rsa_lib.c revision 296465 
1/* crypto/rsa/rsa_lib.c */
2/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3 * All rights reserved.
4 *
5 * This package is an SSL implementation written
6 * by Eric Young (eay@cryptsoft.com).
7 * The implementation was written so as to conform with Netscapes SSL.
8 *
9 * This library is free for commercial and non-commercial use as long as
10 * the following conditions are aheared to.  The following conditions
11 * apply to all code found in this distribution, be it the RC4, RSA,
12 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
13 * included with this distribution is covered by the same copyright terms
14 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
15 *
16 * Copyright remains Eric Young's, and as such any Copyright notices in
17 * the code are not to be removed.
18 * If this package is used in a product, Eric Young should be given attribution
19 * as the author of the parts of the library used.
20 * This can be in the form of a textual message at program startup or
21 * in documentation (online or textual) provided with the package.
22 *
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
25 * are met:
26 * 1. Redistributions of source code must retain the copyright
27 *    notice, this list of conditions and the following disclaimer.
28 * 2. Redistributions in binary form must reproduce the above copyright
29 *    notice, this list of conditions and the following disclaimer in the
30 *    documentation and/or other materials provided with the distribution.
31 * 3. All advertising materials mentioning features or use of this software
32 *    must display the following acknowledgement:
33 *    "This product includes cryptographic software written by
34 *     Eric Young (eay@cryptsoft.com)"
35 *    The word 'cryptographic' can be left out if the rouines from the library
36 *    being used are not cryptographic related :-).
37 * 4. If you include any Windows specific code (or a derivative thereof) from
38 *    the apps directory (application code) you must include an acknowledgement:
39 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40 *
41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51 * SUCH DAMAGE.
52 *
53 * The licence and distribution terms for any publically available version or
54 * derivative of this code cannot be changed.  i.e. this code cannot simply be
55 * copied and put under another distribution licence
56 * [including the GNU Public Licence.]
57 */
58
59#include <stdio.h>
60#include <openssl/crypto.h>
61#include "cryptlib.h"
62#include <openssl/lhash.h>
63#include <openssl/bn.h>
64#include <openssl/rsa.h>
65#include <openssl/rand.h>
66#ifndef OPENSSL_NO_ENGINE
67# include <openssl/engine.h>
68#endif
69
70int RSA_public_encrypt(int flen, const unsigned char *from, unsigned char *to,
71                       RSA *rsa, int padding)
72{
73    return (rsa->meth->rsa_pub_enc(flen, from, to, rsa, padding));
74}
75
76int RSA_private_encrypt(int flen, const unsigned char *from,
77                        unsigned char *to, RSA *rsa, int padding)
78{
79#ifdef OPENSSL_FIPS
80    if (FIPS_mode() && !(rsa->flags & RSA_FLAG_NON_FIPS_ALLOW)) {
81        RSAerr(RSA_F_RSA_PRIVATE_ENCRYPT,
82               RSA_R_OPERATION_NOT_ALLOWED_IN_FIPS_MODE);
83        return 0;
84    }
85#endif
86    return (rsa->meth->rsa_priv_enc(flen, from, to, rsa, padding));
87}
88
89int RSA_private_decrypt(int flen, const unsigned char *from,
90                        unsigned char *to, RSA *rsa, int padding)
91{
92    return (rsa->meth->rsa_priv_dec(flen, from, to, rsa, padding));
93}
94
