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monero/external/unbound/validator/val_utils.c
Erik de Castro Lopo a85b5759f3 Upgrade unbound library 
These files were pulled from the 1.6.3 release tarball.

This new version builds against OpenSSL version 1.1 which will be
the default in the new Debian Stable which is due to be released
RealSoonNow (tm).
2017-06-17 23:04:00 +10:00

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/*
* validator/val_utils.c - validator utility 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.
*/
#include "config.h"
#include "validator/val_utils.h"
#include "validator/validator.h"
#include "validator/val_kentry.h"
#include "validator/val_sigcrypt.h"
#include "validator/val_anchor.h"
#include "validator/val_nsec.h"
#include "validator/val_neg.h"
#include "services/cache/rrset.h"
#include "services/cache/dns.h"
#include "util/data/msgreply.h"
#include "util/data/packed_rrset.h"
#include "util/data/dname.h"
#include "util/net_help.h"
#include "util/module.h"
#include "util/regional.h"
#include "sldns/wire2str.h"
#include "sldns/parseutil.h"
enum val_classification
val_classify_response(uint16_t query_flags, struct query_info* origqinf,
struct query_info* qinf, struct reply_info* rep, size_t skip)
{
int rcode = (int)FLAGS_GET_RCODE(rep->flags);
size_t i;
/* Normal Name Error's are easy to detect -- but don't mistake a CNAME
* chain ending in NXDOMAIN. */
if(rcode == LDNS_RCODE_NXDOMAIN && rep->an_numrrsets == 0)
return VAL_CLASS_NAMEERROR;
/* check for referral: nonRD query and it looks like a nodata */
if(!(query_flags&BIT_RD) && rep->an_numrrsets == 0 &&
rcode == LDNS_RCODE_NOERROR) {
/* SOA record in auth indicates it is NODATA instead.
* All validation requiring NODATA messages have SOA in
* authority section. */
/* uses fact that answer section is empty */
int saw_ns = 0;
for(i=0; i<rep->ns_numrrsets; i++) {
if(ntohs(rep->rrsets[i]->rk.type) == LDNS_RR_TYPE_SOA)
return VAL_CLASS_NODATA;
if(ntohs(rep->rrsets[i]->rk.type) == LDNS_RR_TYPE_DS)
return VAL_CLASS_REFERRAL;
if(ntohs(rep->rrsets[i]->rk.type) == LDNS_RR_TYPE_NS)
saw_ns = 1;
}
return saw_ns?VAL_CLASS_REFERRAL:VAL_CLASS_NODATA;
}
/* root referral where NS set is in the answer section */
if(!(query_flags&BIT_RD) && rep->ns_numrrsets == 0 &&
rep->an_numrrsets == 1 && rcode == LDNS_RCODE_NOERROR &&
ntohs(rep->rrsets[0]->rk.type) == LDNS_RR_TYPE_NS &&
query_dname_compare(rep->rrsets[0]->rk.dname,
origqinf->qname) != 0)
return VAL_CLASS_REFERRAL;
/* dump bad messages */
if(rcode != LDNS_RCODE_NOERROR && rcode != LDNS_RCODE_NXDOMAIN)
return VAL_CLASS_UNKNOWN;
/* next check if the skip into the answer section shows no answer */
if(skip>0 && rep->an_numrrsets <= skip)
return VAL_CLASS_CNAMENOANSWER;
/* Next is NODATA */
if(rcode == LDNS_RCODE_NOERROR && rep->an_numrrsets == 0)
return VAL_CLASS_NODATA;
/* We distinguish between CNAME response and other positive/negative
* responses because CNAME answers require extra processing. */
/* We distinguish between ANY and CNAME or POSITIVE because
* ANY responses are validated differently. */
if(rcode == LDNS_RCODE_NOERROR && qinf->qtype == LDNS_RR_TYPE_ANY)
return VAL_CLASS_ANY;
/* Note that DNAMEs will be ignored here, unless qtype=DNAME. Unless
* qtype=CNAME, this will yield a CNAME response. */
for(i=skip; i<rep->an_numrrsets; i++) {
if(rcode == LDNS_RCODE_NOERROR &&
ntohs(rep->rrsets[i]->rk.type) == qinf->qtype)
return VAL_CLASS_POSITIVE;
if(ntohs(rep->rrsets[i]->rk.type) == LDNS_RR_TYPE_CNAME)
return VAL_CLASS_CNAME;
}
log_dns_msg("validator: error. failed to classify response message: ",
qinf, rep);
return VAL_CLASS_UNKNOWN;
}
/** Get signer name from RRSIG */
static void
rrsig_get_signer(uint8_t* data, size_t len, uint8_t** sname, size_t* slen)
{
/* RRSIG rdata is not allowed to be compressed, it is stored
* uncompressed in memory as well, so return a ptr to the name */
if(len < 21) {
/* too short RRSig:
* short, byte, byte, long, long, long, short, "." is
* 2 1 1 4 4 4 2 1 = 19
* and a skip of 18 bytes to the name.
