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-rw-r--r--lib/layer/validate.c1366
1 files changed, 1366 insertions, 0 deletions
diff --git a/lib/layer/validate.c b/lib/layer/validate.c
new file mode 100644
index 0000000..93f1d4f
--- /dev/null
+++ b/lib/layer/validate.c
@@ -0,0 +1,1366 @@
+/* Copyright (C) CZ.NIC, z.s.p.o. <knot-resolver@labs.nic.cz>
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+#include <errno.h>
+#include <sys/time.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <contrib/cleanup.h>
+#include <libknot/packet/wire.h>
+#include <libknot/rrtype/rdname.h>
+#include <libknot/rrtype/rrsig.h>
+#include <libdnssec/error.h>
+
+#include "lib/dnssec/nsec.h"
+#include "lib/dnssec/nsec3.h"
+#include "lib/dnssec/ta.h"
+#include "lib/dnssec.h"
+#include "lib/layer.h"
+#include "lib/resolve.h"
+#include "lib/rplan.h"
+#include "lib/utils.h"
+#include "lib/defines.h"
+#include "lib/module.h"
+#include "lib/selection.h"
+
+#define VERBOSE_MSG(qry, ...) kr_log_q(qry, VALIDATOR, __VA_ARGS__)
+
+#define MAX_REVALIDATION_CNT 2
+
+/**
+ * Search in section for given type.
+ * @param sec Packet section.
+ * @param type Type to search for.
+ * @return True if found.
+ */
+static bool section_has_type(const knot_pktsection_t *sec, uint16_t type)
+{
+ if (!sec) {
+ return false;
+ }
+
+ for (unsigned i = 0; i < sec->count; ++i) {
+ const knot_rrset_t *rr = knot_pkt_rr(sec, i);
+ if (rr->type == type) {
+ return true;
+ }
+ }
+
+ return false;
+}
+
+static bool pkt_has_type(const knot_pkt_t *pkt, uint16_t type)
+{
+ if (!pkt) {
+ return false;
+ }
+
+ if (section_has_type(knot_pkt_section(pkt, KNOT_ANSWER), type)) {
+ return true;
+ }
+ if (section_has_type(knot_pkt_section(pkt, KNOT_AUTHORITY), type)) {
+ return true;
+ }
+ return section_has_type(knot_pkt_section(pkt, KNOT_ADDITIONAL), type);
+}
+
+static void log_bogus_rrsig(kr_rrset_validation_ctx_t *vctx,
+ const knot_rrset_t *rr, const char *msg) {
+ if (kr_log_is_debug_qry(VALIDATOR, vctx->log_qry)) {
+ auto_free char *name_text = kr_dname_text(rr->owner);
+ auto_free char *type_text = kr_rrtype_text(rr->type);
+ VERBOSE_MSG(vctx->log_qry, ">< %s: %s %s "
+ "(%u matching RRSIGs, %u expired, %u not yet valid, "
+ "%u invalid signer, %u invalid label count, %u invalid key, "
+ "%u invalid crypto, %u invalid NSEC)\n",
+ msg, name_text, type_text, vctx->rrs_counters.matching_name_type,
+ vctx->rrs_counters.expired, vctx->rrs_counters.notyet,
+ vctx->rrs_counters.signer_invalid, vctx->rrs_counters.labels_invalid,
+ vctx->rrs_counters.key_invalid, vctx->rrs_counters.crypto_invalid,
+ vctx->rrs_counters.nsec_invalid);
+ }
+}
+
+/** Check that given CNAME could be generated by given DNAME (no DNSSEC validation). */
+static bool cname_matches_dname(const knot_rrset_t *rr_cn, const knot_rrset_t *rr_dn)
+{
+ if (kr_fails_assert(rr_cn->type == KNOT_RRTYPE_CNAME && rr_dn->type == KNOT_RRTYPE_DNAME))
+ return false;
+ /* When DNAME substitution happens, let's consider the "prefix"
+ * that is carried over and the "suffix" that is replaced.
+ * (Here we consider the label order used in wire and presentation.) */
+ const int prefix_labels = knot_dname_in_bailiwick(rr_cn->owner, rr_dn->owner);
+ if (prefix_labels < 1)
+ return false;
+ const knot_dname_t *cn_target = knot_cname_name(rr_cn->rrs.rdata);
+ const knot_dname_t *dn_target = knot_dname_target(rr_dn->rrs.rdata);
+ /* ^ We silently use the first RR in each RRset. Could be e.g. logged. */
+ /* Check that the suffixes are correct - and even prefix label counts. */
+ if (knot_dname_in_bailiwick(cn_target, dn_target) != prefix_labels)
+ return false;
+ /* Check that prefixes match. Find end of the first one and compare. */
+ const knot_dname_t *cn_se = rr_cn->owner;
+ for (int i = 0; i < prefix_labels; ++i)
+ cn_se += 1 + *cn_se;
+ return strncmp((const char *)rr_cn->owner, (const char *)cn_target,
+ cn_se - rr_cn->owner) == 0;
+ /* ^ We use the fact that dnames are always zero-terminated
+ * to avoid any possible over-read in cn_target. */
+}
+
+static void mark_insecure_parents(const struct kr_query *qry);
+static void rank_records(struct kr_query *qry, bool any_rank, enum kr_rank rank_to_set,
+ const knot_dname_t *bailiwick);
+
+static bool maybe_downgrade_nsec3(const ranked_rr_array_entry_t *e, struct kr_query *qry,
+ const kr_rrset_validation_ctx_t *vctx)
+{
+ bool required_conditions =
+ e->rr->type == KNOT_RRTYPE_NSEC3
+ && kr_rank_test(e->rank, KR_RANK_SECURE)
+ // extra careful: avoid downgrade if SNAME isn't in bailiwick of signer
+ && knot_dname_in_bailiwick(qry->sname, vctx->zone_name) >= 0;
+ if (!required_conditions)
+ return false;
+
+ const knot_rdataset_t *rrs = &e->rr->rrs;
+ knot_rdata_t *rd = rrs->rdata;
+ for (int j = 0; j < rrs->count; ++j, rd = knot_rdataset_next(rd)) {
+ if (knot_nsec3_iters(rd) > KR_NSEC3_MAX_ITERATIONS)
+ goto do_downgrade;
+ }
+ return false;
+
+do_downgrade: // we do this deep inside calls because of having signer name available
+ VERBOSE_MSG(qry, "<= DNSSEC downgraded due to NSEC3 iterations %d > %d\n",
+ (int)knot_nsec3_iters(rd), (int)KR_NSEC3_MAX_ITERATIONS);
+ qry->flags.DNSSEC_WANT = false;
+ qry->flags.DNSSEC_INSECURE = true;
+ rank_records(qry, true, KR_RANK_INSECURE, vctx->zone_name);
+ mark_insecure_parents(qry);
+ return true;
+}
+
+#define KNOT_EDOWNGRADED (KNOT_ERROR_MIN - 1)
+
+static int validate_section(kr_rrset_validation_ctx_t *vctx, struct kr_query *qry,
+ knot_mm_t *pool)
+{
+ struct kr_request *req = qry->request;
+ if (!vctx) {
+ return kr_error(EINVAL);
+ }
+
+ /* Can't use qry->zone_cut.name directly, as this name can
+ * change when updating cut information before validation.
