lib/dns/openssldh_link.c

/*
 * Portions Copyright (C) 1999-2002, 2004-2009, 2011-2017  Internet Systems Consortium, Inc. ("ISC")
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 * Portions Copyright (C) 1995-2000 by Network Associates, Inc.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC AND NETWORK ASSOCIATES DISCLAIMS
 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE
 * FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
 * IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

/*
 * Principal Author: Brian Wellington
 * $Id: openssldh_link.c,v 1.20 2011/01/11 23:47:13 tbox Exp $
 */

#ifdef OPENSSL

#include <config.h>

#include <pk11/site.h>

#ifndef PK11_DH_DISABLE

#include <ctype.h>

#include <isc/mem.h>
#include <isc/safe.h>
#include <isc/string.h>
#include <isc/util.h>

#include <dst/result.h>

#include "dst_internal.h"
#include "dst_openssl.h"
#include "dst_parse.h"

#define PRIME768 "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088" \
    "A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF25" \
    "F14374FE1356D6D51C245E485B576625E7EC6F44C42E9A63A3620FFFFFFFFFFFFFFFF"

#define PRIME1024 "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E08" \
    "8A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF2" \
    "5F14374FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406" \
    "B7EDEE386BFB5A899FA5AE9F24117C4B1FE649286651ECE65381FFFFFFFFFFFFFFFF"

#define PRIME1536 "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1" \
    "29024E088A67CC74020BBEA63B139B22514A08798E3404DD" \
    "EF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245" \
    "E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED" \
    "EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3D" \
    "C2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F" \
    "83655D23DCA3AD961C62F356208552BB9ED529077096966D" \
    "670C354E4ABC9804F1746C08CA237327FFFFFFFFFFFFFFFF"


static isc_result_t openssldh_todns(const dst_key_t *key, isc_buffer_t *data);

static BIGNUM *bn2, *bn768, *bn1024, *bn1536;

#if OPENSSL_VERSION_NUMBER < 0x10100000L || defined(LIBRESSL_VERSION_NUMBER)
/*
 * DH_get0_key, DH_set0_key, DH_get0_pqg and DH_set0_pqg
 * are from OpenSSL 1.1.0.
 */
static void
DH_get0_key(const DH *dh, const BIGNUM **pub_key, const BIGNUM **priv_key) {
    if (pub_key != NULL)
        *pub_key = dh->pub_key;
    if (priv_key != NULL)
        *priv_key = dh->priv_key;
}

static int
DH_set0_key(DH *dh, BIGNUM *pub_key, BIGNUM *priv_key) {
    /* Note that it is valid for priv_key to be NULL */
    if (pub_key == NULL)
        return 0;

    BN_free(dh->pub_key);
    BN_free(dh->priv_key);
    dh->pub_key = pub_key;
    dh->priv_key = priv_key;

    return 1;
}

static void
DH_get0_pqg(const DH *dh,
        const BIGNUM **p, const BIGNUM **q, const BIGNUM **g)
{
    if (p != NULL)
        *p = dh->p;
    if (q != NULL)
        *q = dh->q;
    if (g != NULL)
        *g = dh->g;
}

static int
DH_set0_pqg(DH *dh, BIGNUM *p, BIGNUM *q, BIGNUM *g) {
    /* q is optional */
    if (p == NULL || g == NULL)
        return(0);
    BN_free(dh->p);
    BN_free(dh->q);
    BN_free(dh->g);
    dh->p = p;
    dh->q = q;
    dh->g = g;

    if (q != NULL) {
        dh->length = BN_num_bits(q);
    }

    return(1);
}

#define DH_clear_flags(d, f) (d)->flags &= ~(f)

#endif

static isc_result_t
openssldh_computesecret(const dst_key_t *pub, const dst_key_t *priv,
            isc_buffer_t *secret)
{
    DH *dhpub, *dhpriv;
    const BIGNUM *pub_key = NULL;
    int ret;
    isc_region_t r;
    unsigned int len;

