/*

 * Copyright 2020-2022 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 "internal/ffc.h"

#include "internal/nelem.h"

#include "crypto/bn_dh.h"

#ifndef OPENSSL_NO_DH

# define FFDHE(sz, keylength) {                                             \

        SN_ffdhe##sz, NID_ffdhe##sz,                                        \

        sz,                                                                 \

        keylength,                                                          \

        &ossl_bignum_ffdhe##sz##_p, &ossl_bignum_ffdhe##sz##_q,             \

        &ossl_bignum_const_2,                                               \

    }

# define MODP(sz, keylength)  {                                             \

        SN_modp_##sz, NID_modp_##sz,                                        \

        sz,                                                                 \

        keylength,                                                          \

        &ossl_bignum_modp_##sz##_p, &ossl_bignum_modp_##sz##_q,             \

        &ossl_bignum_const_2                                                \

    }

# define RFC5114(name, uid, sz, tag) {                                      \

        name, uid,                                                          \

        sz,                                                                 \

        0,                                                                  \

        &ossl_bignum_dh##tag##_p, &ossl_bignum_dh##tag##_q,                 \

        &ossl_bignum_dh##tag##_g                                            \

    }

#else

# define FFDHE(sz, keylength)           { SN_ffdhe##sz, NID_ffdhe##sz }

# define MODP(sz, keylength)            { SN_modp_##sz, NID_modp_##sz }

# define RFC5114(name, uid, sz, tag)    { name, uid }

#endif

struct dh_named_group_st {

    const char *name;

    int uid;

#ifndef OPENSSL_NO_DH

    int32_t nbits;

    int keylength;

    const BIGNUM *p;

    const BIGNUM *q;

    const BIGNUM *g;

#endif

};

/*

 * The private key length values are taken from RFC7919 with the values for

 * MODP primes given the same lengths as the equivalent FFDHE.

 * The MODP 1536 value is approximated.

 */

static const DH_NAMED_GROUP dh_named_groups[] = {

    FFDHE(2048, 225),

    FFDHE(3072, 275),

    FFDHE(4096, 325),

    FFDHE(6144, 375),

    FFDHE(8192, 400),

#ifndef FIPS_MODULE

    MODP(1536, 200),

#endif

    MODP(2048, 225),

    MODP(3072, 275),

    MODP(4096, 325),

    MODP(6144, 375),

    MODP(8192, 400),

    /*

     * Additional dh named groups from RFC 5114 that have a different g.

     * The uid can be any unique identifier.

     */

#ifndef FIPS_MODULE

    RFC5114("dh_1024_160", 1, 1024, 1024_160),

    RFC5114("dh_2048_224", 2, 2048, 2048_224),

    RFC5114("dh_2048_256", 3, 2048, 2048_256),

#endif

};

const DH_NAMED_GROUP *ossl_ffc_name_to_dh_named_group(const char *name)

{

    size_t i;

    for (i = 0; i < OSSL_NELEM(dh_named_groups); ++i) {

        if (OPENSSL_strcasecmp(dh_named_groups[i].name, name) == 0)

            return &dh_named_groups[i];

    }

    return NULL;

}

const DH_NAMED_GROUP *ossl_ffc_uid_to_dh_named_group(int uid)

{

    size_t i;

    for (i = 0; i < OSSL_NELEM(dh_named_groups); ++i) {

        if (dh_named_groups[i].uid == uid)

            return &dh_named_groups[i];

    }

    return NULL;

}

#ifndef OPENSSL_NO_DH

const DH_NAMED_GROUP *ossl_ffc_numbers_to_dh_named_group(const BIGNUM *p,

                                                         const BIGNUM *q,

                                                         const BIGNUM *g)

{

    size_t i;

    for (i = 0; i < OSSL_NELEM(dh_named_groups); ++i) {

        /* Keep searching until a matching p and g is found */

        if (BN_cmp(p, dh_named_groups[i].p) == 0

            && BN_cmp(g, dh_named_groups[i].g) == 0

            /* Verify q is correct if it exists */

            && (q == NULL || BN_cmp(q, dh_named_groups[i].q) == 0))

            return &dh_named_groups[i];

    }

    return NULL;

}

#endif

int ossl_ffc_named_group_get_uid(const DH_NAMED_GROUP *group)

{

    if (group == NULL)

        return NID_undef;

    return group->uid;

}

const char *ossl_ffc_named_group_get_name(const DH_NAMED_GROUP *group)

{

    if (group == NULL)

        return NULL;

    return group->name;

}

#ifndef OPENSSL_NO_DH

int ossl_ffc_named_group_get_keylength(const DH_NAMED_GROUP *group)

{

    if (group == NULL)

        return 0;

    return group->keylength;

}

const BIGNUM *ossl_ffc_named_group_get_q(const DH_NAMED_GROUP *group)

{

    if (group == NULL)

        return NULL;

    return group->q;

}

int ossl_ffc_named_group_set(FFC_PARAMS *ffc, const DH_NAMED_GROUP *group)

{

    if (ffc == NULL || group == NULL)

        return 0;

    ossl_ffc_params_set0_pqg(ffc, (BIGNUM *)group->p, (BIGNUM *)group->q,

                             (BIGNUM *)group->g);

    ffc->keylength = group->keylength;

    /* flush the cached nid, The DH layer is responsible for caching */

    ffc->nid = NID_undef;

    return 1;

}

#endif