crypto/rsa/rsa_gen.c

   1 /* crypto/rsa/rsa_gen.c */
   2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
   3  * All rights reserved.
   4  *
   5  * This package is an SSL implementation written
   6  * by Eric Young (eay@cryptsoft.com).
   7  * The implementation was written so as to conform with Netscapes SSL.
   8  *
   9  * This library is free for commercial and non-commercial use as long as
  10  * the following conditions are aheared to.  The following conditions
  11  * apply to all code found in this distribution, be it the RC4, RSA,
  12  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
  13  * included with this distribution is covered by the same copyright terms
  14  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
  15  *
  16  * Copyright remains Eric Young's, and as such any Copyright notices in
  17  * the code are not to be removed.
  18  * If this package is used in a product, Eric Young should be given attribution
  19  * as the author of the parts of the library used.
  20  * This can be in the form of a textual message at program startup or
  21  * in documentation (online or textual) provided with the package.
  22  *
  23  * Redistribution and use in source and binary forms, with or without
  24  * modification, are permitted provided that the following conditions
  25  * are met:
  26  * 1. Redistributions of source code must retain the copyright
  27  *    notice, this list of conditions and the following disclaimer.
  28  * 2. Redistributions in binary form must reproduce the above copyright
  29  *    notice, this list of conditions and the following disclaimer in the
  30  *    documentation and/or other materials provided with the distribution.
  31  * 3. All advertising materials mentioning features or use of this software
  32  *    must display the following acknowledgement:
  33  *    "This product includes cryptographic software written by
  34  *     Eric Young (eay@cryptsoft.com)"
  35  *    The word 'cryptographic' can be left out if the rouines from the library
  36  *    being used are not cryptographic related :-).
  37  * 4. If you include any Windows specific code (or a derivative thereof) from
  38  *    the apps directory (application code) you must include an acknowledgement:
  39  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
  40  *
  41  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
  42  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  43  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  44  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  45  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  46  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  47  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  49  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  50  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  51  * SUCH DAMAGE.
  52  *
  53  * The licence and distribution terms for any publically available version or
  54  * derivative of this code cannot be changed.  i.e. this code cannot simply be
  55  * copied and put under another distribution licence
  56  * [including the GNU Public Licence.]
  57  */
  58
  59
  60 /* NB: these functions have been "upgraded", the deprecated versions (which are
  61  * compatibility wrappers using these functions) are in rsa_depr.c.
  62  * - Geoff
  63  */
  64
  65 #include <stdio.h>
  66 #include <time.h>
  67 #include "cryptlib.h"
  68 #include <openssl/bn.h>
  69 #include <openssl/rsa.h>
  70
  71 static int rsa_builtin_keygen(RSA *rsa, int bits, BIGNUM *e_value, BN_GENCB *cb);
  72
  73 /* NB: this wrapper would normally be placed in rsa_lib.c and the static
  74  * implementation would probably be in rsa_eay.c. Nonetheless, is kept here so
  75  * that we don't introduce a new linker dependency. Eg. any application that
  76  * wasn't previously linking object code related to key-generation won't have to
  77  * now just because key-generation is part of RSA_METHOD. */
  78 int RSA_generate_key_ex(RSA *rsa, int bits, BIGNUM *e_value, BN_GENCB *cb)
  79         {
  80         if(rsa->meth->rsa_keygen)
  81                 return rsa->meth->rsa_keygen(rsa, bits, e_value, cb);
  82         return rsa_builtin_keygen(rsa, bits, e_value, cb);
  83         }
  84
