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  * $DragonFly: src/usr.bin/newkey/generic.c,v 1.8 2008/06/05 18:06:33 swildner Exp $
  33  */
  34
  35 /*
  36  * Copyright (C) 1986, Sun Microsystems, Inc.
  37  */
  38
  39 #include <sys/file.h>
  40
  41 #include <err.h>
  42 #include <stdio.h>
  43 #include <stdlib.h>
  44
  45 #include <openssl/bn.h>
  46 #include <openssl/crypto.h>
  47 #include <openssl/err.h>
  48
  49 #include <rpc/rpc.h>
  50 #include <rpc/key_prot.h>
  51
  52 #include "externs.h"
  53
  54 static void     adjust(char[], char *);
  55 static BIGNUM   *itobn(long i);
  56
  57 /*
  58  * Generate a seed
  59  */
  60 static void
  61 getseed(char *seed, int seedsize, unsigned char *pass)
  62 {
  63         int i;
  64
  65         for (i = 0; i < seedsize; i++) {
  66                 seed[i] = (arc4random() & 0xff) ^ pass[i % 8];
  67         }
  68 }
  69
  70 static BIGNUM *
  71 itobn(long i)
  72 {
  73         BIGNUM *n = 0;
  74
  75         if ((n = BN_new()) == NULL)
  76                 errx(1, "could not create BIGNUM: %s",
  77                      ERR_error_string(ERR_get_error(), 0));
  78         BN_init(n);
  79         if (i > 0)
  80                 BN_add_word(n, (u_long)i);
  81         else
  82                 BN_sub_word(n, (u_long)(-i));
  83         return(n);
  84 }
  85
  86 /*
  87  * Generate a random public/secret key pair
  88  */
  89 void
  90 genkeys(char *public, char *secret, char *pass)
  91 {
  92 #define BASEBITS (8*sizeof (short) - 1)
  93 #define BASE (short)(1 << BASEBITS)
  94
  95         unsigned int i;
  96         short r;
  97         unsigned short seed[KEYSIZE/BASEBITS + 1];
  98         char *xkey;
  99
 100         BN_CTX *ctx;
 101         BIGNUM *pk, *sk, *tmp, *base, *root, *modulus;
 102
 103         pk = itobn(0);
 104         sk = itobn(0);
 105         tmp = itobn(0);
 106         base = itobn(BASE);
 107         root = itobn(PROOT);
 108         modulus = NULL;
 109         if (BN_hex2bn(&modulus, HEXMODULUS) == 0)
 110                 errx(1, "could not convert modulus to BIGNUM: %s",
 111                      ERR_error_string(ERR_get_error(), 0));
 112
 113         if ((ctx = BN_CTX_new()) == NULL)
 114                 errx(1, "could not create BN_CTX: %s",
 115                      ERR_error_string(ERR_get_error(), 0));
 116
 117         getseed((char *)seed, sizeof (seed), (u_char *)pass);
 118         for (i = 0; i < KEYSIZE/BASEBITS + 1; i++) {
 119                 r = seed[i] % BASE;
 120                 BN_zero(tmp);
 121                 BN_add_word(tmp, r);
 122                 BN_mul(sk, base, sk, ctx);
 123                 BN_add(sk, tmp, sk);
 124         }
 125         BN_zero(tmp);
 126         BN_div(tmp, sk, sk, modulus, ctx);
 127         BN_mod_exp(pk, root, sk, modulus, ctx);
 128
 129         if ((xkey = BN_bn2hex(sk)) == NULL)
 130                 errx(1, "could convert sk to hex: %s",
 131                      ERR_error_string(ERR_get_error(), 0));
 132         adjust(secret, xkey);
 133         OPENSSL_free(xkey);
 134
 135         if ((xkey = BN_bn2hex(pk)) == NULL)
 136                 errx(1, "could convert pk to hex: %s",
 137                      ERR_error_string(ERR_get_error(), 0));
 138         adjust(public, xkey);
 139         OPENSSL_free(xkey);
 140
 141         BN_free(base);
 142         BN_free(modulus);
 143         BN_free(pk);
 144         BN_free(sk);
 145         BN_free(root);
 146         BN_free(tmp);
 147 }
 148
 149 /*
 150  * Adjust the input key so that it is 0-filled on the left
 151  */
 152 static void
 153 adjust(char keyout[HEXKEYBYTES+1], char *keyin)
 154 {
 155         char *p;
 156         char *s;
 157
 158         for (p = keyin; *p; p++)
 159                 ;
 160         for (s = keyout + HEXKEYBYTES; p >= keyin; p--, s--) {
 161                 *s = *p;
 162         }
 163         while (s >= keyout) {
 164                 *s-- = '0';
 165         }
 166 }