1*0Sstevel@tonic-gate /* crypto/dh/dh_check.c */ 2*0Sstevel@tonic-gate /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) 3*0Sstevel@tonic-gate * All rights reserved. 4*0Sstevel@tonic-gate * 5*0Sstevel@tonic-gate * This package is an SSL implementation written 6*0Sstevel@tonic-gate * by Eric Young (eay@cryptsoft.com). 7*0Sstevel@tonic-gate * The implementation was written so as to conform with Netscapes SSL. 8*0Sstevel@tonic-gate * 9*0Sstevel@tonic-gate * This library is free for commercial and non-commercial use as long as 10*0Sstevel@tonic-gate * the following conditions are aheared to. The following conditions 11*0Sstevel@tonic-gate * apply to all code found in this distribution, be it the RC4, RSA, 12*0Sstevel@tonic-gate * lhash, DES, etc., code; not just the SSL code. The SSL documentation 13*0Sstevel@tonic-gate * included with this distribution is covered by the same copyright terms 14*0Sstevel@tonic-gate * except that the holder is Tim Hudson (tjh@cryptsoft.com). 15*0Sstevel@tonic-gate * 16*0Sstevel@tonic-gate * Copyright remains Eric Young's, and as such any Copyright notices in 17*0Sstevel@tonic-gate * the code are not to be removed. 18*0Sstevel@tonic-gate * If this package is used in a product, Eric Young should be given attribution 19*0Sstevel@tonic-gate * as the author of the parts of the library used. 20*0Sstevel@tonic-gate * This can be in the form of a textual message at program startup or 21*0Sstevel@tonic-gate * in documentation (online or textual) provided with the package. 22*0Sstevel@tonic-gate * 23*0Sstevel@tonic-gate * Redistribution and use in source and binary forms, with or without 24*0Sstevel@tonic-gate * modification, are permitted provided that the following conditions 25*0Sstevel@tonic-gate * are met: 26*0Sstevel@tonic-gate * 1. Redistributions of source code must retain the copyright 27*0Sstevel@tonic-gate * notice, this list of conditions and the following disclaimer. 28*0Sstevel@tonic-gate * 2. Redistributions in binary form must reproduce the above copyright 29*0Sstevel@tonic-gate * notice, this list of conditions and the following disclaimer in the 30*0Sstevel@tonic-gate * documentation and/or other materials provided with the distribution. 31*0Sstevel@tonic-gate * 3. All advertising materials mentioning features or use of this software 32*0Sstevel@tonic-gate * must display the following acknowledgement: 33*0Sstevel@tonic-gate * "This product includes cryptographic software written by 34*0Sstevel@tonic-gate * Eric Young (eay@cryptsoft.com)" 35*0Sstevel@tonic-gate * The word 'cryptographic' can be left out if the rouines from the library 36*0Sstevel@tonic-gate * being used are not cryptographic related :-). 37*0Sstevel@tonic-gate * 4. If you include any Windows specific code (or a derivative thereof) from 38*0Sstevel@tonic-gate * the apps directory (application code) you must include an acknowledgement: 39*0Sstevel@tonic-gate * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" 40*0Sstevel@tonic-gate * 41*0Sstevel@tonic-gate * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND 42*0Sstevel@tonic-gate * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 43*0Sstevel@tonic-gate * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 44*0Sstevel@tonic-gate * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 45*0Sstevel@tonic-gate * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 46*0Sstevel@tonic-gate * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 47*0Sstevel@tonic-gate * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 48*0Sstevel@tonic-gate * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 49*0Sstevel@tonic-gate * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 50*0Sstevel@tonic-gate * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 51*0Sstevel@tonic-gate * SUCH DAMAGE. 