tkey.c

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/*
 * Copyright (C) 2004-2015  Internet Systems Consortium, Inc. ("ISC")
 * Copyright (C) 1999-2001, 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 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.
 */

/*
 * $Id$
 */
/*! \file */
#include <config.h>

#include <isc/buffer.h>
#include <isc/entropy.h>
#include <isc/md5.h>
#include <isc/mem.h>
#include <isc/string.h>
#include <isc/util.h>

#include <dns/dnssec.h>
#include <dns/fixedname.h>
#include <dns/keyvalues.h>
#include <dns/log.h>
#include <dns/message.h>
#include <dns/name.h>
#include <dns/rdata.h>
#include <dns/rdatalist.h>
#include <dns/rdataset.h>
#include <dns/rdatastruct.h>
#include <dns/result.h>
#include <dns/tkey.h>
#include <dns/tsig.h>

#include <dst/dst.h>
#include <dst/gssapi.h>

#include "dst_internal.h"

#define TKEY_RANDOM_AMOUNT 16

#ifdef PKCS11CRYPTO
#include <pk11/pk11.h>
#endif

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

static void
tkey_log(const char *fmt, ...) ISC_FORMAT_PRINTF(1, 2);

static void
tkey_log(const char *fmt, ...) {
        va_list ap;

        va_start(ap, fmt);
        isc_log_vwrite(dns_lctx, DNS_LOGCATEGORY_GENERAL,
                       DNS_LOGMODULE_REQUEST, ISC_LOG_DEBUG(4), fmt, ap);
        va_end(ap);
}

static void
_dns_tkey_dumpmessage(dns_message_t *msg) {
        isc_buffer_t outbuf;
        unsigned char output[4096];
        isc_result_t result;

        isc_buffer_init(&outbuf, output, sizeof(output));
        result = dns_message_totext(msg, &dns_master_style_debug, 0,
                                    &outbuf);
        if (result != ISC_R_SUCCESS)
                fprintf(stderr, "Warning: dns_message_totext returned: %s\n",
                        dns_result_totext(result));
        fprintf(stderr, "%.*s\n", (int)isc_buffer_usedlength(&outbuf),
                (char *)isc_buffer_base(&outbuf));
}

isc_result_t
dns_tkeyctx_create(isc_mem_t *mctx, isc_entropy_t *ectx, dns_tkeyctx_t **tctxp)
{
        dns_tkeyctx_t *tctx;

        REQUIRE(mctx != NULL);
        REQUIRE(ectx != NULL);
        REQUIRE(tctxp != NULL && *tctxp == NULL);

        tctx = isc_mem_get(mctx, sizeof(dns_tkeyctx_t));
        if (tctx == NULL)
                return (ISC_R_NOMEMORY);
        tctx->mctx = NULL;
        isc_mem_attach(mctx, &tctx->mctx);
        tctx->ectx = NULL;
        isc_entropy_attach(ectx, &tctx->ectx);
        tctx->dhkey = NULL;
        tctx->domain = NULL;
        tctx->gsscred = NULL;
        tctx->gssapi_keytab = NULL;

        *tctxp = tctx;
        return (ISC_R_SUCCESS);
}

void
dns_tkeyctx_destroy(dns_tkeyctx_t **tctxp) {
        isc_mem_t *mctx;
        dns_tkeyctx_t *tctx;

        REQUIRE(tctxp != NULL && *tctxp != NULL);

        tctx = *tctxp;
        mctx = tctx->mctx;

        if (tctx->dhkey != NULL)
                dst_key_free(&tctx->dhkey);
        if (tctx->domain != NULL) {
                if (dns_name_dynamic(tctx->domain))
                        dns_name_free(tctx->domain, mctx);
                isc_mem_put(mctx, tctx->domain, sizeof(dns_name_t));
        }
        if (tctx->gssapi_keytab != NULL) {
                isc_mem_free(mctx, tctx->gssapi_keytab);
        }
        if (tctx->gsscred != NULL)
                dst_gssapi_releasecred(&tctx->gsscred);
        isc_entropy_detach(&tctx->ectx);
        isc_mem_put(mctx, tctx, sizeof(dns_tkeyctx_t));
        isc_mem_detach(&mctx);
        *tctxp = NULL;
}

static isc_result_t
add_rdata_to_list(dns_message_t *msg, dns_name_t *name, dns_rdata_t *rdata,
                isc_uint32_t ttl, dns_namelist_t *namelist)
{
        isc_result_t result;
        isc_region_t r, newr;
        dns_rdata_t *newrdata = NULL;
        dns_name_t *newname = NULL;
        dns_rdatalist_t *newlist = NULL;
        dns_rdataset_t *newset = NULL;
        isc_buffer_t *tmprdatabuf = NULL;

        RETERR(dns_message_gettemprdata(msg, &newrdata));

        dns_rdata_toregion(rdata, &r);
        RETERR(isc_buffer_allocate(msg->mctx, &tmprdatabuf, r.length));
        isc_buffer_availableregion(tmprdatabuf, &newr);
        memmove(newr.base, r.base, r.length);
        dns_rdata_fromregion(newrdata, rdata->rdclass, rdata->type, &newr);
        dns_message_takebuffer(msg, &tmprdatabuf);

        RETERR(dns_message_gettempname(msg, &newname));
        dns_name_init(newname, NULL);
        RETERR(dns_name_dup(name, msg->mctx, newname));

        RETERR(dns_message_gettemprdatalist(msg, &newlist));
        newlist->rdclass = newrdata->rdclass;
        newlist->type = newrdata->type;
        newlist->ttl = ttl;
        ISC_LIST_APPEND(newlist->rdata, newrdata, link);

        RETERR(dns_message_gettemprdataset(msg, &newset));
        dns_rdataset_init(newset);
        RETERR(dns_rdatalist_tordataset(newlist, newset));

        ISC_LIST_INIT(newname->list);
        ISC_LIST_APPEND(newname->list, newset, link);

        ISC_LIST_APPEND(*namelist, newname, link);

        return (ISC_R_SUCCESS);

 failure:
        if (newrdata != NULL) {
                if (ISC_LINK_LINKED(newrdata, link)) {
                        INSIST(newlist != NULL);
                        ISC_LIST_UNLINK(newlist->rdata, newrdata, link);
                }
                dns_message_puttemprdata(msg, &newrdata);
        }
        if (newname != NULL)
                dns_message_puttempname(msg, &newname);
        if (newset != NULL) {
                dns_rdataset_disassociate(newset);
                dns_message_puttemprdataset(msg, &newset);
        }
        if (newlist != NULL)
                dns_message_puttemprdatalist(msg, &newlist);
        return (result);
}

static void
free_namelist(dns_message_t *msg, dns_namelist_t *namelist) {
        dns_name_t *name;
        dns_rdataset_t *set;

        while (!ISC_LIST_EMPTY(*namelist)) {
                name = ISC_LIST_HEAD(*namelist);
                ISC_LIST_UNLINK(*namelist, name, link);
                while (!ISC_LIST_EMPTY(name->list)) {
                        set = ISC_LIST_HEAD(name->list);
                        ISC_LIST_UNLINK(name->list, set, link);
                        dns_message_puttemprdataset(msg, &set);
                }
                dns_message_puttempname(msg, &name);
        }
}

static isc_result_t
compute_secret(isc_buffer_t *shared, isc_region_t *queryrandomness,
               isc_region_t *serverrandomness, isc_buffer_t *secret)
{
        isc_md5_t md5ctx;
        isc_region_t r, r2;
        unsigned char digests[32];
        unsigned int i;

        isc_buffer_usedregion(shared, &r);