+ */
+ vctx->zone_name = vctx->keys ? vctx->keys->owner : NULL;
+
+ for (ssize_t i = 0; i < vctx->rrs->len; ++i) {
+ ranked_rr_array_entry_t *entry = vctx->rrs->at[i];
+ knot_rrset_t * const rr = entry->rr;
+
+ if (entry->yielded || vctx->qry_uid != entry->qry_uid) {
+ continue;
+ }
+
+ if (kr_rank_test(entry->rank, KR_RANK_OMIT)
+ || kr_rank_test(entry->rank, KR_RANK_SECURE)) {
+ continue; /* these are already OK */
+ }
+
+ if (!knot_dname_is_equal(qry->zone_cut.name, rr->owner)/*optim.*/
+ && !kr_ta_closest(qry->request->ctx, rr->owner, rr->type)) {
+ /* We have NTA "between" our (perceived) zone cut and the RR. */
+ kr_rank_set(&entry->rank, KR_RANK_INSECURE);
+ continue;
+ }
+
+ if (rr->type == KNOT_RRTYPE_RRSIG) {
+ const knot_dname_t *signer_name = knot_rrsig_signer_name(rr->rrs.rdata);
+ if (!knot_dname_is_equal(vctx->zone_name, signer_name)) {
+ kr_rank_set(&entry->rank, KR_RANK_MISMATCH);
+ vctx->err_cnt += 1;
+ break;
+ }
+ if (!kr_rank_test(entry->rank, KR_RANK_BOGUS))
+ kr_rank_set(&entry->rank, KR_RANK_OMIT);
+ continue;
+ }
+
+ uint8_t rank_orig = entry->rank;
+ int validation_result = kr_rrset_validate(vctx, rr);
+
+ /* Handle the case of CNAMEs synthesized from DNAMEs (they don't have RRSIGs). */
+ if (rr->type == KNOT_RRTYPE_CNAME && validation_result == kr_error(ENOENT)) {
+ for (ssize_t j = 0; j < vctx->rrs->len; ++j) {
+ ranked_rr_array_entry_t *e_dname = vctx->rrs->at[j];
+ if ((e_dname->rr->type == KNOT_RRTYPE_DNAME)
+ /* If the order is wrong, we will need two passes. */
+ && kr_rank_test(e_dname->rank, KR_RANK_SECURE)
+ && cname_matches_dname(rr, e_dname->rr)) {
+ /* Now we believe the CNAME is OK. */
+ validation_result = kr_ok();
+ break;
+ }
+ }
+ if (validation_result != kr_ok()) {
+ vctx->cname_norrsig_cnt += 1;
+ }
+ }
+
+ if (validation_result == kr_ok()) {
+ kr_rank_set(&entry->rank, KR_RANK_SECURE);
+
+ /* Downgrade zone to insecure if certain NSEC3 record occurs. */
+ if (unlikely(maybe_downgrade_nsec3(entry, qry, vctx)))
+ return kr_error(KNOT_EDOWNGRADED);
+
+ } else if (kr_rank_test(rank_orig, KR_RANK_TRY)) {
+ /* RFC 4035 section 2.2:
+ * NS RRsets that appear at delegation points (...)
+ * MUST NOT be signed */
+ if (vctx->rrs_counters.matching_name_type > 0)
+ log_bogus_rrsig(vctx, rr,
+ "found unexpected signatures for non-authoritative data which failed to validate, continuing");
+ vctx->result = kr_ok();
+ kr_rank_set(&entry->rank, KR_RANK_TRY);
+ /* ^^ BOGUS would be more accurate, but it might change
+ * to MISMATCH on revalidation, e.g. in test val_referral_nods :-/
+ */
+
+ } else if (validation_result == kr_error(ENOENT)
+ && vctx->rrs_counters.matching_name_type == 0) {
+ /* no RRSIGs found */
+ kr_rank_set(&entry->rank, KR_RANK_MISSING);
+ vctx->err_cnt += 1;
+ kr_request_set_extended_error(req, KNOT_EDNS_EDE_RRSIG_MISS, "JZAJ");
+ log_bogus_rrsig(vctx, rr, "no valid RRSIGs found");
+ } else {
+ kr_rank_set(&entry->rank, KR_RANK_BOGUS);
+ vctx->err_cnt += 1;
+ if (vctx->rrs_counters.expired > 0)
+ kr_request_set_extended_error(req, KNOT_EDNS_EDE_SIG_EXPIRED, "YFJ2");
+ else if (vctx->rrs_counters.notyet > 0)
+ kr_request_set_extended_error(req, KNOT_EDNS_EDE_SIG_NOTYET, "UBBS");
+ else
+ kr_request_set_extended_error(req, KNOT_EDNS_EDE_BOGUS, "I74V");
+ log_bogus_rrsig(vctx, rr, "bogus signatures");
+ }
+ }
+ return kr_ok();
+}
+
+static int validate_records(struct kr_request *req, knot_pkt_t *answer, knot_mm_t *pool, bool has_nsec3)
+{
+ struct kr_query *qry = req->current_query;
+ if (!qry->zone_cut.key) {
+ VERBOSE_MSG(qry, "<= no DNSKEY, can't validate\n");
+ return kr_error(EBADMSG);
+ }
+
+ kr_rrset_validation_ctx_t vctx = {
+ .pkt = answer,
+ .rrs = &req->answ_selected,
+ .section_id = KNOT_ANSWER,
+ .keys = qry->zone_cut.key,
+ .zone_name = qry->zone_cut.name,
+ .timestamp = qry->timestamp.tv_sec,
+ .ttl_min = req->ctx->cache.ttl_min,
+ .qry_uid = qry->uid,
+ .has_nsec3 = has_nsec3,
+ .flags = 0,
+ .err_cnt = 0,
+ .cname_norrsig_cnt = 0,
+ .result = 0,
+ .log_qry = qry,
+ };
+
+ int ret = validate_section(&vctx, qry, pool);
+ if (vctx.err_cnt && vctx.err_cnt == vctx.cname_norrsig_cnt) {
+ VERBOSE_MSG(qry, ">< all validation errors are missing RRSIGs on CNAMES, trying again in hope for DNAMEs\n");
+ vctx.err_cnt = vctx.cname_norrsig_cnt = vctx.result = 0;
+ ret = validate_section(&vctx, qry, pool);
+ }
+ req->answ_validated = (vctx.err_cnt == 0);
+ if (ret != kr_ok()) {
+ return ret;
+ }
+
+ uint32_t an_flags = vctx.flags;
+ vctx.rrs = &req->auth_selected;
+ vctx.section_id = KNOT_AUTHORITY;
+ vctx.flags = 0;
+ vctx.err_cnt = 0;
+ vctx.result = 0;
+
+ ret = validate_section(&vctx, qry, pool);
+ req->auth_validated = (vctx.err_cnt == 0);
+ if (ret != kr_ok()) {
+ return ret;
+ }
+
+ /* Records were validated.
+ * If there is wildcard expansion in answer,
+ * or optout - flag the query.