95int RSA_public_decrypt(int flen, const unsigned char *from, unsigned char *to,
96                       RSA *rsa, int padding)
97{
98#ifdef OPENSSL_FIPS
99    if (FIPS_mode() && !(rsa->flags & RSA_FLAG_NON_FIPS_ALLOW)) {
100        RSAerr(RSA_F_RSA_PUBLIC_DECRYPT,
101               RSA_R_OPERATION_NOT_ALLOWED_IN_FIPS_MODE);
102        return 0;
103    }
104#endif
105    return (rsa->meth->rsa_pub_dec(flen, from, to, rsa, padding));
106}
107
108int RSA_size(const RSA *r)
109{
110    return (BN_num_bytes(r->n));
111}
112
113void RSA_blinding_off(RSA *rsa)
114{
115    if (rsa->blinding != NULL) {
116        BN_BLINDING_free(rsa->blinding);
117        rsa->blinding = NULL;
118    }
119    rsa->flags &= ~RSA_FLAG_BLINDING;
120    rsa->flags |= RSA_FLAG_NO_BLINDING;
121}
122
123int RSA_blinding_on(RSA *rsa, BN_CTX *ctx)
124{
125    int ret = 0;
126
127    if (rsa->blinding != NULL)
128        RSA_blinding_off(rsa);
129
130    rsa->blinding = RSA_setup_blinding(rsa, ctx);
131    if (rsa->blinding == NULL)
132        goto err;
133
134    rsa->flags |= RSA_FLAG_BLINDING;
135    rsa->flags &= ~RSA_FLAG_NO_BLINDING;
136    ret = 1;
137 err:
138    return (ret);
139}
140
141static BIGNUM *rsa_get_public_exp(const BIGNUM *d, const BIGNUM *p,
142                                  const BIGNUM *q, BN_CTX *ctx)
143{
144    BIGNUM *ret = NULL, *r0, *r1, *r2;
145
146    if (d == NULL || p == NULL || q == NULL)
147        return NULL;
148
149    BN_CTX_start(ctx);
150    r0 = BN_CTX_get(ctx);
151    r1 = BN_CTX_get(ctx);
152    r2 = BN_CTX_get(ctx);
153    if (r2 == NULL)
154        goto err;
155
156    if (!BN_sub(r1, p, BN_value_one()))
157        goto err;
158    if (!BN_sub(r2, q, BN_value_one()))
159        goto err;
160    if (!BN_mul(r0, r1, r2, ctx))
161        goto err;
162
163    ret = BN_mod_inverse(NULL, d, r0, ctx);
164 err:
165    BN_CTX_end(ctx);
166    return ret;
167}
168
169BN_BLINDING *RSA_setup_blinding(RSA *rsa, BN_CTX *in_ctx)
170{
171    BIGNUM local_n;
172    BIGNUM *e, *n;
173    BN_CTX *ctx;
174    BN_BLINDING *ret = NULL;
175
176    if (in_ctx == NULL) {
177        if ((ctx = BN_CTX_new()) == NULL)
178            return 0;
179    } else
180        ctx = in_ctx;
181
182    BN_CTX_start(ctx);
183    e = BN_CTX_get(ctx);
184    if (e == NULL) {
185        RSAerr(RSA_F_RSA_SETUP_BLINDING, ERR_R_MALLOC_FAILURE);
186        goto err;
187    }
188
189    if (rsa->e == NULL) {
190        e = rsa_get_public_exp(rsa->d, rsa->p, rsa->q, ctx);
191        if (e == NULL) {
192            RSAerr(RSA_F_RSA_SETUP_BLINDING, RSA_R_NO_PUBLIC_EXPONENT);
193            goto err;
194        }
195    } else
196        e = rsa->e;
197
198    if ((RAND_status() == 0) && rsa->d != NULL && rsa->d->d != NULL) {
199        /*
200         * if PRNG is not properly seeded, resort to secret exponent as
201         * unpredictable seed
202         */
203        RAND_add(rsa->d->d, rsa->d->dmax * sizeof rsa->d->d[0], 0.0);
204    }
205
206    if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
207        /* Set BN_FLG_CONSTTIME flag */
208        n = &local_n;
209        BN_with_flags(n, rsa->n, BN_FLG_CONSTTIME);
210    } else
211        n = rsa->n;
212
213    ret = BN_BLINDING_create_param(NULL, e, n, ctx,
214                                   rsa->meth->bn_mod_exp, rsa->_method_mod_n);
215    if (ret == NULL) {
216        RSAerr(RSA_F_RSA_SETUP_BLINDING, ERR_R_BN_LIB);
217        goto err;
218    }
219    BN_BLINDING_set_thread_id(ret, CRYPTO_thread_id());
220 err:
221    BN_CTX_end(ctx);
222    if (in_ctx == NULL)
223        BN_CTX_free(ctx);
224    if (rsa->e == NULL)
225        BN_free(e);
226
227    return ret;
228}
229