* +2 for the rdatalen is 21 bytes len for root label */
*sname = NULL;
*slen = 0;
return;
}
data += 20; /* skip the fixed size bits */
len -= 20;
*slen = dname_valid(data, len);
if(!*slen) {
/* bad dname in this rrsig. */
*sname = NULL;
return;
}
*sname = data;
}
void
val_find_rrset_signer(struct ub_packed_rrset_key* rrset, uint8_t** sname,
size_t* slen)
{
struct packed_rrset_data* d = (struct packed_rrset_data*)
rrset->entry.data;
/* return signer for first signature, or NULL */
if(d->rrsig_count == 0) {
*sname = NULL;
*slen = 0;
return;
}
/* get rrsig signer name out of the signature */
rrsig_get_signer(d->rr_data[d->count], d->rr_len[d->count],
sname, slen);
}
/**
* Find best signer name in this set of rrsigs.
* @param rrset: which rrsigs to look through.
* @param qinf: the query name that needs validation.
* @param signer_name: the best signer_name. Updated if a better one is found.
* @param signer_len: length of signer name.
* @param matchcount: count of current best name (starts at 0 for no match).
* Updated if match is improved.
*/
static void
val_find_best_signer(struct ub_packed_rrset_key* rrset,
struct query_info* qinf, uint8_t** signer_name, size_t* signer_len,
int* matchcount)
{
struct packed_rrset_data* d = (struct packed_rrset_data*)
rrset->entry.data;
uint8_t* sign;
size_t i;
int m;
for(i=d->count; i<d->count+d->rrsig_count; i++) {
sign = d->rr_data[i]+2+18;
/* look at signatures that are valid (long enough),
* and have a signer name that is a superdomain of qname,
* and then check the number of labels in the shared topdomain
* improve the match if possible */
if(d->rr_len[i] > 2+19 && /* rdata, sig + root label*/
dname_subdomain_c(qinf->qname, sign)) {
(void)dname_lab_cmp(qinf->qname,
dname_count_labels(qinf->qname),
sign, dname_count_labels(sign), &m);
if(m > *matchcount) {
*matchcount = m;
*signer_name = sign;
(void)dname_count_size_labels(*signer_name,
signer_len);
}
}
}
}
void
val_find_signer(enum val_classification subtype, struct query_info* qinf,
struct reply_info* rep, size_t skip, uint8_t** signer_name,
size_t* signer_len)
{
size_t i;
if(subtype == VAL_CLASS_POSITIVE) {
/* check for the answer rrset */
for(i=skip; i<rep->an_numrrsets; i++) {
if(query_dname_compare(qinf->qname,
rep->rrsets[i]->rk.dname) == 0) {
val_find_rrset_signer(rep->rrsets[i],
signer_name, signer_len);
return;
}
}
*signer_name = NULL;
*signer_len = 0;
} else if(subtype == VAL_CLASS_CNAME) {
/* check for the first signed cname/dname rrset */
for(i=skip; i<rep->an_numrrsets; i++) {
val_find_rrset_signer(rep->rrsets[i],
signer_name, signer_len);
if(*signer_name)
return;
if(ntohs(rep->rrsets[i]->rk.type) != LDNS_RR_TYPE_DNAME)
break; /* only check CNAME after a DNAME */
}
*signer_name = NULL;
*signer_len = 0;
} else if(subtype == VAL_CLASS_NAMEERROR
|| subtype == VAL_CLASS_NODATA) {
/*Check to see if the AUTH section NSEC record(s) have rrsigs*/
for(i=rep->an_numrrsets; i<
rep->an_numrrsets+rep->ns_numrrsets; i++) {
if(ntohs(rep->rrsets[i]->rk.type) == LDNS_RR_TYPE_NSEC
|| ntohs(rep->rrsets[i]->rk.type) ==
LDNS_RR_TYPE_NSEC3) {
val_find_rrset_signer(rep->rrsets[i],
signer_name, signer_len);
return;
}
}
} else if(subtype == VAL_CLASS_CNAMENOANSWER) {
/* find closest superdomain signer name in authority section
* NSEC and NSEC3s */
int matchcount = 0;
*signer_name = NULL;
*signer_len = 0;
for(i=rep->an_numrrsets; i<rep->an_numrrsets+rep->
ns_numrrsets; i++) {
if(ntohs(rep->rrsets[i]->rk.type) == LDNS_RR_TYPE_NSEC
|| ntohs(rep->rrsets[i]->rk.type) ==
LDNS_RR_TYPE_NSEC3) {
val_find_best_signer(rep->rrsets[i], qinf,
signer_name, signer_len, &matchcount);
}
}
} else if(subtype == VAL_CLASS_ANY) {
/* check for one of the answer rrset that has signatures,
* or potentially a DNAME is in use with a different qname */
for(i=skip; i<rep->an_numrrsets; i++) {
if(query_dname_compare(qinf->qname,
rep->rrsets[i]->rk.dname) == 0) {
val_find_rrset_signer(rep->rrsets[i],
signer_name, signer_len);
if(*signer_name)
return;
}
}
/* no answer RRSIGs with qname, try a DNAME */
if(skip < rep->an_numrrsets &&
ntohs(rep->rrsets[skip]->rk.type) ==
LDNS_RR_TYPE_DNAME) {
val_find_rrset_signer(rep->rrsets[skip],
signer_name, signer_len);
if(*signer_name)
return;
}
*signer_name = NULL;
*signer_len = 0;
} else if(subtype == VAL_CLASS_REFERRAL) {
/* find keys for the item at skip */
if(skip < rep->rrset_count) {
val_find_rrset_signer(rep->rrsets[skip],
signer_name, signer_len);
return;
}
*signer_name = NULL;
*signer_len = 0;
} else {
verbose(VERB_QUERY, "find_signer: could not find signer name"
" for unknown type response");
*signer_name = NULL;
*signer_len = 0;
}
}
/** 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;
