/*
 * validator/val_sigcrypt.c - validator signature crypto functions.
 *
 * Copyright (c) 2007, NLnet Labs. All rights reserved.
 *
 * This software is open source.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 * 
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 * 
 * Neither the name of the NLNET LABS nor the names of its contributors may
 * be used to endorse or promote products derived from this software without
 * specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/**
 * \file
 *
 * This file contains helper functions for the validator module.
 * The functions help with signature verification and checking, the
 * bridging between RR wireformat data and crypto calls.
 */
#include "config.h"
#include "validator/val_sigcrypt.h"
#include "validator/val_secalgo.h"
#include "validator/validator.h"
#include "util/data/msgreply.h"
#include "util/data/msgparse.h"
#include "util/data/dname.h"
#include "util/rbtree.h"
#include "util/rfc_1982.h"
#include "util/module.h"
#include "util/net_help.h"
#include "util/regional.h"
#include "util/config_file.h"
#include "sldns/keyraw.h"
#include "sldns/sbuffer.h"
#include "sldns/parseutil.h"
#include "sldns/wire2str.h"
#include "services/mesh.h"

#include <ctype.h>
#if !defined(HAVE_SSL) && !defined(HAVE_NSS) && !defined(HAVE_NETTLE)
#error "Need crypto library to do digital signature cryptography"
#endif

#ifdef HAVE_OPENSSL_ERR_H
#include <openssl/err.h>
#endif

#ifdef HAVE_OPENSSL_RAND_H
#include <openssl/rand.h>
#endif

#ifdef HAVE_OPENSSL_CONF_H
#include <openssl/conf.h>
#endif

#ifdef HAVE_OPENSSL_ENGINE_H
#include <openssl/engine.h>
#endif

/** Maximum number of RRSIG validations for an RRset. */
#define MAX_VALIDATE_RRSIGS 8

/** return number of rrs in an rrset */
static size_t
rrset_get_count(struct ub_packed_rrset_key* rrset)
{
        struct packed_rrset_data* d = (struct packed_rrset_data*)
        rrset->entry.data;
        if(!d) return 0;
        return d->count;
}

/**
 * Get RR signature count
 */
static size_t
rrset_get_sigcount(struct ub_packed_rrset_key* k)
{
        struct packed_rrset_data* d = (struct packed_rrset_data*)k->entry.data;
        return d->rrsig_count;
}

/**
 * Get signature keytag value
 * @param k: rrset (with signatures)
 * @param sig_idx: signature index.
 * @return keytag or 0 if malformed rrsig.
 */
static uint16_t 
rrset_get_sig_keytag(struct ub_packed_rrset_key* k, size_t sig_idx)
{
        uint16_t t;
        struct packed_rrset_data* d = (struct packed_rrset_data*)k->entry.data;
        log_assert(sig_idx < d->rrsig_count);
        if(d->rr_len[d->count + sig_idx] < 2+18)
                return 0;
        memmove(&t, d->rr_data[d->count + sig_idx]+2+16, 2);
        return ntohs(t);
}

/**
 * Get signature signing algorithm value
 * @param k: rrset (with signatures)
 * @param sig_idx: signature index.
 * @return algo or 0 if malformed rrsig.
 */
static int 
rrset_get_sig_algo(struct ub_packed_rrset_key* k, size_t sig_idx)
{
        struct packed_rrset_data* d = (struct packed_rrset_data*)k->entry.data;
        log_assert(sig_idx < d->rrsig_count);
        if(d->rr_len[d->count + sig_idx] < 2+3)
                return 0;
        return (int)d->rr_data[d->count + sig_idx][2+2];
}

/** get rdata pointer and size */
static void
rrset_get_rdata(struct ub_packed_rrset_key* k, size_t idx, uint8_t** rdata,
        size_t* len)
{
        struct packed_rrset_data* d = (struct packed_rrset_data*)k->entry.data;
        log_assert(d && idx < (d->count + d->rrsig_count));
        *rdata = d->rr_data[idx];
        *len = d->rr_len[idx];
}

uint16_t
dnskey_get_flags(struct ub_packed_rrset_key* k, size_t idx)
{
        uint8_t* rdata;
        size_t len;
        uint16_t f;
        rrset_get_rdata(k, idx, &rdata, &len);
        if(len < 2+2)
                return 0;
        memmove(&f, rdata+2, 2);
        f = ntohs(f);
        return f;
}

/**
 * Get DNSKEY protocol value from rdata
 * @param k: DNSKEY rrset.
 * @param idx: which key.
 * @return protocol octet value
 */
static int
dnskey_get_protocol(struct ub_packed_rrset_key* k, size_t idx)
{
        uint8_t* rdata;
        size_t len;
        rrset_get_rdata(k, idx, &rdata, &len);
        if(len < 2+4)
                return 0;
        return (int)rdata[2+2];
}

int
dnskey_get_algo(struct ub_packed_rrset_key* k, size_t idx)
{
        uint8_t* rdata;
        size_t len;
        rrset_get_rdata(k, idx, &rdata, &len);
        if(len < 2+4)
                return 0;
        return (int)rdata[2+3];
}

/** get public key rdata field from a dnskey RR and do some checks */
static void
dnskey_get_pubkey(struct ub_packed_rrset_key* k, size_t idx,
        unsigned char** pk, unsigned int* pklen)
{
        uint8_t* rdata;
        size_t len;
        rrset_get_rdata(k, idx, &rdata, &len);
        if(len < 2+5) {
                *pk = NULL;
                *pklen = 0;
                return;
        }
        *pk = (unsigned char*)rdata+2+4;
        *pklen = (unsigned)len-2-4;
}

int
ds_get_key_algo(struct ub_packed_rrset_key* k, size_t idx)
{
        uint8_t* rdata;
        size_t len;
        rrset_get_rdata(k, idx, &rdata, &len);
        if(len < 2+3)
                return 0;
        return (int)rdata[2+2];
}

int
ds_get_digest_algo(struct ub_packed_rrset_key* k, size_t idx)
{
        uint8_t* rdata;
        size_t len;
        rrset_get_rdata(k, idx, &rdata, &len);
        if(len < 2+4)
                return 0;
        return (int)rdata[2+3];
}

uint16_t 
ds_get_keytag(struct ub_packed_rrset_key* ds_rrset, size_t ds_idx)
{
        uint16_t t;
        uint8_t* rdata;
        size_t len;
        rrset_get_rdata(ds_rrset, ds_idx, &rdata, &len);
        if(len < 2+2)
                return 0;
        memmove(&t, rdata+2, 2);
        return ntohs(t);
}

/**
 * Return pointer to the digest in a DS RR.
 * @param k: DS rrset.
 * @param idx: which DS.
 * @param digest: digest data is returned.
 *      on error, this is NULL.
 * @param len: length of digest is returned.
 *      on error, the length is 0.
 */
static void
ds_get_sigdata(struct ub_packed_rrset_key* k, size_t idx, uint8_t** digest,
        size_t* len)
{
        uint8_t* rdata;
        size_t rdlen;
        rrset_get_rdata(k, idx, &rdata, &rdlen);
        if(rdlen < 2+5) {
                *digest = NULL;
                *len = 0;
                return;
        }
        *digest = rdata + 2 + 4;
        *len = rdlen - 2 - 4;
}

/**
 * Return size of DS digest according to its hash algorithm.
 * @param k: DS rrset.
 * @param idx: which DS.
 * @return size in bytes of digest, or 0 if not supported. 
 */
static size_t
ds_digest_size_algo(struct ub_packed_rrset_key* k, size_t idx)
{
        return ds_digest_size_supported(ds_get_digest_algo(k, idx));
}

