static int update_delegation(struct kr_request *req, struct kr_query *qry, knot_pkt_t *answer, bool has_nsec3)
{
struct kr_zonecut *cut = &qry->zone_cut;
/* RFC4035 3.1.4. authoritative must send either DS or proof of non-existence.
* If it contains neither, the referral is bogus (or an attempted downgrade attack).
*/
unsigned section = KNOT_ANSWER;
if (!knot_wire_get_aa(answer->wire)) { /* Referral */
section = KNOT_AUTHORITY;
} else if (knot_pkt_qtype(answer) == KNOT_RRTYPE_DS) { /* Subrequest */
section = KNOT_ANSWER;
} else { /* N/A */
return kr_ok();
}
int ret = 0;
const knot_dname_t *proved_name = knot_pkt_qname(answer);
/* Aggregate DS records (if using multiple keys) */
knot_rrset_t *new_ds = update_ds(cut, knot_pkt_section(answer, section));
if (!new_ds) {
/* No DS provided, check for proof of non-existence. */
if (!has_nsec3) {
if (!knot_wire_get_aa(answer->wire)) {
/* Referral, check if it is referral to unsigned, rfc4035 5.2 */
ret = kr_nsec_ref_to_unsigned(answer);
} else {
/* No-data answer */
ret = kr_nsec_existence_denial(answer, KNOT_AUTHORITY, proved_name, KNOT_RRTYPE_DS);
}
} else {
if (!knot_wire_get_aa(answer->wire)) {
/* Referral, check if it is referral to unsigned, rfc5155 8.9 */
ret = kr_nsec3_ref_to_unsigned(answer);
} else {
/* No-data answer, QTYPE is DS, rfc5155 8.6 */
ret = kr_nsec3_no_data(answer, KNOT_AUTHORITY, proved_name, KNOT_RRTYPE_DS);
}
if (ret == kr_error(DNSSEC_NOT_FOUND)) {
/* Not bogus, going insecure due to optout */
ret = 0;
}
}
if (ret != 0) {
DEBUG_MSG(qry, "<= bogus proof of DS non-existence\n");
qry->flags |= QUERY_DNSSEC_BOGUS;
} else {
DEBUG_MSG(qry, "<= DS doesn't exist, going insecure\n");
qry->flags &= ~QUERY_DNSSEC_WANT;
qry->flags |= QUERY_DNSSEC_INSECURE;
}
return ret;
}
/* Extend trust anchor */
DEBUG_MSG(qry, "<= DS: OK\n");
cut->trust_anchor = new_ds;
return ret;
}
static int validate(knot_layer_t *ctx, knot_pkt_t *pkt)
{
int ret = 0;
struct kr_request *req = ctx->data;
struct kr_query *qry = req->current_query;
/* Ignore faulty or unprocessed responses. */
if (ctx->state & (KNOT_STATE_FAIL|KNOT_STATE_CONSUME)) {
return ctx->state;
}
/* Pass-through if user doesn't want secure answer or stub. */
/* @todo: Validating stub resolver mode. */
if (!(qry->flags & QUERY_DNSSEC_WANT) || (qry->flags & QUERY_STUB)) {
return ctx->state;
}
/* Answer for RRSIG may not set DO=1, but all records MUST still validate. */
bool use_signatures = (knot_pkt_qtype(pkt) != KNOT_RRTYPE_RRSIG);
if (!(qry->flags & QUERY_CACHED) && !knot_pkt_has_dnssec(pkt) && !use_signatures) {
DEBUG_MSG(qry, "<= got insecure response\n");
qry->flags |= QUERY_DNSSEC_BOGUS;
return KNOT_STATE_FAIL;
}
/* Track difference between current TA and signer name.
* This indicates that the NS is auth for both parent-child, and we must update DS/DNSKEY to validate it.
