diff options
Diffstat (limited to '')
| -rw-r--r-- | lib/layer.h | 107 | ||||
| -rw-r--r-- | lib/layer/cache.c | 31 | ||||
| -rw-r--r-- | lib/layer/iterate.c | 1135 | ||||
| -rw-r--r-- | lib/layer/iterate.h | 36 | ||||
| -rw-r--r-- | lib/layer/validate.c | 1133 |
5 files changed, 2442 insertions, 0 deletions
diff --git a/lib/layer.h b/lib/layer.h new file mode 100644 index 0000000..0909cb7 --- /dev/null +++ b/lib/layer.h @@ -0,0 +1,107 @@ +/* Copyright (C) 2014-2017 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz> + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. + */ + +#pragma once + +#include "lib/defines.h" +#include "lib/utils.h" + +#ifdef NOVERBOSELOG + #define QRVERBOSE(query, cls, ...) +#else + /** Print a debug message related to resolution. + * \param _query associated kr_query, may be NULL + * \param _cls identifying string, typically of length exactly four (padded) + * \param ... printf-compatible list of parameters + */ + #define QRVERBOSE(_query, _cls, ...) do { \ + const struct kr_query *_qry = (_query); \ + if (kr_log_trace_enabled(_qry)) { \ + kr_log_trace(_qry, (_cls), __VA_ARGS__); \ + } else if (VERBOSE_STATUS) { \ + kr_log_qverbose_impl(_qry, (_cls), __VA_ARGS__); \ + } \ + } while (false) +#endif + +/** Layer processing states. Only one value at a time (but see TODO). + * + * Each state represents the state machine transition, + * and determines readiness for the next action. + * See struct kr_layer_api for the actions. + * + * TODO: the cookie module sometimes sets (_FAIL | _DONE) on purpose (!) + */ +enum kr_layer_state { + KR_STATE_CONSUME = 1 << 0, /*!< Consume data. */ + KR_STATE_PRODUCE = 1 << 1, /*!< Produce data. */ + KR_STATE_DONE = 1 << 2, /*!< Finished successfully. */ + KR_STATE_FAIL = 1 << 3, /*!< Error. */ + KR_STATE_YIELD = 1 << 4, /*!< Paused, waiting for a sub-query. */ +}; + +/* Forward declarations. */ +struct kr_layer_api; + +/** Packet processing context. */ +typedef struct kr_layer { + int state; /*!< The current state; bitmap of enum kr_layer_state. */ + struct kr_request *req; /*!< The corresponding request. */ + const struct kr_layer_api *api; +} kr_layer_t; + +/** Packet processing module API. All functions return the new kr_layer_state. */ +struct kr_layer_api { + /** Start of processing the DNS request. */ + int (*begin)(kr_layer_t *ctx); + + int (*reset)(kr_layer_t *ctx); + + /** Paired to begin, called both on successes and failures. */ + int (*finish)(kr_layer_t *ctx); + + /** Processing an answer from upstream or the answer to the request. */ + int (*consume)(kr_layer_t *ctx, knot_pkt_t *pkt); + + /** Produce either an answer to the request or a query for upstream (or fail). */ + int (*produce)(kr_layer_t *ctx, knot_pkt_t *pkt); + + /** Finalises the outbound query packet with the knowledge of the IP addresses. + * The checkout layer doesn't persist the state, so canceled subrequests + * don't affect the resolution or rest of the processing. */ + int (*checkout)(kr_layer_t *ctx, knot_pkt_t *packet, struct sockaddr *dst, int type); + + /** Finalises the answer. + * Last chance to affect what will get into the answer, including EDNS.*/ + int (*answer_finalize)(kr_layer_t *ctx); + + /** The module can store anything in here. */ + void *data; + + /** Internal to ./daemon/ffimodule.c. */ + int cb_slots[]; +}; + +typedef struct kr_layer_api kr_layer_api_t; + +/** Pickled layer state (api, input, state). */ +struct kr_layer_pickle { + struct kr_layer_pickle *next; + const struct kr_layer_api *api; + knot_pkt_t *pkt; + unsigned state; +}; + diff --git a/lib/layer/cache.c b/lib/layer/cache.c new file mode 100644 index 0000000..c7bbc1a --- /dev/null +++ b/lib/layer/cache.c @@ -0,0 +1,31 @@ +/* Copyright (C) 2017 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz> + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. + */ + +#include "lib/module.h" +#include "lib/cache/api.h" + +/** Module implementation. */ +const kr_layer_api_t *cache_layer(struct kr_module *module) +{ + static const kr_layer_api_t _layer = { + .produce = &cache_peek, + .consume = &cache_stash, + }; + + return &_layer; +} + +KR_MODULE_EXPORT(cache) diff --git a/lib/layer/iterate.c b/lib/layer/iterate.c new file mode 100644 index 0000000..cf57cc5 --- /dev/null +++ b/lib/layer/iterate.c @@ -0,0 +1,1135 @@ +/* Copyright (C) 2014-2017 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz> + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. + */ + +/** @file iterate.c + * + * This builtin module is mainly active in the consume phase. + * Primary responsibilities: + * - Classify the packet as auth/nonauth and change its AA flag accordingly. + * - Pick interesting RRs to kr_request::answ_selected and ::auth_selected, + * NEW: and classify their rank, except for validation status. + * - Update kr_query::zone_cut (in case of referral). + * - Interpret CNAMEs. + * - Prepare the followup query - either inline or as another kr_query + * (CNAME jumps create a new "sibling" query). + */ + +#include <sys/time.h> +#include <assert.h> +#include <arpa/inet.h> + +#include <contrib/cleanup.h> +#include <libknot/descriptor.h> +#include <libknot/rrtype/rdname.h> +#include <libknot/rrtype/rrsig.h> + +#include "lib/layer/iterate.h" +#include "lib/resolve.h" +#include "lib/rplan.h" +#include "lib/defines.h" +#include "lib/nsrep.h" +#include "lib/module.h" +#include "lib/dnssec/ta.h" + +#define VERBOSE_MSG(...) QRVERBOSE(req->current_query, "iter", __VA_ARGS__) +#define QVERBOSE_MSG(qry, ...) QRVERBOSE(qry, "iter", __VA_ARGS__) + +/* Iterator often walks through packet section, this is an abstraction. */ +typedef int (*rr_callback_t)(const knot_rrset_t *, unsigned, struct kr_request *); + +/** Return minimized QNAME/QTYPE for current zone cut. */ +static const knot_dname_t *minimized_qname(struct kr_query *query, uint16_t *qtype) +{ + /* Minimization disabled. */ + const knot_dname_t *qname = query->sname; + if (qname[0] == '\0' || query->flags.NO_MINIMIZE || query->flags.STUB) { + return qname; + } + + /* Minimize name to contain current zone cut + 1 label. */ + int cut_labels = knot_dname_labels(query->zone_cut.name, NULL); + int qname_labels = knot_dname_labels(qname, NULL); + while(qname[0] && qname_labels > cut_labels + 1) { + qname = knot_wire_next_label(qname, NULL); + qname_labels -= 1; + } + + /* Hide QTYPE if minimized. */ + if (qname != query->sname) { + *qtype = KNOT_RRTYPE_NS; + } + + return qname; +} + +/** Answer is paired to query. */ +static bool is_paired_to_query(const knot_pkt_t *answer, struct kr_query *query) +{ + uint16_t qtype = query->stype; + const knot_dname_t *qname = minimized_qname(query, &qtype); + + return query->id == knot_wire_get_id(answer->wire) && + knot_wire_get_qdcount(answer->wire) > 0 && + query->sclass == knot_pkt_qclass(answer) && + qtype == knot_pkt_qtype(answer) && + knot_dname_is_equal(qname, knot_pkt_qname(answer)); +} + +/** Relaxed rule for AA, either AA=1 or SOA matching zone cut is required. */ +static bool is_authoritative(const knot_pkt_t *answer, struct kr_query *query) +{ + if (knot_wire_get_aa(answer->wire)) { + return true; + } + + const knot_pktsection_t *ns = knot_pkt_section(answer, KNOT_AUTHORITY); + for (unsigned i = 0; i < ns->count; ++i) { + const knot_rrset_t *rr = knot_pkt_rr(ns, i); + if (rr->type == KNOT_RRTYPE_SOA + && knot_dname_in_bailiwick(rr->owner, query->zone_cut.name) >= 0) { + return true; + } + } + +#ifndef STRICT_MODE + /* Last resort to work around broken auths, if the zone cut is at/parent of the QNAME. */ + if (knot_dname_is_equal(query->zone_cut.name, knot_pkt_qname(answer))) { + return true; + } +#endif + + /* Some authoritative servers are hopelessly broken, allow lame answers in permissive mode. */ + if (query->flags.PERMISSIVE) { + return true; + } + + return false; +} + +int kr_response_classify(const knot_pkt_t *pkt) +{ + const knot_pktsection_t *an = knot_pkt_section(pkt, KNOT_ANSWER); + switch (knot_wire_get_rcode(pkt->wire)) { + case KNOT_RCODE_NOERROR: + return (an->count == 0) ? PKT_NODATA : PKT_NOERROR; + case KNOT_RCODE_NXDOMAIN: + return PKT_NXDOMAIN; + case KNOT_RCODE_REFUSED: + return PKT_REFUSED; + default: + return PKT_ERROR; + } +} + +/** @internal Filter ANY or loopback addresses. */ +static bool is_valid_addr(const uint8_t *addr, size_t len) +{ + if (len == sizeof(struct in_addr)) { + /* Filter ANY and 127.0.0.0/8 */ + uint32_t ip_host = ntohl(*(const uint32_t *)(addr)); + if (ip_host == 0 || (ip_host & 0xff000000) == 0x7f000000) { + return false; + } + } else if (len == sizeof(struct in6_addr)) { + struct in6_addr ip6_mask; + memset(&ip6_mask, 0, sizeof(ip6_mask)); + /* All except last byte are zeroed, last byte defines ANY/::1 */ + if (memcmp(addr, ip6_mask.s6_addr, sizeof(ip6_mask.s6_addr) - 1) == 0) { + return (addr[len - 1] > 1); + } + } + return true; +} + +/** @internal Update NS address from record \a rr. Return _FAIL on error. */ +static int update_nsaddr(const knot_rrset_t *rr, struct kr_query *query, int *glue_cnt) +{ + if (rr->type == KNOT_RRTYPE_A || rr->type == KNOT_RRTYPE_AAAA) { + const knot_rdata_t *rdata = rr->rrs.rdata; + const int a_len = rr->type == KNOT_RRTYPE_A + ? sizeof(struct in_addr) : sizeof(struct in6_addr); + if (a_len != rdata->len) { + QVERBOSE_MSG(query, "<= ignoring invalid glue, length %d != %d\n", + (int)rdata->len, a_len); + return KR_STATE_FAIL; + } + char name_str[KR_DNAME_STR_MAXLEN]; + char addr_str[INET6_ADDRSTRLEN]; + WITH_VERBOSE(query) { + const int af = (rr->type == KNOT_RRTYPE_A) ? AF_INET : AF_INET6; + knot_dname_to_str(name_str, rr->owner, sizeof(name_str)); + name_str[sizeof(name_str) - 1] = 0; + inet_ntop(af, rdata->data, addr_str, sizeof(addr_str)); + } + if (!(query->flags.ALLOW_LOCAL) && + !is_valid_addr(rdata->data, rdata->len)) { + QVERBOSE_MSG(query, "<= ignoring invalid glue for " + "'%s': '%s'\n", name_str, addr_str); + return KR_STATE_CONSUME; /* Ignore invalid addresses */ + } + int ret = kr_zonecut_add(&query->zone_cut, rr->owner, rdata->data, rdata->len); + if (ret != 0) { + return KR_STATE_FAIL; + } + + ++*glue_cnt; /* reduced verbosity */ + /* QVERBOSE_MSG(query, "<= using glue for " + "'%s': '%s'\n", name_str, addr_str); + */ + } + return KR_STATE_CONSUME; +} + +/** @internal From \a pkt, fetch glue records for name \a ns, and update the cut etc. + * + * \param glue_cnt the number of accepted addresses (to be incremented) + */ +static void fetch_glue(knot_pkt_t *pkt, const knot_dname_t *ns, bool in_bailiwick, + struct kr_request *req, const struct kr_query *qry, int *glue_cnt) +{ + ranked_rr_array_t *selected[] = kr_request_selected(req); + for (knot_section_t i = KNOT_ANSWER; i <= KNOT_ADDITIONAL; ++i) { + const knot_pktsection_t *sec = knot_pkt_section(pkt, i); + for (unsigned k = 0; k < sec->count; ++k) { + const knot_rrset_t *rr = knot_pkt_rr(sec, k); + if (!knot_dname_is_equal(ns, rr->owner)) { + continue; + } + if ((rr->type != KNOT_RRTYPE_A) && + (rr->type != KNOT_RRTYPE_AAAA)) { + continue; + } + + uint8_t rank = (in_bailiwick && i == KNOT_ANSWER) + ? (KR_RANK_INITIAL | KR_RANK_AUTH) : KR_RANK_OMIT; + (void) kr_ranked_rrarray_add(selected[i], rr, rank, + false, qry->uid, &req->pool); + + if ((rr->type == KNOT_RRTYPE_A) && + (req->ctx->options.NO_IPV4)) { + continue; + } + if ((rr->type == KNOT_RRTYPE_AAAA) && + (req->ctx->options.NO_IPV6)) { + continue; + } + (void) update_nsaddr(rr, req->current_query, glue_cnt); + } + } +} + +/** Attempt to find glue for given nameserver name (best effort). */ +static bool has_glue(knot_pkt_t *pkt, const knot_dname_t *ns) +{ + for (knot_section_t i = KNOT_ANSWER; i <= KNOT_ADDITIONAL; ++i) { + const knot_pktsection_t *sec = knot_pkt_section(pkt, i); + for (unsigned k = 0; k < sec->count; ++k) { + const knot_rrset_t *rr = knot_pkt_rr(sec, k); + if (knot_dname_is_equal(ns, rr->owner) && + (rr->type == KNOT_RRTYPE_A || rr->type == KNOT_RRTYPE_AAAA)) { + return true; + } + } + } + return false; +} + +/** @internal Update the cut with another NS(+glue) record. + * @param current_cut is cut name before this packet. + * @return _DONE if cut->name changes, _FAIL on error, and _CONSUME otherwise. */ +static int update_cut(knot_pkt_t *pkt, const knot_rrset_t *rr, + struct kr_request *req, const knot_dname_t *current_cut, + int *glue_cnt) +{ + struct kr_query *qry = req->current_query; + struct kr_zonecut *cut = &qry->zone_cut; + int state = KR_STATE_CONSUME; + + /* New authority MUST be at/below the authority of the current