/*
* validator/val_neg.c - validator aggressive negative caching functions.
*
* Copyright (c) 2008, 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 helper functions for the validator module.
* The functions help with aggressive negative caching.
* This creates new denials of existance, and proofs for absence of types
* from cached NSEC records.
*/
#include "config.h"
#ifdef HAVE_OPENSSL_SSL_H
#include "openssl/ssl.h"
#endif
#include "validator/val_neg.h"
#include "validator/val_nsec.h"
#include "validator/val_nsec3.h"
#include "validator/val_utils.h"
#include "util/data/dname.h"
#include "util/data/msgreply.h"
#include "util/log.h"
#include "util/net_help.h"
#include "util/config_file.h"
#include "services/cache/rrset.h"
#include "services/cache/dns.h"
int val_neg_data_compare(const void* a, const void* b)
{
struct val_neg_data* x = (struct val_neg_data*)a;
struct val_neg_data* y = (struct val_neg_data*)b;
int m;
return dname_canon_lab_cmp(x->name, x->labs, y->name, y->labs, &m);
}
int val_neg_zone_compare(const void* a, const void* b)
{
struct val_neg_zone* x = (struct val_neg_zone*)a;
struct val_neg_zone* y = (struct val_neg_zone*)b;
int m;
if(x->dclass != y->dclass) {
if(x->dclass < y->dclass)
return -1;
return 1;
}
return dname_canon_lab_cmp(x->name, x->labs, y->name, y->labs, &m);
}
struct val_neg_cache* val_neg_create(struct config_file* cfg, size_t maxiter)
{
struct val_neg_cache* neg = (struct val_neg_cache*)calloc(1,
sizeof(*neg));
if(!neg) {
log_err("Could not create neg cache: out of memory");
return NULL;
}
neg->nsec3_max_iter = maxiter;
neg->max = 1024*1024; /* 1 M is thousands of entries */
if(cfg) neg->max = cfg->neg_cache_size;
rbtree_init(&neg->tree, &val_neg_zone_compare);
lock_basic_init(&neg->lock);
lock_protect(&neg->lock, neg, sizeof(*neg));
return neg;
}
size_t val_neg_get_mem(struct val_neg_cache* neg)
{
size_t result;
lock_basic_lock(&neg->lock);
result = sizeof(*neg) + neg->use;
lock_basic_unlock(&neg->lock);
return result;
}
/** clear datas on cache deletion */
static void
neg_clear_datas(rbnode_t* n, void* ATTR_UNUSED(arg))
{
struct val_neg_data* d = (struct val_neg_data*)n;
free(d->name);
free(d);
}
/** clear zones on cache deletion */
static void
neg_clear_zones(rbnode_t* n, void* ATTR_UNUSED(arg))
{
struct val_neg_zone* z = (struct val_neg_zone*)n;
/* delete all the rrset entries in the tree */
traverse_postorder(&z->tree, &neg_clear_datas, NULL);
free(z->nsec3_salt);
free(z->name);
free(z);
}
void neg_cache_delete(struct val_neg_cache* neg)
{
if(!neg) return;
lock_basic_destroy(&neg->lock);
/* delete all the zones in the tree */
traverse_postorder(&neg->tree, &neg_clear_zones, NULL);
free(neg);
}
/**
* Put data element at the front of the LRU list.
* @param neg: negative cache with LRU start and end.
* @param data: this data is fronted.
*/
static void neg_lru_front(struct val_neg_cache* neg,
struct val_neg_data* data)
{
data->prev = NULL;
data->next = neg->first;
if(!neg->first)
neg->last = data;
else neg->first->prev = data;
neg->first = data;
}
/**
* Remove data element from LRU list.
* @param neg: negative cache with LRU start and end.
* @param data: this data is removed from the list.
*/
static void neg_lru_remove(struct val_neg_cache* neg,
struct val_neg_data* data)
{
if(data->prev)
data->prev->next = data->next;
else neg->first = data->next;
if(data->next)
data->next->prev = data->prev;
else neg->last = data->prev;
}
/**
* Touch LRU for data element, put it at the start of the LRU list.
* @param neg: negative cache with LRU start and end.
* @param data: this data is used.
*/
static void neg_lru_touch(struct val_neg_cache* neg,
struct val_neg_data* data)
{
if(data == neg->first)
return; /* nothing to do */
/* remove from current lru position */
neg_lru_remove(neg, data);
/* add at front */
neg_lru_front(neg, data);
}
/**
* Delete a zone element from the negative cache.
* May delete other zone elements to keep tree coherent, or
* only mark the element as 'not in use'.
* @param neg: negative cache.
* @param z: zone element to delete.
*/
static void neg_delete_zone(struct val_neg_cache* neg, struct val_neg_zone* z)
{
struct val_neg_zone* p, *np;
if(!z) return;
log_assert(z->in_use);
log_assert(z->count > 0);
z->in_use = 0;
/* go up the tree and reduce counts */
p = z;
while(p) {
log_assert(p->count > 0);
p->count --;
p = p->parent;
}
/* remove zones with zero count */
p = z;
while(p && p->count == 0) {
np = p->parent;
(void)rbtree_delete(&neg->tree, &p->node);
neg->use -= p->len + sizeof(*p);
free(p->nsec3_salt);
free(p->name);
free(p);
p = np;
}
}
void neg_delete_data(struct val_neg_cache* neg, struct val_neg_data* el)
{
struct val_neg_zone* z;
struct val_neg_data* p, *np;
if(!el) return;
z = el->zone;
log_assert(el->in_use);
log_assert(el->count > 0);
el->in_use = 0;
/* remove it from the lru list */
neg_lru_remove(neg, el);
/* go up the tree and reduce counts */
p = el;
while(p) {
log_assert(p->count > 0);
p->count --;
p = p->parent;
}
/* delete 0 count items from tree */
p = el;
while(p && p->count == 0) {
np = p->parent;
(void)rbtree_delete(&z->tree, &p->node);
neg->use -= p->len + sizeof(*p);
free(p->name);
free(p);
p = np;
}
/* check if the zone is now unused */
if(z->tree.count == 0) {
neg_delete_zone(neg, z);
}
}
/**
* Create more space in negative cache
* The oldest elements are deleted until enough space is present.