+ */
+ if (an_flags & KR_DNSSEC_VFLG_WEXPAND) {
+ qry->flags.DNSSEC_WEXPAND = true;
+ }
+ if (an_flags & KR_DNSSEC_VFLG_OPTOUT) {
+ qry->flags.DNSSEC_OPTOUT = true;
+ }
+
+ return ret;
+}
+
+static int validate_keyset(struct kr_request *req, knot_pkt_t *answer, bool has_nsec3)
+{
+ /* Merge DNSKEY records from answer that are below/at current cut. */
+ struct kr_query *qry = req->current_query;
+ bool updated_key = false;
+ const knot_pktsection_t *an = knot_pkt_section(answer, KNOT_ANSWER);
+ for (unsigned i = 0; i < an->count; ++i) {
+ const knot_rrset_t *rr = knot_pkt_rr(an, i);
+ if (rr->type != KNOT_RRTYPE_DNSKEY
+ || knot_dname_in_bailiwick(rr->owner, qry->zone_cut.name) < 0) {
+ continue;
+ }
+ /* Merge with zone cut (or replace ancestor key). */
+ if (!qry->zone_cut.key || !knot_dname_is_equal(qry->zone_cut.key->owner, rr->owner)) {
+ qry->zone_cut.key = knot_rrset_copy(rr, qry->zone_cut.pool);
+ if (!qry->zone_cut.key) {
+ return kr_error(ENOMEM);
+ }
+ updated_key = true;
+ } else {
+ int ret = knot_rdataset_merge(&qry->zone_cut.key->rrs,
+ &rr->rrs, qry->zone_cut.pool);
+ if (ret != 0) {
+ knot_rrset_free(qry->zone_cut.key, qry->zone_cut.pool);
+ qry->zone_cut.key = NULL;
+ return ret;
+ }
+ updated_key = true;
+ }
+ }
+
+ /* Check if there's a key for current TA. */
+ if (updated_key && !(qry->flags.CACHED)) {
+ /* Find signatures for the DNSKEY; selected by iterator from ANSWER. */
+ int sig_index = -1;
+ for (int i = req->answ_selected.len - 1; i >= 0; --i) {
+ const knot_rrset_t *rrsig = req->answ_selected.at[i]->rr;
+ const bool ok = req->answ_selected.at[i]->qry_uid == qry->uid
+ && rrsig->type == KNOT_RRTYPE_RRSIG
+ && knot_rrsig_type_covered(rrsig->rrs.rdata)
+ == KNOT_RRTYPE_DNSKEY
+ && rrsig->rclass == KNOT_CLASS_IN
+ && knot_dname_is_equal(rrsig->owner,
+ qry->zone_cut.key->owner);
+ if (ok) {
+ sig_index = i;
+ break;
+ }
+ }
+ if (sig_index < 0) {
+ kr_request_set_extended_error(req, KNOT_EDNS_EDE_RRSIG_MISS, "EZDC");
+ return kr_error(ENOENT);
+ }
+ const knot_rdataset_t *sig_rds = &req->answ_selected.at[sig_index]->rr->rrs;
+
+ kr_rrset_validation_ctx_t vctx = {
+ .pkt = answer,
+ .rrs = &req->answ_selected,
+ .section_id = KNOT_ANSWER,
+ .keys = qry->zone_cut.key,
+ .zone_name = qry->zone_cut.name,
+ .timestamp = qry->timestamp.tv_sec,
+ .ttl_min = req->ctx->cache.ttl_min,
+ .qry_uid = qry->uid,
+ .has_nsec3 = has_nsec3,
+ .flags = 0,
+ .result = 0,
+ .log_qry = qry,
+ };
+ int ret = kr_dnskeys_trusted(&vctx, sig_rds, qry->zone_cut.trust_anchor);
+ /* Set rank of the RRSIG. This may be needed, but I don't know why.
+ * In particular, black_ent.rpl may get broken otherwise. */
+ kr_rank_set(&req->answ_selected.at[sig_index]->rank,
+ ret == 0 ? KR_RANK_SECURE : KR_RANK_BOGUS);
+
+ if (ret != 0) {
+ log_bogus_rrsig(&vctx, qry->zone_cut.key, "bogus key");
+ knot_rrset_free(qry->zone_cut.key, qry->zone_cut.pool);
+ qry->zone_cut.key = NULL;
+ if (vctx.rrs_counters.expired > 0)
+ kr_request_set_extended_error(req, KNOT_EDNS_EDE_SIG_EXPIRED, "6GJV");
+ else if (vctx.rrs_counters.notyet > 0)
+ kr_request_set_extended_error(req, KNOT_EDNS_EDE_SIG_NOTYET, "4DJQ");
+ else
+ kr_request_set_extended_error(req, KNOT_EDNS_EDE_BOGUS, "EXRU");
+ return ret;
+ }
+
+ if (vctx.flags & KR_DNSSEC_VFLG_WEXPAND) {
+ qry->flags.DNSSEC_WEXPAND = true;
+ }
+ if (vctx.flags & KR_DNSSEC_VFLG_OPTOUT) {
+ qry->flags.DNSSEC_OPTOUT = true;
+ }
+
+ }
+ return kr_ok();
+}
+
+static knot_rrset_t *update_ds(struct kr_zonecut *cut, const knot_pktsection_t *sec)
+{
+ /* Aggregate DS records (if using multiple keys) */
+ knot_rrset_t *new_ds = NULL;
+ for (unsigned i = 0; i < sec->count; ++i) {
+ const knot_rrset_t *rr = knot_pkt_rr(sec, i);
+ if (rr->type != KNOT_RRTYPE_DS) {
+ continue;
+ }
+ int ret = 0;
+ if (new_ds) {
+ ret = knot_rdataset_merge(&new_ds->rrs, &rr->rrs, cut->pool);
+ } else {
+ new_ds = knot_rrset_copy(rr, cut->pool);
+ if (!new_ds) {
+ return NULL;
+ }
+ }
+ if (ret != 0) {
+ knot_rrset_free(new_ds, cut->pool);
+ return NULL;
+ }
+ }
+ return new_ds;
+}
+
+static void mark_insecure_parents(const struct kr_query *qry)
+{
+ /* If there is a chain of DS queries mark all of them,
+ * then mark first non-DS parent.
+ * Stop if parent is waiting for ns address.
+ * NS can be located at unsigned zone, but still will return
+ * valid DNSSEC records for initial query. */
+ struct kr_query *parent = qry->parent;
+ while (parent && !parent->flags.AWAIT_IPV4 && !parent->flags.AWAIT_IPV6) {
+ parent->flags.DNSSEC_WANT = false;
+ parent->flags.DNSSEC_INSECURE = true;
+ if (parent->stype != KNOT_RRTYPE_DS &&
+ parent->stype != KNOT_RRTYPE_RRSIG) {
+ break;
+ }
+ parent = parent->parent;
+ }
+}
+
+static int update_parent_keys(struct kr_request *req, uint16_t answer_type)
+{
+ struct kr_query *qry = req->current_query;
+ struct kr_query *parent = qry->parent;
+ if (kr_fails_assert(parent))
+ return KR_STATE_FAIL;
+ switch(answer_type) {
+ case KNOT_RRTYPE_DNSKEY:
+ VERBOSE_MSG(qry, "<= parent: updating DNSKEY\n");
+ parent->zone_cut.key = knot_rrset_copy(qry->zone_cut.key, parent->zone_cut.pool);
+ if (!parent->zone_cut.key) {
+ return KR_STATE_FAIL;
+ }
+ break;
+ case KNOT_RRTYPE_DS:
+ VERBOSE_MSG(qry, "<= parent: updating DS\n");
+ if (qry->flags.DNSSEC_INSECURE) { /* DS non-existence proven. */
+ mark_insecure_parents(qry);
+ } else if (qry->flags.DNSSEC_NODS && !qry->flags.FORWARD) {
+ if (qry->flags.DNSSEC_OPTOUT) {
+ mark_insecure_parents(qry);
+ } else {
+ int ret = kr_dnssec_matches_name_and_type(&req->auth_selected, qry->uid,
+ qry->sname, KNOT_RRTYPE_NS);
+ if (ret == kr_ok()) {
+ mark_insecure_parents(qry);
+ }
+ }
+ } else if (qry->flags.DNSSEC_NODS && qry->flags.FORWARD) {
+ int ret = kr_dnssec_matches_name_and_type(&req->auth_selected, qry->uid,
+ qry->sname, KNOT_RRTYPE_NS);
+ if (ret == kr_ok()) {
+ mark_insecure_parents(qry);
+ }
+ } else { /* DS existence proven. */
+ parent->zone_cut.trust_anchor = knot_rrset_copy(qry->zone_cut.trust_anchor, parent->zone_cut.pool);
+ if (!parent->zone_cut.trust_anchor) {
+ return KR_STATE_FAIL;
+ }
+ }
+ break;
+ default: break;
+ }
+ return kr_ok();
+}
+
+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, resolver must query the parent for the DS (RFC4035 5.2.).