    REQUIRE(pub->keydata.dh != NULL);
    REQUIRE(priv->keydata.dh != NULL);

    dhpub = pub->keydata.dh;
    dhpriv = priv->keydata.dh;

    len = DH_size(dhpriv);
    isc_buffer_availableregion(secret, &r);
    if (r.length < len)
        return (ISC_R_NOSPACE);

    DH_get0_key(dhpub, &pub_key, NULL);
    ret = DH_compute_key(r.base, pub_key, dhpriv);
    if (ret <= 0)
        return (dst__openssl_toresult2("DH_compute_key",
                           DST_R_COMPUTESECRETFAILURE));
    isc_buffer_add(secret, len);
    return (ISC_R_SUCCESS);
}

static isc_boolean_t
openssldh_compare(const dst_key_t *key1, const dst_key_t *key2) {
    DH *dh1, *dh2;
    const BIGNUM *pub_key1 = NULL, *pub_key2 = NULL;
    const BIGNUM *priv_key1 = NULL, *priv_key2 = NULL;
    const BIGNUM *p1 = NULL, *g1 = NULL, *p2 = NULL, *g2 = NULL;

    dh1 = key1->keydata.dh;
    dh2 = key2->keydata.dh;

    if (dh1 == NULL && dh2 == NULL)
        return (ISC_TRUE);
    else if (dh1 == NULL || dh2 == NULL)
        return (ISC_FALSE);

    DH_get0_key(dh1, &pub_key1, &priv_key1);
    DH_get0_key(dh2, &pub_key2, &priv_key2);
    DH_get0_pqg(dh1, &p1, NULL, &g1);
    DH_get0_pqg(dh2, &p2, NULL, &g2);

    if (BN_cmp(p1, p2) != 0 || BN_cmp(g1, g2) != 0 ||
        BN_cmp(pub_key1, pub_key2) != 0)
        return (ISC_FALSE);

    if (priv_key1 != NULL || priv_key2 != NULL) {
        if (priv_key1 == NULL || priv_key2 == NULL)
            return (ISC_FALSE);
        if (BN_cmp(priv_key1, priv_key2) != 0)
            return (ISC_FALSE);
    }
    return (ISC_TRUE);
}

static isc_boolean_t
openssldh_paramcompare(const dst_key_t *key1, const dst_key_t *key2) {
    DH *dh1, *dh2;
    const BIGNUM *p1 = NULL, *g1 = NULL, *p2 = NULL, *g2 = NULL;

    dh1 = key1->keydata.dh;
    dh2 = key2->keydata.dh;

    if (dh1 == NULL && dh2 == NULL)
        return (ISC_TRUE);
    else if (dh1 == NULL || dh2 == NULL)
        return (ISC_FALSE);

    DH_get0_pqg(dh1, &p1, NULL, &g1);
    DH_get0_pqg(dh2, &p2, NULL, &g2);

    if (BN_cmp(p1, p2) != 0 || BN_cmp(g1, g2) != 0)
        return (ISC_FALSE);
    return (ISC_TRUE);
}

#if OPENSSL_VERSION_NUMBER > 0x00908000L
static int
progress_cb(int p, int n, BN_GENCB *cb) {
    union {
        void *dptr;
        void (*fptr)(int);
    } u;

    UNUSED(n);

    u.dptr = BN_GENCB_get_arg(cb);
    if (u.fptr != NULL)
        u.fptr(p);
    return (1);
}
#endif

static isc_result_t
openssldh_generate(dst_key_t *key, int generator, void (*callback)(int)) {
    DH *dh = NULL;
#if OPENSSL_VERSION_NUMBER > 0x00908000L
    BN_GENCB *cb;
#if OPENSSL_VERSION_NUMBER < 0x10100000L || defined(LIBRESSL_VERSION_NUMBER)
    BN_GENCB _cb;
#endif
    union {
        void *dptr;
        void (*fptr)(int);
    } u;
#else