}
/** return TTL of rrset */
static uint32_t
rrset_get_ttl(struct ub_packed_rrset_key* rrset)
{
struct packed_rrset_data* d = (struct packed_rrset_data*)
rrset->entry.data;
if(!d) return 0;
return d->ttl;
}
enum sec_status
val_verify_rrset(struct module_env* env, struct val_env* ve,
struct ub_packed_rrset_key* rrset, struct ub_packed_rrset_key* keys,
uint8_t* sigalg, char** reason)
{
enum sec_status sec;
struct packed_rrset_data* d = (struct packed_rrset_data*)rrset->
entry.data;
if(d->security == sec_status_secure) {
/* re-verify all other statuses, because keyset may change*/
log_nametypeclass(VERB_ALGO, "verify rrset cached",
rrset->rk.dname, ntohs(rrset->rk.type),
ntohs(rrset->rk.rrset_class));
return d->security;
}
/* check in the cache if verification has already been done */
rrset_check_sec_status(env->rrset_cache, rrset, *env->now);
if(d->security == sec_status_secure) {
log_nametypeclass(VERB_ALGO, "verify rrset from cache",
rrset->rk.dname, ntohs(rrset->rk.type),
ntohs(rrset->rk.rrset_class));
return d->security;
}
log_nametypeclass(VERB_ALGO, "verify rrset", rrset->rk.dname,
ntohs(rrset->rk.type), ntohs(rrset->rk.rrset_class));
sec = dnskeyset_verify_rrset(env, ve, rrset, keys, sigalg, reason);
verbose(VERB_ALGO, "verify result: %s", sec_status_to_string(sec));
regional_free_all(env->scratch);
/* update rrset security status
* only improves security status
* and bogus is set only once, even if we rechecked the status */
if(sec > d->security) {
d->security = sec;
if(sec == sec_status_secure)
d->trust = rrset_trust_validated;
else if(sec == sec_status_bogus) {
size_t i;
/* update ttl for rrset to fixed value. */
d->ttl = ve->bogus_ttl;
for(i=0; i<d->count+d->rrsig_count; i++)
d->rr_ttl[i] = ve->bogus_ttl;
/* leave RR specific TTL: not used for determine
* if RRset timed out and clients see proper value. */
lock_basic_lock(&ve->bogus_lock);
ve->num_rrset_bogus++;
lock_basic_unlock(&ve->bogus_lock);
}
/* if status updated - store in cache for reuse */
rrset_update_sec_status(env->rrset_cache, rrset, *env->now);
}
return sec;
}
enum sec_status
val_verify_rrset_entry(struct module_env* env, struct val_env* ve,
struct ub_packed_rrset_key* rrset, struct key_entry_key* kkey,
char** reason)
{
/* temporary dnskey rrset-key */
struct ub_packed_rrset_key dnskey;
struct key_entry_data* kd = (struct key_entry_data*)kkey->entry.data;
enum sec_status sec;
dnskey.rk.type = htons(kd->rrset_type);
dnskey.rk.rrset_class = htons(kkey->key_class);
dnskey.rk.flags = 0;
dnskey.rk.dname = kkey->name;
dnskey.rk.dname_len = kkey->namelen;
dnskey.entry.key = &dnskey;
dnskey.entry.data = kd->rrset_data;
sec = val_verify_rrset(env, ve, rrset, &dnskey, kd->algo, reason);
return sec;
}
/** verify that a DS RR hashes to a key and that key signs the set */
static enum sec_status
verify_dnskeys_with_ds_rr(struct module_env* env, struct val_env* ve,
struct ub_packed_rrset_key* dnskey_rrset,
struct ub_packed_rrset_key* ds_rrset, size_t ds_idx, char** reason)
{
enum sec_status sec = sec_status_bogus;
size_t i, num, numchecked = 0, numhashok = 0;
num = rrset_get_count(dnskey_rrset);
for(i=0; i<num; i++) {
/* Skip DNSKEYs that don't match the basic criteria. */
if(ds_get_key_algo(ds_rrset, ds_idx)
!= dnskey_get_algo(dnskey_rrset, i)
|| dnskey_calc_keytag(dnskey_rrset, i)
!= ds_get_keytag(ds_rrset, ds_idx)) {
continue;
}
numchecked++;
verbose(VERB_ALGO, "attempt DS match algo %d keytag %d",
ds_get_key_algo(ds_rrset, ds_idx),
ds_get_keytag(ds_rrset, ds_idx));
/* Convert the candidate DNSKEY into a hash using the
* same DS hash algorithm. */
if(!ds_digest_match_dnskey(env, dnskey_rrset, i, ds_rrset,
ds_idx)) {
verbose(VERB_ALGO, "DS match attempt failed");
continue;
}
numhashok++;
verbose(VERB_ALGO, "DS match digest ok, trying signature");
/* Otherwise, we have a match! Make sure that the DNSKEY
* verifies *with this key* */
sec = dnskey_verify_rrset(env, ve, dnskey_rrset,
dnskey_rrset, i, reason);
if(sec == sec_status_secure) {
return sec;
}
/* If it didn't validate with the DNSKEY, try the next one! */
}
if(numchecked == 0)
algo_needs_reason(env, ds_get_key_algo(ds_rrset, ds_idx),
reason, "no keys have a DS");
else if(numhashok == 0)
*reason = "DS hash mismatches key";
else if(!*reason)
*reason = "keyset not secured by DNSKEY that matches DS";
return sec_status_bogus;
}
int val_favorite_ds_algo(struct ub_packed_rrset_key* ds_rrset)
{
size_t i, num = rrset_get_count(ds_rrset);
int d, digest_algo = 0; /* DS digest algo 0 is not used. */
/* find favorite algo, for now, highest number supported */
for(i=0; i<num; i++) {
if(!ds_digest_algo_is_supported(ds_rrset, i) ||
!ds_key_algo_is_supported(ds_rrset, i)) {
