/* * validator/val_utils.h - validator utility functions. * * Copyright (c) 2007, NLnet Labs. All rights reserved. * * This software is open source. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * Neither the name of the NLNET LABS nor the names of its contributors may * be used to endorse or promote products derived from this software without * specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /** * \file * * This file contains helper functions for the validator module. */ #ifndef VALIDATOR_VAL_UTILS_H #define VALIDATOR_VAL_UTILS_H #include "util/data/packed_rrset.h" struct query_info; struct reply_info; struct val_env; struct module_env; struct ub_packed_rrset_key; struct key_entry_key; struct regional; struct val_anchors; struct rrset_cache; struct sock_list; /** * Response classifications for the validator. The different types of proofs. */ enum val_classification { /** Not subtyped yet. */ VAL_CLASS_UNTYPED = 0, /** Not a recognized subtype. */ VAL_CLASS_UNKNOWN, /** A positive, direct, response */ VAL_CLASS_POSITIVE, /** A positive response, with a CNAME/DNAME chain. */ VAL_CLASS_CNAME, /** A NOERROR/NODATA response. */ VAL_CLASS_NODATA, /** A NXDOMAIN response. */ VAL_CLASS_NAMEERROR, /** A CNAME/DNAME chain, and the offset is at the end of it, * but there is no answer here, it can be NAMERROR or NODATA. */ VAL_CLASS_CNAMENOANSWER, /** A referral, from cache with a nonRD query. */ VAL_CLASS_REFERRAL, /** A response to a qtype=ANY query. */ VAL_CLASS_ANY }; /** * Given a response, classify ANSWER responses into a subtype. * @param query_flags: query flags for the original query. * @param origqinf: query info. The original query name. * @param qinf: query info. The chased query name. * @param rep: response. The original response. * @param skip: offset into the original response answer section. * @return A subtype, all values possible except UNTYPED . * Once CNAME type is returned you can increase skip. * Then, another CNAME type, CNAME_NOANSWER or POSITIVE are possible. */ enum val_classification val_classify_response(uint16_t query_flags, struct query_info* origqinf, struct query_info* qinf, struct reply_info* rep, size_t skip); /** * Given a response, determine the name of the "signer". This is primarily * to determine if the response is, in fact, signed at all, and, if so, what * is the name of the most pertinent keyset. * * @param subtype: the type from classify. * @param qinf: query, the chased query name. * @param rep: response to that, original response. * @param cname_skip: how many answer rrsets have been skipped due to CNAME * chains being chased around. * @param signer_name: signer name, if the response is signed * (even partially), or null if the response isn't signed. * @param signer_len: length of signer_name of 0 if signer_name is NULL. */ void val_find_signer(enum val_classification subtype, struct query_info* qinf, struct reply_info* rep, size_t cname_skip, uint8_t** signer_name, size_t* signer_len); /** * Verify RRset with keys * @param env: module environment (scratch buffer) * @param ve: validator environment (verification settings) * @param rrset: what to verify * @param keys: dnskey rrset to verify with. * @param sigalg: if nonNULL provide downgrade protection otherwise one * algorithm is enough. Algo list is constructed in here. * @param reason: reason of failure. Fixed string or alloced in scratch. * @return security status of verification. */ enum sec_status val_verify_rrset(struct module_env* env, struct val_env* ve, struct ub_packed_rrset_key* rrset, struct ub_packed_rrset_key* keys, uint8_t* sigalg, char** reason); /** * Verify RRset with keys from a keyset. * @param env: module environment (scratch buffer) * @param ve: validator environment (verification settings) * @param rrset: what to verify * @param kkey: key_entry to verify with. * @param reason: reason of failure. Fixed string or alloced in scratch. * @return security status of verification. */ enum sec_status val_verify_rrset_entry(struct module_env* env, struct val_env* ve, struct ub_packed_rrset_key* rrset, struct key_entry_key* kkey, char** reason); /** * Verify DNSKEYs with DS rrset. Like val_verify_new_DNSKEYs but * returns a sec_status instead of a key_entry. * @param env: module environment (scratch buffer) * @param ve: validator environment (verification settings) * @param dnskey_rrset: DNSKEY rrset to verify * @param ds_rrset: DS rrset to verify with. * @param sigalg: if nonNULL provide downgrade protection otherwise one * algorithm is enough. The list of signalled algorithms is returned, * must have enough space for ALGO_NEEDS_MAX+1. * @param reason: reason of failure. Fixed string or alloced in scratch. * @return: sec_status_secure if a DS matches. * sec_status_insecure if end of trust (i.e., unknown algorithms). * sec_status_bogus if it fails. */ enum sec_status val_verify_DNSKEY_with_DS(struct module_env* env, struct val_env* ve, struct ub_packed_rrset_key* dnskey_rrset, struct ub_packed_rrset_key* ds_rrset, uint8_t* sigalg, char** reason); /** * Verify DNSKEYs with DS and DNSKEY rrset. Like