/* * validator/validator.c - secure validator DNS query response module * * Copyright (c) 2007, NLnet Labs. All rights reserved. * * This software is open source. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * Neither the name of the NLNET LABS nor the names of its contributors may * be used to endorse or promote products derived from this software without * specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ /** * \file * * This file contains a module that performs validation of DNS queries. * According to RFC 4034. */ #include "config.h" #include "validator/validator.h" #include "validator/val_anchor.h" #include "validator/val_kcache.h" #include "validator/val_kentry.h" #include "validator/val_utils.h" #include "validator/val_nsec.h" #include "validator/val_nsec3.h" #include "services/cache/dns.h" #include "util/data/dname.h" #include "util/module.h" #include "util/log.h" #include "util/net_help.h" #include "util/region-allocator.h" #include "util/config_file.h" /** fill up nsec3 key iterations config entry */ static int fill_nsec3_iter(struct val_env* ve, char* s, int c) { char* e; int i; free(ve->nsec3_keysize); free(ve->nsec3_maxiter); ve->nsec3_keysize = (size_t*)calloc(sizeof(size_t), (size_t)c); ve->nsec3_maxiter = (size_t*)calloc(sizeof(size_t), (size_t)c); if(!ve->nsec3_keysize || !ve->nsec3_maxiter) { log_err("out of memory"); return 0; } for(i=0; insec3_keysize[i] = (size_t)strtol(s, &e, 10); if(s == e) { log_err("cannot parse: %s", s); return 0; } s = e; ve->nsec3_maxiter[i] = (size_t)strtol(s, &e, 10); if(s == e) { log_err("cannot parse: %s", s); return 0; } s = e; if(i>0 && ve->nsec3_keysize[i-1] >= ve->nsec3_keysize[i]) { log_err("nsec3 key iterations not ascending: %d %d", (int)ve->nsec3_keysize[i-1], (int)ve->nsec3_keysize[i]); return 0; } verbose(VERB_ALGO, "validator nsec3cfg keysz %d mxiter %d", (int)ve->nsec3_keysize[i], (int)ve->nsec3_maxiter[i]); } return 1; } /** apply config settings to validator */ static int val_apply_cfg(struct val_env* val_env, struct config_file* cfg) { int c; val_env->bogus_ttl = (uint32_t)cfg->bogus_ttl; val_env->clean_additional = cfg->val_clean_additional; val_env->permissive_mode = cfg->val_permissive_mode; if(!val_env->anchors) val_env->anchors = anchors_create(); if(!val_env->anchors) { log_err("out of memory"); return 0; } if(!val_env->kcache) val_env->kcache = key_cache_create(cfg); if(!val_env->kcache) { log_err("out of memory"); return 0; } if(!anchors_apply_cfg(val_env->anchors, cfg)) { log_err("validator: error in trustanchors config"); return 0; } val_env->date_override = cfg->val_date_override; c = cfg_count_numbers(cfg->val_nsec3_key_iterations); if(c < 1 || (c&1)) { log_err("validator: unparseable or odd nsec3 key " "iterations: %s", cfg->val_nsec3_key_iterations); return 0; } val_env->nsec3_keyiter_count = c/2; if(!fill_nsec3_iter(val_env, cfg->val_nsec3_key_iterations, c/2)) { log_err("validator: cannot apply nsec3 key iterations"); return 0; } return 1; } /** validator init */ static int val_init(struct module_env* env, int id) { struct val_env* val_env = (struct val_env*)calloc(1, sizeof(struct val_env)); if(!val_env) { log_err("malloc failure"); return 0; } env->modinfo[id] = (void*)val_env; env->need_to_validate = 1; val_env->permissive_mode = 0; if(!val_apply_cfg(val_env, env->cfg)) { log_err("validator: could not apply configuration settings."); return 0; } return 1; } /** validator deinit */ static void val_deinit(struct module_env* env, int id) { struct val_env* val_env; if(!env || !env->modinfo || !env->modinfo[id]) return; val_env = (struct val_env*)env->modinfo[id]; anchors_delete(val_env->anchors); key_cache_delete(val_env->kcache); free(val_env->nsec3_keysize); free(val_env->nsec3_maxiter); free(val_env); } /** allocate new validator query state */ static struct val_qstate* val_new(struct module_qstate* qstate, int id) { struct val_qstate* vq = (struct val_qstate*)region_alloc( qstate->region, sizeof(*vq)); log_assert(!qstate->minfo[id]); if(!vq) return NULL; memset(vq, 0, sizeof(*vq)); qstate->minfo[id] = vq; vq->state = VAL_INIT_STATE; if(!qstate->return_msg || qstate->return_rcode != LDNS_RCODE_NOERROR) { /* create a message to verify */ verbose(VERB_ALGO, "constructing reply for validation"); vq->orig_msg = (struct dns_msg*)region_alloc(qstate->region, sizeof(struct dns_msg)); if(!vq->orig_msg) return NULL; vq->orig_msg->qinfo = qstate->qinfo; vq->orig_msg->rep = (struct reply_info*)region_alloc( qstate->region, sizeof(struct reply_info)); if(!vq->orig_msg->rep) return NULL; memset(vq->orig_msg->rep, 0, sizeof(struct reply_info)); vq->orig_msg->rep->flags = (uint16_t)(qstate->return_rcode&0xf) |BIT_QR|BIT_RA|(qstate->query_flags|(BIT_CD|BIT_RD)); vq->orig_msg->rep->qdcount = 1; } else { vq->orig_msg = qstate->return_msg; } vq->qchase = qstate->qinfo; /* chase reply will be an edited (sub)set of the orig msg rrset ptrs */ vq->chase_reply = region_alloc_init(qstate->region, vq->orig_msg->rep, sizeof(struct reply_info) - sizeof(struct rrset_ref)); if(!vq->chase_reply) return NULL; vq->chase_reply->rrsets = region_alloc_init(qstate->region, vq->orig_msg->rep->rrsets, sizeof(struct ub_packed_rrset_key*) * vq->orig_msg->rep->rrset_count); if(!vq->chase_reply->rrsets) return NULL; vq->rrset_skip = 0; return vq; } /** * Exit validation with an error status * * @param qstate: query state * @param id: validator id. * @return false, for use by caller to return to stop processing. */ static int val_error(struct module_qstate* qstate, int id) { qstate->ext_state[id] = module_error; qstate->return_rcode = LDNS_RCODE_SERVFAIL; return 0; } /** * Check to see if a given response needs to go through the validation * process. Typical reasons for this routine to return false are: CD bit was * on in the original request, the response was already validated, or the * response is a kind of message that is unvalidatable (i.e., SERVFAIL, * REFUSED, etc.) * * @param qstate: query state. * @param ret_rc: rcode for this message (if noerror - examine ret_msg). * @param ret_msg: return msg, can be NULL; look at rcode instead. * @return true if the response could use validation (although this does not * mean we can actually validate this response). */ static int needs_validation(struct module_qstate* qstate, int ret_rc, struct dns_msg* ret_msg) { int rcode; /* If the CD bit is on in the original request, then we don't bother to * validate anything.*/ if(qstate->query_flags & BIT_CD) { verbose(VERB_ALGO, "not validating response due to CD bit"); return 0; } if(ret_rc != LDNS_RCODE_NOERROR || !ret_msg) rcode = ret_rc; else rcode = (int)FLAGS_GET_RCODE(ret_msg->rep->flags); if(rcode != LDNS_RCODE_NOERROR && rcode != LDNS_RCODE_NXDOMAIN) { verbose(VERB_ALGO, "cannot validate non-answer, rcode %s", ldns_lookup_by_id(ldns_rcodes, rcode)? ldns_lookup_by_id(ldns_rcodes, rcode)->name:"??"); return 0; } /* validate unchecked, and re-validate bogus messages */ if (ret_msg && ret_msg->rep->security > sec_status_bogus) { verbose(VERB_ALGO, "response has already been validated"); return 0; } return 1; } /** * Generate a request for DNS data. * * @param qstate: query state that is the parent. * @param id: module id. * @param name: what name to query for. * @param namelen: length of name. * @param qtype: query type. * @param qclass: query class. * @return false on alloc failure. */ static int generate_request(struct module_qstate* qstate, int id, uint8_t* name, size_t namelen, uint16_t qtype, uint16_t qclass) { struct module_qstate* newq; struct query_info ask; ask.qname = name; ask.qname_len = namelen; ask.qtype = qtype; ask.qclass = qclass; log_query_info(VERB_ALGO, "generate request", &ask); if(!