52*0Sstevel@tonic-gate * 53*0Sstevel@tonic-gate * The licence and distribution terms for any publically available version or 54*0Sstevel@tonic-gate * derivative of this code cannot be changed. i.e. this code cannot simply be 55*0Sstevel@tonic-gate * copied and put under another distribution licence 56*0Sstevel@tonic-gate * [including the GNU Public Licence.] 57*0Sstevel@tonic-gate */ 58*0Sstevel@tonic-gate 59*0Sstevel@tonic-gate #include <stdio.h> 60*0Sstevel@tonic-gate #include "cryptlib.h" 61*0Sstevel@tonic-gate #include <openssl/bn.h> 62*0Sstevel@tonic-gate #include <openssl/dh.h> 63*0Sstevel@tonic-gate 64*0Sstevel@tonic-gate /* Check that p is a safe prime and 65*0Sstevel@tonic-gate * if g is 2, 3 or 5, check that is is a suitable generator 66*0Sstevel@tonic-gate * where 67*0Sstevel@tonic-gate * for 2, p mod 24 == 11 68*0Sstevel@tonic-gate * for 3, p mod 12 == 5 69*0Sstevel@tonic-gate * for 5, p mod 10 == 3 or 7 70*0Sstevel@tonic-gate * should hold. 71*0Sstevel@tonic-gate */ 72*0Sstevel@tonic-gate 73*0Sstevel@tonic-gate int DH_check(const DH *dh, int *ret) 74*0Sstevel@tonic-gate { 75*0Sstevel@tonic-gate int ok=0; 76*0Sstevel@tonic-gate BN_CTX *ctx=NULL; 77*0Sstevel@tonic-gate BN_ULONG l; 78*0Sstevel@tonic-gate BIGNUM *q=NULL; 79*0Sstevel@tonic-gate 80*0Sstevel@tonic-gate *ret=0; 81*0Sstevel@tonic-gate ctx=BN_CTX_new(); 82*0Sstevel@tonic-gate if (ctx == NULL) goto err; 83*0Sstevel@tonic-gate q=BN_new(); 84*0Sstevel@tonic-gate if (q == NULL) goto err; 85*0Sstevel@tonic-gate 86*0Sstevel@tonic-gate if (BN_is_word(dh->g,DH_GENERATOR_2)) 87*0Sstevel@tonic-gate { 88*0Sstevel@tonic-gate l=BN_mod_word(dh->p,24); 89*0Sstevel@tonic-gate if (l != 11) *ret|=DH_NOT_SUITABLE_GENERATOR; 90*0Sstevel@tonic-gate } 91*0Sstevel@tonic-gate #if 0 92*0Sstevel@tonic-gate else if (BN_is_word(dh->g,DH_GENERATOR_3)) 93*0Sstevel@tonic-gate { 94*0Sstevel@tonic-gate l=BN_mod_word(dh->p,12); 95*0Sstevel@tonic-gate if (l != 5) *ret|=DH_NOT_SUITABLE_GENERATOR; 96*0Sstevel@tonic-gate } 97*0Sstevel@tonic-gate #endif 98*0Sstevel@tonic-gate else if (BN_is_word(dh->g,DH_GENERATOR_5)) 99*0Sstevel@tonic-gate { 100*0Sstevel@tonic-gate l=BN_mod_word(dh->p,10); 101*0Sstevel@tonic-gate if ((l != 3) && (l != 7)) 102*0Sstevel@tonic-gate *ret|=DH_NOT_SUITABLE_GENERATOR; 103*0Sstevel@tonic-gate } 104*0Sstevel@tonic-gate else 105*0Sstevel@tonic-gate *ret|=DH_UNABLE_TO_CHECK_GENERATOR; 106*0Sstevel@tonic-gate 107*0Sstevel@tonic-gate if (!BN_is_prime(dh->p,BN_prime_checks,NULL,ctx,NULL)) 108*0Sstevel@tonic-gate *ret|=DH_CHECK_P_NOT_PRIME; 109*0Sstevel@tonic-gate else 110*0Sstevel@tonic-gate { 111*0Sstevel@tonic-gate if (!BN_rshift1(q,dh->p)) goto err; 112*0Sstevel@tonic-gate if (!BN_is_prime(q,BN_prime_checks,NULL,ctx,NULL)) 113*0Sstevel@tonic-gate *ret|=DH_CHECK_P_NOT_SAFE_PRIME; 114*0Sstevel@tonic-gate } 115*0Sstevel@tonic-gate ok=1; 116*0Sstevel@tonic-gate err: 117*0Sstevel@tonic-gate if (ctx != NULL) BN_CTX_free(ctx); 118*0Sstevel@tonic-gate if (q != NULL) BN_free(q); 119*0Sstevel@tonic-gate return(ok); 120*0Sstevel@tonic-gate } 121