monero/external/unbound/validator/val_nsec3.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

1434 lines
45 KiB
C

/*
* validator/val_nsec3.c - validator NSEC3 denial of existence 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.
* The functions help with NSEC3 checking, the different NSEC3 proofs
* for denial of existence, and proofs for presence of types.
*/
#include "config.h"
#include <ctype.h>
#include "validator/val_nsec3.h"
#include "validator/val_secalgo.h"
#include "validator/validator.h"
#include "validator/val_kentry.h"
#include "services/cache/rrset.h"
#include "util/regional.h"
#include "util/rbtree.h"
#include "util/module.h"
#include "util/net_help.h"
#include "util/data/packed_rrset.h"
#include "util/data/dname.h"
#include "util/data/msgreply.h"
/* we include nsec.h for the bitmap_has_type function */
#include "validator/val_nsec.h"
#include "sldns/sbuffer.h"
/**
* This function we get from ldns-compat or from base system
* it returns the number of data bytes stored at the target, or <0 on error.
*/
int sldns_b32_ntop_extended_hex(uint8_t const *src, size_t srclength,
char *target, size_t targsize);
/**
* This function we get from ldns-compat or from base system
* it returns the number of data bytes stored at the target, or <0 on error.
*/
int sldns_b32_pton_extended_hex(char const *src, size_t hashed_owner_str_len,
uint8_t *target, size_t targsize);
/**
* Closest encloser (ce) proof results
* Contains the ce and the next-closer (nc) proof.
*/
struct ce_response {
/** the closest encloser name */
uint8_t* ce;
/** length of ce */
size_t ce_len;
/** NSEC3 record that proved ce. rrset */
struct ub_packed_rrset_key* ce_rrset;
/** NSEC3 record that proved ce. rr number */
int ce_rr;
/** NSEC3 record that proved nc. rrset */
struct ub_packed_rrset_key* nc_rrset;
/** NSEC3 record that proved nc. rr*/
int nc_rr;
};
/**
* Filter conditions for NSEC3 proof
* Used to iterate over the applicable NSEC3 RRs.
*/
struct nsec3_filter {
/** Zone name, only NSEC3 records for this zone are considered */
uint8_t* zone;
/** length of the zonename */
size_t zone_len;
/** the list of NSEC3s to filter; array */
struct ub_packed_rrset_key** list;
/** number of rrsets in list */
size_t num;
/** class of records for the NSEC3, only this class applies */
uint16_t fclass;
};
/** return number of rrs in an rrset */
static size_t
rrset_get_count(struct ub_packed_rrset_key* rrset)
{
struct packed_rrset_data* d = (struct packed_rrset_data*)
rrset->entry.data;
if(!d) return 0;
return d->count;
}
/** return if nsec3 RR has unknown flags */
static int
nsec3_unknown_flags(struct ub_packed_rrset_key* rrset, int r)
{
struct packed_rrset_data* d = (struct packed_rrset_data*)
rrset->entry.data;
log_assert(d && r < (int)d->count);
if(d->rr_len[r] < 2+2)
return 0; /* malformed */
return (int)(d->rr_data[r][2+1] & NSEC3_UNKNOWN_FLAGS);
}
int
nsec3_has_optout(struct ub_packed_rrset_key* rrset, int r)
{
struct packed_rrset_data* d = (struct packed_rrset_data*)
rrset->entry.data;
log_assert(d && r < (int)d->count);
if(d->rr_len[r] < 2+2)
return 0; /* malformed */
return (int)(d->rr_data[r][2+1] & NSEC3_OPTOUT);
}
/** return nsec3 RR algorithm */
static int
nsec3_get_algo(struct ub_packed_rrset_key* rrset, int r)
{
struct packed_rrset_data* d = (struct packed_rrset_data*)
rrset->entry.data;
log_assert(d && r < (int)d->count);
if(d->rr_len[r] < 2+1)
return 0; /* malformed */
return (int)(d->rr_data[r][2+0]);
}
/** return if nsec3 RR has known algorithm */
static int
nsec3_known_algo(struct ub_packed_rrset_key* rrset, int r)
{
struct packed_rrset_data* d = (struct packed_rrset_data*)
rrset->entry.data;
log_assert(d && r < (int)d->count);
if(d->rr_len[r] < 2+1)
return 0; /* malformed */
switch(d->rr_data[r][2+0]) {
case NSEC3_HASH_SHA1:
return 1;
}
return 0;
}
/** return nsec3 RR iteration count */
static size_t
nsec3_get_iter(struct ub_packed_rrset_key* rrset, int r)
{
uint16_t i;
struct packed_rrset_data* d = (struct packed_rrset_data*)
rrset->entry.data;
log_assert(d && r < (int)d->count);
if(d->rr_len[r] < 2+4)
return 0; /* malformed */
memmove(&i, d->rr_data[r]+2+2, sizeof(i));
i = ntohs(i);
return (size_t)i;
}
/** return nsec3 RR salt */
static int
nsec3_get_salt(struct ub_packed_rrset_key* rrset, int r,
uint8_t** salt, size_t* saltlen)
{
struct packed_rrset_data* d = (struct packed_rrset_data*)
rrset->entry.data;
log_assert(d && r < (int)d->count);
if(d->rr_len[r] < 2+5) {
*salt = 0;
*saltlen = 0;
return 0; /* malformed */
}
*saltlen = (size_t)d->rr_data[r][2+4];
if(d->rr_len[r] < 2+5+(size_t)*saltlen) {
