1/* crypto/dh/dh_key.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#include <stdio.h> 60#include <openssl/err.h> 61#include <openssl/bn.h> 62#ifndef OPENSSL_NO_RAND 63#include <openssl/rand.h> 64#endif 65#ifndef OPENSSL_NO_DH 66#include <openssl/dh.h> 67 68#ifdef OPENSSL_FIPS 69 70static int generate_key(DH *dh); 71static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh); 72static int dh_bn_mod_exp(const DH *dh, BIGNUM *r, 73 const BIGNUM *a, const BIGNUM *p, 74 const BIGNUM *m, BN_CTX *ctx, 75 BN_MONT_CTX *m_ctx); 76static int dh_init(DH *dh); 77static int dh_finish(DH *dh); 78 79int DH_generate_key(DH *dh) 80 { 81 return dh->meth->generate_key(dh); 82 } 83 84int DH_compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh) 85 { 86 return dh->meth->compute_key(key, pub_key, dh); 87 } 88 89static DH_METHOD dh_ossl = { 90"OpenSSL DH Method", 91generate_key, 92compute_key, 93dh_bn_mod_exp, 94dh_init, 95dh_finish, 960, 97NULL 98}; 99 100const DH_METHOD *DH_OpenSSL(void) 101{ 102 return &dh_ossl; 103} 104 105static int generate_key(DH *dh) 106 { 107 int ok=0; 108 int generate_new_key=0; 109 unsigned l; 110 BN_CTX *ctx; 111 BN_MONT_CTX *mont; 112 BIGNUM *pub_key=NULL,*priv_key=NULL; 113 114 ctx = BN_CTX_new(); 115 if (ctx == NULL) goto err; 116 117 if (dh->priv_key == NULL) 118 { 119 priv_key=BN_new(); 120 if (priv_key == NULL) goto err; 121 generate_new_key=1; 122 } 123 else 124 priv_key=dh->priv_key; 125 126 if (dh->pub_key == NULL) 127 { 128 pub_key=BN_new(); 129 if (pub_key == NULL) goto err; 130 } 131 else 132 pub_key=dh->pub_key; 133 134 if ((dh->method_mont_p == NULL) && (dh->flags & DH_FLAG_CACHE_MONT_P)) 135 { 136 if ((dh->method_mont_p=(char *)BN_MONT_CTX_new()) != NULL) 137 if (!BN_MONT_CTX_set((BN_MONT_CTX *)dh->method_mont_p, 138 dh->p,ctx)) goto err; 139 } 140 mont=(BN_MONT_CTX *)dh->method_mont_p; 141 142 if (generate_new_key) 143 { 144 l = dh->length ? dh->length : BN_num_bits(dh->p)-1; /* secret exponent length */ 145 if (!BN_rand(priv_key, l, 0, 0)) goto err; 146 } 147 if (!dh->meth->bn_mod_exp(dh, pub_key, dh->g, priv_key,dh->p,ctx,mont)) 148 goto err; 149 150 dh->pub_key=pub_key; 151 dh->priv_key=priv_key; 152 ok=1; 153err: 154 if (ok != 1) 155 DHerr(DH_F_DH_GENERATE_KEY,ERR_R_BN_LIB); 156 157 if ((pub_key != NULL) && (dh->pub_key == NULL)) BN_free(pub_key); 158 if ((priv_key != NULL) && (dh->priv_key == NULL)) BN_free(priv_key); 159 BN_CTX_free(ctx); 160 return(ok); 161 } 162 163static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh) 164 { 165 BN_CTX *ctx; 166 BN_MONT_CTX *mont; 167 BIGNUM *tmp; 168 int ret= -1; 169 170 ctx = BN_CTX_new(); 171 if (ctx == NULL) goto err; 172 BN_CTX_start(ctx); 173 tmp = BN_CTX_get(ctx); 174 175 if (dh->priv_key == NULL) 176 { 177 DHerr(DH_F_DH_COMPUTE_KEY,DH_R_NO_PRIVATE_VALUE); 178 goto err; 179 } 180 if ((dh->method_mont_p == NULL) && (dh->flags & DH_FLAG_CACHE_MONT_P)) 181 { 182 if ((dh->method_mont_p=(char *)BN_MONT_CTX_new()) != NULL) 183 if (!BN_MONT_CTX_set((BN_MONT_CTX *)dh->method_mont_p, 184 dh->p,ctx)) goto err; 185 } 186 187 mont=(BN_MONT_CTX *)dh->method_mont_p; 188 if (!dh->meth->bn_mod_exp(dh, tmp, pub_key, dh->priv_key,dh->p,ctx,mont)) 189 { 190 DHerr(DH_F_DH_COMPUTE_KEY,ERR_R_BN_LIB); 191 goto err; 192 } 193 194 ret=BN_bn2bin(tmp,key); 195err: 196 BN_CTX_end(ctx); 197 BN_CTX_free(ctx); 198 return(ret); 199 } 200 201static int dh_bn_mod_exp(const DH *dh, BIGNUM *r, 202 const BIGNUM *a, const BIGNUM *p, 203 const BIGNUM *m, BN_CTX *ctx, 204 BN_MONT_CTX *m_ctx) 205 { 206 if (a->top == 1) 207 { 208 BN_ULONG A = a->d[0]; 209 return BN_mod_exp_mont_word(r,A,p,m,ctx,m_ctx); 210 } 211 else 212 return BN_mod_exp_mont(r,a,p,m,ctx,m_ctx); 213 } 214 215 216static int dh_init(DH *dh) 217 { 218 dh->flags |= DH_FLAG_CACHE_MONT_P; 219 return(1); 220 } 221 222static int dh_finish(DH *dh) 223 { 224 if(dh->method_mont_p) 225 BN_MONT_CTX_free((BN_MONT_CTX *)dh->method_mont_p); 226 return(1); 227 } 228 229#endif 230#endif 231