        /*
         * MD5 ( query data | DH value ).
         */
        isc_md5_init(&md5ctx);
        isc_md5_update(&md5ctx, queryrandomness->base,
                       queryrandomness->length);
        isc_md5_update(&md5ctx, r.base, r.length);
        isc_md5_final(&md5ctx, digests);

        /*
         * MD5 ( server data | DH value ).
         */
        isc_md5_init(&md5ctx);
        isc_md5_update(&md5ctx, serverrandomness->base,
                       serverrandomness->length);
        isc_md5_update(&md5ctx, r.base, r.length);
        isc_md5_final(&md5ctx, &digests[ISC_MD5_DIGESTLENGTH]);

        /*
         * XOR ( DH value, MD5-1 | MD5-2).
         */
        isc_buffer_availableregion(secret, &r);
        isc_buffer_usedregion(shared, &r2);
        if (r.length < sizeof(digests) || r.length < r2.length)
                return (ISC_R_NOSPACE);
        if (r2.length > sizeof(digests)) {
                memmove(r.base, r2.base, r2.length);
                for (i = 0; i < sizeof(digests); i++)
                        r.base[i] ^= digests[i];
                isc_buffer_add(secret, r2.length);
        } else {
                memmove(r.base, digests, sizeof(digests));
                for (i = 0; i < r2.length; i++)
                        r.base[i] ^= r2.base[i];
                isc_buffer_add(secret, sizeof(digests));
        }
        return (ISC_R_SUCCESS);

}

static isc_result_t
process_dhtkey(dns_message_t *msg, dns_name_t *signer, dns_name_t *name,
               dns_rdata_tkey_t *tkeyin, dns_tkeyctx_t *tctx,
               dns_rdata_tkey_t *tkeyout,
               dns_tsig_keyring_t *ring, dns_namelist_t *namelist)
{
        isc_result_t result = ISC_R_SUCCESS;
        dns_name_t *keyname, ourname;
        dns_rdataset_t *keyset = NULL;
        dns_rdata_t keyrdata = DNS_RDATA_INIT, ourkeyrdata = DNS_RDATA_INIT;
        isc_boolean_t found_key = ISC_FALSE, found_incompatible = ISC_FALSE;
        dst_key_t *pubkey = NULL;
        isc_buffer_t ourkeybuf, *shared = NULL;
        isc_region_t r, r2, ourkeyr;
        unsigned char keydata[DST_KEY_MAXSIZE];
        unsigned int sharedsize;
        isc_buffer_t secret;
        unsigned char *randomdata = NULL, secretdata[256];
        dns_ttl_t ttl = 0;

        if (tctx->dhkey == NULL) {
                tkey_log("process_dhtkey: tkey-dhkey not defined");
                tkeyout->error = dns_tsigerror_badalg;
                return (DNS_R_REFUSED);
        }

        if (!dns_name_equal(&tkeyin->algorithm, DNS_TSIG_HMACMD5_NAME)) {
                tkey_log("process_dhtkey: algorithms other than "
                         "hmac-md5 are not supported");
                tkeyout->error = dns_tsigerror_badalg;
                return (ISC_R_SUCCESS);
        }

        /*
         * Look for a DH KEY record that will work with ours.
         */
        for (result = dns_message_firstname(msg, DNS_SECTION_ADDITIONAL);
             result == ISC_R_SUCCESS && !found_key;
             result = dns_message_nextname(msg, DNS_SECTION_ADDITIONAL)) {
                keyname = NULL;
                dns_message_currentname(msg, DNS_SECTION_ADDITIONAL, &keyname);
                keyset = NULL;
                result = dns_message_findtype(keyname, dns_rdatatype_key, 0,
                                              &keyset);
                if (result != ISC_R_SUCCESS)
                        continue;

                for (result = dns_rdataset_first(keyset);
                     result == ISC_R_SUCCESS && !found_key;
                     result = dns_rdataset_next(keyset)) {
                        dns_rdataset_current(keyset, &keyrdata);
                        pubkey = NULL;
                        result = dns_dnssec_keyfromrdata(keyname, &keyrdata,
                                                         msg->mctx, &pubkey);
                        if (result != ISC_R_SUCCESS) {
                                dns_rdata_reset(&keyrdata);
                                continue;
                        }
                        if (dst_key_alg(pubkey) == DNS_KEYALG_DH) {
                                if (dst_key_paramcompare(pubkey, tctx->dhkey))
                                {
                                        found_key = ISC_TRUE;
                                        ttl = keyset->ttl;
                                        break;
                                } else
                                        found_incompatible = ISC_TRUE;
                        }
                        dst_key_free(&pubkey);
                        dns_rdata_reset(&keyrdata);
                }
        }

        if (!found_key) {
                if (found_incompatible) {
                        tkey_log("process_dhtkey: found an incompatible key");
                        tkeyout->error = dns_tsigerror_badkey;
                        return (ISC_R_SUCCESS);
                } else {
                        tkey_log("process_dhtkey: failed to find a key");
                        return (DNS_R_FORMERR);
                }
        }

        RETERR(add_rdata_to_list(msg, keyname, &keyrdata, ttl, namelist));

        isc_buffer_init(&ourkeybuf, keydata, sizeof(keydata));
        RETERR(dst_key_todns(tctx->dhkey, &ourkeybuf));
        isc_buffer_usedregion(&ourkeybuf, &ourkeyr);
        dns_rdata_fromregion(&ourkeyrdata, dns_rdataclass_any,
                             dns_rdatatype_key, &ourkeyr);

        dns_name_init(&ourname, NULL);
        dns_name_clone(dst_key_name(tctx->dhkey), &ourname);

        /*
         * XXXBEW The TTL should be obtained from the database, if it exists.
         */
        RETERR(add_rdata_to_list(msg, &ourname, &ourkeyrdata, 0, namelist));

        RETERR(dst_key_secretsize(tctx->dhkey, &sharedsize));
        RETERR(isc_buffer_allocate(msg->mctx, &shared, sharedsize));

        result = dst_key_computesecret(pubkey, tctx->dhkey, shared);
        if (result != ISC_R_SUCCESS) {
                tkey_log("process_dhtkey: failed to compute shared secret: %s",
                         isc_result_totext(result));
                goto failure;
        }
        dst_key_free(&pubkey);

        isc_buffer_init(&secret, secretdata, sizeof(secretdata));

        randomdata = isc_mem_get(tkeyout->mctx, TKEY_RANDOM_AMOUNT);
        if (randomdata == NULL)
                goto failure;

        result = dst__entropy_getdata(randomdata, TKEY_RANDOM_AMOUNT,
                                      ISC_FALSE);
        if (result != ISC_R_SUCCESS) {
                tkey_log("process_dhtkey: failed to obtain entropy: %s",
                         isc_result_totext(result));
                goto failure;
        }

        r.base = randomdata;
        r.length = TKEY_RANDOM_AMOUNT;
        r2.base = tkeyin->key;
        r2.length = tkeyin->keylen;
        RETERR(compute_secret(shared, &r2, &r, &secret));
        isc_buffer_free(&shared);

