crypto/openssl/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
  61  * are 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 #ifdef OPENSSL_FIPS
  71 # include <openssl/fips.h>
  72 extern int FIPS_rsa_x931_generate_key_ex(RSA *rsa, int bits, BIGNUM *e,
  73                                          BN_GENCB *cb);
  74 #endif
  75
  76 static int rsa_builtin_keygen(RSA *rsa, int bits, BIGNUM *e_value,
  77                               BN_GENCB *cb);
  78
  79 /*
  80  * NB: this wrapper would normally be placed in rsa_lib.c and the static
  81  * implementation would probably be in rsa_eay.c. Nonetheless, is kept here
  82  * so that we don't introduce a new linker dependency. Eg. any application
  83  * that wasn't previously linking object code related to key-generation won't
  84  * have to now just because key-generation is part of RSA_METHOD.
  85  */
  86 int RSA_generate_key_ex(RSA *rsa, int bits, BIGNUM *e_value, BN_GENCB *cb)
  87 {
  88 #ifdef OPENSSL_FIPS
  89     if (FIPS_mode() && !(rsa->meth->flags & RSA_FLAG_FIPS_METHOD)
  90         && !(rsa->flags & RSA_FLAG_NON_FIPS_ALLOW)) {
  91         RSAerr(RSA_F_RSA_GENERATE_KEY_EX, RSA_R_NON_FIPS_RSA_METHOD);
  92         return 0;
  93     }
  94 #endif
  95     if (rsa->meth->rsa_keygen)
  96         return rsa->meth->rsa_keygen(rsa, bits, e_value, cb);
  97 #ifdef OPENSSL_FIPS
  98     if (FIPS_mode())
  99         return FIPS_rsa_x931_generate_key_ex(rsa, bits, e_value, cb);
 100 #endif
 101     return rsa_builtin_keygen(rsa, bits, e_value, cb);
 102 }
 103
 104 static int rsa_builtin_keygen(RSA *rsa, int bits, BIGNUM *e_value,
 105                               BN_GENCB *cb)
 106 {
 107     BIGNUM *r0 = NULL, *r1 = NULL, *r2 = NULL, *r3 = NULL, *tmp;
 108     BIGNUM local_r0, local_d, local_p;
 109     BIGNUM *pr0, *d, *p;
 110     int bitsp, bitsq, ok = -1, n = 0;
 111     BN_CTX *ctx = NULL;
 112
 113     ctx = BN_CTX_new();
 114     if (ctx == NULL)
 115         goto err;
 116     BN_CTX_start(ctx);
 117     r0 = BN_CTX_get(ctx);
 118     r1 = BN_CTX_get(ctx);
 119     r2 = BN_CTX_get(ctx);
 120     r3 = BN_CTX_get(ctx);
 121     if (r3 == NULL)
 122         goto err;
 123
 124     bitsp = (bits + 1) / 2;
 125     bitsq = bits - bitsp;
 126
 127     /* We need the RSA components non-NULL */
 128     if (!rsa->n && ((rsa->n = BN_new()) == NULL))
 129         goto err;
 130     if (!rsa->d && ((rsa->d = BN_new()) == NULL))
 131         goto err;
 132     if (!rsa->e && ((rsa->e = BN_new()) == NULL))
 133         goto err;
 134     if (!rsa->p && ((rsa->p = BN_new()) == NULL))
 135         goto err;
 136     if (!rsa->q && ((rsa->q = BN_new()) == NULL))
 137         goto err;
 138     if (!rsa->dmp1 && ((rsa->dmp1 = BN_new()) == NULL))
 139         goto err;
 140     if (!rsa->dmq1 && ((rsa->dmq1 = BN_new()) == NULL))
 141         goto err;
 142     if (!rsa->iqmp && ((rsa->iqmp = BN_new()) == NULL))
 143         goto err;
 144
 145     BN_copy(rsa->e, e_value);
 146
 147     /* generate p and q */
 148     for (;;) {
 149         if (!BN_generate_prime_ex(rsa->p, bitsp, 0, NULL, NULL, cb))
 150             goto err;
 151         if (!BN_sub(r2, rsa->p, BN_value_one()))
 152             goto err;
 153         if (!BN_gcd(r1, r2, rsa->e, ctx))
 154             goto err;
 155         if (BN_is_one(r1))
 156             break;
 157         if (!BN_GENCB_call(cb, 2, n++))
 158             goto err;
 159     }
 160     if (!BN_GENCB_call(cb, 3, 0))
 161         goto err;
 162     for (;;) {
 163         /*
 164          * When generating ridiculously small keys, we can get stuck
 165          * continually regenerating the same prime values. Check for this and
 166          * bail if it happens 3 times.
