lib/dns/dst_api.c

	dst_api.c revision d5c07393519277550540f0bd80779bca7f800b51
/*
 * Portions Copyright (C) 2004-2011  Internet Systems Consortium, Inc. ("ISC")
 * Portions Copyright (C) 1999-2003  Internet Software Consortium.
 *
 * 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.
 *
 * 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: dst_api.c,v 1.63 2011/08/18 23:46:34 tbox Exp $
 */

/*! \file */

#include <config.h>

#include <stdlib.h>
#include <time.h>

#include <isc/buffer.h>
#include <isc/dir.h>
#include <isc/entropy.h>
#include <isc/fsaccess.h>
#include <isc/hmacsha.h>
#include <isc/lex.h>
#include <isc/mem.h>
#include <isc/once.h>
#include <isc/platform.h>
#include <isc/print.h>
#include <isc/refcount.h>
#include <isc/random.h>
#include <isc/string.h>
#include <isc/time.h>
#include <isc/util.h>

#include <dns/fixedname.h>
#include <dns/keyvalues.h>
#include <dns/name.h>
#include <dns/rdata.h>
#include <dns/rdataclass.h>
#include <dns/ttl.h>
#include <dns/types.h>

#include <dst/result.h>

#include "dst_internal.h"

#define DST_AS_STR(t) ((t).value.as_textregion.base)

static dst_func_t *dst_t_func[DST_MAX_ALGS];
#ifdef BIND9
static isc_entropy_t *dst_entropy_pool = NULL;
#endif
static unsigned int dst_entropy_flags = 0;
static isc_boolean_t dst_initialized = ISC_FALSE;

void gss_log(int level, const char *fmt, ...) ISC_FORMAT_PRINTF(2, 3);

isc_mem_t *dst__memory_pool = NULL;

/*
 * Static functions.
 */
static dst_key_t *  get_key_struct(dns_name_t *name,
                       unsigned int alg,
                       unsigned int flags,
                       unsigned int protocol,
                       unsigned int bits,
                       dns_rdataclass_t rdclass,
                       dns_ttl_t ttl,
                       isc_mem_t *mctx);
static isc_result_t write_public_key(const dst_key_t *key, int type,
                     const char *directory);
static isc_result_t buildfilename(dns_name_t *name,
                      dns_keytag_t id,
                      unsigned int alg,
                      unsigned int type,
                      const char *directory,
                      isc_buffer_t *out);
static isc_result_t computeid(dst_key_t *key);
static isc_result_t frombuffer(dns_name_t *name,
                   unsigned int alg,
                   unsigned int flags,
                   unsigned int protocol,
                   dns_rdataclass_t rdclass,
                   isc_buffer_t *source,
                   isc_mem_t *mctx,
                   dst_key_t **keyp);

static isc_result_t algorithm_status(unsigned int alg);

static isc_result_t addsuffix(char *filename, int len,
                  const char *dirname, const char *ofilename,
                  const char *suffix);

#define RETERR(x)               \
    do {                    \
        result = (x);           \
        if (result != ISC_R_SUCCESS)    \
            goto out;       \
    } while (0)

#define CHECKALG(alg)               \
    do {                    \
        isc_result_t _r;        \
        _r = algorithm_status(alg); \
        if (_r != ISC_R_SUCCESS)    \
            return (_r);        \
    } while (0);                \

#if defined(OPENSSL) && defined(BIND9)
static void *
default_memalloc(void *arg, size_t size) {
    UNUSED(arg);
    if (size == 0U)
        size = 1;
    return (malloc(size));
}

static void
default_memfree(void *arg, void *ptr) {
    UNUSED(arg);
    free(ptr);
}
#endif

isc_result_t
dst_lib_init(isc_mem_t *mctx, isc_entropy_t *ectx, unsigned int eflags) {
    return (dst_lib_init2(mctx, ectx, NULL, eflags));
}

isc_result_t
dst_lib_init2(isc_mem_t *mctx, isc_entropy_t *ectx,
          const char *engine, unsigned int eflags) {
    isc_result_t result;

    REQUIRE(mctx != NULL);
#ifdef BIND9
    REQUIRE(ectx != NULL);
#else
    UNUSED(ectx);
#endif
    REQUIRE(dst_initialized == ISC_FALSE);

#ifndef OPENSSL
    UNUSED(engine);
#endif

    dst__memory_pool = NULL;

#if defined(OPENSSL) && defined(BIND9)
    UNUSED(mctx);
    /*
     * When using --with-openssl, there seems to be no good way of not
     * leaking memory due to the openssl error handling mechanism.
     * Avoid assertions by using a local memory context and not checking
     * for leaks on exit.  Note: as there are leaks we cannot use
     * ISC_MEMFLAG_INTERNAL as it will free up memory still being used
     * by libcrypto.
     */
    result = isc_mem_createx2(0, 0, default_memalloc, default_memfree,
                  NULL, &dst__memory_pool, 0);
    if (result != ISC_R_SUCCESS)
        return (result);
    isc_mem_setname(dst__memory_pool, "dst", NULL);
#ifndef OPENSSL_LEAKS
    isc_mem_setdestroycheck(dst__memory_pool, ISC_FALSE);
#endif
#else
    isc_mem_attach(mctx, &dst__memory_pool);
#endif
#ifdef BIND9
    isc_entropy_attach(ectx, &dst_entropy_pool);
#endif
    dst_entropy_flags = eflags;

    dst_result_register();

    memset(dst_t_func, 0, sizeof(dst_t_func));
    RETERR(dst__hmacmd5_init(&dst_t_func[DST_ALG_HMACMD5]));
    RETERR(dst__hmacsha1_init(&dst_t_func[DST_ALG_HMACSHA1]));
    RETERR(dst__hmacsha224_init(&dst_t_func[DST_ALG_HMACSHA224]));
    RETERR(dst__hmacsha256_init(&dst_t_func[DST_ALG_HMACSHA256]));
    RETERR(dst__hmacsha384_init(&dst_t_func[DST_ALG_HMACSHA384]));
    RETERR(dst__hmacsha512_init(&dst_t_func[DST_ALG_HMACSHA512]));
#ifdef OPENSSL
    RETERR(dst__openssl_init(engine));
    RETERR(dst__opensslrsa_init(&dst_t_func[DST_ALG_RSAMD5],
                    DST_ALG_RSAMD5));
    RETERR(dst__opensslrsa_init(&dst_t_func[DST_ALG_RSASHA1],
                    DST_ALG_RSASHA1));
    RETERR(dst__opensslrsa_init(&dst_t_func[DST_ALG_NSEC3RSASHA1],
                    DST_ALG_NSEC3RSASHA1));
    RETERR(dst__opensslrsa_init(&dst_t_func[DST_ALG_RSASHA256],
                    DST_ALG_RSASHA256));
    RETERR(dst__opensslrsa_init(&dst_t_func[DST_ALG_RSASHA512],
                    DST_ALG_RSASHA512));
#ifdef HAVE_OPENSSL_DSA
    RETERR(dst__openssldsa_init(&dst_t_func[DST_ALG_DSA]));
    RETERR(dst__openssldsa_init(&dst_t_func[DST_ALG_NSEC3DSA]));
#endif
    RETERR(dst__openssldh_init(&dst_t_func[DST_ALG_DH]));
#ifdef HAVE_OPENSSL_GOST
    RETERR(dst__opensslgost_init(&dst_t_func[DST_ALG_ECCGOST]));
#endif
#endif /* OPENSSL */
#ifdef GSSAPI
    RETERR(dst__gssapi_init(&dst_t_func[DST_ALG_GSSAPI]));
#endif
    dst_initialized = ISC_TRUE;
    return (ISC_R_SUCCESS);