+ * If DS exists, the referral is OK,
+ * otherwise referral is bogus (or an attempted downgrade attack).
+ */
+
+
+ unsigned section = KNOT_ANSWER;
+ const bool referral = !knot_wire_get_aa(answer->wire);
+ if (referral) {
+ section = KNOT_AUTHORITY;
+ } else if (knot_pkt_qtype(answer) == KNOT_RRTYPE_DS &&
+ !(qry->flags.CNAME) &&
+ (knot_wire_get_rcode(answer->wire) != KNOT_RCODE_NXDOMAIN)) {
+ 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 (referral) {
+ /* Check if it is referral to unsigned, rfc4035 5.2 */
+ ret = kr_nsec_ref_to_unsigned(&req->auth_selected,
+ qry->uid, proved_name);
+ } else {
+ /* No-data answer */
+ ret = kr_nsec_negative(&req->auth_selected, qry->uid,
+ proved_name, KNOT_RRTYPE_DS);
+ if (ret >= 0) {
+ if (ret == PKT_NODATA) {
+ ret = kr_ok();
+ } else {
+ ret = kr_error(ENOENT); // suspicious
+ }
+ }
+ }
+ } else {
+ if (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(KNOT_ERANGE)) {
+ /* Not bogus, going insecure due to optout */
+ ret = 0;
+ }
+ }
+
+ if (referral && qry->stype != KNOT_RRTYPE_DS &&
+ ret == DNSSEC_NOT_FOUND) {
+ /* referral,
+ * qtype is not KNOT_RRTYPE_DS, NSEC\NSEC3 were not found.
+ * Check if DS already was fetched. */
+ knot_rrset_t *ta = cut->trust_anchor;
+ if (knot_dname_is_equal(cut->name, ta->owner)) {
+ /* DS is OK */
+ ret = 0;
+ }
+ } else if (ret != 0) {
+ VERBOSE_MSG(qry, "<= bogus proof of DS non-existence\n");
+ kr_request_set_extended_error(req, KNOT_EDNS_EDE_BOGUS, "Z4I6");
+ qry->flags.DNSSEC_BOGUS = true;
+ } else if (proved_name[0] != '\0') { /* don't go to insecure for . DS */
+ qry->flags.DNSSEC_NODS = true;
+ /* Rank the corresponding nonauth NS as insecure. */
+ for (int i = 0; i < req->auth_selected.len; ++i) {
+ ranked_rr_array_entry_t *ns = req->auth_selected.at[i];
+ if (ns->qry_uid != qry->uid
+ || !ns->rr
+ || ns->rr->type != KNOT_RRTYPE_NS) {
+ continue;
+ }
+ if (!referral && !knot_dname_is_equal(qry->sname, ns->rr->owner)) {
+ continue;
+ }
+ /* Found the record. Note: this is slightly fragile
+ * in case there were more NS records in the packet.
+ * As it is now for referrals, kr_nsec*_ref_to_unsigned consider
+ * (only) the first NS record in the packet. */
+ if (!kr_rank_test(ns->rank, KR_RANK_AUTH)) { /* sanity */
+ ns->rank = KR_RANK_INSECURE;
+ }
+ break;
+ }
+ }
+ return ret;
+ } else if (qry->flags.FORWARD && qry->parent) {
+ struct kr_query *parent = qry->parent;
+ parent->zone_cut.name = knot_dname_copy(qry->sname, parent->zone_cut.pool);
+ }
+
+ /* Extend trust anchor */
+ VERBOSE_MSG(qry, "<= DS: OK\n");
+ cut->trust_anchor = new_ds;
+ return ret;
+}
+
+static const knot_dname_t *find_first_signer(ranked_rr_array_t *arr, struct kr_query *qry)
+{
+ for (size_t i = 0; i < arr->len; ++i) {
+ ranked_rr_array_entry_t *entry = arr->at[i];
+ const knot_rrset_t *rr = entry->rr;
+ if (entry->yielded ||
+ (!kr_rank_test(entry->rank, KR_RANK_INITIAL) &&
+ !kr_rank_test(entry->rank, KR_RANK_TRY) &&
+ !kr_rank_test(entry->rank, KR_RANK_MISMATCH))) {
+ continue;
+ }
+ if (rr->type != KNOT_RRTYPE_RRSIG) {
+ continue;
+ }
+ const knot_dname_t *signame = knot_rrsig_signer_name(rr->rrs.rdata);
+ if (knot_dname_in_bailiwick(rr->owner, signame) >= 0) {
+ return signame;
+ } else {
+ /* otherwise it's some nonsense, so we skip it */
+ kr_log_q(qry, VALIDATOR, "protocol violation: "
+ "out-of-bailiwick RRSIG signer, skipping\n");
+ }
+ }
+ return NULL;
+}
+
+static const knot_dname_t *signature_authority(struct kr_request *req)
+{
+ const knot_dname_t *signer_name = find_first_signer(&req->answ_selected, req->current_query);
+ if (!signer_name) {
+ signer_name = find_first_signer(&req->auth_selected, req->current_query);
+ }
+ return signer_name;
+}
+
+static int rrsig_not_found(const kr_layer_t * const ctx, const knot_pkt_t * const pkt,
+ const knot_rrset_t * const rr)
+{
+ /* Signatures are missing. There might be a zone cut that we've skipped
+ * and transitions to insecure. That can commonly happen when iterating
+ * and both sides of that cut are served by the same IP address(es).
+ * We'll try proving that the name truly is insecure - by spawning
+ * a DS sub-query on a suitable QNAME.
