lib/dns/openssldsa_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.
 */

#ifdef OPENSSL
#ifndef USE_EVP
#define USE_EVP 1
#endif

#include <config.h>

#include <pk11/site.h>

#ifndef PK11_DSA_DISABLE

#include <string.h>

#include <isc/entropy.h>
#include <isc/mem.h>
#include <isc/safe.h>
#include <isc/sha1.h>
#include <isc/util.h>

#include <dst/result.h>

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

#include <openssl/dsa.h>

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

#if OPENSSL_VERSION_NUMBER < 0x10100000L || defined(LIBRESSL_VERSION_NUMBER)
static void
DSA_get0_pqg(const DSA *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;
}

static int
DSA_set0_pqg(DSA *d, BIGNUM *p, BIGNUM *q, BIGNUM *g) {
    if (p == NULL || q == NULL || g == NULL)
        return 0;
    BN_free(d->p);
    BN_free(d->q);
    BN_free(d->g);
    d->p = p;
    d->q = q;
    d->g = g;

    return 1;
}

static void
DSA_get0_key(const DSA *d, const BIGNUM **pub_key, const BIGNUM **priv_key) {
    if (pub_key != NULL)
        *pub_key = d->pub_key;
    if (priv_key != NULL)
        *priv_key = d->priv_key;
}

static int
DSA_set0_key(DSA *d, 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(d->pub_key);
    BN_free(d->priv_key);
    d->pub_key = pub_key;
    d->priv_key = priv_key;

    return 1;
}

static void
DSA_SIG_get0(const DSA_SIG *sig, const BIGNUM **pr, const BIGNUM **ps) {
    *pr = sig->r;
    *ps = sig->s;
}

static int
DSA_SIG_set0(DSA_SIG *sig, BIGNUM *r, BIGNUM *s) {
    if (r == NULL || s == NULL)
        return 0;

    BN_clear_free(sig->r);
    BN_clear_free(sig->s);
    sig->r = r;
    sig->s = s;

    return 1;
}


#define DSA_clear_flags(d, x) (d)->flags &= ~(x)

#endif

static isc_result_t
openssldsa_createctx(dst_key_t *key, dst_context_t *dctx) {
#if USE_EVP
    EVP_MD_CTX *evp_md_ctx;

    UNUSED(key);

    evp_md_ctx = EVP_MD_CTX_create();
    if (evp_md_ctx == NULL)
        return (ISC_R_NOMEMORY);

    if (!EVP_DigestInit_ex(evp_md_ctx, EVP_dss1(), NULL)) {
        EVP_MD_CTX_destroy(evp_md_ctx);
            return (ISC_R_FAILURE);
    }

    dctx->ctxdata.evp_md_ctx = evp_md_ctx;

    return (ISC_R_SUCCESS);
#else
    isc_sha1_t *sha1ctx;

    UNUSED(key);

    sha1ctx = isc_mem_get(dctx->mctx, sizeof(isc_sha1_t));
    if (sha1ctx == NULL)
        return (ISC_R_NOMEMORY);
    isc_sha1_init(sha1ctx);
    dctx->ctxdata.sha1ctx = sha1ctx;
    return (ISC_R_SUCCESS);
#endif
}

static void
openssldsa_destroyctx(dst_context_t *dctx) {
#if USE_EVP
    EVP_MD_CTX *evp_md_ctx = dctx->ctxdata.evp_md_ctx;

    if (evp_md_ctx != NULL) {
        EVP_MD_CTX_destroy(evp_md_ctx);
        dctx->ctxdata.evp_md_ctx = NULL;
    }
#else
    isc_sha1_t *sha1ctx = dctx->ctxdata.sha1ctx;

    if (sha1ctx != NULL) {
        isc_sha1_invalidate(sha1ctx);
        isc_mem_put(dctx->mctx, sha1ctx, sizeof(isc_sha1_t));
        dctx->ctxdata.sha1ctx = NULL;
    }
#endif
}