    UNUSED(callback);
#endif

    if (generator == 0) {
        if (key->key_size == 768 ||
            key->key_size == 1024 ||
            key->key_size == 1536)
        {
            BIGNUM *p, *g;
            dh = DH_new();
            if (key->key_size == 768)
                p = BN_dup(bn768);
            else if (key->key_size == 1024)
                p = BN_dup(bn1024);
            else
                p = BN_dup(bn1536);
            g = BN_dup(bn2);
            if (dh == NULL || p == NULL || g == NULL) {
                if (dh != NULL)
                    DH_free(dh);
                if (p != NULL)
                    BN_free(p);
                if (g != NULL)
                    BN_free(g);
                return (dst__openssl_toresult(ISC_R_NOMEMORY));
            }
            DH_set0_pqg(dh, p, NULL, g);
        } else
            generator = 2;
    }

    if (generator != 0) {
#if OPENSSL_VERSION_NUMBER > 0x00908000L
        dh = DH_new();
        if (dh == NULL)
            return (dst__openssl_toresult(ISC_R_NOMEMORY));
        cb = BN_GENCB_new();
#if OPENSSL_VERSION_NUMBER >= 0x10100000L && !defined(LIBRESSL_VERSION_NUMBER)
        if (cb == NULL) {
            DH_free(dh);
            return (dst__openssl_toresult(ISC_R_NOMEMORY));
        }
#endif
        if (callback == NULL) {
            BN_GENCB_set_old(cb, NULL, NULL);
        } else {
            u.fptr = callback;
            BN_GENCB_set(cb, &progress_cb, u.dptr);
        }

        if (!DH_generate_parameters_ex(dh, key->key_size, generator,
                           cb)) {
            DH_free(dh);
            BN_GENCB_free(cb);
            return (dst__openssl_toresult2(
                    "DH_generate_parameters_ex",
                    DST_R_OPENSSLFAILURE));
        }
        BN_GENCB_free(cb);
#else
        dh = DH_generate_parameters(key->key_size, generator,
                        NULL, NULL);
        if (dh == NULL)
            return (dst__openssl_toresult2(
                    "DH_generate_parameters",
                    DST_R_OPENSSLFAILURE));
#endif
    }

    if (DH_generate_key(dh) == 0) {
        DH_free(dh);
        return (dst__openssl_toresult2("DH_generate_key",
                           DST_R_OPENSSLFAILURE));
    }
    DH_clear_flags(dh, DH_FLAG_CACHE_MONT_P);
    key->keydata.dh = dh;

    return (ISC_R_SUCCESS);
}

static isc_boolean_t
openssldh_isprivate(const dst_key_t *key) {
    DH *dh = key->keydata.dh;
    const BIGNUM *priv_key = NULL;

    DH_get0_key(dh, NULL, &priv_key);
    return (ISC_TF(dh != NULL && priv_key != NULL));
}

static void
openssldh_destroy(dst_key_t *key) {
    DH *dh = key->keydata.dh;

    if (dh == NULL)
        return;

    DH_free(dh);
    key->keydata.dh = NULL;
}

static void
uint16_toregion(isc_uint16_t val, isc_region_t *region) {
    *region->base = (val & 0xff00) >> 8;
    isc_region_consume(region, 1);
    *region->base = (val & 0x00ff);
    isc_region_consume(region, 1);
}

static isc_uint16_t
uint16_fromregion(isc_region_t *region) {
    isc_uint16_t val;
    unsigned char *cp = region->base;

    val = ((unsigned int)(cp[0])) << 8;
    val |= ((unsigned int)(cp[1]));

    isc_region_consume(region, 2);

    return (val);
}

static isc_result_t
openssldh_todns(const dst_key_t *key, isc_buffer_t *data) {
    DH *dh;
    const BIGNUM *pub_key = NULL, *p = NULL, *g = NULL;
    isc_region_t r;
    isc_uint16_t dnslen, plen, glen, publen;

    REQUIRE(key->keydata.dh != NULL);

    dh = key->keydata.dh;

    isc_buffer_availableregion(data, &r);