+ */
+ struct kr_request * const req = ctx->req;
+ struct kr_query * const qry = req->current_query;
+
+ if (qry->flags.FORWARD || qry->flags.STUB) {
+ /* Undiscovered signed cuts can't happen in the current forwarding
+ * algorithm, so this function shouldn't be able to help. */
+ return KR_STATE_FAIL;
+ }
+
+ /* Find cut_next: the name at which to try finding the "missing" zone cut. */
+ const knot_dname_t * const cut_top = qry->zone_cut.name;
+ const int next_depth = knot_dname_in_bailiwick(rr->owner, cut_top);
+ if (next_depth <= 0) {
+ return KR_STATE_FAIL; // shouldn't happen, I think
+ }
+ /* Add one extra label to cur_top, i.e. descend one level below current zone cut */
+ const knot_dname_t * const cut_next = rr->owner +
+ knot_dname_prefixlen(rr->owner, next_depth - 1, NULL);
+
+ /* Spawn that DS sub-query. */
+ struct kr_query * const next = kr_rplan_push(&req->rplan, qry, cut_next,
+ rr->rclass, KNOT_RRTYPE_DS);
+ if (!next) {
+ return KR_STATE_FAIL;
+ }
+ kr_zonecut_init(&next->zone_cut, qry->zone_cut.name, &req->pool);
+ kr_zonecut_copy(&next->zone_cut, &qry->zone_cut);
+ kr_zonecut_copy_trust(&next->zone_cut, &qry->zone_cut);
+ next->flags.DNSSEC_WANT = true;
+ return KR_STATE_YIELD;
+}
+
+static int check_validation_result(kr_layer_t *ctx, const knot_pkt_t *pkt, ranked_rr_array_t *arr)
+{
+ int ret = KR_STATE_DONE;
+ struct kr_request *req = ctx->req;
+ struct kr_query *qry = req->current_query;
+ ranked_rr_array_entry_t *invalid_entry = NULL;
+ for (size_t i = 0; i < arr->len; ++i) {
+ ranked_rr_array_entry_t *entry = arr->at[i];
+ if (entry->yielded || entry->qry_uid != qry->uid) {
+ continue;
+ }
+ if (kr_rank_test(entry->rank, KR_RANK_MISMATCH)) {
+ invalid_entry = entry;
+ break;
+ } else if (kr_rank_test(entry->rank, KR_RANK_MISSING) &&
+ !invalid_entry) {
+ invalid_entry = entry;
+ } else if (kr_rank_test(entry->rank, KR_RANK_OMIT)) {
+ continue;
+ } else if (!kr_rank_test(entry->rank, KR_RANK_SECURE) &&
+ !invalid_entry) {
+ invalid_entry = entry;
+ }
+ }
+
+ if (!invalid_entry) {
+ return ret;
+ }
+
+ if (!kr_rank_test(invalid_entry->rank, KR_RANK_SECURE) &&
+ (++(invalid_entry->revalidation_cnt) > MAX_REVALIDATION_CNT)) {
+ VERBOSE_MSG(qry, "<= continuous revalidation, fails\n");
+ kr_request_set_extended_error(req, KNOT_EDNS_EDE_OTHER,
+ "4T4L: continuous revalidation");
+ qry->flags.DNSSEC_BOGUS = true;
+ return KR_STATE_FAIL;
+ }
+
+ const knot_rrset_t *rr = invalid_entry->rr;
+ if (kr_rank_test(invalid_entry->rank, KR_RANK_MISMATCH)) {
+ const knot_dname_t *signer_name = knot_rrsig_signer_name(rr->rrs.rdata);
+ if (knot_dname_in_bailiwick(signer_name, qry->zone_cut.name) > 0) {
+ qry->zone_cut.name = knot_dname_copy(signer_name, &req->pool);
+ qry->flags.AWAIT_CUT = true;
+ } else if (!knot_dname_is_equal(signer_name, qry->zone_cut.name)) {
+ if (qry->zone_cut.parent) {
+ memcpy(&qry->zone_cut, qry->zone_cut.parent, sizeof(qry->zone_cut));
+ } else {
+ qry->flags.AWAIT_CUT = true;
+ }
+ qry->zone_cut.name = knot_dname_copy(signer_name, &req->pool);
+ }
+ VERBOSE_MSG(qry, ">< cut changed (new signer), needs revalidation\n");
+ ret = KR_STATE_YIELD;
+ } else if (kr_rank_test(invalid_entry->rank, KR_RANK_MISSING)) {
+ ret = rrsig_not_found(ctx, pkt, rr);
+ } else if (!kr_rank_test(invalid_entry->rank, KR_RANK_SECURE)) {
+ kr_request_set_extended_error(req, KNOT_EDNS_EDE_BOGUS, "NXJA");
+ qry->flags.DNSSEC_BOGUS = true;
+ ret = KR_STATE_FAIL;
+ }
+
+ return ret;
+}
+
+static bool check_empty_answer(kr_layer_t *ctx, knot_pkt_t *pkt)
+{
+ struct kr_request *req = ctx->req;
+ struct kr_query *qry = req->current_query;
+ ranked_rr_array_t *arr = &req->answ_selected;
+ size_t num_entries = 0;
+ for (size_t i = 0; i < arr->len; ++i) {
+ ranked_rr_array_entry_t *entry = arr->at[i];
+ const knot_rrset_t *rr = entry->rr;
+ if (rr->type == KNOT_RRTYPE_RRSIG && qry->stype != KNOT_RRTYPE_RRSIG) {
+ continue;
+ }
+ if (entry->qry_uid == qry->uid) {
+ ++num_entries;
+ }
+ }
+ const knot_pktsection_t *an = knot_pkt_section(pkt, KNOT_ANSWER);
+ return ((an->count != 0) && (num_entries == 0)) ? false : true;
+}
+
+static int unsigned_forward(kr_layer_t *ctx, knot_pkt_t *pkt)
+{
+ struct kr_request *req = ctx->req;
+ struct kr_query *qry = req->current_query;
+ const uint16_t qtype = knot_pkt_qtype(pkt);
+ const uint8_t pkt_rcode = knot_wire_get_rcode(pkt->wire);
+ bool nods = false;
+ bool ns_exist = true;
+ for (int i = 0; i < req->rplan.resolved.len; ++i) {
+ struct kr_query *q = req->rplan.resolved.at[i];
+ if (q->sclass == qry->sclass &&
+ q->stype == KNOT_RRTYPE_DS &&
+ knot_dname_is_equal(q->sname, qry->sname)) {
+ nods = true;
+ if (!(q->flags.DNSSEC_OPTOUT)) {
+ int ret = kr_dnssec_matches_name_and_type(&req->auth_selected, q->uid,
+ qry->sname, KNOT_RRTYPE_NS);
+ ns_exist = (ret == kr_ok());
+ }
+ }
+ }
+
+ if (nods && ns_exist && qtype == KNOT_RRTYPE_NS) {
+ qry->flags.DNSSEC_WANT = false;
+ qry->flags.DNSSEC_INSECURE = true;
+ if (qry->forward_flags.CNAME) {
+ if (kr_fails_assert(qry->cname_parent))
+ return KR_STATE_FAIL;
+ qry->cname_parent->flags.DNSSEC_WANT = false;
+ qry->cname_parent->flags.DNSSEC_INSECURE = true;
+ } else if (pkt_rcode == KNOT_RCODE_NOERROR && qry->parent != NULL) {
+ const knot_pktsection_t *sec = knot_pkt_section(pkt, KNOT_ANSWER);
+ const knot_rrset_t *rr = knot_pkt_rr(sec, 0);
+ if (rr->type == KNOT_RRTYPE_NS) {
+ qry->parent->zone_cut.name = knot_dname_copy(rr->owner, &req->pool);
+ qry->parent->flags.DNSSEC_WANT = false;
+ qry->parent->flags.DNSSEC_INSECURE = true;
+ }
+ }
+ while (qry->parent) {
+ qry = qry->parent;
+ qry->flags.DNSSEC_WANT = false;
+ qry->flags.DNSSEC_INSECURE = true;
+ if (qry->forward_flags.CNAME) {
+ if (kr_fails_assert(qry->cname_parent))
+ return KR_STATE_FAIL;
+ qry->cname_parent->flags.DNSSEC_WANT = false;
+ qry->cname_parent->flags.DNSSEC_INSECURE = true;
+ }
+ }
+ return KR_STATE_DONE;
+ }
+
+ if (ctx->state == KR_STATE_YIELD) {
+ return KR_STATE_DONE;
+ }
+
+ if (!nods && qtype != KNOT_RRTYPE_DS) {
+ struct kr_rplan *rplan = &req->rplan;
+ struct kr_query *next = kr_rplan_push(rplan, qry, qry->sname, qry->sclass, KNOT_RRTYPE_DS);
+ if (!next) {
+ return KR_STATE_FAIL;
+ }
+ kr_zonecut_set(&next->zone_cut, qry->zone_cut.name);
+ kr_zonecut_copy_trust(&next->zone_cut, &qry->zone_cut);
+ next->flags.DNSSEC_WANT = true;
+ }
+
+ return KR_STATE_YIELD;
+}
+
+static int check_signer(kr_layer_t *ctx, knot_pkt_t *pkt)
+{
+ struct kr_request *req = ctx->req;
+ struct kr_query *qry = req->current_query;
+ 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(req);
+ if (ta_name && (!signer || !knot_dname_is_equal(ta_name, signer))) {
+ /* check all newly added RRSIGs */
+ if (!signer) {
+ if (qry->flags.FORWARD) {
+ return unsigned_forward(ctx, pkt);
+ }
+ /* Not a DNSSEC-signed response. */
+ if (ctx->state == KR_STATE_YIELD) {
+ /* Already yielded for revalidation.