        RETERR(dns_tsigkey_create(name, &tkeyin->algorithm,
                                  isc_buffer_base(&secret),
                                  isc_buffer_usedlength(&secret),
                                  ISC_TRUE, signer, tkeyin->inception,
                                  tkeyin->expire, ring->mctx, ring, NULL));

        /* This key is good for a long time */
        tkeyout->inception = tkeyin->inception;
        tkeyout->expire = tkeyin->expire;

        tkeyout->key = randomdata;
        tkeyout->keylen = TKEY_RANDOM_AMOUNT;

        return (ISC_R_SUCCESS);

 failure:
        if (!ISC_LIST_EMPTY(*namelist))
                free_namelist(msg, namelist);
        if (shared != NULL)
                isc_buffer_free(&shared);
        if (pubkey != NULL)
                dst_key_free(&pubkey);
        if (randomdata != NULL)
                isc_mem_put(tkeyout->mctx, randomdata, TKEY_RANDOM_AMOUNT);
        return (result);
}

static isc_result_t
process_gsstkey(dns_name_t *name, dns_rdata_tkey_t *tkeyin,
                dns_tkeyctx_t *tctx, dns_rdata_tkey_t *tkeyout,
                dns_tsig_keyring_t *ring)
{
        isc_result_t result = ISC_R_SUCCESS;
        dst_key_t *dstkey = NULL;
        dns_tsigkey_t *tsigkey = NULL;
        dns_fixedname_t principal;
        isc_stdtime_t now;
        isc_region_t intoken;
        isc_buffer_t *outtoken = NULL;
        gss_ctx_id_t gss_ctx = NULL;

        /*
         * You have to define either a gss credential (principal) to
         * accept with tkey-gssapi-credential, or you have to
         * configure a specific keytab (with tkey-gssapi-keytab) in
         * order to use gsstkey
         */
        if (tctx->gsscred == NULL && tctx->gssapi_keytab == NULL) {
                tkey_log("process_gsstkey(): no tkey-gssapi-credential "
                         "or tkey-gssapi-keytab configured");
                return (ISC_R_NOPERM);
        }

        if (!dns_name_equal(&tkeyin->algorithm, DNS_TSIG_GSSAPI_NAME) &&
            !dns_name_equal(&tkeyin->algorithm, DNS_TSIG_GSSAPIMS_NAME)) {
                tkeyout->error = dns_tsigerror_badalg;
                tkey_log("process_gsstkey(): dns_tsigerror_badalg");    /* XXXSRA */
                return (ISC_R_SUCCESS);
        }

        /*
         * XXXDCL need to check for key expiry per 4.1.1
         * XXXDCL need a way to check fully established, perhaps w/key_flags
         */

        intoken.base = tkeyin->key;
        intoken.length = tkeyin->keylen;

        result = dns_tsigkey_find(&tsigkey, name, &tkeyin->algorithm, ring);
        if (result == ISC_R_SUCCESS)
                gss_ctx = dst_key_getgssctx(tsigkey->key);

        dns_fixedname_init(&principal);

        /*
         * Note that tctx->gsscred may be NULL if tctx->gssapi_keytab is set
         */
        result = dst_gssapi_acceptctx(tctx->gsscred, tctx->gssapi_keytab,
                                      &intoken,
                                      &outtoken, &gss_ctx,
                                      dns_fixedname_name(&principal),
                                      tctx->mctx);
        if (result == DNS_R_INVALIDTKEY) {
                if (tsigkey != NULL)
                        dns_tsigkey_detach(&tsigkey);
                tkeyout->error = dns_tsigerror_badkey;
                tkey_log("process_gsstkey(): dns_tsigerror_badkey");    /* XXXSRA */
                return (ISC_R_SUCCESS);
        }
        if (result != DNS_R_CONTINUE && result != ISC_R_SUCCESS)
                goto failure;
        /*
         * XXXDCL Section 4.1.3: Limit GSS_S_CONTINUE_NEEDED to 10 times.
         */

        isc_stdtime_get(&now);

        if (tsigkey == NULL) {
#ifdef GSSAPI
                OM_uint32 gret, minor, lifetime;
#endif
                isc_uint32_t expire;

                RETERR(dst_key_fromgssapi(name, gss_ctx, ring->mctx,
                                          &dstkey, &intoken));
                /*
                 * Limit keys to 1 hour or the context's lifetime whichever
                 * is smaller.
                 */
                expire = now + 3600;
#ifdef GSSAPI
                gret = gss_context_time(&minor, gss_ctx, &lifetime);
                if (gret == GSS_S_COMPLETE && now + lifetime < expire)
                        expire = now + lifetime;
#endif
                RETERR(dns_tsigkey_createfromkey(name, &tkeyin->algorithm,
                                                 dstkey, ISC_TRUE,
                                                 dns_fixedname_name(&principal),
                                                 now, expire, ring->mctx, ring,
                                                 NULL));
                dst_key_free(&dstkey);
                tkeyout->inception = now;
                tkeyout->expire = expire;
        } else {
                tkeyout->inception = tsigkey->inception;
                tkeyout->expire = tsigkey->expire;
                dns_tsigkey_detach(&tsigkey);
        }

        if (outtoken) {
                tkeyout->key = isc_mem_get(tkeyout->mctx,
                                           isc_buffer_usedlength(outtoken));
                if (tkeyout->key == NULL) {
                        result = ISC_R_NOMEMORY;
                        goto failure;
                }
                tkeyout->keylen = isc_buffer_usedlength(outtoken);
                memmove(tkeyout->key, isc_buffer_base(outtoken),
                       isc_buffer_usedlength(outtoken));
                isc_buffer_free(&outtoken);
        } else {
                tkeyout->key = isc_mem_get(tkeyout->mctx, tkeyin->keylen);
                if (tkeyout->key == NULL) {
                        result = ISC_R_NOMEMORY;
                        goto failure;
                }
                tkeyout->keylen = tkeyin->keylen;
                memmove(tkeyout->key, tkeyin->key, tkeyin->keylen);
        }

        tkeyout->error = dns_rcode_noerror;

        tkey_log("process_gsstkey(): dns_tsigerror_noerror");   /* XXXSRA */

        return (ISC_R_SUCCESS);

failure:
        if (tsigkey != NULL)
                dns_tsigkey_detach(&tsigkey);

        if (dstkey != NULL)
                dst_key_free(&dstkey);

        if (outtoken != NULL)
                isc_buffer_free(&outtoken);

        tkey_log("process_gsstkey(): %s",
                isc_result_totext(result));     /* XXXSRA */

        return (result);
}

static isc_result_t
process_deletetkey(dns_name_t *signer, dns_name_t *name,
                   dns_rdata_tkey_t *tkeyin, dns_rdata_tkey_t *tkeyout,
                   dns_tsig_keyring_t *ring)
{
        isc_result_t result;
        dns_tsigkey_t *tsigkey = NULL;
        dns_name_t *identity;

        result = dns_tsigkey_find(&tsigkey, name, &tkeyin->algorithm, ring);
        if (result != ISC_R_SUCCESS) {
                tkeyout->error = dns_tsigerror_badname;
                return (ISC_R_SUCCESS);
        }