* Empty zones are deleted.
* @param neg: negative cache.
* @param need: how many bytes are needed.
*/
static void neg_make_space(struct val_neg_cache* neg, size_t need)
{
/* delete elements until enough space or its empty */
while(neg->last && neg->max < neg->use + need) {
neg_delete_data(neg, neg->last);
}
}
struct val_neg_zone* neg_find_zone(struct val_neg_cache* neg,
uint8_t* nm, size_t len, uint16_t dclass)
{
struct val_neg_zone lookfor;
struct val_neg_zone* result;
lookfor.node.key = &lookfor;
lookfor.name = nm;
lookfor.len = len;
lookfor.labs = dname_count_labels(lookfor.name);
lookfor.dclass = dclass;
result = (struct val_neg_zone*)
rbtree_search(&neg->tree, lookfor.node.key);
return result;
}
/**
* Find the given data
* @param zone: negative zone
* @param nm: what to look for.
* @param len: length of nm
* @param labs: labels in nm
* @return data or NULL if not found.
*/
static struct val_neg_data* neg_find_data(struct val_neg_zone* zone,
uint8_t* nm, size_t len, int labs)
{
struct val_neg_data lookfor;
struct val_neg_data* result;
lookfor.node.key = &lookfor;
lookfor.name = nm;
lookfor.len = len;
lookfor.labs = labs;
result = (struct val_neg_data*)
rbtree_search(&zone->tree, lookfor.node.key);
return result;
}
/**
* Calculate space needed for the data and all its parents
* @param rep: NSEC entries.
* @return size.
*/
static size_t calc_data_need(struct reply_info* rep)
{
uint8_t* d;
size_t i, len, res = 0;
for(i=rep->an_numrrsets; i<rep->an_numrrsets+rep->ns_numrrsets; i++) {
if(ntohs(rep->rrsets[i]->rk.type) == LDNS_RR_TYPE_NSEC) {
d = rep->rrsets[i]->rk.dname;
len = rep->rrsets[i]->rk.dname_len;
res = sizeof(struct val_neg_data) + len;
while(!dname_is_root(d)) {
log_assert(len > 1); /* not root label */
dname_remove_label(&d, &len);
res += sizeof(struct val_neg_data) + len;
}
}
}
return res;
}
/**
* Calculate space needed for zone and all its parents
* @param d: name of zone
* @param len: length of name
* @return size.
*/
static size_t calc_zone_need(uint8_t* d, size_t len)
{
size_t res = sizeof(struct val_neg_zone) + len;
while(!dname_is_root(d)) {
log_assert(len > 1); /* not root label */
dname_remove_label(&d, &len);
res += sizeof(struct val_neg_zone) + len;
}
return res;
}
/**
* Find closest existing parent zone of the given name.
* @param neg: negative cache.
* @param nm: name to look for
* @param nm_len: length of nm
* @param labs: labelcount of nm.
* @param qclass: class.
* @return the zone or NULL if none found.
*/
static struct val_neg_zone* neg_closest_zone_parent(struct val_neg_cache* neg,
uint8_t* nm, size_t nm_len, int labs, uint16_t qclass)
{
struct val_neg_zone key;
struct val_neg_zone* result;
rbnode_t* res = NULL;
key.node.key = &key;
key.name = nm;
key.len = nm_len;
key.labs = labs;
key.dclass = qclass;
if(rbtree_find_less_equal(&neg->tree, &key, &res)) {
/* exact match */
result = (struct val_neg_zone*)res;
} else {
/* smaller element (or no element) */
int m;
result = (struct val_neg_zone*)res;
if(!result || result->dclass != qclass)
return NULL;
/* count number of labels matched */
(void)dname_lab_cmp(result->name, result->labs, key.name,
key.labs, &m);
while(result) { /* go up until qname is subdomain of stub */
if(result->labs <= m)
break;
result = result->parent;
}
}
return result;
}
/**
* Find closest existing parent data for the given name.
* @param zone: to look in.
* @param nm: name to look for
* @param nm_len: length of nm
* @param labs: labelcount of nm.
* @return the data or NULL if none found.
*/
static struct val_neg_data* neg_closest_data_parent(
struct val_neg_zone* zone, uint8_t* nm, size_t nm_len, int labs)
{
struct val_neg_data key;
struct val_neg_data* result;
rbnode_t* res = NULL;
key.node.key = &key;
key.name = nm;
key.len = nm_len;
key.labs = labs;
if(rbtree_find_less_equal(&zone->tree, &key, &res)) {
/* exact match */
result = (struct val_neg_data*)res;
} else {
/* smaller element (or no element) */
int m;
result = (struct val_neg_data*)res;
if(!result)
return NULL;
/* count number of labels matched */
(void)dname_lab_cmp(result->name, result->labs, key.name,
key.labs, &m);
while(result) { /* go up until qname is subdomain of stub */
if(result->labs <= m)
break;
result = result->parent;
}
}
return result;
}
/**
* Create a single zone node
* @param nm: name for zone (copied)
* @param nm_len: length of name
* @param labs: labels in name.
* @param dclass: class of zone, host order.
