crypto/rsa/rsa_crpt.c

   1 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
   2  * All rights reserved.
   3  *
   4  * This package is an SSL implementation written
   5  * by Eric Young (eay@cryptsoft.com).
   6  * The implementation was written so as to conform with Netscapes SSL.
   7  *
   8  * This library is free for commercial and non-commercial use as long as
   9  * the following conditions are aheared to.  The following conditions
  10  * apply to all code found in this distribution, be it the RC4, RSA,
  11  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
  12  * included with this distribution is covered by the same copyright terms
  13  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
  14  *
  15  * Copyright remains Eric Young's, and as such any Copyright notices in
  16  * the code are not to be removed.
  17  * If this package is used in a product, Eric Young should be given attribution
  18  * as the author of the parts of the library used.
  19  * This can be in the form of a textual message at program startup or
  20  * in documentation (online or textual) provided with the package.
  21  *
  22  * Redistribution and use in source and binary forms, with or without
  23  * modification, are permitted provided that the following conditions
  24  * are met:
  25  * 1. Redistributions of source code must retain the copyright
  26  *    notice, this list of conditions and the following disclaimer.
  27  * 2. Redistributions in binary form must reproduce the above copyright
  28  *    notice, this list of conditions and the following disclaimer in the
  29  *    documentation and/or other materials provided with the distribution.
  30  * 3. All advertising materials mentioning features or use of this software
  31  *    must display the following acknowledgement:
  32  *    "This product includes cryptographic software written by
  33  *     Eric Young (eay@cryptsoft.com)"
  34  *    The word 'cryptographic' can be left out if the rouines from the library
  35  *    being used are not cryptographic related :-).
  36  * 4. If you include any Windows specific code (or a derivative thereof) from
  37  *    the apps directory (application code) you must include an acknowledgement:
  38  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
  39  *
  40  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
  41  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  42  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  43  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  44  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  45  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  46  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  48  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  49  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  50  * SUCH DAMAGE.
  51  *
  52  * The licence and distribution terms for any publically available version or
  53  * derivative of this code cannot be changed.  i.e. this code cannot simply be
  54  * copied and put under another distribution licence
  55  * [including the GNU Public Licence.]
  56  */
  57
  58 #include <stdio.h>
  59 #include <openssl/crypto.h>
  60 #include "internal/cryptlib.h"
  61 #include <openssl/lhash.h>
  62 #include "internal/bn_int.h"
  63 #include <openssl/rsa.h>
  64 #include <openssl/rand.h>
  65
  66 int RSA_bits(const RSA *r)
  67 {
  68     return (BN_num_bits(r->n));
  69 }
  70
  71 int RSA_size(const RSA *r)
  72 {
  73     return (BN_num_bytes(r->n));
  74 }
  75
  76 int RSA_public_encrypt(int flen, const unsigned char *from, unsigned char *to,
  77                        RSA *rsa, int padding)
  78 {
  79     return (rsa->meth->rsa_pub_enc(flen, from, to, rsa, padding));
  80 }
  81
  82 int RSA_private_encrypt(int flen, const unsigned char *from,
  83                         unsigned char *to, RSA *rsa, int padding)
  84 {
  85     return (rsa->meth->rsa_priv_enc(flen, from, to, rsa, padding));
  86 }
  87
  88 int RSA_private_decrypt(int flen, const unsigned char *from,
  89                         unsigned char *to, RSA *rsa, int padding)