*/
const bool track_pc_change = (!(qry->flags & QUERY_CACHED) && (qry->flags & QUERY_DNSSEC_WANT));
const knot_dname_t *ta_name = qry->zone_cut.trust_anchor ? qry->zone_cut.trust_anchor->owner : NULL;
const knot_dname_t *signer = signature_authority(pkt);
if (track_pc_change && ta_name && (!signer || !knot_dname_is_equal(ta_name, signer))) {
if (ctx->state == KNOT_STATE_YIELD) { /* Already yielded for revalidation. */
return KNOT_STATE_FAIL;
}
DEBUG_MSG(qry, ">< cut changed, needs revalidation\n");
if (!signer) {
/* Not a DNSSEC-signed response, ask parent for DS to prove transition to INSECURE. */
} else if (knot_dname_is_sub(signer, qry->zone_cut.name)) {
/* Key signer is below current cut, advance and refetch keys. */
qry->zone_cut.name = knot_dname_copy(signer, &req->pool);
} else if (!knot_dname_is_equal(signer, qry->zone_cut.name)) {
/* Key signer is above the current cut, so we can't validate it. This happens when
a server is authoritative for both grandparent, parent and child zone.
Ascend to parent cut, and refetch authority for signer. */
if (qry->zone_cut.parent) {
memcpy(&qry->zone_cut, qry->zone_cut.parent, sizeof(qry->zone_cut));
} else {
qry->flags |= QUERY_AWAIT_CUT;
}
qry->zone_cut.name = knot_dname_copy(signer, &req->pool);
} /* else zone cut matches, but DS/DNSKEY doesn't => refetch. */
return KNOT_STATE_YIELD;
}
/* Check if this is a DNSKEY answer, check trust chain and store. */
uint8_t pkt_rcode = knot_wire_get_rcode(pkt->wire);
uint16_t qtype = knot_pkt_qtype(pkt);
bool has_nsec3 = pkt_has_type(pkt, KNOT_RRTYPE_NSEC3);
if (knot_wire_get_aa(pkt->wire) && qtype == KNOT_RRTYPE_DNSKEY) {
ret = validate_keyset(qry, pkt, has_nsec3);
if (ret != 0) {
DEBUG_MSG(qry, "<= bad keys, broken trust chain\n");
qry->flags |= QUERY_DNSSEC_BOGUS;
return KNOT_STATE_FAIL;
}
}
/* Validate non-existence proof if not positive answer. */
if (!(qry->flags & QUERY_CACHED) && pkt_rcode == KNOT_RCODE_NXDOMAIN) {
/* @todo If knot_pkt_qname(pkt) is used instead of qry->sname then the tests crash. */
if (!has_nsec3) {
ret = kr_nsec_name_error_response_check(pkt, KNOT_AUTHORITY, qry->sname);
} else {
ret = kr_nsec3_name_error_response_check(pkt, KNOT_AUTHORITY, qry->sname);
}
if (ret != 0) {
DEBUG_MSG(qry, "<= bad NXDOMAIN proof\n");
qry->flags |= QUERY_DNSSEC_BOGUS;
return KNOT_STATE_FAIL;
}
}
/* @todo WTH, this needs API that just tries to find a proof and the caller
* doesn't have to worry about NSEC/NSEC3
* @todo rework this */
if (!(qry->flags & QUERY_CACHED)) {
const knot_pktsection_t *an = knot_pkt_section(pkt, KNOT_ANSWER);
if (pkt_rcode == KNOT_RCODE_NOERROR && an->count == 0 && knot_wire_get_aa(pkt->wire)) {
/* @todo
* ? quick mechanism to determine which check to preform first
* ? merge the functionality together to share code/resources
*/
if (!has_nsec3) {
ret = kr_nsec_existence_denial(pkt, KNOT_AUTHORITY, knot_pkt_qname(pkt), knot_pkt_qtype(pkt));
} else {
ret = kr_nsec3_no_data(pkt, KNOT_AUTHORITY, knot_pkt_qname(pkt), knot_pkt_qtype(pkt));
}
if (ret != 0) {
if (has_nsec3 && (ret == kr_error(DNSSEC_NOT_FOUND))) {
DEBUG_MSG(qry, "<= can't prove NODATA due to optout, going insecure\n");
qry->flags &= ~QUERY_DNSSEC_WANT;
qry->flags |= QUERY_DNSSEC_INSECURE;
} else {
DEBUG_MSG(qry, "<= bad NODATA proof\n");
qry->flags |= QUERY_DNSSEC_BOGUS;
return KNOT_STATE_FAIL;
}
}
}
}
/* Validate all records, fail as bogus if it doesn't match.
* Do not revalidate data from cache, as it's already trusted. */
if (!(qry->flags & QUERY_CACHED)) {
ret = validate_records(qry, pkt, req->rplan.pool, has_nsec3);
if (ret != 0) {
DEBUG_MSG(qry, "<= couldn't validate RRSIGs\n");
qry->flags |= QUERY_DNSSEC_BOGUS;
return KNOT_STATE_FAIL;
}
}
/* Check if wildcard expansion detected for final query.