static isc_result_t
openssldsa_adddata(dst_context_t *dctx, const isc_region_t *data) {
#if USE_EVP
    EVP_MD_CTX *evp_md_ctx = dctx->ctxdata.evp_md_ctx;

    if (!EVP_DigestUpdate(evp_md_ctx, data->base, data->length)) {
        return (ISC_R_FAILURE);
    }
#else
    isc_sha1_t *sha1ctx = dctx->ctxdata.sha1ctx;

    isc_sha1_update(sha1ctx, data->base, data->length);
#endif
    return (ISC_R_SUCCESS);
}

static int
BN_bn2bin_fixed(const BIGNUM *bn, unsigned char *buf, int size) {
    int bytes = size - BN_num_bytes(bn);
    while (bytes-- > 0)
        *buf++ = 0;
    BN_bn2bin(bn, buf);
    return (size);
}

static isc_result_t
openssldsa_sign(dst_context_t *dctx, isc_buffer_t *sig) {
    dst_key_t *key = dctx->key;
    DSA *dsa = key->keydata.dsa;
    isc_region_t region;
    DSA_SIG *dsasig;
    const BIGNUM *r = 0, *s = NULL;
    unsigned int klen;
#if USE_EVP
    EVP_MD_CTX *evp_md_ctx = dctx->ctxdata.evp_md_ctx;
    EVP_PKEY *pkey;
    unsigned char *sigbuf;
    const unsigned char *sb;
    unsigned int siglen;
#else
    isc_sha1_t *sha1ctx = dctx->ctxdata.sha1ctx;
    unsigned char digest[ISC_SHA1_DIGESTLENGTH];
#endif

    isc_buffer_availableregion(sig, &region);
    if (region.length < ISC_SHA1_DIGESTLENGTH * 2 + 1)
        return (ISC_R_NOSPACE);

#if USE_EVP
    pkey = EVP_PKEY_new();
    if (pkey == NULL)
        return (ISC_R_NOMEMORY);
    if (!EVP_PKEY_set1_DSA(pkey, dsa)) {
        EVP_PKEY_free(pkey);
        return (ISC_R_FAILURE);
    }
    sigbuf = malloc(EVP_PKEY_size(pkey));
    if (sigbuf == NULL) {
        EVP_PKEY_free(pkey);
        return (ISC_R_NOMEMORY);
    }
    if (!EVP_SignFinal(evp_md_ctx, sigbuf, &siglen, pkey)) {
        EVP_PKEY_free(pkey);
        free(sigbuf);
        return (dst__openssl_toresult3(dctx->category,
                           "EVP_SignFinal",
                           ISC_R_FAILURE));
    }
    INSIST(EVP_PKEY_size(pkey) >= (int) siglen);
    EVP_PKEY_free(pkey);
    /* Convert from Dss-Sig-Value (RFC2459). */
    dsasig = DSA_SIG_new();
    if (dsasig == NULL) {
        free(sigbuf);
        return (ISC_R_NOMEMORY);
    }
    sb = sigbuf;
    if (d2i_DSA_SIG(&dsasig, &sb, (long) siglen) == NULL) {
        free(sigbuf);
        return (dst__openssl_toresult3(dctx->category,
                           "d2i_DSA_SIG",
                           ISC_R_FAILURE));
    }
    free(sigbuf);

#elif 0
    /* Only use EVP for the Digest */
    if (!EVP_DigestFinal_ex(evp_md_ctx, digest, &siglen)) {
        return (dst__openssl_toresult3(dctx->category,
                           "EVP_DigestFinal_ex",
                           ISC_R_FAILURE));
    }
    dsasig = DSA_do_sign(digest, ISC_SHA1_DIGESTLENGTH, dsa);
    if (dsasig == NULL)
        return (dst__openssl_toresult3(dctx->category,
                           "DSA_do_sign",
                           DST_R_SIGNFAILURE));
#else
    isc_sha1_final(sha1ctx, digest);

    dsasig = DSA_do_sign(digest, ISC_SHA1_DIGESTLENGTH, dsa);
    if (dsasig == NULL)
        return (dst__openssl_toresult3(dctx->category,
                           "DSA_do_sign",
                           DST_R_SIGNFAILURE));
#endif

    klen = (key->key_size - 512)/64;
    if (klen > 255)
        return (ISC_R_FAILURE);
    *region.base = klen;
    isc_region_consume(&region, 1);