    DH_get0_pqg(dh, &p, NULL, &g);
    if (BN_cmp(g, bn2) == 0 &&
        (BN_cmp(p, bn768) == 0 ||
         BN_cmp(p, bn1024) == 0 ||
         BN_cmp(p, bn1536) == 0)) {
        plen = 1;
        glen = 0;
    }
    else {
        plen = BN_num_bytes(p);
        glen = BN_num_bytes(g);
    }
    DH_get0_key(dh, &pub_key, NULL);
    publen = BN_num_bytes(pub_key);
    dnslen = plen + glen + publen + 6;
    if (r.length < (unsigned int) dnslen)
        return (ISC_R_NOSPACE);

    uint16_toregion(plen, &r);
    if (plen == 1) {
        if (BN_cmp(p, bn768) == 0)
            *r.base = 1;
        else if (BN_cmp(p, bn1024) == 0)
            *r.base = 2;
        else
            *r.base = 3;
    } else
        BN_bn2bin(p, r.base);
    isc_region_consume(&r, plen);

    uint16_toregion(glen, &r);
    if (glen > 0)
        BN_bn2bin(g, r.base);
    isc_region_consume(&r, glen);

    uint16_toregion(publen, &r);
    BN_bn2bin(pub_key, r.base);
    isc_region_consume(&r, publen);

    isc_buffer_add(data, dnslen);

    return (ISC_R_SUCCESS);
}

static isc_result_t
openssldh_fromdns(dst_key_t *key, isc_buffer_t *data) {
    DH *dh;
    BIGNUM *pub_key = NULL, *p = NULL, *g = NULL;
    isc_region_t r;
    isc_uint16_t plen, glen, publen;
    int special = 0;

    isc_buffer_remainingregion(data, &r);
    if (r.length == 0)
        return (ISC_R_SUCCESS);

    dh = DH_new();
    if (dh == NULL)
        return (dst__openssl_toresult(ISC_R_NOMEMORY));
    DH_clear_flags(dh, DH_FLAG_CACHE_MONT_P);

    /*
     * Read the prime length.  1 & 2 are table entries, > 16 means a
     * prime follows, otherwise an error.
     */
    if (r.length < 2) {
        DH_free(dh);
        return (DST_R_INVALIDPUBLICKEY);
    }
    plen = uint16_fromregion(&r);
    if (plen < 16 && plen != 1 && plen != 2) {
        DH_free(dh);
        return (DST_R_INVALIDPUBLICKEY);
    }
    if (r.length < plen) {
        DH_free(dh);
        return (DST_R_INVALIDPUBLICKEY);
    }
    if (plen == 1 || plen == 2) {
        if (plen == 1) {
            special = *r.base;
            isc_region_consume(&r, 1);
        } else {
            special = uint16_fromregion(&r);
        }
        switch (special) {
            case 1:
                p = BN_dup(bn768);
                break;
            case 2:
                p = BN_dup(bn1024);
                break;
            case 3:
                p = BN_dup(bn1536);
                break;
            default:
                DH_free(dh);
                return (DST_R_INVALIDPUBLICKEY);
        }
    } else {
        p = BN_bin2bn(r.base, plen, NULL);
        isc_region_consume(&r, plen);
    }

    /*
     * Read the generator length.  This should be 0 if the prime was
     * special, but it might not be.  If it's 0 and the prime is not
     * special, we have a problem.
     */
    if (r.length < 2) {
        DH_free(dh);
        return (DST_R_INVALIDPUBLICKEY);
    }
    glen = uint16_fromregion(&r);
    if (r.length < glen) {
        DH_free(dh);
        return (DST_R_INVALIDPUBLICKEY);
    }
    if (special != 0) {
        if (glen == 0)
            g = BN_dup(bn2);
        else {
            g = BN_bin2bn(r.base, glen, NULL);
            if (g != NULL && BN_cmp(g, bn2) != 0) {
                DH_free(dh);
                BN_free(g);
                return (DST_R_INVALIDPUBLICKEY);
            }
        }
    } else {
        if (glen == 0) {
            DH_free(dh);
            return (DST_R_INVALIDPUBLICKEY);
        }
        g = BN_bin2bn(r.base, glen, NULL);
    }
    isc_region_consume(&r, glen);

    if (p == NULL || g == NULL) {
        DH_free(dh);
        if (p != NULL)
            BN_free(p);
        if (g != NULL)
            BN_free(g);
        return (dst__openssl_toresult(ISC_R_NOMEMORY));
    }
    DH_set0_pqg(dh, p, NULL, g);