(*qstate->env->attach_sub)(qstate, &ask, (uint16_t)(BIT_RD|BIT_CD), 0, &newq)){ log_err("Could not generate request: out of memory"); return 0; } /* ignore newq; validator does not need state created for that * query, and its a 'normal' for iterator as well */ qstate->ext_state[id] = module_wait_subquery; return 1; } /** * Prime trust anchor for use. * Generate and dispatch a priming query for the given trust anchor. * The trust anchor can be DNSKEY or DS and does not have to be signed. * * @param qstate: query state. * @param vq: validator query state. * @param id: module id. * @param toprime: what to prime. * @return false on a processing error. */ static int prime_trust_anchor(struct module_qstate* qstate, struct val_qstate* vq, int id, struct trust_anchor* toprime) { int ret = generate_request(qstate, id, toprime->name, toprime->namelen, LDNS_RR_TYPE_DNSKEY, toprime->dclass); if(!ret) { log_err("Could not prime trust anchor: out of memory"); return 0; } /* ignore newq; validator does not need state created for that * query, and its a 'normal' for iterator as well */ vq->wait_prime_ta = 1; /* to elicit PRIME_RESP_STATE processing from the validator inform_super() routine */ return 1; } /** * Validate if the ANSWER and AUTHORITY sections contain valid rrsets. * They must be validly signed with the given key. * Tries to validate ADDITIONAL rrsets as well, but only to check them. * Allows unsigned CNAME after a DNAME that expands the DNAME. * * Note that by the time this method is called, the process of finding the * trusted DNSKEY rrset that signs this response must already have been * completed. * * @param env: module env for verify. * @param ve: validator env for verify. * @param qchase: query that was made. * @param chase_reply: answer to validate. * @param key_entry: the key entry, which is trusted, and which matches * the signer of the answer. The key entry isgood(). * @return false if any of the rrsets in the an or ns sections of the message * fail to verify. The message is then set to bogus. */ static int validate_msg_signatures(struct module_env* env, struct val_env* ve, struct query_info* qchase, struct reply_info* chase_reply, struct key_entry_key* key_entry) { size_t i; struct ub_packed_rrset_key* s; enum sec_status sec; int dname_seen = 0; /* validate the ANSWER section */ for(i=0; ian_numrrsets; i++) { s = chase_reply->rrsets[i]; /* Skip the CNAME following a (validated) DNAME. * Because of the normalization routines in the iterator, * there will always be an unsigned CNAME following a DNAME * (unless qtype=DNAME). */ if(dname_seen && ntohs(s->rk.type) == LDNS_RR_TYPE_CNAME) { dname_seen = 0; /* CNAME was synthesized by our own iterator */ /* since the DNAME verified, mark the CNAME as secure */ ((struct packed_rrset_data*)s->entry.data)->security = sec_status_secure; ((struct packed_rrset_data*)s->entry.data)->trust = rrset_trust_validated; continue; } /* Verify the answer rrset */ sec = val_verify_rrset_entry(env, ve, s, key_entry); /* If the (answer) rrset failed to validate, then this * message is BAD. */ if(sec != sec_status_secure) { log_nametypeclass(VERB_DETAIL, "validator: response " "has failed ANSWER rrset:", s->rk.dname, ntohs(s->rk.type), ntohs(s->rk.rrset_class)); chase_reply->security = sec_status_bogus; return 0; } /* Notice a DNAME that should be followed by an unsigned * CNAME. */ if(qchase->qtype != LDNS_RR_TYPE_DNAME && ntohs(s->rk.type) == LDNS_RR_TYPE_DNAME) { dname_seen = 1; } } /* validate the AUTHORITY section */ for(i=chase_reply->an_numrrsets; ian_numrrsets+ chase_reply->ns_numrrsets; i++) { s = chase_reply->rrsets[i]; sec = val_verify_rrset_entry(env, ve, s, key_entry); /* If anything in the authority section fails to be secure, * we have a bad message. */ if(sec != sec_status_secure) { log_nametypeclass(VERB_DETAIL, "validator: response " "has failed AUTHORITY rrset:", s->rk.dname, ntohs(s->rk.type), ntohs(s->rk.rrset_class)); chase_reply->security = sec_status_bogus; return 0; } } /* attempt to validate the ADDITIONAL section rrsets */ if(!ve->clean_additional) return 1; for(i=chase_reply->an_numrrsets+chase_reply->ns_numrrsets; irrset_count; i++) { s = chase_reply->rrsets[i]; (void)val_verify_rrset_entry(env, ve, s, key_entry); /* the additional section can fail to be secure, * it is optional, check signature in case we need * to clean the additional section later. */ } return 1; } /** * Given a "positive" response -- a response that contains an answer to the * question, and no CNAME chain, validate this response. * * The answer and authority RRsets must already be verified as secure. * * @param env: module env for verify. * @param ve: validator env for verify. * @param qchase: query that was made. * @param chase_reply: answer to that query to validate. * @param kkey: the key entry, which is trusted, and which matches * the signer of the answer. The key entry isgood(). */ static void validate_positive_response(struct module_env* env, struct val_env* ve, struct query_info* qchase, struct reply_info* chase_reply, struct key_entry_key* kkey) { uint8_t* wc = NULL; int wc_NSEC_ok = 0; int nsec3s_seen = 0; size_t i; struct ub_packed_rrset_key* s; /* validate the ANSWER section - this will be the answer itself */ for(i=0; ian_numrrsets; i++) { s = chase_reply->rrsets[i]; /* Check to see if the rrset is the result of a wildcard * expansion. If so, an additional check will need to be * made in the authority section. */ if(!val_rrset_wildcard(s, &wc)) { log_nametypeclass(VERB_DETAIL, "Positive response has " "inconsistent wildcard sigs:", s->rk.dname, ntohs(s->rk.type), ntohs(s->rk.rrset_class)); chase_reply->security = sec_status_bogus; return; } } /* validate the AUTHORITY section as well - this will generally be * the NS rrset (which could be missing, no problem) */ for(i=chase_reply->an_numrrsets; ian_numrrsets+ chase_reply->ns_numrrsets; i++) { s = chase_reply->rrsets[i]; /* If this is a positive wildcard response, and we have a * (just verified) NSEC record, try to use it to 1) prove * that qname doesn't exist and 2) that the correct wildcard * was used. */ if(wc != NULL && ntohs(s->rk.type) == LDNS_RR_TYPE_NSEC) { if(val_nsec_proves_positive_wildcard(s, qchase, wc)) { wc_NSEC_ok = 1; } /* if not, continue looking for proof */ } /* Otherwise, if this is a positive wildcard response and * we have NSEC3 records */ if(wc != NULL && ntohs(s->rk.type) == LDNS_RR_TYPE_NSEC3) { nsec3s_seen = 1; } } /* If this was a positive wildcard response that we haven't already * proven, and we have NSEC3 records, try to prove it using the NSEC3 * records. */ if(wc != NULL && !wc_NSEC_ok && nsec3s_seen) { enum sec_status sec = nsec3_prove_wildcard(env, ve, chase_reply->rrsets+chase_reply->an_numrrsets, chase_reply->ns_numrrsets, qchase, kkey, wc); if(sec == sec_status_insecure) { verbose(VERB_ALGO, "Positive wildcard response is " "insecure"); chase_reply->security = sec_status_insecure; return; } else if(sec == sec_status_secure) wc_NSEC_ok = 1; } /* If after all this, we still haven't proven the positive wildcard * response, fail. */ if(wc != NULL && !wc_NSEC_ok) { verbose(VERB_DETAIL, "positive response was wildcard " "expansion and did not prove original data " "did not exist"); chase_reply->security = sec_status_bogus; return; } verbose(VERB_ALGO, "Successfully validated positive response"); chase_reply->security = sec_status_secure; } /** * Validate a NOERROR/NODATA signed response -- a response that has a * NOERROR Rcode but no ANSWER section RRsets. This consists of making * certain that the authority section NSEC/NSEC3s proves that the qname * does exist and the qtype doesn't. * * The answer and authority RRsets must already be verified as secure. * * @param env: module env for verify. * @param ve: validator env for verify. * @param qchase: query that was made. * @param chase_reply: answer to that query to validate. * @param kkey: the key entry, which is trusted, and which matches * the signer of the answer. The key entry isgood(). */ static void validate_nodata_response(struct module_env* env, struct val_env* ve, struct query_info* qchase, struct reply_info* chase_reply, struct key_entry_key* kkey) { /* Since we are here, there must be nothing in the ANSWER section to * validate. */ /* (Note: CNAME/DNAME responses will not directly get here -- * instead, they are chased down into indiviual CNAME validations, * and at the end of the cname chain a POSITIVE, or CNAME_NOANSWER * validation.) */ /* validate the AUTHORITY section */ int has_valid_nsec = 0; /* If true, then the NODATA has been proven.