* @return new zone or NULL on failure
*/
static struct val_neg_zone* neg_setup_zone_node(
uint8_t* nm, size_t nm_len, int labs, uint16_t dclass)
{
struct val_neg_zone* zone =
(struct val_neg_zone*)calloc(1, sizeof(*zone));
if(!zone) {
return NULL;
}
zone->node.key = zone;
zone->name = memdup(nm, nm_len);
if(!zone->name) {
free(zone);
return NULL;
}
zone->len = nm_len;
zone->labs = labs;
zone->dclass = dclass;
rbtree_init(&zone->tree, &val_neg_data_compare);
return zone;
}
/**
* Create a linked list of parent zones, starting at longname ending on
* the parent (can be NULL, creates to the root).
* @param nm: name for lowest in chain
* @param nm_len: length of name
* @param labs: labels in name.
* @param dclass: class of zone.
* @param parent: NULL for to root, else so it fits under here.
* @return zone; a chain of zones and their parents up to the parent.
* or NULL on malloc failure
*/
static struct val_neg_zone* neg_zone_chain(
uint8_t* nm, size_t nm_len, int labs, uint16_t dclass,
struct val_neg_zone* parent)
{
int i;
int tolabs = parent?parent->labs:0;
struct val_neg_zone* zone, *prev = NULL, *first = NULL;
/* create the new subtree, i is labelcount of current creation */
/* this creates a 'first' to z->parent=NULL list of zones */
for(i=labs; i!=tolabs; i--) {
/* create new item */
zone = neg_setup_zone_node(nm, nm_len, i, dclass);
if(!zone) {
/* need to delete other allocations in this routine!*/
struct val_neg_zone* p=first, *np;
while(p) {
np = p->parent;
free(p);
free(p->name);
p = np;
}
return NULL;
}
if(i == labs) {
first = zone;
} else {
prev->parent = zone;
}
/* prepare for next name */
prev = zone;
dname_remove_label(&nm, &nm_len);
}
return first;
}
void val_neg_zone_take_inuse(struct val_neg_zone* zone)
{
if(!zone->in_use) {
struct val_neg_zone* p;
zone->in_use = 1;
/* increase usage count of all parents */
for(p=zone; p; p = p->parent) {
p->count++;
}
}
}
struct val_neg_zone* neg_create_zone(struct val_neg_cache* neg,
uint8_t* nm, size_t nm_len, uint16_t dclass)
{
struct val_neg_zone* zone;
struct val_neg_zone* parent;
struct val_neg_zone* p, *np;
int labs = dname_count_labels(nm);
/* find closest enclosing parent zone that (still) exists */
parent = neg_closest_zone_parent(neg, nm, nm_len, labs, dclass);
if(parent && query_dname_compare(parent->name, nm) == 0)
return parent; /* already exists, weird */
/* if parent exists, it is in use */
log_assert(!parent || parent->count > 0);
zone = neg_zone_chain(nm, nm_len, labs, dclass, parent);
if(!zone) {
return NULL;
}
/* insert the list of zones into the tree */
p = zone;
while(p) {
np = p->parent;
/* mem use */
neg->use += sizeof(struct val_neg_zone) + p->len;
/* insert in tree */
(void)rbtree_insert(&neg->tree, &p->node);
/* last one needs proper parent pointer */
if(np == NULL)
p->parent = parent;
p = np;
}
return zone;
}
/** find zone name of message, returns the SOA record */
static struct ub_packed_rrset_key* reply_find_soa(struct reply_info* rep)
{
size_t i;
for(i=rep->an_numrrsets; i< rep->an_numrrsets+rep->ns_numrrsets; i++){
if(ntohs(rep->rrsets[i]->rk.type) == LDNS_RR_TYPE_SOA)
return rep->rrsets[i];
}
return NULL;
}
/** see if the reply has NSEC records worthy of caching */
static int reply_has_nsec(struct reply_info* rep)
{
size_t i;
struct packed_rrset_data* d;
if(rep->security != sec_status_secure)
return 0;
for(i=rep->an_numrrsets; i< rep->an_numrrsets+rep->ns_numrrsets; i++){
if(ntohs(rep->rrsets[i]->rk.type) == LDNS_RR_TYPE_NSEC) {
d = (struct packed_rrset_data*)rep->rrsets[i]->
entry.data;
if(d->security == sec_status_secure)
return 1;
}
}
return 0;
}
/**
* Create single node of data element.
* @param nm: name (copied)
* @param nm_len: length of name
* @param labs: labels in name.
* @return element with name nm, or NULL malloc failure.
*/
static struct val_neg_data* neg_setup_data_node(
uint8_t* nm, size_t nm_len, int labs)
{
struct val_neg_data* el;
el = (struct val_neg_data*)calloc(1, sizeof(*el));
if(!el) {
return NULL;
}
el->node.key = el;
el->name = memdup(nm, nm_len);
if(!el->name) {
free(el);
return NULL;
}
el->len = nm_len;
el->labs = labs;
return el;
}
/**
* Create chain of data element and parents
* @param nm: name
* @param nm_len: length of name
* @param labs: labels in name.
* @param parent: up to where to make, if NULL up to root label.
* @return lowest element with name nm, or NULL malloc failure.
*/
static struct val_neg_data* neg_data_chain(
uint8_t* nm, size_t nm_len, int labs, struct val_neg_data* parent)
{
int i;
int tolabs = parent?parent->labs:0;
struct val_neg_data* el, *first = NULL, *prev = NULL;
/* create the new subtree, i is labelcount of current creation */
/* this creates a 'first' to z->parent=NULL list of zones */
for(i=labs; i!=tolabs; i--) {
/* create new item */
el = neg_setup_data_node(nm, nm_len, i);
if(!el) {
/* need to delete other allocations in this routine!*/
struct val_neg_data* p = first, *np;
while(p) {
np = p->parent;
free(p);
free(p->name);
p = np;
}
return NULL;
}
if(i == labs) {
first = el;
} else {
prev->parent = el;
}
/* prepare for next name */
prev = el;
dname_remove_label(&nm, &nm_len);
}
return first;
}
/**
* Remove NSEC records between start and end points.