*salt = 0;
*saltlen = 0;
return 0; /* malformed */
}
*salt = d->rr_data[r]+2+5;
return 1;
}
int nsec3_get_params(struct ub_packed_rrset_key* rrset, int r,
int* algo, size_t* iter, uint8_t** salt, size_t* saltlen)
{
if(!nsec3_known_algo(rrset, r) || nsec3_unknown_flags(rrset, r))
return 0;
if(!nsec3_get_salt(rrset, r, salt, saltlen))
return 0;
*algo = nsec3_get_algo(rrset, r);
*iter = nsec3_get_iter(rrset, r);
return 1;
}
int
nsec3_get_nextowner(struct ub_packed_rrset_key* rrset, int r,
uint8_t** next, size_t* nextlen)
{
size_t saltlen;
struct packed_rrset_data* d = (struct packed_rrset_data*)
rrset->entry.data;
log_assert(d && r < (int)d->count);
if(d->rr_len[r] < 2+5) {
*next = 0;
*nextlen = 0;
return 0; /* malformed */
}
saltlen = (size_t)d->rr_data[r][2+4];
if(d->rr_len[r] < 2+5+saltlen+1) {
*next = 0;
*nextlen = 0;
return 0; /* malformed */
}
*nextlen = (size_t)d->rr_data[r][2+5+saltlen];
if(d->rr_len[r] < 2+5+saltlen+1+*nextlen) {
*next = 0;
*nextlen = 0;
return 0; /* malformed */
}
*next = d->rr_data[r]+2+5+saltlen+1;
return 1;
}
size_t nsec3_hash_to_b32(uint8_t* hash, size_t hashlen, uint8_t* zone,
size_t zonelen, uint8_t* buf, size_t max)
{
/* write b32 of name, leave one for length */
int ret;
if(max < hashlen*2+1) /* quick approx of b32, as if hexb16 */
return 0;
ret = sldns_b32_ntop_extended_hex(hash, hashlen, (char*)buf+1, max-1);
if(ret < 1)
return 0;
buf[0] = (uint8_t)ret; /* length of b32 label */
ret++;
if(max - ret < zonelen)
return 0;
memmove(buf+ret, zone, zonelen);
return zonelen+(size_t)ret;
}
size_t nsec3_get_nextowner_b32(struct ub_packed_rrset_key* rrset, int r,
uint8_t* buf, size_t max)
{
uint8_t* nm, *zone;
size_t nmlen, zonelen;
if(!nsec3_get_nextowner(rrset, r, &nm, &nmlen))
return 0;
/* append zone name; the owner name must be <b32>.zone */
zone = rrset->rk.dname;
zonelen = rrset->rk.dname_len;
dname_remove_label(&zone, &zonelen);
return nsec3_hash_to_b32(nm, nmlen, zone, zonelen, buf, max);
}
int
nsec3_has_type(struct ub_packed_rrset_key* rrset, int r, uint16_t type)
{
uint8_t* bitmap;
size_t bitlen, skiplen;
struct packed_rrset_data* d = (struct packed_rrset_data*)
rrset->entry.data;
log_assert(d && r < (int)d->count);
skiplen = 2+4;
/* skip salt */
if(d->rr_len[r] < skiplen+1)
return 0; /* malformed, too short */
skiplen += 1+(size_t)d->rr_data[r][skiplen];
/* skip next hashed owner */
if(d->rr_len[r] < skiplen+1)
return 0; /* malformed, too short */
skiplen += 1+(size_t)d->rr_data[r][skiplen];
if(d->rr_len[r] < skiplen)
return 0; /* malformed, too short */
bitlen = d->rr_len[r] - skiplen;
bitmap = d->rr_data[r]+skiplen;
return nsecbitmap_has_type_rdata(bitmap, bitlen, type);
}
/**
* Iterate through NSEC3 list, per RR
* This routine gives the next RR in the list (or sets rrset null).
* Usage:
*
* size_t rrsetnum;
* int rrnum;
* struct ub_packed_rrset_key* rrset;
* for(rrset=filter_first(filter, &rrsetnum, &rrnum); rrset;
* rrset=filter_next(filter, &rrsetnum, &rrnum))
* do_stuff;
*
* Also filters out
* o unknown flag NSEC3s
* o unknown algorithm NSEC3s.
* @param filter: nsec3 filter structure.
* @param rrsetnum: in/out rrset number to look at.
* @param rrnum: in/out rr number in rrset to look at.
* @returns ptr to the next rrset (or NULL at end).
*/
static struct ub_packed_rrset_key*
filter_next(struct nsec3_filter* filter, size_t* rrsetnum, int* rrnum)
{
size_t i;
int r;
uint8_t* nm;
size_t nmlen;
if(!filter->zone) /* empty list */
return NULL;
for(i=*rrsetnum; i<filter->num; i++) {
/* see if RRset qualifies */
if(ntohs(filter->list[i]->rk.type) != LDNS_RR_TYPE_NSEC3 ||
ntohs(filter->list[i]->rk.rrset_class) !=
filter->fclass)
continue;
/* check RRset zone */
nm = filter->list[i]->rk.dname;
nmlen = filter->list[i]->rk.dname_len;
dname_remove_label(&nm, &nmlen);
if(query_dname_compare(nm, filter->zone) != 0)
continue;
if(i == *rrsetnum)
r = (*rrnum) + 1; /* continue at next RR */
else r = 0; /* new RRset start at first RR */
for(; r < (int)rrset_get_count(filter->list[i]); r++) {
/* skip unknown flags, algo */
if(nsec3_unknown_flags(filter->list[i], r) ||
!nsec3_known_algo(filter->list[i], r))
continue;
/* this one is a good target */
*rrsetnum = i;
*rrnum = r;
return filter->list[i];
}
}
return NULL;
}
/**
* Start iterating over NSEC3 records.
* @param filter: the filter structure, must have been filter_init-ed.
* @param rrsetnum: can be undefined on call, initialised.
* @param rrnum: can be undefined on call, initialised.
* @return first rrset of an NSEC3, together with rrnum this points to
* the first RR to examine. Is NULL on empty list.