*/ uint8_t* ce = NULL; /* for wildcard nodata responses. This is the proven closest encloser. */ uint8_t* wc = NULL; /* for wildcard nodata responses. wildcard nsec */ int nsec3s_seen = 0; /* nsec3s seen */ struct ub_packed_rrset_key* s; size_t i; for(i=chase_reply->an_numrrsets; ian_numrrsets+ chase_reply->ns_numrrsets; i++) { s = chase_reply->rrsets[i]; /* If we encounter an NSEC record, try to use it to prove * NODATA. * This needs to handle the ENT NODATA case. */ if(ntohs(s->rk.type) == LDNS_RR_TYPE_NSEC) { if(nsec_proves_nodata(s, qchase)) { has_valid_nsec = 1; /* set wc only if wildcard applicable, which * is a *.name, and qname sub of .name */ if(dname_is_wild(s->rk.dname) && dname_strict_subdomain_c( qchase->qname, s->rk.dname+2)) wc = s->rk.dname; } if(val_nsec_proves_name_error(s, qchase->qname)) { ce = nsec_closest_encloser(qchase->qname, s); } } else if(ntohs(s->rk.type) == LDNS_RR_TYPE_NSEC3) { nsec3s_seen = 1; } } /* check to see if we have a wildcard NODATA proof. */ /* The wildcard NODATA is 1 NSEC proving that qname does not exist * (and also proving what the closest encloser is), and 1 NSEC * showing the matching wildcard, which must be *.closest_encloser. */ if(wc && !ce) has_valid_nsec = 0; else if(wc && ce) { log_assert(dname_is_wild(wc)); /* first label wc is \001*, so remove and compare to ce */ if(query_dname_compare(wc+2, ce) != 0) { has_valid_nsec = 0; } } if(!has_valid_nsec && nsec3s_seen) { enum sec_status sec = nsec3_prove_nodata(env, ve, chase_reply->rrsets+chase_reply->an_numrrsets, chase_reply->ns_numrrsets, qchase, kkey); if(sec == sec_status_insecure) { verbose(VERB_ALGO, "NODATA response is insecure"); chase_reply->security = sec_status_insecure; return; } else if(sec == sec_status_secure) has_valid_nsec = 1; } if(!has_valid_nsec) { verbose(VERB_DETAIL, "NODATA response failed to prove NODATA " "status with NSEC/NSEC3"); if(verbosity >= VERB_ALGO) log_dns_msg("Failed NODATA", qchase, chase_reply); chase_reply->security = sec_status_bogus; return; } verbose(VERB_ALGO, "successfully validated NODATA response."); chase_reply->security = sec_status_secure; } /** * Validate a NAMEERROR signed response -- a response that has a NXDOMAIN * Rcode. * This consists of making certain that the authority section NSEC proves * that the qname doesn't exist and the covering wildcard also doesn't exist.. * * The answer and authority RRsets must have already been verified as secure. * * @param env: module env for verify. * @param ve: validator env for verify. * @param qchase: query that was made. * @param chase_reply: answer to that query to validate. * @param kkey: the key entry, which is trusted, and which matches * the signer of the answer. The key entry isgood(). */ static void validate_nameerror_response(struct module_env* env, struct val_env* ve, struct query_info* qchase, struct reply_info* chase_reply, struct key_entry_key* kkey) { int has_valid_nsec = 0; int has_valid_wnsec = 0; int nsec3s_seen = 0; struct ub_packed_rrset_key* s; size_t i; for(i=chase_reply->an_numrrsets; ian_numrrsets+ chase_reply->ns_numrrsets; i++) { s = chase_reply->rrsets[i]; if(ntohs(s->rk.type) == LDNS_RR_TYPE_NSEC) { if(val_nsec_proves_name_error(s, qchase->qname)) has_valid_nsec = 1; if(val_nsec_proves_no_wc(s, qchase->qname, qchase->qname_len)) has_valid_wnsec = 1; } else if(ntohs(s->rk.type) == LDNS_RR_TYPE_NSEC3) nsec3s_seen = 1; } if((!has_valid_nsec || !has_valid_wnsec) && nsec3s_seen) { /* use NSEC3 proof, both answer and auth rrsets, in case * NSEC3s end up in the answer (due to qtype=NSEC3 or so) */ chase_reply->security = nsec3_prove_nameerror(env, ve, chase_reply->rrsets, chase_reply->an_numrrsets+ chase_reply->ns_numrrsets, qchase, kkey); if(chase_reply->security != sec_status_secure) { verbose(VERB_DETAIL, "NameError response failed nsec, " "nsec3 proof was %s", sec_status_to_string( chase_reply->security)); return; } has_valid_nsec = 1; has_valid_wnsec = 1; } /* If the message fails to prove either condition, it is bogus. */ if(!has_valid_nsec) { verbose(VERB_DETAIL, "NameError response has failed to prove: " "qname does not exist"); chase_reply->security = sec_status_bogus; return; } if(!has_valid_wnsec) { verbose(VERB_DETAIL, "NameError response has failed to prove: " "covering wildcard does not exist"); chase_reply->security = sec_status_bogus; return; } /* Otherwise, we consider the message secure. */ verbose(VERB_ALGO, "successfully validated NAME ERROR response."); chase_reply->security = sec_status_secure; } /** * Given a referral response, validate rrsets and take least trusted rrset * as the current validation status. * * Note that by the time this method is called, the process of finding the * trusted DNSKEY rrset that signs this response must already have been * completed. * * @param chase_reply: answer to validate. */ static void validate_referral_response(struct reply_info* chase_reply) { size_t i; enum sec_status s; /* message security equals lowest rrset security */ chase_reply->security = sec_status_secure; for(i=0; irrset_count; i++) { s = ((struct packed_rrset_data*)chase_reply->rrsets[i] ->entry.data)->security; if(s < chase_reply->security) chase_reply->security = s; } verbose(VERB_ALGO, "validated part of referral response as %s", sec_status_to_string(chase_reply->security)); } /** * Given an "ANY" response -- a response that contains an answer to a * qtype==ANY question, with answers. This does no checking that all * types are present. * * NOTE: it may be possible to get parent-side delegation point records * here, which won't all be signed. Right now, this routine relies on the * upstream iterative resolver to not return these responses -- instead * treating them as referrals. * * NOTE: RFC 4035 is silent on this issue, so this may change upon * clarification. Clarification draft -05 says to not check all types are * present. * * Note that by the time this method is called, the process of finding the * trusted DNSKEY rrset that signs this response must already have been * completed. * * @param qchase: query that was made. * @param chase_reply: answer to that query to validate. */ static void validate_any_response(struct query_info* qchase, struct reply_info* chase_reply) { if(qchase->qtype != LDNS_RR_TYPE_ANY) { log_err("internal error: ANY validation called for non-ANY"); chase_reply->security = sec_status_bogus; return; } /* all answer and auth rrsets already verified */ verbose(VERB_ALGO, "Successfully validated positive ANY response"); chase_reply->security = sec_status_secure; } /** * Validate CNAME response, or DNAME+CNAME. * This is just like a positive proof, except that this is about a * DNAME+CNAME. Possible wildcard proof. * Difference