text: /*
   * Copyright 1995-2017 The OpenSSL Project Authors. All Rights Reserved.
   *
   * Licensed under the OpenSSL license (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 <stdio.h>
  #include <string.h>
  #include <time.h>
  #include <openssl/err.h>
  #include <openssl/bn.h>
  #include "rsa_locl.h"
  
  /* X9.31 RSA key derivation and generation */
  
  int RSA_X931_derive_ex(RSA *rsa, BIGNUM *p1, BIGNUM *p2, BIGNUM *q1,
                         BIGNUM *q2, const BIGNUM *Xp1, const BIGNUM *Xp2,
                         const BIGNUM *Xp, const BIGNUM *Xq1, const BIGNUM *Xq2,
                         const BIGNUM *Xq, const BIGNUM *e, BN_GENCB *cb)
  {
      BIGNUM *r0 = NULL, *r1 = NULL, *r2 = NULL, *r3 = NULL;
      BN_CTX *ctx = NULL, *ctx2 = NULL;
      int ret = 0;
  
      if (!rsa)
          goto err;
  
      ctx = BN_CTX_new();
      if (ctx == NULL)
          goto err;
      BN_CTX_start(ctx);
  
      r0 = BN_CTX_get(ctx);
      r1 = BN_CTX_get(ctx);
      r2 = BN_CTX_get(ctx);
      r3 = BN_CTX_get(ctx);
  
      if (r3 == NULL)
          goto err;
      if (!rsa->e) {
          rsa->e = BN_dup(e);
          if (!rsa->e)
              goto err;
      } else {
          e = rsa->e;
      }
  
      /*
       * If not all parameters present only calculate what we can. This allows
       * test programs to output selective parameters.
       */
  
      if (Xp && rsa->p == NULL) {
          rsa->p = BN_new();
          if (rsa->p == NULL)
              goto err;
  
          if (!BN_X931_derive_prime_ex(rsa->p, p1, p2,
                                       Xp, Xp1, Xp2, e, ctx, cb))
              goto err;
      }
  
      if (Xq && rsa->q == NULL) {
          rsa->q = BN_new();
          if (rsa->q == NULL)
              goto err;
          if (!BN_X931_derive_prime_ex(rsa->q, q1, q2,
                                       Xq, Xq1, Xq2, e, ctx, cb))
              goto err;
      }
  
      if (rsa->p == NULL || rsa->q == NULL) {
          BN_CTX_end(ctx);
          BN_CTX_free(ctx);
          return 2;
      }
  
      /*
       * Since both primes are set we can now calculate all remaining
       * components.
       */
  
      /* calculate n */
      rsa->n = BN_new();
      if (rsa->n == NULL)
          goto err;
      if (!BN_mul(rsa->n, rsa->p, rsa->q, ctx))
          goto err;
  
      /* calculate d */
      if (!BN_sub(r1, rsa->p, BN_value_one()))
          goto err;               /* p-1 */
      if (!BN_sub(r2, rsa->q, BN_value_one()))
          goto err;               /* q-1 */
      if (!BN_mul(r0, r1, r2, ctx))
          goto err;               /* (p-1)(q-1) */
  
      if (!BN_gcd(r3, r1, r2, ctx))
          goto err;
  
      if (!BN_div(r0, NULL, r0, r3, ctx))
          goto err;               /* LCM((p-1)(q-1)) */
  
      ctx2 = BN_CTX_new();
      if (ctx2 == NULL)
          goto err;
  
      rsa->d = BN_mod_inverse(NULL, rsa->e, r0, ctx2); /* d */
      if (rsa->d == NULL)
          goto err;
  
      /* calculate d mod (p-1) */
      rsa->dmp1 = BN_new();
      if (rsa->dmp1 == NULL)
          goto err;
      if (!BN_mod(rsa->dmp1, rsa->d, r1, ctx))
          goto err;
  
      /* calculate d mod (q-1) */
      rsa->dmq1 = BN_new();
      if (rsa->dmq1 == NULL)
          goto err;
      if (!BN_mod(rsa->dmq1, rsa->d, r2, ctx))
          goto err;
  
      /* calculate inverse of q mod p */
      rsa->iqmp = BN_mod_inverse(NULL, rsa->q, rsa->p, ctx2);
  
      ret = 1;
   err:
      if (ctx)
          BN_CTX_end(ctx);
      BN_CTX_free(ctx);
      BN_CTX_free(ctx2);
  
      return ret;
  
  }
  
  int RSA_X931_generate_key_ex(RSA *rsa, int bits, const BIGNUM *e,
                               BN_GENCB *cb)
  {
      int ok = 0;
      BIGNUM *Xp = NULL, *Xq = NULL;
      BN_CTX *ctx = NULL;
  
      ctx = BN_CTX_new();
      if (ctx == NULL)
          goto error;
  
      BN_CTX_start(ctx);
      Xp = BN_CTX_get(ctx);
      Xq = BN_CTX_get(ctx);
      if (Xq == NULL)
          goto error;
      if (!BN_X931_generate_Xpq(Xp, Xq, bits, ctx))
          goto error;
  
      rsa->p = BN_new();
      rsa->q = BN_new();
      if (rsa->p == NULL || rsa->q == NULL)
          goto error;
  
      /* Generate two primes from Xp, Xq */
  
      if (!BN_X931_generate_prime_ex(rsa->p, NULL, NULL, NULL, NULL, Xp,
                                     e, ctx, cb))
          goto error;
  
      if (!BN_X931_generate_prime_ex(rsa->q, NULL, NULL, NULL, NULL, Xq,
                                     e, ctx, cb))
          goto error;
  
      /*
       * Since rsa->p and rsa->q are valid this call will just derive remaining
       * RSA components.
       */
  
      if (!RSA_X931_derive_ex(rsa, NULL, NULL, NULL, NULL,
                              NULL, NULL, NULL, NULL, NULL, NULL, e, cb))
          goto error;
  
      ok = 1;
  
   error:
      if (ctx)
          BN_CTX_end(ctx);
      BN_CTX_free(ctx);
  
      if (ok)
          return 1;
  
      return 0;
  
  }
  