    DSA_SIG_get0(dsasig, &r, &s);
    BN_bn2bin_fixed(r, region.base, ISC_SHA1_DIGESTLENGTH);
    isc_region_consume(&region, ISC_SHA1_DIGESTLENGTH);
    BN_bn2bin_fixed(s, region.base, ISC_SHA1_DIGESTLENGTH);
    isc_region_consume(&region, ISC_SHA1_DIGESTLENGTH);
    DSA_SIG_free(dsasig);
    isc_buffer_add(sig, ISC_SHA1_DIGESTLENGTH * 2 + 1);

    return (ISC_R_SUCCESS);
}

static isc_result_t
openssldsa_verify(dst_context_t *dctx, const isc_region_t *sig) {
    dst_key_t *key = dctx->key;
    DSA *dsa = key->keydata.dsa;
    BIGNUM *r = NULL, *s = NULL;
    int status = 0;
    unsigned char *cp = sig->base;
    DSA_SIG *dsasig;
#if USE_EVP
    EVP_MD_CTX *evp_md_ctx = dctx->ctxdata.evp_md_ctx;
#if 0
    EVP_PKEY *pkey;
    unsigned char *sigbuf;
#endif
    unsigned int siglen;
#else
    isc_sha1_t *sha1ctx = dctx->ctxdata.sha1ctx;
#endif
    unsigned char digest[ISC_SHA1_DIGESTLENGTH];


#if USE_EVP
#if 1
    /* Only use EVP for the digest */
    if (!EVP_DigestFinal_ex(evp_md_ctx, digest, &siglen)) {
        return (ISC_R_FAILURE);
    }
#endif
#else
    isc_sha1_final(sha1ctx, digest);
#endif

    if (sig->length != 2 * ISC_SHA1_DIGESTLENGTH + 1) {
        return (DST_R_VERIFYFAILURE);
    }

    cp++;   /*%< Skip T */
    dsasig = DSA_SIG_new();
    if (dsasig == NULL)
        return (ISC_R_NOMEMORY);
    r = BN_bin2bn(cp, ISC_SHA1_DIGESTLENGTH, NULL);
    cp += ISC_SHA1_DIGESTLENGTH;
    s = BN_bin2bn(cp, ISC_SHA1_DIGESTLENGTH, NULL);
    DSA_SIG_set0(dsasig, r, s);

#if 0
    pkey = EVP_PKEY_new();
    if (pkey == NULL)
        return (ISC_R_NOMEMORY);
    if (!EVP_PKEY_set1_DSA(pkey, dsa)) {
        EVP_PKEY_free(pkey);
        return (ISC_R_FAILURE);
    }
    /* Convert to Dss-Sig-Value (RFC2459). */
    sigbuf = malloc(EVP_PKEY_size(pkey) + 50);
    if (sigbuf == NULL) {
        EVP_PKEY_free(pkey);
        return (ISC_R_NOMEMORY);
    }
    siglen = (unsigned) i2d_DSA_SIG(dsasig, &sigbuf);
    INSIST(EVP_PKEY_size(pkey) >= (int) siglen);
    status = EVP_VerifyFinal(evp_md_ctx, sigbuf, siglen, pkey);
    EVP_PKEY_free(pkey);
    free(sigbuf);
#else
    status = DSA_do_verify(digest, ISC_SHA1_DIGESTLENGTH, dsasig, dsa);
#endif
    DSA_SIG_free(dsasig);
    switch (status) {
    case 1:
        return (ISC_R_SUCCESS);
    case 0:
        return (dst__openssl_toresult(DST_R_VERIFYFAILURE));
    default:
        return (dst__openssl_toresult3(dctx->category,
                           "DSA_do_verify",
                           DST_R_VERIFYFAILURE));
    }
}

