/*

 * Copyright 2020-2026 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 <string.h>

#include <openssl/core_names.h>

#include <openssl/params.h>

#include <openssl/err.h>

#include <openssl/evp.h>

#ifndef FIPS_MODULE

#include <openssl/x509.h>

#include "crypto/asn1.h"

#endif

#include "internal/sizes.h"

#include "internal/param_build_set.h"

#include "crypto/rsa.h"

#include "crypto/rsa_params.h"

#include "rsa_local.h"

/*

 * The intention with the "backend" source file is to offer backend functions

 * for legacy backends (EVP_PKEY_ASN1_METHOD) and provider implementations

 * alike.

 */

DEFINE_STACK_OF(BIGNUM)

static int collect_numbers(STACK_OF(BIGNUM) *numbers,

    OSSL_PARAM *const params[], size_t num_params)

{

    size_t i;

    if (numbers == NULL)

        return 0;

    for (i = 0; i < num_params; i++) {

        if (params[i] != NULL) {

            BIGNUM *tmp = NULL;

            if (!OSSL_PARAM_get_BN(params[i], &tmp))

                return 0;

            if (sk_BIGNUM_push(numbers, tmp) == 0) {

                BN_clear_free(tmp);

                return 0;

            }

        }

    }

    return 1;

}

int ossl_rsa_fromdata_parsed(RSA *rsa, const RSA_PARAMS *p,

    int include_private)

{

    BIGNUM *n = NULL, *e = NULL, *d = NULL;

    STACK_OF(BIGNUM) *factors = NULL, *exps = NULL, *coeffs = NULL;

    int is_private = 0;

    int derive_from_pq = 0;

    BN_CTX *ctx = NULL;

    if (rsa == NULL || p == NULL)

        return 0;

    if ((p->n == NULL || !OSSL_PARAM_get_BN(p->n, &n))

        || (p->e == NULL || !OSSL_PARAM_get_BN(p->e, &e))) {

        ERR_raise(ERR_LIB_RSA, ERR_R_PASSED_NULL_PARAMETER);

        goto err;

    }

    if (include_private) {

        if ((p->derive != NULL)

            && !OSSL_PARAM_get_int(p->derive, &derive_from_pq))

            goto err;

        if (p->d != NULL && !OSSL_PARAM_get_BN(p->d, &d)) {

            ERR_raise(ERR_LIB_RSA, ERR_R_PASSED_NULL_PARAMETER);

            goto err;

        }

        if (derive_from_pq) {

            ctx = BN_CTX_new_ex(rsa->libctx);

            if (ctx == NULL)

                goto err;

            /* we need at minimum p, q */

            if (p->mp.factors[0] == NULL || p->mp.factors[1] == NULL) {

                ERR_raise(ERR_LIB_RSA, ERR_R_PASSED_NULL_PARAMETER);

                goto err;

            }

        }

    }

    is_private = (d != NULL);

    if (!RSA_set0_key(rsa, n, e, d))

        goto err;

    n = e = d = NULL;

    if (is_private) {

        if (!collect_numbers(factors = sk_BIGNUM_new_null(), p->mp.factors,

                OSSL_NELEM(p->mp.factors))

            || !collect_numbers(exps = sk_BIGNUM_new_null(), p->mp.exps,

                OSSL_NELEM(p->mp.exps))

            || !collect_numbers(coeffs = sk_BIGNUM_new_null(), p->mp.coeffs,

                OSSL_NELEM(p->mp.coeffs)))

            goto err;

        if (derive_from_pq && sk_BIGNUM_num(exps) == 0

            && sk_BIGNUM_num(coeffs) == 0) {

            /*

             * If we want to use crt to derive our exponents/coefficients, we

             * need to have at least 2 factors

             */

            if (sk_BIGNUM_num(factors) < 2) {

                ERR_raise(ERR_LIB_RSA, ERR_R_PASSED_NULL_PARAMETER);

                goto err;

            }

            /*

             * if we have more than two factors, n and d must also have

             * been provided

             */

            if (sk_BIGNUM_num(factors) > 2

                && (p->n == NULL || p->d == NULL)) {

                ERR_raise(ERR_LIB_RSA, ERR_R_PASSED_NULL_PARAMETER);

                goto err;