        /*
         * Only allow a delete if the identity that created the key is the
         * same as the identity that signed the message.
         */
        identity = dns_tsigkey_identity(tsigkey);
        if (identity == NULL || !dns_name_equal(identity, signer)) {
                dns_tsigkey_detach(&tsigkey);
                return (DNS_R_REFUSED);
        }

        /*
         * Set the key to be deleted when no references are left.  If the key
         * was not generated with TKEY and is in the config file, it may be
         * reloaded later.
         */
        dns_tsigkey_setdeleted(tsigkey);

        /* Release the reference */
        dns_tsigkey_detach(&tsigkey);

        return (ISC_R_SUCCESS);
}

isc_result_t
dns_tkey_processquery(dns_message_t *msg, dns_tkeyctx_t *tctx,
                      dns_tsig_keyring_t *ring)
{
        isc_result_t result = ISC_R_SUCCESS;
        dns_rdata_tkey_t tkeyin, tkeyout;
        isc_boolean_t freetkeyin = ISC_FALSE;
        dns_name_t *qname, *name, *keyname, *signer, tsigner;
        dns_fixedname_t fkeyname;
        dns_rdataset_t *tkeyset;
        dns_rdata_t rdata;
        dns_namelist_t namelist;
        char tkeyoutdata[512];
        isc_buffer_t tkeyoutbuf;

        REQUIRE(msg != NULL);
        REQUIRE(tctx != NULL);
        REQUIRE(ring != NULL);

        ISC_LIST_INIT(namelist);

        /*
         * Interpret the question section.
         */
        result = dns_message_firstname(msg, DNS_SECTION_QUESTION);
        if (result != ISC_R_SUCCESS)
                return (DNS_R_FORMERR);

        qname = NULL;
        dns_message_currentname(msg, DNS_SECTION_QUESTION, &qname);

        /*
         * Look for a TKEY record that matches the question.
         */
        tkeyset = NULL;
        name = NULL;
        result = dns_message_findname(msg, DNS_SECTION_ADDITIONAL, qname,
                                      dns_rdatatype_tkey, 0, &name, &tkeyset);
        if (result != ISC_R_SUCCESS) {
                /*
                 * Try the answer section, since that's where Win2000
                 * puts it.
                 */
                if (dns_message_findname(msg, DNS_SECTION_ANSWER, qname,
                                         dns_rdatatype_tkey, 0, &name,
                                         &tkeyset) != ISC_R_SUCCESS) {
                        result = DNS_R_FORMERR;
                        tkey_log("dns_tkey_processquery: couldn't find a TKEY "
                                 "matching the question");
                        goto failure;
                }
        }
        result = dns_rdataset_first(tkeyset);
        if (result != ISC_R_SUCCESS) {
                result = DNS_R_FORMERR;
                goto failure;
        }
        dns_rdata_init(&rdata);
        dns_rdataset_current(tkeyset, &rdata);

        RETERR(dns_rdata_tostruct(&rdata, &tkeyin, NULL));
        freetkeyin = ISC_TRUE;

        if (tkeyin.error != dns_rcode_noerror) {
                result = DNS_R_FORMERR;
                goto failure;
        }

        /*
         * Before we go any farther, verify that the message was signed.
         * GSSAPI TKEY doesn't require a signature, the rest do.
         */
        dns_name_init(&tsigner, NULL);
        result = dns_message_signer(msg, &tsigner);
        if (result != ISC_R_SUCCESS) {
                if (tkeyin.mode == DNS_TKEYMODE_GSSAPI &&
                    result == ISC_R_NOTFOUND)
                       signer = NULL;
                else {
                        tkey_log("dns_tkey_processquery: query was not "
                                 "properly signed - rejecting");
                        result = DNS_R_FORMERR;
                        goto failure;
                }
        } else
                signer = &tsigner;

        tkeyout.common.rdclass = tkeyin.common.rdclass;
        tkeyout.common.rdtype = tkeyin.common.rdtype;
        ISC_LINK_INIT(&tkeyout.common, link);
        tkeyout.mctx = msg->mctx;

        dns_name_init(&tkeyout.algorithm, NULL);
        dns_name_clone(&tkeyin.algorithm, &tkeyout.algorithm);

        tkeyout.inception = tkeyout.expire = 0;
        tkeyout.mode = tkeyin.mode;
        tkeyout.error = 0;
        tkeyout.keylen = tkeyout.otherlen = 0;
        tkeyout.key = tkeyout.other = NULL;

        /*
         * A delete operation must have a fully specified key name.  If this
         * is not a delete, we do the following:
         * if (qname != ".")
         *      keyname = qname + defaultdomain
         * else
         *      keyname = <random hex> + defaultdomain
         */
        if (tkeyin.mode != DNS_TKEYMODE_DELETE) {
                dns_tsigkey_t *tsigkey = NULL;

                if (tctx->domain == NULL && tkeyin.mode != DNS_TKEYMODE_GSSAPI) {
                        tkey_log("dns_tkey_processquery: tkey-domain not set");
                        result = DNS_R_REFUSED;
                        goto failure;
                }

                dns_fixedname_init(&fkeyname);
                keyname = dns_fixedname_name(&fkeyname);

                if (!dns_name_equal(qname, dns_rootname)) {
                        unsigned int n = dns_name_countlabels(qname);
                        RUNTIME_CHECK(dns_name_copy(qname, keyname, NULL)
                                      == ISC_R_SUCCESS);
                        dns_name_getlabelsequence(keyname, 0, n - 1, keyname);
                } else {
                        static char hexdigits[16] = {
                                '0', '1', '2', '3', '4', '5', '6', '7',
                                '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
                        unsigned char randomdata[16];
                        char randomtext[32];
                        isc_buffer_t b;
                        unsigned int i, j;

                        result = isc_entropy_getdata(tctx->ectx,
                                                     randomdata,
                                                     sizeof(randomdata),
                                                     NULL, 0);
                        if (result != ISC_R_SUCCESS)
                                goto failure;