/**
 * Create a DS digest for a DNSKEY entry.
 *
 * @param env: module environment. Uses scratch space.
 * @param dnskey_rrset: DNSKEY rrset.
 * @param dnskey_idx: index of RR in rrset.
 * @param ds_rrset: DS rrset
 * @param ds_idx: index of RR in DS rrset.
 * @param digest: digest is returned in here (must be correctly sized).
 * @return false on error.
 */
static int
ds_create_dnskey_digest(struct module_env* env, 
        struct ub_packed_rrset_key* dnskey_rrset, size_t dnskey_idx,
        struct ub_packed_rrset_key* ds_rrset, size_t ds_idx,
        uint8_t* digest)
{
        sldns_buffer* b = env->scratch_buffer;
        uint8_t* dnskey_rdata;
        size_t dnskey_len;
        rrset_get_rdata(dnskey_rrset, dnskey_idx, &dnskey_rdata, &dnskey_len);

        /* create digest source material in buffer 
         * digest = digest_algorithm( DNSKEY owner name | DNSKEY RDATA);
         *      DNSKEY RDATA = Flags | Protocol | Algorithm | Public Key. */
        sldns_buffer_clear(b);
        sldns_buffer_write(b, dnskey_rrset->rk.dname, 
                dnskey_rrset->rk.dname_len);
        query_dname_tolower(sldns_buffer_begin(b));
        sldns_buffer_write(b, dnskey_rdata+2, dnskey_len-2); /* skip rdatalen*/
        sldns_buffer_flip(b);
        
        return secalgo_ds_digest(ds_get_digest_algo(ds_rrset, ds_idx),
                (unsigned char*)sldns_buffer_begin(b), sldns_buffer_limit(b),
                (unsigned char*)digest);
}

int ds_digest_match_dnskey(struct module_env* env,
        struct ub_packed_rrset_key* dnskey_rrset, size_t dnskey_idx,
        struct ub_packed_rrset_key* ds_rrset, size_t ds_idx)
{
        uint8_t* ds;    /* DS digest */
        size_t dslen;
        uint8_t* digest; /* generated digest */
        size_t digestlen = ds_digest_size_algo(ds_rrset, ds_idx);

        if(digestlen == 0) {
                verbose(VERB_QUERY, "DS fail: not supported, or DS RR "
                        "format error");
                return 0; /* not supported, or DS RR format error */
        }
#ifndef USE_SHA1
        if(fake_sha1 && ds_get_digest_algo(ds_rrset, ds_idx)==LDNS_SHA1)
                return 1;
#endif
        
        /* check digest length in DS with length from hash function */
        ds_get_sigdata(ds_rrset, ds_idx, &ds, &dslen);
        if(!ds || dslen != digestlen) {
                verbose(VERB_QUERY, "DS fail: DS RR algo and digest do not "
                        "match each other");
                return 0; /* DS algorithm and digest do not match */
        }

        digest = regional_alloc(env->scratch, digestlen);
        if(!digest) {
                verbose(VERB_QUERY, "DS fail: out of memory");
                return 0; /* mem error */
        }
        if(!ds_create_dnskey_digest(env, dnskey_rrset, dnskey_idx, ds_rrset, 
                ds_idx, digest)) {
                verbose(VERB_QUERY, "DS fail: could not calc key digest");
                return 0; /* digest algo failed */
        }
        if(memcmp(digest, ds, dslen) != 0) {
                verbose(VERB_QUERY, "DS fail: digest is different");
                return 0; /* digest different */
        }
        return 1;
}

int 
ds_digest_algo_is_supported(struct ub_packed_rrset_key* ds_rrset, 
        size_t ds_idx)
{
        return (ds_digest_size_algo(ds_rrset, ds_idx) != 0);
}

int 
ds_key_algo_is_supported(struct ub_packed_rrset_key* ds_rrset, 
        size_t ds_idx)
{
        return dnskey_algo_id_is_supported(ds_get_key_algo(ds_rrset, ds_idx));
}

uint16_t 
dnskey_calc_keytag(struct ub_packed_rrset_key* dnskey_rrset, size_t dnskey_idx)
{
        uint8_t* data;
        size_t len;
        rrset_get_rdata(dnskey_rrset, dnskey_idx, &data, &len);
        /* do not pass rdatalen to ldns */
        return sldns_calc_keytag_raw(data+2, len-2);
}

int dnskey_algo_is_supported(struct ub_packed_rrset_key* dnskey_rrset,
        size_t dnskey_idx)
{
        return dnskey_algo_id_is_supported(dnskey_get_algo(dnskey_rrset, 
                dnskey_idx));
}

int dnskey_size_is_supported(struct ub_packed_rrset_key* dnskey_rrset,
        size_t dnskey_idx)
{
#ifdef DEPRECATE_RSA_1024
        uint8_t* rdata;
        size_t len;
        int alg = dnskey_get_algo(dnskey_rrset, dnskey_idx);
        size_t keysize;

        rrset_get_rdata(dnskey_rrset, dnskey_idx, &rdata, &len);
        if(len < 2+4)
                return 0;
        keysize = sldns_rr_dnskey_key_size_raw(rdata+2+4, len-2-4, alg);

        switch((sldns_algorithm)alg) {
        case LDNS_RSAMD5:
        case LDNS_RSASHA1:
        case LDNS_RSASHA1_NSEC3:
        case LDNS_RSASHA256:
        case LDNS_RSASHA512:
                /* reject RSA keys of 1024 bits and shorter */
                if(keysize <= 1024)
                        return 0;
                break;
        default:
                break;
        }
#else
        (void)dnskey_rrset; (void)dnskey_idx;
#endif /* DEPRECATE_RSA_1024 */
        return 1;
}

int dnskeyset_size_is_supported(struct ub_packed_rrset_key* dnskey_rrset)
{
        size_t i, num = rrset_get_count(dnskey_rrset);
        for(i=0; i<num; i++) {
                if(!dnskey_size_is_supported(dnskey_rrset, i))
                        return 0;
        }
        return 1;
}

void algo_needs_init_dnskey_add(struct algo_needs* n,
        struct ub_packed_rrset_key* dnskey, uint8_t* sigalg)
{
        uint8_t algo;
        size_t i, total = n->num;
        size_t num = rrset_get_count(dnskey);

        for(i=0; i<num; i++) {
                algo = (uint8_t)dnskey_get_algo(dnskey, i);
                if(!dnskey_algo_id_is_supported((int)algo))
                        continue;
                if(n->needs[algo] == 0) {
                        n->needs[algo] = 1;
                        sigalg[total] = algo;
                        total++;
                }
        }
        sigalg[total] = 0;
        n->num = total;
}

void algo_needs_init_list(struct algo_needs* n, uint8_t* sigalg)
{
        uint8_t algo;
        size_t total = 0;

        memset(n->needs, 0, sizeof(uint8_t)*ALGO_NEEDS_MAX);
        while( (algo=*sigalg++) != 0) {
                log_assert(dnskey_algo_id_is_supported((int)algo));
                log_assert(n->needs[algo] == 0);
                n->needs[algo] = 1;
                total++;
        }
        n->num = total;
}

void algo_needs_init_ds(struct algo_needs* n, struct ub_packed_rrset_key* ds,
        int fav_ds_algo, uint8_t* sigalg)
{
        uint8_t algo;
        size_t i, total = 0;
        size_t num = rrset_get_count(ds);

        memset(n->needs, 0, sizeof(uint8_t)*ALGO_NEEDS_MAX);
        for(i=0; i<num; i++) {
                if(ds_get_digest_algo(ds, i) != fav_ds_algo)
                        continue;
                algo = (uint8_t)ds_get_key_algo(ds, i);
                if(!dnskey_algo_id_is_supported((int)algo))
                        continue;
                log_assert(algo != 0); /* we do not support 0 and is EOS */
                if(n->needs[algo] == 0) {
                        n->needs[algo] = 1;
                        sigalg[total] = algo;           
                        total++;
                }
        }
        sigalg[total] = 0;
        n->num = total;
}

int algo_needs_set_secure(struct algo_needs* n, uint8_t algo)
{
        if(n->needs[algo]) {
                n->needs[algo] = 0;
                n->num --;
                if(n->num == 0) /* done! */
                        return 1;
        }
        return 0;
}

void algo_needs_set_bogus(struct algo_needs* n, uint8_t algo)
{
        if(n->needs[algo]) n->needs[algo] = 2; /* need it, but bogus */
}

size_t algo_needs_num_missing(struct algo_needs* n)
{
        return n->num;
}

int algo_needs_missing(struct algo_needs* n)
{
        int i, miss = -1;
        /* check if a needed algo was bogus - report that;
         * check the first missing algo - report that;
         * or return 0 */
        for(i=0; i<ALGO_NEEDS_MAX; i++) {
                if(n->needs[i] == 2)
                        return 0;
                if(n->needs[i] == 1 && miss == -1)
                        miss = i;
        }
        if(miss != -1) return miss;
        return 0;
}