            }

            /* build our exponents and coefficients here */

            if (sk_BIGNUM_num(factors) == 2) {

                /* for 2 factors we can use the sp800 functions to do this */

                if (!RSA_set0_factors(rsa, sk_BIGNUM_value(factors, 0),

                        sk_BIGNUM_value(factors, 1))) {

                    ERR_raise(ERR_LIB_RSA, ERR_R_INTERNAL_ERROR);

                    goto err;

                }

                /*

                 * once consumed by RSA_set0_factors, pop those off the stack

                 * so we don't free them below

                 */

                sk_BIGNUM_pop(factors);

                sk_BIGNUM_pop(factors);

                /*

                 * Note: Because we only have 2 factors here, there will be no

                 * additional pinfo fields to hold additional factors, and

                 * since we set our key and 2 factors above we can skip

                 * the call to ossl_rsa_set0_all_params

                 */

                if (!ossl_rsa_sp800_56b_derive_params_from_pq(rsa,

                        RSA_bits(rsa),

                        NULL, ctx)) {

                    ERR_raise(ERR_LIB_RSA, ERR_R_INTERNAL_ERROR);

                    goto err;

                }

            } else {

#ifndef FIPS_MODULE

                /*

                 * in the multiprime case we have to generate exps/coeffs here

                 * for each additional prime

                 */

                if (!ossl_rsa_multiprime_derive(rsa, RSA_bits(rsa),

                        sk_BIGNUM_num(factors),

                        rsa->e, factors, exps,

                        coeffs)) {

                    ERR_raise(ERR_LIB_RSA, ERR_R_INTERNAL_ERROR);

                    goto err;

                }

                /*

                 * Now we should have all our factors, exponents and

                 * coefficients

                 */

                if (!ossl_rsa_set0_all_params(rsa, factors, exps, coeffs)) {

                    ERR_raise(ERR_LIB_RSA, ERR_R_INTERNAL_ERROR);

                    goto err;

                }

#else

                /* multiprime case is disallowed in FIPS mode, raise an error */

                ERR_raise(ERR_LIB_RSA, ERR_R_UNSUPPORTED);

                goto err;

#endif

            }

        } else {

            /*

             * It's ok if this private key just has n, e and d

             * but only if we're not using derive_from_pq

             */

            if (sk_BIGNUM_num(factors) != 0

                && !ossl_rsa_set0_all_params(rsa, factors, exps, coeffs))

                goto err;

        }

        /* sanity check to ensure we used everything in our stacks */

        if (sk_BIGNUM_num(factors) != 0

            || sk_BIGNUM_num(exps) != 0

            || sk_BIGNUM_num(coeffs) != 0) {

            ERR_raise_data(ERR_LIB_RSA, ERR_R_INTERNAL_ERROR,

                "There are %d, %d, %d elements left on our factors, exps, coeffs stacks\n",

                sk_BIGNUM_num(factors), sk_BIGNUM_num(exps),

                sk_BIGNUM_num(coeffs));

            goto err;

        }

    }

    if (!ossl_rsa_check_factors(rsa)) {

        ERR_raise_data(ERR_LIB_RSA, RSA_R_INVALID_KEYPAIR,

            "RSA factors/exponents are too big for n-modulus\n");

        goto err;

    }

    sk_BIGNUM_free(factors);

    sk_BIGNUM_free(exps);

    sk_BIGNUM_free(coeffs);

    BN_CTX_free(ctx);

    return 1;

err:

    BN_free(n);

    BN_free(e);

    BN_free(d);

    sk_BIGNUM_pop_free(factors, BN_clear_free);

    sk_BIGNUM_pop_free(exps, BN_clear_free);

    sk_BIGNUM_pop_free(coeffs, BN_clear_free);

    BN_CTX_free(ctx);

    return 0;

}

int ossl_rsa_fromdata(RSA *rsa, const OSSL_PARAM params[],

    int include_private)

{

    RSA_PARAMS p;

    if (!rsa_key_fromdata_decoder(params, &p))

        return 0;

    return ossl_rsa_fromdata_parsed(rsa, &p, include_private);

