monero/external/unbound/validator/val_neg.c
Erik de Castro Lopo a85b5759f3 Upgrade unbound library
These files were pulled from the 1.6.3 release tarball.

This new version builds against OpenSSL version 1.1 which will be
the default in the new Debian Stable which is due to be released
RealSoonNow (tm).
2017-06-17 23:04:00 +10:00

1471 lines
40 KiB
C

/*
* 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 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.
* The functions help with aggressive negative caching.
* This creates new denials of existence, and proofs for absence of types
* from cached NSEC records.
*/
#include "config.h"
#ifdef HAVE_OPENSSL_SSL_H
#include "openssl/ssl.h"
#define NSEC3_SHA_LEN SHA_DIGEST_LENGTH
#else
#define NSEC3_SHA_LEN 20
#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"
#include "sldns/rrdef.h"
#include "sldns/sbuffer.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_type* 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_type* 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_type* 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_type* 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->name);
free(p);
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->name);
free(p);
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_type* 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)) {
if(slen > 0) {
uint8_t* sa = memdup(s, slen);
if(sa) {
free(zone->nsec3_salt);
zone->nsec3_salt = sa;
zone->nsec3_saltlen = slen;
zone->nsec3_iter = it;
zone->nsec3_hash = h;
}
} else {
free(zone->nsec3_salt);
zone->nsec3_salt = NULL;
zone->nsec3_saltlen = 0;
zone->nsec3_iter = it;
zone->nsec3_hash = h;
}
}
}
/* 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_type* 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, time_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;
qinfo.local_alias = NULL;
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,
time_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, sldns_buffer* buf, uint8_t* hashnc, size_t* nclen)
{
struct val_neg_data* data;
uint8_t hashce[NSEC3_SHA_LEN];
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,
time_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, sldns_buffer* buf, struct rrset_cache* rrset_cache,
struct regional* region, time_t now, uint8_t* topname)
{
struct dns_msg* msg;
struct val_neg_data* data;
uint8_t hashnc[NSEC3_SHA_LEN];
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, time_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,
sldns_buffer* buf, time_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;
}