with positive proof is that this routine refuses * wildcarded DNAMEs. * * The answer and authority rrsets must already be verified as secure. * * @param env: module env for verify. * @param ve: validator env for verify. * @param qchase: query that was made. * @param chase_reply: answer to that query to validate. * @param kkey: the key entry, which is trusted, and which matches * the signer of the answer. The key entry isgood(). */ static void validate_cname_response(struct module_env* env, struct val_env* ve, struct query_info* qchase, struct reply_info* chase_reply, struct key_entry_key* kkey) { uint8_t* wc = NULL; int wc_NSEC_ok = 0; int nsec3s_seen = 0; size_t i; struct ub_packed_rrset_key* s; /* validate the ANSWER section - this will be the CNAME (+DNAME) */ for(i=0; ian_numrrsets; i++) { s = chase_reply->rrsets[i]; /* Check to see if the rrset is the result of a wildcard * expansion. If so, an additional check will need to be * made in the authority section. */ if(!val_rrset_wildcard(s, &wc)) { log_nametypeclass(VERB_DETAIL, "Cname response has " "inconsistent wildcard sigs:", s->rk.dname, ntohs(s->rk.type), ntohs(s->rk.rrset_class)); chase_reply->security = sec_status_bogus; return; } /* Refuse wildcarded DNAMEs rfc 4597. * Do not follow a wildcarded DNAME because * its synthesized CNAME expansion is underdefined */ if(qchase->qtype != LDNS_RR_TYPE_DNAME && ntohs(s->rk.type) == LDNS_RR_TYPE_DNAME && wc) { log_nametypeclass(VERB_DETAIL, "cannot validate a " "wildcarded DNAME:", s->rk.dname, ntohs(s->rk.type), ntohs(s->rk.rrset_class)); chase_reply->security = sec_status_bogus; return; } } /* AUTHORITY section */ for(i=chase_reply->an_numrrsets; ian_numrrsets+ chase_reply->ns_numrrsets; i++) { s = chase_reply->rrsets[i]; /* If this is a positive wildcard response, and we have a * (just verified) NSEC record, try to use it to 1) prove * that qname doesn't exist and 2) that the correct wildcard * was used. */ if(wc != NULL && ntohs(s->rk.type) == LDNS_RR_TYPE_NSEC) { if(val_nsec_proves_positive_wildcard(s, qchase, wc)) { wc_NSEC_ok = 1; } /* if not, continue looking for proof */ } /* Otherwise, if this is a positive wildcard response and * we have NSEC3 records */ if(wc != NULL && ntohs(s->rk.type) == LDNS_RR_TYPE_NSEC3) { nsec3s_seen = 1; } } /* If this was a positive wildcard response that we haven't already * proven, and we have NSEC3 records, try to prove it using the NSEC3 * records. */ if(wc != NULL && !wc_NSEC_ok && nsec3s_seen) { enum sec_status sec = nsec3_prove_wildcard(env, ve, chase_reply->rrsets+chase_reply->an_numrrsets, chase_reply->ns_numrrsets, qchase, kkey, wc); if(sec == sec_status_insecure) { verbose(VERB_ALGO, "wildcard CNAME response is " "insecure"); chase_reply->security = sec_status_insecure; return; } else if(sec == sec_status_secure) wc_NSEC_ok = 1; } /* If after all this, we still haven't proven the positive wildcard * response, fail. */ if(wc != NULL && !wc_NSEC_ok) { verbose(VERB_DETAIL, "CNAME response was wildcard " "expansion and did not prove original data " "did not exist"); chase_reply->security = sec_status_bogus; return; } verbose(VERB_ALGO, "Successfully validated CNAME response"); chase_reply->security = sec_status_secure; } /** * Validate CNAME NOANSWER response, no more data after a CNAME chain. * This can be a NODATA or a NAME ERROR case, but not both at the same time. * We don't know because the rcode has been set to NOERROR by the CNAME. * * The answer and authority rrsets must already be verified as secure. * * @param env: module env for verify. * @param ve: validator env for verify. * @param qchase: query that was made. * @param chase_reply: answer to that query to validate. * @param kkey: the key entry, which is trusted, and which matches * the signer of the answer. The key entry isgood(). */ static void validate_cname_noanswer_response(struct module_env* env, struct val_env* ve, struct query_info* qchase, struct reply_info* chase_reply, struct key_entry_key* kkey) { int nodata_valid_nsec = 0; /* If true, then NODATA has been proven.*/ uint8_t* ce = NULL; /* for wildcard nodata responses. This is the proven closest encloser. */ uint8_t* wc = NULL; /* for wildcard nodata responses. wildcard nsec */ int nxdomain_valid_nsec = 0; /* if true, namerror has been proven */ int nxdomain_valid_wnsec = 0; int nsec3s_seen = 0; /* nsec3s seen */ struct ub_packed_rrset_key* s; size_t i; /* the AUTHORITY section */ for(i=chase_reply->an_numrrsets; ian_numrrsets+ chase_reply->ns_numrrsets; i++) { s = chase_reply->rrsets[i]; /* If we encounter an NSEC record, try to use it to prove * NODATA. This needs to handle the ENT NODATA case. * Also try to prove NAMEERROR, and absence of a wildcard */ if(ntohs(s->rk.type) == LDNS_RR_TYPE_NSEC) { if(nsec_proves_nodata(s, qchase)) { nodata_valid_nsec = 1; /* set wc only if wildcard applicable, which * is a *.name, and qname sub of .name */ if(dname_is_wild(s->rk.dname) && dname_strict_subdomain_c( qchase->qname, s->rk.dname+2)) wc = s->rk.dname; } if(val_nsec_proves_name_error(s, qchase->qname)) { ce = nsec_closest_encloser(qchase->qname, s); nxdomain_valid_nsec = 1; } if(val_nsec_proves_no_wc(s, qchase->qname, qchase->qname_len)) nxdomain_valid_wnsec = 1; } else if(ntohs(s->rk.type) == LDNS_RR_TYPE_NSEC3) { nsec3s_seen = 1; } } /* check to see if we have a wildcard NODATA proof. */ /* The wildcard NODATA is 1 NSEC proving that qname does not exists * (and also proving what the closest encloser is), and 1 NSEC * showing the matching wildcard, which must be *.closest_encloser. */ if(wc && !ce) nodata_valid_nsec = 0; else if(wc && ce) { log_assert(dname_is_wild(wc)); /* first label wc is \001*, so remove and compare to ce */ if(query_dname_compare(wc+2, ce) != 0) { nodata_valid_nsec = 0; } } if(nxdomain_valid_nsec && !nxdomain_valid_wnsec) { /* name error is missing wildcard denial proof */ nxdomain_valid_nsec = 0; } if(nodata_valid_nsec && nxdomain_valid_nsec) { verbose(VERB_DETAIL, "CNAMEchain to noanswer proves that name " "exists and not exists, bogus"); chase_reply->security = sec_status_bogus; return; } if(!nodata_valid_nsec && !nxdomain_valid_nsec && nsec3s_seen) { int nodata; enum sec_status sec = nsec3_prove_nxornodata(env, ve, chase_reply->rrsets+chase_reply->an_numrrsets, chase_reply->ns_numrrsets, qchase, kkey, &nodata); if(sec == sec_status_insecure) { verbose(VERB_ALGO, "CNAMEchain to noanswer response " "is insecure"); chase_reply->security = sec_status_insecure; return; } else if(sec == sec_status_secure) { if(nodata) nodata_valid_nsec = 1; else nxdomain_valid_nsec = 1; } } if(!nodata_valid_nsec && !nxdomain_valid_nsec) { verbose(VERB_DETAIL, "CNAMEchain to noanswer response failed " "to prove status with NSEC/NSEC3"); if(verbosity >= VERB_ALGO) log_dns_msg("Failed CNAMEnoanswer", qchase, chase_reply); chase_reply->security = sec_status_bogus; return; } if(nodata_valid_nsec) verbose(VERB_ALGO, "successfully validated CNAME chain to a " "NODATA response."); else verbose(VERB_ALGO, "successfully validated CNAME chain to a " "NAMEERROR response."); chase_reply->security = sec_status_secure; } /** * Process init state for validator. * Process the INIT state. First tier responses start in the INIT state. * This is where they are vetted for validation suitability, and the initial * key search is done. * * Currently, events the come through this routine will be either promoted * to FINISHED/CNAME_RESP (no validation needed), FINDKEY (next step to * validation), or will be (temporarily) retired and a new priming request * event will be generated. * * @param qstate: query state. * @param vq: validator query state. * @param ve: validator shared global environment. * @param id: module id. * @return true if the event should be processed further on return, false if * not. */ static int processInit(struct module_qstate* qstate, struct val_qstate* vq, struct val_env* ve, int id) { uint8_t* lookup_name; size_t lookup_len; enum val_classification subtype = val_classify_response( qstate->query_flags, &vq->qchase, vq->orig_msg->rep, vq->rrset_skip); if(subtype == VAL_CLASS_REFERRAL && vq->rrset_skip < vq->orig_msg->rep->rrset_count) { /* referral uses the rrset name as qchase, to find keys for * that rrset */ vq->qchase.qname = vq->orig_msg->rep-> rrsets[vq->rrset_skip]->rk.dname; vq->qchase.qname_len = vq->orig_msg->rep-> rrsets[vq->rrset_skip]->rk.dname_len; vq->qchase.qtype = ntohs(vq->orig_msg->rep-> rrsets[vq->rrset_skip]->rk.type); vq->qchase.qclass = ntohs(vq->orig_msg->rep-> rrsets[vq->rrset_skip]->rk.rrset_class); /* for type DS look at the parent side for keys/trustanchor */ /* also for NSEC not at apex */ if(vq->qchase.qtype == LDNS_RR_TYPE_DS || (vq->qchase.qtype == LDNS_RR_TYPE_NSEC && !