 out:
    /* avoid immediate crash! */
    dst_initialized = ISC_TRUE;
    dst_lib_destroy();
    return (result);
}

void
dst_lib_destroy(void) {
    int i;
    RUNTIME_CHECK(dst_initialized == ISC_TRUE);
    dst_initialized = ISC_FALSE;

    for (i = 0; i < DST_MAX_ALGS; i++)
        if (dst_t_func[i] != NULL && dst_t_func[i]->cleanup != NULL)
            dst_t_func[i]->cleanup();
#ifdef OPENSSL
    dst__openssl_destroy();
#endif
    if (dst__memory_pool != NULL)
        isc_mem_detach(&dst__memory_pool);
#ifdef BIND9
    if (dst_entropy_pool != NULL)
        isc_entropy_detach(&dst_entropy_pool);
#endif
}

isc_boolean_t
dst_algorithm_supported(unsigned int alg) {
    REQUIRE(dst_initialized == ISC_TRUE);

    if (alg >= DST_MAX_ALGS || dst_t_func[alg] == NULL)
        return (ISC_FALSE);
    return (ISC_TRUE);
}

isc_result_t
dst_context_create(dst_key_t *key, isc_mem_t *mctx, dst_context_t **dctxp) {
    dst_context_t *dctx;
    isc_result_t result;

    REQUIRE(dst_initialized == ISC_TRUE);
    REQUIRE(VALID_KEY(key));
    REQUIRE(mctx != NULL);
    REQUIRE(dctxp != NULL && *dctxp == NULL);

    if (key->func->createctx == NULL)
        return (DST_R_UNSUPPORTEDALG);
    if (key->keydata.generic == NULL)
        return (DST_R_NULLKEY);

    dctx = isc_mem_get(mctx, sizeof(dst_context_t));
    if (dctx == NULL)
        return (ISC_R_NOMEMORY);
    dctx->key = key;
    dctx->mctx = mctx;
    result = key->func->createctx(key, dctx);
    if (result != ISC_R_SUCCESS) {
        isc_mem_put(mctx, dctx, sizeof(dst_context_t));
        return (result);
    }
    dctx->magic = CTX_MAGIC;
    *dctxp = dctx;
    return (ISC_R_SUCCESS);
}

void
dst_context_destroy(dst_context_t **dctxp) {
    dst_context_t *dctx;

    REQUIRE(dctxp != NULL && VALID_CTX(*dctxp));

    dctx = *dctxp;
    INSIST(dctx->key->func->destroyctx != NULL);
    dctx->key->func->destroyctx(dctx);
    dctx->magic = 0;
    isc_mem_put(dctx->mctx, dctx, sizeof(dst_context_t));
    *dctxp = NULL;
}

isc_result_t
dst_context_adddata(dst_context_t *dctx, const isc_region_t *data) {
    REQUIRE(VALID_CTX(dctx));
    REQUIRE(data != NULL);
    INSIST(dctx->key->func->adddata != NULL);

    return (dctx->key->func->adddata(dctx, data));
}

isc_result_t
dst_context_sign(dst_context_t *dctx, isc_buffer_t *sig) {
    dst_key_t *key;

    REQUIRE(VALID_CTX(dctx));
    REQUIRE(sig != NULL);

    key = dctx->key;
    CHECKALG(key->key_alg);
    if (key->keydata.generic == NULL)
        return (DST_R_NULLKEY);

    if (key->func->sign == NULL)
        return (DST_R_NOTPRIVATEKEY);
    if (key->func->isprivate == NULL ||
        key->func->isprivate(key) == ISC_FALSE)
        return (DST_R_NOTPRIVATEKEY);

    return (key->func->sign(dctx, sig));
}

isc_result_t
dst_context_verify(dst_context_t *dctx, isc_region_t *sig) {
    REQUIRE(VALID_CTX(dctx));
    REQUIRE(sig != NULL);

    CHECKALG(dctx->key->key_alg);
    if (dctx->key->keydata.generic == NULL)
        return (DST_R_NULLKEY);
    if (dctx->key->func->verify == NULL)
        return (DST_R_NOTPUBLICKEY);

    return (dctx->key->func->verify(dctx, sig));
}

isc_result_t
dst_key_computesecret(const dst_key_t *pub, const dst_key_t *priv,
              isc_buffer_t *secret)
{
    REQUIRE(dst_initialized == ISC_TRUE);
    REQUIRE(VALID_KEY(pub) && VALID_KEY(priv));
    REQUIRE(secret != NULL);

    CHECKALG(pub->key_alg);
    CHECKALG(priv->key_alg);

    if (pub->keydata.generic == NULL || priv->keydata.generic == NULL)
        return (DST_R_NULLKEY);

    if (pub->key_alg != priv->key_alg ||
        pub->func->computesecret == NULL ||
        priv->func->computesecret == NULL)
        return (DST_R_KEYCANNOTCOMPUTESECRET);

    if (dst_key_isprivate(priv) == ISC_FALSE)
        return (DST_R_NOTPRIVATEKEY);

    return (pub->func->computesecret(pub, priv, secret));
}

isc_result_t
dst_key_tofile(const dst_key_t *key, int type, const char *directory) {
    isc_result_t ret = ISC_R_SUCCESS;

    REQUIRE(dst_initialized == ISC_TRUE);
    REQUIRE(VALID_KEY(key));
    REQUIRE((type & (DST_TYPE_PRIVATE | DST_TYPE_PUBLIC)) != 0);

    CHECKALG(key->key_alg);

    if (key->func->tofile == NULL)
        return (DST_R_UNSUPPORTEDALG);

    if (type & DST_TYPE_PUBLIC) {
        ret = write_public_key(key, type, directory);
        if (ret != ISC_R_SUCCESS)
            return (ret);
    }

    if ((type & DST_TYPE_PRIVATE) &&
        (key->key_flags & DNS_KEYFLAG_TYPEMASK) != DNS_KEYTYPE_NOKEY)
        return (key->func->tofile(key, directory));
    else
        return (ISC_R_SUCCESS);
}

isc_result_t
dst_key_fromfile(dns_name_t *name, dns_keytag_t id,
         unsigned int alg, int type, const char *directory,
         isc_mem_t *mctx, dst_key_t **keyp)
{
    char filename[ISC_DIR_NAMEMAX];
    isc_buffer_t b;
    dst_key_t *key;
    isc_result_t result;

    REQUIRE(dst_initialized == ISC_TRUE);
    REQUIRE(dns_name_isabsolute(name));
    REQUIRE((type & (DST_TYPE_PRIVATE | DST_TYPE_PUBLIC)) != 0);
    REQUIRE(mctx != NULL);
    REQUIRE(keyp != NULL && *keyp == NULL);

    CHECKALG(alg);

    isc_buffer_init(&b, filename, sizeof(filename));
    result = buildfilename(name, id, alg, type, directory, &b);
    if (result != ISC_R_SUCCESS)
        return (result);

    key = NULL;
    result = dst_key_fromnamedfile(filename, NULL, type, mctx, &key);
    if (result != ISC_R_SUCCESS)
        return (result);

    result = computeid(key);
    if (result != ISC_R_SUCCESS) {
        dst_key_free(&key);
        return (result);
    }

    if (!dns_name_equal(name, key->key_name) || id != key->key_id ||
        alg != key->key_alg) {
        dst_key_free(&key);
        return (DST_R_INVALIDPRIVATEKEY);
    }
    key->key_id = id;

    *keyp = key;
    return (ISC_R_SUCCESS);
}

isc_result_t
dst_key_fromnamedfile(const char *filename, const char *dirname,
              int type, isc_mem_t *mctx, dst_key_t **keyp)
{
    isc_result_t result;
    dst_key_t *pubkey = NULL, *key = NULL;
    char *newfilename = NULL;
    int newfilenamelen = 0;
    isc_lex_t *lex = NULL;