}

DEFINE_SPECIAL_STACK_OF_CONST(BIGNUM_const, BIGNUM)

static int rsa_set_multi_key_bn(OSSL_PARAM_BLD *bld,

    OSSL_PARAM *const params[], size_t num_params, const char *names[],

    STACK_OF(BIGNUM_const) *numbers)

{

    int i, num_numbers = sk_BIGNUM_const_num(numbers);

    for (i = 0; i < num_numbers && (size_t)i < num_params

        && names[i] != NULL;

        i++) {

        const BIGNUM *bn = sk_BIGNUM_const_value(numbers, i);

        OSSL_PARAM *p = bld == NULL ? params[i] : NULL;

        if (bn != NULL && !ossl_param_build_set_bn(bld, p, names[i], bn))

            return 0;

    }

    return 1;

}

int ossl_rsa_todata_parsed(RSA *rsa, OSSL_PARAM_BLD *bld,

    const RSA_PARAMS *p, int include_private)

{

    int ret = 0;

    const BIGNUM *rsa_d = NULL, *rsa_n = NULL, *rsa_e = NULL;

    STACK_OF(BIGNUM_const) *factors = sk_BIGNUM_const_new_null();

    STACK_OF(BIGNUM_const) *exps = sk_BIGNUM_const_new_null();

    STACK_OF(BIGNUM_const) *coeffs = sk_BIGNUM_const_new_null();

    if (rsa == NULL || (bld == NULL && p == NULL)

        || factors == NULL || exps == NULL || coeffs == NULL)

        goto err;

    RSA_get0_key(rsa, &rsa_n, &rsa_e, &rsa_d);

    ossl_rsa_get0_all_params(rsa, factors, exps, coeffs);

    if (!ossl_param_build_set_bn(bld, p == NULL ? NULL : p->n,

            OSSL_PKEY_PARAM_RSA_N, rsa_n)

        || !ossl_param_build_set_bn(bld, p == NULL ? NULL : p->e,

            OSSL_PKEY_PARAM_RSA_E, rsa_e))

        goto err;

    /* Check private key data integrity */

    if (include_private && rsa_d != NULL) {

        if (!ossl_param_build_set_bn(bld, p == NULL ? NULL : p->d,

                OSSL_PKEY_PARAM_RSA_D,

                rsa_d)

            || !rsa_set_multi_key_bn(bld,

                p == NULL ? NULL : p->mp.factors,

                OSSL_RSA_PARAM_MAX_PRIMES, ossl_rsa_mp_factor_names, factors)

            || !rsa_set_multi_key_bn(bld,

                p == NULL ? NULL : p->mp.exps,

                OSSL_RSA_PARAM_MAX_PRIMES, ossl_rsa_mp_exp_names, exps)

            || !rsa_set_multi_key_bn(bld,

                p == NULL ? NULL : p->mp.coeffs,

                OSSL_RSA_PARAM_MAX_PRIMES - 1,

                ossl_rsa_mp_coeff_names, coeffs))

            goto err;

    }

#if defined(FIPS_MODULE) && !defined(OPENSSL_NO_ACVP_TESTS)

    /* The acvp test results are not meant for export so check for bld == NULL */

    if (bld == NULL)

        ossl_rsa_acvp_test_get_params_parsed(rsa, p);

#endif

    ret = 1;

err:

    sk_BIGNUM_const_free(factors);

    sk_BIGNUM_const_free(exps);

    sk_BIGNUM_const_free(coeffs);

    return ret;

}

int ossl_rsa_todata(RSA *rsa, OSSL_PARAM_BLD *bld, OSSL_PARAM params[],

    int include_private)

{

    RSA_PARAMS p;

    if (params != NULL) {

        if (!rsa_key_todata_decoder(params, &p))

            return 0;

        return ossl_rsa_todata_parsed(rsa, bld, &p, include_private);

    }

    return ossl_rsa_todata_parsed(rsa, bld, NULL, include_private);

}

int ossl_rsa_pss_params_30_todata_parsed(const RSA_PSS_PARAMS_30 *pss,

    OSSL_PARAM_BLD *bld, const RSA_PARAMS *p)