continue;
}
d = ds_get_digest_algo(ds_rrset, i);
if(d > digest_algo)
digest_algo = d;
}
return digest_algo;
}
enum sec_status
val_verify_DNSKEY_with_DS(struct module_env* env, struct val_env* ve,
struct ub_packed_rrset_key* dnskey_rrset,
struct ub_packed_rrset_key* ds_rrset, uint8_t* sigalg, char** reason)
{
/* as long as this is false, we can consider this DS rrset to be
* equivalent to no DS rrset. */
int has_useful_ds = 0, digest_algo, alg;
struct algo_needs needs;
size_t i, num;
enum sec_status sec;
if(dnskey_rrset->rk.dname_len != ds_rrset->rk.dname_len ||
query_dname_compare(dnskey_rrset->rk.dname, ds_rrset->rk.dname)
!= 0) {
verbose(VERB_QUERY, "DNSKEY RRset did not match DS RRset "
"by name");
*reason = "DNSKEY RRset did not match DS RRset by name";
return sec_status_bogus;
}
if(sigalg) {
/* harden against algo downgrade is enabled */
digest_algo = val_favorite_ds_algo(ds_rrset);
algo_needs_init_ds(&needs, ds_rrset, digest_algo, sigalg);
} else {
/* accept any key algo, any digest algo */
digest_algo = -1;
}
num = rrset_get_count(ds_rrset);
for(i=0; i<num; i++) {
/* Check to see if we can understand this DS.
* And check it is the strongest digest */
if(!ds_digest_algo_is_supported(ds_rrset, i) ||
!ds_key_algo_is_supported(ds_rrset, i) ||
(sigalg && (ds_get_digest_algo(ds_rrset, i) != digest_algo))) {
continue;
}
/* Once we see a single DS with a known digestID and
* algorithm, we cannot return INSECURE (with a
* "null" KeyEntry). */
has_useful_ds = 1;
sec = verify_dnskeys_with_ds_rr(env, ve, dnskey_rrset,
ds_rrset, i, reason);
if(sec == sec_status_secure) {
if(!sigalg || algo_needs_set_secure(&needs,
(uint8_t)ds_get_key_algo(ds_rrset, i))) {
verbose(VERB_ALGO, "DS matched DNSKEY.");
return sec_status_secure;
}
} else if(sigalg && sec == sec_status_bogus) {
algo_needs_set_bogus(&needs,
(uint8_t)ds_get_key_algo(ds_rrset, i));
}
}
/* None of the DS's worked out. */
/* If no DSs were understandable, then this is OK. */
if(!has_useful_ds) {
verbose(VERB_ALGO, "No usable DS records were found -- "
"treating as insecure.");
return sec_status_insecure;
}
/* If any were understandable, then it is bad. */
verbose(VERB_QUERY, "Failed to match any usable DS to a DNSKEY.");
if(sigalg && (alg=algo_needs_missing(&needs)) != 0) {
algo_needs_reason(env, alg, reason, "missing verification of "
"DNSKEY signature");
}
return sec_status_bogus;
}
struct key_entry_key*
val_verify_new_DNSKEYs(struct regional* region, struct module_env* env,
struct val_env* ve, struct ub_packed_rrset_key* dnskey_rrset,
struct ub_packed_rrset_key* ds_rrset, int downprot, char** reason)
{
uint8_t sigalg[ALGO_NEEDS_MAX+1];
enum sec_status sec = val_verify_DNSKEY_with_DS(env, ve,
dnskey_rrset, ds_rrset, downprot?sigalg:NULL, reason);
if(sec == sec_status_secure) {
return key_entry_create_rrset(region,
ds_rrset->rk.dname, ds_rrset->rk.dname_len,
ntohs(ds_rrset->rk.rrset_class), dnskey_rrset,
downprot?sigalg:NULL, *env->now);
} else if(sec == sec_status_insecure) {
return key_entry_create_null(region, ds_rrset->rk.dname,
ds_rrset->rk.dname_len,
ntohs(ds_rrset->rk.rrset_class),
rrset_get_ttl(ds_rrset), *env->now);
}
return key_entry_create_bad(region, ds_rrset->rk.dname,
ds_rrset->rk.dname_len, ntohs(ds_rrset->rk.rrset_class),
BOGUS_KEY_TTL, *env->now);
}
enum sec_status
val_verify_DNSKEY_with_TA(struct module_env* env, struct val_env* ve,
struct ub_packed_rrset_key* dnskey_rrset,
struct ub_packed_rrset_key* ta_ds,
struct ub_packed_rrset_key* ta_dnskey, uint8_t* sigalg, char** reason)
{
/* as long as this is false, we can consider this anchor to be
* equivalent to no anchor. */
int has_useful_ta = 0, digest_algo = 0, alg;
struct algo_needs needs;
size_t i, num;
enum sec_status sec;
if(ta_ds && (dnskey_rrset->rk.dname_len != ta_ds->rk.dname_len ||
query_dname_compare(dnskey_rrset->rk.dname, ta_ds->rk.dname)
!= 0)) {
verbose(VERB_QUERY, "DNSKEY RRset did not match DS RRset "
"by name");
*reason = "DNSKEY RRset did not match DS RRset by name";
return sec_status_bogus;
}
if(ta_dnskey && (dnskey_rrset->rk.dname_len != ta_dnskey->rk.dname_len
|| query_dname_compare(dnskey_rrset->rk.dname, ta_dnskey->rk.dname)
!= 0)) {
verbose(VERB_QUERY, "DNSKEY RRset did not match anchor RRset "
"by name");
*reason = "DNSKEY RRset did not match anchor RRset by name";
return sec_status_bogus;
}
if(ta_ds)
digest_algo = val_favorite_ds_algo(ta_ds);
if(sigalg) {
if(ta_ds)
algo_needs_init_ds(&needs, ta_ds, digest_algo, sigalg);
else memset(&needs, 0, sizeof(needs));
if(ta_dnskey)
algo_needs_init_dnskey_add(&needs, ta_dnskey, sigalg);
}
if(ta_ds) {
num = rrset_get_count(ta_ds);
for(i=0; i<num; i++) {
/* Check to see if we can understand this DS.