+ * It means that trust chain is OK and
+ * transition to INSECURE hasn't occurred.
+ * Let the validation logic ask about RRSIG. */
+ return KR_STATE_DONE;
+ }
+ /* Ask parent for DS
+ * to prove transition to INSECURE. */
+ const uint16_t qtype = knot_pkt_qtype(pkt);
+ const knot_dname_t *qname = knot_pkt_qname(pkt);
+ if (qtype == KNOT_RRTYPE_NS &&
+ knot_dname_in_bailiwick(qname, qry->zone_cut.name) > 0) {
+ /* Server is authoritative
+ * for both parent and child,
+ * and child zone is not signed. */
+ qry->zone_cut.name = knot_dname_copy(qname, &req->pool);
+ }
+ } else if (knot_dname_in_bailiwick(signer, qry->zone_cut.name) > 0) {
+ if (!(qry->flags.FORWARD)) {
+ /* Key signer is below current cut, advance and refetch keys. */
+ qry->zone_cut.name = knot_dname_copy(signer, &req->pool);
+ } else {
+ /* Check if DS does not exist. */
+ struct kr_query *q = kr_rplan_find_resolved(&req->rplan, NULL,
+ signer, qry->sclass, KNOT_RRTYPE_DS);
+ if (q && q->flags.DNSSEC_NODS) {
+ qry->flags.DNSSEC_WANT = false;
+ qry->flags.DNSSEC_INSECURE = true;
+ if (qry->parent) {
+ qry->parent->flags.DNSSEC_WANT = false;
+ qry->parent->flags.DNSSEC_INSECURE = true;
+ }
+ } else if (qry->stype != KNOT_RRTYPE_DS) {
+ struct kr_rplan *rplan = &req->rplan;
+ struct kr_query *next = kr_rplan_push(rplan, qry, qry->sname,
+ qry->sclass, KNOT_RRTYPE_DS);
+ if (!next) {
+ return KR_STATE_FAIL;
+ }
+ kr_zonecut_set(&next->zone_cut, qry->zone_cut.name);
+ kr_zonecut_copy_trust(&next->zone_cut, &qry->zone_cut);
+ next->flags.DNSSEC_WANT = true;
+ }
+ }
+ } 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.AWAIT_CUT = true;
+ }
+ qry->zone_cut.name = knot_dname_copy(signer, &req->pool);
+ }
+
+ /* zone cut matches, but DS/DNSKEY doesn't => refetch. */
+ VERBOSE_MSG(qry, ">< cut changed, needs revalidation\n");
+ if ((qry->flags.FORWARD) && qry->stype != KNOT_RRTYPE_DS) {
+ struct kr_rplan *rplan = &req->rplan;
+ struct kr_query *next = kr_rplan_push(rplan, qry, signer,
+ qry->sclass, KNOT_RRTYPE_DS);
+ if (!next) {
+ return KR_STATE_FAIL;
+ }
+ kr_zonecut_set(&next->zone_cut, qry->zone_cut.name);
+ kr_zonecut_copy_trust(&next->zone_cut, &qry->zone_cut);
+ next->flags.DNSSEC_WANT = true;
+ return KR_STATE_YIELD;
+ }
+ if (!(qry->flags.FORWARD)) {
+ return KR_STATE_YIELD;
+ }
+ }
+ return KR_STATE_DONE;
+}
+
+/** Change ranks of RRs from this single iteration:
+ * _INITIAL or _TRY or _MISSING -> rank_to_set. Or any rank, if any_rank == true.
+ *
+ * Optionally do this only in a `bailiwick` (if not NULL).
+ * Iterator shouldn't have selected such records, but we check to be sure. */
+static void rank_records(struct kr_query *qry, bool any_rank, enum kr_rank rank_to_set,
+ const knot_dname_t *bailiwick)
+{
+ struct kr_request *req = qry->request;
+ ranked_rr_array_t *ptrs[2] = { &req->answ_selected, &req->auth_selected };
+ for (size_t i = 0; i < 2; ++i) {
+ ranked_rr_array_t *arr = ptrs[i];
+ for (size_t j = 0; j < arr->len; ++j) {
+ ranked_rr_array_entry_t *entry = arr->at[j];
+ if (entry->qry_uid != qry->uid) {
+ continue;
+ }
+ if (bailiwick && knot_dname_in_bailiwick(entry->rr->owner,
+ bailiwick) < 0) {
+ continue;
+ }
+ if (any_rank
+ || kr_rank_test(entry->rank, KR_RANK_INITIAL)
+ || kr_rank_test(entry->rank, KR_RANK_TRY)
+ || kr_rank_test(entry->rank, KR_RANK_MISSING)) {
+ kr_rank_set(&entry->rank, rank_to_set);
+ }
+ }
+ }
+}
+
+static void check_wildcard(kr_layer_t *ctx)
+{
+ struct kr_request *req = ctx->req;
+ struct kr_query *qry = req->current_query;
+ ranked_rr_array_t *ptrs[2] = { &req->answ_selected, &req->auth_selected };
+
+ for (int i = 0; i < 2; ++i) {
+ ranked_rr_array_t *arr = ptrs[i];
+ for (ssize_t j = 0; j < arr->len; ++j) {
+ ranked_rr_array_entry_t *entry = arr->at[j];
+ const knot_rrset_t *rrsigs = entry->rr;
+
+ if (qry->uid != entry->qry_uid) {
+ continue;
+ }
+
+ if (rrsigs->type != KNOT_RRTYPE_RRSIG) {
+ continue;
+ }
+
+ int owner_labels = knot_dname_labels(rrsigs->owner, NULL);
+
+ knot_rdata_t *rdata_k = rrsigs->rrs.rdata;
+ for (int k = 0; k < rrsigs->rrs.count;
+ ++k, rdata_k = knot_rdataset_next(rdata_k)) {
+ if (knot_rrsig_labels(rdata_k) != owner_labels) {
+ qry->flags.DNSSEC_WEXPAND = true;
+ }
+ }
+ }
+ }
+}
+
+/** Just for wildcard_adjust_to_wire() */
+static bool rr_is_for_wildcard(const ranked_rr_array_entry_t *entry)
+{
+ switch (kr_rrset_type_maysig(entry->rr)) {
+ case KNOT_RRTYPE_NSEC:
+ case KNOT_RRTYPE_NSEC3:
+ return true;
+ default:
+ return false;
+ }
+}
+/** In case of wildcard expansion, mark required authority RRs by to_wire. */
+static int wildcard_adjust_to_wire(struct kr_request *req, const struct kr_query *qry)
+{
+ if (!qry->parent && qry->flags.DNSSEC_WEXPAND) {
+ return kr_ranked_rrarray_set_wire(&req->auth_selected, true,
+ qry->uid, true, &rr_is_for_wildcard);
+ }
+ return kr_ok();
+}
+
+static int validate(kr_layer_t *ctx, knot_pkt_t *pkt)
+{
+ int ret = 0;
+ struct kr_request *req = ctx->req;
+ struct kr_query *qry = req->current_query;
+
+ /* Ignore faulty or unprocessed responses. */
+ if (ctx->state & (KR_STATE_FAIL|KR_STATE_CONSUME)) {
+ return ctx->state;
+ }
+
+ /* Pass-through if user doesn't want secure answer or stub. */
+ if (qry->flags.STUB) {
+ rank_records(qry, false, KR_RANK_OMIT, NULL);
+ return ctx->state;
+ }
+ uint8_t pkt_rcode = knot_wire_get_rcode(pkt->wire);
+ if ((qry->flags.FORWARD) &&
+ pkt_rcode != KNOT_RCODE_NOERROR &&
+ pkt_rcode != KNOT_RCODE_NXDOMAIN) {
+ do {
+ qry->flags.DNSSEC_BOGUS = true;
+ if (qry->cname_parent) {
+ qry->cname_parent->flags.DNSSEC_BOGUS = true;
+ }
+ qry = qry->parent;
+ } while (qry);
+ ctx->state = KR_STATE_DONE;
+ return ctx->state;
+ }
+
+ if (!(qry->flags.DNSSEC_WANT)) {
+ const bool is_insec = qry->flags.CACHED && qry->flags.DNSSEC_INSECURE;
+ if ((qry->flags.DNSSEC_INSECURE)) {
+ rank_records(qry, true, KR_RANK_INSECURE, qry->zone_cut.name);
+ }
+ if (is_insec && qry->parent != NULL) {
+ /* We have got insecure answer from cache.