/**
 * verify rrset, with dnskey rrset, for a specific rrsig in rrset
 * @param env: module environment, scratch space is used.
 * @param ve: validator environment, date settings.
 * @param now: current time for validation (can be overridden).
 * @param rrset: to be validated.
 * @param dnskey: DNSKEY rrset, keyset to try.
 * @param sig_idx: which signature to try to validate.
 * @param sortree: reused sorted order. Stored in region. Pass NULL at start,
 *      and for a new rrset.
 * @param reason: if bogus, a string returned, fixed or alloced in scratch.
 * @param reason_bogus: EDE (RFC8914) code paired with the reason of failure.
 * @param section: section of packet where this rrset comes from.
 * @param qstate: qstate with region.
 * @param numverified: incremented when the number of RRSIG validations
 *      increases.
 * @return secure if any key signs *this* signature. bogus if no key signs it,
 *      unchecked on error, or indeterminate if all keys are not supported by
 *      the crypto library (openssl3+ only).
 */
static enum sec_status
dnskeyset_verify_rrset_sig(struct module_env* env, struct val_env* ve,
        time_t now, struct ub_packed_rrset_key* rrset,
        struct ub_packed_rrset_key* dnskey, size_t sig_idx,
        struct rbtree_type** sortree,
        char** reason, sldns_ede_code *reason_bogus,
        sldns_pkt_section section, struct module_qstate* qstate,
        int* numverified)
{
        /* find matching keys and check them */
        enum sec_status sec = sec_status_bogus;
        uint16_t tag = rrset_get_sig_keytag(rrset, sig_idx);
        int algo = rrset_get_sig_algo(rrset, sig_idx);
        size_t i, num = rrset_get_count(dnskey);
        size_t numchecked = 0;
        size_t numindeterminate = 0;
        int buf_canon = 0;
        verbose(VERB_ALGO, "verify sig %d %d", (int)tag, algo);
        if(!dnskey_algo_id_is_supported(algo)) {
                if(reason_bogus)
                        *reason_bogus = LDNS_EDE_UNSUPPORTED_DNSKEY_ALG;
                verbose(VERB_QUERY, "verify sig: unknown algorithm");
                return sec_status_insecure;
        }

        for(i=0; i<num; i++) {
                /* see if key matches keytag and algo */
                if(algo != dnskey_get_algo(dnskey, i) ||
                        tag != dnskey_calc_keytag(dnskey, i))
                        continue;
                numchecked ++;
                (*numverified)++;

                /* see if key verifies */
                sec = dnskey_verify_rrset_sig(env->scratch,
                        env->scratch_buffer, ve, now, rrset, dnskey, i,
                        sig_idx, sortree, &buf_canon, reason, reason_bogus,
                        section, qstate);
                if(sec == sec_status_secure)
                        return sec;
                else if(sec == sec_status_indeterminate)
                        numindeterminate ++;
                if(*numverified > MAX_VALIDATE_RRSIGS) {
                        *reason = "too many RRSIG validations";
                        if(reason_bogus)
                                *reason_bogus = LDNS_EDE_DNSSEC_BOGUS;
                        verbose(VERB_ALGO, "verify sig: too many RRSIG validations");
                        return sec_status_bogus;
                }
        }
        if(numchecked == 0) {
                *reason = "signatures from unknown keys";
                if(reason_bogus)
                        *reason_bogus = LDNS_EDE_DNSKEY_MISSING;
                verbose(VERB_QUERY, "verify: could not find appropriate key");
                return sec_status_bogus;
        }
        if(numindeterminate == numchecked) {
                *reason = "unsupported algorithm by crypto library";
                if(reason_bogus)
                        *reason_bogus = LDNS_EDE_UNSUPPORTED_DNSKEY_ALG;
                verbose(VERB_ALGO, "verify sig: unsupported algorithm by "
                        "crypto library");
                return sec_status_indeterminate;
        }
        return sec_status_bogus;
}

enum sec_status 
dnskeyset_verify_rrset(struct module_env* env, struct val_env* ve,
        struct ub_packed_rrset_key* rrset, struct ub_packed_rrset_key* dnskey,
        uint8_t* sigalg, char** reason, sldns_ede_code *reason_bogus,
        sldns_pkt_section section, struct module_qstate* qstate, int* verified,
        char* reasonbuf, size_t reasonlen)
{
        enum sec_status sec;
        size_t i, num;
        rbtree_type* sortree = NULL;
        /* make sure that for all DNSKEY algorithms there are valid sigs */
        struct algo_needs needs;
        int alg;
        *verified = 0;

        num = rrset_get_sigcount(rrset);
        if(num == 0) {
                verbose(VERB_QUERY, "rrset failed to verify due to a lack of "
                        "signatures");
                *reason = "no signatures";
                if(reason_bogus)
                        *reason_bogus = LDNS_EDE_RRSIGS_MISSING;
                return sec_status_bogus;
        }

        if(sigalg) {
                algo_needs_init_list(&needs, sigalg);
                if(algo_needs_num_missing(&needs) == 0) {
                        verbose(VERB_QUERY, "zone has no known algorithms");
                        *reason = "zone has no known algorithms";
                        if(reason_bogus)
                                *reason_bogus = LDNS_EDE_UNSUPPORTED_DNSKEY_ALG;
                        return sec_status_insecure;
                }
        }
        for(i=0; i<num; i++) {
                sec = dnskeyset_verify_rrset_sig(env, ve, *env->now, rrset, 
                        dnskey, i, &sortree, reason, reason_bogus,
                        section, qstate, verified);
                /* see which algorithm has been fixed up */
                if(sec == sec_status_secure) {
                        if(!sigalg)
                                return sec; /* done! */
                        else if(algo_needs_set_secure(&needs,
                                (uint8_t)rrset_get_sig_algo(rrset, i)))
                                return sec; /* done! */
                } else if(sigalg && sec == sec_status_bogus) {
                        algo_needs_set_bogus(&needs,
                                (uint8_t)rrset_get_sig_algo(rrset, i));
                }
                if(*verified > MAX_VALIDATE_RRSIGS) {
                        verbose(VERB_QUERY, "rrset failed to verify, too many RRSIG validations");
                        *reason = "too many RRSIG validations";
                        if(reason_bogus)
                                *reason_bogus = LDNS_EDE_DNSSEC_BOGUS;
                        return sec_status_bogus;
                }
        }
        if(sigalg && (alg=algo_needs_missing(&needs)) != 0) {
                verbose(VERB_ALGO, "rrset failed to verify: "
                        "no valid signatures for %d algorithms",
                        (int)algo_needs_num_missing(&needs));
                algo_needs_reason(alg, reason, "no signatures", reasonbuf,
                        reasonlen);
        } else {
                verbose(VERB_ALGO, "rrset failed to verify: "
                        "no valid signatures");
        }
        return sec_status_bogus;
}

void algo_needs_reason(int alg, char** reason, char* s, char* reasonbuf,
        size_t reasonlen)
{
        sldns_lookup_table *t = sldns_lookup_by_id(sldns_algorithms, alg);
        if(t&&t->name)
                snprintf(reasonbuf, reasonlen, "%s with algorithm %s", s,
                        t->name);
        else    snprintf(reasonbuf, reasonlen, "%s with algorithm ALG%u", s,
                        (unsigned)alg);
        *reason = reasonbuf;
}