val_verify_DNSKEY_with_DS * but for a trust anchor. * @param env: module environment (scratch buffer) * @param ve: validator environment (verification settings) * @param dnskey_rrset: DNSKEY rrset to verify * @param ta_ds: DS rrset to verify with. * @param ta_dnskey: DNSKEY rrset to verify with. * @param sigalg: if nonNULL provide downgrade protection otherwise one * algorithm is enough. The list of signalled algorithms is returned, * must have enough space for ALGO_NEEDS_MAX+1. * @param reason: reason of failure. Fixed string or alloced in scratch. * @return: sec_status_secure if a DS matches. * sec_status_insecure if end of trust (i.e., unknown algorithms). * sec_status_bogus if it fails. */ enum sec_status val_verify_DNSKEY_with_TA(struct module_env* env, struct val_env* ve, struct ub_packed_rrset_key* dnskey_rrset, struct ub_packed_rrset_key* ta_ds, struct ub_packed_rrset_key* ta_dnskey, uint8_t* sigalg, char** reason); /** * Verify new DNSKEYs with DS rrset. The DS contains hash values that should * match the DNSKEY keys. * match the DS to a DNSKEY and verify the DNSKEY rrset with that key. * * @param region: where to allocate key entry result. * @param env: module environment (scratch buffer) * @param ve: validator environment (verification settings) * @param dnskey_rrset: DNSKEY rrset to verify * @param ds_rrset: DS rrset to verify with. * @param downprot: if true provide downgrade protection otherwise one * algorithm is enough. * @param reason: reason of failure. Fixed string or alloced in scratch. * @return a KeyEntry. This will either contain the now trusted * dnskey_rrset, a "null" key entry indicating that this DS * rrset/DNSKEY pair indicate an secure end to the island of trust * (i.e., unknown algorithms), or a "bad" KeyEntry if the dnskey * rrset fails to verify. Note that the "null" response should * generally only occur in a private algorithm scenario: normally * this sort of thing is checked before fetching the matching DNSKEY * rrset. * if downprot is set, a key entry with an algo list is made. */ struct key_entry_key* val_verify_new_DNSKEYs(struct regional* region, struct module_env* env, struct val_env* ve, struct ub_packed_rrset_key* dnskey_rrset, struct ub_packed_rrset_key* ds_rrset, int downprot, char** reason); /** * Verify rrset with trust anchor: DS and DNSKEY rrset. * * @param region: where to allocate key entry result. * @param env: module environment (scratch buffer) * @param ve: validator environment (verification settings) * @param dnskey_rrset: DNSKEY rrset to verify * @param ta_ds_rrset: DS rrset to verify with. * @param ta_dnskey_rrset: the DNSKEY rrset to verify with. * @param downprot: if true provide downgrade protection otherwise one * algorithm is enough. * @param reason: reason of failure. Fixed string or alloced in scratch. * @return a KeyEntry. This will either contain the now trusted * dnskey_rrset, a "null" key entry indicating that this DS * rrset/DNSKEY pair indicate an secure end to the island of trust * (i.e., unknown algorithms), or a "bad" KeyEntry if the dnskey * rrset fails to verify. Note that the "null" response should * generally only occur in a private algorithm scenario: normally * this sort of thing is checked before fetching the matching DNSKEY * rrset. * if downprot is set, a key entry with an algo list is made. */ struct key_entry_key* val_verify_new_DNSKEYs_with_ta(struct regional* region, struct module_env* env, struct val_env* ve, struct ub_packed_rrset_key* dnskey_rrset, struct ub_packed_rrset_key* ta_ds_rrset, struct ub_packed_rrset_key* ta_dnskey_rrset, int downprot, char** reason); /** * Determine if DS rrset is usable for validator or not. * Returns true if the algorithms for key and DShash are supported, * for at least one RR. * * @param ds_rrset: the newly received DS rrset. * @return true or false if not usable. */ int val_dsset_isusable(struct ub_packed_rrset_key* ds_rrset); /** * Determine by looking at a signed RRset whether or not the RRset name was * the result of a wildcard expansion. If so, return the name of the * generating wildcard. * * @param rrset The rrset to chedck. * @param wc: the wildcard name, if the rrset was synthesized from a wildcard. * unchanged if not. The wildcard name, without "*." in front, is * returned. This is a pointer into the rrset owner name. * @return false if the signatures are inconsistent in indicating the * wildcard status; possible spoofing of wildcard response for other * responses is being tried. We lost the status which rrsig was verified * after the verification routine finished, so we simply check if * the signatures are consistent; inserting a fake signature is a denial * of service; but in that you could also have removed the real * signature anyway. */ int val_rrset_wildcard(struct ub_packed_rrset_key* rrset, uint8_t** wc); /** * Chase the cname to the next query name. * @param qchase: the current query name, updated to next target. * @param rep: original message reply to look at CNAMEs. * @param cname_skip: the skip into the answer section. Updated to skip * DNAME and CNAME to the next part