1/*
2 * Copyright 1995-2020 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/*
11 * RSA low level APIs are deprecated for public use, but still ok for
12 * internal use.
13 */
14#include "internal/deprecated.h"
15
16#include <stdio.h>
17#include <openssl/crypto.h>
18#include "internal/cryptlib.h"
19#include "crypto/bn.h"
20#include <openssl/rand.h>
21#include "rsa_local.h"
22
23int RSA_bits(const RSA *r)
24{
25    return BN_num_bits(r->n);
26}
27
28int RSA_size(const RSA *r)
29{
30    return BN_num_bytes(r->n);
31}
32
33int RSA_public_encrypt(int flen, const unsigned char *from, unsigned char *to,
34                       RSA *rsa, int padding)
35{
36    return rsa->meth->rsa_pub_enc(flen, from, to, rsa, padding);
37}
38
39int RSA_private_encrypt(int flen, const unsigned char *from,
40                        unsigned char *to, RSA *rsa, int padding)
41{
42    return rsa->meth->rsa_priv_enc(flen, from, to, rsa, padding);
43}
44
45int RSA_private_decrypt(int flen, const unsigned char *from,
46                        unsigned char *to, RSA *rsa, int padding)
47{
48    return rsa->meth->rsa_priv_dec(flen, from, to, rsa, padding);
49}
50
51int RSA_public_decrypt(int flen, const unsigned char *from, unsigned char *to,
52                       RSA *rsa, int padding)
53{
54    return rsa->meth->rsa_pub_dec(flen, from, to, rsa, padding);
55}
56
57int RSA_flags(const RSA *r)
58{
59    return r == NULL ? 0 : r->meth->flags;
60}
61
62void RSA_blinding_off(RSA *rsa)
63{
64    BN_BLINDING_free(rsa->blinding);
65    rsa->blinding = NULL;
66    rsa->flags &= ~RSA_FLAG_BLINDING;
67    rsa->flags |= RSA_FLAG_NO_BLINDING;
68}
69
70int RSA_blinding_on(RSA *rsa, BN_CTX *ctx)
71{
72    int ret = 0;
73
74    if (rsa->blinding != NULL)
75        RSA_blinding_off(rsa);
76
77    rsa->blinding = RSA_setup_blinding(rsa, ctx);
78    if (rsa->blinding == NULL)
79        goto err;
80
81    rsa->flags |= RSA_FLAG_BLINDING;
82    rsa->flags &= ~RSA_FLAG_NO_BLINDING;
83    ret = 1;
84 err:
85    return ret;
86}
87
88static BIGNUM *rsa_get_public_exp(const BIGNUM *d, const BIGNUM *p,
89                                  const BIGNUM *q, BN_CTX *ctx)
90{
91    BIGNUM *ret = NULL, *r0, *r1, *r2;
92
93    if (d == NULL || p == NULL || q == NULL)
94        return NULL;
95
96    BN_CTX_start(ctx);
97    r0 = BN_CTX_get(ctx);
98    r1 = BN_CTX_get(ctx);
99    r2 = BN_CTX_get(ctx);
100    if (r2 == NULL)
101        goto err;
102
103    if (!BN_sub(r1, p, BN_value_one()))
104        goto err;
105    if (!BN_sub(r2, q, BN_value_one()))
106        goto err;
107    if (!BN_mul(r0, r1, r2, ctx))
108        goto err;
109
110    ret = BN_mod_inverse(NULL, d, r0, ctx);
111 err:
112    BN_CTX_end(ctx);
113    return ret;
114}
115
116BN_BLINDING *RSA_setup_blinding(RSA *rsa, BN_CTX *in_ctx)
117{
118    BIGNUM *e;
119    BN_CTX *ctx;
120    BN_BLINDING *ret = NULL;
121
122    if (in_ctx == NULL) {
123        if ((ctx = BN_CTX_new_ex(rsa->libctx)) == NULL)
124            return 0;
125    } else {
126        ctx = in_ctx;
127    }
128
129    BN_CTX_start(ctx);
130    e = BN_CTX_get(ctx);
131    if (e == NULL) {
132        ERR_raise(ERR_LIB_RSA, ERR_R_MALLOC_FAILURE);
133        goto err;
134    }
135
136    if (rsa->e == NULL) {
137        e = rsa_get_public_exp(rsa->d, rsa->p, rsa->q, ctx);
138        if (e == NULL) {
139            ERR_raise(ERR_LIB_RSA, RSA_R_NO_PUBLIC_EXPONENT);
140            goto err;
141        }
142    } else {
143        e = rsa->e;
144    }
145
146    {
147        BIGNUM *n = BN_new();
148
149        if (n == NULL) {
150            ERR_raise(ERR_LIB_RSA, ERR_R_MALLOC_FAILURE);
151            goto err;
152        }
153        BN_with_flags(n, rsa->n, BN_FLG_CONSTTIME);
154
155        ret = BN_BLINDING_create_param(NULL, e, n, ctx, rsa->meth->bn_mod_exp,
156                                       rsa->_method_mod_n);
157        /* We MUST free n before any further use of rsa->n */
158        BN_free(n);
159    }
160    if (ret == NULL) {
161        ERR_raise(ERR_LIB_RSA, ERR_R_BN_LIB);
162        goto err;
163    }
164
165    BN_BLINDING_set_current_thread(ret);
166
167 err:
168    BN_CTX_end(ctx);
169    if (ctx != in_ctx)
170        BN_CTX_free(ctx);
171    if (e != rsa->e)
172        BN_free(e);
173
174    return ret;
175}
176