{

    if (bld == NULL && p == NULL)

        return 0;

    if (!ossl_rsa_pss_params_30_is_unrestricted(pss)) {

        int hashalg_nid = ossl_rsa_pss_params_30_hashalg(pss);

        int maskgenalg_nid = ossl_rsa_pss_params_30_maskgenalg(pss);

        int maskgenhashalg_nid = ossl_rsa_pss_params_30_maskgenhashalg(pss);

        int saltlen = ossl_rsa_pss_params_30_saltlen(pss);

        int default_hashalg_nid = ossl_rsa_pss_params_30_hashalg(NULL);

        int default_maskgenalg_nid = ossl_rsa_pss_params_30_maskgenalg(NULL);

        int default_maskgenhashalg_nid = ossl_rsa_pss_params_30_maskgenhashalg(NULL);

        const char *mdname = (hashalg_nid == default_hashalg_nid

                ? NULL

                : ossl_rsa_oaeppss_nid2name(hashalg_nid));

        const char *mgfname = (maskgenalg_nid == default_maskgenalg_nid

                ? NULL

                : ossl_rsa_oaeppss_nid2name(maskgenalg_nid));

        const char *mgf1mdname = (maskgenhashalg_nid == default_maskgenhashalg_nid

                ? NULL

                : ossl_rsa_oaeppss_nid2name(maskgenhashalg_nid));

        const char *key_md = OSSL_PKEY_PARAM_RSA_DIGEST;

        const char *key_mgf = OSSL_PKEY_PARAM_RSA_MASKGENFUNC;

        const char *key_mgf1_md = OSSL_PKEY_PARAM_RSA_MGF1_DIGEST;

        const char *key_saltlen = OSSL_PKEY_PARAM_RSA_PSS_SALTLEN;

        /*

         * To ensure that the key isn't seen as unrestricted by the recipient,

         * we make sure that at least one PSS-related parameter is passed, even

         * if it has a default value; saltlen.

         */

        if ((mdname != NULL

                && !ossl_param_build_set_utf8_string(bld,

                    p == NULL ? NULL : p->digest, key_md, mdname))

            || (mgfname != NULL

                && !ossl_param_build_set_utf8_string(bld,

                    p == NULL ? NULL : p->maskgenfunc, key_mgf, mgfname))

            || (mgf1mdname != NULL

                && !ossl_param_build_set_utf8_string(bld,

                    p == NULL ? NULL : p->mgf1_digest,

                    key_mgf1_md, mgf1mdname))

            || (!ossl_param_build_set_int(bld,

                p == NULL ? NULL : p->pss_saltlen,

                key_saltlen, saltlen)))

            return 0;

    }

    return 1;

}

int ossl_rsa_pss_params_30_todata(const RSA_PSS_PARAMS_30 *pss,

    OSSL_PARAM_BLD *bld, OSSL_PARAM params[])

{

    RSA_PARAMS p;

    if (params != NULL) {

        if (!rsa_pss_todata_decoder(params, &p))

            return 0;

        return ossl_rsa_pss_params_30_todata_parsed(pss, bld, &p);

    }

    return ossl_rsa_pss_params_30_todata_parsed(pss, bld, NULL);

}

int ossl_rsa_pss_params_30_fromdata_parsed(RSA_PSS_PARAMS_30 *pss_params,

    int *defaults_set, const RSA_PARAMS *p, OSSL_LIB_CTX *libctx)

{

    const char *propq = NULL;

    EVP_MD *md = NULL, *mgf1md = NULL;

    int saltlen;

    int ret = 0;

    if (pss_params == NULL || defaults_set == NULL || p == NULL)

        return 0;

    if (p->digest_props != NULL) {

        if (p->digest_props->data_type == OSSL_PARAM_UTF8_STRING)

            propq = p->digest_props->data;

        else if (!OSSL_PARAM_get_utf8_ptr(p->digest_props, &propq))

            return 0;

    }

    /*

     * If we get any of the parameters, we know we have at least some

     * restrictions, so we start by setting default values, and let each

     * parameter override their specific restriction data.