(vq->orig_msg->rep->rrsets[vq->rrset_skip]-> rk.flags&PACKED_RRSET_NSEC_AT_APEX))) { dname_remove_label(&vq->qchase.qname, &vq->qchase.qname_len); } } val_mark_indeterminate(vq->chase_reply, ve->anchors, qstate->env->rrset_cache); vq->trust_anchor = anchors_lookup(ve->anchors, vq->qchase.qname, vq->qchase.qname_len, vq->qchase.qclass); if(vq->trust_anchor == NULL) { /*response isn't under a trust anchor, so we cannot validate.*/ vq->chase_reply->security = sec_status_indeterminate; /* go to finished state to cache this result */ vq->state = VAL_FINISHED_STATE; return 1; } /* Determine the signer/lookup name */ val_find_signer(subtype, &vq->qchase, vq->orig_msg->rep, vq->rrset_skip, &vq->signer_name, &vq->signer_len); if(vq->signer_name == NULL) { lookup_name = vq->qchase.qname; lookup_len = vq->qchase.qname_len; log_nametypeclass(VERB_ALGO, "no signer, using", lookup_name, 0, 0); } else { lookup_name = vq->signer_name; lookup_len = vq->signer_len; log_nametypeclass(VERB_ALGO, "signer is", lookup_name, 0, 0); } /* for NXDOMAIN it could be signed by a parent of the trust anchor */ if(subtype == VAL_CLASS_NAMEERROR && vq->signer_name && dname_strict_subdomain_c(vq->trust_anchor->name, lookup_name)){ while(vq->trust_anchor && dname_strict_subdomain_c( vq->trust_anchor->name, lookup_name)) { vq->trust_anchor = vq->trust_anchor->parent; } if(!vq->trust_anchor) { /* unsigned parent denies anchor*/ verbose(VERB_DETAIL, "unsigned parent zone denies" " trust anchor, indeterminate"); vq->chase_reply->security = sec_status_indeterminate; vq->state = VAL_FINISHED_STATE; return 1; } verbose(VERB_ALGO, "trust anchor NXDOMAIN by signed parent"); } if(vq->rrset_skip > 0 || subtype == VAL_CLASS_CNAME || subtype == VAL_CLASS_REFERRAL) { /* extract this part of orig_msg into chase_reply for * the eventual VALIDATE stage */ val_fill_reply(vq->chase_reply, vq->orig_msg->rep, vq->rrset_skip, lookup_name, lookup_len); log_dns_msg("chased extract", &vq->qchase, vq->chase_reply); } vq->key_entry = key_cache_obtain(ve->kcache, lookup_name, lookup_len, vq->qchase.qclass, qstate->region); /* if not key, or if keyentry is *above* the trustanchor, i.e. * the keyentry is based on another (higher) trustanchor */ if(vq->key_entry == NULL || dname_strict_subdomain_c( vq->trust_anchor->name, vq->key_entry->name)) { /* fire off a trust anchor priming query. */ verbose(VERB_ALGO, "prime trust anchor"); if(!prime_trust_anchor(qstate, vq, id, vq->trust_anchor)) return val_error(qstate, id); /* and otherwise, don't continue processing this event. * (it will be reactivated when the priming query returns). */ vq->state = VAL_FINDKEY_STATE; return 0; } else if(key_entry_isnull(vq->key_entry)) { /* response is under a null key, so we cannot validate * However, we do set the status to INSECURE, since it is * essentially proven insecure. */ vq->chase_reply->security = sec_status_insecure; val_mark_insecure(vq->chase_reply, vq->key_entry, qstate->env->rrset_cache); /* go to finished state to cache this result */ vq->state = VAL_FINISHED_STATE; return 1; } /* otherwise, we have our "closest" cached key -- continue * processing in the next state. */ vq->state = VAL_FINDKEY_STATE; return 1; } /** * Process the FINDKEY state. Generally this just calculates the next name * to query and either issues a DS or a DNSKEY query. It will check to see * if the correct key has already been reached, in which case it will * advance the event to the next state. * * @param qstate: query state. * @param vq: validator query state. * @param id: module id. * @return true if the event should be processed further on return, false if * not. */ static int processFindKey(struct module_qstate* qstate, struct val_qstate* vq, int id) { uint8_t* target_key_name, *current_key_name; size_t target_key_len, current_key_len; int strip_lab; log_query_info(VERB_ALGO, "validator: FindKey", &vq->qchase); /* We know that state.key_entry is not a null or bad key -- if it were, * then previous processing should have directed this event to * a different state. */ log_assert(vq->key_entry && !key_entry_isbad(vq->key_entry) && !key_entry_isnull(vq->key_entry)); target_key_name = vq->signer_name; target_key_len = vq->signer_len; if(!target_key_name) { target_key_name = vq->qchase.qname; target_key_len = vq->qchase.qname_len; } current_key_name = vq->key_entry->name; current_key_len = vq->key_entry->namelen; /* If our current key entry matches our target, then we are done. */ if(query_dname_compare(target_key_name, current_key_name) == 0) { vq->state = VAL_VALIDATE_STATE; return 1; } if(vq->empty_DS_name) { current_key_name = vq->empty_DS_name; current_key_len = vq->empty_DS_len; } log_nametypeclass(VERB_ALGO, "current keyname", current_key_name, LDNS_RR_TYPE_DNSKEY, LDNS_RR_CLASS_IN); log_nametypeclass(VERB_ALGO, "target keyname", target_key_name, LDNS_RR_TYPE_DNSKEY, LDNS_RR_CLASS_IN); /* assert we are walking down the DNS tree */ log_assert(dname_subdomain_c(target_key_name, current_key_name)); /* so this value is >= 0 */ strip_lab = dname_count_labels(target_key_name) - dname_count_labels(current_key_name) - 1; log_assert(strip_lab >= 0); verbose(VERB_ALGO, "striplab %d", strip_lab); dname_remove_labels(&target_key_name, &target_key_len, strip_lab); log_nametypeclass(VERB_ALGO, "next keyname", target_key_name, LDNS_RR_TYPE_DNSKEY, LDNS_RR_CLASS_IN); /* The next step is either to query for the next DS, or to query * for the next DNSKEY. */ if(!vq->ds_rrset || query_dname_compare(vq->ds_rrset->rk.dname, target_key_name) != 0) { if(!generate_request(qstate, id, target_key_name, target_key_len, LDNS_RR_TYPE_DS, vq->qchase.qclass)) { log_err("mem error generating DS request"); return val_error(qstate, id); } return 0; } /* Otherwise, it is time to query for the DNSKEY */ if(!generate_request(qstate, id, vq->ds_rrset->rk.dname, vq->ds_rrset->rk.dname_len, LDNS_RR_TYPE_DNSKEY, vq->qchase.qclass)) { log_err("mem error generating DNSKEY request"); return val_error(qstate, id); } return 0; } /** * Process the VALIDATE stage, the init and findkey stages are finished, * and the right keys are available to validate the response. * Or, there are no keys available, in order to invalidate the response. * * After validation, the status is recorded in the message and rrsets, * and finished state is started. * * @param qstate: query state. * @param vq: validator query state. * @param ve: validator shared global environment. * @param id: module id. * @return true if the event should be processed further on return, false if * not. */ static int processValidate(struct module_qstate* qstate, struct val_qstate* vq, struct val_env* ve, int id) { enum val_classification subtype; if(!vq->key_entry) { verbose(VERB_ALGO, "validate: no key entry, failed"); return val_error(qstate, id); } /* This is the default next state. */ vq->state = VAL_FINISHED_STATE; /* signerName being null is the indicator that this response was * unsigned */ if(vq->signer_name == NULL) { log_query_info(VERB_ALGO, "processValidate: state has no " "signer name", &vq->qchase); /* Unsigned responses must be underneath a "null" key entry.