  85 static int rsa_builtin_keygen(RSA *rsa, int bits, BIGNUM *e_value, BN_GENCB *cb)
  86         {
  87         BIGNUM *r0=NULL,*r1=NULL,*r2=NULL,*r3=NULL,*tmp;
  88         int bitsp,bitsq,ok= -1,n=0;
  89         BN_CTX *ctx=NULL;
  90
  91         ctx=BN_CTX_new();
  92         if (ctx == NULL) goto err;
  93         BN_CTX_start(ctx);
  94         r0 = BN_CTX_get(ctx);
  95         r1 = BN_CTX_get(ctx);
  96         r2 = BN_CTX_get(ctx);
  97         r3 = BN_CTX_get(ctx);
  98         if (r3 == NULL) goto err;
  99
 100         bitsp=(bits+1)/2;
 101         bitsq=bits-bitsp;
 102
 103         /* We need the RSA components non-NULL */
 104         if(!rsa->n && ((rsa->n=BN_new()) == NULL)) goto err;
 105         if(!rsa->d && ((rsa->d=BN_new()) == NULL)) goto err;
 106         if(!rsa->e && ((rsa->e=BN_new()) == NULL)) goto err;
 107         if(!rsa->p && ((rsa->p=BN_new()) == NULL)) goto err;
 108         if(!rsa->q && ((rsa->q=BN_new()) == NULL)) goto err;
 109         if(!rsa->dmp1 && ((rsa->dmp1=BN_new()) == NULL)) goto err;
 110         if(!rsa->dmq1 && ((rsa->dmq1=BN_new()) == NULL)) goto err;
 111         if(!rsa->iqmp && ((rsa->iqmp=BN_new()) == NULL)) goto err;
 112
 113         BN_copy(rsa->e, e_value);
 114
 115         /* generate p and q */
 116         for (;;)
 117                 {
 118                 if(!BN_generate_prime_ex(rsa->p, bitsp, 0, NULL, NULL, cb))
 119                         goto err;
 120                 if (!BN_sub(r2,rsa->p,BN_value_one())) goto err;
 121                 if (!BN_gcd(r1,r2,rsa->e,ctx)) goto err;
 122                 if (BN_is_one(r1)) break;
 123                 if(!BN_GENCB_call(cb, 2, n++))
 124                         goto err;
 125                 }
 126         if(!BN_GENCB_call(cb, 3, 0))
 127                 goto err;
 128         for (;;)
 129                 {
 130                 /* When generating ridiculously small keys, we can get stuck
 131                  * continually regenerating the same prime values. Check for
 132                  * this and bail if it happens 3 times. */
 133                 unsigned int degenerate = 0;
 134                 do
 135                         {
 136                         if(!BN_generate_prime_ex(rsa->q, bitsq, 0, NULL, NULL, cb))
 137                                 goto err;
 138                         } while((BN_cmp(rsa->p, rsa->q) == 0) && (++degenerate < 3));
 139                 if(degenerate == 3)
 140                         {
 141                         ok = 0; /* we set our own err */
 142                         RSAerr(RSA_F_RSA_GENERATE_KEY,RSA_R_KEY_SIZE_TOO_SMALL);
 143                         goto err;
 144                         }
 145                 if (!BN_sub(r2,rsa->q,BN_value_one())) goto err;
 146                 if (!BN_gcd(r1,r2,rsa->e,ctx)) goto err;
 147                 if (BN_is_one(r1))
 148                         break;
 149                 if(!BN_GENCB_call(cb, 2, n++))
 150                         goto err;
 151                 }
 152         if(!BN_GENCB_call(cb, 3, 1))
 153                 goto err;
 154         if (BN_cmp(rsa->p,rsa->q) < 0)
 155                 {
 156                 tmp=rsa->p;
 157                 rsa->p=rsa->q;
 158                 rsa->q=tmp;
 159                 }
 160
 161         /* calculate n */
 162         if (!BN_mul(rsa->n,rsa->p,rsa->q,ctx)) goto err;
 163
 164         /* calculate d */
 165         if (!BN_sub(r1,rsa->p,BN_value_one())) goto err;        /* p-1 */
 166         if (!BN_sub(r2,rsa->q,BN_value_one())) goto err;        /* q-1 */
 167         if (!BN_mul(r0,r1,r2,ctx)) goto err;    /* (p-1)(q-1) */
 168         if (!BN_mod_inverse(rsa->d,rsa->e,r0,ctx)) goto err;    /* d */
 169
 170         /* calculate d mod (p-1) */
 171         if (!BN_mod(rsa->dmp1,rsa->d,r1,ctx)) goto err;
 172
 173         /* calculate d mod (q-1) */
 174         if (!BN_mod(rsa->dmq1,rsa->d,r2,ctx)) goto err;
 175
 176         /* calculate inverse of q mod p */
 177         if (!BN_mod_inverse(rsa->iqmp,rsa->q,rsa->p,ctx)) goto err;
 178
 179         ok=1;
 180 err:
 181         if (ok == -1)
 182                 {
 183                 RSAerr(RSA_F_RSA_GENERATE_KEY,ERR_LIB_BN);
 184                 ok=0;
 185                 }
 186         BN_CTX_end(ctx);
 187         BN_CTX_free(ctx);
 188
 189         return ok;
 190         }
 191