AppleCSP/open_ssl/dh/dh_key.c

   1 /*
   2  * Copyright (c) 2000-2002 Apple Computer, Inc. All Rights Reserved.
   3  *
   4  * The contents of this file constitute Original Code as defined in and are
   5  * subject to the Apple Public Source License Version 1.2 (the 'License').
   6  * You may not use this file except in compliance with the License. Please obtain
   7  * a copy of the License at http://www.apple.com/publicsource and read it before
   8  * using this file.
   9  *
  10  * This Original Code and all software distributed under the License are
  11  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS
  12  * OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, INCLUDING WITHOUT
  13  * LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
  14  * PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. Please see the License for the
  15  * specific language governing rights and limitations under the License.
  16  */
  17
  18 /* crypto/dh/dh_key.c */
  19 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  20  * All rights reserved.
  21  *
  22  * This package is an SSL implementation written
  23  * by Eric Young (eay@cryptsoft.com).
  24  * The implementation was written so as to conform with Netscapes SSL.
  25  *
  26  * This library is free for commercial and non-commercial use as long as
  27  * the following conditions are aheared to.  The following conditions
  28  * apply to all code found in this distribution, be it the RC4, RSA,
  29  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
  30  * included with this distribution is covered by the same copyright terms
  31  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
  32  *
  33  * Copyright remains Eric Young's, and as such any Copyright notices in
  34  * the code are not to be removed.
  35  * If this package is used in a product, Eric Young should be given attribution
  36  * as the author of the parts of the library used.
  37  * This can be in the form of a textual message at program startup or
  38  * in documentation (online or textual) provided with the package.
  39  *
  40  * Redistribution and use in source and binary forms, with or without
  41  * modification, are permitted provided that the following conditions
  42  * are met:
  43  * 1. Redistributions of source code must retain the copyright
  44  *    notice, this list of conditions and the following disclaimer.
  45  * 2. Redistributions in binary form must reproduce the above copyright
  46  *    notice, this list of conditions and the following disclaimer in the
  47  *    documentation and/or other materials provided with the distribution.
  48  * 3. All advertising materials mentioning features or use of this software
  49  *    must display the following acknowledgement:
  50  *    "This product includes cryptographic software written by
  51  *     Eric Young (eay@cryptsoft.com)"
  52  *    The word 'cryptographic' can be left out if the rouines from the library
  53  *    being used are not cryptographic related :-).
  54  * 4. If you include any Windows specific code (or a derivative thereof) from
  55  *    the apps directory (application code) you must include an acknowledgement:
  56  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
  57  *
  58  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
  59  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  60  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  61  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  62  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  63  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  64  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  65  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  66  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  67  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  68  * SUCH DAMAGE.
  69  *
  70  * The licence and distribution terms for any publically available version or
  71  * derivative of this code cannot be changed.  i.e. this code cannot simply be
  72  * copied and put under another distribution licence
  73  * [including the GNU Public Licence.]
  74  */
  75
  76 #include <stdio.h>
  77 #include "cryptlib.h"
  78 #include <openssl/bn.h>
  79 #include <openssl/rand.h>
  80 #include <openssl/dh.h>
  81
  82 static int generate_key(DH *dh);
  83 static int compute_key(unsigned char *key, BIGNUM *pub_key, DH *dh);
  84 static int dh_bn_mod_exp(DH *dh, BIGNUM *r, BIGNUM *a, const BIGNUM *p,
  85                         const BIGNUM *m, BN_CTX *ctx,
  86                         BN_MONT_CTX *m_ctx);