*/ if(key_entry_isnull(vq->key_entry)) { verbose(VERB_ALGO, "Unsigned response was proven to " "be validly INSECURE"); vq->chase_reply->security = sec_status_insecure; val_mark_insecure(vq->chase_reply, vq->key_entry, qstate->env->rrset_cache); return 1; } verbose(VERB_DETAIL, "Could not establish validation of " "INSECURE status of unsigned response."); vq->chase_reply->security = sec_status_bogus; return 1; } if(key_entry_isbad(vq->key_entry)) { log_nametypeclass(VERB_DETAIL, "Could not establish a chain " "of trust to keys for", vq->key_entry->name, LDNS_RR_TYPE_DNSKEY, vq->key_entry->key_class); vq->chase_reply->security = sec_status_bogus; return 1; } if(key_entry_isnull(vq->key_entry)) { verbose(VERB_ALGO, "Verified that response is INSECURE"); vq->chase_reply->security = sec_status_insecure; val_mark_insecure(vq->chase_reply, vq->key_entry, qstate->env->rrset_cache); return 1; } /* check signatures in the message; * answer and authority must be valid, additional is only checked. */ if(!validate_msg_signatures(qstate->env, ve, &vq->qchase, vq->chase_reply, vq->key_entry)) { verbose(VERB_DETAIL, "Validate: message contains bad rrsets"); return 1; } subtype = val_classify_response(qstate->query_flags, &vq->qchase, vq->orig_msg->rep, vq->rrset_skip); switch(subtype) { case VAL_CLASS_POSITIVE: verbose(VERB_ALGO, "Validating a positive response"); validate_positive_response(qstate->env, ve, &vq->qchase, vq->chase_reply, vq->key_entry); break; case VAL_CLASS_NODATA: verbose(VERB_ALGO, "Validating a nodata response"); validate_nodata_response(qstate->env, ve, &vq->qchase, vq->chase_reply, vq->key_entry); break; case VAL_CLASS_NAMEERROR: verbose(VERB_ALGO, "Validating a nxdomain response"); validate_nameerror_response(qstate->env, ve, &vq->qchase, vq->chase_reply, vq->key_entry); break; case VAL_CLASS_CNAME: verbose(VERB_ALGO, "Validating a cname response"); validate_cname_response(qstate->env, ve, &vq->qchase, vq->chase_reply, vq->key_entry); break; case VAL_CLASS_CNAMENOANSWER: verbose(VERB_ALGO, "Validating a cname noanswer " "response"); validate_cname_noanswer_response(qstate->env, ve, &vq->qchase, vq->chase_reply, vq->key_entry); break; case VAL_CLASS_REFERRAL: verbose(VERB_ALGO, "Validating a referral response"); validate_referral_response(vq->chase_reply); break; case VAL_CLASS_ANY: verbose(VERB_ALGO, "Validating a positive ANY " "response"); validate_any_response(&vq->qchase, vq->chase_reply); break; default: log_err("validate: unhandled response subtype: %d", subtype); } return 1; } /** * The Finished state. The validation status (good or bad) has been determined. * * @param qstate: query state. * @param vq: validator query state. * @param ve: validator shared global environment. * @param id: module id. * @return true if the event should be processed further on return, false if * not. */ static int processFinished(struct module_qstate* qstate, struct val_qstate* vq, struct val_env* ve, int id) { enum val_classification subtype = val_classify_response( qstate->query_flags, &vq->qchase, vq->orig_msg->rep, vq->rrset_skip); /* store overall validation result in orig_msg */ if(vq->rrset_skip == 0) vq->orig_msg->rep->security = vq->chase_reply->security; else if(vq->rrset_skip < vq->orig_msg->rep->an_numrrsets + vq->orig_msg->rep->ns_numrrsets) { /* ignore sec status of additional section if a referral * type message skips there and * use the lowest security status as end result. */ if(vq->chase_reply->security < vq->orig_msg->rep->security) vq->orig_msg->rep->security = vq->chase_reply->security; } if(subtype == VAL_CLASS_REFERRAL) { /* for a referral, move to next unchecked rrset and check it*/ vq->rrset_skip = val_next_unchecked(vq->orig_msg->rep, vq->rrset_skip); if(vq->rrset_skip < vq->orig_msg->rep->rrset_count) { /* and restart for this rrset */ verbose(VERB_ALGO, "validator: go to next rrset"); vq->chase_reply->security = sec_status_unchecked; vq->state = VAL_INIT_STATE; return 1; } /* referral chase is done */ } if(vq->chase_reply->security != sec_status_bogus && subtype == VAL_CLASS_CNAME) { /* chase the CNAME; process next part of the message */ if(!val_chase_cname(&vq->qchase, vq->orig_msg->rep, &vq->rrset_skip)) { verbose(VERB_ALGO, "validator: failed to chase CNAME"); vq->orig_msg->rep->security = sec_status_bogus; } else { /* restart process for new qchase at rrset_skip */ log_query_info(VERB_ALGO, "validator: chased to", &vq->qchase); vq->chase_reply->security = sec_status_unchecked; vq->state = VAL_INIT_STATE; return 1; } } if(vq->orig_msg->rep->security == sec_status_secure) { /* If the message is secure, check that all rrsets are * secure (i.e. some inserted RRset for CNAME chain with * a different signer name). And drop additional rrsets * that are not secure (if clean-additional option is set) */ /* this may cause the msg to be marked bogus */ val_check_nonsecure(ve, vq->orig_msg->rep); } /* if the result is bogus - set message ttl to bogus ttl to avoid * endless bogus revalidation */ if(vq->orig_msg->rep->security == sec_status_bogus) { vq->orig_msg->rep->ttl = time(0) + ve->bogus_ttl; /* If we are in permissive mode, bogus gets indeterminate */ if(ve->permissive_mode) vq->orig_msg->rep->security = sec_status_indeterminate; } /* store results in cache */ if(qstate->query_flags&BIT_RD) { if(!dns_cache_store(qstate->env, &vq->orig_msg->qinfo, vq->orig_msg->rep, 0)) { log_err("out of memory caching validator results"); } } else { /* for a referral, store the verified RRsets */ if(!dns_cache_store(qstate->env, &vq->orig_msg->qinfo, vq->orig_msg->rep, 1)) { log_err("out of memory caching validator results"); } } qstate->return_rcode = LDNS_RCODE_NOERROR; qstate->return_msg = vq->orig_msg; qstate->ext_state[id] = module_finished; return 0; } /** * Handle validator state. * If a method returns true, the next state is started. If false, then * processing will stop. * @param qstate: query state. * @param vq: validator query state. * @param ve: validator shared global environment. * @param id: module id. */ static void val_handle(struct module_qstate* qstate, struct val_qstate* vq, struct val_env* ve, int id) { int cont = 1; while(cont) { verbose(VERB_ALGO, "val handle processing q with state %s", val_state_to_string(vq->state)); switch(vq->state) { case VAL_INIT_STATE: cont = processInit(qstate, vq, ve, id); break; case VAL_FINDKEY_STATE: cont = processFindKey(qstate, vq, id); break; case VAL_VALIDATE_STATE: cont = processValidate(qstate, vq, ve, id); break; case VAL_FINISHED_STATE: cont = processFinished(qstate, vq, ve, id); break; default: log_warn("validator: invalid state %d", vq->state); cont = 0; break; } } } /** validator operate on a query */ static void val_operate(struct module_qstate* qstate, enum module_ev event, int id, struct outbound_entry* outbound) { struct val_env* ve = (struct val_env*)qstate->env->modinfo[id]; struct val_qstate* vq = (struct val_qstate*)qstate->minfo[id]; verbose(VERB_DETAIL, "validator[module %d] operate: extstate:%s " "event:%s", id, strextstate(qstate->ext_state[id]), strmodulevent(event)); log_query_info(VERB_DETAIL, "validator