    REQUIRE(dst_initialized == ISC_TRUE);
    REQUIRE(filename != NULL);
    REQUIRE((type & (DST_TYPE_PRIVATE | DST_TYPE_PUBLIC)) != 0);
    REQUIRE(mctx != NULL);
    REQUIRE(keyp != NULL && *keyp == NULL);

    /* If an absolute path is specified, don't use the key directory */
#ifndef WIN32
    if (filename[0] == '/')
        dirname = NULL;
#else /* WIN32 */
    if (filename[0] == '/' || filename[0] == '\\')
        dirname = NULL;
#endif

    newfilenamelen = strlen(filename) + 5;
    if (dirname != NULL)
        newfilenamelen += strlen(dirname) + 1;
    newfilename = isc_mem_get(mctx, newfilenamelen);
    if (newfilename == NULL)
        return (ISC_R_NOMEMORY);
    result = addsuffix(newfilename, newfilenamelen,
               dirname, filename, ".key");
    INSIST(result == ISC_R_SUCCESS);

    result = dst_key_read_public(newfilename, type, mctx, &pubkey);
    isc_mem_put(mctx, newfilename, newfilenamelen);
    newfilename = NULL;
    if (result != ISC_R_SUCCESS)
        return (result);

    if ((type & (DST_TYPE_PRIVATE | DST_TYPE_PUBLIC)) == DST_TYPE_PUBLIC ||
        (pubkey->key_flags & DNS_KEYFLAG_TYPEMASK) == DNS_KEYTYPE_NOKEY) {
        result = computeid(pubkey);
        if (result != ISC_R_SUCCESS) {
            dst_key_free(&pubkey);
            return (result);
        }

        *keyp = pubkey;
        return (ISC_R_SUCCESS);
    }

    result = algorithm_status(pubkey->key_alg);
    if (result != ISC_R_SUCCESS) {
        dst_key_free(&pubkey);
        return (result);
    }

    key = get_key_struct(pubkey->key_name, pubkey->key_alg,
                 pubkey->key_flags, pubkey->key_proto, 0,
                 pubkey->key_class, pubkey->key_ttl, mctx);
    if (key == NULL) {
        dst_key_free(&pubkey);
        return (ISC_R_NOMEMORY);
    }

    if (key->func->parse == NULL)
        RETERR(DST_R_UNSUPPORTEDALG);

    newfilenamelen = strlen(filename) + 9;
    if (dirname != NULL)
        newfilenamelen += strlen(dirname) + 1;
    newfilename = isc_mem_get(mctx, newfilenamelen);
    if (newfilename == NULL)
        RETERR(ISC_R_NOMEMORY);
    result = addsuffix(newfilename, newfilenamelen,
               dirname, filename, ".private");
    INSIST(result == ISC_R_SUCCESS);

    RETERR(isc_lex_create(mctx, 1500, &lex));
    RETERR(isc_lex_openfile(lex, newfilename));
    isc_mem_put(mctx, newfilename, newfilenamelen);

    RETERR(key->func->parse(key, lex, pubkey));
    isc_lex_destroy(&lex);

    RETERR(computeid(key));

    if (pubkey->key_id != key->key_id)
        RETERR(DST_R_INVALIDPRIVATEKEY);
    dst_key_free(&pubkey);

    *keyp = key;
    return (ISC_R_SUCCESS);

 out:
    if (pubkey != NULL)
        dst_key_free(&pubkey);
    if (newfilename != NULL)
        isc_mem_put(mctx, newfilename, newfilenamelen);
    if (lex != NULL)
        isc_lex_destroy(&lex);
    dst_key_free(&key);
    return (result);
}

isc_result_t
dst_key_todns(const dst_key_t *key, isc_buffer_t *target) {
    REQUIRE(dst_initialized == ISC_TRUE);
    REQUIRE(VALID_KEY(key));
    REQUIRE(target != NULL);

    CHECKALG(key->key_alg);

    if (key->func->todns == NULL)
        return (DST_R_UNSUPPORTEDALG);

    if (isc_buffer_availablelength(target) < 4)
        return (ISC_R_NOSPACE);
    isc_buffer_putuint16(target, (isc_uint16_t)(key->key_flags & 0xffff));
    isc_buffer_putuint8(target, (isc_uint8_t)key->key_proto);
    isc_buffer_putuint8(target, (isc_uint8_t)key->key_alg);

    if (key->key_flags & DNS_KEYFLAG_EXTENDED) {
        if (isc_buffer_availablelength(target) < 2)
            return (ISC_R_NOSPACE);
        isc_buffer_putuint16(target,
                     (isc_uint16_t)((key->key_flags >> 16)
                            & 0xffff));
    }

    if (key->keydata.generic == NULL) /*%< NULL KEY */
        return (ISC_R_SUCCESS);

    return (key->func->todns(key, target));
}

isc_result_t
dst_key_fromdns(dns_name_t *name, dns_rdataclass_t rdclass,
        isc_buffer_t *source, isc_mem_t *mctx, dst_key_t **keyp)
{
    isc_uint8_t alg, proto;
    isc_uint32_t flags, extflags;
    dst_key_t *key = NULL;
    dns_keytag_t id;
    isc_region_t r;
    isc_result_t result;

    REQUIRE(dst_initialized);

    isc_buffer_remainingregion(source, &r);

    if (isc_buffer_remaininglength(source) < 4)
        return (DST_R_INVALIDPUBLICKEY);
    flags = isc_buffer_getuint16(source);
    proto = isc_buffer_getuint8(source);
    alg = isc_buffer_getuint8(source);

    id = dst_region_computeid(&r, alg);

    if (flags & DNS_KEYFLAG_EXTENDED) {
        if (isc_buffer_remaininglength(source) < 2)
            return (DST_R_INVALIDPUBLICKEY);
        extflags = isc_buffer_getuint16(source);
        flags |= (extflags << 16);
    }

    result = frombuffer(name, alg, flags, proto, rdclass, source,
                mctx, &key);
    if (result != ISC_R_SUCCESS)
        return (result);
    key->key_id = id;

    *keyp = key;
    return (ISC_R_SUCCESS);
}

isc_result_t
dst_key_frombuffer(dns_name_t *name, unsigned int alg,
           unsigned int flags, unsigned int protocol,
           dns_rdataclass_t rdclass,
           isc_buffer_t *source, isc_mem_t *mctx, dst_key_t **keyp)
{
    dst_key_t *key = NULL;
    isc_result_t result;

    REQUIRE(dst_initialized);

    result = frombuffer(name, alg, flags, protocol, rdclass, source,
                mctx, &key);
    if (result != ISC_R_SUCCESS)
        return (result);

    result = computeid(key);
    if (result != ISC_R_SUCCESS) {
        dst_key_free(&key);
        return (result);
    }

    *keyp = key;
    return (ISC_R_SUCCESS);
}

isc_result_t
dst_key_tobuffer(const dst_key_t *key, isc_buffer_t *target) {
    REQUIRE(dst_initialized == ISC_TRUE);
    REQUIRE(VALID_KEY(key));
    REQUIRE(target != NULL);

    CHECKALG(key->key_alg);

    if (key->func->todns == NULL)
        return (DST_R_UNSUPPORTEDALG);

    return (key->func->todns(key, target));
}

isc_result_t
dst_key_privatefrombuffer(dst_key_t *key, isc_buffer_t *buffer) {
    isc_lex_t *lex = NULL;
    isc_result_t result = ISC_R_SUCCESS;

