usr.bin/newkey/generic.c

   1 /*
   2  * Sun RPC is a product of Sun Microsystems, Inc. and is provided for
   3  * unrestricted use provided that this legend is included on all tape
   4  * media and as a part of the software program in whole or part.  Users
   5  * may copy or modify Sun RPC without charge, but are not authorized
   6  * to license or distribute it to anyone else except as part of a product or
   7  * program developed by the user or with the express written consent of
   8  * Sun Microsystems, Inc.
   9  *
  10  * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
  11  * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
  12  * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
  13  *
  14  * Sun RPC is provided with no support and without any obligation on the
  15  * part of Sun Microsystems, Inc. to assist in its use, correction,
  16  * modification or enhancement.
  17  *
  18  * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
  19  * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
  20  * OR ANY PART THEREOF.
  21  *
  22  * In no event will Sun Microsystems, Inc. be liable for any lost revenue
  23  * or profits or other special, indirect and consequential damages, even if
  24  * Sun has been advised of the possibility of such damages.
  25  *
  26  * Sun Microsystems, Inc.
  27  * 2550 Garcia Avenue
  28  * Mountain View, California  94043
  29  *
  30  * @(#)generic.c 1.2 91/03/11 Copyr 1986 Sun Micro
  31  * $FreeBSD: src/usr.bin/newkey/generic.c,v 1.3.2.1 2001/07/04 22:32:20 kris Exp $
  32  */
  33
  34 /*
  35  * Copyright (C) 1986, Sun Microsystems, Inc.
  36  */
  37
  38 #include <sys/file.h>
  39
  40 #include <err.h>
  41 #include <stdio.h>
  42 #include <stdlib.h>
  43
  44 #include <openssl/bn.h>
  45 #include <openssl/crypto.h>
  46 #include <openssl/err.h>
  47
  48 #include <rpc/rpc.h>
  49 #include <rpc/key_prot.h>
  50
  51 #include "externs.h"
  52
  53 static void     adjust(char[], char *);
  54 static BIGNUM   *itobn(long i);
  55
  56 /*
  57  * Generate a seed
  58  */
  59 static void
  60 getseed(char *seed, int seedsize, unsigned char *pass)
  61 {
  62         int i;
  63
  64         for (i = 0; i < seedsize; i++) {
  65                 seed[i] = (arc4random() & 0xff) ^ pass[i % 8];
  66         }
  67 }
  68
  69 static BIGNUM *
  70 itobn(long i)
  71 {
  72         BIGNUM *n = NULL;
  73
  74         if ((n = BN_new()) == NULL)
  75                 errx(1, "could not create BIGNUM: %s",
  76                      ERR_error_string(ERR_get_error(), 0));
  77         BN_init(n);
  78         if (i > 0)
  79                 BN_add_word(n, (u_long)i);
  80         else
  81                 BN_sub_word(n, (u_long)(-i));
  82         return(n);
  83 }
  84
  85 /*
  86  * Generate a random public/secret key pair
  87  */
  88 void
  89 genkeys(char *public, char *secret, char *pass)
  90 {
  91 #define BASEBITS (8*sizeof (short) - 1)
  92 #define BASE (short)(1 << BASEBITS)
  93
  94         unsigned int i;
  95         short r;
  96         unsigned short seed[KEYSIZE/BASEBITS + 1];
  97         char *xkey;
  98
  99         BN_CTX *ctx;
 100         BIGNUM *pk, *sk, *tmp, *base, *root, *modulus;
 101
 102         pk = itobn(0);
 103         sk = itobn(0);
 104         tmp = itobn(0);
 105         base = itobn(BASE);
 106         root = itobn(PROOT);
 107         modulus = NULL;
 108         if (BN_hex2bn(&modulus, HEXMODULUS) == 0)
 109                 errx(1, "could not convert modulus to BIGNUM: %s",
 110                      ERR_error_string(ERR_get_error(), 0));
 111
 112         if ((ctx = BN_CTX_new()) == NULL)
 113                 errx(1, "could not create BN_CTX: %s",
 114                      ERR_error_string(ERR_get_error(), 0));
 115
 116         getseed((char *)seed, sizeof (seed), (u_char *)pass);
 117         for (i = 0; i < KEYSIZE/BASEBITS + 1; i++) {
 118                 r = seed[i] % BASE;
 119                 BN_zero(tmp);
 120                 BN_add_word(tmp, r);
 121                 BN_mul(sk, base, sk, ctx);
 122                 BN_add(sk, tmp, sk);
 123         }
 124         BN_zero(tmp);
 125         BN_div(tmp, sk, sk, modulus, ctx);
 126         BN_mod_exp(pk, root, sk, modulus, ctx);
 127
 128         if ((xkey = BN_bn2hex(sk)) == NULL)
 129                 errx(1, "could convert sk to hex: %s",
 130                      ERR_error_string(ERR_get_error(), 0));
 131         adjust(secret, xkey);
 132         OPENSSL_free(xkey);
 133
 134         if ((xkey = BN_bn2hex(pk)) == NULL)
 135                 errx(1, "could convert pk to hex: %s",
 136                      ERR_error_string(ERR_get_error(), 0));
 137         adjust(public, xkey);
 138         OPENSSL_free(xkey);
 139
 140         BN_free(base);
 141         BN_free(modulus);
 142         BN_free(pk);
 143         BN_free(sk);
 144         BN_free(root);
 145         BN_free(tmp);
 146 }
 147
 148 /*
 149  * Adjust the input key so that it is 0-filled on the left
 150  */
 151 static void
 152 adjust(char keyout[HEXKEYBYTES+1], char *keyin)
 153 {
 154         char *p;
 155         char *s;
 156
 157         for (p = keyin; *p; p++)
 158                 ;
 159         for (s = keyout + HEXKEYBYTES; p >= keyin; p--, s--) {
 160                 *s = *p;
 161         }
 162         while (s >= keyout) {
 163                 *s-- = '0';
 164         }
 165 }