rsa.c revision 295367 
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
74int
75rsa_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
120int
121rsa_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 */
161int
162rsa_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
189