* And check it is the strongest digest */
if(!ds_digest_algo_is_supported(ta_ds, i) ||
!ds_key_algo_is_supported(ta_ds, i) ||
ds_get_digest_algo(ta_ds, i) != digest_algo)
continue;
/* Once we see a single DS with a known digestID and
* algorithm, we cannot return INSECURE (with a
* "null" KeyEntry). */
has_useful_ta = 1;
sec = verify_dnskeys_with_ds_rr(env, ve, dnskey_rrset,
ta_ds, i, reason);
if(sec == sec_status_secure) {
if(!sigalg || algo_needs_set_secure(&needs,
(uint8_t)ds_get_key_algo(ta_ds, i))) {
verbose(VERB_ALGO, "DS matched DNSKEY.");
return sec_status_secure;
}
} else if(sigalg && sec == sec_status_bogus) {
algo_needs_set_bogus(&needs,
(uint8_t)ds_get_key_algo(ta_ds, i));
}
}
}
/* None of the DS's worked out: check the DNSKEYs. */
if(ta_dnskey) {
num = rrset_get_count(ta_dnskey);
for(i=0; i<num; i++) {
/* Check to see if we can understand this DNSKEY */
if(!dnskey_algo_is_supported(ta_dnskey, i))
continue;
/* we saw a useful TA */
has_useful_ta = 1;
sec = dnskey_verify_rrset(env, ve, dnskey_rrset,
ta_dnskey, i, reason);
if(sec == sec_status_secure) {
if(!sigalg || algo_needs_set_secure(&needs,
(uint8_t)dnskey_get_algo(ta_dnskey, i))) {
verbose(VERB_ALGO, "anchor matched DNSKEY.");
return sec_status_secure;
}
} else if(sigalg && sec == sec_status_bogus) {
algo_needs_set_bogus(&needs,
(uint8_t)dnskey_get_algo(ta_dnskey, i));
}
}
}
/* If no DSs were understandable, then this is OK. */
if(!has_useful_ta) {
verbose(VERB_ALGO, "No usable trust anchors were found -- "
"treating as insecure.");
return sec_status_insecure;
}
/* If any were understandable, then it is bad. */
verbose(VERB_QUERY, "Failed to match any usable anchor to a DNSKEY.");
if(sigalg && (alg=algo_needs_missing(&needs)) != 0) {
algo_needs_reason(env, alg, reason, "missing verification of "
"DNSKEY signature");
}
return sec_status_bogus;
}
struct key_entry_key*
val_verify_new_DNSKEYs_with_ta(struct regional* region, struct module_env* env,
struct val_env* ve, struct ub_packed_rrset_key* dnskey_rrset,
struct ub_packed_rrset_key* ta_ds_rrset,
struct ub_packed_rrset_key* ta_dnskey_rrset, int downprot,
char** reason)
{
uint8_t sigalg[ALGO_NEEDS_MAX+1];
enum sec_status sec = val_verify_DNSKEY_with_TA(env, ve,
dnskey_rrset, ta_ds_rrset, ta_dnskey_rrset,
downprot?sigalg:NULL, reason);
if(sec == sec_status_secure) {
return key_entry_create_rrset(region,
dnskey_rrset->rk.dname, dnskey_rrset->rk.dname_len,
ntohs(dnskey_rrset->rk.rrset_class), dnskey_rrset,
downprot?sigalg:NULL, *env->now);
} else if(sec == sec_status_insecure) {
return key_entry_create_null(region, dnskey_rrset->rk.dname,
dnskey_rrset->rk.dname_len,
ntohs(dnskey_rrset->rk.rrset_class),
rrset_get_ttl(dnskey_rrset), *env->now);
}
return key_entry_create_bad(region, dnskey_rrset->rk.dname,
dnskey_rrset->rk.dname_len, ntohs(dnskey_rrset->rk.rrset_class),
BOGUS_KEY_TTL, *env->now);
}
int
val_dsset_isusable(struct ub_packed_rrset_key* ds_rrset)
{
size_t i;
for(i=0; i<rrset_get_count(ds_rrset); i++) {
if(ds_digest_algo_is_supported(ds_rrset, i) &&
ds_key_algo_is_supported(ds_rrset, i))
return 1;
}
if(verbosity < VERB_ALGO)
return 0;
if(rrset_get_count(ds_rrset) == 0)
verbose(VERB_ALGO, "DS is not usable");
else {
/* report usability for the first DS RR */
sldns_lookup_table *lt;
char herr[64], aerr[64];
lt = sldns_lookup_by_id(sldns_hashes,
(int)ds_get_digest_algo(ds_rrset, i));
if(lt) snprintf(herr, sizeof(herr), "%s", lt->name);
else snprintf(herr, sizeof(herr), "%d",
(int)ds_get_digest_algo(ds_rrset, i));
lt = sldns_lookup_by_id(sldns_algorithms,
(int)ds_get_key_algo(ds_rrset, i));
if(lt) snprintf(aerr, sizeof(aerr), "%s", lt->name);
else snprintf(aerr, sizeof(aerr), "%d",
(int)ds_get_key_algo(ds_rrset, i));
verbose(VERB_ALGO, "DS unsupported, hash %s %s, "
"key algorithm %s %s", herr,
(ds_digest_algo_is_supported(ds_rrset, 0)?