* By walking the tree, the tree is sorted canonically.
* @param neg: negative cache.
* @param zone: the zone
* @param el: element to start walking at.
* @param nsec: the nsec record with the end point
*/
static void wipeout(struct val_neg_cache* neg, struct val_neg_zone* zone,
struct val_neg_data* el, struct ub_packed_rrset_key* nsec)
{
struct packed_rrset_data* d = (struct packed_rrset_data*)nsec->
entry.data;
uint8_t* end;
size_t end_len;
int end_labs, m;
rbnode_t* walk, *next;
struct val_neg_data* cur;
uint8_t buf[257];
/* get endpoint */
if(!d || d->count == 0 || d->rr_len[0] < 2+1)
return;
if(ntohs(nsec->rk.type) == LDNS_RR_TYPE_NSEC) {
end = d->rr_data[0]+2;
end_len = dname_valid(end, d->rr_len[0]-2);
end_labs = dname_count_labels(end);
} else {
/* NSEC3 */
if(!nsec3_get_nextowner_b32(nsec, 0, buf, sizeof(buf)))
return;
end = buf;
end_labs = dname_count_size_labels(end, &end_len);
}
/* sanity check, both owner and end must be below the zone apex */
if(!dname_subdomain_c(el->name, zone->name) ||
!dname_subdomain_c(end, zone->name))
return;
/* detect end of zone NSEC ; wipe until the end of zone */
if(query_dname_compare(end, zone->name) == 0) {
end = NULL;
}
walk = rbtree_next(&el->node);
while(walk && walk != RBTREE_NULL) {
cur = (struct val_neg_data*)walk;
/* sanity check: must be larger than start */
if(dname_canon_lab_cmp(cur->name, cur->labs,
el->name, el->labs, &m) <= 0) {
/* r == 0 skip original record. */
/* r < 0 too small! */
walk = rbtree_next(walk);
continue;
}
/* stop at endpoint, also data at empty nonterminals must be
* removed (no NSECs there) so everything between
* start and end */
if(end && dname_canon_lab_cmp(cur->name, cur->labs,
end, end_labs, &m) >= 0) {
break;
}
/* this element has to be deleted, but we cannot do it
* now, because we are walking the tree still ... */
/* get the next element: */
next = rbtree_next(walk);
/* now delete the original element, this may trigger
* rbtree rebalances, but really, the next element is
* the one we need.
* But it may trigger delete of other data and the
* entire zone. However, if that happens, this is done
* by deleting the *parents* of the element for deletion,
* and maybe also the entire zone if it is empty.
* But parents are smaller in canonical compare, thus,
* if a larger element exists, then it is not a parent,
* it cannot get deleted, the zone cannot get empty.
* If the next==NULL, then zone can be empty. */
if(cur->in_use)
neg_delete_data(neg, cur);
walk = next;
}
}
void neg_insert_data(struct val_neg_cache* neg,
struct val_neg_zone* zone, struct ub_packed_rrset_key* nsec)
{
struct packed_rrset_data* d;
struct val_neg_data* parent;
struct val_neg_data* el;
uint8_t* nm = nsec->rk.dname;
size_t nm_len = nsec->rk.dname_len;
int labs = dname_count_labels(nsec->rk.dname);
d = (struct packed_rrset_data*)nsec->entry.data;
if( !(d->security == sec_status_secure ||
(d->security == sec_status_unchecked && d->rrsig_count > 0)))
return;
log_nametypeclass(VERB_ALGO, "negcache rr",
nsec->rk.dname, ntohs(nsec->rk.type),
ntohs(nsec->rk.rrset_class));
/* find closest enclosing parent data that (still) exists */
parent = neg_closest_data_parent(zone, nm, nm_len, labs);
if(parent && query_dname_compare(parent->name, nm) == 0) {
/* perfect match already exists */
log_assert(parent->count > 0);
el = parent;
} else {
struct val_neg_data* p, *np;
/* create subtree for perfect match */
/* if parent exists, it is in use */
log_assert(!parent || parent->count > 0);
el = neg_data_chain(nm, nm_len, labs, parent);
if(!el) {
log_err("out of memory inserting NSEC negative cache");
return;
}
el->in_use = 0; /* set on below */
/* insert the list of zones into the tree */
p = el;
while(p) {
np = p->parent;
/* mem use */
neg->use += sizeof(struct val_neg_data) + p->len;
/* insert in tree */
p->zone = zone;
(void)rbtree_insert(&zone->tree, &p->node);
/* last one needs proper parent pointer */
if(np == NULL)
p->parent = parent;
p = np;
}
}
if(!el->in_use) {
struct val_neg_data* p;
el->in_use = 1;
/* increase usage count of all parents */
for(p=el; p; p = p->parent) {
p->count++;
}
neg_lru_front(neg, el);
} else {
/* in use, bring to front, lru */
neg_lru_touch(neg, el);
}
/* if nsec3 store last used parameters */
if(ntohs(nsec->rk.type) == LDNS_RR_TYPE_NSEC3) {
int h;
uint8_t* s;
size_t slen, it;