cut; + * also qname must be below new authority; + * otherwise it's a possible cache injection attempt. */ + const bool ok = knot_dname_in_bailiwick(rr->owner, current_cut) >= 0 + && knot_dname_in_bailiwick(qry->sname, rr->owner) >= 0; + if (!ok) { + VERBOSE_MSG("<= authority: ns outside bailiwick\n"); +#ifdef STRICT_MODE + return KR_STATE_FAIL; +#else + /* Workaround: ignore out-of-bailiwick NSs for authoritative answers, + * but fail for referrals. This is important to detect lame answers. */ + if (knot_pkt_section(pkt, KNOT_ANSWER)->count == 0) { + state = KR_STATE_FAIL; + } + return state; +#endif + } + + /* Update zone cut name */ + if (!knot_dname_is_equal(rr->owner, cut->name)) { + /* Remember parent cut and descend to new (keep keys and TA). */ + struct kr_zonecut *parent = mm_alloc(&req->pool, sizeof(*parent)); + if (parent) { + memcpy(parent, cut, sizeof(*parent)); + kr_zonecut_init(cut, rr->owner, &req->pool); + cut->key = parent->key; + cut->trust_anchor = parent->trust_anchor; + cut->parent = parent; + } else { + kr_zonecut_set(cut, rr->owner); + } + state = KR_STATE_DONE; + } + + /* Fetch glue for each NS */ + knot_rdata_t *rdata_i = rr->rrs.rdata; + for (unsigned i = 0; i < rr->rrs.count; + ++i, rdata_i = knot_rdataset_next(rdata_i)) { + const knot_dname_t *ns_name = knot_ns_name(rdata_i); + /* Glue is mandatory for NS below zone */ + if (knot_dname_in_bailiwick(ns_name, rr->owner) >= 0 + && !has_glue(pkt, ns_name)) { + const char *msg = + "<= authority: missing mandatory glue, skipping NS"; + WITH_VERBOSE(qry) { + auto_free char *ns_str = kr_dname_text(ns_name); + VERBOSE_MSG("%s %s\n", msg, ns_str); + } + continue; + } + int ret = kr_zonecut_add(cut, ns_name, NULL, 0); + assert(!ret); (void)ret; + + /* Choose when to use glue records. */ + const bool in_bailiwick = + knot_dname_in_bailiwick(ns_name, current_cut) >= 0; + bool do_fetch; + if (qry->flags.PERMISSIVE) { + do_fetch = true; + } else if (qry->flags.STRICT) { + /* Strict mode uses only mandatory glue. */ + do_fetch = knot_dname_in_bailiwick(ns_name, cut->name) >= 0; + } else { + /* Normal mode uses in-bailiwick glue. */ + do_fetch = in_bailiwick; + } + if (do_fetch) { + fetch_glue(pkt, ns_name, in_bailiwick, req, qry, glue_cnt); + } + } + + return state; +} + +/** Compute rank appropriate for RRs present in the packet. + * @param answer whether the RR is from answer or authority section + * @param is_nonauth: from referral or forwarding (etc.) */ +static uint8_t get_initial_rank(const knot_rrset_t *rr, const struct kr_query *qry, + const bool answer, const bool is_nonauth) +{ + /* For RRSIGs, ensure the KR_RANK_AUTH flag corresponds to the signed RR. */ + uint16_t type = kr_rrset_type_maysig(rr); + + if (qry->flags.CACHED) { + return rr->additional ? *(uint8_t *)rr->additional : KR_RANK_OMIT; + /* ^^ Current use case for "cached" RRs without rank: hints module. */ + } + if (answer || type == KNOT_RRTYPE_DS + || type == KNOT_RRTYPE_SOA /* needed for aggressive negative caching */ + || type == KNOT_RRTYPE_NSEC || type == KNOT_RRTYPE_NSEC3) { + /* We almost always want these validated, and it should be possible. */ + return KR_RANK_INITIAL | KR_RANK_AUTH; + } + /* Be aggressive: try to validate anything else (almost never extra latency). */ + return KR_RANK_TRY; + /* TODO: this classifier of authoritativity may not be perfect yet. */ +} + +static int pick_authority(knot_pkt_t *pkt, struct kr_request *req, bool to_wire) +{ + struct kr_query *qry = req->current_query; + const knot_pktsection_t *ns = knot_pkt_section(pkt, KNOT_AUTHORITY); + + const knot_dname_t *zonecut_name = qry->zone_cut.name; + bool referral = !knot_wire_get_aa(pkt->wire); + if (referral) { + /* zone cut already updated by process_authority() + * use parent zonecut name */ + zonecut_name = qry->zone_cut.parent ? qry->zone_cut.parent->name : qry->zone_cut.name; + to_wire = false; + } + + for (unsigned i = 0; i < ns->count; ++i) { + const knot_rrset_t *rr = knot_pkt_rr(ns, i); + if (rr->rclass != KNOT_CLASS_IN + || knot_dname_in_bailiwick(rr->owner, zonecut_name) < 0) { + continue; + } + uint8_t rank = get_initial_rank(rr, qry, false, + qry->flags.FORWARD || referral); + int ret = kr_ranked_rrarray_add(&req->auth_selected, rr, + rank, to_wire, qry->uid, &req->pool); + if (ret != kr_ok()) { + return ret; + } + } + + return kr_ok(); +} + +static int process_authority(knot_pkt_t *pkt, struct kr_request *req) +{ + struct kr_query *qry = req->current_query; + assert(!(qry->flags.STUB)); + + int result = KR_STATE_CONSUME; + if (qry->flags.FORWARD) { + return result; + } + + const knot_pktsection_t *ns = knot_pkt_section(pkt, KNOT_AUTHORITY); + const knot_pktsection_t *an = knot_pkt_section(pkt, KNOT_ANSWER); + +#ifdef STRICT_MODE + /* AA, terminate resolution chain. */ + if (knot_wire_get_aa(pkt->wire)) { + return KR_STATE_CONSUME; + } +#else + /* Work around servers sending back CNAME with different delegation and no AA. */ + if (an->count > 0 && ns->count > 0) { + const knot_rrset_t *rr = knot_pkt_rr(an, 0); + if (rr->type == KNOT_RRTYPE_CNAME) { + return KR_STATE_CONSUME; + } + /* Work around for these NSs which are authoritative both for + * parent and child and mixes data from both zones in single answer */ + if (knot_wire_get_aa(pkt->wire) && + (rr->type == qry->stype) && + (knot_dname_is_equal(rr->owner, qry->sname))) { + return KR_STATE_CONSUME; + } + } +#endif + /* Remember current bailiwick for NS processing. */ + const knot_dname_t *current_zone_cut = qry->zone_cut.name; + bool ns_record_exists = false; + int glue_cnt = 0; + /* Update zone cut information. */ + for (unsigned i = 0; i < ns->count; ++i) { + const knot_rrset_t *rr = knot_pkt_rr(ns, i); + if (rr->type == KNOT_RRTYPE_NS) { + ns_record_exists = true; + int state = update_cut(pkt, rr, req, current_zone_cut, &glue_cnt); + switch(state) { + case KR_STATE_DONE: result = state; break; + case KR_STATE_FAIL: return state; break; + default: /* continue */ break; + } + } else if (rr->type == KNOT_RRTYPE_SOA + && knot_dname_in_bailiwick(rr->owner, qry->zone_cut.name) > 0) { + /* SOA below cut in authority indicates different authority, + * but same NS set. */ + qry->zone_cut.name = knot_dname_copy(rr->owner, &req->pool); + } + } + + /* Nameserver