crypto/openssh/rsa.c

   1 /* $OpenBSD: rsa.c,v 1.32 2014/06/24 01:13:21 djm Exp $ */
   2 /*
   3  * Author: Tatu Ylonen <ylo@cs.hut.fi>
   4  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   5  *                    All rights reserved
   6  *
   7  * As far as I am concerned, the code I have written for this software
   8  * can be used freely for any purpose.  Any derived versions of this
   9  * software must be clearly marked as such, and if the derived work is
  10  * incompatible with the protocol description in the RFC file, it must be
  11  * called by a name other than "ssh" or "Secure Shell".
  12  *
  13  *
  14  * Copyright (c) 1999 Niels Provos.  All rights reserved.
  15  *
  16  * Redistribution and use in source and binary forms, with or without
  17  * modification, are permitted provided that the following conditions
  18  * are met:
  19  * 1. Redistributions of source code must retain the above copyright
  20  *    notice, this list of conditions and the following disclaimer.
  21  * 2. Redistributions in binary form must reproduce the above copyright
  22  *    notice, this list of conditions and the following disclaimer in the
  23  *    documentation and/or other materials provided with the distribution.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  26  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  27  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  28  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  29  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  30  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  31  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  32  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  33  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  34  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  35  *
  36  *
  37  * Description of the RSA algorithm can be found e.g. from the following
  38  * sources:
  39  *
  40  *   Bruce Schneier: Applied Cryptography.  John Wiley & Sons, 1994.
  41  *
  42  *   Jennifer Seberry and Josed Pieprzyk: Cryptography: An Introduction to
  43  *   Computer Security.  Prentice-Hall, 1989.
  44  *
  45  *   Man Young Rhee: Cryptography and Secure Data Communications.  McGraw-Hill,
  46  *   1994.
  47  *
  48  *   R. Rivest, A. Shamir, and L. M. Adleman: Cryptographic Communications
  49  *   System and Method.  US Patent 4,405,829, 1983.
  50  *
  51  *   Hans Riesel: Prime Numbers and Computer Methods for Factorization.
  52  *   Birkhauser, 1994.
  53  *
  54  *   The RSA Frequently Asked Questions document by RSA Data Security,
  55  *   Inc., 1995.
  56  *
  57  *   RSA in 3 lines of perl by Adam Back <aba@atlax.ex.ac.uk>, 1995, as
  58  * included below:
  59  *
  60  *     [gone - had to be deleted - what a pity]
  61  */
  62
  63 #include "includes.h"
  64
  65 #include <sys/types.h>
  66
  67 #include <stdarg.h>
  68 #include <string.h>
  69
  70 #include "rsa.h"
  71 #include "log.h"
  72 #include "ssherr.h"
  73
  74 int
  75 rsa_public_encrypt(BIGNUM *out, BIGNUM *in, RSA *key)
  76 {
  77         u_char *inbuf = NULL, *outbuf = NULL;
  78         int len, ilen, olen, r = SSH_ERR_INTERNAL_ERROR;
  79
  80         if (BN_num_bits(key->e) < 2 || !BN_is_odd(key->e))
  81                 return SSH_ERR_INVALID_ARGUMENT;
  82
  83         olen = BN_num_bytes(key->n);
  84         if ((outbuf = malloc(olen)) == NULL) {
  85                 r = SSH_ERR_ALLOC_FAIL;
  86                 goto out;
  87         }
  88
  89         ilen = BN_num_bytes(in);
  90         if ((inbuf = malloc(ilen)) == NULL) {
  91                 r = SSH_ERR_ALLOC_FAIL;
  92                 goto out;
  93         }
  94         BN_bn2bin(in, inbuf);
  95
  96         if ((len = RSA_public_encrypt(ilen, inbuf, outbuf, key,
  97             RSA_PKCS1_PADDING)) <= 0) {
  98                 r = SSH_ERR_LIBCRYPTO_ERROR;
  99                 goto out;
 100         }
 101
 102         if (BN_bin2bn(outbuf, len, out) == NULL) {
 103                 r = SSH_ERR_LIBCRYPTO_ERROR;
 104                 goto out;
 105         }
 106         r = 0;
 107
 108  out:
 109         if (outbuf != NULL) {
 110                 explicit_bzero(outbuf, olen);
 111                 free(outbuf);
 112         }
 113         if (inbuf != NULL) {
 114                 explicit_bzero(inbuf, ilen);
 115                 free(inbuf);
 116         }
 117         return r;
 118 }
 119
 120 int
 121 rsa_private_decrypt(BIGNUM *out, BIGNUM *in, RSA *key)
 122 {
 123         u_char *inbuf = NULL, *outbuf = NULL;
 124         int len, ilen, olen, r = SSH_ERR_INTERNAL_ERROR;
 125
 126         olen = BN_num_bytes(key->n);
 127         if ((outbuf = malloc(olen)) == NULL) {
 128                 r = SSH_ERR_ALLOC_FAIL;
 129                 goto out;
 130         }
 131
 132         ilen = BN_num_bytes(in);
 133         if ((inbuf = malloc(ilen)) == NULL) {
 134                 r = SSH_ERR_ALLOC_FAIL;
 135                 goto out;
 136         }
 137         BN_bn2bin(in, inbuf);
 138
 139         if ((len = RSA_private_decrypt(ilen, inbuf, outbuf, key,
 140             RSA_PKCS1_PADDING)) <= 0) {
 141                 r = SSH_ERR_LIBCRYPTO_ERROR;
 142                 goto out;
 143         } else if (BN_bin2bn(outbuf, len, out) == NULL) {
 144                 r = SSH_ERR_LIBCRYPTO_ERROR;
 145                 goto out;
 146         }
 147         r = 0;
 148  out:
 149         if (outbuf != NULL) {
 150                 explicit_bzero(outbuf, olen);
 151                 free(outbuf);
 152         }
 153         if (inbuf != NULL) {
 154                 explicit_bzero(inbuf, ilen);
 155                 free(inbuf);
 156         }
 157         return r;
 158 }
 159
 160 /* calculate p-1 and q-1 */
 161 int
 162 rsa_generate_additional_parameters(RSA *rsa)
 163 {
 164         BIGNUM *aux = NULL;
 165         BN_CTX *ctx = NULL;
 166         int r;
 167
 168         if ((ctx = BN_CTX_new()) == NULL)
 169                 return SSH_ERR_ALLOC_FAIL;
 170         if ((aux = BN_new()) == NULL) {
 171                 r = SSH_ERR_ALLOC_FAIL;
 172                 goto out;
 173         }
 174
 175         if ((BN_sub(aux, rsa->q, BN_value_one()) == 0) ||
 176             (BN_mod(rsa->dmq1, rsa->d, aux, ctx) == 0) ||
 177             (BN_sub(aux, rsa->p, BN_value_one()) == 0) ||
 178             (BN_mod(rsa->dmp1, rsa->d, aux, ctx) == 0)) {
 179                 r = SSH_ERR_LIBCRYPTO_ERROR;
 180                 goto out;
 181         }
 182         r = 0;
 183  out:
 184         BN_clear_free(aux);
 185         BN_CTX_free(ctx);
 186         return r;
 187 }
 188