*/
static struct ub_packed_rrset_key*
filter_first(struct nsec3_filter* filter, size_t* rrsetnum, int* rrnum)
{
*rrsetnum = 0;
*rrnum = -1;
return filter_next(filter, rrsetnum, rrnum);
}
/** see if at least one RR is known (flags, algo) */
static int
nsec3_rrset_has_known(struct ub_packed_rrset_key* s)
{
int r;
for(r=0; r < (int)rrset_get_count(s); r++) {
if(!nsec3_unknown_flags(s, r) && nsec3_known_algo(s, r))
return 1;
}
return 0;
}
/**
* Initialize the filter structure.
* Finds the zone by looking at available NSEC3 records and best match.
* (skips the unknown flag and unknown algo NSEC3s).
*
* @param filter: nsec3 filter structure.
* @param list: list of rrsets, an array of them.
* @param num: number of rrsets in list.
* @param qinfo:
* query name to match a zone for.
* query type (if DS a higher zone must be chosen)
* qclass, to filter NSEC3s with.
*/
static void
filter_init(struct nsec3_filter* filter, struct ub_packed_rrset_key** list,
size_t num, struct query_info* qinfo)
{
size_t i;
uint8_t* nm;
size_t nmlen;
filter->zone = NULL;
filter->zone_len = 0;
filter->list = list;
filter->num = num;
filter->fclass = qinfo->qclass;
for(i=0; i<num; i++) {
/* ignore other stuff in the list */
if(ntohs(list[i]->rk.type) != LDNS_RR_TYPE_NSEC3 ||
ntohs(list[i]->rk.rrset_class) != qinfo->qclass)
continue;
/* skip unknown flags, algo */
if(!nsec3_rrset_has_known(list[i]))
continue;
/* since NSEC3s are base32.zonename, we can find the zone
* name by stripping off the first label of the record */
nm = list[i]->rk.dname;
nmlen = list[i]->rk.dname_len;
dname_remove_label(&nm, &nmlen);
/* if we find a domain that can prove about the qname,
* and if this domain is closer to the qname */
if(dname_subdomain_c(qinfo->qname, nm) && (!filter->zone ||
dname_subdomain_c(nm, filter->zone))) {
/* for a type DS do not accept a zone equal to qname*/
if(qinfo->qtype == LDNS_RR_TYPE_DS &&
query_dname_compare(qinfo->qname, nm) == 0 &&
!dname_is_root(qinfo->qname))
continue;
filter->zone = nm;
filter->zone_len = nmlen;
}
}
}
/**
* Find max iteration count using config settings and key size
* @param ve: validator environment with iteration count config settings.
* @param bits: key size
* @return max iteration count
*/
static size_t
get_max_iter(struct val_env* ve, size_t bits)
{
int i;
log_assert(ve->nsec3_keyiter_count > 0);
/* round up to nearest config keysize, linear search, keep it small */
for(i=0; i<ve->nsec3_keyiter_count; i++) {
if(bits <= ve->nsec3_keysize[i])
return ve->nsec3_maxiter[i];
}
/* else, use value for biggest key */
return ve->nsec3_maxiter[ve->nsec3_keyiter_count-1];
}
/**
* Determine if any of the NSEC3 rrs iteration count is too high, from key.
* @param ve: validator environment with iteration count config settings.
* @param filter: what NSEC3s to loop over.
* @param kkey: key entry used for verification; used for iteration counts.
* @return 1 if some nsec3s are above the max iteration count.
*/
static int
nsec3_iteration_count_high(struct val_env* ve, struct nsec3_filter* filter,
struct key_entry_key* kkey)
{
size_t rrsetnum;
int rrnum;
struct ub_packed_rrset_key* rrset;
/* first determine the max number of iterations */
size_t bits = key_entry_keysize(kkey);
size_t max_iter = get_max_iter(ve, bits);
verbose(VERB_ALGO, "nsec3: keysize %d bits, max iterations %d",
(int)bits, (int)max_iter);
for(rrset=filter_first(filter, &rrsetnum, &rrnum); rrset;
rrset=filter_next(filter, &rrsetnum, &rrnum)) {
if(nsec3_get_iter(rrset, rrnum) > max_iter)
return 1;
}
return 0;
}
/* nsec3_cache_compare for rbtree */
int
nsec3_hash_cmp(const void* c1, const void* c2)
{
struct nsec3_cached_hash* h1 = (struct nsec3_cached_hash*)c1;
struct nsec3_cached_hash* h2 = (struct nsec3_cached_hash*)c2;
uint8_t* s1, *s2;
size_t s1len, s2len;
int c = query_dname_compare(h1->dname, h2->dname);
if(c != 0)
return c;
/* compare parameters */
/* if both malformed, its equal, robustness */
if(nsec3_get_algo(h1->nsec3, h1->rr) !=
nsec3_get_algo(h2->nsec3, h2->rr)) {
if(nsec3_get_algo(h1->nsec3, h1->rr) <
nsec3_get_algo(h2->nsec3, h2->rr))
return -1;
return 1;
}
if(nsec3_get_iter(h1->nsec3, h1->rr) !=
nsec3_get_iter(h2->nsec3, h2->rr)) {
if(nsec3_get_iter(h1->nsec3, h1->rr) <
nsec3_get_iter(h2->nsec3, h2->rr))
return -1;
return 1;
}
(void)nsec3_get_salt(h1->nsec3, h1->rr, &s1, &s1len);
(void)nsec3_get_salt(h2->nsec3, h2->rr, &s2, &s2len);
if(s1len != s2len) {
if(s1len < s2len)
return -1;
return 1;
}
return memcmp(s1, s2, s1len);
}
size_t
nsec3_get_hashed(sldns_buffer* buf, uint8_t* nm, size_t nmlen, int algo,
size_t iter, uint8_t* salt, size_t saltlen, uint8_t* res, size_t max)
{
size_t i, hash_len;
/* prepare buffer for first iteration */
sldns_buffer_clear(buf);
sldns_buffer_write(buf, nm, nmlen);
