/*
 * Copyright 2019-2020 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 <string.h> /* memset */
#include <openssl/core_names.h>
#include "internal/ffc.h"
#include "internal/param_build_set.h"
#include "internal/nelem.h"
#include "e_os.h" /* strcasecmp */

#ifndef FIPS_MODULE
# include <openssl/asn1.h> /* ossl_ffc_params_print */
#endif

void ossl_ffc_params_init(FFC_PARAMS *params)
{
    memset(params, 0, sizeof(*params));
    params->pcounter = -1;
    params->gindex = FFC_UNVERIFIABLE_GINDEX;
    params->flags = FFC_PARAM_FLAG_VALIDATE_ALL;
}

void ossl_ffc_params_cleanup(FFC_PARAMS *params)
{
    BN_free(params->p);
    BN_free(params->q);
    BN_free(params->g);
    BN_free(params->j);
    OPENSSL_free(params->seed);
    ossl_ffc_params_init(params);
}

void ossl_ffc_params_set0_pqg(FFC_PARAMS *d, BIGNUM *p, BIGNUM *q, BIGNUM *g)
{
    if (p != NULL && p != d->p) {
        BN_free(d->p);
        d->p = p;
    }
    if (q != NULL && q != d->q) {
        BN_free(d->q);
        d->q = q;
    }
    if (g != NULL && g != d->g) {
        BN_free(d->g);
        d->g = g;
    }
}

void ossl_ffc_params_get0_pqg(const FFC_PARAMS *d, const BIGNUM **p,
                              const BIGNUM **q, const BIGNUM **g)
{
    if (p != NULL)
        *p = d->p;
    if (q != NULL)
        *q = d->q;
    if (g != NULL)
        *g = d->g;
}


/* j is the 'cofactor' that is optionally output for ASN1. */
void ossl_ffc_params_set0_j(FFC_PARAMS *d, BIGNUM *j)
{
    BN_free(d->j);
    d->j = NULL;
    if (j != NULL)
        d->j = j;
}

int ossl_ffc_params_set_seed(FFC_PARAMS *params,
                             const unsigned char *seed, size_t seedlen)
{
    if (params == NULL)
        return 0;

    if (params->seed != NULL) {
        if (params->seed == seed)
            return 1;
        OPENSSL_free(params->seed);
    }

    if (seed != NULL && seedlen > 0) {
        params->seed = OPENSSL_memdup(seed, seedlen);
        if (params->seed == NULL)
            return 0;
        params->seedlen = seedlen;
    } else {
        params->seed = NULL;
        params->seedlen = 0;
    }
    return 1;
}

void ossl_ffc_params_set_gindex(FFC_PARAMS *params, int index)
{
    params->gindex = index;
}

void ossl_ffc_params_set_pcounter(FFC_PARAMS *params, int index)
{
    params->pcounter = index;
}

void ossl_ffc_params_set_h(FFC_PARAMS *params, int index)
{
    params->h = index;
}

void ossl_ffc_params_set_flags(FFC_PARAMS *params, unsigned int flags)
{
    params->flags = flags;
}

void ossl_ffc_params_enable_flags(FFC_PARAMS *params, unsigned int flags,
                                  int enable)
{
    if (enable)
        params->flags |= flags;
    else
        params->flags &= ~flags;
}

int ossl_ffc_set_digest(FFC_PARAMS *params, const char *alg, const char *props)
{
    params->mdname = alg;
    params->mdprops = props;
    return 1;
}

int ossl_ffc_params_set_validate_params(FFC_PARAMS *params,
                                        const unsigned char *seed,
                                        size_t seedlen, int counter)
{
    if (!ossl_ffc_params_set_seed(params, seed, seedlen))
        return 0;
    params->pcounter = counter;
    return 1;
}

void ossl_ffc_params_get_validate_params(const FFC_PARAMS *params,
                                         unsigned char **seed, size_t *seedlen,
                                         int *pcounter)
{
    if (seed != NULL)
        *seed = params->seed;
    if (seedlen != NULL)
        *seedlen = params->seedlen;
    if (pcounter != NULL)
        *pcounter = params->pcounter;
}

static int ffc_bn_cpy(BIGNUM **dst, const BIGNUM *src)
{
    BIGNUM *a;

    /*
     * If source is read only just copy the pointer, so
     * we don't have to reallocate it.
     */
    if (src == NULL)
        a = NULL;
    else if (BN_get_flags(src, BN_FLG_STATIC_DATA)
             && !BN_get_flags(src, BN_FLG_MALLOCED))
        a = (BIGNUM *)src;
    else if ((a = BN_dup(src)) == NULL)
        return 0;
    BN_clear_free(*dst);
    *dst = a;
    return 1;
}

int ossl_ffc_params_copy(FFC_PARAMS *dst, const FFC_PARAMS *src)
{
    if (!ffc_bn_cpy(&dst->p, src->p)
        || !ffc_bn_cpy(&dst->g, src->g)
        || !ffc_bn_cpy(&dst->q, src->q)
        || !ffc_bn_cpy(&dst->j, src->j))
        return 0;