if(nsec3_get_params(nsec, 0, &h, &it, &s, &slen) &&
it <= neg->nsec3_max_iter &&
(h != zone->nsec3_hash || it != zone->nsec3_iter ||
slen != zone->nsec3_saltlen ||
memcmp(zone->nsec3_salt, s, slen) != 0)) {
uint8_t* sa = memdup(s, slen);
if(sa) {
free(zone->nsec3_salt);
zone->nsec3_salt = sa;
zone->nsec3_saltlen = slen;
zone->nsec3_hash = h;
zone->nsec3_iter = it;
}
}
}
/* wipe out the cache items between NSEC start and end */
wipeout(neg, zone, el, nsec);
}
void val_neg_addreply(struct val_neg_cache* neg, struct reply_info* rep)
{
size_t i, need;
struct ub_packed_rrset_key* soa;
struct val_neg_zone* zone;
/* see if secure nsecs inside */
if(!reply_has_nsec(rep))
return;
/* find the zone name in message */
soa = reply_find_soa(rep);
if(!soa)
return;
log_nametypeclass(VERB_ALGO, "negcache insert for zone",
soa->rk.dname, LDNS_RR_TYPE_SOA, ntohs(soa->rk.rrset_class));
/* ask for enough space to store all of it */
need = calc_data_need(rep) +
calc_zone_need(soa->rk.dname, soa->rk.dname_len);
lock_basic_lock(&neg->lock);
neg_make_space(neg, need);
/* find or create the zone entry */
zone = neg_find_zone(neg, soa->rk.dname, soa->rk.dname_len,
ntohs(soa->rk.rrset_class));
if(!zone) {
if(!(zone = neg_create_zone(neg, soa->rk.dname,
soa->rk.dname_len, ntohs(soa->rk.rrset_class)))) {
lock_basic_unlock(&neg->lock);
log_err("out of memory adding negative zone");
return;
}
}
val_neg_zone_take_inuse(zone);
/* insert the NSECs */
for(i=rep->an_numrrsets; i< rep->an_numrrsets+rep->ns_numrrsets; i++){
if(ntohs(rep->rrsets[i]->rk.type) != LDNS_RR_TYPE_NSEC)
continue;
if(!dname_subdomain_c(rep->rrsets[i]->rk.dname,
zone->name)) continue;
/* insert NSEC into this zone's tree */
neg_insert_data(neg, zone, rep->rrsets[i]);
}
if(zone->tree.count == 0) {
/* remove empty zone if inserts failed */
neg_delete_zone(neg, zone);
}
lock_basic_unlock(&neg->lock);
}
/**
* Lookup closest data record. For NSEC denial.
* @param zone: zone to look in
* @param qname: name to look for.
* @param len: length of name
* @param labs: labels in name
* @param data: data element, exact or smaller or NULL
* @return true if exact match.
*/
static int neg_closest_data(struct val_neg_zone* zone,
uint8_t* qname, size_t len, int labs, struct val_neg_data** data)
{
struct val_neg_data key;
rbnode_t* r;
key.node.key = &key;
key.name = qname;
key.len = len;
key.labs = labs;
if(rbtree_find_less_equal(&zone->tree, &key, &r)) {
/* exact match */
*data = (struct val_neg_data*)r;
return 1;
} else {
/* smaller match */
*data = (struct val_neg_data*)r;
return 0;
}
}
int val_neg_dlvlookup(struct val_neg_cache* neg, uint8_t* qname, size_t len,
uint16_t qclass, struct rrset_cache* rrset_cache, uint32_t now)
{
/* lookup closest zone */
struct val_neg_zone* zone;
struct val_neg_data* data;
int labs;
struct ub_packed_rrset_key* nsec;
struct packed_rrset_data* d;
uint32_t flags;
uint8_t* wc;
struct query_info qinfo;
if(!neg) return 0;
log_nametypeclass(VERB_ALGO, "negcache dlvlookup", qname,
LDNS_RR_TYPE_DLV, qclass);
labs = dname_count_labels(qname);
lock_basic_lock(&neg->lock);
zone = neg_closest_zone_parent(neg, qname, len, labs, qclass);
while(zone && !zone->in_use)
zone = zone->parent;
if(!zone) {
lock_basic_unlock(&neg->lock);
return 0;
}
log_nametypeclass(VERB_ALGO, "negcache zone", zone->name, 0,
zone->dclass);
/* DLV is defined to use NSEC only */
if(zone->nsec3_hash) {
lock_basic_unlock(&neg->lock);
return 0;
}
/* lookup closest data record */
(void)neg_closest_data(zone, qname, len, labs, &data);
while(data && !data->in_use)
data = data->parent;
if(!data) {
lock_basic_unlock(&neg->lock);
return 0;
}
log_nametypeclass(VERB_ALGO, "negcache rr", data->name,
LDNS_RR_TYPE_NSEC, zone->dclass);
/* lookup rrset in rrset cache */
flags = 0;
if(query_dname_compare(data->name, zone->name) == 0)
flags = PACKED_RRSET_NSEC_AT_APEX;
nsec = rrset_cache_lookup(rrset_cache, data->name, data->len,
LDNS_RR_TYPE_NSEC, zone->dclass, flags, now, 0);
/* check if secure and TTL ok */
if(!nsec) {
lock_basic_unlock(&neg->lock);
return 0;
}
d = (struct packed_rrset_data*)nsec->entry.data;
if(!d || now > d->ttl) {
lock_rw_unlock(&nsec->entry.lock);
/* delete data record if expired */
neg_delete_data(neg, data);
lock_basic_unlock(&neg->lock);
return 0;
}
if(d->security != sec_status_secure) {
lock_rw_unlock(&nsec->entry.lock);