query_dname_tolower(sldns_buffer_begin(buf));
sldns_buffer_write(buf, salt, saltlen);
sldns_buffer_flip(buf);
hash_len = nsec3_hash_algo_size_supported(algo);
if(hash_len == 0) {
log_err("nsec3 hash of unknown algo %d", algo);
return 0;
}
if(hash_len > max)
return 0;
if(!secalgo_nsec3_hash(algo, (unsigned char*)sldns_buffer_begin(buf),
sldns_buffer_limit(buf), (unsigned char*)res))
return 0;
for(i=0; i<iter; i++) {
sldns_buffer_clear(buf);
sldns_buffer_write(buf, res, hash_len);
sldns_buffer_write(buf, salt, saltlen);
sldns_buffer_flip(buf);
if(!secalgo_nsec3_hash(algo,
(unsigned char*)sldns_buffer_begin(buf),
sldns_buffer_limit(buf), (unsigned char*)res))
return 0;
}
return hash_len;
}
/** perform hash of name */
static int
nsec3_calc_hash(struct regional* region, sldns_buffer* buf,
struct nsec3_cached_hash* c)
{
int algo = nsec3_get_algo(c->nsec3, c->rr);
size_t iter = nsec3_get_iter(c->nsec3, c->rr);
uint8_t* salt;
size_t saltlen, i;
if(!nsec3_get_salt(c->nsec3, c->rr, &salt, &saltlen))
return -1;
/* prepare buffer for first iteration */
sldns_buffer_clear(buf);
sldns_buffer_write(buf, c->dname, c->dname_len);
query_dname_tolower(sldns_buffer_begin(buf));
sldns_buffer_write(buf, salt, saltlen);
sldns_buffer_flip(buf);
c->hash_len = nsec3_hash_algo_size_supported(algo);
if(c->hash_len == 0) {
log_err("nsec3 hash of unknown algo %d", algo);
return -1;
}
c->hash = (uint8_t*)regional_alloc(region, c->hash_len);
if(!c->hash)
return 0;
(void)secalgo_nsec3_hash(algo, (unsigned char*)sldns_buffer_begin(buf),
sldns_buffer_limit(buf), (unsigned char*)c->hash);
for(i=0; i<iter; i++) {
sldns_buffer_clear(buf);
sldns_buffer_write(buf, c->hash, c->hash_len);
sldns_buffer_write(buf, salt, saltlen);
sldns_buffer_flip(buf);
(void)secalgo_nsec3_hash(algo,
(unsigned char*)sldns_buffer_begin(buf),
sldns_buffer_limit(buf), (unsigned char*)c->hash);
}
return 1;
}
/** perform b32 encoding of hash */
static int
nsec3_calc_b32(struct regional* region, sldns_buffer* buf,
struct nsec3_cached_hash* c)
{
int r;
sldns_buffer_clear(buf);
r = sldns_b32_ntop_extended_hex(c->hash, c->hash_len,
(char*)sldns_buffer_begin(buf), sldns_buffer_limit(buf));
if(r < 1) {
log_err("b32_ntop_extended_hex: error in encoding: %d", r);
return 0;
}
c->b32_len = (size_t)r;
c->b32 = regional_alloc_init(region, sldns_buffer_begin(buf),
c->b32_len);
if(!c->b32)
return 0;
return 1;
}
int
nsec3_hash_name(rbtree_type* table, struct regional* region, sldns_buffer* buf,
struct ub_packed_rrset_key* nsec3, int rr, uint8_t* dname,
size_t dname_len, struct nsec3_cached_hash** hash)
{
struct nsec3_cached_hash* c;
struct nsec3_cached_hash looki;
#ifdef UNBOUND_DEBUG
rbnode_type* n;
#endif
int r;
looki.node.key = &looki;
looki.nsec3 = nsec3;
looki.rr = rr;
looki.dname = dname;
looki.dname_len = dname_len;
/* lookup first in cache */
c = (struct nsec3_cached_hash*)rbtree_search(table, &looki);
if(c) {
*hash = c;
return 1;
}
/* create a new entry */
c = (struct nsec3_cached_hash*)regional_alloc(region, sizeof(*c));
if(!c) return 0;
c->node.key = c;
c->nsec3 = nsec3;
c->rr = rr;
c->dname = dname;
c->dname_len = dname_len;
r = nsec3_calc_hash(region, buf, c);
if(r != 1)
return r;
r = nsec3_calc_b32(region, buf, c);
if(r != 1)
return r;
#ifdef UNBOUND_DEBUG
n =
#else
(void)
#endif
rbtree_insert(table, &c->node);
log_assert(n); /* cannot be duplicate, just did lookup */
*hash = c;
return 1;
}
/**
* compare a label lowercased
*/
static int
label_compare_lower(uint8_t* lab1, uint8_t* lab2, size_t lablen)
{
size_t i;
for(i=0; i<lablen; i++) {
if(tolower((unsigned char)*lab1) != tolower((unsigned char)*lab2)) {
if(tolower((unsigned char)*lab1) < tolower((unsigned char)*lab2))
return -1;
return 1;
}
lab1++;
lab2++;
}
return 0;
}
/**
* Compare a hashed name with the owner name of an NSEC3 RRset.
* @param flt: filter with zone name.
* @param hash: the hashed name.
* @param s: rrset with owner name.
* @return true if matches exactly, false if not.
*/
static int
nsec3_hash_matches_owner(struct nsec3_filter* flt,
struct nsec3_cached_hash* hash, struct ub_packed_rrset_key* s)
{
uint8_t* nm = s->rk.dname;
/* compare, does hash of name based on params in this NSEC3
* match the owner name of this NSEC3?
* name must be: <hashlength>base32 . zone name
* so; first label must not be root label (not zero length),
* and match the b32 encoded hash length,
* and the label content match the b32 encoded hash
* and the rest must be the zone name.
*/
if(hash->b32_len != 0 && (size_t)nm[0] == hash->b32_len &&
label_compare_lower(nm+1, hash->b32, hash->b32_len) == 0 &&
query_dname_compare(nm+(size_t)nm[0]+1, flt->zone) == 0) {
return 1;
}
return 0;
}
/**
* Find matching NSEC3
* Find the NSEC3Record that matches a hash of a name.