is authoritative for both parent side and the child side of the + * delegation may respond with an NS record in the answer section, and still update + * the zone cut (e.g. what a.gtld-servers.net would respond for `com NS`) */ + if (!ns_record_exists && knot_wire_get_aa(pkt->wire)) { + for (unsigned i = 0; i < an->count; ++i) { + const knot_rrset_t *rr = knot_pkt_rr(an, i); + if (rr->type == KNOT_RRTYPE_NS + && knot_dname_in_bailiwick(rr->owner, qry->zone_cut.name) > 0) { + /* NS below cut in authority indicates different authority, + * but same NS set. */ + qry->zone_cut.name = knot_dname_copy(rr->owner, &req->pool); + } + } + } + + if (glue_cnt) { + VERBOSE_MSG("<= loaded %d glue addresses\n", glue_cnt); + } + + + if ((qry->flags.DNSSEC_WANT) && (result == KR_STATE_CONSUME)) { + if (knot_wire_get_aa(pkt->wire) == 0 && + knot_wire_get_ancount(pkt->wire) == 0 && + ns_record_exists) { + /* Unhelpful referral + Prevent from validating as an authoritative answer */ + result = KR_STATE_DONE; + } + } + + /* CONSUME => Unhelpful referral. + * DONE => Zone cut updated. */ + return result; +} + +static void finalize_answer(knot_pkt_t *pkt, struct kr_query *qry, struct kr_request *req) +{ + /* Finalize header */ + knot_pkt_t *answer = req->answer; + knot_wire_set_rcode(answer->wire, knot_wire_get_rcode(pkt->wire)); +} + +static int unroll_cname(knot_pkt_t *pkt, struct kr_request *req, bool referral, const knot_dname_t **cname_ret) +{ + struct kr_query *query = req->current_query; + assert(!(query->flags.STUB)); + /* Process answer type */ + const knot_pktsection_t *an = knot_pkt_section(pkt, KNOT_ANSWER); + const knot_dname_t *cname = NULL; + const knot_dname_t *pending_cname = query->sname; + unsigned cname_chain_len = 0; + bool is_final = (query->parent == NULL); + uint32_t iter_count = 0; + bool strict_mode = (query->flags.STRICT); + do { + /* CNAME was found at previous iteration, but records may not follow the correct order. + * Try to find records for pending_cname owner from section start. */ + cname = pending_cname; + pending_cname = NULL; + const int cname_labels = knot_dname_labels(cname, NULL); + for (unsigned i = 0; i < an->count; ++i) { + const knot_rrset_t *rr = knot_pkt_rr(an, i); + + /* Skip the RR if its owner+type doesn't interest us. */ + const uint16_t type = kr_rrset_type_maysig(rr); + const bool type_OK = rr->type == query->stype || type == query->stype + || type == KNOT_RRTYPE_CNAME || type == KNOT_RRTYPE_DNAME; + /* TODO: actually handle DNAMEs */ + if (rr->rclass != KNOT_CLASS_IN || !type_OK + || !knot_dname_is_equal(rr->owner, cname) + || knot_dname_in_bailiwick(rr->owner, query->zone_cut.name) < 0) { + continue; + } + + if (rr->type == KNOT_RRTYPE_RRSIG) { + int rrsig_labels = knot_rrsig_labels(rr->rrs.rdata); + if (rrsig_labels > cname_labels) { + /* clearly wrong RRSIG, don't pick it. + * don't fail immediately, + * let validator work. */ + continue; + } + if (rrsig_labels < cname_labels) { + query->flags.DNSSEC_WEXPAND = true; + } + } + + /* Process records matching current SNAME */ + int state = KR_STATE_FAIL; + bool to_wire = false; + if (is_final) { + /* if not referral, mark record to be written to final answer */ + to_wire = !referral; + } else { + int cnt_ = 0; + state = update_nsaddr(rr, query->parent, &cnt_); + if (state == KR_STATE_FAIL) { + return state; + } + } + uint8_t rank = get_initial_rank(rr, query, true, + query->flags.FORWARD || referral); + state = kr_ranked_rrarray_add(&req->answ_selected, rr, + rank, to_wire, query->uid, &req->pool); + if (state != kr_ok()) { + return KR_STATE_FAIL; + } + /* Jump to next CNAME target */ + if ((query->stype == KNOT_RRTYPE_CNAME) || (rr->type != KNOT_RRTYPE_CNAME)) { + continue; + } + cname_chain_len += 1; + pending_cname = knot_cname_name(rr->rrs.rdata); + if (!pending_cname) { + break; + } + if (cname_chain_len > an->count || cname_chain_len > KR_CNAME_CHAIN_LIMIT) { + VERBOSE_MSG("<= too long cname chain\n"); + return KR_STATE_FAIL; + } + /* Don't use pending_cname immediately. + * There are can be records for "old" cname. */ + } + if (!pending_cname) { + break; + } + if (knot_dname_is_equal(cname, pending_cname)) { + VERBOSE_MSG("<= cname chain loop\n"); + return KR_STATE_FAIL; + } + /* In strict mode, explicitly fetch each CNAME target. */ + if (strict_mode) { + cname = pending_cname; + break; + } + /* Information outside bailiwick is not trusted. */ + if (knot_dname_in_bailiwick(pending_cname, query->zone_cut.name) < 0) { + cname = pending_cname; + break; + } + /* The validator still can't handle multiple zones in one answer, + * so we only follow if a single label is replaced. + * TODO: this still isn't 100%, as the target might have a NS+DS, + * possibly leading to a SERVFAIL for the in-bailiwick name. */ + const int pending_labels = knot_dname_labels(pending_cname, NULL); + if (pending_labels != cname_labels) { + cname = pending_cname; + break; + } + if (knot_dname_matched_labels(pending_cname, cname) != + (cname_labels - 1)) { + cname = pending_cname; + break; + } + } while (++iter_count < KR_CNAME_CHAIN_LIMIT); + if (iter_count >= KR_CNAME_CHAIN_LIMIT) { + VERBOSE_MSG("<= too long cname chain\n"); + return KR_STATE_FAIL; + } + *cname_ret = cname; + return kr_ok(); +} + +static int process_referral_answer(knot_pkt_t *pkt, struct kr_request *req) +{ + const knot_dname_t *cname = NULL; + int state = unroll_cname(pkt, req, true, &cname); + if (state != kr_ok()) { + return KR_STATE_FAIL; + } + struct kr_query *query = req->current_query; + if (!