                        for (i = 0, j = 0; i < sizeof(randomdata); i++) {
                                unsigned char val = randomdata[i];
                                randomtext[j++] = hexdigits[val >> 4];
                                randomtext[j++] = hexdigits[val & 0xF];
                        }
                        isc_buffer_init(&b, randomtext, sizeof(randomtext));
                        isc_buffer_add(&b, sizeof(randomtext));
                        result = dns_name_fromtext(keyname, &b, NULL, 0, NULL);
                        if (result != ISC_R_SUCCESS)
                                goto failure;
                }

                if (tkeyin.mode == DNS_TKEYMODE_GSSAPI) {
                        /* Yup.  This is a hack */
                        result = dns_name_concatenate(keyname, dns_rootname,
                                                      keyname, NULL);
                        if (result != ISC_R_SUCCESS)
                                goto failure;
                } else {
                        result = dns_name_concatenate(keyname, tctx->domain,
                                                      keyname, NULL);
                        if (result != ISC_R_SUCCESS)
                                goto failure;
                }

                result = dns_tsigkey_find(&tsigkey, keyname, NULL, ring);

                if (result == ISC_R_SUCCESS) {
                        tkeyout.error = dns_tsigerror_badname;
                        dns_tsigkey_detach(&tsigkey);
                        goto failure_with_tkey;
                } else if (result != ISC_R_NOTFOUND)
                        goto failure;
        } else
                keyname = qname;

        switch (tkeyin.mode) {
                case DNS_TKEYMODE_DIFFIEHELLMAN:
                        tkeyout.error = dns_rcode_noerror;
                        RETERR(process_dhtkey(msg, signer, keyname, &tkeyin,
                                              tctx, &tkeyout, ring,
                                              &namelist));
                        break;
                case DNS_TKEYMODE_GSSAPI:
                        tkeyout.error = dns_rcode_noerror;
                        RETERR(process_gsstkey(keyname, &tkeyin, tctx,
                                               &tkeyout, ring));
                        break;
                case DNS_TKEYMODE_DELETE:
                        tkeyout.error = dns_rcode_noerror;
                        RETERR(process_deletetkey(signer, keyname, &tkeyin,
                                                  &tkeyout, ring));
                        break;
                case DNS_TKEYMODE_SERVERASSIGNED:
                case DNS_TKEYMODE_RESOLVERASSIGNED:
                        result = DNS_R_NOTIMP;
                        goto failure;
                default:
                        tkeyout.error = dns_tsigerror_badmode;
        }

 failure_with_tkey:
        dns_rdata_init(&rdata);
        isc_buffer_init(&tkeyoutbuf, tkeyoutdata, sizeof(tkeyoutdata));
        result = dns_rdata_fromstruct(&rdata, tkeyout.common.rdclass,
                                      tkeyout.common.rdtype, &tkeyout,
                                      &tkeyoutbuf);

        if (freetkeyin) {
                dns_rdata_freestruct(&tkeyin);
                freetkeyin = ISC_FALSE;
        }

        if (tkeyout.key != NULL)
                isc_mem_put(tkeyout.mctx, tkeyout.key, tkeyout.keylen);
        if (tkeyout.other != NULL)
                isc_mem_put(tkeyout.mctx, tkeyout.other, tkeyout.otherlen);
        if (result != ISC_R_SUCCESS)
                goto failure;

        RETERR(add_rdata_to_list(msg, keyname, &rdata, 0, &namelist));

        RETERR(dns_message_reply(msg, ISC_TRUE));

        name = ISC_LIST_HEAD(namelist);
        while (name != NULL) {
                dns_name_t *next = ISC_LIST_NEXT(name, link);
                ISC_LIST_UNLINK(namelist, name, link);
                dns_message_addname(msg, name, DNS_SECTION_ANSWER);
                name = next;
        }

        return (ISC_R_SUCCESS);

 failure:
        if (freetkeyin)
                dns_rdata_freestruct(&tkeyin);
        if (!ISC_LIST_EMPTY(namelist))
                free_namelist(msg, &namelist);
        return (result);
}

static isc_result_t
buildquery(dns_message_t *msg, dns_name_t *name,
           dns_rdata_tkey_t *tkey, isc_boolean_t win2k)
{
        dns_name_t *qname = NULL, *aname = NULL;
        dns_rdataset_t *question = NULL, *tkeyset = NULL;
        dns_rdatalist_t *tkeylist = NULL;
        dns_rdata_t *rdata = NULL;
        isc_buffer_t *dynbuf = NULL, *anamebuf = NULL, *qnamebuf = NULL;
        isc_result_t result;

        REQUIRE(msg != NULL);
        REQUIRE(name != NULL);
        REQUIRE(tkey != NULL);

        RETERR(dns_message_gettempname(msg, &qname));
        RETERR(dns_message_gettempname(msg, &aname));

        RETERR(dns_message_gettemprdataset(msg, &question));
        dns_rdataset_init(question);
        dns_rdataset_makequestion(question, dns_rdataclass_any,
                                  dns_rdatatype_tkey);

        RETERR(isc_buffer_allocate(msg->mctx, &dynbuf, 4096));
        RETERR(isc_buffer_allocate(msg->mctx, &anamebuf, DNS_NAME_MAXWIRE));
        RETERR(isc_buffer_allocate(msg->mctx, &qnamebuf, DNS_NAME_MAXWIRE));
        RETERR(dns_message_gettemprdata(msg, &rdata));

        RETERR(dns_rdata_fromstruct(rdata, dns_rdataclass_any,
                                    dns_rdatatype_tkey, tkey, dynbuf));
        dns_message_takebuffer(msg, &dynbuf);

        RETERR(dns_message_gettemprdatalist(msg, &tkeylist));
        tkeylist->rdclass = dns_rdataclass_any;
        tkeylist->type = dns_rdatatype_tkey;
        ISC_LIST_APPEND(tkeylist->rdata, rdata, link);

        RETERR(dns_message_gettemprdataset(msg, &tkeyset));
        dns_rdataset_init(tkeyset);
        RETERR(dns_rdatalist_tordataset(tkeylist, tkeyset));

        dns_name_init(qname, NULL);
        dns_name_copy(name, qname, qnamebuf);

        dns_name_init(aname, NULL);
        dns_name_copy(name, aname, anamebuf);

        ISC_LIST_APPEND(qname->list, question, link);
        ISC_LIST_APPEND(aname->list, tkeyset, link);

        dns_message_addname(msg, qname, DNS_SECTION_QUESTION);
        dns_message_takebuffer(msg, &qnamebuf);

        /*
         * Windows 2000 needs this in the answer section, not the additional
         * section where the RFC specifies.
         */
        if (win2k)
                dns_message_addname(msg, aname, DNS_SECTION_ANSWER);
        else
                dns_message_addname(msg, aname, DNS_SECTION_ADDITIONAL);
        dns_message_takebuffer(msg, &anamebuf);

        return (ISC_R_SUCCESS);

 failure:
        if (qname != NULL)
                dns_message_puttempname(msg, &qname);
        if (aname != NULL)
                dns_message_puttempname(msg, &aname);
        if (question != NULL) {
                dns_rdataset_disassociate(question);
                dns_message_puttemprdataset(msg, &question);
        }
        if (dynbuf != NULL)
                isc_buffer_free(&dynbuf);
        if (qnamebuf != NULL)
                isc_buffer_free(&qnamebuf);
        if (anamebuf != NULL)
                isc_buffer_free(&anamebuf);
        printf("buildquery error\n");
        return (result);
}

isc_result_t
dns_tkey_builddhquery(dns_message_t *msg, dst_key_t *key, dns_name_t *name,
                      dns_name_t *algorithm, isc_buffer_t *nonce,
                      isc_uint32_t lifetime)
{
        dns_rdata_tkey_t tkey;
        dns_rdata_t *rdata = NULL;
        isc_buffer_t *dynbuf = NULL;
        isc_region_t r;
        dns_name_t keyname;
        dns_namelist_t namelist;
        isc_result_t result;
        isc_stdtime_t now;