* @param env: module environment with temporary region and buffer.
* @param flt: the NSEC3 RR filter, contains zone name and RRs.
* @param ct: cached hashes table.
* @param nm: name to look for.
* @param nmlen: length of name.
* @param rrset: nsec3 that matches is returned here.
* @param rr: rr number in nsec3 rrset that matches.
* @return true if a matching NSEC3 is found, false if not.
*/
static int
find_matching_nsec3(struct module_env* env, struct nsec3_filter* flt,
rbtree_type* ct, uint8_t* nm, size_t nmlen,
struct ub_packed_rrset_key** rrset, int* rr)
{
size_t i_rs;
int i_rr;
struct ub_packed_rrset_key* s;
struct nsec3_cached_hash* hash;
int r;
/* this loop skips other-zone and unknown NSEC3s, also non-NSEC3 RRs */
for(s=filter_first(flt, &i_rs, &i_rr); s;
s=filter_next(flt, &i_rs, &i_rr)) {
/* get name hashed for this NSEC3 RR */
r = nsec3_hash_name(ct, env->scratch, env->scratch_buffer,
s, i_rr, nm, nmlen, &hash);
if(r == 0) {
log_err("nsec3: malloc failure");
break; /* alloc failure */
} else if(r < 0)
continue; /* malformed NSEC3 */
else if(nsec3_hash_matches_owner(flt, hash, s)) {
*rrset = s; /* rrset with this name */
*rr = i_rr; /* matches hash with these parameters */
return 1;
}
}
*rrset = NULL;
*rr = 0;
return 0;
}
int
nsec3_covers(uint8_t* zone, struct nsec3_cached_hash* hash,
struct ub_packed_rrset_key* rrset, int rr, sldns_buffer* buf)
{
uint8_t* next, *owner;
size_t nextlen;
int len;
if(!nsec3_get_nextowner(rrset, rr, &next, &nextlen))
return 0; /* malformed RR proves nothing */
/* check the owner name is a hashed value . apex
* base32 encoded values must have equal length.
* hash_value and next hash value must have equal length. */
if(nextlen != hash->hash_len || hash->hash_len==0||hash->b32_len==0||
(size_t)*rrset->rk.dname != hash->b32_len ||
query_dname_compare(rrset->rk.dname+1+
(size_t)*rrset->rk.dname, zone) != 0)
return 0; /* bad lengths or owner name */
/* This is the "normal case: owner < next and owner < hash < next */
if(label_compare_lower(rrset->rk.dname+1, hash->b32,
hash->b32_len) < 0 &&
memcmp(hash->hash, next, nextlen) < 0)
return 1;
/* convert owner name from text to binary */
sldns_buffer_clear(buf);
owner = sldns_buffer_begin(buf);
len = sldns_b32_pton_extended_hex((char*)rrset->rk.dname+1,
hash->b32_len, owner, sldns_buffer_limit(buf));
if(len<1)
return 0; /* bad owner name in some way */
if((size_t)len != hash->hash_len || (size_t)len != nextlen)
return 0; /* wrong length */
/* this is the end of zone case: next <= owner &&
* (hash > owner || hash < next)
* this also covers the only-apex case of next==owner.
*/
if(memcmp(next, owner, nextlen) <= 0 &&
( memcmp(hash->hash, owner, nextlen) > 0 ||
memcmp(hash->hash, next, nextlen) < 0)) {
return 1;
}
return 0;
}
/**
* findCoveringNSEC3
* Given a name, find a covering NSEC3 from among a list of NSEC3s.
*
* @param env: module environment with temporary region and buffer.
* @param flt: the NSEC3 RR filter, contains zone name and RRs.
* @param ct: cached hashes table.
* @param nm: name to check if covered.
* @param nmlen: length of name.
* @param rrset: covering NSEC3 rrset is returned here.
* @param rr: rr of cover is returned here.
* @return true if a covering NSEC3 is found, false if not.
*/
static int
find_covering_nsec3(struct module_env* env, struct nsec3_filter* flt,
rbtree_type* ct, uint8_t* nm, size_t nmlen,
struct ub_packed_rrset_key** rrset, int* rr)
{
size_t i_rs;
int i_rr;
struct ub_packed_rrset_key* s;
struct nsec3_cached_hash* hash;
int r;
/* this loop skips other-zone and unknown NSEC3s, also non-NSEC3 RRs */
for(s=filter_first(flt, &i_rs, &i_rr); s;
s=filter_next(flt, &i_rs, &i_rr)) {
/* get name hashed for this NSEC3 RR */
r = nsec3_hash_name(ct, env->scratch, env->scratch_buffer,
s, i_rr, nm, nmlen, &hash);
if(r == 0) {
log_err("nsec3: malloc failure");
break; /* alloc failure */
} else if(r < 0)
continue; /* malformed NSEC3 */
else if(nsec3_covers(flt->zone, hash, s, i_rr,
env->scratch_buffer)) {
*rrset = s; /* rrset with this name */
*rr = i_rr; /* covers hash with these parameters */
return 1;
}
}
*rrset = NULL;
*rr = 0;
return 0;
}
/**
* findClosestEncloser
* Given a name and a list of NSEC3s, find the candidate closest encloser.
* This will be the first ancestor of 'name' (including itself) to have a
* matching NSEC3 RR.
* @param env: module environment with temporary region and buffer.
* @param flt: the NSEC3 RR filter, contains zone name and RRs.
* @param ct: cached hashes table.
* @param qinfo: query that is verified for.
* @param ce: closest encloser information is returned in here.
* @return true if a closest encloser candidate is found, false if not.
