




#include "internal/deprecated.h"

#include <stdio.h>
#include "internal/cryptlib.h"
#include <openssl/bn.h>
#include <openssl/sha.h>
#include "crypto/dh.h"
#include "crypto/security_bits.h"
#include "dh_local.h"

#ifndef FIPS_MODULE
static int dh_builtin_genparams(DH *ret, int prime_len, int generator,
                                BN_GENCB *cb);
#endif 

int ossl_dh_generate_ffc_parameters(DH *dh, int type, int pbits, int qbits,
                                    BN_GENCB *cb)
{
    int ret, res;

#ifndef FIPS_MODULE
    if (type == DH_PARAMGEN_TYPE_FIPS_186_2)
        ret = ossl_ffc_params_FIPS186_2_generate(dh->libctx, &dh->params,
                                                 FFC_PARAM_TYPE_DH,
                                                 pbits, qbits, &res, cb);
    else
#endif
        ret = ossl_ffc_params_FIPS186_4_generate(dh->libctx, &dh->params,
                                                 FFC_PARAM_TYPE_DH,
                                                 pbits, qbits, &res, cb);
    if (ret > 0)
        dh->dirty_cnt++;
    return ret;
}

int ossl_dh_get_named_group_uid_from_size(int pbits)
{
    
    int nid;

    switch (pbits) {
    case 2048:
        nid = NID_ffdhe2048;
        break;
    case 3072:
        nid = NID_ffdhe3072;
        break;
    case 4096:
        nid = NID_ffdhe4096;
        break;
    case 6144:
        nid = NID_ffdhe6144;
        break;
    case 8192:
        nid = NID_ffdhe8192;
        break;
    
    default:
        return NID_undef;
    }
    return nid;
}

#ifdef FIPS_MODULE

static int dh_gen_named_group(OSSL_LIB_CTX *libctx, DH *ret, int prime_len)
{
    DH *dh;
    int ok = 0;
    int nid = ossl_dh_get_named_group_uid_from_size(prime_len);

    if (nid == NID_undef)
        return 0;

    dh = ossl_dh_new_by_nid_ex(libctx, nid);
    if (dh != NULL
        && ossl_ffc_params_copy(&ret->params, &dh->params)) {
        ok = 1;
        ret->dirty_cnt++;
    }
    DH_free(dh);
    return ok;
}
#endif 

int DH_generate_parameters_ex(DH *ret, int prime_len, int generator,
                              BN_GENCB *cb)
{
#ifdef FIPS_MODULE
    if (generator != 2)
        return 0;
    return dh_gen_named_group(ret->libctx, ret, prime_len);
#else
    if (ret->meth->generate_params)
        return ret->meth->generate_params(ret, prime_len, generator, cb);
    return dh_builtin_genparams(ret, prime_len, generator, cb);
#endif 
}

#ifndef FIPS_MODULE

static int dh_builtin_genparams(DH *ret, int prime_len, int generator,
                                BN_GENCB *cb)
{
    BIGNUM *t1, *t2;
    int g, ok = -1;
    BN_CTX *ctx = NULL;

    if (prime_len > OPENSSL_DH_MAX_MODULUS_BITS) {
        ERR_raise(ERR_LIB_DH, DH_R_MODULUS_TOO_LARGE);
        return 0;
    }

    if (prime_len < DH_MIN_MODULUS_BITS) {
        ERR_raise(ERR_LIB_DH, DH_R_MODULUS_TOO_SMALL);
        return 0;
    }

    ctx = BN_CTX_new_ex(ret->libctx);
    if (ctx == NULL)
        goto err;
    BN_CTX_start(ctx);
    t1 = BN_CTX_get(ctx);
    t2 = BN_CTX_get(ctx);
    if (t2 == NULL)
        goto err;

    
    if (ret->params.p == NULL && ((ret->params.p = BN_new()) == NULL))
        goto err;
    if (ret->params.g == NULL && ((ret->params.g = BN_new()) == NULL))
        goto err;

    if (generator <= 1) {
        ERR_raise(ERR_LIB_DH, DH_R_BAD_GENERATOR);
        goto err;
    }
    if (generator == DH_GENERATOR_2) {
        if (!BN_set_word(t1, 24))
            goto err;
        if (!BN_set_word(t2, 23))
            goto err;
        g = 2;
    } else if (generator == DH_GENERATOR_5) {
        if (!BN_set_word(t1, 60))
            goto err;
        if (!BN_set_word(t2, 59))
            goto err;
        g = 5;
    } else {
        
        if (!BN_set_word(t1, 12))
            goto err;
        if (!BN_set_word(t2, 11))
            goto err;
        g = generator;
    }

    if (!BN_generate_prime_ex2(ret->params.p, prime_len, 1, t1, t2, cb, ctx))
        goto err;
    if (!BN_GENCB_call(cb, 3, 0))
        goto err;
    if (!BN_set_word(ret->params.g, g))
        goto err;
    
    ret->length = (2 * ossl_ifc_ffc_compute_security_bits(prime_len)
                   + 24) / 25 * 25;
    ret->dirty_cnt++;
    ok = 1;
 err:
    if (ok == -1) {
        ERR_raise(ERR_LIB_DH, ERR_R_BN_LIB);
        ok = 0;
    }

    BN_CTX_end(ctx);
    BN_CTX_free(ctx);
    return ok;
}
#endif 
