/*

 * Copyright 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

 */

#include <openssl/core.h>

#include <openssl/core_names.h>

#include <openssl/evp.h>

#include <openssl/obj_mac.h>

#include "internal/nelem.h"

#include "crypto/rsa.h"

static int meth2nid(const void *meth,

                    int (*meth_is_a)(const void *meth, const char *name),

                    const OSSL_ITEM *items, size_t items_n)

{

    size_t i;

    if (meth != NULL)

        for (i = 0; i < items_n; i++)

            if (meth_is_a(meth, items[i].ptr))

                return (int)items[i].id;

    return NID_undef;

}

static const char *nid2name(int meth, const OSSL_ITEM *items, size_t items_n)

{

    size_t i;

    for (i = 0; i < items_n; i++)

        if (meth == (int)items[i].id)

            return items[i].ptr;

    return NULL;

}

/*

 * The list of permitted hash functions are taken from 

 * https://tools.ietf.org/html/rfc8017#appendix-A.2.1:

 *

 * OAEP-PSSDigestAlgorithms    ALGORITHM-IDENTIFIER ::= {

 *     { OID id-sha1       PARAMETERS NULL }|

 *     { OID id-sha224     PARAMETERS NULL }|

 *     { OID id-sha256     PARAMETERS NULL }|

 *     { OID id-sha384     PARAMETERS NULL }|

 *     { OID id-sha512     PARAMETERS NULL }|

 *     { OID id-sha512-224 PARAMETERS NULL }|

 *     { OID id-sha512-256 PARAMETERS NULL },

 *     ...  -- Allows for future expansion --

 * }

 */

static const OSSL_ITEM oaeppss_name_nid_map[] = {

    { NID_sha1,         OSSL_DIGEST_NAME_SHA1         },

    { NID_sha224,       OSSL_DIGEST_NAME_SHA2_224     },

    { NID_sha256,       OSSL_DIGEST_NAME_SHA2_256     },

    { NID_sha384,       OSSL_DIGEST_NAME_SHA2_384     },

    { NID_sha512,       OSSL_DIGEST_NAME_SHA2_512     },

    { NID_sha512_224,   OSSL_DIGEST_NAME_SHA2_512_224 },

    { NID_sha512_256,   OSSL_DIGEST_NAME_SHA2_512_256 },

};

static int md_is_a(const void *md, const char *name)

{

    return EVP_MD_is_a(md, name);

}

int ossl_rsa_oaeppss_md2nid(const EVP_MD *md)

{

    return meth2nid(md, md_is_a,

                    oaeppss_name_nid_map, OSSL_NELEM(oaeppss_name_nid_map));

}

const char *ossl_rsa_oaeppss_nid2name(int md)

{

    return nid2name(md, oaeppss_name_nid_map, OSSL_NELEM(oaeppss_name_nid_map));

}

const char *ossl_rsa_mgf_nid2name(int mgf)

{

    if (mgf == NID_mgf1)

        return SN_mgf1;

    return NULL;

}