  90 {
  91     return (rsa->meth->rsa_priv_dec(flen, from, to, rsa, padding));
  92 }
  93
  94 int RSA_public_decrypt(int flen, const unsigned char *from, unsigned char *to,
  95                        RSA *rsa, int padding)
  96 {
  97     return (rsa->meth->rsa_pub_dec(flen, from, to, rsa, padding));
  98 }
  99
 100 int RSA_flags(const RSA *r)
 101 {
 102     return ((r == NULL) ? 0 : r->meth->flags);
 103 }
 104
 105 void RSA_blinding_off(RSA *rsa)
 106 {
 107     BN_BLINDING_free(rsa->blinding);
 108     rsa->blinding = NULL;
 109     rsa->flags &= ~RSA_FLAG_BLINDING;
 110     rsa->flags |= RSA_FLAG_NO_BLINDING;
 111 }
 112
 113 int RSA_blinding_on(RSA *rsa, BN_CTX *ctx)
 114 {
 115     int ret = 0;
 116
 117     if (rsa->blinding != NULL)
 118         RSA_blinding_off(rsa);
 119
 120     rsa->blinding = RSA_setup_blinding(rsa, ctx);
 121     if (rsa->blinding == NULL)
 122         goto err;
 123
 124     rsa->flags |= RSA_FLAG_BLINDING;
 125     rsa->flags &= ~RSA_FLAG_NO_BLINDING;
 126     ret = 1;
 127  err:
 128     return (ret);
 129 }
 130
 131 static BIGNUM *rsa_get_public_exp(const BIGNUM *d, const BIGNUM *p,
 132                                   const BIGNUM *q, BN_CTX *ctx)
 133 {
 134     BIGNUM *ret = NULL, *r0, *r1, *r2;
 135
 136     if (d == NULL || p == NULL || q == NULL)
 137         return NULL;
 138
 139     BN_CTX_start(ctx);
 140     r0 = BN_CTX_get(ctx);
 141     r1 = BN_CTX_get(ctx);
 142     r2 = BN_CTX_get(ctx);
 143     if (r2 == NULL)
 144         goto err;
 145
 146     if (!BN_sub(r1, p, BN_value_one()))
 147         goto err;
 148     if (!BN_sub(r2, q, BN_value_one()))
 149         goto err;
 150     if (!BN_mul(r0, r1, r2, ctx))
 151         goto err;
 152
 153     ret = BN_mod_inverse(NULL, d, r0, ctx);
 154  err:
 155     BN_CTX_end(ctx);
 156     return ret;
 157 }
 158
 159 BN_BLINDING *RSA_setup_blinding(RSA *rsa, BN_CTX *in_ctx)
 160 {
 161     BIGNUM *e;
 162     BN_CTX *ctx;
 163     BN_BLINDING *ret = NULL;
 164
 165     if (in_ctx == NULL) {
 166         if ((ctx = BN_CTX_new()) == NULL)
 167             return 0;
 168     } else
 169         ctx = in_ctx;
 170
 171     BN_CTX_start(ctx);
 172     e = BN_CTX_get(ctx);
 173     if (e == NULL) {
 174         RSAerr(RSA_F_RSA_SETUP_BLINDING, ERR_R_MALLOC_FAILURE);
 175         goto err;
 176     }
 177
 178     if (rsa->e == NULL) {
 179         e = rsa_get_public_exp(rsa->d, rsa->p, rsa->q, ctx);
 180         if (e == NULL) {
 181             RSAerr(RSA_F_RSA_SETUP_BLINDING, RSA_R_NO_PUBLIC_EXPONENT);
 182             goto err;
 183         }
 184     } else
 185         e = rsa->e;
 186
 187     if ((RAND_status() == 0) && rsa->d != NULL
 188         && bn_get_words(rsa->d) != NULL) {
 189         /*
 190          * if PRNG is not properly seeded, resort to secret exponent as
 191          * unpredictable seed
 192          */
 193         RAND_add(bn_get_words(rsa->d), bn_get_dmax(rsa->d) * sizeof(BN_ULONG),
 194                  0.0);
 195     }
 196
 197     {
 198         BIGNUM *local_n = NULL, *n;
 199         if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
 200             /* Set BN_FLG_CONSTTIME flag */
 201             local_n = n = BN_new();
 202             if (local_n == NULL) {
 203                 RSAerr(RSA_F_RSA_SETUP_BLINDING, ERR_R_MALLOC_FAILURE);
 204                 goto err;
 205             }
 206             BN_with_flags(n, rsa->n, BN_FLG_CONSTTIME);
 207         } else {
 208             n = rsa->n;
 209         }
 210
 211         ret = BN_BLINDING_create_param(NULL, e, n, ctx, rsa->meth->bn_mod_exp,
 212                                        rsa->_method_mod_n);
 213         /* We MUST free local_n before any further use of rsa->n */
 214         BN_free(local_n);
 215     }
 216     if (ret == NULL) {
 217         RSAerr(RSA_F_RSA_SETUP_BLINDING, ERR_R_BN_LIB);
 218         goto err;
 219     }
 220     CRYPTO_THREADID_current(BN_BLINDING_thread_id(ret));
 221  err:
 222     BN_CTX_end(ctx);
 223     if (ctx != in_ctx)
 224         BN_CTX_free(ctx);
 225     if (e != rsa->e)
 226         BN_free(e);
 227
 228     return ret;
 229 }