lib/libcrypto/rsa/rsa_crpt.c

   1 /* $OpenBSD: rsa_crpt.c,v 1.19 2018/02/18 12:52:13 tb Exp $ */
   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 #include <stdio.h>
  60
  61 #include <openssl/opensslconf.h>
  62
  63 #include <openssl/bn.h>
  64 #include <openssl/crypto.h>
  65 #include <openssl/err.h>
  66 #include <openssl/lhash.h>
  67 #include <openssl/rsa.h>
  68
  69 #include "bn_lcl.h"
  70
  71 #ifndef OPENSSL_NO_ENGINE
  72 #include <openssl/engine.h>
  73 #endif
  74
  75 int
  76 RSA_bits(const RSA *r)
  77 {
  78         return BN_num_bits(r->n);
  79 }
  80
  81 int
  82 RSA_size(const RSA *r)
  83 {
  84         return BN_num_bytes(r->n);
  85 }
  86
  87 int
  88 RSA_public_encrypt(int flen, const unsigned char *from, unsigned char *to,
  89     RSA *rsa, int padding)
  90 {
  91         return rsa->meth->rsa_pub_enc(flen, from, to, rsa, padding);
  92 }
  93
  94 int
  95 RSA_private_encrypt(int flen, const unsigned char *from, unsigned char *to,
  96     RSA *rsa, int padding)
  97 {
  98         return rsa->meth->rsa_priv_enc(flen, from, to, rsa, padding);
  99 }
 100
 101 int
 102 RSA_private_decrypt(int flen, const unsigned char *from, unsigned char *to,
 103     RSA *rsa, int padding)
 104 {
 105         return rsa->meth->rsa_priv_dec(flen, from, to, rsa, padding);
 106 }
 107
 108 int
 109 RSA_public_decrypt(int flen, const unsigned char *from, unsigned char *to,
 110     RSA *rsa, int padding)
 111 {
 112         return rsa->meth->rsa_pub_dec(flen, from, to, rsa, padding);
 113 }
 114
 115 int
 116 RSA_flags(const RSA *r)
 117 {
 118         return r == NULL ? 0 : r->meth->flags;
 119 }
 120
 121 void
 122 RSA_blinding_off(RSA *rsa)
 123 {
 124         BN_BLINDING_free(rsa->blinding);
 125         rsa->blinding = NULL;
 126         rsa->flags |= RSA_FLAG_NO_BLINDING;
 127 }
 128
 129 int
 130 RSA_blinding_on(RSA *rsa, BN_CTX *ctx)
 131 {
 132         int ret = 0;
 133
 134         if (rsa->blinding != NULL)
 135                 RSA_blinding_off(rsa);
 136
 137         rsa->blinding = RSA_setup_blinding(rsa, ctx);
 138         if (rsa->blinding == NULL)
 139                 goto err;
 140
 141         rsa->flags &= ~RSA_FLAG_NO_BLINDING;
 142         ret = 1;
 143 err:
 144         return (ret);
 145 }
 146
 147 static BIGNUM *
 148 rsa_get_public_exp(const BIGNUM *d, const BIGNUM *p, const BIGNUM *q,
 149     BN_CTX *ctx)
 150 {
 151         BIGNUM *ret = NULL, *r0, *r1, *r2;
 152
 153         if (d == NULL || p == NULL || q == NULL)
 154                 return NULL;
 155
 156         BN_CTX_start(ctx);
 157         if ((r0 = BN_CTX_get(ctx)) == NULL)
 158                 goto err;
 159         if ((r1 = BN_CTX_get(ctx)) == NULL)
 160                 goto err;
 161         if ((r2 = BN_CTX_get(ctx)) == NULL)
 162                 goto err;
 163
 164         if (!BN_sub(r1, p, BN_value_one()))
 165                 goto err;
 166         if (!BN_sub(r2, q, BN_value_one()))
 167                 goto err;
 168         if (!BN_mul(r0, r1, r2, ctx))
 169                 goto err;
 170
 171         ret = BN_mod_inverse_ct(NULL, d, r0, ctx);
 172 err:
 173         BN_CTX_end(ctx);
 174         return ret;
 175 }
 176
 177 BN_BLINDING *
 178 RSA_setup_blinding(RSA *rsa, BN_CTX *in_ctx)
 179 {
 180         BIGNUM *e;
 181         BIGNUM n;
 182         BN_CTX *ctx;
 183         BN_BLINDING *ret = NULL;
 184
 185         if (in_ctx == NULL) {
 186                 if ((ctx = BN_CTX_new()) == NULL)
 187                         return 0;
 188         } else
 189                 ctx = in_ctx;
 190
 191         BN_CTX_start(ctx);
 192
 193         if (rsa->e == NULL) {
 194                 e = rsa_get_public_exp(rsa->d, rsa->p, rsa->q, ctx);
 195                 if (e == NULL) {
 196                         RSAerror(RSA_R_NO_PUBLIC_EXPONENT);
 197                         goto err;
 198                 }
 199         } else
 200                 e = rsa->e;
 201
 202         BN_init(&n);
 203         BN_with_flags(&n, rsa->n, BN_FLG_CONSTTIME);
 204
 205         ret = BN_BLINDING_create_param(NULL, e, &n, ctx, rsa->meth->bn_mod_exp,
 206             rsa->_method_mod_n);
 207
 208         if (ret == NULL) {
 209                 RSAerror(ERR_R_BN_LIB);
 210                 goto err;
 211         }
 212         CRYPTO_THREADID_current(BN_BLINDING_thread_id(ret));
 213 err:
 214         BN_CTX_end(ctx);
 215         if (in_ctx == NULL)
 216                 BN_CTX_free(ctx);
 217         if (rsa->e == NULL)
 218                 BN_free(e);
 219
 220         return ret;
 221 }