    REQUIRE(dst_initialized == ISC_TRUE);
    REQUIRE(VALID_KEY(key));
    REQUIRE(!dst_key_isprivate(key));
    REQUIRE(buffer != NULL);

    if (key->func->parse == NULL)
        RETERR(DST_R_UNSUPPORTEDALG);

    RETERR(isc_lex_create(key->mctx, 1500, &lex));
    RETERR(isc_lex_openbuffer(lex, buffer));
    RETERR(key->func->parse(key, lex, NULL));
 out:
    if (lex != NULL)
        isc_lex_destroy(&lex);
    return (result);
}

gss_ctx_id_t
dst_key_getgssctx(const dst_key_t *key)
{
    REQUIRE(key != NULL);

    return (key->keydata.gssctx);
}

isc_result_t
dst_key_fromgssapi(dns_name_t *name, gss_ctx_id_t gssctx, isc_mem_t *mctx,
           dst_key_t **keyp, isc_region_t *intoken)
{
    dst_key_t *key;
    isc_result_t result;

    REQUIRE(gssctx != NULL);
    REQUIRE(keyp != NULL && *keyp == NULL);

    key = get_key_struct(name, DST_ALG_GSSAPI, 0, DNS_KEYPROTO_DNSSEC,
                 0, dns_rdataclass_in, 0, mctx);
    if (key == NULL)
        return (ISC_R_NOMEMORY);

    if (intoken != NULL) {
        /*
         * Keep the token for use by external ssu rules. They may need
         * to examine the PAC in the kerberos ticket.
         */
        RETERR(isc_buffer_allocate(key->mctx, &key->key_tkeytoken,
               intoken->length));
        RETERR(isc_buffer_copyregion(key->key_tkeytoken, intoken));
    }

    key->keydata.gssctx = gssctx;
    *keyp = key;
    result = ISC_R_SUCCESS;
out:
    return result;
}

isc_result_t
dst_key_fromlabel(dns_name_t *name, int alg, unsigned int flags,
          unsigned int protocol, dns_rdataclass_t rdclass,
          const char *engine, const char *label, const char *pin,
          isc_mem_t *mctx, dst_key_t **keyp)
{
    dst_key_t *key;
    isc_result_t result;

    REQUIRE(dst_initialized == ISC_TRUE);
    REQUIRE(dns_name_isabsolute(name));
    REQUIRE(mctx != NULL);
    REQUIRE(keyp != NULL && *keyp == NULL);
    REQUIRE(label != NULL);

    CHECKALG(alg);

    key = get_key_struct(name, alg, flags, protocol, 0, rdclass, 0, mctx);
    if (key == NULL)
        return (ISC_R_NOMEMORY);

    if (key->func->fromlabel == NULL) {
        dst_key_free(&key);
        return (DST_R_UNSUPPORTEDALG);
    }

    result = key->func->fromlabel(key, engine, label, pin);
    if (result != ISC_R_SUCCESS) {
        dst_key_free(&key);
        return (result);
    }

    result = computeid(key);
    if (result != ISC_R_SUCCESS) {
        dst_key_free(&key);
        return (result);
    }

    *keyp = key;
    return (ISC_R_SUCCESS);
}

isc_result_t
dst_key_generate(dns_name_t *name, unsigned int alg,
         unsigned int bits, unsigned int param,
         unsigned int flags, unsigned int protocol,
         dns_rdataclass_t rdclass,
         isc_mem_t *mctx, dst_key_t **keyp)
{
    return (dst_key_generate2(name, alg, bits, param, flags, protocol,
                  rdclass, mctx, keyp, NULL));
}

isc_result_t
dst_key_generate2(dns_name_t *name, unsigned int alg,
          unsigned int bits, unsigned int param,
          unsigned int flags, unsigned int protocol,
          dns_rdataclass_t rdclass,
          isc_mem_t *mctx, dst_key_t **keyp,
          void (*callback)(int))
{
    dst_key_t *key;
    isc_result_t ret;

    REQUIRE(dst_initialized == ISC_TRUE);
    REQUIRE(dns_name_isabsolute(name));
    REQUIRE(mctx != NULL);
    REQUIRE(keyp != NULL && *keyp == NULL);

    CHECKALG(alg);

    key = get_key_struct(name, alg, flags, protocol, bits,
                 rdclass, 0, mctx);
    if (key == NULL)
        return (ISC_R_NOMEMORY);

    if (bits == 0) { /*%< NULL KEY */
        key->key_flags |= DNS_KEYTYPE_NOKEY;
        *keyp = key;
        return (ISC_R_SUCCESS);
    }

    if (key->func->generate == NULL) {
        dst_key_free(&key);
        return (DST_R_UNSUPPORTEDALG);
    }

    ret = key->func->generate(key, param, callback);
    if (ret != ISC_R_SUCCESS) {
        dst_key_free(&key);
        return (ret);
    }

    ret = computeid(key);
    if (ret != ISC_R_SUCCESS) {
        dst_key_free(&key);
        return (ret);
    }

    *keyp = key;
    return (ISC_R_SUCCESS);
}

isc_result_t
dst_key_getnum(const dst_key_t *key, int type, isc_uint32_t *valuep)
{
    REQUIRE(VALID_KEY(key));
    REQUIRE(valuep != NULL);
    REQUIRE(type <= DST_MAX_NUMERIC);
    if (!key->numset[type])
        return (ISC_R_NOTFOUND);
    *valuep = key->nums[type];
    return (ISC_R_SUCCESS);
}

void
dst_key_setnum(dst_key_t *key, int type, isc_uint32_t value)
{
    REQUIRE(VALID_KEY(key));
    REQUIRE(type <= DST_MAX_NUMERIC);
    key->nums[type] = value;
    key->numset[type] = ISC_TRUE;
}

void
dst_key_unsetnum(dst_key_t *key, int type)
{
    REQUIRE(VALID_KEY(key));
    REQUIRE(type <= DST_MAX_NUMERIC);
    key->numset[type] = ISC_FALSE;
}

isc_result_t
dst_key_gettime(const dst_key_t *key, int type, isc_stdtime_t *timep) {
    REQUIRE(VALID_KEY(key));
    REQUIRE(timep != NULL);
    REQUIRE(type <= DST_MAX_TIMES);
    if (!key->timeset[type])
        return (ISC_R_NOTFOUND);
    *timep = key->times[type];
    return (ISC_R_SUCCESS);
}

void
dst_key_settime(dst_key_t *key, int type, isc_stdtime_t when) {
    REQUIRE(VALID_KEY(key));
    REQUIRE(type <= DST_MAX_TIMES);
    key->times[type] = when;
    key->timeset[type] = ISC_TRUE;
}

void
dst_key_unsettime(dst_key_t *key, int type) {
    REQUIRE(VALID_KEY(key));
    REQUIRE(type <= DST_MAX_TIMES);
    key->timeset[type] = ISC_FALSE;
}

isc_result_t
dst_key_getprivateformat(const dst_key_t *key, int *majorp, int *minorp) {
    REQUIRE(VALID_KEY(key));
    REQUIRE(majorp != NULL);
    REQUIRE(minorp != NULL);
    *majorp = key->fmt_major;
    *minorp = key->fmt_minor;
    return (ISC_R_SUCCESS);
}

void
dst_key_setprivateformat(dst_key_t *key, int major, int minor) {
    REQUIRE(VALID_KEY(key));
    key->fmt_major = major;
    key->fmt_minor = minor;
}

static isc_boolean_t
comparekeys(const dst_key_t *key1, const dst_key_t *key2,
        isc_boolean_t match_revoked_key,
        isc_boolean_t (*compare)(const dst_key_t *key1,
                     const dst_key_t *key2))
{
    REQUIRE(dst_initialized == ISC_TRUE);
    REQUIRE(VALID_KEY(key1));
    REQUIRE(VALID_KEY(key2));

    if (key1 == key2)
        return (ISC_TRUE);

    if (key1 == NULL || key2 == NULL)
        return (ISC_FALSE);

    if (key1->key_alg != key2->key_alg)
        return (ISC_FALSE);

