/*
* 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 rrset with index from reply, from the authority section.
* @param rep: reply to remove it from.
* @param index: rrset to remove, must be in the authority section.
*/
void val_reply_remove_auth(struct reply_info* rep, size_t index);
/**
* 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 occurrence 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 */