     */

    if (!*defaults_set

        && (p->digest != NULL || p->maskgenfunc != NULL || p->mgf1_digest != NULL

            || p->pss_saltlen != NULL)) {

        if (!ossl_rsa_pss_params_30_set_defaults(pss_params))

            return 0;

        *defaults_set = 1;

    }

    if (p->maskgenfunc != NULL) {

        int default_maskgenalg_nid = ossl_rsa_pss_params_30_maskgenalg(NULL);

        const char *mgfname = NULL;

        if (p->maskgenfunc->data_type == OSSL_PARAM_UTF8_STRING)

            mgfname = p->maskgenfunc->data;

        else if (!OSSL_PARAM_get_utf8_ptr(p->maskgenfunc, &mgfname))

            return 0;

        if (mgfname == NULL

            || OPENSSL_strcasecmp(mgfname,

                   ossl_rsa_mgf_nid2name(default_maskgenalg_nid))

                != 0)

            return 0;

    }

    /*

     * We're only interested in the NIDs that correspond to the MDs, so the

     * exact propquery is unimportant in the EVP_MD_fetch() calls below.

     */

    if (p->digest != NULL) {

        const char *mdname = NULL;

        if (p->digest->data_type == OSSL_PARAM_UTF8_STRING)

            mdname = p->digest->data;

        else if (!OSSL_PARAM_get_utf8_ptr(p->digest, &mdname))

            goto err;

        if ((md = EVP_MD_fetch(libctx, mdname, propq)) == NULL

            || !ossl_rsa_pss_params_30_set_hashalg(pss_params,

                ossl_rsa_oaeppss_md2nid(md)))

            goto err;

    }

    if (p->mgf1_digest != NULL) {

        const char *mgf1mdname = NULL;

        if (p->mgf1_digest->data_type == OSSL_PARAM_UTF8_STRING)

            mgf1mdname = p->mgf1_digest->data;

        else if (!OSSL_PARAM_get_utf8_ptr(p->mgf1_digest, &mgf1mdname))

            goto err;

        if ((mgf1md = EVP_MD_fetch(libctx, mgf1mdname, propq)) == NULL

            || !ossl_rsa_pss_params_30_set_maskgenhashalg(

                pss_params, ossl_rsa_oaeppss_md2nid(mgf1md)))

            goto err;

    }

    if (p->pss_saltlen != NULL) {

        if (!OSSL_PARAM_get_int(p->pss_saltlen, &saltlen)

            || !ossl_rsa_pss_params_30_set_saltlen(pss_params, saltlen))

            goto err;

    }

    ret = 1;

err:

    EVP_MD_free(md);

    EVP_MD_free(mgf1md);

    return ret;

}

int ossl_rsa_pss_params_30_fromdata(RSA_PSS_PARAMS_30 *pss_params,

    int *defaults_set, const OSSL_PARAM params[], OSSL_LIB_CTX *libctx)

{

    RSA_PARAMS p;

    if (!rsa_pss_fromdata_decoder(params, &p))

        return 0;

    return ossl_rsa_pss_params_30_fromdata_parsed(pss_params, defaults_set,

        &p, libctx);

}

int ossl_rsa_is_foreign(const RSA *rsa)

{

#ifndef FIPS_MODULE

    if (RSA_get_method(rsa) != RSA_PKCS1_OpenSSL())

        return 1;

#endif

    return 0;

}

static ossl_inline int rsa_bn_dup_check(BIGNUM **out, const BIGNUM *f)

{

    if (f != NULL && (*out = BN_dup(f)) == NULL)

        return 0;

    return 1;

}

RSA *ossl_rsa_dup(const RSA *rsa, int selection)

{

    RSA *dupkey = NULL;

#ifndef FIPS_MODULE

    int pnum, i;

#endif

    /* Do not try to duplicate foreign RSA keys */

    if (ossl_rsa_is_foreign(rsa))

        return NULL;

    if ((dupkey = ossl_rsa_new_with_ctx(rsa->libctx)) == NULL)

        return NULL;

    /* public key */

    if ((selection & OSSL_KEYMGMT_SELECT_KEYPAIR) != 0) {

        if (!rsa_bn_dup_check(&dupkey->n, rsa->n))

            goto err;

        if (!rsa_bn_dup_check(&dupkey->e, rsa->e))

            goto err;

    }

    if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0) {

        /* private key */

        if (!rsa_bn_dup_check(&dupkey->d, rsa->d))

            goto err;