* If yes, copy authority. */
if ((qry->parent == NULL) && (qry->flags & QUERY_DNSSEC_WEXPAND)) {
const knot_pktsection_t *auth = knot_pkt_section(pkt, KNOT_AUTHORITY);
for (unsigned i = 0; i < auth->count; ++i) {
const knot_rrset_t *rr = knot_pkt_rr(auth, i);
kr_rrarray_add(&req->authority, rr, &req->answer->mm);
}
}
/* Check and update current delegation point security status. */
ret = update_delegation(req, qry, pkt, has_nsec3);
if (ret != 0) {
return KNOT_STATE_FAIL;
}
/* Update parent query zone cut */
if (qry->parent) {
if (update_parent_keys(qry, qtype) != 0) {
return KNOT_STATE_FAIL;
}
}
DEBUG_MSG(qry, "<= answer valid, OK\n");
return KNOT_STATE_DONE;
}
static void print_header(const knot_pkt_t *packet, const style_t *style,
const uint16_t ext_rcode)
{
char flags[64] = "";
uint8_t opcode_id;
const char *rcode_str = "Unknown";
const char *opcode_str = "Unknown";
lookup_table_t *rcode, *opcode;
// Get RCODE from Header and check for Extended RCODE from OPT RR.
rcode = lookup_by_id(knot_rcode_names, ext_rcode);
if (rcode != NULL) {
rcode_str = rcode->name;
}
// Get OPCODE.
opcode_id = knot_wire_get_opcode(packet->wire);
opcode = lookup_by_id(knot_opcode_names, opcode_id);
if (opcode != NULL) {
opcode_str = opcode->name;
}
// Get flags.
size_t flags_rest = sizeof(flags);
const size_t flag_len = 4;
if (knot_wire_get_qr(packet->wire) != 0 && flags_rest > flag_len) {
flags_rest -= strlcat(flags, " qr", flags_rest);
}
if (knot_wire_get_aa(packet->wire) != 0 && flags_rest > flag_len) {
flags_rest -= strlcat(flags, " aa", flags_rest);
}
if (knot_wire_get_tc(packet->wire) != 0 && flags_rest > flag_len) {
flags_rest -= strlcat(flags, " tc", flags_rest);
}
if (knot_wire_get_rd(packet->wire) != 0 && flags_rest > flag_len) {
flags_rest -= strlcat(flags, " rd", flags_rest);
}
if (knot_wire_get_ra(packet->wire) != 0 && flags_rest > flag_len) {
flags_rest -= strlcat(flags, " ra", flags_rest);
}
if (knot_wire_get_z(packet->wire) != 0 && flags_rest > flag_len) {
flags_rest -= strlcat(flags, " z", flags_rest);
}
if (knot_wire_get_ad(packet->wire) != 0 && flags_rest > flag_len) {
flags_rest -= strlcat(flags, " ad", flags_rest);
}
if (knot_wire_get_cd(packet->wire) != 0 && flags_rest > flag_len) {
strlcat(flags, " cd", flags_rest);
}
uint16_t id = knot_wire_get_id(packet->wire);
uint16_t qdcount = knot_wire_get_qdcount(packet->wire);
uint16_t ancount = knot_wire_get_ancount(packet->wire);
uint16_t nscount = knot_wire_get_nscount(packet->wire);
uint16_t arcount = knot_wire_get_arcount(packet->wire);
if (knot_pkt_has_tsig(packet)) {
arcount++;
}
// Print formatted info.
switch (style->format) {
case FORMAT_NSUPDATE:
printf(";; ->>HEADER<<- opcode: %s; status: %s; id: %u\n"
";; Flags:%1s; "
"ZONE: %u; PREREQ: %u; UPDATE: %u; ADDITIONAL: %u\n",
opcode_str, rcode_str, id, flags, qdcount, ancount,
nscount, arcount);
break;
default:
printf(";; ->>HEADER<<- opcode: %s; status: %s; id: %u\n"
";; Flags:%1s; "
"QUERY: %u; ANSWER: %u; AUTHORITY: %u; ADDITIONAL: %u\n",
opcode_str, rcode_str, id, flags, qdcount, ancount,
nscount, arcount);
break;
}
}