        REQUIRE(msg != NULL);
        REQUIRE(key != NULL);
        REQUIRE(dst_key_alg(key) == DNS_KEYALG_DH);
        REQUIRE(dst_key_isprivate(key));
        REQUIRE(name != NULL);
        REQUIRE(algorithm != NULL);

        tkey.common.rdclass = dns_rdataclass_any;
        tkey.common.rdtype = dns_rdatatype_tkey;
        ISC_LINK_INIT(&tkey.common, link);
        tkey.mctx = msg->mctx;
        dns_name_init(&tkey.algorithm, NULL);
        dns_name_clone(algorithm, &tkey.algorithm);
        isc_stdtime_get(&now);
        tkey.inception = now;
        tkey.expire = now + lifetime;
        tkey.mode = DNS_TKEYMODE_DIFFIEHELLMAN;
        if (nonce != NULL)
                isc_buffer_usedregion(nonce, &r);
        else {
                r.base = isc_mem_get(msg->mctx, 0);
                r.length = 0;
        }
        tkey.error = 0;
        tkey.key = r.base;
        tkey.keylen =  r.length;
        tkey.other = NULL;
        tkey.otherlen = 0;

        RETERR(buildquery(msg, name, &tkey, ISC_FALSE));

        if (nonce == NULL)
                isc_mem_put(msg->mctx, r.base, 0);

        RETERR(dns_message_gettemprdata(msg, &rdata));
        RETERR(isc_buffer_allocate(msg->mctx, &dynbuf, 1024));
        RETERR(dst_key_todns(key, dynbuf));
        isc_buffer_usedregion(dynbuf, &r);
        dns_rdata_fromregion(rdata, dns_rdataclass_any,
                             dns_rdatatype_key, &r);
        dns_message_takebuffer(msg, &dynbuf);

        dns_name_init(&keyname, NULL);
        dns_name_clone(dst_key_name(key), &keyname);

        ISC_LIST_INIT(namelist);
        RETERR(add_rdata_to_list(msg, &keyname, rdata, 0, &namelist));
        name = ISC_LIST_HEAD(namelist);
        while (name != NULL) {
                dns_name_t *next = ISC_LIST_NEXT(name, link);
                ISC_LIST_UNLINK(namelist, name, link);
                dns_message_addname(msg, name, DNS_SECTION_ADDITIONAL);
                name = next;
        }

        return (ISC_R_SUCCESS);

 failure:

        if (dynbuf != NULL)
                isc_buffer_free(&dynbuf);
        return (result);
}

isc_result_t
dns_tkey_buildgssquery(dns_message_t *msg, dns_name_t *name, dns_name_t *gname,
                       isc_buffer_t *intoken, isc_uint32_t lifetime,
                       gss_ctx_id_t *context, isc_boolean_t win2k,
                       isc_mem_t *mctx, char **err_message)
{
        dns_rdata_tkey_t tkey;
        isc_result_t result;
        isc_stdtime_t now;
        isc_buffer_t token;
        unsigned char array[4096];

        UNUSED(intoken);

        REQUIRE(msg != NULL);
        REQUIRE(name != NULL);
        REQUIRE(gname != NULL);
        REQUIRE(context != NULL);
        REQUIRE(mctx != NULL);

        isc_buffer_init(&token, array, sizeof(array));
        result = dst_gssapi_initctx(gname, NULL, &token, context,
                                    mctx, err_message);
        if (result != DNS_R_CONTINUE && result != ISC_R_SUCCESS)
                return (result);

        tkey.common.rdclass = dns_rdataclass_any;
        tkey.common.rdtype = dns_rdatatype_tkey;
        ISC_LINK_INIT(&tkey.common, link);
        tkey.mctx = NULL;
        dns_name_init(&tkey.algorithm, NULL);

        if (win2k)
                dns_name_clone(DNS_TSIG_GSSAPIMS_NAME, &tkey.algorithm);
        else
                dns_name_clone(DNS_TSIG_GSSAPI_NAME, &tkey.algorithm);

        isc_stdtime_get(&now);
        tkey.inception = now;
        tkey.expire = now + lifetime;
        tkey.mode = DNS_TKEYMODE_GSSAPI;
        tkey.error = 0;
        tkey.key = isc_buffer_base(&token);
        tkey.keylen = isc_buffer_usedlength(&token);
        tkey.other = NULL;
        tkey.otherlen = 0;

        RETERR(buildquery(msg, name, &tkey, win2k));

        return (ISC_R_SUCCESS);

 failure:
        return (result);
}

isc_result_t
dns_tkey_builddeletequery(dns_message_t *msg, dns_tsigkey_t *key) {
        dns_rdata_tkey_t tkey;

        REQUIRE(msg != NULL);
        REQUIRE(key != NULL);

        tkey.common.rdclass = dns_rdataclass_any;
        tkey.common.rdtype = dns_rdatatype_tkey;
        ISC_LINK_INIT(&tkey.common, link);
        tkey.mctx = msg->mctx;
        dns_name_init(&tkey.algorithm, NULL);
        dns_name_clone(key->algorithm, &tkey.algorithm);
        tkey.inception = tkey.expire = 0;
        tkey.mode = DNS_TKEYMODE_DELETE;
        tkey.error = 0;
        tkey.keylen = tkey.otherlen = 0;
        tkey.key = tkey.other = NULL;

        return (buildquery(msg, &key->name, &tkey, ISC_FALSE));
}

static isc_result_t
find_tkey(dns_message_t *msg, dns_name_t **name, dns_rdata_t *rdata,
          int section)
{
        dns_rdataset_t *tkeyset;
        isc_result_t result;

        result = dns_message_firstname(msg, section);
        while (result == ISC_R_SUCCESS) {
                *name = NULL;
                dns_message_currentname(msg, section, name);
                tkeyset = NULL;
                result = dns_message_findtype(*name, dns_rdatatype_tkey, 0,
                                              &tkeyset);
                if (result == ISC_R_SUCCESS) {
                        result = dns_rdataset_first(tkeyset);
                        if (result != ISC_R_SUCCESS)
                                return (result);
                        dns_rdataset_current(tkeyset, rdata);
                        return (ISC_R_SUCCESS);
                }
                result = dns_message_nextname(msg, section);
        }
        if (result == ISC_R_NOMORE)
                return (ISC_R_NOTFOUND);
        return (result);
}

isc_result_t
dns_tkey_processdhresponse(dns_message_t *qmsg, dns_message_t *rmsg,
                           dst_key_t *key, isc_buffer_t *nonce,
                           dns_tsigkey_t **outkey, dns_tsig_keyring_t *ring)
{
        dns_rdata_t qtkeyrdata = DNS_RDATA_INIT, rtkeyrdata = DNS_RDATA_INIT;
        dns_name_t keyname, *tkeyname, *theirkeyname, *ourkeyname, *tempname;
        dns_rdataset_t *theirkeyset = NULL, *ourkeyset = NULL;
        dns_rdata_t theirkeyrdata = DNS_RDATA_INIT;
        dst_key_t *theirkey = NULL;
        dns_rdata_tkey_t qtkey, rtkey;
        unsigned char secretdata[256];
        unsigned int sharedsize;
        isc_buffer_t *shared = NULL, secret;
        isc_region_t r, r2;
        isc_result_t result;
        isc_boolean_t freertkey = ISC_FALSE;