+ * Mark parent(s) as insecure. */
+ mark_insecure_parents(qry);
+ VERBOSE_MSG(qry, "<= cached insecure response, going insecure\n");
+ ctx->state = KR_STATE_DONE;
+ } else if (ctx->state == KR_STATE_YIELD) {
+ /* Transition to insecure state
+ occurred during revalidation.
+ if state remains YIELD, answer will not be cached.
+ Let cache layers to work. */
+ ctx->state = KR_STATE_DONE;
+ }
+ return ctx->state;
+ }
+
+ /* Pass-through if CD bit is set. */
+ if (knot_wire_get_cd(req->qsource.packet->wire)) {
+ check_wildcard(ctx);
+ wildcard_adjust_to_wire(req, qry);
+ rank_records(qry, false, KR_RANK_OMIT, NULL);
+ 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.CACHED) && !knot_pkt_has_dnssec(pkt) && !use_signatures) {
+ VERBOSE_MSG(qry, "<= got insecure response\n");
+ kr_request_set_extended_error(req, KNOT_EDNS_EDE_BOGUS, "MISQ");
+ qry->flags.DNSSEC_BOGUS = true;
+ return KR_STATE_FAIL;
+ }
+
+ /* Check if this is a DNSKEY answer, check trust chain and store. */
+ uint16_t qtype = knot_pkt_qtype(pkt);
+ bool has_nsec3 = pkt_has_type(pkt, KNOT_RRTYPE_NSEC3);
+ const knot_pktsection_t *an = knot_pkt_section(pkt, KNOT_ANSWER);
+ const bool referral = (an->count == 0 && !knot_wire_get_aa(pkt->wire));
+
+ if (!(qry->flags.CACHED) && knot_wire_get_aa(pkt->wire)) {
+ /* Check if answer if not empty,
+ * but iterator has not selected any records. */
+ if (!check_empty_answer(ctx, pkt)) {
+ VERBOSE_MSG(qry, "<= no useful RR in authoritative answer\n");
+ kr_request_set_extended_error(req, KNOT_EDNS_EDE_BOGUS, "MJX6");
+ qry->flags.DNSSEC_BOGUS = true;
+ return KR_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.
+ */
+ ret = check_signer(ctx, pkt);
+ if (ret != KR_STATE_DONE) {
+ return ret;
+ }
+ if (qry->flags.FORWARD && qry->flags.DNSSEC_INSECURE) {
+ return KR_STATE_DONE;
+ }
+ }
+
+ if (knot_wire_get_aa(pkt->wire) && qtype == KNOT_RRTYPE_DNSKEY) {
+ const knot_rrset_t *ds = qry->zone_cut.trust_anchor;
+ if (ds && !kr_ds_algo_support(ds)) {
+ VERBOSE_MSG(qry, ">< all DS entries use unsupported algorithm pairs, going insecure\n");
+ /* ^ the message is a bit imprecise to avoid being too verbose */
+ kr_request_set_extended_error(req, KNOT_EDNS_EDE_OTHER, "LSLC: unsupported digest/key");
+ qry->flags.DNSSEC_WANT = false;
+ qry->flags.DNSSEC_INSECURE = true;
+ rank_records(qry, true, KR_RANK_INSECURE, qry->zone_cut.name);
+ mark_insecure_parents(qry);
+ return KR_STATE_DONE;
+ }
+
+ ret = validate_keyset(req, pkt, has_nsec3);
+ if (ret == kr_error(EAGAIN)) {
+ VERBOSE_MSG(qry, ">< cut changed, needs revalidation\n");
+ return KR_STATE_YIELD;
+ } else if (ret != 0) {
+ VERBOSE_MSG(qry, "<= bad keys, broken trust chain\n");
+ /* EDE code already set in validate_keyset() */
+ qry->flags.DNSSEC_BOGUS = true;
+ return KR_STATE_FAIL;
+ }
+ }
+
+ /* Validate all records, fail as bogus if it doesn't match.
+ * Do not revalidate data from cache, as it's already trusted.
+ * TTLs of RRsets may get lowered. */
+ if (!(qry->flags.CACHED)) {
+ ret = validate_records(req, pkt, req->rplan.pool, has_nsec3);
+ if (ret == KNOT_EDOWNGRADED) {
+ return KR_STATE_DONE;
+ } else if (ret != 0) {
+ /* something exceptional - no DNS key, empty pointers etc
+ * normally it shouldn't happen */
+ VERBOSE_MSG(qry, "<= couldn't validate RRSIGs\n");
+ kr_request_set_extended_error(req, KNOT_EDNS_EDE_OTHER,
+ "O4TP: couldn't validate RRSIGs");
+ qry->flags.DNSSEC_BOGUS = true;
+ return KR_STATE_FAIL;
+ }
+ /* check validation state and spawn subrequests */
+ if (!req->answ_validated) {
+ ret = check_validation_result(ctx, pkt, &req->answ_selected);
+ if (ret != KR_STATE_DONE) {
+ return ret;
+ }
+ }
+ if (!req->auth_validated) {
+ ret = check_validation_result(ctx, pkt, &req->auth_selected);
+ if (ret != KR_STATE_DONE) {
+ return ret;
+ }
+ }
+ }
+
+ /* Validate non-existence proof if not positive answer.
+ * In case of CNAME, iterator scheduled a sibling query for the target,
+ * so we just drop the negative piece of information and don't try to prove it.
+ * TODO: not ideal; with aggressive cache we'll at least avoid the extra packet. */
+ if (!qry->flags.CACHED && pkt_rcode == KNOT_RCODE_NXDOMAIN && !qry->flags.CNAME) {
+ /* @todo If knot_pkt_qname(pkt) is used instead of qry->sname then the tests crash. */
+ if (!has_nsec3) {
+ ret = kr_nsec_negative(&req->auth_selected, qry->uid,
+ qry->sname, KNOT_RRTYPE_NULL);
+ if (ret >= 0) {
+ if (ret & PKT_NXDOMAIN) {
+ ret = kr_ok();
+ } else {
+ ret = kr_error(ENOENT); // probably proved NODATA
+ }
+ }
+ } else {
+ ret = kr_nsec3_name_error_response_check(pkt, KNOT_AUTHORITY, qry->sname);
+ }
+ if (has_nsec3 && (ret == kr_error(KNOT_ERANGE))) {
+ /* NXDOMAIN proof is OK,
+ * but NSEC3 that covers next closer name
+ * (or wildcard at next closer name) has opt-out flag.