"(supported)":"(unsupported)"), aerr,
(ds_key_algo_is_supported(ds_rrset, 0)?
"(supported)":"(unsupported)"));
}
return 0;
}
/** get label count for a signature */
static uint8_t
rrsig_get_labcount(struct packed_rrset_data* d, size_t sig)
{
if(d->rr_len[sig] < 2+4)
return 0; /* bad sig length */
return d->rr_data[sig][2+3];
}
int
val_rrset_wildcard(struct ub_packed_rrset_key* rrset, uint8_t** wc)
{
struct packed_rrset_data* d = (struct packed_rrset_data*)rrset->
entry.data;
uint8_t labcount;
int labdiff;
uint8_t* wn;
size_t i, wl;
if(d->rrsig_count == 0) {
return 1;
}
labcount = rrsig_get_labcount(d, d->count + 0);
/* check rest of signatures identical */
for(i=1; i<d->rrsig_count; i++) {
if(labcount != rrsig_get_labcount(d, d->count + i)) {
return 0;
}
}
/* OK the rrsigs check out */
/* if the RRSIG label count is shorter than the number of actual
* labels, then this rrset was synthesized from a wildcard.
* Note that the RRSIG label count doesn't count the root label. */
wn = rrset->rk.dname;
wl = rrset->rk.dname_len;
/* skip a leading wildcard label in the dname (RFC4035 2.2) */
if(dname_is_wild(wn)) {
wn += 2;
wl -= 2;
}
labdiff = (dname_count_labels(wn) - 1) - (int)labcount;
if(labdiff > 0) {
*wc = wn;
dname_remove_labels(wc, &wl, labdiff);
return 1;
}
return 1;
}
int
val_chase_cname(struct query_info* qchase, struct reply_info* rep,
size_t* cname_skip) {
size_t i;
/* skip any DNAMEs, go to the CNAME for next part */
for(i = *cname_skip; i < rep->an_numrrsets; i++) {
if(ntohs(rep->rrsets[i]->rk.type) == LDNS_RR_TYPE_CNAME &&
query_dname_compare(qchase->qname, rep->rrsets[i]->
rk.dname) == 0) {
qchase->qname = NULL;
get_cname_target(rep->rrsets[i], &qchase->qname,
&qchase->qname_len);
if(!qchase->qname)
return 0; /* bad CNAME rdata */
(*cname_skip) = i+1;
return 1;
}
}
return 0; /* CNAME classified but no matching CNAME ?! */
}
/** see if rrset has signer name as one of the rrsig signers */
static int
rrset_has_signer(struct ub_packed_rrset_key* rrset, uint8_t* name, size_t len)
{
struct packed_rrset_data* d = (struct packed_rrset_data*)rrset->
entry.data;
size_t i;
for(i = d->count; i< d->count+d->rrsig_count; i++) {
if(d->rr_len[i] > 2+18+len) {
/* at least rdatalen + signature + signame (+1 sig)*/
if(!dname_valid(d->rr_data[i]+2+18, d->rr_len[i]-2-18))
continue;
if(query_dname_compare(name, d->rr_data[i]+2+18) == 0)
{
return 1;
}
}
}
return 0;
}
void
val_fill_reply(struct reply_info* chase, struct reply_info* orig,
size_t skip, uint8_t* name, size_t len, uint8_t* signer)
{
size_t i;
int seen_dname = 0;
chase->rrset_count = 0;
chase->an_numrrsets = 0;
chase->ns_numrrsets = 0;
chase->ar_numrrsets = 0;
/* ANSWER section */
for(i=skip; i<orig->an_numrrsets; i++) {
if(!signer) {
if(query_dname_compare(name,
orig->rrsets[i]->rk.dname) == 0)
chase->rrsets[chase->an_numrrsets++] =
orig->rrsets[i];
} else if(seen_dname && ntohs(orig->rrsets[i]->rk.type) ==
LDNS_RR_TYPE_CNAME) {
chase->rrsets[chase->an_numrrsets++] = orig->rrsets[i];
seen_dname = 0;
} else if(rrset_has_signer(orig->rrsets[i], name, len)) {
chase->rrsets[chase->an_numrrsets++] = orig->rrsets[i];
if(ntohs(orig->rrsets[i]->rk.type) ==
LDNS_RR_TYPE_DNAME) {
seen_dname = 1;
}
}
}
/* AUTHORITY section */
for(i = (skip > orig->an_numrrsets)?skip:orig->an_numrrsets;
i<orig->an_numrrsets+orig->ns_numrrsets;
i++) {
if(!signer) {
if(query_dname_compare(name,
orig->rrsets[i]->rk.dname) == 0)
chase->rrsets[chase->an_numrrsets+
chase->ns_numrrsets++] = orig->rrsets[i];
} else if(rrset_has_signer(orig->rrsets[i], name, len)) {
chase->rrsets[chase->an_numrrsets+
chase->ns_numrrsets++] = orig->rrsets[i];
}
}
/* ADDITIONAL section */
for(i= (skip>orig->an_numrrsets+orig->ns_numrrsets)?
