text: /*
   *  Public key-based signature creation program
   *
   *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
   *  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.
   *
   *  This file is part of mbed TLS (https://tls.mbed.org)
   */
  
  #if !defined(MBEDTLS_CONFIG_FILE)
  #include "mbedtls/config.h"
  #else
  #include MBEDTLS_CONFIG_FILE
  #endif
  
  #if defined(MBEDTLS_PLATFORM_C)
  #include "mbedtls/platform.h"
  #else
  #include <stdio.h>
  #include <stdlib.h>
  #define mbedtls_snprintf        snprintf
  #define mbedtls_printf          printf
  #define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
  #define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
  #endif /* MBEDTLS_PLATFORM_C */
  
  #if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_ENTROPY_C) ||  \
      !defined(MBEDTLS_SHA256_C) || !defined(MBEDTLS_MD_C) || \
      !defined(MBEDTLS_PK_PARSE_C) || !defined(MBEDTLS_FS_IO) ||    \
      !defined(MBEDTLS_CTR_DRBG_C)
  int main( void )
  {
      mbedtls_printf("MBEDTLS_BIGNUM_C and/or MBEDTLS_ENTROPY_C and/or "
             "MBEDTLS_SHA256_C and/or MBEDTLS_MD_C and/or "
             "MBEDTLS_PK_PARSE_C and/or MBEDTLS_FS_IO and/or "
             "MBEDTLS_CTR_DRBG_C not defined.\n");
      return( 0 );
  }
  #else
  
  #include "mbedtls/error.h"
  #include "mbedtls/entropy.h"
  #include "mbedtls/ctr_drbg.h"
  #include "mbedtls/md.h"
  #include "mbedtls/pk.h"
  
  #include <stdio.h>
  #include <string.h>
  
  /*
   * For the currently used signature algorithms the buffer to store any signature
   * must be at least of size MAX(MBEDTLS_ECDSA_MAX_LEN, MBEDTLS_MPI_MAX_SIZE)
   */
  #if MBEDTLS_ECDSA_MAX_LEN > MBEDTLS_MPI_MAX_SIZE
  #define SIGNATURE_MAX_SIZE MBEDTLS_ECDSA_MAX_LEN
  #else
  #define SIGNATURE_MAX_SIZE MBEDTLS_MPI_MAX_SIZE
  #endif
  
  int main( int argc, char *argv[] )
  {
      FILE *f;
      int ret = 1;
      int exit_code = MBEDTLS_EXIT_FAILURE;
      mbedtls_pk_context pk;
      mbedtls_entropy_context entropy;
      mbedtls_ctr_drbg_context ctr_drbg;
      unsigned char hash[32];
      unsigned char buf[SIGNATURE_MAX_SIZE];
      char filename[512];
      const char *pers = "mbedtls_pk_sign";
      size_t olen = 0;
  
      mbedtls_entropy_init( &entropy );
      mbedtls_ctr_drbg_init( &ctr_drbg );
      mbedtls_pk_init( &pk );
  
      if( argc != 3 )
      {
          mbedtls_printf( "usage: mbedtls_pk_sign <key_file> <filename>\n" );
  
  #if defined(_WIN32)
          mbedtls_printf( "\n" );
  #endif
  
          goto exit;
      }
  
      mbedtls_printf( "\n  . Seeding the random number generator..." );
      fflush( stdout );
  
      if( ( ret = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func, &entropy,
                                 (const unsigned char *) pers,
                                 strlen( pers ) ) ) != 0 )
      {
          mbedtls_printf( " failed\n  ! mbedtls_ctr_drbg_seed returned -0x%04x\n", -ret );
          goto exit;
      }
  
      mbedtls_printf( "\n  . Reading private key from '%s'", argv[1] );
      fflush( stdout );
  
      if( ( ret = mbedtls_pk_parse_keyfile( &pk, argv[1], "" ) ) != 0 )
      {
          mbedtls_printf( " failed\n  ! Could not parse '%s'\n", argv[1] );
          goto exit;
      }
  
      /*
       * Compute the SHA-256 hash of the input file,
       * then calculate the signature of the hash.
       */
      mbedtls_printf( "\n  . Generating the SHA-256 signature" );
      fflush( stdout );
  
      if( ( ret = mbedtls_md_file(
                      mbedtls_md_info_from_type( MBEDTLS_MD_SHA256 ),
                      argv[2], hash ) ) != 0 )
      {
          mbedtls_printf( " failed\n  ! Could not open or read %s\n\n", argv[2] );
          goto exit;
      }
  
      if( ( ret = mbedtls_pk_sign( &pk, MBEDTLS_MD_SHA256, hash, 0, buf, &olen,
                           mbedtls_ctr_drbg_random, &ctr_drbg ) ) != 0 )
      {
          mbedtls_printf( " failed\n  ! mbedtls_pk_sign returned -0x%04x\n", -ret );
          goto exit;
      }
  
      /*
       * Write the signature into <filename>.sig
       */
      mbedtls_snprintf( filename, sizeof(filename), "%s.sig", argv[2] );
  
      if( ( f = fopen( filename, "wb+" ) ) == NULL )
      {
          mbedtls_printf( " failed\n  ! Could not create %s\n\n", filename );
          goto exit;
      }
  
      if( fwrite( buf, 1, olen, f ) != olen )
      {
          mbedtls_printf( "failed\n  ! fwrite failed\n\n" );
          fclose( f );
          goto exit;
      }
  
      fclose( f );
  
      mbedtls_printf( "\n  . Done (created \"%s\")\n\n", filename );
  
      exit_code = MBEDTLS_EXIT_SUCCESS;
  
  exit:
      mbedtls_pk_free( &pk );
      mbedtls_ctr_drbg_free( &ctr_drbg );
      mbedtls_entropy_free( &entropy );
  
  #if defined(MBEDTLS_ERROR_C)
      if( exit_code != MBEDTLS_EXIT_SUCCESS )
      {
          mbedtls_strerror( ret, (char *) buf, sizeof(buf) );
          mbedtls_printf( "  !  Last error was: %s\n", buf );
      }
  #endif
  
  #if defined(_WIN32)
      mbedtls_printf( "  + Press Enter to exit this program.\n" );
      fflush( stdout ); getchar();
  #endif
  
      return( exit_code );
  }
  #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_ENTROPY_C &&
            MBEDTLS_SHA256_C && MBEDTLS_PK_PARSE_C && MBEDTLS_FS_IO &&
            MBEDTLS_CTR_DRBG_C */
  