operate: query", &qstate->qinfo); if(vq && qstate->qinfo.qname != vq->qchase.qname) log_query_info(VERB_DETAIL, "validator operate: chased to", &vq->qchase); (void)outbound; if(event == module_event_new || (event == module_event_pass && vq == NULL)) { /* pass request to next module, to get it */ verbose(VERB_ALGO, "validator: pass to next module"); qstate->ext_state[id] = module_wait_module; return; } if(event == module_event_moddone) { /* check if validation is needed */ verbose(VERB_ALGO, "validator: nextmodule returned"); if(!needs_validation(qstate, qstate->return_rcode, qstate->return_msg)) { /* no need to validate this */ qstate->ext_state[id] = module_finished; return; } /* create state to start validation */ qstate->ext_state[id] = module_error; /* override this */ if(!vq) { vq = val_new(qstate, id); if(!vq) { log_err("validator: malloc failure"); qstate->ext_state[id] = module_error; return; } } val_handle(qstate, vq, ve, id); return; } if(event == module_event_pass) { qstate->ext_state[id] = module_error; /* override this */ /* continue processing, since val_env exists */ val_handle(qstate, vq, ve, id); return; } log_err("validator: bad event %s", strmodulevent(event)); qstate->ext_state[id] = module_error; return; } /** * Evaluate the response to a priming request. * * @param rcode: rcode return value. * @param msg: message return value (allocated in a the wrong region). * @param ta: trust anchor. * @param qstate: qstate that needs key. * @param id: module id. * @return new key entry or NULL on allocation failure. * The key entry will either contain a validated DNSKEY rrset, or * represent a Null key (query failed, but validation did not), or a * Bad key (validation failed). */ static struct key_entry_key* primeResponseToKE(int rcode, struct dns_msg* msg, struct trust_anchor* ta, struct module_qstate* qstate, int id) { struct val_env* ve = (struct val_env*)qstate->env->modinfo[id]; struct ub_packed_rrset_key* dnskey_rrset = NULL; struct key_entry_key* kkey = NULL; enum sec_status sec = sec_status_unchecked; if(rcode == LDNS_RCODE_NOERROR) { dnskey_rrset = reply_find_rrset_section_an(msg->rep, ta->name, ta->namelen, LDNS_RR_TYPE_DNSKEY, ta->dclass); } if(!dnskey_rrset) { log_query_info(VERB_OPS, "failed to prime trust anchor -- " "could not fetch DNSKEY rrset", &msg->qinfo); kkey = key_entry_create_null(qstate->region, ta->name, ta->namelen, ta->dclass, NULL_KEY_TTL); if(!kkey) { log_err("out of memory: allocate null prime key"); return NULL; } key_cache_insert(ve->kcache, kkey); return kkey; } /* attempt to verify with trust anchor DS and DNSKEY */ if(ta->ds_rrset) { kkey = val_verify_new_DNSKEYs(qstate->region, qstate->env, ve, dnskey_rrset, ta->ds_rrset); if(!kkey) { log_err("out of memory: verifying prime DS"); return NULL; } if(key_entry_isgood(kkey)) sec = sec_status_secure; else sec = sec_status_bogus; log_info("priming DS result %s", sec_status_to_string(sec)); } if(sec != sec_status_secure && ta->dnskey_rrset) { sec = val_verify_rrset(qstate->env, ve, dnskey_rrset, ta->dnskey_rrset); if(sec == sec_status_secure) { kkey = key_entry_create_rrset(qstate->region, ta->name, ta->namelen, ta->dclass, dnskey_rrset); if(!kkey) { log_err("out of memory: allocate primed key"); return NULL; } } } if(sec != sec_status_secure) { log_query_info(VERB_OPS, "failed to prime trust anchor -- " "could not fetch secure DNSKEY rrset", &msg->qinfo); /* NOTE: in this case, we should probably reject the trust * anchor for longer, perhaps forever. */ kkey = key_entry_create_null(qstate->region, ta->name, ta->namelen, ta->dclass, NULL_KEY_TTL); if(!kkey) { log_err("out of memory: allocate null prime key"); return NULL; } key_cache_insert(ve->kcache, kkey); return kkey; } log_query_info(VERB_ALGO, "Successfully primed trust anchor", &msg->qinfo); /* store the freshly primed entry in the cache */ key_cache_insert(ve->kcache, kkey); return kkey; } /** * In inform supers, with the resulting message and rcode and the current * keyset in the super state, validate the DS response, returning a KeyEntry. * * @param qstate: query state that is validating and asked for a DS. * @param vq: validator query state * @param id: module id. * @param rcode: rcode result value. * @param msg: result message (if rcode is OK). * @param qinfo: from the sub query state, query info. * @param ke: the key entry to return. It returns * bad if the DS response fails to validate, null if the * DS response indicated an end to secure space, good if the DS * validated. It returns null if the DS response indicated that the * request wasn't a delegation point. * @return 0 on servfail error (malloc failure). */ static int ds_response_to_ke(struct module_qstate* qstate, struct val_qstate* vq, int id, int rcode, struct dns_msg* msg, struct query_info* qinfo, struct key_entry_key** ke) { struct val_env* ve = (struct val_env*)qstate->env->modinfo[id]; enum val_classification subtype; if(rcode != LDNS_RCODE_NOERROR) { /* errors here pretty much break validation */ verbose(VERB_DETAIL, "DS response was error, thus bogus"); goto return_bogus; } subtype = val_classify_response(BIT_RD, qinfo, msg->rep, 0); if(subtype == VAL_CLASS_POSITIVE) { struct ub_packed_rrset_key* ds; enum sec_status sec; ds = reply_find_answer_rrset(qinfo, msg->rep); /* If there was no DS rrset, then we have mis-classified * this message. */ if(!ds) { log_warn("internal error: POSITIVE DS response was " "missing DS."); goto return_bogus; } /* Verify only returns BOGUS or SECURE. If the rrset is * bogus, then we are done. */ sec = val_verify_rrset_entry(qstate->env, ve, ds, vq->key_entry); if(sec != sec_status_secure) { verbose(VERB_DETAIL, "DS rrset in DS response did " "not verify"); goto return_bogus; } /* If the DS rrset validates, we still have to make sure * that they are usable. */ if(!val_dsset_isusable(ds)) { /* If they aren't usable, then we treat it like * there was no DS. */ *ke = key_entry_create_null(qstate->region, qinfo->qname, qinfo->qname_len, qinfo->qclass, ub_packed_rrset_ttl(ds)); return (*ke) != NULL; } /* Otherwise, we return the positive response. */ log_query_info(VERB_ALGO, "DS rrset was good.", qinfo); *ke = key_entry_create_rrset(qstate->region, qinfo->qname, qinfo->qname_len, qinfo->qclass, ds); return (*ke) != NULL; } else if(subtype == VAL_CLASS_NODATA) { /* NODATA means that the qname exists, but that there was * no DS. This is a pretty normal case. */ uint32_t proof_ttl = 0; /* Try to prove absence of the DS with NSEC */ enum sec_status sec = val_nsec_prove_nodata_dsreply( qstate->env, ve, qinfo, msg->rep, vq->key_entry, &proof_ttl); switch(sec) { case sec_status_secure: verbose(VERB_ALGO, "NSEC RRset for the " "referral proved no DS."); *ke = key_entry_create_null(qstate->region, qinfo->qname, qinfo->qname_len, qinfo->qclass, proof_ttl); return (*ke) != NULL; case sec_status_insecure: verbose(VERB_ALGO, "NSEC RRset for the " "referral proved not a delegation point"); *ke = NULL; return 1; case sec_status_bogus: verbose(VERB_DETAIL, "NSEC RRset for the " "referral did not prove no DS."); goto return_bogus; case sec_status_unchecked: default: /* NSEC proof did not work, try next */ break; } sec = nsec3_prove_nods(qstate->env, ve, msg->rep->rrsets + msg->rep->an_numrrsets, msg->rep->ns_numrrsets, qinfo, vq->key_entry); switch(sec) { case sec_status_secure: verbose(VERB_ALGO, "NSEC3s for the " "referral proved no DS."); *ke = key_entry_create_null(qstate->region, qinfo->qname, qinfo->qname_len, qinfo->qclass, proof_ttl); return (*ke) != NULL; case sec_status_indeterminate: verbose(VERB_ALGO, "NSEC3s for the " "referral proved no delegation"); *ke = NULL; return 1; case