/*

 * Copyright 1995-2020 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the Apache License 2.0 (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

/*

 * RSA low level APIs are deprecated for public use, but still ok for

 * internal use.

 */

#include "internal/deprecated.h"

#include <stdio.h>

#include <openssl/crypto.h>

#include "internal/cryptlib.h"

#include "crypto/bn.h"

#include <openssl/rand.h>

#include "rsa_local.h"

int RSA_bits(const RSA *r)

{

    return BN_num_bits(r->n);

}

int RSA_size(const RSA *r)

{

    return BN_num_bytes(r->n);

}

int RSA_public_encrypt(int flen, const unsigned char *from, unsigned char *to,

                       RSA *rsa, int padding)

{

    return rsa->meth->rsa_pub_enc(flen, from, to, rsa, padding);

}

int RSA_private_encrypt(int flen, const unsigned char *from,

                        unsigned char *to, RSA *rsa, int padding)

{

    return rsa->meth->rsa_priv_enc(flen, from, to, rsa, padding);

}

int RSA_private_decrypt(int flen, const unsigned char *from,

                        unsigned char *to, RSA *rsa, int padding)

{

    return rsa->meth->rsa_priv_dec(flen, from, to, rsa, padding);

}

int RSA_public_decrypt(int flen, const unsigned char *from, unsigned char *to,

                       RSA *rsa, int padding)

{

    return rsa->meth->rsa_pub_dec(flen, from, to, rsa, padding);

}

int RSA_flags(const RSA *r)

{

    return r == NULL ? 0 : r->meth->flags;

}

void RSA_blinding_off(RSA *rsa)

{

    BN_BLINDING_free(rsa->blinding);

    rsa->blinding = NULL;

    rsa->flags &= ~RSA_FLAG_BLINDING;

    rsa->flags |= RSA_FLAG_NO_BLINDING;

}

int RSA_blinding_on(RSA *rsa, BN_CTX *ctx)

{

    int ret = 0;

    if (rsa->blinding != NULL)

        RSA_blinding_off(rsa);

    rsa->blinding = RSA_setup_blinding(rsa, ctx);

    if (rsa->blinding == NULL)

        goto err;

    rsa->flags |= RSA_FLAG_BLINDING;

    rsa->flags &= ~RSA_FLAG_NO_BLINDING;

    ret = 1;

 err:

    return ret;

}

static BIGNUM *rsa_get_public_exp(const BIGNUM *d, const BIGNUM *p,

                                  const BIGNUM *q, BN_CTX *ctx)

{

    BIGNUM *ret = NULL, *r0, *r1, *r2;

    if (d == NULL || p == NULL || q == NULL)

        return NULL;

    BN_CTX_start(ctx);

    r0 = BN_CTX_get(ctx);

    r1 = BN_CTX_get(ctx);

    r2 = BN_CTX_get(ctx);

    if (r2 == NULL)

        goto err;

    if (!BN_sub(r1, p, BN_value_one()))

        goto err;

    if (!BN_sub(r2, q, BN_value_one()))

        goto err;

    if (!BN_mul(r0, r1, r2, ctx))

        goto err;

    ret = BN_mod_inverse(NULL, d, r0, ctx);

 err:

    BN_CTX_end(ctx);

    return ret;

}

BN_BLINDING *RSA_setup_blinding(RSA *rsa, BN_CTX *in_ctx)

{

    BIGNUM *e;

    BN_CTX *ctx;

    BN_BLINDING *ret = NULL;

    if (in_ctx == NULL) {

        if ((ctx = BN_CTX_new_ex(rsa->libctx)) == NULL)

            return 0;

    } else {

        ctx = in_ctx;

    }

    BN_CTX_start(ctx);

    e = BN_CTX_get(ctx);

    if (e == NULL) {

        ERR_raise(ERR_LIB_RSA, ERR_R_BN_LIB);

        goto err;

    }

    if (rsa->e == NULL) {

        e = rsa_get_public_exp(rsa->d, rsa->p, rsa->q, ctx);

        if (e == NULL) {

            ERR_raise(ERR_LIB_RSA, RSA_R_NO_PUBLIC_EXPONENT);

            goto err;

        }

    } else {

        e = rsa->e;

    }

    {

        BIGNUM *n = BN_new();

        if (n == NULL) {

            ERR_raise(ERR_LIB_RSA, ERR_R_BN_LIB);

            goto err;

        }

        BN_with_flags(n, rsa->n, BN_FLG_CONSTTIME);

        ret = BN_BLINDING_create_param(NULL, e, n, ctx, rsa->meth->bn_mod_exp,

                                       rsa->_method_mod_n);

        /* We MUST free n before any further use of rsa->n */

        BN_free(n);

    }

    if (ret == NULL) {

        ERR_raise(ERR_LIB_RSA, ERR_R_BN_LIB);

        goto err;

    }

    BN_BLINDING_set_current_thread(ret);

 err:

    BN_CTX_end(ctx);

    if (ctx != in_ctx)

        BN_CTX_free(ctx);

    if (e != rsa->e)

        BN_free(e);

    return ret;

}