enum sec_status
dnskey_verify_rrset(struct module_env* env, struct val_env* ve,
        struct ub_packed_rrset_key* rrset, struct ub_packed_rrset_key* dnskey,
        size_t dnskey_idx, char** reason, sldns_ede_code *reason_bogus,
        sldns_pkt_section section, struct module_qstate* qstate)
{
        enum sec_status sec;
        size_t i, num, numchecked = 0, numindeterminate = 0;
        rbtree_type* sortree = NULL;
        int buf_canon = 0;
        uint16_t tag = dnskey_calc_keytag(dnskey, dnskey_idx);
        int algo = dnskey_get_algo(dnskey, dnskey_idx);
        int numverified = 0;

        num = rrset_get_sigcount(rrset);
        if(num == 0) {
                verbose(VERB_QUERY, "rrset failed to verify due to a lack of "
                        "signatures");
                *reason = "no signatures";
                if(reason_bogus)
                        *reason_bogus = LDNS_EDE_RRSIGS_MISSING;
                return sec_status_bogus;
        }
        for(i=0; i<num; i++) {
                /* see if sig matches keytag and algo */
                if(algo != rrset_get_sig_algo(rrset, i) ||
                        tag != rrset_get_sig_keytag(rrset, i))
                        continue;
                buf_canon = 0;
                sec = dnskey_verify_rrset_sig(env->scratch,
                        env->scratch_buffer, ve, *env->now, rrset, 
                        dnskey, dnskey_idx, i, &sortree, &buf_canon, reason,
                        reason_bogus, section, qstate);
                if(sec == sec_status_secure)
                        return sec;
                numchecked ++;
                numverified ++;
                if(sec == sec_status_indeterminate)
                        numindeterminate ++;
                if(numverified > MAX_VALIDATE_RRSIGS) {
                        verbose(VERB_QUERY, "rrset failed to verify, too many RRSIG validations");
                        *reason = "too many RRSIG validations";
                        if(reason_bogus)
                                *reason_bogus = LDNS_EDE_DNSSEC_BOGUS;
                        return sec_status_bogus;
                }
        }
        if(!numchecked) {
                *reason = "signature for expected key and algorithm missing";
                if(reason_bogus)
                        *reason_bogus = LDNS_EDE_DNSSEC_BOGUS;
        } else if(numchecked == numindeterminate) {
                verbose(VERB_ALGO, "rrset failed to verify due to algorithm "
                        "refusal by cryptolib");
                if(reason_bogus)
                        *reason_bogus = LDNS_EDE_UNSUPPORTED_DNSKEY_ALG;
                *reason = "algorithm refused by cryptolib";
                return sec_status_indeterminate;
        }
        verbose(VERB_ALGO, "rrset failed to verify: all signatures are bogus");
        return sec_status_bogus;
}

/**
 * RR entries in a canonical sorted tree of RRs
 */
struct canon_rr {
        /** rbtree node, key is this structure */
        rbnode_type node;
        /** rrset the RR is in */
        struct ub_packed_rrset_key* rrset;
        /** which RR in the rrset */
        size_t rr_idx;
};

/**
 * Compare two RR for canonical order, in a field-style sweep.
 * @param d: rrset data
 * @param desc: ldns wireformat descriptor.
 * @param i: first RR to compare
 * @param j: first RR to compare
 * @return comparison code.
 */
static int
canonical_compare_byfield(struct packed_rrset_data* d, 
        const sldns_rr_descriptor* desc, size_t i, size_t j)
{
        /* sweep across rdata, keep track of some state:
         *      which rr field, and bytes left in field.
         *      current position in rdata, length left.
         *      are we in a dname, length left in a label.
         */
        int wfi = -1;   /* current wireformat rdata field (rdf) */
        int wfj = -1;
        uint8_t* di = d->rr_data[i]+2; /* ptr to current rdata byte */
        uint8_t* dj = d->rr_data[j]+2;
        size_t ilen = d->rr_len[i]-2; /* length left in rdata */
        size_t jlen = d->rr_len[j]-2;
        int dname_i = 0;  /* true if these bytes are part of a name */
        int dname_j = 0;
        size_t lablen_i = 0; /* 0 for label length byte,for first byte of rdf*/
        size_t lablen_j = 0; /* otherwise remaining length of rdf or label */
        int dname_num_i = (int)desc->_dname_count; /* decreased at root label */
        int dname_num_j = (int)desc->_dname_count;

        /* loop while there are rdata bytes available for both rrs,
         * and still some lowercasing needs to be done; either the dnames
         * have not been reached yet, or they are currently being processed */
        while(ilen > 0 && jlen > 0 && (dname_num_i > 0 || dname_num_j > 0)) {
                /* compare these two bytes */
                /* lowercase if in a dname and not a label length byte */
                if( ((dname_i && lablen_i)?(uint8_t)tolower((int)*di):*di)
                 != ((dname_j && lablen_j)?(uint8_t)tolower((int)*dj):*dj)
                 ) {
                  if(((dname_i && lablen_i)?(uint8_t)tolower((int)*di):*di)
                  < ((dname_j && lablen_j)?(uint8_t)tolower((int)*dj):*dj))
                        return -1;
                    return 1;
                }
                ilen--;
                jlen--;
                /* bytes are equal */

                /* advance field i */
                /* lablen 0 means that this byte is the first byte of the
                 * next rdata field; inspect this rdata field and setup
                 * to process the rest of this rdata field.
                 * The reason to first read the byte, then setup the rdf,
                 * is that we are then sure the byte is available and short
                 * rdata is handled gracefully (even if it is a formerr). */
                if(lablen_i == 0) { 
                        if(dname_i) {
                                /* scan this dname label */
                                /* capture length to lowercase */
                                lablen_i = (size_t)*di;
                                if(lablen_i == 0) {
                                        /* end root label */
                                        dname_i = 0;
                                        dname_num_i--;
                                        /* if dname num is 0, then the
                                         * remainder is binary only */
                                        if(dname_num_i == 0)
                                                lablen_i = ilen;
                                }
                        } else {
                                /* scan this rdata field */
                                wfi++;
                                if(desc->_wireformat[wfi] 
                                        == LDNS_RDF_TYPE_DNAME) {
                                        dname_i = 1; 
                                        lablen_i = (size_t)*di;
                                        if(lablen_i == 0) {
                                                dname_i = 0;
                                                dname_num_i--;
                                                if(dname_num_i == 0)
                                                        lablen_i = ilen;
                                        }
                                } else if(desc->_wireformat[wfi] 
                                        == LDNS_RDF_TYPE_STR)
                                        lablen_i = (size_t)*di;
                                else    lablen_i = get_rdf_size(
                                        desc->_wireformat[wfi]) - 1;
                        }
                } else  lablen_i--;

                /* advance field j; same as for i */
                if(lablen_j == 0) { 
                        if(dname_j) {
                                lablen_j = (size_t)*dj;
                                if(lablen_j == 0) {
                                        dname_j = 0;
                                        dname_num_j--;
                                        if(dname_num_j == 0)
                                                lablen_j = jlen;
                                }
                        } else {
                                wfj++;
                                if(desc->_wireformat[wfj] 
                                        == LDNS_RDF_TYPE_DNAME) {
                                        dname_j = 1; 
                                        lablen_j = (size_t)*dj;
                                        if(lablen_j == 0) {
                                                dname_j = 0;
                                                dname_num_j--;
                                                if(dname_num_j == 0)
                                                        lablen_j = jlen;
                                        }
                                } else if(desc->_wireformat[wfj] 
                                        == LDNS_RDF_TYPE_STR)
                                        lablen_j = (size_t)*dj;
                                else    lablen_j = get_rdf_size(
                                        desc->_wireformat[wfj]) - 1;
                        }
                } else  lablen_j--;
                di++;
                dj++;
        }
        /* end of the loop; because we advanced byte by byte; now we have
         * that the rdata has ended, or that there is a binary remainder */
        /* shortest first */
        if(ilen == 0 && jlen == 0)
                return 0;
        if(ilen == 0)
                return -1;
        if(jlen == 0)
                return 1;
        /* binary remainder, capture comparison in wfi variable */
        if((wfi = memcmp(di, dj, (ilen<jlen)?ilen:jlen)) != 0)
                return wfi;
        if(ilen < jlen)
                return -1;
        if(jlen < ilen)
                return 1;
        return 0;
}

