/*

 * Copyright 1995-2021 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.

 */

#define OPENSSL_SUPPRESS_DEPRECATED

#include <stdio.h>

#include <string.h>

#include <time.h>

#include <openssl/err.h>

#include <openssl/bn.h>

#include "rsa_local.h"

/* X9.31 RSA key derivation and generation */

int RSA_X931_derive_ex(RSA *rsa, BIGNUM *p1, BIGNUM *p2, BIGNUM *q1,

                       BIGNUM *q2, const BIGNUM *Xp1, const BIGNUM *Xp2,

                       const BIGNUM *Xp, const BIGNUM *Xq1, const BIGNUM *Xq2,

                       const BIGNUM *Xq, const BIGNUM *e, BN_GENCB *cb)

{

    BIGNUM *r0 = NULL, *r1 = NULL, *r2 = NULL, *r3 = NULL;

    BN_CTX *ctx = NULL, *ctx2 = NULL;

    int ret = 0;

    if (!rsa)

        goto err;

    ctx = BN_CTX_new();

    if (ctx == NULL)

        goto err;

    BN_CTX_start(ctx);

    r0 = BN_CTX_get(ctx);

    r1 = BN_CTX_get(ctx);

    r2 = BN_CTX_get(ctx);

    r3 = BN_CTX_get(ctx);

    if (r3 == NULL)

        goto err;

    if (!rsa->e) {

        rsa->e = BN_dup(e);

        if (!rsa->e)

            goto err;

    } else {

        e = rsa->e;

    }

    /*

     * If not all parameters present only calculate what we can. This allows

     * test programs to output selective parameters.

     */

    if (Xp && rsa->p == NULL) {

        rsa->p = BN_new();

        if (rsa->p == NULL)

            goto err;

        if (!BN_X931_derive_prime_ex(rsa->p, p1, p2,

                                     Xp, Xp1, Xp2, e, ctx, cb))

            goto err;

    }

    if (Xq && rsa->q == NULL) {

        rsa->q = BN_new();

        if (rsa->q == NULL)

            goto err;

        if (!BN_X931_derive_prime_ex(rsa->q, q1, q2,

                                     Xq, Xq1, Xq2, e, ctx, cb))

            goto err;

    }

    if (rsa->p == NULL || rsa->q == NULL) {

        BN_CTX_end(ctx);

        BN_CTX_free(ctx);

        return 2;

    }

    /*

     * Since both primes are set we can now calculate all remaining

     * components.

     */

    /* calculate n */

    rsa->n = BN_new();

    if (rsa->n == NULL)

        goto err;

    if (!BN_mul(rsa->n, rsa->p, rsa->q, ctx))

        goto err;

    /* calculate d */

    if (!BN_sub(r1, rsa->p, BN_value_one()))

        goto err;               /* p-1 */

    if (!BN_sub(r2, rsa->q, BN_value_one()))

        goto err;               /* q-1 */

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

        goto err;               /* (p-1)(q-1) */

    if (!BN_gcd(r3, r1, r2, ctx))

        goto err;

    if (!BN_div(r0, NULL, r0, r3, ctx))

        goto err;               /* LCM((p-1)(q-1)) */

    ctx2 = BN_CTX_new();

    if (ctx2 == NULL)

        goto err;

    rsa->d = BN_mod_inverse(NULL, rsa->e, r0, ctx2); /* d */

    if (rsa->d == NULL)

        goto err;

    /* calculate d mod (p-1) */

    rsa->dmp1 = BN_new();

    if (rsa->dmp1 == NULL)

        goto err;

    if (!BN_mod(rsa->dmp1, rsa->d, r1, ctx))

        goto err;

    /* calculate d mod (q-1) */

    rsa->dmq1 = BN_new();

    if (rsa->dmq1 == NULL)

        goto err;

    if (!BN_mod(rsa->dmq1, rsa->d, r2, ctx))

        goto err;

    /* calculate inverse of q mod p */

    rsa->iqmp = BN_mod_inverse(NULL, rsa->q, rsa->p, ctx2);

    if (rsa->iqmp == NULL)

        goto err;

    rsa->dirty_cnt++;

    ret = 1;

 err:

    BN_CTX_end(ctx);

    BN_CTX_free(ctx);

    BN_CTX_free(ctx2);

    return ret;

}

int RSA_X931_generate_key_ex(RSA *rsa, int bits, const BIGNUM *e,

                             BN_GENCB *cb)

{

    int ok = 0;

    BIGNUM *Xp = NULL, *Xq = NULL;

    BN_CTX *ctx = NULL;

    ctx = BN_CTX_new();

    if (ctx == NULL)

        goto error;

    BN_CTX_start(ctx);

    Xp = BN_CTX_get(ctx);

    Xq = BN_CTX_get(ctx);

    if (Xq == NULL)

        goto error;

    if (!BN_X931_generate_Xpq(Xp, Xq, bits, ctx))

        goto error;

    rsa->p = BN_new();

    rsa->q = BN_new();

    if (rsa->p == NULL || rsa->q == NULL)

        goto error;

    /* Generate two primes from Xp, Xq */

    if (!BN_X931_generate_prime_ex(rsa->p, NULL, NULL, NULL, NULL, Xp,

                                   e, ctx, cb))

        goto error;

    if (!BN_X931_generate_prime_ex(rsa->q, NULL, NULL, NULL, NULL, Xq,

                                   e, ctx, cb))

        goto error;

    /*

     * Since rsa->p and rsa->q are valid this call will just derive remaining

     * RSA components.

     */

    if (!RSA_X931_derive_ex(rsa, NULL, NULL, NULL, NULL,

                            NULL, NULL, NULL, NULL, NULL, NULL, e, cb))

        goto error;

    rsa->dirty_cnt++;

    ok = 1;

 error:

    BN_CTX_end(ctx);

    BN_CTX_free(ctx);

    if (ok)

        return 1;

    return 0;

}