neg_delete_data(neg, data);
lock_basic_unlock(&neg->lock);
return 0;
}
verbose(VERB_ALGO, "negcache got secure rrset");
/* check NSEC security */
/* check if NSEC proves no DLV type exists */
/* check if NSEC proves NXDOMAIN for qname */
qinfo.qname = qname;
qinfo.qtype = LDNS_RR_TYPE_DLV;
qinfo.qclass = qclass;
if(!nsec_proves_nodata(nsec, &qinfo, &wc) &&
!val_nsec_proves_name_error(nsec, qname)) {
/* the NSEC is not a denial for the DLV */
lock_rw_unlock(&nsec->entry.lock);
lock_basic_unlock(&neg->lock);
verbose(VERB_ALGO, "negcache not proven");
return 0;
}
/* so the NSEC was a NODATA proof, or NXDOMAIN proof. */
/* no need to check for wildcard NSEC; no wildcards in DLV repos */
/* no need to lookup SOA record for client; no response message */
lock_rw_unlock(&nsec->entry.lock);
/* if OK touch the LRU for neg_data element */
neg_lru_touch(neg, data);
lock_basic_unlock(&neg->lock);
verbose(VERB_ALGO, "negcache DLV denial proven");
return 1;
}
/** see if the reply has signed NSEC records and return the signer */
static uint8_t* reply_nsec_signer(struct reply_info* rep, size_t* signer_len,
uint16_t* dclass)
{
size_t i;
struct packed_rrset_data* d;
uint8_t* s;
for(i=rep->an_numrrsets; i< rep->an_numrrsets+rep->ns_numrrsets; i++){
if(ntohs(rep->rrsets[i]->rk.type) == LDNS_RR_TYPE_NSEC ||
ntohs(rep->rrsets[i]->rk.type) == LDNS_RR_TYPE_NSEC3) {
d = (struct packed_rrset_data*)rep->rrsets[i]->
entry.data;
/* return first signer name of first NSEC */
if(d->rrsig_count != 0) {
val_find_rrset_signer(rep->rrsets[i],
&s, signer_len);
if(s && *signer_len) {
*dclass = ntohs(rep->rrsets[i]->
rk.rrset_class);
return s;
}
}
}
}
return 0;
}
void val_neg_addreferral(struct val_neg_cache* neg, struct reply_info* rep,
uint8_t* zone_name)
{
size_t i, need;
uint8_t* signer;
size_t signer_len;
uint16_t dclass;
struct val_neg_zone* zone;
/* no SOA in this message, find RRSIG over NSEC's signer name.
* note the NSEC records are maybe not validated yet */
signer = reply_nsec_signer(rep, &signer_len, &dclass);
if(!signer)
return;
if(!dname_subdomain_c(signer, zone_name)) {
/* the signer is not in the bailiwick, throw it out */
return;
}
log_nametypeclass(VERB_ALGO, "negcache insert referral ",
signer, LDNS_RR_TYPE_NS, dclass);
/* ask for enough space to store all of it */
need = calc_data_need(rep) + calc_zone_need(signer, signer_len);
lock_basic_lock(&neg->lock);
neg_make_space(neg, need);
/* find or create the zone entry */
zone = neg_find_zone(neg, signer, signer_len, dclass);
if(!zone) {
if(!(zone = neg_create_zone(neg, signer, signer_len,
dclass))) {
lock_basic_unlock(&neg->lock);
log_err("out of memory adding negative zone");
return;
}
}
val_neg_zone_take_inuse(zone);
/* insert the NSECs */
for(i=rep->an_numrrsets; i< rep->an_numrrsets+rep->ns_numrrsets; i++){
if(ntohs(rep->rrsets[i]->rk.type) != LDNS_RR_TYPE_NSEC &&
ntohs(rep->rrsets[i]->rk.type) != LDNS_RR_TYPE_NSEC3)
continue;
if(!dname_subdomain_c(rep->rrsets[i]->rk.dname,
zone->name)) continue;
/* insert NSEC into this zone's tree */
neg_insert_data(neg, zone, rep->rrsets[i]);
}
if(zone->tree.count == 0) {
/* remove empty zone if inserts failed */
neg_delete_zone(neg, zone);
}
lock_basic_unlock(&neg->lock);
}
/**
* Check that an NSEC3 rrset does not have a type set.
* None of the nsec3s in a hash-collision are allowed to have the type.
* (since we do not know which one is the nsec3 looked at, flags, ..., we
* ignore the cached item and let it bypass negative caching).
* @param k: the nsec3 rrset to check.
* @param t: type to check
* @return true if no RRs have the type.
*/
static int nsec3_no_type(struct ub_packed_rrset_key* k, uint16_t t)
{
int count = (int)((struct packed_rrset_data*)k->entry.data)->count;
int i;
for(i=0; i<count; i++)
if(nsec3_has_type(k, i, t))
return 0;
return 1;
}
/**
* See if rrset exists in rrset cache.
* If it does, the bit is checked, and if not expired, it is returned
* allocated in region.
* @param rrset_cache: rrset cache
* @param qname: to lookup rrset name
* @param qname_len: length of qname.
* @param qtype: type of rrset to lookup, host order
* @param qclass: class of rrset to lookup, host order
* @param flags: flags for rrset to lookup
* @param region: where to alloc result
* @param checkbit: if true, a bit in the nsec typemap is checked for absence.