/**
 * Compare two RRs in the same RRset and determine their relative
 * canonical order.
 * @param rrset: the rrset in which to perform compares.
 * @param i: first RR to compare
 * @param j: first RR to compare
 * @return 0 if RR i== RR j, -1 if <, +1 if >.
 */
static int
canonical_compare(struct ub_packed_rrset_key* rrset, size_t i, size_t j)
{
        struct packed_rrset_data* d = (struct packed_rrset_data*)
                rrset->entry.data;
        const sldns_rr_descriptor* desc;
        uint16_t type = ntohs(rrset->rk.type);
        size_t minlen;
        int c;

        if(i==j)
                return 0;

        switch(type) {
                /* These RR types have only a name as RDATA. 
                 * This name has to be canonicalized.*/
                case LDNS_RR_TYPE_NS:
                case LDNS_RR_TYPE_MD:
                case LDNS_RR_TYPE_MF:
                case LDNS_RR_TYPE_CNAME:
                case LDNS_RR_TYPE_MB:
                case LDNS_RR_TYPE_MG:
                case LDNS_RR_TYPE_MR:
                case LDNS_RR_TYPE_PTR:
                case LDNS_RR_TYPE_DNAME:
                        /* the wireread function has already checked these
                         * dname's for correctness, and this double checks */
                        if(!dname_valid(d->rr_data[i]+2, d->rr_len[i]-2) ||
                                !dname_valid(d->rr_data[j]+2, d->rr_len[j]-2))
                                return 0;
                        return query_dname_compare(d->rr_data[i]+2,
                                d->rr_data[j]+2);

                /* These RR types have STR and fixed size rdata fields
                 * before one or more name fields that need canonicalizing,
                 * and after that a byte-for byte remainder can be compared.
                 */
                /* type starts with the name; remainder is binary compared */
                case LDNS_RR_TYPE_NXT: 
                /* use rdata field formats */
                case LDNS_RR_TYPE_MINFO:
                case LDNS_RR_TYPE_RP:
                case LDNS_RR_TYPE_SOA:
                case LDNS_RR_TYPE_RT:
                case LDNS_RR_TYPE_AFSDB:
                case LDNS_RR_TYPE_KX:
                case LDNS_RR_TYPE_MX:
                case LDNS_RR_TYPE_SIG:
                /* RRSIG signer name has to be downcased */
                case LDNS_RR_TYPE_RRSIG:
                case LDNS_RR_TYPE_PX:
                case LDNS_RR_TYPE_NAPTR:
                case LDNS_RR_TYPE_SRV:
                        desc = sldns_rr_descript(type);
                        log_assert(desc);
                        /* this holds for the types that need canonicalizing */
                        log_assert(desc->_minimum == desc->_maximum);
                        return canonical_compare_byfield(d, desc, i, j);

                case LDNS_RR_TYPE_HINFO: /* no longer downcased */
                case LDNS_RR_TYPE_NSEC: 
        default:
                /* For unknown RR types, or types not listed above,
                 * no canonicalization is needed, do binary compare */
                /* byte for byte compare, equal means shortest first*/
                minlen = d->rr_len[i]-2;
                if(minlen > d->rr_len[j]-2)
                        minlen = d->rr_len[j]-2;
                c = memcmp(d->rr_data[i]+2, d->rr_data[j]+2, minlen);
                if(c!=0)
                        return c;
                /* rdata equal, shortest is first */
                if(d->rr_len[i] < d->rr_len[j])
                        return -1;
                if(d->rr_len[i] > d->rr_len[j])
                        return 1;
                /* rdata equal, length equal */
                break;
        }
        return 0;
}

int
canonical_tree_compare(const void* k1, const void* k2)
{
        struct canon_rr* r1 = (struct canon_rr*)k1;
        struct canon_rr* r2 = (struct canon_rr*)k2;
        log_assert(r1->rrset == r2->rrset);
        return canonical_compare(r1->rrset, r1->rr_idx, r2->rr_idx);
}

/**
 * Sort RRs for rrset in canonical order.
 * Does not actually canonicalize the RR rdatas.
 * Does not touch rrsigs.
 * @param rrset: to sort.
 * @param d: rrset data.
 * @param sortree: tree to sort into.
 * @param rrs: rr storage.
 */
static void
canonical_sort(struct ub_packed_rrset_key* rrset, struct packed_rrset_data* d,
        rbtree_type* sortree, struct canon_rr* rrs)
{
        size_t i;
        /* insert into rbtree to sort and detect duplicates */
        for(i=0; i<d->count; i++) {
                rrs[i].node.key = &rrs[i];
                rrs[i].rrset = rrset;
                rrs[i].rr_idx = i;
                if(!rbtree_insert(sortree, &rrs[i].node)) {
                        /* this was a duplicate */
                }
        }
}

/**
 * Insert canonical owner name into buffer.
 * @param buf: buffer to insert into at current position.
 * @param k: rrset with its owner name.
 * @param sig: signature with signer name and label count.
 *      must be length checked, at least 18 bytes long.
 * @param can_owner: position in buffer returned for future use.
 * @param can_owner_len: length of canonical owner name.
 */
static void
insert_can_owner(sldns_buffer* buf, struct ub_packed_rrset_key* k,
        uint8_t* sig, uint8_t** can_owner, size_t* can_owner_len)
{
        int rrsig_labels = (int)sig[3];
        int fqdn_labels = dname_signame_label_count(k->rk.dname);
        *can_owner = sldns_buffer_current(buf);
        if(rrsig_labels == fqdn_labels) {
                /* no change */
                sldns_buffer_write(buf, k->rk.dname, k->rk.dname_len);
                query_dname_tolower(*can_owner);
                *can_owner_len = k->rk.dname_len;
                return;
        }
        log_assert(rrsig_labels < fqdn_labels);
        /* *. | fqdn(rightmost rrsig_labels) */
        if(rrsig_labels < fqdn_labels) {
                int i;
                uint8_t* nm = k->rk.dname;
                size_t len = k->rk.dname_len;
                /* so skip fqdn_labels-rrsig_labels */
                for(i=0; i<fqdn_labels-rrsig_labels; i++) {
                        dname_remove_label(&nm, &len);  
                }
                *can_owner_len = len+2;
                sldns_buffer_write(buf, (uint8_t*)"\001*", 2);
                sldns_buffer_write(buf, nm, len);
                query_dname_tolower(*can_owner);
        }
}