sec_status_bogus: verbose(VERB_DETAIL, "NSEC3s for the " "referral did not prove no DS."); goto return_bogus; case sec_status_insecure: case sec_status_unchecked: default: /* NSEC3 proof did not work */ break; } /* Apparently, no available NSEC/NSEC3 proved NODATA, so * this is BOGUS. */ verbose(VERB_DETAIL, "DS ran out of options, so return bogus"); goto return_bogus; } else if(subtype == VAL_CLASS_NAMEERROR) { verbose(VERB_DETAIL, "DS response was NAMEERROR, thus bogus."); goto return_bogus; } else { verbose(VERB_DETAIL, "Encountered an unhandled type of " "DS response, thus bogus."); return_bogus: *ke = key_entry_create_bad(qstate->region, qinfo->qname, qinfo->qname_len, qinfo->qclass); return (*ke) != NULL; } /* unreachable */ log_assert(0); return 0; } /** * Process DS response. Called from inform_supers. * Because it is in inform_supers, the mesh itself is busy doing callbacks * for a state that is to be deleted soon; don't touch the mesh; instead * set a state in the super, as the super will be reactivated soon. * Perform processing to determine what state to set in the super. * * @param qstate: query state that is validating and asked for a DS. * @param vq: validator query state * @param id: module id. * @param rcode: rcode result value. * @param msg: result message (if rcode is OK). * @param qinfo: from the sub query state, query info. */ static void process_ds_response(struct module_qstate* qstate, struct val_qstate* vq, int id, int rcode, struct dns_msg* msg, struct query_info* qinfo) { struct key_entry_key* dske = NULL; if(!ds_response_to_ke(qstate, vq, id, rcode, msg, qinfo, &dske)) { log_err("malloc failure in process_ds_response"); vq->key_entry = NULL; /* make it error */ vq->state = VAL_VALIDATE_STATE; return; } if(dske == NULL) { vq->empty_DS_name = qinfo->qname; vq->empty_DS_len = qinfo->qname_len; /* ds response indicated that we aren't on a delegation point. * Keep the forState.state on FINDKEY. */ } else if(key_entry_isgood(dske)) { vq->ds_rrset = key_entry_get_rrset(dske, qstate->region); if(!vq->ds_rrset) { log_err("malloc failure in process DS"); vq->key_entry = NULL; /* make it error */ vq->state = VAL_VALIDATE_STATE; return; } /* Keep the forState.state on FINDKEY. */ } else { /* NOTE: the reason for the DS to be not good (that is, * either bad or null) should have been logged by * dsResponseToKE. */ vq->key_entry = dske; /* The FINDKEY phase has ended, so move on. */ vq->state = VAL_VALIDATE_STATE; } } /** * Process DNSKEY response. Called from inform_supers. * Sets the key entry in the state. * Because it is in inform_supers, the mesh itself is busy doing callbacks * for a state that is to be deleted soon; don't touch the mesh; instead * set a state in the super, as the super will be reactivated soon. * Perform processing to determine what state to set in the super. * * @param qstate: query state that is validating and asked for a DNSKEY. * @param vq: validator query state * @param id: module id. * @param rcode: rcode result value. * @param msg: result message (if rcode is OK). * @param qinfo: from the sub query state, query info. */ static void process_dnskey_response(struct module_qstate* qstate, struct val_qstate* vq, int id, int rcode, struct dns_msg* msg, struct query_info* qinfo) { struct val_env* ve = (struct val_env*)qstate->env->modinfo[id]; struct ub_packed_rrset_key* dnskey = NULL; if(rcode == LDNS_RCODE_NOERROR) dnskey = reply_find_answer_rrset(qinfo, msg->rep); if(dnskey == NULL) { /* bad response */ verbose(VERB_DETAIL, "Missing DNSKEY RRset in response to " "DNSKEY query."); vq->key_entry = key_entry_create_bad(qstate->region, qinfo->qname, qinfo->qname_len, qinfo->qclass); if(!vq->key_entry) { log_err("alloc failure in missing dnskey response"); /* key_entry is NULL for failure in Validate */ } vq->state = VAL_VALIDATE_STATE; return; } if(!vq->ds_rrset) { log_err("internal error: no DS rrset for new DNSKEY response"); vq->key_entry = NULL; vq->state = VAL_VALIDATE_STATE; return; } vq->key_entry = val_verify_new_DNSKEYs(qstate->region, qstate->env, ve, dnskey, vq->ds_rrset); if(!vq->key_entry) { log_err("out of memory in verify new DNSKEYs"); vq->state = VAL_VALIDATE_STATE; return; } /* If the key entry isBad or isNull, then we can move on to the next * state. */ if(!key_entry_isgood(vq->key_entry)) { if(key_entry_isbad(vq->key_entry)) verbose(VERB_DETAIL, "Did not match a DS to a DNSKEY, " "thus bogus."); vq->state = VAL_VALIDATE_STATE; return; } /* The DNSKEY validated, so cache it as a trusted key rrset. */ key_cache_insert(ve->kcache, vq->key_entry); /* If good, we stay in the FINDKEY state. */ } /** * Process prime response * Sets the key entry in the state. * * @param qstate: query state that is validating and primed a trust anchor. * @param vq: validator query state * @param id: module id. * @param rcode: rcode result value. * @param msg: result message (if rcode is OK). */ static void process_prime_response(struct module_qstate* qstate, struct val_qstate* vq, int id, int rcode, struct dns_msg* msg) { /* Fetch and validate the keyEntry that corresponds to the * current trust anchor. */ vq->key_entry = primeResponseToKE(rcode, msg, vq->trust_anchor, qstate, id); /* If the result of the prime is a null key, skip the FINDKEY state.*/ if(!vq->key_entry || key_entry_isnull(vq->key_entry)) { vq->state = VAL_VALIDATE_STATE; } /* the qstate will be reactivated after inform_super is done */ } /** * inform validator super. * * @param qstate: query state that finished. * @param id: module id. * @param super: the qstate to inform. */ static void val_inform_super(struct module_qstate* qstate, int id, struct module_qstate* super) { struct val_qstate* vq = (struct val_qstate*)super->minfo[id]; log_query_info(VERB_ALGO, "validator: inform_super, sub is", &qstate->qinfo); log_query_info(VERB_ALGO, "super is", &super->qinfo); if(!vq) { verbose(VERB_ALGO, "super: has no validator state"); return; } if(vq->wait_prime_ta) { vq->wait_prime_ta = 0; process_prime_response(super, vq, id, qstate->return_rcode, qstate->return_msg); return; } if(qstate->qinfo.qtype == LDNS_RR_TYPE_DS) { process_ds_response(super, vq, id, qstate->return_rcode, qstate->return_msg, &qstate->qinfo); return; } else if(qstate->qinfo.qtype == LDNS_RR_TYPE_DNSKEY) { process_dnskey_response(super, vq, id, qstate->return_rcode, qstate->return_msg, &qstate->qinfo); return; } log_err("internal error in validator: no inform_supers possible"); } /** validator cleanup query state */ static void val_clear(struct module_qstate* qstate, int id) { if(!qstate) return; /* everything is allocated in the region, so assign NULL */ qstate->minfo[id] = NULL; } /** * Debug helper routine that assists worker in determining memory in * use. * @param env: module environment * @param id: module id. * @return memory in use in bytes. */ static size_t val_get_mem(struct module_env* env, int id) { struct val_env* ve = (struct val_env*)env->modinfo[id]; if(!ve) return 0; return sizeof(*ve) + key_cache_get_mem(ve->kcache) + anchors_get_mem(ve->anchors) + sizeof(size_t)*2*ve->nsec3_keyiter_count; } /** * The validator function block */ static struct module_func_block val_block = { "validator", &val_init, &val_deinit, &val_operate, &val_inform_super, &val_clear, &val_get_mem }; struct module_func_block* val_get_funcblock() { return &val_block; } const char* val_state_to_string(enum val_state state) { switch(state) { case VAL_INIT_STATE: return "VAL_INIT_STATE"; case VAL_FINDKEY_STATE: return "VAL_FINDKEY_STATE"; case VAL_VALIDATE_STATE: return "VAL_VALIDATE_STATE"; case VAL_FINISHED_STATE: return "VAL_FINISHED_STATE"; } return "UNKNOWN VALIDATOR STATE"; }