*/
static int
nsec3_find_closest_encloser(struct module_env* env, struct nsec3_filter* flt,
rbtree_type* ct, struct query_info* qinfo, struct ce_response* ce)
{
uint8_t* nm = qinfo->qname;
size_t nmlen = qinfo->qname_len;
/* This scans from longest name to shortest, so the first match
* we find is the only viable candidate. */
/* (David:) FIXME: modify so that the NSEC3 matching the zone apex need
* not be present. (Mark Andrews idea).
* (Wouter:) But make sure you check for DNAME bit in zone apex,
* if the NSEC3 you find is the only NSEC3 in the zone, then this
* may be the case. */
while(dname_subdomain_c(nm, flt->zone)) {
if(find_matching_nsec3(env, flt, ct, nm, nmlen,
&ce->ce_rrset, &ce->ce_rr)) {
ce->ce = nm;
ce->ce_len = nmlen;
return 1;
}
dname_remove_label(&nm, &nmlen);
}
return 0;
}
/**
* Given a qname and its proven closest encloser, calculate the "next
* closest" name. Basically, this is the name that is one label longer than
* the closest encloser that is still a subdomain of qname.
*
* @param qname: query name.
* @param qnamelen: length of qname.
* @param ce: closest encloser
* @param nm: result name.
* @param nmlen: length of nm.
*/
static void
next_closer(uint8_t* qname, size_t qnamelen, uint8_t* ce,
uint8_t** nm, size_t* nmlen)
{
int strip = dname_count_labels(qname) - dname_count_labels(ce) -1;
*nm = qname;
*nmlen = qnamelen;
if(strip>0)
dname_remove_labels(nm, nmlen, strip);
}
/**
* proveClosestEncloser
* Given a List of nsec3 RRs, find and prove the closest encloser to qname.
* @param env: module environment with temporary region and buffer.
* @param flt: the NSEC3 RR filter, contains zone name and RRs.
* @param ct: cached hashes table.
* @param qinfo: query that is verified for.
* @param prove_does_not_exist: If true, then if the closest encloser
* turns out to be qname, then null is returned.
* If set true, and the return value is true, then you can be
* certain that the ce.nc_rrset and ce.nc_rr are set properly.
* @param ce: closest encloser information is returned in here.
* @return bogus if no closest encloser could be proven.
* secure if a closest encloser could be proven, ce is set.
* insecure if the closest-encloser candidate turns out to prove
* that an insecure delegation exists above the qname.
*/
static enum sec_status
nsec3_prove_closest_encloser(struct module_env* env, struct nsec3_filter* flt,
rbtree_type* ct, struct query_info* qinfo, int prove_does_not_exist,
struct ce_response* ce)
{
uint8_t* nc;
size_t nc_len;
/* robust: clean out ce, in case it gets abused later */
memset(ce, 0, sizeof(*ce));
if(!nsec3_find_closest_encloser(env, flt, ct, qinfo, ce)) {
verbose(VERB_ALGO, "nsec3 proveClosestEncloser: could "
"not find a candidate for the closest encloser.");
return sec_status_bogus;
}
log_nametypeclass(VERB_ALGO, "ce candidate", ce->ce, 0, 0);
if(query_dname_compare(ce->ce, qinfo->qname) == 0) {
if(prove_does_not_exist) {
verbose(VERB_ALGO, "nsec3 proveClosestEncloser: "
"proved that qname existed, bad");
return sec_status_bogus;
}
/* otherwise, we need to nothing else to prove that qname
* is its own closest encloser. */
return sec_status_secure;
}
/* If the closest encloser is actually a delegation, then the
* response should have been a referral. If it is a DNAME, then
* it should have been a DNAME response. */
if(nsec3_has_type(ce->ce_rrset, ce->ce_rr, LDNS_RR_TYPE_NS) &&
!nsec3_has_type(ce->ce_rrset, ce->ce_rr, LDNS_RR_TYPE_SOA)) {
if(!nsec3_has_type(ce->ce_rrset, ce->ce_rr, LDNS_RR_TYPE_DS)) {
verbose(VERB_ALGO, "nsec3 proveClosestEncloser: "
"closest encloser is insecure delegation");
return sec_status_insecure;
}
verbose(VERB_ALGO, "nsec3 proveClosestEncloser: closest "
"encloser was a delegation, bad");
return sec_status_bogus;
}
if(nsec3_has_type(ce->ce_rrset, ce->ce_rr, LDNS_RR_TYPE_DNAME)) {
verbose(VERB_ALGO, "nsec3 proveClosestEncloser: closest "
"encloser was a DNAME, bad");
return sec_status_bogus;
}
/* Otherwise, we need to show that the next closer name is covered. */
next_closer(qinfo->qname, qinfo->qname_len, ce->ce, &nc, &nc_len);
if(!find_covering_nsec3(env, flt, ct, nc, nc_len,
&ce->nc_rrset, &ce->nc_rr)) {
verbose(VERB_ALGO, "nsec3: Could not find proof that the "
"candidate encloser was the closest encloser");
return sec_status_bogus;
}
return sec_status_secure;
}
/** allocate a wildcard for the closest encloser */
static uint8_t*
nsec3_ce_wildcard(struct regional* region, uint8_t* ce, size_t celen,
size_t* len)
{
uint8_t* nm;
if(celen > LDNS_MAX_DOMAINLEN - 2)
return 0; /* too long */
nm = (uint8_t*)regional_alloc(region, celen+2);
if(!nm) {
log_err("nsec3 wildcard: out of memory");
return 0; /* alloc failure */
}
nm[0] = 1;
nm[1] = (uint8_t)'*'; /* wildcard label */
memmove(nm+2, ce, celen);
*len = celen+2;
return nm;
}
/** Do the name error proof */