static isc_boolean_t
openssldsa_compare(const dst_key_t *key1, const dst_key_t *key2) {
    DSA *dsa1, *dsa2;
    const BIGNUM *pub_key1 = NULL, *priv_key1 = NULL;
    const BIGNUM *pub_key2 = NULL, *priv_key2 = NULL;
    const BIGNUM *p1 = NULL, *q1 = NULL, *g1 = NULL;
    const BIGNUM *p2 = NULL, *q2 = NULL, *g2 = NULL;

    dsa1 = key1->keydata.dsa;
    dsa2 = key2->keydata.dsa;

    if (dsa1 == NULL && dsa2 == NULL)
        return (ISC_TRUE);
    else if (dsa1 == NULL || dsa2 == NULL)
        return (ISC_FALSE);

    DSA_get0_key(dsa1, &pub_key1, &priv_key1);
    DSA_get0_key(dsa2, &pub_key2, &priv_key2);
    DSA_get0_pqg(dsa1, &p1, &q1, &g1);
    DSA_get0_pqg(dsa2, &p2, &q2, &g2);

    if (BN_cmp(p1, p2) != 0 || BN_cmp(q1, q2) != 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))
            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
openssldsa_generate(dst_key_t *key, int unused, void (*callback)(int)) {
    DSA *dsa;
    unsigned char rand_array[ISC_SHA1_DIGESTLENGTH];
    isc_result_t result;
#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
    UNUSED(unused);

    result = dst__entropy_getdata(rand_array, sizeof(rand_array),
                      ISC_FALSE);
    if (result != ISC_R_SUCCESS)
        return (result);

#if OPENSSL_VERSION_NUMBER > 0x00908000L
    dsa = DSA_new();
    if (dsa == NULL)
        return (dst__openssl_toresult(DST_R_OPENSSLFAILURE));
    cb = BN_GENCB_new();
#if OPENSSL_VERSION_NUMBER >= 0x10100000L && !defined(LIBRESSL_VERSION_NUMBER)
    if (cb == NULL) {
        DSA_free(dsa);
        return (dst__openssl_toresult(DST_R_OPENSSLFAILURE));
    }
#endif
    if (callback == NULL) {
        BN_GENCB_set_old(cb, NULL, NULL);
    } else {
        u.fptr = callback;
        BN_GENCB_set(cb, &progress_cb, u.dptr);
    }

    if (!DSA_generate_parameters_ex(dsa, key->key_size, rand_array,
                    ISC_SHA1_DIGESTLENGTH,  NULL, NULL,
                    cb))
    {
        DSA_free(dsa);
        BN_GENCB_free(cb);
        return (dst__openssl_toresult2("DSA_generate_parameters_ex",
                           DST_R_OPENSSLFAILURE));
    }
    BN_GENCB_free(cb);
#else
    dsa = DSA_generate_parameters(key->key_size, rand_array,
                      ISC_SHA1_DIGESTLENGTH, NULL, NULL,
                      NULL, NULL);
    if (dsa == NULL)
        return (dst__openssl_toresult2("DSA_generate_parameters",
                           DST_R_OPENSSLFAILURE));
#endif

    if (DSA_generate_key(dsa) == 0) {
        DSA_free(dsa);
        return (dst__openssl_toresult2("DSA_generate_key",
                           DST_R_OPENSSLFAILURE));
    }

    DSA_clear_flags(dsa, DSA_FLAG_CACHE_MONT_P);

    key->keydata.dsa = dsa;

    return (ISC_R_SUCCESS);
}

static isc_boolean_t
openssldsa_isprivate(const dst_key_t *key) {
    DSA *dsa = key->keydata.dsa;
    const BIGNUM *priv_key = NULL;