of the answer. * @return false on error (bad rdata). */ int val_chase_cname(struct query_info* qchase, struct reply_info* rep, size_t* cname_skip); /** * Fill up the chased reply with the content from the original reply; * as pointers to those rrsets. Select the part after the cname_skip into * the answer section, NS and AR sections that are signed with same signer. * * @param chase: chased reply, filled up. * @param orig: original reply. * @param cname_skip: which part of the answer section to skip. * The skipped part contains CNAME(and DNAME)s that have been chased. * @param name: the signer name to look for. * @param len: length of name. * @param signer: signer name or NULL if an unsigned RRset is considered. * If NULL, rrsets with the lookup name are copied over. */ void val_fill_reply(struct reply_info* chase, struct reply_info* orig, size_t cname_skip, uint8_t* name, size_t len, uint8_t* signer); /** * Remove all unsigned or non-secure status rrsets from NS and AR sections. * So that unsigned data does not get let through to clients, when we have * found the data to be secure. * * @param ve: validator environment with cleaning options. * @param rep: reply to dump all nonsecure stuff out of. */ void val_check_nonsecure(struct val_env* ve, struct reply_info* rep); /** * Mark all unchecked rrset entries not below a trust anchor as indeterminate. * Only security==unchecked rrsets are updated. * @param rep: the reply with rrsets. * @param anchors: the trust anchors. * @param r: rrset cache to store updated security status into. * @param env: module environment */ void val_mark_indeterminate(struct reply_info* rep, struct val_anchors* anchors, struct rrset_cache* r, struct module_env* env); /** * Mark all unchecked rrset entries below a NULL key entry as insecure. * Only security==unchecked rrsets are updated. * @param rep: the reply with rrsets. * @param kname: end of secure space name. * @param r: rrset cache to store updated security status into. * @param env: module environment */ void val_mark_insecure(struct reply_info* rep, uint8_t* kname, struct rrset_cache* r, struct module_env* env); /** * Find next unchecked rrset position, return it for skip. * @param rep: the original reply to look into. * @param skip: the skip now. * @return new skip, which may be at the rep->rrset_count position to signal * there are no unchecked items. */ size_t val_next_unchecked(struct reply_info* rep, size_t skip); /** * Find the signer name for an RRset. * @param rrset: the rrset. * @param sname: signer name is returned or NULL if not signed. * @param slen: length of sname (or 0). */ void val_find_rrset_signer(struct ub_packed_rrset_key* rrset, uint8_t** sname, size_t* slen); /** * Get string to denote the classification result. * @param subtype: from classification function. * @return static string to describe the classification. */ const char* val_classification_to_string(enum val_classification subtype); /** * Add existing list to blacklist. * @param blacklist: the blacklist with result * @param region: the region where blacklist is allocated. * Allocation failures are logged. * @param origin: origin list to add, if NULL, a cache-entry is added to * the blacklist to stop cache from being used. * @param cross: if true this is a cross-qstate copy, and the 'origin' * list is not allocated in the same region as the blacklist. */ void val_blacklist(struct sock_list** blacklist, struct regional* region, struct sock_list* origin, int cross); /** * check if has dnssec info, and if it has signed nsecs. gives error reason. * @param rep: reply to check. * @param reason: returned on fail. * @return false if message has no signed nsecs. Can not prove negatives. */ int val_has_signed_nsecs(struct reply_info* rep, char** reason); /** * Return algo number for favorite (best) algorithm that we support in DS. * @param ds_rrset: the DSes in this rrset are inspected and best algo chosen. * @return algo number or 0 if none supported. 0 is unused as algo number. */ int val_favorite_ds_algo(struct ub_packed_rrset_key* ds_rrset); /** * Find DS denial message in cache. Saves new qstate allocation and allows * the validator to use partial content which is not enough to construct a * message for network (or user) consumption. Without SOA for example, * which is a common occurence in the unbound code since the referrals contain * NSEC/NSEC3 rrs without the SOA element, thus do not allow synthesis of a * full negative reply, but do allow synthesis of sufficient proof. * @param env: query env with caches and time. * @param nm: name of DS record sought. * @param nmlen: length of name. * @param c: class of DS RR. * @param region: where to allocate result. * @param topname: name of the key that is currently in use, that will get * used to validate the result, and thus no higher entries from the * negative cache need to be examined. * @return a dns_msg on success. NULL on failure. */ struct dns_msg* val_find_DS(struct module_env* env, uint8_t* nm, size_t nmlen, uint16_t c, struct regional* region, uint8_t* topname); #endif /* VALIDATOR_VAL_UTILS_H */