        /* factors and crt params */

        if (!rsa_bn_dup_check(&dupkey->p, rsa->p))

            goto err;

        if (!rsa_bn_dup_check(&dupkey->q, rsa->q))

            goto err;

        if (!rsa_bn_dup_check(&dupkey->dmp1, rsa->dmp1))

            goto err;

        if (!rsa_bn_dup_check(&dupkey->dmq1, rsa->dmq1))

            goto err;

        if (!rsa_bn_dup_check(&dupkey->iqmp, rsa->iqmp))

            goto err;

    }

    dupkey->version = rsa->version;

    dupkey->flags = rsa->flags;

    /* we always copy the PSS parameters regardless of selection */

    dupkey->pss_params = rsa->pss_params;

#ifndef FIPS_MODULE

    /* multiprime */

    if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0

        && (pnum = sk_RSA_PRIME_INFO_num(rsa->prime_infos)) > 0) {

        dupkey->prime_infos = sk_RSA_PRIME_INFO_new_reserve(NULL, pnum);

        if (dupkey->prime_infos == NULL)

            goto err;

        for (i = 0; i < pnum; i++) {

            const RSA_PRIME_INFO *pinfo = NULL;

            RSA_PRIME_INFO *duppinfo = NULL;

            if ((duppinfo = OPENSSL_zalloc(sizeof(*duppinfo))) == NULL)

                goto err;

            /* push first so cleanup in error case works */

            (void)sk_RSA_PRIME_INFO_push(dupkey->prime_infos, duppinfo);

            pinfo = sk_RSA_PRIME_INFO_value(rsa->prime_infos, i);

            if (!rsa_bn_dup_check(&duppinfo->r, pinfo->r))

                goto err;

            if (!rsa_bn_dup_check(&duppinfo->d, pinfo->d))

                goto err;

            if (!rsa_bn_dup_check(&duppinfo->t, pinfo->t))

                goto err;

        }

        if (!ossl_rsa_multip_calc_product(dupkey))

            goto err;

    }

    if (rsa->pss != NULL) {

        if ((dupkey->pss = RSA_PSS_PARAMS_dup(rsa->pss)) == NULL)

            goto err;

        if (rsa->pss->maskGenAlgorithm != NULL

            && dupkey->pss->maskGenAlgorithm == NULL) {

            dupkey->pss->maskHash = ossl_x509_algor_mgf1_decode(rsa->pss->maskGenAlgorithm);

            if (dupkey->pss->maskHash == NULL)

                goto err;

        }

    }

    if (!CRYPTO_dup_ex_data(CRYPTO_EX_INDEX_RSA,

            &dupkey->ex_data, &rsa->ex_data))

        goto err;

#endif

    return dupkey;

err:

    RSA_free(dupkey);

    return NULL;

}

#ifndef FIPS_MODULE

RSA_PSS_PARAMS *ossl_rsa_pss_decode(const X509_ALGOR *alg)

{

    RSA_PSS_PARAMS *pss;

    pss = ASN1_TYPE_unpack_sequence(ASN1_ITEM_rptr(RSA_PSS_PARAMS),

        alg->parameter);

    if (pss == NULL)

        return NULL;

    if (pss->maskGenAlgorithm != NULL) {

        pss->maskHash = ossl_x509_algor_mgf1_decode(pss->maskGenAlgorithm);

        if (pss->maskHash == NULL) {

            RSA_PSS_PARAMS_free(pss);

            return NULL;

        }

    }

    return pss;

}

static int ossl_rsa_sync_to_pss_params_30(RSA *rsa)

{

    const RSA_PSS_PARAMS *legacy_pss = NULL;

    RSA_PSS_PARAMS_30 *pss = NULL;

    if (rsa != NULL

        && (legacy_pss = RSA_get0_pss_params(rsa)) != NULL

        && (pss = ossl_rsa_get0_pss_params_30(rsa)) != NULL) {

        const EVP_MD *md = NULL, *mgf1md = NULL;

        int md_nid, mgf1md_nid, saltlen, trailerField;

        RSA_PSS_PARAMS_30 pss_params;

        /*

         * We don't care about the validity of the fields here, we just

         * want to synchronise values.  Verifying here makes it impossible

         * to even read a key with invalid values, making it hard to test

         * a bad situation.

         *

         * Other routines use ossl_rsa_pss_get_param(), so the values will

         * be checked, eventually.

