crypto/rsa/rsa_crpt.c

   1 /*
   2  * Copyright 1995-2017 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the OpenSSL license (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 <openssl/lhash.h>
  14 #include "internal/bn_int.h"
  15 #include <openssl/rand.h>
  16 #include "rsa_locl.h"
  17
  18 int RSA_bits(const RSA *r)
  19 {
  20     return BN_num_bits(r->n);
  21 }
  22
  23 int RSA_size(const RSA *r)
  24 {
  25     return BN_num_bytes(r->n);
  26 }
  27
  28 int RSA_public_encrypt(int flen, const unsigned char *from, unsigned char *to,
  29                        RSA *rsa, int padding)
  30 {
  31     return rsa->meth->rsa_pub_enc(flen, from, to, rsa, padding);
  32 }
  33
  34 int RSA_private_encrypt(int flen, const unsigned char *from,
  35                         unsigned char *to, RSA *rsa, int padding)
  36 {
  37     return rsa->meth->rsa_priv_enc(flen, from, to, rsa, padding);
  38 }
  39
  40 int RSA_private_decrypt(int flen, const unsigned char *from,
  41                         unsigned char *to, RSA *rsa, int padding)
  42 {
  43     return rsa->meth->rsa_priv_dec(flen, from, to, rsa, padding);
  44 }
  45
  46 int RSA_public_decrypt(int flen, const unsigned char *from, unsigned char *to,
  47                        RSA *rsa, int padding)
  48 {
  49     return rsa->meth->rsa_pub_dec(flen, from, to, rsa, padding);
  50 }
  51
  52 int RSA_flags(const RSA *r)
  53 {
  54     return r == NULL ? 0 : r->meth->flags;
  55 }
  56
  57 void RSA_blinding_off(RSA *rsa)
  58 {
  59     BN_BLINDING_free(rsa->blinding);
  60     rsa->blinding = NULL;
  61     rsa->flags &= ~RSA_FLAG_BLINDING;
  62     rsa->flags |= RSA_FLAG_NO_BLINDING;
  63 }
  64
  65 int RSA_blinding_on(RSA *rsa, BN_CTX *ctx)
  66 {
  67     int ret = 0;
  68
  69     if (rsa->blinding != NULL)
  70         RSA_blinding_off(rsa);
  71
  72     rsa->blinding = RSA_setup_blinding(rsa, ctx);
  73     if (rsa->blinding == NULL)
  74         goto err;
  75
  76     rsa->flags |= RSA_FLAG_BLINDING;
  77     rsa->flags &= ~RSA_FLAG_NO_BLINDING;
  78     ret = 1;
  79  err:
  80     return ret;
  81 }
  82
  83 static BIGNUM *rsa_get_public_exp(const BIGNUM *d, const BIGNUM *p,
  84                                   const BIGNUM *q, BN_CTX *ctx)
  85 {
  86     BIGNUM *ret = NULL, *r0, *r1, *r2;
  87
  88     if (d == NULL || p == NULL || q == NULL)
  89         return NULL;
  90
  91     BN_CTX_start(ctx);
  92     r0 = BN_CTX_get(ctx);
  93     r1 = BN_CTX_get(ctx);
  94     r2 = BN_CTX_get(ctx);
  95     if (r2 == NULL)
  96         goto err;
  97
  98     if (!BN_sub(r1, p, BN_value_one()))
  99         goto err;
 100     if (!BN_sub(r2, q, BN_value_one()))
 101         goto err;
 102     if (!BN_mul(r0, r1, r2, ctx))
 103         goto err;
 104
 105     ret = BN_mod_inverse(NULL, d, r0, ctx);
 106  err:
 107     BN_CTX_end(ctx);
 108     return ret;
 109 }
 110
 111 BN_BLINDING *RSA_setup_blinding(RSA *rsa, BN_CTX *in_ctx)
 112 {
 113     BIGNUM *e;
 114     BN_CTX *ctx;
 115     BN_BLINDING *ret = NULL;
 116
 117     if (in_ctx == NULL) {
 118         if ((ctx = BN_CTX_new()) == NULL)
 119             return 0;
 120     } else
 121         ctx = in_ctx;
 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         BIGNUM *n = BN_new();
 141
 142         if (n == NULL) {
 143             RSAerr(RSA_F_RSA_SETUP_BLINDING, ERR_R_MALLOC_FAILURE);
 144             goto err;
 145         }
 146         BN_with_flags(n, rsa->n, BN_FLG_CONSTTIME);
 147
 148         ret = BN_BLINDING_create_param(NULL, e, n, ctx, rsa->meth->bn_mod_exp,
 149                                        rsa->_method_mod_n);
 150         /* We MUST free n before any further use of rsa->n */
 151         BN_free(n);
 152     }
 153     if (ret == NULL) {
 154         RSAerr(RSA_F_RSA_SETUP_BLINDING, ERR_R_BN_LIB);
 155         goto err;
 156     }
 157
 158     BN_BLINDING_set_current_thread(ret);
 159
 160  err:
 161     BN_CTX_end(ctx);
 162     if (ctx != in_ctx)
 163         BN_CTX_free(ctx);
 164     if (e != rsa->e)
 165         BN_free(e);
 166
 167     return ret;
 168 }