  87 static int dh_init(DH *dh);
  88 static int dh_finish(DH *dh);
  89
  90 int DH_generate_key(DH *dh)
  91         {
  92         return dh->meth->generate_key(dh);
  93         }
  94
  95 int DH_compute_key(unsigned char *key, BIGNUM *pub_key, DH *dh)
  96         {
  97         return dh->meth->compute_key(key, pub_key, dh);
  98         }
  99
 100 static DH_METHOD dh_ossl = {
 101 "OpenSSL DH Method",
 102 generate_key,
 103 compute_key,
 104 dh_bn_mod_exp,
 105 dh_init,
 106 dh_finish,
 107 0,
 108 NULL
 109 };
 110
 111 DH_METHOD *DH_OpenSSL(void)
 112 {
 113         return &dh_ossl;
 114 }
 115
 116 static int generate_key(DH *dh)
 117         {
 118         int ok=0;
 119         BN_CTX ctx;
 120         BN_MONT_CTX *mont;
 121         BIGNUM *pub_key=NULL,*priv_key=NULL;
 122
 123         BN_CTX_init(&ctx);
 124
 125         if (dh->priv_key == NULL)
 126                 {
 127                 priv_key=BN_new();
 128                 if (priv_key == NULL) goto err;
 129                 do
 130                         if (!BN_rand_range(priv_key, dh->p)) goto err;
 131                 while (BN_is_zero(priv_key));
 132                 }
 133         else
 134                 priv_key=dh->priv_key;
 135
 136         if (dh->pub_key == NULL)
 137                 {
 138                 pub_key=BN_new();
 139                 if (pub_key == NULL) goto err;
 140                 }
 141         else
 142                 pub_key=dh->pub_key;
 143
 144         if ((dh->method_mont_p == NULL) && (dh->flags & DH_FLAG_CACHE_MONT_P))
 145                 {
 146                 if ((dh->method_mont_p=(char *)BN_MONT_CTX_new()) != NULL)
 147                         if (!BN_MONT_CTX_set((BN_MONT_CTX *)dh->method_mont_p,
 148                                 dh->p,&ctx)) goto err;
 149                 }
 150         mont=(BN_MONT_CTX *)dh->method_mont_p;
 151
 152         if (!dh->meth->bn_mod_exp(dh, pub_key,dh->g,priv_key,dh->p,&ctx,mont))
 153                                                                 goto err;
 154
 155         dh->pub_key=pub_key;
 156         dh->priv_key=priv_key;
 157         ok=1;
 158 err:
 159         if (ok != 1)
 160                 DHerr(DH_F_DH_GENERATE_KEY,ERR_R_BN_LIB);
 161
 162         if ((pub_key != NULL)  && (dh->pub_key == NULL))  BN_free(pub_key);
 163         if ((priv_key != NULL) && (dh->priv_key == NULL)) BN_free(priv_key);
 164         BN_CTX_free(&ctx);
 165         return(ok);
 166         }
 167
 168 static int compute_key(unsigned char *key, BIGNUM *pub_key, DH *dh)
 169         {
 170         BN_CTX ctx;
 171         BN_MONT_CTX *mont;
 172         BIGNUM *tmp;
 173         int ret= -1;
 174
 175         BN_CTX_init(&ctx);
 176         BN_CTX_start(&ctx);
 177         tmp = BN_CTX_get(&ctx);
 178
 179         if (dh->priv_key == NULL)
 180                 {
 181                 DHerr(DH_F_DH_COMPUTE_KEY,DH_R_NO_PRIVATE_VALUE);
 182                 goto err;
 183                 }
 184         if ((dh->method_mont_p == NULL) && (dh->flags & DH_FLAG_CACHE_MONT_P))
 185                 {
 186                 if ((dh->method_mont_p=(char *)BN_MONT_CTX_new()) != NULL)
 187                         if (!BN_MONT_CTX_set((BN_MONT_CTX *)dh->method_mont_p,
 188                                 dh->p,&ctx)) goto err;
 189                 }
 190
 191         mont=(BN_MONT_CTX *)dh->method_mont_p;
 192         if (!dh->meth->bn_mod_exp(dh, tmp,pub_key,dh->priv_key,dh->p,&ctx,mont))
 193                 {
 194                 DHerr(DH_F_DH_COMPUTE_KEY,ERR_R_BN_LIB);
 195                 goto err;
 196                 }
 197
 198         ret=BN_bn2bin(tmp,key);
 199 err:
 200         BN_CTX_end(&ctx);
 201         BN_CTX_free(&ctx);
 202         return(ret);
 203         }
 204
 205 static int dh_bn_mod_exp(DH *dh, BIGNUM *r, BIGNUM *a, const BIGNUM *p,
 206                         const BIGNUM *m, BN_CTX *ctx,
 207                         BN_MONT_CTX *m_ctx)
 208         {
 209         if (a->top == 1)
 210                 {
 211                 BN_ULONG A = a->d[0];
 212                 return BN_mod_exp_mont_word(r,A,p,m,ctx,m_ctx);
 213                 }
 214         else
 215                 return BN_mod_exp_mont(r,a,p,m,ctx,m_ctx);
 216         }
 217
 218
 219 static int dh_init(DH *dh)
 220         {
 221         dh->flags |= DH_FLAG_CACHE_MONT_P;
 222         return(1);
 223         }
 224
 225 static int dh_finish(DH *dh)
 226         {
 227         if(dh->method_mont_p)
 228                 BN_MONT_CTX_free((BN_MONT_CTX *)dh->method_mont_p);
 229         return(1);
 230         }