    /*
     * For all algorithms except RSAMD5, revoking the key
     * changes the key ID, increasing it by 128.  If we want to
     * be able to find matching keys even if one of them is the
     * revoked version of the other one, then we need to check
     * for that possibility.
     */
    if (key1->key_id != key2->key_id) {
        if (!match_revoked_key)
            return (ISC_FALSE);
        if (key1->key_alg == DST_ALG_RSAMD5)
            return (ISC_FALSE);
        if ((key1->key_flags & DNS_KEYFLAG_REVOKE) ==
            (key2->key_flags & DNS_KEYFLAG_REVOKE))
            return (ISC_FALSE);
        if ((key1->key_flags & DNS_KEYFLAG_REVOKE) != 0 &&
            key1->key_id != ((key2->key_id + 128) & 0xffff))
            return (ISC_FALSE);
        if ((key2->key_flags & DNS_KEYFLAG_REVOKE) != 0 &&
            key2->key_id != ((key1->key_id + 128) & 0xffff))
            return (ISC_FALSE);
    }

    if (compare != NULL)
        return (compare(key1, key2));
    else
        return (ISC_FALSE);
}


/*
 * Compares only the public portion of two keys, by converting them
 * both to wire format and comparing the results.
 */
static isc_boolean_t
pub_compare(const dst_key_t *key1, const dst_key_t *key2) {
    isc_result_t result;
    unsigned char buf1[DST_KEY_MAXSIZE], buf2[DST_KEY_MAXSIZE];
    isc_buffer_t b1, b2;
    isc_region_t r1, r2;

    isc_buffer_init(&b1, buf1, sizeof(buf1));
    result = dst_key_todns(key1, &b1);
    if (result != ISC_R_SUCCESS)
        return (ISC_FALSE);
    /* Zero out flags. */
    buf1[0] = buf1[1] = 0;
    if ((key1->key_flags & DNS_KEYFLAG_EXTENDED) != 0)
        isc_buffer_subtract(&b1, 2);

    isc_buffer_init(&b2, buf2, sizeof(buf2));
    result = dst_key_todns(key2, &b2);
    if (result != ISC_R_SUCCESS)
        return (ISC_FALSE);
    /* Zero out flags. */
    buf2[0] = buf2[1] = 0;
    if ((key2->key_flags & DNS_KEYFLAG_EXTENDED) != 0)
        isc_buffer_subtract(&b2, 2);

    isc_buffer_usedregion(&b1, &r1);
    /* Remove extended flags. */
    if ((key1->key_flags & DNS_KEYFLAG_EXTENDED) != 0) {
        memmove(&buf1[4], &buf1[6], r1.length - 6);
        r1.length -= 2;
    }

    isc_buffer_usedregion(&b2, &r2);
    /* Remove extended flags. */
    if ((key2->key_flags & DNS_KEYFLAG_EXTENDED) != 0) {
        memmove(&buf2[4], &buf2[6], r2.length - 6);
        r2.length -= 2;
    }
    return (ISC_TF(isc_region_compare(&r1, &r2) == 0));
}

isc_boolean_t
dst_key_compare(const dst_key_t *key1, const dst_key_t *key2) {
    return (comparekeys(key1, key2, ISC_FALSE, key1->func->compare));
}

isc_boolean_t
dst_key_pubcompare(const dst_key_t *key1, const dst_key_t *key2,
           isc_boolean_t match_revoked_key)
{
    return (comparekeys(key1, key2, match_revoked_key, pub_compare));
}


isc_boolean_t
dst_key_paramcompare(const dst_key_t *key1, const dst_key_t *key2) {
    REQUIRE(dst_initialized == ISC_TRUE);
    REQUIRE(VALID_KEY(key1));
    REQUIRE(VALID_KEY(key2));

    if (key1 == key2)
        return (ISC_TRUE);
    if (key1 == NULL || key2 == NULL)
        return (ISC_FALSE);
    if (key1->key_alg == key2->key_alg &&
        key1->func->paramcompare != NULL &&
        key1->func->paramcompare(key1, key2) == ISC_TRUE)
        return (ISC_TRUE);
    else
        return (ISC_FALSE);
}

void
dst_key_attach(dst_key_t *source, dst_key_t **target) {

    REQUIRE(dst_initialized == ISC_TRUE);
    REQUIRE(target != NULL && *target == NULL);
    REQUIRE(VALID_KEY(source));

    isc_refcount_increment(&source->refs, NULL);
    *target = source;
}

void
dst_key_free(dst_key_t **keyp) {
    isc_mem_t *mctx;
    dst_key_t *key;
    unsigned int refs;

    REQUIRE(dst_initialized == ISC_TRUE);
    REQUIRE(keyp != NULL && VALID_KEY(*keyp));

    key = *keyp;
    mctx = key->mctx;

    isc_refcount_decrement(&key->refs, &refs);
    if (refs != 0)
        return;

    isc_refcount_destroy(&key->refs);
    if (key->keydata.generic != NULL) {
        INSIST(key->func->destroy != NULL);
        key->func->destroy(key);
    }
    if (key->engine != NULL)
        isc_mem_free(mctx, key->engine);
    if (key->label != NULL)
        isc_mem_free(mctx, key->label);
    dns_name_free(key->key_name, mctx);
    isc_mem_put(mctx, key->key_name, sizeof(dns_name_t));
    if (key->key_tkeytoken) {
        isc_buffer_free(&key->key_tkeytoken);
    }
    memset(key, 0, sizeof(dst_key_t));
    isc_mem_put(mctx, key, sizeof(dst_key_t));
    *keyp = NULL;
}

isc_boolean_t
dst_key_isprivate(const dst_key_t *key) {
    REQUIRE(VALID_KEY(key));
    INSIST(key->func->isprivate != NULL);
    return (key->func->isprivate(key));
}

isc_result_t
dst_key_buildfilename(const dst_key_t *key, int type,
              const char *directory, isc_buffer_t *out) {

    REQUIRE(VALID_KEY(key));
    REQUIRE(type == DST_TYPE_PRIVATE || type == DST_TYPE_PUBLIC ||
        type == 0);

    return (buildfilename(key->key_name, key->key_id, key->key_alg,
                  type, directory, out));
}

isc_result_t
dst_key_sigsize(const dst_key_t *key, unsigned int *n) {
    REQUIRE(dst_initialized == ISC_TRUE);
    REQUIRE(VALID_KEY(key));
    REQUIRE(n != NULL);