    DSA_get0_key(dsa, NULL, &priv_key);
    return (ISC_TF(dsa != NULL && priv_key != NULL));
}

static void
openssldsa_destroy(dst_key_t *key) {
    DSA *dsa = key->keydata.dsa;
    DSA_free(dsa);
    key->keydata.dsa = NULL;
}


static isc_result_t
openssldsa_todns(const dst_key_t *key, isc_buffer_t *data) {
    DSA *dsa;
    const BIGNUM *pub_key, *p = NULL, *q = NULL, *g = NULL;
    isc_region_t r;
    int dnslen;
    unsigned int t, p_bytes;

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

    dsa = key->keydata.dsa;

    isc_buffer_availableregion(data, &r);

    DSA_get0_key(dsa, &pub_key, NULL);
    DSA_get0_pqg(dsa, &p, &q, &g);

    t = (BN_num_bytes(p) - 64) / 8;
    if (t > 8)
        return (DST_R_INVALIDPUBLICKEY);
    p_bytes = 64 + 8 * t;

    dnslen = 1 + (key->key_size * 3)/8 + ISC_SHA1_DIGESTLENGTH;
    if (r.length < (unsigned int) dnslen)
        return (ISC_R_NOSPACE);

    *r.base = t;
    isc_region_consume(&r, 1);

    BN_bn2bin_fixed(q, r.base, ISC_SHA1_DIGESTLENGTH);
    isc_region_consume(&r, ISC_SHA1_DIGESTLENGTH);
    BN_bn2bin_fixed(p, r.base, key->key_size/8);
    isc_region_consume(&r, p_bytes);
    BN_bn2bin_fixed(g, r.base, key->key_size/8);
    isc_region_consume(&r, p_bytes);
    BN_bn2bin_fixed(pub_key, r.base, key->key_size/8);
    isc_region_consume(&r, p_bytes);

    isc_buffer_add(data, dnslen);

    return (ISC_R_SUCCESS);
}

static isc_result_t
openssldsa_fromdns(dst_key_t *key, isc_buffer_t *data) {
    DSA *dsa;
    BIGNUM *pub_key, *p, *q, *g;
    isc_region_t r;
    unsigned int t, p_bytes;
    isc_mem_t *mctx = key->mctx;

    UNUSED(mctx);

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

    dsa = DSA_new();
    if (dsa == NULL)
        return (ISC_R_NOMEMORY);
    DSA_clear_flags(dsa, DSA_FLAG_CACHE_MONT_P);

    t = (unsigned int) *r.base;
    isc_region_consume(&r, 1);
    if (t > 8) {
        DSA_free(dsa);
        return (DST_R_INVALIDPUBLICKEY);
    }
    p_bytes = 64 + 8 * t;

    if (r.length < ISC_SHA1_DIGESTLENGTH + 3 * p_bytes) {
        DSA_free(dsa);
        return (DST_R_INVALIDPUBLICKEY);
    }

    q = BN_bin2bn(r.base, ISC_SHA1_DIGESTLENGTH, NULL);
    isc_region_consume(&r, ISC_SHA1_DIGESTLENGTH);

    p = BN_bin2bn(r.base, p_bytes, NULL);
    isc_region_consume(&r, p_bytes);

    g = BN_bin2bn(r.base, p_bytes, NULL);
    isc_region_consume(&r, p_bytes);

    pub_key = BN_bin2bn(r.base, p_bytes, NULL);
    isc_region_consume(&r, p_bytes);

    if (pub_key == NULL || p == NULL || q == NULL || g == NULL) {
        DSA_free(dsa);
        if (p != NULL) BN_free(p);
        if (q != NULL) BN_free(q);
        if (g != NULL) BN_free(g);
        return (ISC_R_NOMEMORY);
    }

    DSA_set0_key(dsa, pub_key, NULL);
    DSA_set0_pqg(dsa, p, q, g);

    key->key_size = p_bytes * 8;

    isc_buffer_forward(data, 1 + ISC_SHA1_DIGESTLENGTH + 3 * p_bytes);

    key->keydata.dsa = dsa;

    return (ISC_R_SUCCESS);
}


static isc_result_t
openssldsa_tofile(const dst_key_t *key, const char *directory) {
    int cnt = 0;
    DSA *dsa;
    const BIGNUM *pub_key = NULL, *priv_key = NULL;
    const BIGNUM *p = NULL, *q = NULL, *g = NULL;
    dst_private_t priv;
    unsigned char bufs[5][128];

