHA256_STATE_IN_PROCESS) {
              ctx->first_block = false;
              esp_sha_write_digest_state(ctx->mode, ctx->state);
          }
  
          ret = esp_sha_dma(ctx->mode, input, len,  ctx->buffer, local_len, ctx->first_block);
  
          esp_sha_read_digest_state(ctx->mode, ctx->state);
  
          esp_sha_release_hardware();
  
          if (ret != 0) {
              return ret;
          }
      }
  
      if ( ilen > 0 ) {
          memcpy( (void *) (ctx->buffer + left), input + len, ilen - len );
      }
  
      return 0;
  }
  
  static const unsigned char sha256_padding[64] = {
      0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
  };
  
  /*
   * SHA-256 final digest
   */
  int mbedtls_sha256_finish( mbedtls_sha256_context *ctx, unsigned char output[32] )
  {
      int ret;
      uint32_t last, padn;
      uint32_t high, low;
      unsigned char msglen[8];
  
      high = ( ctx->total[0] >> 29 )
             | ( ctx->total[1] <<  3 );
      low  = ( ctx->total[0] <<  3 );
  
      PUT_UINT32_BE( high, msglen, 0 );
      PUT_UINT32_BE( low,  msglen, 4 );
  
      last = ctx->total[0] & 0x3F;
      padn = ( last < 56 ) ? ( 56 - last ) : ( 120 - last );
  
      if ( ( ret = mbedtls_sha256_update( ctx, sha256_padding, padn ) ) != 0 ) {
          return ret;
      }
  
      if ( ( ret = mbedtls_sha256_update( ctx, msglen, 8 ) ) != 0 ) {
          return ret;
      }
  
      memcpy(output, ctx->state, 32);
  
      return ret;
  }
  
  #endif /* MBEDTLS_SHA256_C && MBEDTLS_SHA256_ALT */
  