/**
 * Canonicalize Rdata in buffer.
 * @param buf: buffer at position just after the rdata.
 * @param rrset: rrset with type.
 * @param len: length of the rdata (including rdatalen uint16).
 */
static void
canonicalize_rdata(sldns_buffer* buf, struct ub_packed_rrset_key* rrset,
        size_t len)
{
        uint8_t* datstart = sldns_buffer_current(buf)-len+2;
        switch(ntohs(rrset->rk.type)) {
                case LDNS_RR_TYPE_NXT: 
                case LDNS_RR_TYPE_NS:
                case LDNS_RR_TYPE_MD:
                case LDNS_RR_TYPE_MF:
                case LDNS_RR_TYPE_CNAME:
                case LDNS_RR_TYPE_MB:
                case LDNS_RR_TYPE_MG:
                case LDNS_RR_TYPE_MR:
                case LDNS_RR_TYPE_PTR:
                case LDNS_RR_TYPE_DNAME:
                        /* type only has a single argument, the name */
                        query_dname_tolower(datstart);
                        return;
                case LDNS_RR_TYPE_MINFO:
                case LDNS_RR_TYPE_RP:
                case LDNS_RR_TYPE_SOA:
                        /* two names after another */
                        query_dname_tolower(datstart);
                        query_dname_tolower(datstart + 
                                dname_valid(datstart, len-2));
                        return;
                case LDNS_RR_TYPE_RT:
                case LDNS_RR_TYPE_AFSDB:
                case LDNS_RR_TYPE_KX:
                case LDNS_RR_TYPE_MX:
                        /* skip fixed part */
                        if(len < 2+2+1) /* rdlen, skiplen, 1byteroot */
                                return;
                        datstart += 2;
                        query_dname_tolower(datstart);
                        return;
                case LDNS_RR_TYPE_SIG:
                /* downcase the RRSIG, compat with BIND (kept it from SIG) */
                case LDNS_RR_TYPE_RRSIG:
                        /* skip fixed part */
                        if(len < 2+18+1)
                                return;
                        datstart += 18;
                        query_dname_tolower(datstart);
                        return;
                case LDNS_RR_TYPE_PX:
                        /* skip, then two names after another */
                        if(len < 2+2+1) 
                                return;
                        datstart += 2;
                        query_dname_tolower(datstart);
                        query_dname_tolower(datstart + 
                                dname_valid(datstart, len-2-2));
                        return;
                case LDNS_RR_TYPE_NAPTR:
                        if(len < 2+4)
                                return;
                        len -= 2+4;
                        datstart += 4;
                        if(len < (size_t)datstart[0]+1) /* skip text field */
                                return;
                        len -= (size_t)datstart[0]+1;
                        datstart += (size_t)datstart[0]+1;
                        if(len < (size_t)datstart[0]+1) /* skip text field */
                                return;
                        len -= (size_t)datstart[0]+1;
                        datstart += (size_t)datstart[0]+1;
                        if(len < (size_t)datstart[0]+1) /* skip text field */
                                return;
                        len -= (size_t)datstart[0]+1;
                        datstart += (size_t)datstart[0]+1;
                        if(len < 1)     /* check name is at least 1 byte*/
                                return;
                        query_dname_tolower(datstart);
                        return;
                case LDNS_RR_TYPE_SRV:
                        /* skip fixed part */
                        if(len < 2+6+1)
                                return;
                        datstart += 6;
                        query_dname_tolower(datstart);
                        return;

                /* do not canonicalize NSEC rdata name, compat with 
                 * from bind 9.4 signer, where it does not do so */
                case LDNS_RR_TYPE_NSEC: /* type starts with the name */
                case LDNS_RR_TYPE_HINFO: /* not downcased */
                /* A6 not supported */
                default:        
                        /* nothing to do for unknown types */
                        return;
        }
}

int rrset_canonical_equal(struct regional* region,
        struct ub_packed_rrset_key* k1, struct ub_packed_rrset_key* k2)
{
        struct rbtree_type sortree1, sortree2;
        struct canon_rr *rrs1, *rrs2, *p1, *p2;
        struct packed_rrset_data* d1=(struct packed_rrset_data*)k1->entry.data;
        struct packed_rrset_data* d2=(struct packed_rrset_data*)k2->entry.data;
        struct ub_packed_rrset_key fk;
        struct packed_rrset_data fd;
        size_t flen[2];
        uint8_t* fdata[2];

        /* basic compare */
        if(k1->rk.dname_len != k2->rk.dname_len ||
                k1->rk.flags != k2->rk.flags ||
                k1->rk.type != k2->rk.type ||
                k1->rk.rrset_class != k2->rk.rrset_class ||
                query_dname_compare(k1->rk.dname, k2->rk.dname) != 0)
                return 0;
        if(d1->ttl != d2->ttl ||
                d1->count != d2->count ||
                d1->rrsig_count != d2->rrsig_count ||
                d1->trust != d2->trust ||
                d1->security != d2->security)
                return 0;

        /* init */
        memset(&fk, 0, sizeof(fk));
        memset(&fd, 0, sizeof(fd));
        fk.entry.data = &fd;
        fd.count = 2;
        fd.rr_len = flen;
        fd.rr_data = fdata;
        rbtree_init(&sortree1, &canonical_tree_compare);
        rbtree_init(&sortree2, &canonical_tree_compare);
        if(d1->count > RR_COUNT_MAX || d2->count > RR_COUNT_MAX)
                return 1; /* protection against integer overflow */
        rrs1 = regional_alloc(region, sizeof(struct canon_rr)*d1->count);
        rrs2 = regional_alloc(region, sizeof(struct canon_rr)*d2->count);
        if(!rrs1 || !rrs2) return 1; /* alloc failure */

        /* sort */
        canonical_sort(k1, d1, &sortree1, rrs1);
        canonical_sort(k2, d2, &sortree2, rrs2);

        /* compare canonical-sorted RRs for canonical-equality */
        if(sortree1.count != sortree2.count)
                return 0;
        p1 = (struct canon_rr*)rbtree_first(&sortree1);
        p2 = (struct canon_rr*)rbtree_first(&sortree2);
        while(p1 != (struct canon_rr*)RBTREE_NULL &&
                p2 != (struct canon_rr*)RBTREE_NULL) {
                flen[0] = d1->rr_len[p1->rr_idx];
                flen[1] = d2->rr_len[p2->rr_idx];
                fdata[0] = d1->rr_data[p1->rr_idx];
                fdata[1] = d2->rr_data[p2->rr_idx];

                if(canonical_compare(&fk, 0, 1) != 0)
                        return 0;
                p1 = (struct canon_rr*)rbtree_next(&p1->node);
                p2 = (struct canon_rr*)rbtree_next(&p2->node);
        }
        return 1;
}

/**
 * Create canonical form of rrset in the scratch buffer.
 * @param region: temporary region.
 * @param buf: the buffer to use.
 * @param k: the rrset to insert.
 * @param sig: RRSIG rdata to include.
 * @param siglen: RRSIG rdata len excluding signature field, but inclusive
 *      signer name length.
 * @param sortree: if NULL is passed a new sorted rrset tree is built.
 *      Otherwise it is reused.
 * @param section: section of packet where this rrset comes from.
 * @param qstate: qstate with region.
 * @return false on alloc error.
 */
static int
rrset_canonical(struct regional* region, sldns_buffer* buf, 
        struct ub_packed_rrset_key* k, uint8_t* sig, size_t siglen,
        struct rbtree_type** sortree, sldns_pkt_section section,
        struct module_qstate* qstate)
{
        struct packed_rrset_data* d = (struct packed_rrset_data*)k->entry.data;
        uint8_t* can_owner = NULL;
        size_t can_owner_len = 0;
        struct canon_rr* walk;
        struct canon_rr* rrs;

        if(!*sortree) {
                *sortree = (struct rbtree_type*)regional_alloc(region, 
                        sizeof(rbtree_type));
                if(!*sortree)
                        return 0;
                if(d->count > RR_COUNT_MAX)
                        return 0; /* integer overflow protection */
                rrs = regional_alloc(region, sizeof(struct canon_rr)*d->count);
                if(!rrs) {
                        *sortree = NULL;
                        return 0;
                }
                rbtree_init(*sortree, &canonical_tree_compare);
                canonical_sort(k, d, *sortree, rrs);
        }

        sldns_buffer_clear(buf);
        sldns_buffer_write(buf, sig, siglen);
        /* canonicalize signer name */
        query_dname_tolower(sldns_buffer_begin(buf)+18); 
        RBTREE_FOR(walk, struct canon_rr*, (*sortree)) {
                /* see if there is enough space left in the buffer */
                if(sldns_buffer_remaining(buf) < can_owner_len + 2 + 2 + 4
                        + d->rr_len[walk->rr_idx]) {
                        log_err("verify: failed to canonicalize, "
                                "rrset too big");
                        return 0;
                }
                /* determine canonical owner name */
                if(can_owner)
                        sldns_buffer_write(buf, can_owner, can_owner_len);
                else    insert_can_owner(buf, k, sig, &can_owner, 
                                &can_owner_len);
                sldns_buffer_write(buf, &k->rk.type, 2);
                sldns_buffer_write(buf, &k->rk.rrset_class, 2);
                sldns_buffer_write(buf, sig+4, 4);
                sldns_buffer_write(buf, d->rr_data[walk->rr_idx], 
                        d->rr_len[walk->rr_idx]);
                canonicalize_rdata(buf, k, d->rr_len[walk->rr_idx]);
        }
        sldns_buffer_flip(buf);