        REQUIRE(qmsg != NULL);
        REQUIRE(rmsg != NULL);
        REQUIRE(key != NULL);
        REQUIRE(dst_key_alg(key) == DNS_KEYALG_DH);
        REQUIRE(dst_key_isprivate(key));
        if (outkey != NULL)
                REQUIRE(*outkey == NULL);

        if (rmsg->rcode != dns_rcode_noerror)
                return (ISC_RESULTCLASS_DNSRCODE + rmsg->rcode);
        RETERR(find_tkey(rmsg, &tkeyname, &rtkeyrdata, DNS_SECTION_ANSWER));
        RETERR(dns_rdata_tostruct(&rtkeyrdata, &rtkey, NULL));
        freertkey = ISC_TRUE;

        RETERR(find_tkey(qmsg, &tempname, &qtkeyrdata,
                         DNS_SECTION_ADDITIONAL));
        RETERR(dns_rdata_tostruct(&qtkeyrdata, &qtkey, NULL));

        if (rtkey.error != dns_rcode_noerror ||
            rtkey.mode != DNS_TKEYMODE_DIFFIEHELLMAN ||
            rtkey.mode != qtkey.mode ||
            !dns_name_equal(&rtkey.algorithm, &qtkey.algorithm) ||
            rmsg->rcode != dns_rcode_noerror) {
                tkey_log("dns_tkey_processdhresponse: tkey mode invalid "
                         "or error set(1)");
                result = DNS_R_INVALIDTKEY;
                dns_rdata_freestruct(&qtkey);
                goto failure;
        }

        dns_rdata_freestruct(&qtkey);

        dns_name_init(&keyname, NULL);
        dns_name_clone(dst_key_name(key), &keyname);

        ourkeyname = NULL;
        ourkeyset = NULL;
        RETERR(dns_message_findname(rmsg, DNS_SECTION_ANSWER, &keyname,
                                    dns_rdatatype_key, 0, &ourkeyname,
                                    &ourkeyset));

        result = dns_message_firstname(rmsg, DNS_SECTION_ANSWER);
        while (result == ISC_R_SUCCESS) {
                theirkeyname = NULL;
                dns_message_currentname(rmsg, DNS_SECTION_ANSWER,
                                        &theirkeyname);
                if (dns_name_equal(theirkeyname, ourkeyname))
                        goto next;
                theirkeyset = NULL;
                result = dns_message_findtype(theirkeyname, dns_rdatatype_key,
                                              0, &theirkeyset);
                if (result == ISC_R_SUCCESS) {
                        RETERR(dns_rdataset_first(theirkeyset));
                        break;
                }
 next:
                result = dns_message_nextname(rmsg, DNS_SECTION_ANSWER);
        }

        if (theirkeyset == NULL) {
                tkey_log("dns_tkey_processdhresponse: failed to find server "
                         "key");
                result = ISC_R_NOTFOUND;
                goto failure;
        }

        dns_rdataset_current(theirkeyset, &theirkeyrdata);
        RETERR(dns_dnssec_keyfromrdata(theirkeyname, &theirkeyrdata,
                                       rmsg->mctx, &theirkey));

        RETERR(dst_key_secretsize(key, &sharedsize));
        RETERR(isc_buffer_allocate(rmsg->mctx, &shared, sharedsize));

        RETERR(dst_key_computesecret(theirkey, key, shared));

        isc_buffer_init(&secret, secretdata, sizeof(secretdata));

        r.base = rtkey.key;
        r.length = rtkey.keylen;
        if (nonce != NULL)
                isc_buffer_usedregion(nonce, &r2);
        else {
                r2.base = isc_mem_get(rmsg->mctx, 0);
                r2.length = 0;
        }
        RETERR(compute_secret(shared, &r2, &r, &secret));
        if (nonce == NULL)
                isc_mem_put(rmsg->mctx, r2.base, 0);

        isc_buffer_usedregion(&secret, &r);
        result = dns_tsigkey_create(tkeyname, &rtkey.algorithm,
                                    r.base, r.length, ISC_TRUE,
                                    NULL, rtkey.inception, rtkey.expire,
                                    rmsg->mctx, ring, outkey);
        isc_buffer_free(&shared);
        dns_rdata_freestruct(&rtkey);
        dst_key_free(&theirkey);
        return (result);

 failure:
        if (shared != NULL)
                isc_buffer_free(&shared);

        if (theirkey != NULL)
                dst_key_free(&theirkey);

        if (freertkey)
                dns_rdata_freestruct(&rtkey);

        return (result);
}

isc_result_t
dns_tkey_processgssresponse(dns_message_t *qmsg, dns_message_t *rmsg,
                            dns_name_t *gname, gss_ctx_id_t *context,
                            isc_buffer_t *outtoken, dns_tsigkey_t **outkey,
                            dns_tsig_keyring_t *ring, char **err_message)
{
        dns_rdata_t rtkeyrdata = DNS_RDATA_INIT, qtkeyrdata = DNS_RDATA_INIT;
        dns_name_t *tkeyname;
        dns_rdata_tkey_t rtkey, qtkey;
        dst_key_t *dstkey = NULL;
        isc_buffer_t intoken;
        isc_result_t result;
        unsigned char array[1024];

        REQUIRE(outtoken != NULL);
        REQUIRE(qmsg != NULL);
        REQUIRE(rmsg != NULL);
        REQUIRE(gname != NULL);
        REQUIRE(ring != NULL);
        if (outkey != NULL)
                REQUIRE(*outkey == NULL);

        if (rmsg->rcode != dns_rcode_noerror)
                return (ISC_RESULTCLASS_DNSRCODE + rmsg->rcode);
        RETERR(find_tkey(rmsg, &tkeyname, &rtkeyrdata, DNS_SECTION_ANSWER));
        RETERR(dns_rdata_tostruct(&rtkeyrdata, &rtkey, NULL));

        /*
         * Win2k puts the item in the ANSWER section, while the RFC
         * specifies it should be in the ADDITIONAL section.  Check first
         * where it should be, and then where it may be.
         */
        result = find_tkey(qmsg, &tkeyname, &qtkeyrdata,
                           DNS_SECTION_ADDITIONAL);
        if (result == ISC_R_NOTFOUND)
                result = find_tkey(qmsg, &tkeyname, &qtkeyrdata,
                                   DNS_SECTION_ANSWER);
        if (result != ISC_R_SUCCESS)
                goto failure;