static enum sec_status
nsec3_do_prove_nameerror(struct module_env* env, struct nsec3_filter* flt,
rbtree_type* ct, struct query_info* qinfo)
{
struct ce_response ce;
uint8_t* wc;
size_t wclen;
struct ub_packed_rrset_key* wc_rrset;
int wc_rr;
enum sec_status sec;
/* First locate and prove the closest encloser to qname. We will
* use the variant that fails if the closest encloser turns out
* to be qname. */
sec = nsec3_prove_closest_encloser(env, flt, ct, qinfo, 1, &ce);
if(sec != sec_status_secure) {
if(sec == sec_status_bogus)
verbose(VERB_ALGO, "nsec3 nameerror proof: failed "
"to prove a closest encloser");
else verbose(VERB_ALGO, "nsec3 nameerror proof: closest "
"nsec3 is an insecure delegation");
return sec;
}
log_nametypeclass(VERB_ALGO, "nsec3 namerror: proven ce=", ce.ce,0,0);
/* At this point, we know that qname does not exist. Now we need
* to prove that the wildcard does not exist. */
log_assert(ce.ce);
wc = nsec3_ce_wildcard(env->scratch, ce.ce, ce.ce_len, &wclen);
if(!wc || !find_covering_nsec3(env, flt, ct, wc, wclen,
&wc_rrset, &wc_rr)) {
verbose(VERB_ALGO, "nsec3 nameerror proof: could not prove "
"that the applicable wildcard did not exist.");
return sec_status_bogus;
}
if(ce.nc_rrset && nsec3_has_optout(ce.nc_rrset, ce.nc_rr)) {
verbose(VERB_ALGO, "nsec3 nameerror proof: nc has optout");
return sec_status_insecure;
}
return sec_status_secure;
}
enum sec_status
nsec3_prove_nameerror(struct module_env* env, struct val_env* ve,
struct ub_packed_rrset_key** list, size_t num,
struct query_info* qinfo, struct key_entry_key* kkey)
{
rbtree_type ct;
struct nsec3_filter flt;
if(!list || num == 0 || !kkey || !key_entry_isgood(kkey))
return sec_status_bogus; /* no valid NSEC3s, bogus */
rbtree_init(&ct, &nsec3_hash_cmp); /* init names-to-hash cache */
filter_init(&flt, list, num, qinfo); /* init RR iterator */
if(!flt.zone)
return sec_status_bogus; /* no RRs */
if(nsec3_iteration_count_high(ve, &flt, kkey))
return sec_status_insecure; /* iteration count too high */
log_nametypeclass(VERB_ALGO, "start nsec3 nameerror proof, zone",
flt.zone, 0, 0);
return nsec3_do_prove_nameerror(env, &flt, &ct, qinfo);
}
/*
* No code to handle qtype=NSEC3 specially.
* This existed in early drafts, but was later (-05) removed.
*/
/** Do the nodata proof */
static enum sec_status
nsec3_do_prove_nodata(struct module_env* env, struct nsec3_filter* flt,
rbtree_type* ct, struct query_info* qinfo)
{
struct ce_response ce;
uint8_t* wc;
size_t wclen;
struct ub_packed_rrset_key* rrset;
int rr;
enum sec_status sec;
if(find_matching_nsec3(env, flt, ct, qinfo->qname, qinfo->qname_len,
&rrset, &rr)) {
/* cases 1 and 2 */
if(nsec3_has_type(rrset, rr, qinfo->qtype)) {
verbose(VERB_ALGO, "proveNodata: Matching NSEC3 "
"proved that type existed, bogus");
return sec_status_bogus;
} else if(nsec3_has_type(rrset, rr, LDNS_RR_TYPE_CNAME)) {
verbose(VERB_ALGO, "proveNodata: Matching NSEC3 "
"proved that a CNAME existed, bogus");
return sec_status_bogus;
}
/*
* If type DS: filter_init zone find already found a parent
* zone, so this nsec3 is from a parent zone.
* o can be not a delegation (unusual query for normal name,
* no DS anyway, but we can verify that).
* o can be a delegation (which is the usual DS check).
* o may not have the SOA bit set (only the top of the
* zone, which must have been above the name, has that).
* Except for the root; which is checked by itself.
*
* If not type DS: matching nsec3 must not be a delegation.
*/
if(qinfo->qtype == LDNS_RR_TYPE_DS && qinfo->qname_len != 1
&& nsec3_has_type(rrset, rr, LDNS_RR_TYPE_SOA) &&
!dname_is_root(qinfo->qname)) {
verbose(VERB_ALGO, "proveNodata: apex NSEC3 "
"abused for no DS proof, bogus");
return sec_status_bogus;
} else if(qinfo->qtype != LDNS_RR_TYPE_DS &&
nsec3_has_type(rrset, rr, LDNS_RR_TYPE_NS) &&
!nsec3_has_type(rrset, rr, LDNS_RR_TYPE_SOA)) {
if(!nsec3_has_type(rrset, rr, LDNS_RR_TYPE_DS)) {
verbose(VERB_ALGO, "proveNodata: matching "
"NSEC3 is insecure delegation");
return sec_status_insecure;
}
verbose(VERB_ALGO, "proveNodata: matching "
"NSEC3 is a delegation, bogus");
return sec_status_bogus;
}
return sec_status_secure;
}
/* For cases 3 - 5, we need the proven closest encloser, and it
* can't match qname. Although, at this point, we know that it
* won't since we just checked that. */
sec = nsec3_prove_closest_encloser(env, flt, ct, qinfo, 1, &ce);
if(sec == sec_status_bogus) {
verbose(VERB_ALGO, "proveNodata: did not match qname, "
"nor found a proven closest encloser.");
return sec_status_bogus;
} else if(sec==sec_status_insecure && qinfo->qtype!=LDNS_RR_TYPE_DS){
verbose(VERB_ALGO, "proveNodata: closest nsec3 is insecure "
"delegation.");
return sec_status_insecure;
}
/* Case 3: removed */
/* Case 4: */
log_assert(ce.ce);
wc = nsec3_ce_wildcard(env->scratch, ce.ce, ce.ce_len, &wclen);