    if (r.length < 2) {
        DH_free(dh);
        return (DST_R_INVALIDPUBLICKEY);
    }
    publen = uint16_fromregion(&r);
    if (r.length < publen) {
        DH_free(dh);
        return (DST_R_INVALIDPUBLICKEY);
    }
    pub_key = BN_bin2bn(r.base, publen, NULL);
    if (pub_key == NULL) {
        DH_free(dh);
        return (dst__openssl_toresult(ISC_R_NOMEMORY));
    }
    DH_set0_key(dh, pub_key, NULL);
    isc_region_consume(&r, publen);

    key->key_size = BN_num_bits(p);

    isc_buffer_forward(data, plen + glen + publen + 6);

    key->keydata.dh = dh;

    return (ISC_R_SUCCESS);
}

static isc_result_t
openssldh_tofile(const dst_key_t *key, const char *directory) {
    int i;
    DH *dh;
    const BIGNUM *pub_key = NULL, *priv_key = NULL, *p = NULL, *g = NULL;
    dst_private_t priv;
    unsigned char *bufs[4];
    isc_result_t result;

    if (key->keydata.dh == NULL)
        return (DST_R_NULLKEY);

    if (key->external)
        return (DST_R_EXTERNALKEY);

    dh = key->keydata.dh;
    DH_get0_key(dh, &pub_key, &priv_key);
    DH_get0_pqg(dh, &p, NULL, &g);

    memset(bufs, 0, sizeof(bufs));
    for (i = 0; i < 4; i++) {
        bufs[i] = isc_mem_get(key->mctx, BN_num_bytes(p));
        if (bufs[i] == NULL) {
            result = ISC_R_NOMEMORY;
            goto fail;
        }
    }

    i = 0;

    priv.elements[i].tag = TAG_DH_PRIME;
    priv.elements[i].length = BN_num_bytes(p);
    BN_bn2bin(p, bufs[i]);
    priv.elements[i].data = bufs[i];
    i++;

    priv.elements[i].tag = TAG_DH_GENERATOR;
    priv.elements[i].length = BN_num_bytes(g);
    BN_bn2bin(g, bufs[i]);
    priv.elements[i].data = bufs[i];
    i++;

    priv.elements[i].tag = TAG_DH_PRIVATE;
    priv.elements[i].length = BN_num_bytes(priv_key);
    BN_bn2bin(priv_key, bufs[i]);
    priv.elements[i].data = bufs[i];
    i++;

    priv.elements[i].tag = TAG_DH_PUBLIC;
    priv.elements[i].length = BN_num_bytes(pub_key);
    BN_bn2bin(pub_key, bufs[i]);
    priv.elements[i].data = bufs[i];
    i++;

    priv.nelements = i;
    result = dst__privstruct_writefile(key, &priv, directory);
 fail:
    for (i = 0; i < 4; i++) {
        if (bufs[i] == NULL)
            break;
        isc_mem_put(key->mctx, bufs[i], BN_num_bytes(p));
    }
    return (result);
}

static isc_result_t
openssldh_parse(dst_key_t *key, isc_lex_t *lexer, dst_key_t *pub) {
    dst_private_t priv;
    isc_result_t ret;
    int i;
    DH *dh = NULL;
    BIGNUM *pub_key = NULL, *priv_key = NULL, *p = NULL, *g = NULL;
    isc_mem_t *mctx;
#define DST_RET(a) {ret = a; goto err;}

    UNUSED(pub);
    mctx = key->mctx;

    /* read private key file */
    ret = dst__privstruct_parse(key, DST_ALG_DH, lexer, mctx, &priv);
    if (ret != ISC_R_SUCCESS)
        return (ret);

    if (key->external)
        DST_RET(DST_R_EXTERNALKEY);

    dh = DH_new();
    if (dh == NULL)
        DST_RET(ISC_R_NOMEMORY);
    DH_clear_flags(dh, DH_FLAG_CACHE_MONT_P);
    key->keydata.dh = dh;

    for (i = 0; i < priv.nelements; i++) {
        BIGNUM *bn;
        bn = BN_bin2bn(priv.elements[i].data,
                   priv.elements[i].length, NULL);
        if (bn == NULL)
            DST_RET(ISC_R_NOMEMORY);