skip:orig->an_numrrsets+orig->ns_numrrsets;
i<orig->rrset_count; i++) {
if(!signer) {
if(query_dname_compare(name,
orig->rrsets[i]->rk.dname) == 0)
chase->rrsets[chase->an_numrrsets
+orig->ns_numrrsets+chase->ar_numrrsets++]
= orig->rrsets[i];
} else if(rrset_has_signer(orig->rrsets[i], name, len)) {
chase->rrsets[chase->an_numrrsets+orig->ns_numrrsets+
chase->ar_numrrsets++] = orig->rrsets[i];
}
}
chase->rrset_count = chase->an_numrrsets + chase->ns_numrrsets +
chase->ar_numrrsets;
}
void val_reply_remove_auth(struct reply_info* rep, size_t index)
{
log_assert(index < rep->rrset_count);
log_assert(index >= rep->an_numrrsets);
log_assert(index < rep->an_numrrsets+rep->ns_numrrsets);
memmove(rep->rrsets+index, rep->rrsets+index+1,
sizeof(struct ub_packed_rrset_key*)*
(rep->rrset_count - index - 1));
rep->ns_numrrsets--;
rep->rrset_count--;
}
void
val_check_nonsecure(struct val_env* ve, struct reply_info* rep)
{
size_t i;
/* authority */
for(i=rep->an_numrrsets; i<rep->an_numrrsets+rep->ns_numrrsets; i++) {
if(((struct packed_rrset_data*)rep->rrsets[i]->entry.data)
->security != sec_status_secure) {
/* because we want to return the authentic original
* message when presented with CD-flagged queries,
* we need to preserve AUTHORITY section data.
* However, this rrset is not signed or signed
* with the wrong keys. Validation has tried to
* verify this rrset with the keysets of import.
* But this rrset did not verify.
* Therefore the message is bogus.
*/
/* check if authority consists of only an NS record
* which is bad, and there is an answer section with
* data. In that case, delete NS and additional to
* be lenient and make a minimal response */
if(rep->an_numrrsets != 0 && rep->ns_numrrsets == 1 &&
ntohs(rep->rrsets[i]->rk.type)
== LDNS_RR_TYPE_NS) {
verbose(VERB_ALGO, "truncate to minimal");
rep->ns_numrrsets = 0;
rep->ar_numrrsets = 0;
rep->rrset_count = rep->an_numrrsets;
return;
}
log_nametypeclass(VERB_QUERY, "message is bogus, "
"non secure rrset",
rep->rrsets[i]->rk.dname,
ntohs(rep->rrsets[i]->rk.type),
ntohs(rep->rrsets[i]->rk.rrset_class));
rep->security = sec_status_bogus;
return;
}
}
/* additional */
if(!ve->clean_additional)
return;
for(i=rep->an_numrrsets+rep->ns_numrrsets; i<rep->rrset_count; i++) {
if(((struct packed_rrset_data*)rep->rrsets[i]->entry.data)
->security != sec_status_secure) {
/* This does not cause message invalidation. It was
* simply unsigned data in the additional. The
* RRSIG must have been truncated off the message.
*
* However, we do not want to return possible bogus
* data to clients that rely on this service for
* their authentication.