 167          */
 168         unsigned int degenerate = 0;
 169         do {
 170             if (!BN_generate_prime_ex(rsa->q, bitsq, 0, NULL, NULL, cb))
 171                 goto err;
 172         } while ((BN_cmp(rsa->p, rsa->q) == 0) && (++degenerate < 3));
 173         if (degenerate == 3) {
 174             ok = 0;             /* we set our own err */
 175             RSAerr(RSA_F_RSA_BUILTIN_KEYGEN, RSA_R_KEY_SIZE_TOO_SMALL);
 176             goto err;
 177         }
 178         if (!BN_sub(r2, rsa->q, BN_value_one()))
 179             goto err;
 180         if (!BN_gcd(r1, r2, rsa->e, ctx))
 181             goto err;
 182         if (BN_is_one(r1))
 183             break;
 184         if (!BN_GENCB_call(cb, 2, n++))
 185             goto err;
 186     }
 187     if (!BN_GENCB_call(cb, 3, 1))
 188         goto err;
 189     if (BN_cmp(rsa->p, rsa->q) < 0) {
 190         tmp = rsa->p;
 191         rsa->p = rsa->q;
 192         rsa->q = tmp;
 193     }
 194
 195     /* calculate n */
 196     if (!BN_mul(rsa->n, rsa->p, rsa->q, ctx))
 197         goto err;
 198
 199     /* calculate d */
 200     if (!BN_sub(r1, rsa->p, BN_value_one()))
 201         goto err;               /* p-1 */
 202     if (!BN_sub(r2, rsa->q, BN_value_one()))
 203         goto err;               /* q-1 */
 204     if (!BN_mul(r0, r1, r2, ctx))
 205         goto err;               /* (p-1)(q-1) */
 206     if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
 207         pr0 = &local_r0;
 208         BN_with_flags(pr0, r0, BN_FLG_CONSTTIME);
 209     } else
 210         pr0 = r0;
 211     if (!BN_mod_inverse(rsa->d, rsa->e, pr0, ctx))
 212         goto err;               /* d */
 213
 214     /* set up d for correct BN_FLG_CONSTTIME flag */
 215     if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
 216         d = &local_d;
 217         BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
 218     } else
 219         d = rsa->d;
 220
 221     /* calculate d mod (p-1) */
 222     if (!BN_mod(rsa->dmp1, d, r1, ctx))
 223         goto err;
 224
 225     /* calculate d mod (q-1) */
 226     if (!BN_mod(rsa->dmq1, d, r2, ctx))
 227         goto err;
 228
 229     /* calculate inverse of q mod p */
 230     if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
 231         p = &local_p;
 232         BN_with_flags(p, rsa->p, BN_FLG_CONSTTIME);
 233     } else
 234         p = rsa->p;
 235     if (!BN_mod_inverse(rsa->iqmp, rsa->q, p, ctx))
 236         goto err;
 237
 238     ok = 1;
 239  err:
 240     if (ok == -1) {
 241         RSAerr(RSA_F_RSA_BUILTIN_KEYGEN, ERR_LIB_BN);
 242         ok = 0;
 243     }
 244     if (ctx != NULL) {
 245         BN_CTX_end(ctx);
 246         BN_CTX_free(ctx);
 247     }
 248
 249     return ok;
 250 }