* @param checktype: which bit to check
* @param now: to check ttl against
* @return rrset or NULL
*/
static struct ub_packed_rrset_key*
grab_nsec(struct rrset_cache* rrset_cache, uint8_t* qname, size_t qname_len,
uint16_t qtype, uint16_t qclass, uint32_t flags,
struct regional* region, int checkbit, uint16_t checktype,
uint32_t now)
{
struct ub_packed_rrset_key* r, *k = rrset_cache_lookup(rrset_cache,
qname, qname_len, qtype, qclass, flags, now, 0);
struct packed_rrset_data* d;
if(!k) return NULL;
d = (struct packed_rrset_data*)k->entry.data;
if(d->ttl < now) {
lock_rw_unlock(&k->entry.lock);
return NULL;
}
/* only secure or unchecked records that have signatures. */
if( ! ( d->security == sec_status_secure ||
(d->security == sec_status_unchecked &&
d->rrsig_count > 0) ) ) {
lock_rw_unlock(&k->entry.lock);
return NULL;
}
/* check if checktype is absent */
if(checkbit && (
(qtype == LDNS_RR_TYPE_NSEC && nsec_has_type(k, checktype)) ||
(qtype == LDNS_RR_TYPE_NSEC3 && !nsec3_no_type(k, checktype))
)) {
lock_rw_unlock(&k->entry.lock);
return NULL;
}
/* looks OK! copy to region and return it */
r = packed_rrset_copy_region(k, region, now);
/* if it failed, we return the NULL */
lock_rw_unlock(&k->entry.lock);
return r;
}
/** find nsec3 closest encloser in neg cache */
static struct val_neg_data*
neg_find_nsec3_ce(struct val_neg_zone* zone, uint8_t* qname, size_t qname_len,
int qlabs, ldns_buffer* buf, uint8_t* hashnc, size_t* nclen)
{
struct val_neg_data* data;
uint8_t hashce[SHA_DIGEST_LENGTH];
uint8_t b32[257];
size_t celen, b32len;
*nclen = 0;
while(qlabs > 0) {
/* hash */
if(!(celen=nsec3_get_hashed(buf, qname, qname_len,
zone->nsec3_hash, zone->nsec3_iter, zone->nsec3_salt,
zone->nsec3_saltlen, hashce, sizeof(hashce))))
return NULL;
if(!(b32len=nsec3_hash_to_b32(hashce, celen, zone->name,
zone->len, b32, sizeof(b32))))
return NULL;
/* lookup (exact match only) */
data = neg_find_data(zone, b32, b32len, zone->labs+1);
if(data && data->in_use) {
/* found ce match! */
return data;
}
*nclen = celen;
memmove(hashnc, hashce, celen);
dname_remove_label(&qname, &qname_len);
qlabs --;
}
return NULL;
}
/** check nsec3 parameters on nsec3 rrset with current zone values */
static int
neg_params_ok(struct val_neg_zone* zone, struct ub_packed_rrset_key* rrset)
{
int h;
uint8_t* s;
size_t slen, it;
if(!nsec3_get_params(rrset, 0, &h, &it, &s, &slen))
return 0;
return (h == zone->nsec3_hash && it == zone->nsec3_iter &&
slen == zone->nsec3_saltlen &&
memcmp(zone->nsec3_salt, s, slen) == 0);
}
/** get next closer for nsec3 proof */
static struct ub_packed_rrset_key*
neg_nsec3_getnc(struct val_neg_zone* zone, uint8_t* hashnc, size_t nclen,
struct rrset_cache* rrset_cache, struct regional* region,
uint32_t now, uint8_t* b32, size_t maxb32)
{
struct ub_packed_rrset_key* nc_rrset;
struct val_neg_data* data;
size_t b32len;
if(!(b32len=nsec3_hash_to_b32(hashnc, nclen, zone->name,
zone->len, b32, maxb32)))
return NULL;
(void)neg_closest_data(zone, b32, b32len, zone->labs+1, &data);
if(!data && zone->tree.count != 0) {
/* could be before the first entry ; return the last
* entry (possibly the rollover nsec3 at end) */
data = (struct val_neg_data*)rbtree_last(&zone->tree);
}
while(data && !data->in_use)
data = data->parent;
if(!data)
return NULL;
/* got a data element in tree, grab it */
nc_rrset = grab_nsec(rrset_cache, data->name, data->len,
LDNS_RR_TYPE_NSEC3, zone->dclass, 0, region, 0, 0, now);
if(!nc_rrset)
return NULL;
if(!neg_params_ok(zone, nc_rrset))
return NULL;
return nc_rrset;
}
/** neg cache nsec3 proof procedure*/
static struct dns_msg*
neg_nsec3_proof_ds(struct val_neg_zone* zone, uint8_t* qname, size_t qname_len,
int qlabs, ldns_buffer* buf, struct rrset_cache* rrset_cache,
struct regional* region, uint32_t now, uint8_t* topname)
{
struct dns_msg* msg;
struct val_neg_data* data;
uint8_t hashnc[SHA_DIGEST_LENGTH];
size_t nclen;
struct ub_packed_rrset_key* ce_rrset, *nc_rrset;
struct nsec3_cached_hash c;
uint8_t nc_b32[257];
/* for NSEC3 ; determine the closest encloser for which we
* can find an exact match. Remember the hashed lower name,
* since that is the one we need a closest match for.
* If we find a match straight away, then it becomes NODATA.
* Otherwise, NXDOMAIN or if OPTOUT, an insecure delegation.
* Also check that parameters are the same on closest encloser
* and on closest match.