(query->flags.CACHED)) { + /* If not cached (i.e. got from upstream) + * make sure that this is not an authoritative answer + * (even with AA=1) for other layers. + * There can be answers with AA=1, + * empty answer section and NS in authority. + * Clearing of AA prevents them from + * caching in the packet cache. + * If packet already cached, don't touch him. */ + knot_wire_clear_aa(pkt->wire); + } + state = pick_authority(pkt, req, false); + return state == kr_ok() ? KR_STATE_DONE : KR_STATE_FAIL; +} + +static int process_final(knot_pkt_t *pkt, struct kr_request *req, + const knot_dname_t *cname) +{ + const int pkt_class = kr_response_classify(pkt); + struct kr_query *query = req->current_query; + ranked_rr_array_t *array = &req->answ_selected; + for (size_t i = 0; i < array->len; ++i) { + const knot_rrset_t *rr = array->at[i]->rr; + if (!knot_dname_is_equal(rr->owner, cname)) { + continue; + } + if ((rr->rclass != query->sclass) || + (rr->type != query->stype)) { + continue; + } + const bool to_wire = ((pkt_class & (PKT_NXDOMAIN|PKT_NODATA)) != 0); + const int state = pick_authority(pkt, req, to_wire); + if (state != kr_ok()) { + return KR_STATE_FAIL; + } + if (!array->at[i]->to_wire) { + const size_t last_idx = array->len - 1; + size_t j = i; + ranked_rr_array_entry_t *entry = array->at[i]; + /* Relocate record to the end, after current cname */ + while (j < last_idx) { + array->at[j] = array->at[j + 1]; + ++j; + } + array->at[last_idx] = entry; + entry->to_wire = true; + } + finalize_answer(pkt, query, req); + return KR_STATE_DONE; + } + return kr_ok(); +} + +static int process_answer(knot_pkt_t *pkt, struct kr_request *req) +{ + struct kr_query *query = req->current_query; + + /* Response for minimized QNAME. Note that current iterator's minimization + * is only able ask one label below a zone cut. + * NODATA => may be empty non-terminal, retry (found zone cut) + * NOERROR => found zone cut, retry, except the case described below + * NXDOMAIN => parent is zone cut, retry as a workaround for bad authoritatives + */ + const bool is_final = (query->parent == NULL); + const int pkt_class = kr_response_classify(pkt); + const knot_dname_t * pkt_qname = knot_pkt_qname(pkt); + if (!knot_dname_is_equal(pkt_qname, query->sname) && + (pkt_class & (PKT_NOERROR|PKT_NXDOMAIN|PKT_REFUSED|PKT_NODATA))) { + /* Check for parent server that is authoritative for child zone, + * several CCTLDs where the SLD and TLD have the same name servers */ + const knot_pktsection_t *ans = knot_pkt_section(pkt, KNOT_ANSWER); + if ((pkt_class & (PKT_NOERROR)) && ans->count > 0 && + knot_dname_is_equal(pkt_qname, query->zone_cut.name)) { + VERBOSE_MSG("<= continuing with qname minimization\n"); + } else { + /* fall back to disabling minimization */ + VERBOSE_MSG("<= retrying with non-minimized name\n"); + query->flags.NO_MINIMIZE = true; + } + return KR_STATE_CONSUME; + } + + /* This answer didn't improve resolution chain, therefore must be authoritative (relaxed to negative). */ + if (!is_authoritative(pkt, query)) { + if (!(query->flags.FORWARD) && + pkt_class & (PKT_NXDOMAIN|PKT_NODATA)) { + VERBOSE_MSG("<= lame response: non-auth sent negative response\n"); + return KR_STATE_FAIL; + } + } + + const knot_dname_t *cname = NULL; + /* Process answer type */ + int state = unroll_cname(pkt, req, false, &cname); + if (state != kr_ok()) { + return state; + } + /* Make sure that this is an authoritative answer (even with AA=0) for other layers */ + knot_wire_set_aa(pkt->wire); + /* Either way it resolves current query. */ + query->flags.RESOLVED = true; + /* Follow canonical name as next SNAME. */ + if (!knot_dname_is_equal(cname, query->sname)) { + /* Check if target record has been already copied */ + query->flags.CNAME = true; + if (is_final) { + state = process_final(pkt, req, cname); + if (state != kr_ok()) { + return state; + } + } else if ((query->flags.FORWARD) && + ((query->stype == KNOT_RRTYPE_DS) || + (query->stype == KNOT_RRTYPE_NS))) { + /* CNAME'ed answer for DS or NS subquery. + * Treat it as proof of zonecut nonexistance. */ + return KR_STATE_DONE; + } + VERBOSE_MSG("<= cname chain, following\n"); + /* Check if the same query was followed in the same CNAME chain. */ + for (const struct kr_query *q = query->cname_parent; q != NULL; + q = q->cname_parent) { + if (q->sclass == query->sclass && + q->stype == query->stype && + knot_dname_is_equal(q->sname, cname)) { + VERBOSE_MSG("<= cname chain loop\n"); + return KR_STATE_FAIL; + } + } + struct kr_query *next = kr_rplan_push(&req->rplan, query->parent, cname, query->sclass, query->stype); + if (!next) { + return KR_STATE_FAIL; + } + next->flags.AWAIT_CUT = true; + + /* Copy transitive flags from original query to CNAME followup. */ + next->flags.TRACE = query->flags.TRACE; + next->flags.ALWAYS_CUT = query->flags.ALWAYS_CUT; + next->flags.NO_MINIMIZE = query->flags.NO_MINIMIZE; + next->flags.NO_THROTTLE = query->flags.NO_THROTTLE; + + if (query->flags.FORWARD) { + next->forward_flags.CNAME = true; + if (query->parent == NULL) { + state = kr_nsrep_copy_set(&next->ns, &query->ns); + if (state != kr_ok()) { + return KR_STATE_FAIL; + } + } + } + next->cname_parent = query; + /* Want DNSSEC if and only if it's posible to secure + * this name (i.e. iff it is covered by a TA) */ + if (kr_ta_covers_qry(req->ctx, cname, query->stype)) { + next->flags.DNSSEC_WANT = true; + } else { + next->flags.DNSSEC_WANT = false; + } + if (!(query->flags.FORWARD) || + (query->flags.DNSSEC_WEXPAND)) { + state = pick_authority(pkt, req, false); + if (state != kr_ok()) { + return KR_STATE_FAIL; + } + } + } else if (!query->parent) { + /* Answer for initial query */ + const bool to_wire = ((pkt_class & (PKT_NXDOMAIN|PKT_NODATA)) != 0); + state = pick_authority(pkt, req, to_wire); + if (state != kr_ok()) { + return KR_STATE_FAIL; + } + finalize_answer(pkt, query, req); + } else { + /* Answer for sub-query; DS, IP for NS etc. + * It may contains NSEC \ NSEC3 records for + * data non-existence or wc expansion proving. + * If yes, they must be validated by validator. + * If no, authority section is unuseful. + * dnssec\nsec.c & dnssec\nsec3.c use + * rrsets from incoming packet. + * validator uses answer_selected & auth_selected. + * So, if nsec\nsec3 records are present in authority, + * pick_authority() must be called. + * TODO refactor nsec\nsec3 modules to work with + * answer_selected & auth_selected instead of incoming pkt. */ + bool auth_is_unuseful = true; + const knot_pktsection_t *ns = knot_pkt_section(pkt, KNOT_AUTHORITY); + for (unsigned i = 0; i < ns->count; ++i) { + const knot_rrset_t *rr = knot_pkt_rr(ns, i); + if (rr->type == KNOT_RRTYPE_NSEC || + rr->type == KNOT_RRTYPE_NSEC3) { + auth_is_unuseful = false; + break; + } + } + if (!auth_is_unuseful) { + state = pick_authority(pkt, req, false); + if (state != kr_ok()) { + return KR_STATE_FAIL; + } + } + } + return KR_STATE_DONE; +} + +/** @internal