    OPENSSL_free(dst->seed);
    dst->seedlen = src->seedlen;
    if (src->seed != NULL) {
        dst->seed = OPENSSL_memdup(src->seed, src->seedlen);
        if  (dst->seed == NULL)
            return 0;
    } else {
        dst->seed = NULL;
    }
    dst->nid = src->nid;
    dst->pcounter = src->pcounter;
    dst->h = src->h;
    dst->gindex = src->gindex;
    return 1;
}

int ossl_ffc_params_cmp(const FFC_PARAMS *a, const FFC_PARAMS *b, int ignore_q)
{
    return BN_cmp(a->p, b->p) == 0
           && BN_cmp(a->g, b->g) == 0
           && (ignore_q || BN_cmp(a->q, b->q) == 0); /* Note: q may be NULL */
}

static const OSSL_ITEM flag_map[] = {
    { FFC_PARAM_FLAG_VALIDATE_PQ, OSSL_FFC_PARAM_VALIDATE_PQ },
    { FFC_PARAM_FLAG_VALIDATE_G, OSSL_FFC_PARAM_VALIDATE_G },
    { FFC_PARAM_FLAG_VALIDATE_ALL, OSSL_FFC_PARAM_VALIDATE_PQG },
    { 0, "" }
};

int ossl_ffc_params_flags_from_name(const char *name)
{
    size_t i;

    for (i = 0; i < OSSL_NELEM(flag_map); ++i) {
        if (strcasecmp(flag_map[i].ptr, name) == 0)
            return flag_map[i].id;
    }
    return NID_undef;
}

const char *ossl_ffc_params_flags_to_name(int flags)
{
    size_t i;

    flags &= FFC_PARAM_FLAG_VALIDATE_ALL;
    for (i = 0; i < OSSL_NELEM(flag_map); ++i) {
        if ((int)flag_map[i].id == flags)
            return flag_map[i].ptr;
    }
    return "";
}

int ossl_ffc_params_todata(const FFC_PARAMS *ffc, OSSL_PARAM_BLD *bld,
                      OSSL_PARAM params[])
{
    if (ffc == NULL)
        return 0;

    if (ffc->p != NULL
        && !ossl_param_build_set_bn(bld, params, OSSL_PKEY_PARAM_FFC_P, ffc->p))
        return 0;
    if (ffc->q != NULL
        && !ossl_param_build_set_bn(bld, params, OSSL_PKEY_PARAM_FFC_Q, ffc->q))
        return 0;
    if (ffc->g != NULL
        && !ossl_param_build_set_bn(bld, params, OSSL_PKEY_PARAM_FFC_G, ffc->g))
        return 0;
    if (ffc->j != NULL
        && !ossl_param_build_set_bn(bld, params, OSSL_PKEY_PARAM_FFC_COFACTOR,
                                    ffc->j))
        return 0;
    if (!ossl_param_build_set_int(bld, params, OSSL_PKEY_PARAM_FFC_GINDEX,
                                  ffc->gindex))
        return 0;
    if (!ossl_param_build_set_int(bld, params, OSSL_PKEY_PARAM_FFC_PCOUNTER,
                                  ffc->pcounter))
        return 0;
    if (!ossl_param_build_set_int(bld, params, OSSL_PKEY_PARAM_FFC_H, ffc->h))
        return 0;
    if (ffc->seed != NULL
        && !ossl_param_build_set_octet_string(bld, params,
                                              OSSL_PKEY_PARAM_FFC_SEED,
                                              ffc->seed, ffc->seedlen))
        return 0;
    if (ffc->nid != NID_undef) {
#ifndef OPENSSL_NO_DH
        const char *name = ossl_ffc_named_group_from_uid(ffc->nid);

        if (name == NULL
            || !ossl_param_build_set_utf8_string(bld, params,
                                                 OSSL_PKEY_PARAM_GROUP_NAME,
                                                 name))
            return 0;
#else
        /* How could this be? We should not have a nid in a no-dh build. */
        return 0;
#endif
    }
    if (!ossl_param_build_set_utf8_string(bld, params,
                                          OSSL_PKEY_PARAM_FFC_VALIDATE_TYPE,
                                          ossl_ffc_params_flags_to_name(ffc->flags)))
        return 0;
    if (ffc->mdname != NULL
        && !ossl_param_build_set_utf8_string(bld, params,
                                             OSSL_PKEY_PARAM_FFC_DIGEST,
                                             ffc->mdname))
       return 0;
    if (ffc->mdprops != NULL
        && !ossl_param_build_set_utf8_string(bld, params,
                                             OSSL_PKEY_PARAM_FFC_DIGEST_PROPS,
                                             ffc->mdprops))
        return 0;
    return 1;
}

#ifndef FIPS_MODULE
int ossl_ffc_params_print(BIO *bp, const FFC_PARAMS *ffc, int indent)
{
    if (!ASN1_bn_print(bp, "prime P:", ffc->p, NULL, indent))
        goto err;
    if (!ASN1_bn_print(bp, "generator G:", ffc->g, NULL, indent))
        goto err;
    if (ffc->q != NULL
        && !ASN1_bn_print(bp, "subgroup order Q:", ffc->q, NULL, indent))
        goto err;
    if (ffc->j != NULL
        && !ASN1_bn_print(bp, "subgroup factor:", ffc->j, NULL, indent))
        goto err;
    if (ffc->seed != NULL) {
        size_t i;

        if (!BIO_indent(bp, indent, 128)
            || BIO_puts(bp, "seed:") <= 0)
            goto err;
        for (i = 0; i < ffc->seedlen; i++) {
            if ((i % 15) == 0) {
                if (BIO_puts(bp, "\n") <= 0
                    || !BIO_indent(bp, indent + 4, 128))
                    goto err;
            }
            if (BIO_printf(bp, "%02x%s", ffc->seed[i],
                           ((i + 1) == ffc->seedlen) ? "" : ":") <= 0)
                goto err;
        }
        if (BIO_write(bp, "\n", 1) <= 0)
            return 0;
    }
    if (ffc->pcounter != -1) {
        if (!BIO_indent(bp, indent, 128)
            || BIO_printf(bp, "counter: %d\n", ffc->pcounter) <= 0)
            goto err;
    }
    return 1;
err:
    return 0;
}
#endif /* FIPS_MODULE */