text: /*
   * Copyright 1995-2020 The OpenSSL Project Authors. All Rights Reserved.
   *
   * Licensed under the Apache License 2.0 (the "License").  You may not use
   * this file except in compliance with the License.  You can obtain a copy
   * in the file LICENSE in the source distribution or at
   * https://www.openssl.org/source/license.html
   */
  
  #include <openssl/opensslconf.h>
  
  #include <stdio.h>
  #include <string.h>
  #include <sys/types.h>
  #include <sys/stat.h>
  #include "apps.h"
  #include "progs.h"
  #include <openssl/bio.h>
  #include <openssl/err.h>
  #include <openssl/bn.h>
  #include <openssl/rsa.h>
  #include <openssl/evp.h>
  #include <openssl/x509.h>
  #include <openssl/pem.h>
  #include <openssl/rand.h>
  
  #define DEFBITS 2048
  #define DEFPRIMES 2
  
  static int verbose = 0;
  
  static int genrsa_cb(EVP_PKEY_CTX *ctx);
  
  typedef enum OPTION_choice {
      OPT_ERR = -1, OPT_EOF = 0, OPT_HELP,
      OPT_3, OPT_F4, OPT_ENGINE,
      OPT_OUT, OPT_PASSOUT, OPT_CIPHER, OPT_PRIMES, OPT_VERBOSE,
      OPT_R_ENUM, OPT_PROV_ENUM
  } OPTION_CHOICE;
  
  const OPTIONS genrsa_options[] = {
      {OPT_HELP_STR, 1, '-', "Usage: %s [options] numbits\n"},
  
      OPT_SECTION("General"),
      {"help", OPT_HELP, '-', "Display this summary"},
  #ifndef OPENSSL_NO_ENGINE
      {"engine", OPT_ENGINE, 's', "Use engine, possibly a hardware device"},
  #endif
  
      OPT_SECTION("Input"),
      {"3", OPT_3, '-', "Use 3 for the E value"},
      {"F4", OPT_F4, '-', "Use F4 (0x10001) for the E value"},
      {"f4", OPT_F4, '-', "Use F4 (0x10001) for the E value"},
  
      OPT_SECTION("Output"),
      {"out", OPT_OUT, '>', "Output the key to specified file"},
      {"passout", OPT_PASSOUT, 's', "Output file pass phrase source"},
      {"primes", OPT_PRIMES, 'p', "Specify number of primes"},
      {"verbose", OPT_VERBOSE, '-', "Verbose output"},
      {"", OPT_CIPHER, '-', "Encrypt the output with any supported cipher"},
  
      OPT_R_OPTIONS,
      OPT_PROV_OPTIONS,
  
      OPT_PARAMETERS(),
      {"numbits", 0, 0, "Size of key in bits"},
      {NULL}
  };
  
  int genrsa_main(int argc, char **argv)
  {
      BN_GENCB *cb = BN_GENCB_new();
      ENGINE *eng = NULL;
      BIGNUM *bn = BN_new();
      RSA *rsa;
      BIO *out = NULL;
      const BIGNUM *e;
      EVP_PKEY *pkey = NULL;
      EVP_PKEY_CTX *ctx = NULL;
      const EVP_CIPHER *enc = NULL;
      int ret = 1, num = DEFBITS, private = 0, primes = DEFPRIMES;
      unsigned long f4 = RSA_F4;
      char *outfile = NULL, *passoutarg = NULL, *passout = NULL;
      char *prog, *hexe, *dece;
      OPTION_CHOICE o;
      unsigned char *ebuf = NULL;
  
      if (bn == NULL || cb == NULL)
          goto end;
  
      prog = opt_init(argc, argv, genrsa_options);
      while ((o = opt_next()) != OPT_EOF) {
          switch (o) {
          case OPT_EOF:
          case OPT_ERR:
  opthelp:
              BIO_printf(bio_err, "%s: Use -help for summary.\n", prog);
              goto end;
          case OPT_HELP:
              ret = 0;
              opt_help(genrsa_options);
              goto end;
          case OPT_3:
              f4 = RSA_3;
              break;
          case OPT_F4:
              f4 = RSA_F4;
              break;
          case OPT_OUT:
              outfile = opt_arg();
              break;
          case OPT_ENGINE:
              eng = setup_engine(opt_arg(), 0);
              break;
          case OPT_R_CASES:
              if (!opt_rand(o))
                  goto end;
              break;
          case OPT_PROV_CASES:
              if (!opt_provider(o))
                  goto end;
              break;
          case OPT_PASSOUT:
              passoutarg = opt_arg();
              break;
          case OPT_CIPHER:
              if (!opt_cipher(opt_unknown(), &enc))
                  goto end;
              break;
          case OPT_PRIMES:
              if (!opt_int(opt_arg(), &primes))
                  goto end;
              break;
          case OPT_VERBOSE:
              verbose = 1;
              break;
          }
      }
      argc = opt_num_rest();
      argv = opt_rest();
  