        /* Replace RR owner with canonical owner for NSEC records in authority
         * section, to prevent that a wildcard synthesized NSEC can be used in
         * the non-existence proves. */
        if(ntohs(k->rk.type) == LDNS_RR_TYPE_NSEC &&
                section == LDNS_SECTION_AUTHORITY && qstate) {
                k->rk.dname = regional_alloc_init(qstate->region, can_owner,
                        can_owner_len);
                if(!k->rk.dname)
                        return 0;
                k->rk.dname_len = can_owner_len;
        }
        

        return 1;
}

int
rrset_canonicalize_to_buffer(struct regional* region, sldns_buffer* buf,
        struct ub_packed_rrset_key* k)
{
        struct rbtree_type* sortree = NULL;
        struct packed_rrset_data* d = (struct packed_rrset_data*)k->entry.data;
        uint8_t* can_owner = NULL;
        size_t can_owner_len = 0;
        struct canon_rr* walk;
        struct canon_rr* rrs;

        sortree = (struct rbtree_type*)regional_alloc(region,
                sizeof(rbtree_type));
        if(!sortree)
                return 0;
        if(d->count > RR_COUNT_MAX)
                return 0; /* integer overflow protection */
        rrs = regional_alloc(region, sizeof(struct canon_rr)*d->count);
        if(!rrs) {
                return 0;
        }
        rbtree_init(sortree, &canonical_tree_compare);
        canonical_sort(k, d, sortree, rrs);

        sldns_buffer_clear(buf);
        RBTREE_FOR(walk, struct canon_rr*, sortree) {
                /* see if there is enough space left in the buffer */
                if(sldns_buffer_remaining(buf) < can_owner_len + 2 + 2 + 4
                        + d->rr_len[walk->rr_idx]) {
                        log_err("verify: failed to canonicalize, "
                                "rrset too big");
                        return 0;
                }
                /* determine canonical owner name */
                if(can_owner)
                        sldns_buffer_write(buf, can_owner, can_owner_len);
                else    {
                        can_owner = sldns_buffer_current(buf);
                        sldns_buffer_write(buf, k->rk.dname, k->rk.dname_len);
                        query_dname_tolower(can_owner);
                        can_owner_len = k->rk.dname_len;
                }
                sldns_buffer_write(buf, &k->rk.type, 2);
                sldns_buffer_write(buf, &k->rk.rrset_class, 2);
                sldns_buffer_write_u32(buf, d->rr_ttl[walk->rr_idx]);
                sldns_buffer_write(buf, d->rr_data[walk->rr_idx],
                        d->rr_len[walk->rr_idx]);
                canonicalize_rdata(buf, k, d->rr_len[walk->rr_idx]);
        }
        sldns_buffer_flip(buf);
        return 1;
}

/** pretty print rrsig error with dates */
static void
sigdate_error(const char* str, int32_t expi, int32_t incep, int32_t now)
{
        struct tm tm;
        char expi_buf[16];
        char incep_buf[16];
        char now_buf[16];
        time_t te, ti, tn;

        if(verbosity < VERB_QUERY)
                return;
        te = (time_t)expi;
        ti = (time_t)incep;
        tn = (time_t)now;
        memset(&tm, 0, sizeof(tm));
        if(gmtime_r(&te, &tm) && strftime(expi_buf, 15, "%Y%m%d%H%M%S", &tm)
         &&gmtime_r(&ti, &tm) && strftime(incep_buf, 15, "%Y%m%d%H%M%S", &tm)
         &&gmtime_r(&tn, &tm) && strftime(now_buf, 15, "%Y%m%d%H%M%S", &tm)) {
                log_info("%s expi=%s incep=%s now=%s", str, expi_buf, 
                        incep_buf, now_buf);
        } else
                log_info("%s expi=%u incep=%u now=%u", str, (unsigned)expi, 
                        (unsigned)incep, (unsigned)now);
}

/** check rrsig dates */
static int
check_dates(struct val_env* ve, uint32_t unow, uint8_t* expi_p,
        uint8_t* incep_p, char** reason, sldns_ede_code *reason_bogus)
{
        /* read out the dates */
        uint32_t expi, incep, now;
        memmove(&expi, expi_p, sizeof(expi));
        memmove(&incep, incep_p, sizeof(incep));
        expi = ntohl(expi);
        incep = ntohl(incep);

        /* get current date */
        if(ve->date_override) {
                if(ve->date_override == -1) {
                        verbose(VERB_ALGO, "date override: ignore date"); 
                        return 1;
                }
                now = ve->date_override;
                verbose(VERB_ALGO, "date override option %d", (int)now); 
        } else  now = unow;

        /* check them */
        if(compare_1982(incep, expi) > 0) {
                sigdate_error("verify: inception after expiration, "
                        "signature bad", expi, incep, now);
                *reason = "signature inception after expiration";
                if(reason_bogus){
                        /* from RFC8914 on Signature Not Yet Valid: The resolver
                         * attempted to perform DNSSEC validation, but no
                         * signatures are presently valid and at least some are
                         * not yet valid. */
                        *reason_bogus = LDNS_EDE_SIGNATURE_NOT_YET_VALID;
                }

                return 0;
        }
        if(compare_1982(incep, now) > 0) {
                /* within skew ? (calc here to avoid calculation normally) */
                uint32_t skew = subtract_1982(incep, expi)/10;
                if(skew < (uint32_t)ve->skew_min) skew = ve->skew_min;
                if(skew > (uint32_t)ve->skew_max) skew = ve->skew_max;
                if(subtract_1982(now, incep) > skew) {
                        sigdate_error("verify: signature bad, current time is"
                                " before inception date", expi, incep, now);
                        *reason = "signature before inception date";
                        if(reason_bogus)
                                *reason_bogus = LDNS_EDE_SIGNATURE_NOT_YET_VALID;
                        return 0;
                }
                sigdate_error("verify warning suspicious signature inception "
                        " or bad local clock", expi, incep, now);
        }
        if(compare_1982(now, expi) > 0) {
                uint32_t skew = subtract_1982(incep, expi)/10;
                if(skew < (uint32_t)ve->skew_min) skew = ve->skew_min;
                if(skew > (uint32_t)ve->skew_max) skew = ve->skew_max;
                if(subtract_1982(expi, now) > skew) {
                        sigdate_error("verify: signature expired", expi, 
                                incep, now);
                        *reason = "signature expired";
                        if(reason_bogus)
                                *reason_bogus = LDNS_EDE_SIGNATURE_EXPIRED;
                        return 0;
                }
                sigdate_error("verify warning suspicious signature expiration "
                        " or bad local clock", expi, incep, now);
        }
        return 1;
}

/** adjust rrset TTL for verified rrset, compare to original TTL and expi */
static void
adjust_ttl(struct val_env* ve, uint32_t unow, 
        struct ub_packed_rrset_key* rrset, uint8_t* orig_p, 
        uint8_t* expi_p, uint8_t* incep_p)
{
        struct packed_rrset_data* d = 
                (struct packed_rrset_data*)rrset->entry.data;
        /* read out the dates */
        int32_t origttl, expittl, expi, incep, now;
        memmove(&origttl, orig_p, sizeof(origttl));
        memmove(&expi, expi_p, sizeof(expi));
        memmove(&incep, incep_p, sizeof(incep));
        expi = ntohl(expi);
        incep = ntohl(incep);
        origttl = ntohl(origttl);

        /* get current date */
        if(ve->date_override) {
                now = ve->date_override;
        } else  now = (int32_t)unow;
        expittl = (int32_t)((uint32_t)expi - (uint32_t)now);