+ * RFC5155 9.2; AD flag can not be set */
+ qry->flags.DNSSEC_OPTOUT = true;
+ VERBOSE_MSG(qry, "<= can't prove NXDOMAIN due to optout, going insecure\n");
+ } else if (ret != 0) {
+ VERBOSE_MSG(qry, "<= bad NXDOMAIN proof\n");
+ kr_request_set_extended_error(req, KNOT_EDNS_EDE_NSEC_MISS, "3WKM");
+ qry->flags.DNSSEC_BOGUS = true;
+ return KR_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
+ * CNAME: same as the NXDOMAIN case above */
+ if (!qry->flags.CACHED && pkt_rcode == KNOT_RCODE_NOERROR && !qry->flags.CNAME) {
+ bool no_data = (an->count == 0 && knot_wire_get_aa(pkt->wire));
+ if (no_data) {
+ /* @todo
+ * ? quick mechanism to determine which check to preform first
+ * ? merge the functionality together to share code/resources
+ */
+ if (!has_nsec3) {
+ ret = kr_nsec_negative(&req->auth_selected, qry->uid,
+ knot_pkt_qname(pkt), knot_pkt_qtype(pkt));
+ if (ret >= 0) {
+ if (ret == PKT_NODATA) {
+ ret = kr_ok();
+ } else {
+ ret = kr_error(ENOENT); // suspicious
+ }
+ }
+ } 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(KNOT_ERANGE))) {
+ VERBOSE_MSG(qry, "<= can't prove NODATA due to optout, going insecure\n");
+ qry->flags.DNSSEC_OPTOUT = true;
+ /* Could not return from here,
+ * we must continue, validate NSEC\NSEC3 and
+ * call update_parent_keys() to mark
+ * parent queries as insecure */
+ } else {
+ VERBOSE_MSG(qry, "<= bad NODATA proof\n");
+ kr_request_set_extended_error(req, KNOT_EDNS_EDE_NSEC_MISS, "AHXI");
+ qry->flags.DNSSEC_BOGUS = true;
+ return KR_STATE_FAIL;
+ }
+ }
+ }
+ }
+
+ wildcard_adjust_to_wire(req, qry);
+
+ /* Check and update current delegation point security status. */
+ ret = update_delegation(req, qry, pkt, has_nsec3);
+ if (ret == DNSSEC_NOT_FOUND && qry->stype != KNOT_RRTYPE_DS) {
+ if (ctx->state == KR_STATE_YIELD) {
+ VERBOSE_MSG(qry, "<= can't validate referral\n");
+ kr_request_set_extended_error(req, KNOT_EDNS_EDE_BOGUS, "XLE4");
+ qry->flags.DNSSEC_BOGUS = true;
+ return KR_STATE_FAIL;
+ } else {
+ /* Check the trust chain and query DS\DNSKEY if needed. */
+ VERBOSE_MSG(qry, "<= DS\\NSEC was not found, querying for DS\n");
+ return KR_STATE_YIELD;
+ }
+ } else if (ret != 0) {
+ return KR_STATE_FAIL;
+ } else if (pkt_rcode == KNOT_RCODE_NOERROR &&
+ referral &&
+ ((!qry->flags.DNSSEC_WANT && qry->flags.DNSSEC_INSECURE) ||
+ (qry->flags.DNSSEC_NODS))) {
+ /* referral with proven DS non-existence */
+ qtype = KNOT_RRTYPE_DS;
+ }
+ /* Update parent query zone cut */
+ if (qry->parent) {
+ if (update_parent_keys(req, qtype) != 0) {
+ return KR_STATE_FAIL;
+ }
+ }
+
+ if (qry->flags.FORWARD && qry->parent) {
+ if (pkt_rcode == KNOT_RCODE_NXDOMAIN) {
+ qry->parent->forward_flags.NO_MINIMIZE = true;
+ }
+ }
+ VERBOSE_MSG(qry, "<= answer valid, OK\n");
+ return KR_STATE_DONE;
+}
+
+/** Hide RRsets which did not validate from clients. */
+static int hide_bogus(kr_layer_t *ctx) {
+ if (knot_wire_get_cd(ctx->req->qsource.packet->wire)) {
+ return ctx->state;
+ }
+ /* We don't want to send bogus answers to clients, not even in SERVFAIL
+ * answers, but we cannot drop whole sections. If a CNAME chain
+ * SERVFAILs somewhere, the steps that were OK should be put into
+ * answer.
+ *
+ * There is one specific issue: currently we follow CNAME *before*
+ * we validate it, because... iterator comes before validator.
+ * Therefore some rrsets might be added into req->*_selected before
+ * we detected failure in validator.
+ * TODO: better approach, probably during work on parallel queries.
+ */
+ const ranked_rr_array_t *sel[] = kr_request_selected(ctx->req);
+ for (knot_section_t sect = KNOT_ANSWER; sect <= KNOT_ADDITIONAL; ++sect) {
+ for (size_t i = 0; i < sel[sect]->len; ++i) {
+ ranked_rr_array_entry_t *e = sel[sect]->at[i];
+ e->to_wire = e->to_wire
+ && !kr_rank_test(e->rank, KR_RANK_INDET)
+ && !kr_rank_test(e->rank, KR_RANK_BOGUS)
+ && !kr_rank_test(e->rank, KR_RANK_MISMATCH)
+ && !kr_rank_test(e->rank, KR_RANK_MISSING);
+ }
+ }
+ return ctx->state;
+}
+
+static int validate_wrapper(kr_layer_t *ctx, knot_pkt_t *pkt) {
+ // Wrapper for now.
+ int ret = validate(ctx, pkt);
+ struct kr_request *req = ctx->req;
+ struct kr_query *qry = req->current_query;
+ if (ret & KR_STATE_FAIL && qry->flags.DNSSEC_BOGUS)
+ qry->server_selection.error(qry, req->upstream.transport, KR_SELECTION_DNSSEC_ERROR);
+ if (ret & KR_STATE_DONE && !qry->flags.DNSSEC_BOGUS) {
+ /* Don't report extended DNS errors related to validation
+ * when it managed to succeed (e.g. by trying different auth). */
+ switch (req->extended_error.info_code) {
+ case KNOT_EDNS_EDE_BOGUS:
+ case KNOT_EDNS_EDE_NSEC_MISS:
+ case KNOT_EDNS_EDE_RRSIG_MISS:
+ case KNOT_EDNS_EDE_SIG_EXPIRED:
+ case KNOT_EDNS_EDE_SIG_NOTYET:
+ kr_request_set_extended_error(req, KNOT_EDNS_EDE_NONE, NULL);
+ break;
+ case KNOT_EDNS_EDE_DNSKEY_MISS:
+ case KNOT_EDNS_EDE_DNSKEY_BIT:
+ kr_assert(false); /* These EDE codes aren't used. */
+ break;
+ default: break; /* Remaining codes don't indicate hard DNSSEC failure. */
+ }
+ }
+ return ret;
+}
+
+
+/** Module implementation. */
+int validate_init(struct kr_module *self)
+{
+ static const kr_layer_api_t layer = {
+ .consume = &validate_wrapper,
+ .answer_finalize = &hide_bogus,
+ };
+ self->layer = &layer;
+ return kr_ok();
+}
+
+KR_MODULE_EXPORT(validate) /* useless for builtin module, but let's be consistent */
+
+#undef VERBOSE_MSG