      if (argc == 1) {
          if (!opt_int(argv[0], &num) || num <= 0)
              goto end;
          if (num > OPENSSL_RSA_MAX_MODULUS_BITS)
              BIO_printf(bio_err,
                         "Warning: It is not recommended to use more than %d bit for RSA keys.\n"
                         "         Your key size is %d! Larger key size may behave not as expected.\n",
                         OPENSSL_RSA_MAX_MODULUS_BITS, num);
      } else if (argc > 0) {
          BIO_printf(bio_err, "Extra arguments given.\n");
          goto opthelp;
      }
  
      private = 1;
      if (!app_passwd(NULL, passoutarg, NULL, &passout)) {
          BIO_printf(bio_err, "Error getting password\n");
          goto end;
      }
  
      out = bio_open_owner(outfile, FORMAT_PEM, private);
      if (out == NULL)
          goto end;
  
      if (!init_gen_str(&ctx, "RSA", eng, 0))
          goto end;
  
      EVP_PKEY_CTX_set_cb(ctx, genrsa_cb);
      EVP_PKEY_CTX_set_app_data(ctx, bio_err);
  
      if (EVP_PKEY_CTX_set_rsa_keygen_bits(ctx, num) <= 0) {
          BIO_printf(bio_err, "Error setting RSA length\n");
          goto end;
      }
      if (!BN_set_word(bn, f4)) {
          BIO_printf(bio_err, "Error allocating RSA public exponent\n");
          goto end;
      }
      if (EVP_PKEY_CTX_set_rsa_keygen_pubexp(ctx, bn) <= 0) {
          BIO_printf(bio_err, "Error setting RSA public exponent\n");
          goto end;
      }
      if (EVP_PKEY_CTX_set_rsa_keygen_primes(ctx, primes) <= 0) {
          BIO_printf(bio_err, "Error setting number of primes\n");
          goto end;
      }
      if (verbose)
          BIO_printf(bio_err, "Generating RSA private key, %d bit long modulus (%d primes)\n",
                     num, primes);
      if (!EVP_PKEY_keygen(ctx, &pkey)) {
          BIO_printf(bio_err, "Error generating RSA key\n");
          goto end;
      }
  
      if (verbose) {
          if ((rsa = EVP_PKEY_get0_RSA(pkey)) != NULL) {
              RSA_get0_key(rsa, NULL, &e, NULL);
          } else {
              BIO_printf(bio_err, "Error cannot access RSA e\n");
              goto end;
          }
          hexe = BN_bn2hex(e);
          dece = BN_bn2dec(e);
          if (hexe && dece) {
              BIO_printf(bio_err, "e is %s (0x%s)\n", dece, hexe);
          }
          OPENSSL_free(hexe);
          OPENSSL_free(dece);
      }
      if (!PEM_write_bio_PrivateKey(out, pkey, enc, NULL, 0, NULL, passout))
          goto end;
  
      ret = 0;
   end:
      BN_free(bn);
      BN_GENCB_free(cb);
      EVP_PKEY_CTX_free(ctx);
      EVP_PKEY_free(pkey);
      BIO_free_all(out);
      release_engine(eng);
      OPENSSL_free(passout);
      OPENSSL_free(ebuf);
      if (ret != 0)
          ERR_print_errors(bio_err);
      return ret;
  }
  
  static int genrsa_cb(EVP_PKEY_CTX *ctx)
  {
      char c = '*';
      BIO *b = EVP_PKEY_CTX_get_app_data(ctx);
      int p = EVP_PKEY_CTX_get_keygen_info(ctx, 0);
  
      if (!verbose)
          return 1;
  
      if (p == 0)
          c = '.';
      if (p == 1)
          c = '+';
      if (p == 2)
          c = '*';
      if (p == 3)
          c = '\n';
      BIO_write(b, &c, 1);
      (void)BIO_flush(b);
      return 1;
  }
  