        /* so now:
         * d->ttl: rrset ttl read from message or cache. May be reduced
         * origttl: original TTL from signature, authoritative TTL max.
         * MIN_TTL: minimum TTL from config.
         * expittl: TTL until the signature expires.
         *
         * Use the smallest of these, but don't let origttl set the TTL
         * below the minimum.
         */
        if(MIN_TTL > (time_t)origttl && d->ttl > MIN_TTL) {
                verbose(VERB_QUERY, "rrset TTL larger than original and minimum"
                        " TTL, adjusting TTL downwards to minimum ttl");
                d->ttl = MIN_TTL;
        }
        else if(MIN_TTL <= origttl && d->ttl > (time_t)origttl) {
                verbose(VERB_QUERY, "rrset TTL larger than original TTL, "
                "adjusting TTL downwards to original ttl");
                d->ttl = origttl;
        }

        if(expittl > 0 && d->ttl > (time_t)expittl) {
                verbose(VERB_ALGO, "rrset TTL larger than sig expiration ttl,"
                        " adjusting TTL downwards");
                d->ttl = expittl;
        }
}

enum sec_status 
dnskey_verify_rrset_sig(struct regional* region, sldns_buffer* buf, 
        struct val_env* ve, time_t now,
        struct ub_packed_rrset_key* rrset, struct ub_packed_rrset_key* dnskey,
        size_t dnskey_idx, size_t sig_idx,
        struct rbtree_type** sortree, int* buf_canon,
        char** reason, sldns_ede_code *reason_bogus,
        sldns_pkt_section section, struct module_qstate* qstate)
{
        enum sec_status sec;
        uint8_t* sig;           /* RRSIG rdata */
        size_t siglen;
        size_t rrnum = rrset_get_count(rrset);
        uint8_t* signer;        /* rrsig signer name */
        size_t signer_len;
        unsigned char* sigblock; /* signature rdata field */
        unsigned int sigblock_len;
        uint16_t ktag;          /* DNSKEY key tag */
        unsigned char* key;     /* public key rdata field */
        unsigned int keylen;
        rrset_get_rdata(rrset, rrnum + sig_idx, &sig, &siglen);
        /* min length of rdatalen, fixed rrsig, root signer, 1 byte sig */
        if(siglen < 2+20) {
                verbose(VERB_QUERY, "verify: signature too short");
                *reason = "signature too short";
                if(reason_bogus)
                        *reason_bogus = LDNS_EDE_DNSSEC_BOGUS;
                return sec_status_bogus;
        }

        if(!(dnskey_get_flags(dnskey, dnskey_idx) & DNSKEY_BIT_ZSK)) {
                verbose(VERB_QUERY, "verify: dnskey without ZSK flag");
                *reason = "dnskey without ZSK flag";
                if(reason_bogus)
                        *reason_bogus = LDNS_EDE_NO_ZONE_KEY_BIT_SET;
                return sec_status_bogus; 
        }

        if(dnskey_get_protocol(dnskey, dnskey_idx) != LDNS_DNSSEC_KEYPROTO) { 
                /* RFC 4034 says DNSKEY PROTOCOL MUST be 3 */
                verbose(VERB_QUERY, "verify: dnskey has wrong key protocol");
                *reason = "dnskey has wrong protocolnumber";
                if(reason_bogus)
                        *reason_bogus = LDNS_EDE_DNSSEC_BOGUS;
                return sec_status_bogus;
        }

        /* verify as many fields in rrsig as possible */
        signer = sig+2+18;
        signer_len = dname_valid(signer, siglen-2-18);
        if(!signer_len) {
                verbose(VERB_QUERY, "verify: malformed signer name");
                *reason = "signer name malformed";
                if(reason_bogus)
                        *reason_bogus = LDNS_EDE_DNSSEC_BOGUS;
                return sec_status_bogus; /* signer name invalid */
        }
        if(!dname_subdomain_c(rrset->rk.dname, signer)) {
                verbose(VERB_QUERY, "verify: signer name is off-tree");
                *reason = "signer name off-tree";
                if(reason_bogus)
                        *reason_bogus = LDNS_EDE_DNSSEC_BOGUS;
                return sec_status_bogus; /* signer name offtree */
        }
        sigblock = (unsigned char*)signer+signer_len;
        if(siglen < 2+18+signer_len+1) {
                verbose(VERB_QUERY, "verify: too short, no signature data");
                *reason = "signature too short, no signature data";
                if(reason_bogus)
                        *reason_bogus = LDNS_EDE_DNSSEC_BOGUS;
                return sec_status_bogus; /* sig rdf is < 1 byte */
        }
        sigblock_len = (unsigned int)(siglen - 2 - 18 - signer_len);

        /* verify key dname == sig signer name */
        if(query_dname_compare(signer, dnskey->rk.dname) != 0) {
                verbose(VERB_QUERY, "verify: wrong key for rrsig");
                log_nametypeclass(VERB_QUERY, "RRSIG signername is", 
                        signer, 0, 0);
                log_nametypeclass(VERB_QUERY, "the key name is", 
                        dnskey->rk.dname, 0, 0);
                *reason = "signer name mismatches key name";
                if(reason_bogus)
                        *reason_bogus = LDNS_EDE_DNSSEC_BOGUS;
                return sec_status_bogus;
        }

        /* verify covered type */
        /* memcmp works because type is in network format for rrset */
        if(memcmp(sig+2, &rrset->rk.type, 2) != 0) {
                verbose(VERB_QUERY, "verify: wrong type covered");
                *reason = "signature covers wrong type";
                if(reason_bogus)
                        *reason_bogus = LDNS_EDE_DNSSEC_BOGUS;
                return sec_status_bogus;
        }
        /* verify keytag and sig algo (possibly again) */
        if((int)sig[2+2] != dnskey_get_algo(dnskey, dnskey_idx)) {
                verbose(VERB_QUERY, "verify: wrong algorithm");
                *reason = "signature has wrong algorithm";
                if(reason_bogus)
                        *reason_bogus = LDNS_EDE_DNSSEC_BOGUS;
                return sec_status_bogus;
        }
        ktag = htons(dnskey_calc_keytag(dnskey, dnskey_idx));
        if(memcmp(sig+2+16, &ktag, 2) != 0) {
                verbose(VERB_QUERY, "verify: wrong keytag");
                *reason = "signature has wrong keytag";
                if(reason_bogus)
                        *reason_bogus = LDNS_EDE_DNSSEC_BOGUS;
                return sec_status_bogus;
        }

        /* verify labels is in a valid range */
        if((int)sig[2+3] > dname_signame_label_count(rrset->rk.dname)) {
                verbose(VERB_QUERY, "verify: labelcount out of range");
                *reason = "signature labelcount out of range";
                if(reason_bogus)
                        *reason_bogus = LDNS_EDE_DNSSEC_BOGUS;
                return sec_status_bogus;
        }

        /* original ttl, always ok */

        if(!*buf_canon) {
                /* create rrset canonical format in buffer, ready for 
                 * signature */
                if(!rrset_canonical(region, buf, rrset, sig+2, 
                        18 + signer_len, sortree, section, qstate)) {
                        log_err("verify: failed due to alloc error");
                        return sec_status_unchecked;
                }
                *buf_canon = 1;
        }

        /* check that dnskey is available */
        dnskey_get_pubkey(dnskey, dnskey_idx, &key, &keylen);
        if(!key) {
                verbose(VERB_QUERY, "verify: short DNSKEY RR");
                return sec_status_unchecked;
        }

        /* verify */
        sec = verify_canonrrset(buf, (int)sig[2+2],
                sigblock, sigblock_len, key, keylen, reason);

        /* count validation operation */
        if(qstate && qstate->env && qstate->env->mesh)
                qstate->env->mesh->val_ops++;
        
        if(sec == sec_status_secure) {
                /* check if TTL is too high - reduce if so */
                adjust_ttl(ve, now, rrset, sig+2+4, sig+2+8, sig+2+12);

                /* verify inception, expiration dates 
                 * Do this last so that if you ignore expired-sigs the
                 * rest is sure to be OK. */
                if(!check_dates(ve, now, sig+2+8, sig+2+12,
                        reason, reason_bogus)) {
                        return sec_status_bogus;
                }
        }

        return sec;
}