1/*
2 * Copyright 1995-2017 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10#include <stdio.h>
11#include <openssl/crypto.h>
12#include "internal/cryptlib.h"
13#include "crypto/bn.h"
14#include <openssl/rand.h>
15#include "rsa_local.h"
16
17int RSA_bits(const RSA *r)
18{
19 return BN_num_bits(r->n);
20}
21
22int RSA_size(const RSA *r)
23{
24 return BN_num_bytes(r->n);
25}
26
27int RSA_public_encrypt(int flen, const unsigned char *from, unsigned char *to,
28 RSA *rsa, int padding)
29{
30 return rsa->meth->rsa_pub_enc(flen, from, to, rsa, padding);
31}
32
33int RSA_private_encrypt(int flen, const unsigned char *from,
34 unsigned char *to, RSA *rsa, int padding)
35{
36 return rsa->meth->rsa_priv_enc(flen, from, to, rsa, padding);
37}
38
39int RSA_private_decrypt(int flen, const unsigned char *from,
40 unsigned char *to, RSA *rsa, int padding)
41{
42 return rsa->meth->rsa_priv_dec(flen, from, to, rsa, padding);
43}
44
45int RSA_public_decrypt(int flen, const unsigned char *from, unsigned char *to,
46 RSA *rsa, int padding)
47{
48 return rsa->meth->rsa_pub_dec(flen, from, to, rsa, padding);
49}
50
51int RSA_flags(const RSA *r)
52{
53 return r == NULL ? 0 : r->meth->flags;
54}
55
56void RSA_blinding_off(RSA *rsa)
57{
58 BN_BLINDING_free(rsa->blinding);
59 rsa->blinding = NULL;
60 rsa->flags &= ~RSA_FLAG_BLINDING;
61 rsa->flags |= RSA_FLAG_NO_BLINDING;
62}
63
64int RSA_blinding_on(RSA *rsa, BN_CTX *ctx)
65{
66 int ret = 0;
67
68 if (rsa->blinding != NULL)
69 RSA_blinding_off(rsa);
70
71 rsa->blinding = RSA_setup_blinding(rsa, ctx);
72 if (rsa->blinding == NULL)
73 goto err;
74
75 rsa->flags |= RSA_FLAG_BLINDING;
76 rsa->flags &= ~RSA_FLAG_NO_BLINDING;
77 ret = 1;
78 err:
79 return ret;
80}
81
82static BIGNUM *rsa_get_public_exp(const BIGNUM *d, const BIGNUM *p,
83 const BIGNUM *q, BN_CTX *ctx)
84{
85 BIGNUM *ret = NULL, *r0, *r1, *r2;
86
87 if (d == NULL || p == NULL || q == NULL)
88 return NULL;
89
90 BN_CTX_start(ctx);
91 r0 = BN_CTX_get(ctx);
92 r1 = BN_CTX_get(ctx);
93 r2 = BN_CTX_get(ctx);
94 if (r2 == NULL)
95 goto err;
96
97 if (!BN_sub(r1, p, BN_value_one()))
98 goto err;
99 if (!BN_sub(r2, q, BN_value_one()))
100 goto err;
101 if (!BN_mul(r0, r1, r2, ctx))
102 goto err;
103
104 ret = BN_mod_inverse(NULL, d, r0, ctx);
105 err:
106 BN_CTX_end(ctx);
107 return ret;
108}
109
110BN_BLINDING *RSA_setup_blinding(RSA *rsa, BN_CTX *in_ctx)
111{
112 BIGNUM *e;
113 BN_CTX *ctx;
114 BN_BLINDING *ret = NULL;
115
116 if (in_ctx == NULL) {
117 if ((ctx = BN_CTX_new()) == NULL)
118 return 0;
119 } else {
120 ctx = in_ctx;
121 }
122
123 BN_CTX_start(ctx);
124 e = BN_CTX_get(ctx);
125 if (e == NULL) {
126 RSAerr(RSA_F_RSA_SETUP_BLINDING, ERR_R_MALLOC_FAILURE);
127 goto err;
128 }
129
130 if (rsa->e == NULL) {
131 e = rsa_get_public_exp(rsa->d, rsa->p, rsa->q, ctx);
132 if (e == NULL) {
133 RSAerr(RSA_F_RSA_SETUP_BLINDING, RSA_R_NO_PUBLIC_EXPONENT);
134 goto err;
135 }
136 } else {
137 e = rsa->e;
138 }
139
140 {
141 BIGNUM *n = BN_new();
142
143 if (n == NULL) {
144 RSAerr(RSA_F_RSA_SETUP_BLINDING, ERR_R_MALLOC_FAILURE);
145 goto err;
146 }
147 BN_with_flags(n, rsa->n, BN_FLG_CONSTTIME);
148
149 ret = BN_BLINDING_create_param(NULL, e, n, ctx, rsa->meth->bn_mod_exp,
150 rsa->_method_mod_n);
151 /* We MUST free n before any further use of rsa->n */
152 BN_free(n);
153 }
154 if (ret == NULL) {
155 RSAerr(RSA_F_RSA_SETUP_BLINDING, ERR_R_BN_LIB);
156 goto err;
157 }
158
159 BN_BLINDING_set_current_thread(ret);
160
161 err:
162 BN_CTX_end(ctx);
163 if (ctx != in_ctx)
164 BN_CTX_free(ctx);
165 if (e != rsa->e)
166 BN_free(e);
167
168 return ret;
169}
170