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
rsa_public_encrypt(BIGNUM * out,BIGNUM * in,RSA * key)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
rsa_private_decrypt(BIGNUM * out,BIGNUM * in,RSA * key)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
rsa_generate_additional_parameters(RSA * rsa)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
189