        RETERR(dns_rdata_tostruct(&qtkeyrdata, &qtkey, NULL));

        if (rtkey.error != dns_rcode_noerror ||
            rtkey.mode != DNS_TKEYMODE_GSSAPI ||
            !dns_name_equal(&rtkey.algorithm, &qtkey.algorithm)) {
                tkey_log("dns_tkey_processgssresponse: tkey mode invalid "
                         "or error set(2) %d", rtkey.error);
                _dns_tkey_dumpmessage(qmsg);
                _dns_tkey_dumpmessage(rmsg);
                result = DNS_R_INVALIDTKEY;
                goto failure;
        }

        isc_buffer_init(outtoken, array, sizeof(array));
        isc_buffer_init(&intoken, rtkey.key, rtkey.keylen);
        RETERR(dst_gssapi_initctx(gname, &intoken, outtoken, context,
                                  ring->mctx, err_message));

        RETERR(dst_key_fromgssapi(dns_rootname, *context, rmsg->mctx,
                                  &dstkey, NULL));

        RETERR(dns_tsigkey_createfromkey(tkeyname, DNS_TSIG_GSSAPI_NAME,
                                         dstkey, ISC_FALSE, NULL,
                                         rtkey.inception, rtkey.expire,
                                         ring->mctx, ring, outkey));
        dst_key_free(&dstkey);
        dns_rdata_freestruct(&rtkey);
        return (result);

 failure:
        /*
         * XXXSRA This probably leaks memory from rtkey and qtkey.
         */
        if (dstkey != NULL)
                dst_key_free(&dstkey);
        return (result);
}

isc_result_t
dns_tkey_processdeleteresponse(dns_message_t *qmsg, dns_message_t *rmsg,
                               dns_tsig_keyring_t *ring)
{
        dns_rdata_t qtkeyrdata = DNS_RDATA_INIT, rtkeyrdata = DNS_RDATA_INIT;
        dns_name_t *tkeyname, *tempname;
        dns_rdata_tkey_t qtkey, rtkey;
        dns_tsigkey_t *tsigkey = NULL;
        isc_result_t result;

        REQUIRE(qmsg != NULL);
        REQUIRE(rmsg != NULL);

        if (rmsg->rcode != dns_rcode_noerror)
                return(ISC_RESULTCLASS_DNSRCODE + rmsg->rcode);

        RETERR(find_tkey(rmsg, &tkeyname, &rtkeyrdata, DNS_SECTION_ANSWER));
        RETERR(dns_rdata_tostruct(&rtkeyrdata, &rtkey, NULL));

        RETERR(find_tkey(qmsg, &tempname, &qtkeyrdata,
                         DNS_SECTION_ADDITIONAL));
        RETERR(dns_rdata_tostruct(&qtkeyrdata, &qtkey, NULL));

        if (rtkey.error != dns_rcode_noerror ||
            rtkey.mode != DNS_TKEYMODE_DELETE ||
            rtkey.mode != qtkey.mode ||
            !dns_name_equal(&rtkey.algorithm, &qtkey.algorithm) ||
            rmsg->rcode != dns_rcode_noerror) {
                tkey_log("dns_tkey_processdeleteresponse: tkey mode invalid "
                         "or error set(3)");
                result = DNS_R_INVALIDTKEY;
                dns_rdata_freestruct(&qtkey);
                dns_rdata_freestruct(&rtkey);
                goto failure;
        }

        dns_rdata_freestruct(&qtkey);

        RETERR(dns_tsigkey_find(&tsigkey, tkeyname, &rtkey.algorithm, ring));

        dns_rdata_freestruct(&rtkey);

        /*
         * Mark the key as deleted.
         */
        dns_tsigkey_setdeleted(tsigkey);
        /*
         * Release the reference.
         */
        dns_tsigkey_detach(&tsigkey);

 failure:
        return (result);
}

isc_result_t
dns_tkey_gssnegotiate(dns_message_t *qmsg, dns_message_t *rmsg,
                      dns_name_t *server, gss_ctx_id_t *context,
                      dns_tsigkey_t **outkey, dns_tsig_keyring_t *ring,
                      isc_boolean_t win2k, char **err_message)
{
        dns_rdata_t rtkeyrdata = DNS_RDATA_INIT, qtkeyrdata = DNS_RDATA_INIT;
        dns_name_t *tkeyname;
        dns_rdata_tkey_t rtkey, qtkey;
        isc_buffer_t intoken, outtoken;
        dst_key_t *dstkey = NULL;
        isc_result_t result;
        unsigned char array[1024];
        isc_boolean_t freertkey = ISC_FALSE;

        REQUIRE(qmsg != NULL);
        REQUIRE(rmsg != NULL);
        REQUIRE(server != NULL);
        if (outkey != NULL)
                REQUIRE(*outkey == NULL);

        if (rmsg->rcode != dns_rcode_noerror)
                return (ISC_RESULTCLASS_DNSRCODE + rmsg->rcode);

        RETERR(find_tkey(rmsg, &tkeyname, &rtkeyrdata, DNS_SECTION_ANSWER));
        RETERR(dns_rdata_tostruct(&rtkeyrdata, &rtkey, NULL));
        freertkey = ISC_TRUE;

        if (win2k == ISC_TRUE)
                RETERR(find_tkey(qmsg, &tkeyname, &qtkeyrdata,
                                 DNS_SECTION_ANSWER));
        else
                RETERR(find_tkey(qmsg, &tkeyname, &qtkeyrdata,
                                 DNS_SECTION_ADDITIONAL));

        RETERR(dns_rdata_tostruct(&qtkeyrdata, &qtkey, NULL));

        if (rtkey.error != dns_rcode_noerror ||
            rtkey.mode != DNS_TKEYMODE_GSSAPI ||
            !dns_name_equal(&rtkey.algorithm, &qtkey.algorithm))
        {
                tkey_log("dns_tkey_processdhresponse: tkey mode invalid "
                         "or error set(4)");
                result = DNS_R_INVALIDTKEY;
                goto failure;
        }

        isc_buffer_init(&intoken, rtkey.key, rtkey.keylen);
        isc_buffer_init(&outtoken, array, sizeof(array));

        result = dst_gssapi_initctx(server, &intoken, &outtoken, context,
                                    ring->mctx, err_message);
        if (result != DNS_R_CONTINUE && result != ISC_R_SUCCESS)
                return (result);

        RETERR(dst_key_fromgssapi(dns_rootname, *context, rmsg->mctx,
                                  &dstkey, NULL));

        /*
         * XXXSRA This seems confused.  If we got CONTINUE from initctx,
         * the GSS negotiation hasn't completed yet, so we can't sign
         * anything yet.
         */

        RETERR(dns_tsigkey_createfromkey(tkeyname,
                                         (win2k
                                          ? DNS_TSIG_GSSAPIMS_NAME
                                          : DNS_TSIG_GSSAPI_NAME),
                                         dstkey, ISC_TRUE, NULL,
                                         rtkey.inception, rtkey.expire,
                                         ring->mctx, ring, outkey));
        dst_key_free(&dstkey);
        dns_rdata_freestruct(&rtkey);
        return (result);

 failure:
        /*
         * XXXSRA This probably leaks memory from qtkey.
         */
        if (freertkey)
                dns_rdata_freestruct(&rtkey);
        if (dstkey != NULL)
                dst_key_free(&dstkey);
        return (result);
}

---