like process_answer() but for the STUB mode. */ +static int process_stub(knot_pkt_t *pkt, struct kr_request *req) +{ + struct kr_query *query = req->current_query; + assert(query->flags.STUB); + /* Pick all answer RRs. */ + const knot_pktsection_t *an = knot_pkt_section(pkt, KNOT_ANSWER); + for (unsigned i = 0; i < an->count; ++i) { + const knot_rrset_t *rr = knot_pkt_rr(an, i); + int err = kr_ranked_rrarray_add(&req->answ_selected, rr, + KR_RANK_OMIT | KR_RANK_AUTH, true, query->uid, &req->pool); + /* KR_RANK_AUTH: we don't have the records directly from + * an authoritative source, but we do trust the server and it's + * supposed to only send us authoritative records. */ + if (err != kr_ok()) { + return KR_STATE_FAIL; + } + } + + knot_wire_set_aa(pkt->wire); + query->flags.RESOLVED = true; + /* Pick authority RRs. */ + int pkt_class = kr_response_classify(pkt); + const bool to_wire = ((pkt_class & (PKT_NXDOMAIN|PKT_NODATA)) != 0); + int err = pick_authority(pkt, req, to_wire); + if (err != kr_ok()) { + return KR_STATE_FAIL; + } + + finalize_answer(pkt, query, req); + return KR_STATE_DONE; +} + + +/** Error handling, RFC1034 5.3.3, 4d. */ +static int resolve_error(knot_pkt_t *pkt, struct kr_request *req) +{ + return KR_STATE_FAIL; +} + +/* State-less single resolution iteration step, not needed. */ +static int reset(kr_layer_t *ctx) { return KR_STATE_PRODUCE; } + +/* Set resolution context and parameters. */ +static int begin(kr_layer_t *ctx) +{ + if (ctx->state & (KR_STATE_DONE|KR_STATE_FAIL)) { + return ctx->state; + } + /* + * RFC7873 5.4 extends the QUERY operation code behaviour in order to + * be able to generate requests for server cookies. Such requests have + * QDCOUNT equal to zero and must contain a cookie option. + * Server cookie queries must be handled by the cookie module/layer + * before this layer. + */ + const knot_pkt_t *pkt = ctx->req->qsource.packet; + if (!pkt || knot_wire_get_qdcount(pkt->wire) == 0) { + return KR_STATE_FAIL; + } + + struct kr_query *qry = ctx->req->current_query; + /* Avoid any other classes, and avoid any meta-types ~~except for ANY~~. */ + if (qry->sclass != KNOT_CLASS_IN + || (knot_rrtype_is_metatype(qry->stype) + /* && qry->stype != KNOT_RRTYPE_ANY hmm ANY seems broken ATM */)) { + knot_wire_set_rcode(ctx->req->answer->wire, KNOT_RCODE_NOTIMPL); + return KR_STATE_FAIL; + } + + return reset(ctx); +} + +int kr_make_query(struct kr_query *query, knot_pkt_t *pkt) +{ + /* Minimize QNAME (if possible). */ + uint16_t qtype = query->stype; + const knot_dname_t *qname = minimized_qname(query, &qtype); + + /* Form a query for the authoritative. */ + knot_pkt_clear(pkt); + int ret = knot_pkt_put_question(pkt, qname, query->sclass, qtype); + if (ret != KNOT_EOK) { + return ret; + } + + /* Query built, expect answer. */ + query->id = kr_rand_bytes(2); + /* We must respect https://tools.ietf.org/html/rfc7766#section-6.2.1 + * - When sending multiple queries over a TCP connection, clients MUST NOT + * reuse the DNS Message ID of an in-flight query on that connection. + * + * So, if query is going to be sent over TCP connection + * this id can be changed to avoid duplication with query that already was sent + * but didn't receive answer yet. + */ + knot_wire_set_id(pkt->wire, query->id); + pkt->parsed = pkt->size; + + return kr_ok(); +} + +static int prepare_query(kr_layer_t *ctx, knot_pkt_t *pkt) +{ + assert(pkt && ctx); + struct kr_request *req = ctx->req; + struct kr_query *query = req->current_query; + if (!query || ctx->state & (KR_STATE_DONE|KR_STATE_FAIL)) { + return ctx->state; + } + + /* Make query */ + int ret = kr_make_query(query, pkt); + if (ret != 0) { + return KR_STATE_FAIL; + } + + WITH_VERBOSE(query) { + KR_DNAME_GET_STR(name_str, query->sname); + KR_RRTYPE_GET_STR(type_str, query->stype); + QVERBOSE_MSG(query, "'%s' type '%s' new uid was assigned .%02u, parent uid .%02u\n", + name_str, type_str, req->rplan.next_uid, + query->parent ? query->parent->uid : 0); + } + + query->uid = req->rplan.next_uid; + req->rplan.next_uid += 1; + + return KR_STATE_CONSUME; +} + +static int resolve_badmsg(knot_pkt_t *pkt, struct kr_request *req, struct kr_query *query) +{ + +#ifndef STRICT_MODE + /* Work around broken auths/load balancers */ + if (query->flags.SAFEMODE) { + return resolve_error(pkt, req); + } else if (query->flags.NO_MINIMIZE) { + query->flags.SAFEMODE = true; + return KR_STATE_DONE; + } else { + query->flags.NO_MINIMIZE = true; + return KR_STATE_DONE; + } +#else + return resolve_error(pkt, req); +#endif +} + +static int resolve_notimpl(knot_pkt_t *pkt, struct kr_request *req, struct kr_query *qry) +{ + if (qry->stype == KNOT_RRTYPE_RRSIG && qry->parent != NULL) { + /* RRSIG subquery have got NOTIMPL. + * Possible scenario - same NS is autoritative for child and parent, + * but child isn't signed. + * We got delegation to parent, + * then NS responded as NS for child zone. + * Answer contained record been requested, but no RRSIGs, + * Validator issued RRSIG query then. If qname is zone name, + * we can get NOTIMPL. Ask for DS to find out security status. + * TODO - maybe it would be better to do this in validator, when + * RRSIG revalidation occurs. + */ + struct kr_rplan *rplan = &req->rplan; + struct kr_query *next = kr_rplan_push(rplan, qry->parent, qry->sname, + qry->sclass, KNOT_RRTYPE_DS); + if (!next) { + return KR_STATE_FAIL; + } + kr_zonecut_set(&next->zone_cut, qry->parent->zone_cut.name); + kr_zonecut_copy(&next->zone_cut, &qry->parent->zone_cut); + kr_zonecut_copy_trust(&next->zone_cut, &qry->parent->zone_cut); + next->flags.DNSSEC_WANT = true; + qry->flags.RESOLVED = true; + return KR_STATE_DONE; + } + return resolve_badmsg(pkt, req, qry); +} + +/** Resolve input query or continue resolution with followups. + * + * This roughly corresponds to RFC1034, 5.3.3 4a-d. + */ +static int resolve(kr_layer_t *ctx, knot_pkt_t *pkt) +{ + assert(pkt && ctx); + struct kr_request *req = ctx->req; + struct kr_query *query = req->current_query; + if (!query) { + return ctx->state; + } + + WITH_VERBOSE(query) { + if (query->flags.TRACE) { + auto_free char *pkt_text = kr_pkt_text(pkt); + VERBOSE_MSG("<= answer received: \n%s\n", pkt_text); + } + } + + if (query->flags.RESOLVED || query->flags.BADCOOKIE_AGAIN) { + return ctx->state; + } + + /* Check for packet processing errors first. + * Note - we *MUST* check if it has at least a QUESTION, + * otherwise it would crash on accessing QNAME. */ +#ifdef STRICT_MODE + if (pkt->parsed < pkt->size) { + VERBOSE_MSG("<= pkt contains excessive data\n"); + return resolve_badmsg(pkt, req, query); + } else +#endif + if (pkt->parsed <= KNOT_WIRE_HEADER_SIZE) { + VERBOSE_MSG("<= malformed response\n"); + return resolve_badmsg(pkt, req, query); + } else if (!is_paired_to_query(pkt, query)) { + VERBOSE_MSG("<= ignoring mismatching response\n"); + /* Force TCP, to work around authoritatives messing up question + * without yielding to spoofed responses. */ + query->flags.TCP = true; + return resolve_badmsg(pkt, req, query); + } else if (knot_wire_get_tc(pkt->wire)) { + VERBOSE_MSG("<= truncated response, failover to TCP\n"); + if (query) { + /* Fail if already on TCP. */ + if (query->flags.TCP) { + VERBOSE_MSG("<= TC=1 with TCP, bailing out\n"); + return resolve_error(pkt, req); + } + query->flags.TCP = true; + } + return KR_STATE_CONSUME; + } + +#ifndef NOVERBOSELOG + const knot_lookup_t *rcode = knot_lookup_by_id(knot_rcode_names, knot_wire_get_rcode(pkt->wire)); +#endif + + /* Check response code. */ + switch(knot_wire_get_rcode(pkt->wire)) { + case KNOT_RCODE_NOERROR: + case KNOT_RCODE_NXDOMAIN: + break; /* OK */ + case KNOT_RCODE_REFUSED: + case KNOT_RCODE_SERVFAIL: { + if (query->flags.STUB) { + /* Pass through in stub mode */ + break; + } + VERBOSE_MSG("<= rcode: %s\n", rcode ? rcode->name : "??"); + query->fails += 1; + if (query->fails >= KR_QUERY_NSRETRY_LIMIT) { + query->fails = 0; /* Reset per-query counter. */ + return resolve_error(pkt, req); + } else { + if (!query->flags.FORWARD) { + query->flags.NO_MINIMIZE = true; /* Drop minimisation as a safe-guard. */ + } + return KR_STATE_CONSUME; + } + } + case KNOT_RCODE_FORMERR: + VERBOSE_MSG("<= rcode: %s\n", rcode ? rcode->name : "??"); + return resolve_badmsg(pkt, req, query); + case KNOT_RCODE_NOTIMPL: + VERBOSE_MSG("<= rcode: %s\n", rcode ? rcode->name : "??"); + return resolve_notimpl(pkt, req, query); + default: + VERBOSE_MSG("<= rcode: %s\n", rcode ? rcode->name : "??"); + return resolve_error(pkt, req); + } + + /* Forwarding/stub mode is special. */ + if (query->flags.STUB) { + return process_stub(pkt, req); + } + + /* Resolve authority to see if it's referral or authoritative. */ + int state = process_authority(pkt, req); + switch(state) { + case KR_STATE_CONSUME: /* Not referral, process answer. */ + VERBOSE_MSG("<= rcode: %s\n", rcode ? rcode->name : "??"); + state = process_answer(pkt, req); + break; + case KR_STATE_DONE: /* Referral */ + state = process_referral_answer(pkt,req); + VERBOSE_MSG("<= referral response, follow\n"); + break; + default: + break; + } + + return state; +} + +/** Module implementation. */ +const kr_layer_api_t *iterate_layer(struct kr_module *module) +{ + static const kr_layer_api_t _layer = { + .begin = &begin, + .reset = &reset, + .consume = &resolve, + .produce = &prepare_query + }; + return &_layer; +} + +KR_MODULE_EXPORT(iterate) + +#undef VERBOSE_MSG diff --git a/lib/layer/iterate.h b/lib/layer/iterate.h new file mode 100644 index 0000000..a9395bf --- /dev/null +++ b/lib/layer/iterate.h @@ -0,0 +1,36 @@ +/* Copyright (C) 2014-2017 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz> + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. + */ + +#pragma once + +#include "lib/layer.h" +#include "lib/rplan.h" + +/* Packet classification. */ +enum { + PKT_NOERROR = 1 << 0, /* Positive response */ + PKT_NODATA = 1 << 1, /* No data response */ + PKT_NXDOMAIN = 1 << 2, /* Negative response */ + PKT_REFUSED = 1 << 3, /* Refused response */ + PKT_ERROR = 1 << 4 /* Bad message */ +}; + +/** Classify response by type. */ +int kr_response_classify(const knot_pkt_t *pkt); + +/** Make next iterative query. */ +KR_EXPORT +int kr_make_query(struct kr_query *query, knot_pkt_t *pkt); diff --git a/lib/layer/validate.c b/lib/layer/validate.c new file mode 100644 index 0000000..55c3ad7 --- /dev/null +++ b/lib/layer/validate.c @@ -0,0 +1,1133 @@ +/* Copyright (C) 2014-2017 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz> + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. + */ + +#include <assert.h> +#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.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" + +#define VERBOSE_MSG(qry, ...) QRVERBOSE(qry, "vldr", __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 struct kr_query *qry, + const knot_rrset_t *rr, const char *msg) { + WITH_VERBOSE(qry) { + auto_free char *name_text = kr_dname_text(rr->owner); + auto_free char *type_text = kr_rrtype_text(rr->type); + VERBOSE_MSG(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); + } +} + +static int validate_section(kr_rrset_validation_ctx_t *vctx, const struct kr_query *qry, + knot_mm_t *pool) +{ + 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; + + int validation_result = 0; + for (ssize_t i = 0; i < vctx->rrs->len; ++i) { + ranked_rr_array_entry_t *entry = vctx->rrs->at[i]; + const knot_rrset_t *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 (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; + } + kr_rank_set(&entry->rank, KR_RANK_OMIT); + continue; + } + + uint8_t rank_orig = entry->rank; + validation_result = kr_rrset_validate(vctx, rr); + if (validation_result == kr_ok()) { + kr_rank_set(&entry->rank, KR_RANK_SECURE); + + } else if (kr_rank_test(rank_orig, KR_RANK_TRY)) { + log_bogus_rrsig(vctx, qry, rr, + "failed to validate non-authoritative data but 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)) { + /* no RRSIGs found */ + kr_rank_set(&entry->rank, KR_RANK_MISSING); + vctx->err_cnt += 1; + log_bogus_rrsig(vctx, qry, rr, "no valid RRSIGs found"); + } else { + kr_rank_set(&entry->rank, KR_RANK_BOGUS); + vctx->err_cnt += 1; + log_bogus_rrsig(vctx, qry, 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, + .qry_uid = qry->uid, + .has_nsec3 = has_nsec3, + .flags = 0, + .err_cnt = 0, + .result = 0 + }; + + int 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)) { + + 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, + .qry_uid = qry->uid, + .has_nsec3 = has_nsec3, + .flags = 0, + .result = 0 + }; + int ret = kr_dnskeys_trusted(&vctx, qry->zone_cut.trust_anchor); + if (ret != 0) { + if (ret != kr_error(DNSSEC_INVALID_DS_ALGORITHM) && + ret != kr_error(EAGAIN)) { + log_bogus_rrsig(&vctx, qry, qry->zone_cut.key, "bogus key"); + } + knot_rrset_free(qry->zone_cut.key, qry->zone_cut.pool); + qry->zone_cut.key = NULL; + 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; + assert(parent); + 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(answer); + } else { + /* No-data answer */ + ret = kr_nsec_existence_denial(answer, KNOT_AUTHORITY, proved_name, KNOT_RRTYPE_DS); + } + } 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"); + qry->flags.DNSSEC_BOGUS = true; + } else if (proved_name[0] != '\0') { /* don't go to insecure for . DS */ + VERBOSE_MSG(qry, "<= DS doesn't exist, going insecure\n"); + 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) +{ + 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) { + return knot_rrsig_signer_name(rr->rrs.rdata); + } + } + 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); + if (!signer_name) { + signer_name = find_first_signer(&req->auth_selected); + } + return signer_name; +} + +static int rrsig_not_found(kr_layer_t *ctx, const knot_rrset_t *rr) +{ + struct kr_request *req = ctx->req; + struct kr_query *qry = req->current_query; + + /* Parent-side record, so don't ask for RRSIG. + * We won't receive it anyway. */ + if (qry->stype == KNOT_RRTYPE_DS) { + return KR_STATE_FAIL; + } + + struct kr_zonecut *cut = &qry->zone_cut; + const knot_dname_t *cut_name_start = qry->zone_cut.name; + bool use_cut = true; + if (knot_dname_in_bailiwick(rr->owner, cut_name_start) < 0) { + int zone_labels = knot_dname_labels(qry->zone_cut.name, NULL); + int matched_labels = knot_dname_matched_labels(qry->zone_cut.name, rr->owner); + int skip_labels = zone_labels - matched_labels; + while (skip_labels--) { + cut_name_start = knot_wire_next_label(cut_name_start, NULL); + } + /* try to find the name wanted among ancestors */ + use_cut = false; + while (cut->parent) { + cut = cut->parent; + if (knot_dname_is_equal(cut_name_start, cut->name)) { + use_cut = true; + break; + } + }; + } + struct kr_rplan *rplan = &req->rplan; + struct kr_query *next = kr_rplan_push(rplan, qry, rr->owner, rr->rclass, KNOT_RRTYPE_RRSIG); + if (!next) { + return KR_STATE_FAIL; + } + kr_zonecut_init(&next->zone_cut, cut_name_start, &req->pool); + if (use_cut) { + kr_zonecut_copy(&next->zone_cut, cut); + kr_zonecut_copy_trust(&next->zone_cut, cut); + } else { + next->flags.AWAIT_CUT = true; + } + if (qry->flags.FORWARD) { + next->flags.AWAIT_CUT = false; + } + next->flags.DNSSEC_WANT = true; + return KR_STATE_YIELD; +} + +static int check_validation_result(kr_layer_t *ctx, 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"); + 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, rr); + } else if (!kr_rank_test(invalid_entry->rank, KR_RANK_SECURE)) { + 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) { + assert(qry->cname_parent); + 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) { + assert(qry->cname_parent); + 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. + * + * 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(kr_layer_t *ctx, enum kr_rank rank_to_set, + const knot_dname_t *bailiwick) +{ + 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 (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 (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. */ + /* @todo: Validating stub resolver mode. */ + if (qry->flags.STUB) { + rank_records(ctx, 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(ctx, 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 unsecure 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(ctx, 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"); + 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"); + 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) { + 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 == kr_error(DNSSEC_INVALID_DS_ALGORITHM)) { + VERBOSE_MSG(qry, ">< all DS entries use unsupported algorithm pairs, going insecure\n"); + /* ^ the message is a bit imprecise to avoid being too verbose */ + qry->flags.DNSSEC_WANT = false; + qry->flags.DNSSEC_INSECURE = true; + rank_records(ctx, KR_RANK_INSECURE, qry->zone_cut.name); + mark_insecure_parents(qry); + return KR_STATE_DONE; + } else if (ret != 0) { + VERBOSE_MSG(qry, "<= bad keys, broken trust chain\n"); + qry->flags.DNSSEC_BOGUS = true; + return KR_STATE_FAIL; + } + } + + /* 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_name_error_response_check(pkt, KNOT_AUTHORITY, qry->sname); + } 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"); + 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_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(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 insecured */ + } else { + VERBOSE_MSG(qry, "<= bad NODATA proof\n"); + 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. */ + if (!(qry->flags.CACHED)) { + ret = validate_records(req, pkt, req->rplan.pool, has_nsec3); + if (ret != 0) { + /* something exceptional - no DNS key, empty pointers etc + * normally it shoudn't happen */ + VERBOSE_MSG(qry, "<= couldn't validate RRSIGs\n"); + qry->flags.DNSSEC_BOGUS = true; + return KR_STATE_FAIL; + } + /* check validation state and spawn subrequests */ + if (!req->answ_validated) { + ret = check_validation_result(ctx, &req->answ_selected); + if (ret != KR_STATE_DONE) { + return ret; + } + } + if (!req->auth_validated) { + ret = check_validation_result(ctx, &req->auth_selected); + if (ret != KR_STATE_DONE) { + return ret; + } + } + } + + 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"); + 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-existance */ + 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; +} +/** Module implementation. */ +const kr_layer_api_t *validate_layer(struct kr_module *module) +{ + static const kr_layer_api_t _layer = { + .consume = &validate, + }; + /* Store module reference */ + return &_layer; +} + +int validate_init(struct kr_module *module) +{ + return kr_ok(); +} + +KR_MODULE_EXPORT(validate) + +#undef VERBOSE_MSG |