summaryrefslogtreecommitdiff
path: root/rsa.c
blob: 5ecacef9030b89ed48d7359d9cf618240d5f7905 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
/* $OpenBSD: rsa.c,v 1.32 2014/06/24 01:13:21 djm Exp $ */
/*
 * Author: Tatu Ylonen <ylo@cs.hut.fi>
 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
 *                    All rights reserved
 *
 * As far as I am concerned, the code I have written for this software
 * can be used freely for any purpose.  Any derived versions of this
 * software must be clearly marked as such, and if the derived work is
 * incompatible with the protocol description in the RFC file, it must be
 * called by a name other than "ssh" or "Secure Shell".
 *
 *
 * Copyright (c) 1999 Niels Provos.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *
 * Description of the RSA algorithm can be found e.g. from the following
 * sources:
 *
 *   Bruce Schneier: Applied Cryptography.  John Wiley & Sons, 1994.
 *
 *   Jennifer Seberry and Josed Pieprzyk: Cryptography: An Introduction to
 *   Computer Security.  Prentice-Hall, 1989.
 *
 *   Man Young Rhee: Cryptography and Secure Data Communications.  McGraw-Hill,
 *   1994.
 *
 *   R. Rivest, A. Shamir, and L. M. Adleman: Cryptographic Communications
 *   System and Method.  US Patent 4,405,829, 1983.
 *
 *   Hans Riesel: Prime Numbers and Computer Methods for Factorization.
 *   Birkhauser, 1994.
 *
 *   The RSA Frequently Asked Questions document by RSA Data Security,
 *   Inc., 1995.
 *
 *   RSA in 3 lines of perl by Adam Back <aba@atlax.ex.ac.uk>, 1995, as
 * included below:
 *
 *     [gone - had to be deleted - what a pity]
 */

#include "includes.h"

#include <sys/types.h>

#include <stdarg.h>
#include <string.h>

#include "rsa.h"
#include "log.h"
#include "ssherr.h"

int
rsa_public_encrypt(BIGNUM *out, BIGNUM *in, RSA *key)
{
	u_char *inbuf = NULL, *outbuf = NULL;
	int len, ilen, olen, r = SSH_ERR_INTERNAL_ERROR;

	if (BN_num_bits(key->e) < 2 || !BN_is_odd(key->e))
		return SSH_ERR_INVALID_ARGUMENT;

	olen = BN_num_bytes(key->n);
	if ((outbuf = malloc(olen)) == NULL) {
		r = SSH_ERR_ALLOC_FAIL;
		goto out;
	}

	ilen = BN_num_bytes(in);
	if ((inbuf = malloc(ilen)) == NULL) {
		r = SSH_ERR_ALLOC_FAIL;
		goto out;
	}
	BN_bn2bin(in, inbuf);

	if ((len = RSA_public_encrypt(ilen, inbuf, outbuf, key,
	    RSA_PKCS1_PADDING)) <= 0) {
		r = SSH_ERR_LIBCRYPTO_ERROR;
		goto out;
	}

	if (BN_bin2bn(outbuf, len, out) == NULL) {
		r = SSH_ERR_LIBCRYPTO_ERROR;
		goto out;
	}
	r = 0;

 out:
	if (outbuf != NULL) {
		explicit_bzero(outbuf, olen);
		free(outbuf);
	}
	if (inbuf != NULL) {
		explicit_bzero(inbuf, ilen);
		free(inbuf);
	}
	return r;
}

int
rsa_private_decrypt(BIGNUM *out, BIGNUM *in, RSA *key)
{
	u_char *inbuf = NULL, *outbuf = NULL;
	int len, ilen, olen, r = SSH_ERR_INTERNAL_ERROR;

	olen = BN_num_bytes(key->n);
	if ((outbuf = malloc(olen)) == NULL) {
		r = SSH_ERR_ALLOC_FAIL;
		goto out;
	}

	ilen = BN_num_bytes(in);
	if ((inbuf = malloc(ilen)) == NULL) {
		r = SSH_ERR_ALLOC_FAIL;
		goto out;
	}
	BN_bn2bin(in, inbuf);

	if ((len = RSA_private_decrypt(ilen, inbuf, outbuf, key,
	    RSA_PKCS1_PADDING)) <= 0) {
		r = SSH_ERR_LIBCRYPTO_ERROR;
		goto out;
	} else if (BN_bin2bn(outbuf, len, out) == NULL) {
		r = SSH_ERR_LIBCRYPTO_ERROR;
		goto out;
	}
	r = 0;
 out:
	if (outbuf != NULL) {
		explicit_bzero(outbuf, olen);
		free(outbuf);
	}
	if (inbuf != NULL) {
		explicit_bzero(inbuf, ilen);
		free(inbuf);
	}
	return r;
}

/* calculate p-1 and q-1 */
int
rsa_generate_additional_parameters(RSA *rsa)
{
	BIGNUM *aux = NULL;
	BN_CTX *ctx = NULL;
	int r;

	if ((ctx = BN_CTX_new()) == NULL)
		return SSH_ERR_ALLOC_FAIL;
	if ((aux = BN_new()) == NULL) {
		r = SSH_ERR_ALLOC_FAIL;
		goto out;
	}

	if ((BN_sub(aux, rsa->q, BN_value_one()) == 0) ||
	    (BN_mod(rsa->dmq1, rsa->d, aux, ctx) == 0) ||
	    (BN_sub(aux, rsa->p, BN_value_one()) == 0) ||
	    (BN_mod(rsa->dmp1, rsa->d, aux, ctx) == 0)) {
		r = SSH_ERR_LIBCRYPTO_ERROR;
		goto out;
	}
	r = 0;
 out:
	BN_clear_free(aux);
	BN_CTX_free(ctx);
	return r;
}