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

    if (key->external) {
        priv.nelements = 0;
        return (dst__privstruct_writefile(key, &priv, directory));
    }

    dsa = key->keydata.dsa;

    DSA_get0_key(dsa, &pub_key, &priv_key);
    DSA_get0_pqg(dsa, &p, &q, &g);

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

    priv.elements[cnt].tag = TAG_DSA_SUBPRIME;
    priv.elements[cnt].length = BN_num_bytes(q);
    BN_bn2bin(q, bufs[cnt]);
    priv.elements[cnt].data = bufs[cnt];
    cnt++;

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

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

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

    priv.nelements = cnt;
    return (dst__privstruct_writefile(key, &priv, directory));
}

static isc_result_t
openssldsa_parse(dst_key_t *key, isc_lex_t *lexer, dst_key_t *pub) {
    dst_private_t priv;
    isc_result_t ret;
    int i;
    DSA *dsa = NULL;
    BIGNUM *pub_key = NULL, *priv_key = NULL;
    BIGNUM *p = NULL, *q = NULL, *g = NULL;
    isc_mem_t *mctx = key->mctx;
#define DST_RET(a) {ret = a; goto err;}

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

    if (key->external) {
        if (priv.nelements != 0)
            DST_RET(DST_R_INVALIDPRIVATEKEY);
        if (pub == NULL)
            DST_RET(DST_R_INVALIDPRIVATEKEY);
        key->keydata.pkey = pub->keydata.pkey;
        pub->keydata.pkey = NULL;
        key->key_size = pub->key_size;
        dst__privstruct_free(&priv, mctx);
        isc_safe_memwipe(&priv, sizeof(priv));
        return (ISC_R_SUCCESS);
    }

    dsa = DSA_new();
    if (dsa == NULL)
        DST_RET(ISC_R_NOMEMORY);
    DSA_clear_flags(dsa, DSA_FLAG_CACHE_MONT_P);
    key->keydata.dsa = dsa;

    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_DSA_PRIME:
                p = bn;
                break;
            case TAG_DSA_SUBPRIME:
                q = bn;
                break;
            case TAG_DSA_BASE:
                g = bn;
                break;
            case TAG_DSA_PRIVATE:
                priv_key = bn;
                break;
            case TAG_DSA_PUBLIC:
                pub_key = bn;
                break;
        }
    }
    dst__privstruct_free(&priv, mctx);
    isc_safe_memwipe(&priv, sizeof(priv));
    DSA_set0_key(dsa, pub_key, priv_key);
    DSA_set0_pqg(dsa, p, q, g);
    key->key_size = BN_num_bits(p);
    return (ISC_R_SUCCESS);

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

static dst_func_t openssldsa_functions = {
    openssldsa_createctx,
    NULL, /*%< createctx2 */
    openssldsa_destroyctx,
    openssldsa_adddata,
    openssldsa_sign,
    openssldsa_verify,
    NULL, /*%< verify2 */
    NULL, /*%< computesecret */
    openssldsa_compare,
    NULL, /*%< paramcompare */
    openssldsa_generate,
    openssldsa_isprivate,
    openssldsa_destroy,
    openssldsa_todns,
    openssldsa_fromdns,
    openssldsa_tofile,
    openssldsa_parse,
    NULL, /*%< cleanup */
    NULL, /*%< fromlabel */
    NULL, /*%< dump */
    NULL, /*%< restore */
};

isc_result_t
dst__openssldsa_init(dst_func_t **funcp) {
    REQUIRE(funcp != NULL);
    if (*funcp == NULL)
        *funcp = &openssldsa_functions;
    return (ISC_R_SUCCESS);
}
#endif /* !PK11_DSA_DISABLE */

#else /* OPENSSL */

#include <isc/util.h>

EMPTY_TRANSLATION_UNIT

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