         */

        if (!ossl_rsa_pss_get_param_unverified(legacy_pss, &md, &mgf1md,

                &saltlen, &trailerField))

            return 0;

        md_nid = EVP_MD_get_type(md);

        mgf1md_nid = EVP_MD_get_type(mgf1md);

        if (!ossl_rsa_pss_params_30_set_defaults(&pss_params)

            || !ossl_rsa_pss_params_30_set_hashalg(&pss_params, md_nid)

            || !ossl_rsa_pss_params_30_set_maskgenhashalg(&pss_params,

                mgf1md_nid)

            || !ossl_rsa_pss_params_30_set_saltlen(&pss_params, saltlen)

            || !ossl_rsa_pss_params_30_set_trailerfield(&pss_params,

                trailerField))

            return 0;

        *pss = pss_params;

    }

    return 1;

}

int ossl_rsa_pss_get_param_unverified(const RSA_PSS_PARAMS *pss,

    const EVP_MD **pmd, const EVP_MD **pmgf1md,

    int *psaltlen, int *ptrailerField)

{

    RSA_PSS_PARAMS_30 pss_params;

    /* Get the defaults from the ONE place */

    (void)ossl_rsa_pss_params_30_set_defaults(&pss_params);

    if (pss == NULL)

        return 0;

    *pmd = ossl_x509_algor_get_md(pss->hashAlgorithm);

    if (*pmd == NULL)

        return 0;

    *pmgf1md = ossl_x509_algor_get_md(pss->maskHash);

    if (*pmgf1md == NULL)

        return 0;

    if (pss->saltLength)

        *psaltlen = ASN1_INTEGER_get(pss->saltLength);

    else

        *psaltlen = ossl_rsa_pss_params_30_saltlen(&pss_params);

    if (pss->trailerField)

        *ptrailerField = ASN1_INTEGER_get(pss->trailerField);

    else

        *ptrailerField = ossl_rsa_pss_params_30_trailerfield(&pss_params);

    return 1;

}

int ossl_rsa_param_decode(RSA *rsa, const X509_ALGOR *alg)

{

    RSA_PSS_PARAMS *pss;

    const ASN1_OBJECT *algoid;

    const void *algp;

    int algptype;

    X509_ALGOR_get0(&algoid, &algptype, &algp, alg);

    if (OBJ_obj2nid(algoid) != EVP_PKEY_RSA_PSS)

        return 1;

    if (algptype == V_ASN1_UNDEF)

        return 1;

    if (algptype != V_ASN1_SEQUENCE) {

        ERR_raise(ERR_LIB_RSA, RSA_R_INVALID_PSS_PARAMETERS);

        return 0;

    }

    if ((pss = ossl_rsa_pss_decode(alg)) == NULL

        || !ossl_rsa_set0_pss_params(rsa, pss)) {

        RSA_PSS_PARAMS_free(pss);

        return 0;

    }

    if (!ossl_rsa_sync_to_pss_params_30(rsa))

        return 0;

    return 1;

}

RSA *ossl_rsa_key_from_pkcs8(const PKCS8_PRIV_KEY_INFO *p8inf,

    OSSL_LIB_CTX *libctx, const char *propq)

{

    const unsigned char *p;

    RSA *rsa;

    int pklen;

    const X509_ALGOR *alg;

    if (!PKCS8_pkey_get0(NULL, &p, &pklen, &alg, p8inf))

        return 0;

    rsa = d2i_RSAPrivateKey(NULL, &p, pklen);

    if (rsa == NULL) {

        ERR_raise(ERR_LIB_RSA, ERR_R_RSA_LIB);

        return NULL;

    }

    if (!ossl_rsa_param_decode(rsa, alg)) {

        RSA_free(rsa);

        return NULL;

    }

    RSA_clear_flags(rsa, RSA_FLAG_TYPE_MASK);

    switch (OBJ_obj2nid(alg->algorithm)) {

    case EVP_PKEY_RSA:

        RSA_set_flags(rsa, RSA_FLAG_TYPE_RSA);

        break;

    case EVP_PKEY_RSA_PSS:

        RSA_set_flags(rsa, RSA_FLAG_TYPE_RSASSAPSS);

        break;

    default:

        /* Leave the type bits zero */

        break;

    }

    return rsa;

}

#endif