    /* XXXVIX this switch statement is too sparse to gen a jump table. */
    switch (key->key_alg) {
    case DST_ALG_RSAMD5:
    case DST_ALG_RSASHA1:
    case DST_ALG_NSEC3RSASHA1:
    case DST_ALG_RSASHA256:
    case DST_ALG_RSASHA512:
        *n = (key->key_size + 7) / 8;
        break;
    case DST_ALG_DSA:
    case DST_ALG_NSEC3DSA:
        *n = DNS_SIG_DSASIGSIZE;
        break;
    case DST_ALG_ECCGOST:
        *n = DNS_SIG_GOSTSIGSIZE;
        break;
    case DST_ALG_HMACMD5:
        *n = 16;
        break;
    case DST_ALG_HMACSHA1:
        *n = ISC_SHA1_DIGESTLENGTH;
        break;
    case DST_ALG_HMACSHA224:
        *n = ISC_SHA224_DIGESTLENGTH;
        break;
    case DST_ALG_HMACSHA256:
        *n = ISC_SHA256_DIGESTLENGTH;
        break;
    case DST_ALG_HMACSHA384:
        *n = ISC_SHA384_DIGESTLENGTH;
        break;
    case DST_ALG_HMACSHA512:
        *n = ISC_SHA512_DIGESTLENGTH;
        break;
    case DST_ALG_GSSAPI:
        *n = 128; /*%< XXX */
        break;
    case DST_ALG_DH:
    default:
        return (DST_R_UNSUPPORTEDALG);
    }
    return (ISC_R_SUCCESS);
}

isc_result_t
dst_key_secretsize(const dst_key_t *key, unsigned int *n) {
    REQUIRE(dst_initialized == ISC_TRUE);
    REQUIRE(VALID_KEY(key));
    REQUIRE(n != NULL);

    if (key->key_alg == DST_ALG_DH)
        *n = (key->key_size + 7) / 8;
    else
        return (DST_R_UNSUPPORTEDALG);
    return (ISC_R_SUCCESS);
}

/*%
 * Set the flags on a key, then recompute the key ID
 */
isc_result_t
dst_key_setflags(dst_key_t *key, isc_uint32_t flags) {
    REQUIRE(VALID_KEY(key));
    key->key_flags = flags;
    return (computeid(key));
}

void
dst_key_format(const dst_key_t *key, char *cp, unsigned int size) {
    char namestr[DNS_NAME_FORMATSIZE];
    char algstr[DNS_NAME_FORMATSIZE];

    dns_name_format(dst_key_name(key), namestr, sizeof(namestr));
    dns_secalg_format((dns_secalg_t) dst_key_alg(key), algstr,
              sizeof(algstr));
    snprintf(cp, size, "%s/%s/%d", namestr, algstr, dst_key_id(key));
}

isc_result_t
dst_key_dump(dst_key_t *key, isc_mem_t *mctx, char **buffer, int *length) {

    REQUIRE(buffer != NULL && *buffer == NULL);
    REQUIRE(length != NULL && *length == 0);
    REQUIRE(VALID_KEY(key));

    if (key->func->isprivate == NULL)
        return (ISC_R_NOTIMPLEMENTED);
    return (key->func->dump(key, mctx, buffer, length));
}

isc_result_t
dst_key_restore(dns_name_t *name, unsigned int alg, unsigned int flags,
        unsigned int protocol, dns_rdataclass_t rdclass,
        isc_mem_t *mctx, const char *keystr, dst_key_t **keyp)
{
    isc_result_t result;
    dst_key_t *key;

    REQUIRE(dst_initialized == ISC_TRUE);
    REQUIRE(keyp != NULL && *keyp == NULL);

    if (alg >= DST_MAX_ALGS || dst_t_func[alg] == NULL)
        return (DST_R_UNSUPPORTEDALG);

    if (dst_t_func[alg]->restore == NULL)
        return (ISC_R_NOTIMPLEMENTED);

    key = get_key_struct(name, alg, flags, protocol, 0, rdclass, 0, mctx);
    if (key == NULL)
        return (ISC_R_NOMEMORY);

    result = (dst_t_func[alg]->restore)(key, keystr);
    if (result == ISC_R_SUCCESS)
        *keyp = key;
    else
        dst_key_free(&key);

    return (result);
}

/***
 *** Static methods
 ***/

/*%
 * Allocates a key structure and fills in some of the fields.
 */
static dst_key_t *
get_key_struct(dns_name_t *name, unsigned int alg,
           unsigned int flags, unsigned int protocol,
           unsigned int bits, dns_rdataclass_t rdclass,
           dns_ttl_t ttl, isc_mem_t *mctx)
{
    dst_key_t *key;
    isc_result_t result;
    int i;

    key = (dst_key_t *) isc_mem_get(mctx, sizeof(dst_key_t));
    if (key == NULL)
        return (NULL);

    memset(key, 0, sizeof(dst_key_t));
    key->magic = KEY_MAGIC;

    result = isc_refcount_init(&key->refs, 1);
    if (result != ISC_R_SUCCESS) {
        isc_mem_put(mctx, key, sizeof(dst_key_t));
        return (NULL);
    }

    key->key_name = isc_mem_get(mctx, sizeof(dns_name_t));
    if (key->key_name == NULL) {
        isc_refcount_destroy(&key->refs);
        isc_mem_put(mctx, key, sizeof(dst_key_t));
        return (NULL);
    }
    dns_name_init(key->key_name, NULL);
    result = dns_name_dup(name, mctx, key->key_name);
    if (result != ISC_R_SUCCESS) {
        isc_refcount_destroy(&key->refs);
        isc_mem_put(mctx, key->key_name, sizeof(dns_name_t));
        isc_mem_put(mctx, key, sizeof(dst_key_t));
        return (NULL);
    }
    key->key_alg = alg;
    key->key_flags = flags;
    key->key_proto = protocol;
    key->mctx = mctx;
    key->keydata.generic = NULL;
    key->key_size = bits;
    key->key_class = rdclass;
    key->key_ttl = ttl;
    key->func = dst_t_func[alg];
    key->fmt_major = 0;
    key->fmt_minor = 0;
    for (i = 0; i < (DST_MAX_TIMES + 1); i++) {
        key->times[i] = 0;
        key->timeset[i] = ISC_FALSE;
    }
    return (key);
}

/*%
 * Reads a public key from disk
 */
isc_result_t
dst_key_read_public(const char *filename, int type,
            isc_mem_t *mctx, dst_key_t **keyp)
{
    u_char rdatabuf[DST_KEY_MAXSIZE];
    isc_buffer_t b;
    dns_fixedname_t name;
    isc_lex_t *lex = NULL;
    isc_token_t token;
    isc_result_t ret;
    dns_rdata_t rdata = DNS_RDATA_INIT;
    unsigned int opt = ISC_LEXOPT_DNSMULTILINE;
    dns_rdataclass_t rdclass = dns_rdataclass_in;
    isc_lexspecials_t specials;
    isc_uint32_t ttl = 0;
    isc_result_t result;
    dns_rdatatype_t keytype;

    /*
     * Open the file and read its formatted contents
     * File format:
     *    domain.name [ttl] [class] [KEY|DNSKEY] <flags> <protocol> <algorithm> <key>
     */

    /* 1500 should be large enough for any key */
    ret = isc_lex_create(mctx, 1500, &lex);
    if (ret != ISC_R_SUCCESS)
        goto cleanup;

    memset(specials, 0, sizeof(specials));
    specials['('] = 1;
    specials[')'] = 1;
    specials['"'] = 1;
    isc_lex_setspecials(lex, specials);
    isc_lex_setcomments(lex, ISC_LEXCOMMENT_DNSMASTERFILE);

    ret = isc_lex_openfile(lex, filename);
    if (ret != ISC_R_SUCCESS)
        goto cleanup;

#define NEXTTOKEN(lex, opt, token) { \
    ret = isc_lex_gettoken(lex, opt, token); \
    if (ret != ISC_R_SUCCESS) \
        goto cleanup; \
    }

#define BADTOKEN() { \
    ret = ISC_R_UNEXPECTEDTOKEN; \
    goto cleanup; \
    }

    /* Read the domain name */
    NEXTTOKEN(lex, opt, &token);
    if (token.type != isc_tokentype_string)
        BADTOKEN();

    /*
     * We don't support "@" in .key files.
     */
    if (!strcmp(DST_AS_STR(token), "@"))
        BADTOKEN();

    dns_fixedname_init(&name);
    isc_buffer_init(&b, DST_AS_STR(token), strlen(DST_AS_STR(token)));
    isc_buffer_add(&b, strlen(DST_AS_STR(token)));
    ret = dns_name_fromtext(dns_fixedname_name(&name), &b, dns_rootname,
                0, NULL);
    if (ret != ISC_R_SUCCESS)
        goto cleanup;