*/
if(!zone->nsec3_hash)
return NULL; /* not nsec3 zone */
if(!(data=neg_find_nsec3_ce(zone, qname, qname_len, qlabs, buf,
hashnc, &nclen))) {
return NULL;
}
/* grab the ce rrset */
ce_rrset = grab_nsec(rrset_cache, data->name, data->len,
LDNS_RR_TYPE_NSEC3, zone->dclass, 0, region, 1,
LDNS_RR_TYPE_DS, now);
if(!ce_rrset)
return NULL;
if(!neg_params_ok(zone, ce_rrset))
return NULL;
if(nclen == 0) {
/* exact match, just check the type bits */
/* need: -SOA, -DS, +NS */
if(nsec3_has_type(ce_rrset, 0, LDNS_RR_TYPE_SOA) ||
nsec3_has_type(ce_rrset, 0, LDNS_RR_TYPE_DS) ||
!nsec3_has_type(ce_rrset, 0, LDNS_RR_TYPE_NS))
return NULL;
if(!(msg = dns_msg_create(qname, qname_len,
LDNS_RR_TYPE_DS, zone->dclass, region, 1)))
return NULL;
/* TTL reduced in grab_nsec */
if(!dns_msg_authadd(msg, region, ce_rrset, 0))
return NULL;
return msg;
}
/* optout is not allowed without knowing the trust-anchor in use,
* otherwise the optout could spoof away that anchor */
if(!topname)
return NULL;
/* if there is no exact match, it must be in an optout span
* (an existing DS implies an NSEC3 must exist) */
nc_rrset = neg_nsec3_getnc(zone, hashnc, nclen, rrset_cache,
region, now, nc_b32, sizeof(nc_b32));
if(!nc_rrset)
return NULL;
if(!neg_params_ok(zone, nc_rrset))
return NULL;
if(!nsec3_has_optout(nc_rrset, 0))
return NULL;
c.hash = hashnc;
c.hash_len = nclen;
c.b32 = nc_b32+1;
c.b32_len = (size_t)nc_b32[0];
if(nsec3_covers(zone->name, &c, nc_rrset, 0, buf)) {
/* nc_rrset covers the next closer name.
* ce_rrset equals a closer encloser.
* nc_rrset is optout.
* No need to check wildcard for type DS */
/* capacity=3: ce + nc + soa(if needed) */
if(!(msg = dns_msg_create(qname, qname_len,
LDNS_RR_TYPE_DS, zone->dclass, region, 3)))
return NULL;
/* now=0 because TTL was reduced in grab_nsec */
if(!dns_msg_authadd(msg, region, ce_rrset, 0))
return NULL;
if(!dns_msg_authadd(msg, region, nc_rrset, 0))
return NULL;
return msg;
}
return NULL;
}
/**
* Add SOA record for external responses.
* @param rrset_cache: to look into.
* @param now: current time.
* @param region: where to perform the allocation
* @param msg: current msg with NSEC.
* @param zone: val_neg_zone if we have one.
* @return false on lookup or alloc failure.
*/
static int add_soa(struct rrset_cache* rrset_cache, uint32_t now,
struct regional* region, struct dns_msg* msg, struct val_neg_zone* zone)
{
struct ub_packed_rrset_key* soa;
uint8_t* nm;
size_t nmlen;
uint16_t dclass;
if(zone) {
nm = zone->name;
nmlen = zone->len;
dclass = zone->dclass;
} else {
/* Assumes the signer is the zone SOA to add */
nm = reply_nsec_signer(msg->rep, &nmlen, &dclass);
if(!nm)
return 0;
}
soa = rrset_cache_lookup(rrset_cache, nm, nmlen, LDNS_RR_TYPE_SOA,
dclass, PACKED_RRSET_SOA_NEG, now, 0);
if(!soa)
return 0;
if(!dns_msg_authadd(msg, region, soa, now)) {
lock_rw_unlock(&soa->entry.lock);
return 0;
}
lock_rw_unlock(&soa->entry.lock);
return 1;
}
struct dns_msg*
val_neg_getmsg(struct val_neg_cache* neg, struct query_info* qinfo,
struct regional* region, struct rrset_cache* rrset_cache,
ldns_buffer* buf, uint32_t now, int addsoa, uint8_t* topname)
{
struct dns_msg* msg;
struct ub_packed_rrset_key* rrset;
uint8_t* zname;
size_t zname_len;
int zname_labs;
struct val_neg_zone* zone;
/* only for DS queries */
if(qinfo->qtype != LDNS_RR_TYPE_DS)
return NULL;
log_assert(!topname || dname_subdomain_c(qinfo->qname, topname));
/* see if info from neg cache is available
* For NSECs, because there is no optout; a DS next to a delegation
* always has exactly an NSEC for it itself; check its DS bit.
* flags=0 (not the zone apex).
*/
rrset = grab_nsec(rrset_cache, qinfo->qname, qinfo->qname_len,
LDNS_RR_TYPE_NSEC, qinfo->qclass, 0, region, 1,
qinfo->qtype, now);
if(rrset) {
/* return msg with that rrset */
if(!(msg = dns_msg_create(qinfo->qname, qinfo->qname_len,
qinfo->qtype, qinfo->qclass, region, 2)))
return NULL;
/* TTL already subtracted in grab_nsec */
if(!dns_msg_authadd(msg, region, rrset, 0))
return NULL;
if(addsoa && !add_soa(rrset_cache, now, region, msg, NULL))
return NULL;
return msg;
}
/* check NSEC3 neg cache for type DS */
/* need to look one zone higher for DS type */
zname = qinfo->qname;
zname_len = qinfo->qname_len;
dname_remove_label(&zname, &zname_len);
zname_labs = dname_count_labels(zname);
/* lookup closest zone */
lock_basic_lock(&neg->lock);
zone = neg_closest_zone_parent(neg, zname, zname_len, zname_labs,
qinfo->qclass);
while(zone && !zone->in_use)
zone = zone->parent;
/* check that the zone is not too high up so that we do not pick data
* out of a zone that is above the last-seen key (or trust-anchor). */
if(zone && topname) {
if(!dname_subdomain_c(zone->name, topname))
zone = NULL;
}
if(!zone) {
lock_basic_unlock(&neg->lock);
return NULL;
}
msg = neg_nsec3_proof_ds(zone, qinfo->qname, qinfo->qname_len,
zname_labs+1, buf, rrset_cache, region, now, topname);
if(msg && addsoa && !add_soa(rrset_cache, now, region, msg, zone)) {
lock_basic_unlock(&neg->lock);
return NULL;
}
lock_basic_unlock(&neg->lock);
return msg;
}