        switch (priv.elements[i].tag) {
            case TAG_DH_PRIME:
                p = bn;
                break;
            case TAG_DH_GENERATOR:
                g = bn;
                break;
            case TAG_DH_PRIVATE:
                priv_key = bn;
                break;
            case TAG_DH_PUBLIC:
                pub_key = bn;
                break;
        }
    }
    dst__privstruct_free(&priv, mctx);
    DH_set0_key(dh, pub_key, priv_key);
    DH_set0_pqg(dh, p, NULL, g);

    key->key_size = BN_num_bits(p);
    return (ISC_R_SUCCESS);

 err:
    if (p != NULL)
        BN_free(p);
    if (g != NULL)
        BN_free(g);
    if (pub_key != NULL)
        BN_free(pub_key);
    if (priv_key != NULL)
        BN_free(priv_key);
    openssldh_destroy(key);
    dst__privstruct_free(&priv, mctx);
    isc_safe_memwipe(&priv, sizeof(priv));
    return (ret);
}

static void
BN_fromhex(BIGNUM *b, const char *str) {
    static const char hexdigits[] = "0123456789abcdef";
    unsigned char data[512];
    unsigned int i;
    BIGNUM *out;

    RUNTIME_CHECK(strlen(str) < 1024U && strlen(str) % 2 == 0U);
    for (i = 0; i < strlen(str); i += 2) {
        const char *s;
        unsigned int high, low;

        s = strchr(hexdigits, tolower((unsigned char)str[i]));
        RUNTIME_CHECK(s != NULL);
        high = (unsigned int)(s - hexdigits);

        s = strchr(hexdigits, tolower((unsigned char)str[i + 1]));
        RUNTIME_CHECK(s != NULL);
        low = (unsigned int)(s - hexdigits);

        data[i/2] = (unsigned char)((high << 4) + low);
    }
    out = BN_bin2bn(data, strlen(str)/2, b);
    RUNTIME_CHECK(out != NULL);
}

static void
openssldh_cleanup(void) {
    BN_free(bn2);
    BN_free(bn768);
    BN_free(bn1024);
    BN_free(bn1536);
}

static dst_func_t openssldh_functions = {
    NULL, /*%< createctx */
    NULL, /*%< createctx2 */
    NULL, /*%< destroyctx */
    NULL, /*%< adddata */
    NULL, /*%< openssldh_sign */
    NULL, /*%< openssldh_verify */
    NULL, /*%< openssldh_verify2 */
    openssldh_computesecret,
    openssldh_compare,
    openssldh_paramcompare,
    openssldh_generate,
    openssldh_isprivate,
    openssldh_destroy,
    openssldh_todns,
    openssldh_fromdns,
    openssldh_tofile,
    openssldh_parse,
    openssldh_cleanup,
    NULL, /*%< fromlabel */
    NULL, /*%< dump */
    NULL, /*%< restore */
};

isc_result_t
dst__openssldh_init(dst_func_t **funcp) {
    REQUIRE(funcp != NULL);
    if (*funcp == NULL) {
        bn2 = BN_new();
        bn768 = BN_new();
        bn1024 = BN_new();
        bn1536 = BN_new();
        if (bn2 == NULL || bn768 == NULL ||
            bn1024 == NULL || bn1536 == NULL)
            goto cleanup;
        BN_set_word(bn2, 2);
        BN_fromhex(bn768, PRIME768);
        BN_fromhex(bn1024, PRIME1024);
        BN_fromhex(bn1536, PRIME1536);
        *funcp = &openssldh_functions;
    }
    return (ISC_R_SUCCESS);

 cleanup:
    if (bn2 != NULL) BN_free(bn2);
    if (bn768 != NULL) BN_free(bn768);
    if (bn1024 != NULL) BN_free(bn1024);
    if (bn1536 != NULL) BN_free(bn1536);
    return (ISC_R_NOMEMORY);
}
#endif /* !PK11_DH_DISABLE */

#else /* OPENSSL */

#include <isc/util.h>

EMPTY_TRANSLATION_UNIT

#endif /* OPENSSL */
/*! \file */