    /* Read the next word: either TTL, class, or 'KEY' */
    NEXTTOKEN(lex, opt, &token);

    if (token.type != isc_tokentype_string)
        BADTOKEN();

    /* If it's a TTL, read the next one */
    result = dns_ttl_fromtext(&token.value.as_textregion, &ttl);
    if (result == ISC_R_SUCCESS)
        NEXTTOKEN(lex, opt, &token);

    if (token.type != isc_tokentype_string)
        BADTOKEN();

    ret = dns_rdataclass_fromtext(&rdclass, &token.value.as_textregion);
    if (ret == ISC_R_SUCCESS)
        NEXTTOKEN(lex, opt, &token);

    if (token.type != isc_tokentype_string)
        BADTOKEN();

    if (strcasecmp(DST_AS_STR(token), "DNSKEY") == 0)
        keytype = dns_rdatatype_dnskey;
    else if (strcasecmp(DST_AS_STR(token), "KEY") == 0)
        keytype = dns_rdatatype_key; /*%< SIG(0), TKEY */
    else
        BADTOKEN();

    if (((type & DST_TYPE_KEY) != 0 && keytype != dns_rdatatype_key) ||
        ((type & DST_TYPE_KEY) == 0 && keytype != dns_rdatatype_dnskey)) {
        ret = DST_R_BADKEYTYPE;
        goto cleanup;
    }

    isc_buffer_init(&b, rdatabuf, sizeof(rdatabuf));
    ret = dns_rdata_fromtext(&rdata, rdclass, keytype, lex, NULL,
                 ISC_FALSE, mctx, &b, NULL);
    if (ret != ISC_R_SUCCESS)
        goto cleanup;

    ret = dst_key_fromdns(dns_fixedname_name(&name), rdclass, &b, mctx,
                  keyp);
    if (ret != ISC_R_SUCCESS)
        goto cleanup;

    dst_key_setttl(*keyp, ttl);

 cleanup:
    if (lex != NULL)
        isc_lex_destroy(&lex);
    return (ret);
}

static isc_boolean_t
issymmetric(const dst_key_t *key) {
    REQUIRE(dst_initialized == ISC_TRUE);
    REQUIRE(VALID_KEY(key));

    /* XXXVIX this switch statement is too sparse to gen a jump table. */
    switch (key->key_alg) {
    case DST_ALG_RSAMD5:
    case DST_ALG_RSASHA1:
    case DST_ALG_NSEC3RSASHA1:
    case DST_ALG_RSASHA256:
    case DST_ALG_RSASHA512:
    case DST_ALG_DSA:
    case DST_ALG_NSEC3DSA:
    case DST_ALG_DH:
    case DST_ALG_ECCGOST:
        return (ISC_FALSE);
    case DST_ALG_HMACMD5:
    case DST_ALG_GSSAPI:
        return (ISC_TRUE);
    default:
        return (ISC_FALSE);
    }
}

/*%
 * Write key timing metadata to a file pointer, preceded by 'tag'
 */
static void
printtime(const dst_key_t *key, int type, const char *tag, FILE *stream) {
    isc_result_t result;
#ifdef ISC_PLATFORM_USETHREADS
    char output[26]; /* Minimum buffer as per ctime_r() specification. */
#else
    const char *output;
#endif
    isc_stdtime_t when;
    time_t t;
    char utc[sizeof("YYYYMMDDHHSSMM")];
    isc_buffer_t b;
    isc_region_t r;

    result = dst_key_gettime(key, type, &when);
    if (result == ISC_R_NOTFOUND)
        return;

    /* time_t and isc_stdtime_t might be different sizes */
    t = when;
#ifdef ISC_PLATFORM_USETHREADS
#ifdef WIN32
    if (ctime_s(output, sizeof(output), &t) != 0)
        goto error;
#else
    if (ctime_r(&t, output) == NULL)
        goto error;
#endif
#else
    output = ctime(&t);
#endif

    isc_buffer_init(&b, utc, sizeof(utc));
    result = dns_time32_totext(when, &b);
    if (result != ISC_R_SUCCESS)
        goto error;

    isc_buffer_usedregion(&b, &r);
    fprintf(stream, "%s: %.*s (%.*s)\n", tag, (int)r.length, r.base,
         (int)strlen(output) - 1, output);
    return;

 error:
    fprintf(stream, "%s: (set, unable to display)\n", tag);
}

/*%
 * Writes a public key to disk in DNS format.
 */
static isc_result_t
write_public_key(const dst_key_t *key, int type, const char *directory) {
    FILE *fp;
    isc_buffer_t keyb, textb, fileb, classb;
    isc_region_t r;
    char filename[ISC_DIR_NAMEMAX];
    unsigned char key_array[DST_KEY_MAXSIZE];
    char text_array[DST_KEY_MAXTEXTSIZE];
    char class_array[10];
    isc_result_t ret;
    dns_rdata_t rdata = DNS_RDATA_INIT;
    isc_fsaccess_t access;

    REQUIRE(VALID_KEY(key));

    isc_buffer_init(&keyb, key_array, sizeof(key_array));
    isc_buffer_init(&textb, text_array, sizeof(text_array));
    isc_buffer_init(&classb, class_array, sizeof(class_array));

    ret = dst_key_todns(key, &keyb);
    if (ret != ISC_R_SUCCESS)
        return (ret);

    isc_buffer_usedregion(&keyb, &r);
    dns_rdata_fromregion(&rdata, key->key_class, dns_rdatatype_dnskey, &r);

    ret = dns_rdata_totext(&rdata, (dns_name_t *) NULL, &textb);
    if (ret != ISC_R_SUCCESS)
        return (DST_R_INVALIDPUBLICKEY);

    ret = dns_rdataclass_totext(key->key_class, &classb);
    if (ret != ISC_R_SUCCESS)
        return (DST_R_INVALIDPUBLICKEY);

    /*
     * Make the filename.
     */
    isc_buffer_init(&fileb, filename, sizeof(filename));
    ret = dst_key_buildfilename(key, DST_TYPE_PUBLIC, directory, &fileb);
    if (ret != ISC_R_SUCCESS)
        return (ret);

    /*
     * Create public key file.
     */
    if ((fp = fopen(filename, "w")) == NULL)
        return (DST_R_WRITEERROR);

    if (issymmetric(key)) {
        access = 0;
        isc_fsaccess_add(ISC_FSACCESS_OWNER,
                 ISC_FSACCESS_READ | ISC_FSACCESS_WRITE,
                 &access);
        (void)isc_fsaccess_set(filename, access);
    }

    /* Write key information in comments */
    if ((type & DST_TYPE_KEY) == 0) {
        fprintf(fp, "; This is a %s%s-signing key, keyid %d, for ",
            (key->key_flags & DNS_KEYFLAG_REVOKE) != 0 ?
                "revoked " :
                "",
            (key->key_flags & DNS_KEYFLAG_KSK) != 0 ?
                "key" :
                "zone",
            key->key_id);
        ret = dns_name_print(key->key_name, fp);
        if (ret != ISC_R_SUCCESS) {
            fclose(fp);
            return (ret);
        }
        fputc('\n', fp);

        printtime(key, DST_TIME_CREATED, "; Created", fp);
        printtime(key, DST_TIME_PUBLISH, "; Publish", fp);
        printtime(key, DST_TIME_ACTIVATE, "; Activate", fp);
        printtime(key, DST_TIME_REVOKE, "; Revoke", fp);
        printtime(key, DST_TIME_INACTIVE, "; Inactive", fp);
        printtime(key, DST_TIME_DELETE, "; Delete", fp);
    }

