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