*/
/* remove this unneeded additional rrset */
memmove(rep->rrsets+i, rep->rrsets+i+1,
sizeof(struct ub_packed_rrset_key*)*
(rep->rrset_count - i - 1));
rep->ar_numrrsets--;
rep->rrset_count--;
i--;
}
}
}
/** check no anchor and unlock */
static int
check_no_anchor(struct val_anchors* anchors, uint8_t* nm, size_t l, uint16_t c)
{
struct trust_anchor* ta;
if((ta=anchors_lookup(anchors, nm, l, c))) {
lock_basic_unlock(&ta->lock);
}
return !ta;
}
void
val_mark_indeterminate(struct reply_info* rep, struct val_anchors* anchors,
struct rrset_cache* r, struct module_env* env)
{
size_t i;
struct packed_rrset_data* d;
for(i=0; i<rep->rrset_count; i++) {
d = (struct packed_rrset_data*)rep->rrsets[i]->entry.data;
if(d->security == sec_status_unchecked &&
check_no_anchor(anchors, rep->rrsets[i]->rk.dname,
rep->rrsets[i]->rk.dname_len,
ntohs(rep->rrsets[i]->rk.rrset_class)))
{
/* mark as indeterminate */
d->security = sec_status_indeterminate;
rrset_update_sec_status(r, rep->rrsets[i], *env->now);
}
}
}
void
val_mark_insecure(struct reply_info* rep, uint8_t* kname,
struct rrset_cache* r, struct module_env* env)
{
size_t i;
struct packed_rrset_data* d;
for(i=0; i<rep->rrset_count; i++) {
d = (struct packed_rrset_data*)rep->rrsets[i]->entry.data;
if(d->security == sec_status_unchecked &&
dname_subdomain_c(rep->rrsets[i]->rk.dname, kname)) {
/* mark as insecure */
d->security = sec_status_insecure;
rrset_update_sec_status(r, rep->rrsets[i], *env->now);
}
}
}
size_t
val_next_unchecked(struct reply_info* rep, size_t skip)
{
size_t i;
struct packed_rrset_data* d;
for(i=skip+1; i<rep->rrset_count; i++) {
d = (struct packed_rrset_data*)rep->rrsets[i]->entry.data;
if(d->security == sec_status_unchecked) {
return i;
}
}
return rep->rrset_count;
}
const char*
val_classification_to_string(enum val_classification subtype)
{
switch(subtype) {
case VAL_CLASS_UNTYPED: return "untyped";
case VAL_CLASS_UNKNOWN: return "unknown";
case VAL_CLASS_POSITIVE: return "positive";
case VAL_CLASS_CNAME: return "cname";
case VAL_CLASS_NODATA: return "nodata";
case VAL_CLASS_NAMEERROR: return "nameerror";
case VAL_CLASS_CNAMENOANSWER: return "cnamenoanswer";
case VAL_CLASS_REFERRAL: return "referral";
case VAL_CLASS_ANY: return "qtype_any";
default:
return "bad_val_classification";
}
}
/** log a sock_list entry */
static void
sock_list_logentry(enum verbosity_value v, const char* s, struct sock_list* p)
{
if(p->len)
log_addr(v, s, &p->addr, p->len);
else verbose(v, "%s cache", s);
}
void val_blacklist(struct sock_list** blacklist, struct regional* region,
struct sock_list* origin, int cross)
{
/* debug printout */
if(verbosity >= VERB_ALGO) {
struct sock_list* p;
for(p=*blacklist; p; p=p->next)
sock_list_logentry(VERB_ALGO, "blacklist", p);
if(!origin)
verbose(VERB_ALGO, "blacklist add: cache");
for(p=origin; p; p=p->next)
sock_list_logentry(VERB_ALGO, "blacklist add", p);
}
/* blacklist the IPs or the cache */
if(!origin) {
/* only add if nothing there. anything else also stops cache*/
if(!*blacklist)
sock_list_insert(blacklist, NULL, 0, region);
} else if(!cross)
sock_list_prepend(blacklist, origin);
else sock_list_merge(blacklist, region, origin);
}
int val_has_signed_nsecs(struct reply_info* rep, char** reason)
{
size_t i, num_nsec = 0, num_nsec3 = 0;
struct packed_rrset_data* d;
for(i=rep->an_numrrsets; i<rep->an_numrrsets+rep->ns_numrrsets; i++) {
if(rep->rrsets[i]->rk.type == htons(LDNS_RR_TYPE_NSEC))
num_nsec++;
else if(rep->rrsets[i]->rk.type == htons(LDNS_RR_TYPE_NSEC3))
num_nsec3++;
else continue;
d = (struct packed_rrset_data*)rep->rrsets[i]->entry.data;
if(d && d->rrsig_count != 0) {
return 1;
}
}
if(num_nsec == 0 && num_nsec3 == 0)
*reason = "no DNSSEC records";
else if(num_nsec != 0)
*reason = "no signatures over NSECs";
else *reason = "no signatures over NSEC3s";
return 0;
}
struct dns_msg*
val_find_DS(struct module_env* env, uint8_t* nm, size_t nmlen, uint16_t c,
struct regional* region, uint8_t* topname)
{
struct dns_msg* msg;
struct query_info qinfo;
struct ub_packed_rrset_key *rrset = rrset_cache_lookup(
env->rrset_cache, nm, nmlen, LDNS_RR_TYPE_DS, c, 0,
*env->now, 0);
if(rrset) {
/* DS rrset exists. Return it to the validator immediately*/
struct ub_packed_rrset_key* copy = packed_rrset_copy_region(
rrset, region, *env->now);
lock_rw_unlock(&rrset->entry.lock);
if(!copy)
return NULL;
msg = dns_msg_create(nm, nmlen, LDNS_RR_TYPE_DS, c, region, 1);
if(!msg)
return NULL;
msg->rep->rrsets[0] = copy;
msg->rep->rrset_count++;
msg->rep->an_numrrsets++;
return msg;
}
/* lookup in rrset and negative cache for NSEC/NSEC3 */
qinfo.qname = nm;
qinfo.qname_len = nmlen;
qinfo.qtype = LDNS_RR_TYPE_DS;
qinfo.qclass = c;
qinfo.local_alias = NULL;
/* do not add SOA to reply message, it is going to be used internal */
msg = val_neg_getmsg(env->neg_cache, &qinfo, region, env->rrset_cache,
env->scratch_buffer, *env->now, 0, topname);
return msg;
}
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