    /* Now print the actual key */
    ret = dns_name_print(key->key_name, fp);
    fprintf(fp, " ");

    if (key->key_ttl != 0)
        fprintf(fp, "%d ", key->key_ttl);

    isc_buffer_usedregion(&classb, &r);
    if ((unsigned)isc_util_fwrite(r.base, 1, r.length, fp) != r.length)
           ret = DST_R_WRITEERROR;

    if ((type & DST_TYPE_KEY) != 0)
        fprintf(fp, " KEY ");
    else
        fprintf(fp, " DNSKEY ");

    isc_buffer_usedregion(&textb, &r);
    if ((unsigned)isc_util_fwrite(r.base, 1, r.length, fp) != r.length)
           ret = DST_R_WRITEERROR;

    fputc('\n', fp);
    fflush(fp);
    if (ferror(fp))
        ret = DST_R_WRITEERROR;
    fclose(fp);

    return (ret);
}

static isc_result_t
buildfilename(dns_name_t *name, dns_keytag_t id,
          unsigned int alg, unsigned int type,
          const char *directory, isc_buffer_t *out)
{
    const char *suffix = "";
    unsigned int len;
    isc_result_t result;

    REQUIRE(out != NULL);
    if ((type & DST_TYPE_PRIVATE) != 0)
        suffix = ".private";
    else if (type == DST_TYPE_PUBLIC)
        suffix = ".key";
    if (directory != NULL) {
        if (isc_buffer_availablelength(out) < strlen(directory))
            return (ISC_R_NOSPACE);
        isc_buffer_putstr(out, directory);
        if (strlen(directory) > 0U &&
            directory[strlen(directory) - 1] != '/')
            isc_buffer_putstr(out, "/");
    }
    if (isc_buffer_availablelength(out) < 1)
        return (ISC_R_NOSPACE);
    isc_buffer_putstr(out, "K");
    result = dns_name_tofilenametext(name, ISC_FALSE, out);
    if (result != ISC_R_SUCCESS)
        return (result);
    len = 1 + 3 + 1 + 5 + strlen(suffix) + 1;
    if (isc_buffer_availablelength(out) < len)
        return (ISC_R_NOSPACE);
    sprintf((char *) isc_buffer_used(out), "+%03d+%05d%s", alg, id,
        suffix);
    isc_buffer_add(out, len);

    return (ISC_R_SUCCESS);
}

static isc_result_t
computeid(dst_key_t *key) {
    isc_buffer_t dnsbuf;
    unsigned char dns_array[DST_KEY_MAXSIZE];
    isc_region_t r;
    isc_result_t ret;

    isc_buffer_init(&dnsbuf, dns_array, sizeof(dns_array));
    ret = dst_key_todns(key, &dnsbuf);
    if (ret != ISC_R_SUCCESS)
        return (ret);

    isc_buffer_usedregion(&dnsbuf, &r);
    key->key_id = dst_region_computeid(&r, key->key_alg);
    return (ISC_R_SUCCESS);
}

static isc_result_t
frombuffer(dns_name_t *name, unsigned int alg, unsigned int flags,
       unsigned int protocol, dns_rdataclass_t rdclass,
       isc_buffer_t *source, isc_mem_t *mctx, dst_key_t **keyp)
{
    dst_key_t *key;
    isc_result_t ret;

    REQUIRE(dns_name_isabsolute(name));
    REQUIRE(source != NULL);
    REQUIRE(mctx != NULL);
    REQUIRE(keyp != NULL && *keyp == NULL);

    key = get_key_struct(name, alg, flags, protocol, 0, rdclass, 0, mctx);
    if (key == NULL)
        return (ISC_R_NOMEMORY);

    if (isc_buffer_remaininglength(source) > 0) {
        ret = algorithm_status(alg);
        if (ret != ISC_R_SUCCESS) {
            dst_key_free(&key);
            return (ret);
        }
        if (key->func->fromdns == NULL) {
            dst_key_free(&key);
            return (DST_R_UNSUPPORTEDALG);
        }

        ret = key->func->fromdns(key, source);
        if (ret != ISC_R_SUCCESS) {
            dst_key_free(&key);
            return (ret);
        }
    }

    *keyp = key;
    return (ISC_R_SUCCESS);
}

static isc_result_t
algorithm_status(unsigned int alg) {
    REQUIRE(dst_initialized == ISC_TRUE);

    if (dst_algorithm_supported(alg))
        return (ISC_R_SUCCESS);
#ifndef OPENSSL
    if (alg == DST_ALG_RSAMD5 || alg == DST_ALG_RSASHA1 ||
        alg == DST_ALG_DSA || alg == DST_ALG_DH ||
        alg == DST_ALG_HMACMD5 || alg == DST_ALG_NSEC3DSA ||
        alg == DST_ALG_NSEC3RSASHA1 ||
        alg == DST_ALG_RSASHA256 || alg == DST_ALG_RSASHA512 ||
        alg == DST_ALG_ECCGOST)
        return (DST_R_NOCRYPTO);
#endif
    return (DST_R_UNSUPPORTEDALG);
}

static isc_result_t
addsuffix(char *filename, int len, const char *odirname,
      const char *ofilename, const char *suffix)
{
    int olen = strlen(ofilename);
    int n;

    if (olen > 1 && ofilename[olen - 1] == '.')
        olen -= 1;
    else if (olen > 8 && strcmp(ofilename + olen - 8, ".private") == 0)
        olen -= 8;
    else if (olen > 4 && strcmp(ofilename + olen - 4, ".key") == 0)
        olen -= 4;

    if (odirname == NULL)
        n = snprintf(filename, len, "%.*s%s", olen, ofilename, suffix);
    else
        n = snprintf(filename, len, "%s/%.*s%s",
                 odirname, olen, ofilename, suffix);
    if (n < 0)
        return (ISC_R_FAILURE);
    if (n >= len)
        return (ISC_R_NOSPACE);
    return (ISC_R_SUCCESS);
}

isc_result_t
dst__entropy_getdata(void *buf, unsigned int len, isc_boolean_t pseudo) {
#ifdef BIND9
    unsigned int flags = dst_entropy_flags;

    if (len == 0)
        return (ISC_R_SUCCESS);
    if (pseudo)
        flags &= ~ISC_ENTROPY_GOODONLY;
    else
        flags |= ISC_ENTROPY_BLOCKING;
    return (isc_entropy_getdata(dst_entropy_pool, buf, len, NULL, flags));
#else
    UNUSED(buf);
    UNUSED(len);
    UNUSED(pseudo);

    return (ISC_R_NOTIMPLEMENTED);
#endif
}

unsigned int
dst__entropy_status(void) {
#ifdef BIND9
#ifdef GSSAPI
    unsigned int flags = dst_entropy_flags;
    isc_result_t ret;
    unsigned char buf[32];
    static isc_boolean_t first = ISC_TRUE;

    if (first) {
        /* Someone believes RAND_status() initializes the PRNG */
        flags &= ~ISC_ENTROPY_GOODONLY;
        ret = isc_entropy_getdata(dst_entropy_pool, buf,
                      sizeof(buf), NULL, flags);
        INSIST(ret == ISC_R_SUCCESS);
        isc_entropy_putdata(dst_entropy_pool, buf,
                    sizeof(buf), 2 * sizeof(buf));
        first = ISC_FALSE;
    }
#endif
    return (isc_entropy_status(dst_entropy_pool));
#else
    return (0);
#endif
}

isc_buffer_t *
dst_key_tkeytoken(const dst_key_t *key) {
    REQUIRE(VALID_KEY(key));
    return (key->key_tkeytoken);
}