if(wc && find_matching_nsec3(env, flt, ct, wc, wclen, &rrset, &rr)) {
/* found wildcard */
if(nsec3_has_type(rrset, rr, qinfo->qtype)) {
verbose(VERB_ALGO, "nsec3 nodata proof: matching "
"wildcard had qtype, bogus");
return sec_status_bogus;
} else if(nsec3_has_type(rrset, rr, LDNS_RR_TYPE_CNAME)) {
verbose(VERB_ALGO, "nsec3 nodata proof: matching "
"wildcard had a CNAME, bogus");
return sec_status_bogus;
}
if(qinfo->qtype == LDNS_RR_TYPE_DS && qinfo->qname_len != 1
&& nsec3_has_type(rrset, rr, LDNS_RR_TYPE_SOA)) {
verbose(VERB_ALGO, "nsec3 nodata proof: matching "
"wildcard for no DS proof has a SOA, bogus");
return sec_status_bogus;
} else if(qinfo->qtype != LDNS_RR_TYPE_DS &&
nsec3_has_type(rrset, rr, LDNS_RR_TYPE_NS) &&
!nsec3_has_type(rrset, rr, LDNS_RR_TYPE_SOA)) {
verbose(VERB_ALGO, "nsec3 nodata proof: matching "
"wildcard is a delegation, bogus");
return sec_status_bogus;
}
/* everything is peachy keen, except for optout spans */
if(ce.nc_rrset && nsec3_has_optout(ce.nc_rrset, ce.nc_rr)) {
verbose(VERB_ALGO, "nsec3 nodata proof: matching "
"wildcard is in optout range, insecure");
return sec_status_insecure;
}
return sec_status_secure;
}
/* Case 5: */
/* Due to forwarders, cnames, and other collating effects, we
* can see the ordinary unsigned data from a zone beneath an
* insecure delegation under an optout here */
if(!ce.nc_rrset) {
verbose(VERB_ALGO, "nsec3 nodata proof: no next closer nsec3");
return sec_status_bogus;
}
/* We need to make sure that the covering NSEC3 is opt-out. */
log_assert(ce.nc_rrset);
if(!nsec3_has_optout(ce.nc_rrset, ce.nc_rr)) {
if(qinfo->qtype == LDNS_RR_TYPE_DS)
verbose(VERB_ALGO, "proveNodata: covering NSEC3 was not "
"opt-out in an opt-out DS NOERROR/NODATA case.");
else verbose(VERB_ALGO, "proveNodata: could not find matching "
"NSEC3, nor matching wildcard, nor optout NSEC3 "
"-- no more options, bogus.");
return sec_status_bogus;
}
/* RFC5155 section 9.2: if nc has optout then no AD flag set */
return sec_status_insecure;
}
enum sec_status
nsec3_prove_nodata(struct module_env* env, struct val_env* ve,
struct ub_packed_rrset_key** list, size_t num,
struct query_info* qinfo, struct key_entry_key* kkey)
{
rbtree_type ct;
struct nsec3_filter flt;
if(!list || num == 0 || !kkey || !key_entry_isgood(kkey))
return sec_status_bogus; /* no valid NSEC3s, bogus */
rbtree_init(&ct, &nsec3_hash_cmp); /* init names-to-hash cache */
filter_init(&flt, list, num, qinfo); /* init RR iterator */
if(!flt.zone)
return sec_status_bogus; /* no RRs */
if(nsec3_iteration_count_high(ve, &flt, kkey))
return sec_status_insecure; /* iteration count too high */
return nsec3_do_prove_nodata(env, &flt, &ct, qinfo);
}
enum sec_status
nsec3_prove_wildcard(struct module_env* env, struct val_env* ve,
struct ub_packed_rrset_key** list, size_t num,
struct query_info* qinfo, struct key_entry_key* kkey, uint8_t* wc)
{
rbtree_type ct;
struct nsec3_filter flt;
struct ce_response ce;
uint8_t* nc;
size_t nc_len;
size_t wclen;
(void)dname_count_size_labels(wc, &wclen);
if(!list || num == 0 || !kkey || !key_entry_isgood(kkey))
return sec_status_bogus; /* no valid NSEC3s, bogus */
rbtree_init(&ct, &nsec3_hash_cmp); /* init names-to-hash cache */
filter_init(&flt, list, num, qinfo); /* init RR iterator */
if(!flt.zone)
return sec_status_bogus; /* no RRs */
if(nsec3_iteration_count_high(ve, &flt, kkey))
return sec_status_insecure; /* iteration count too high */
/* We know what the (purported) closest encloser is by just
* looking at the supposed generating wildcard.
* The *. has already been removed from the wc name.
*/
memset(&ce, 0, sizeof(ce));
ce.ce = wc;
ce.ce_len = wclen;
/* Now we still need to prove that the original data did not exist.
* Otherwise, we need to show that the next closer name is covered. */
next_closer(qinfo->qname, qinfo->qname_len, ce.ce, &nc, &nc_len);
if(!find_covering_nsec3(env, &flt, &ct, nc, nc_len,
&ce.nc_rrset, &ce.nc_rr)) {
verbose(VERB_ALGO, "proveWildcard: did not find a covering "
"NSEC3 that covered the next closer name.");
return sec_status_bogus;
}
if(ce.nc_rrset && nsec3_has_optout(ce.nc_rrset, ce.nc_rr)) {
verbose(VERB_ALGO, "proveWildcard: NSEC3 optout");
return sec_status_insecure;
}
return sec_status_secure;
}
/** test if list is all secure */
static int
list_is_secure(struct module_env* env, struct val_env* ve,
struct ub_packed_rrset_key** list, size_t num,
struct key_entry_key* kkey, char** reason)
{
struct packed_rrset_data* d;
size_t i;
for(i=0; i<num; i++) {
d = (struct packed_rrset_data*)list[i]->entry.data;
if(list[i]->rk.type != htons(LDNS_RR_TYPE_NSEC3))
continue;
if(d->security == sec_status_secure)
continue;
rrset_check_sec_status(env->rrset_cache, list[i], *env->now);
if(d->security == sec_status_secure)
continue;
d->security = val_verify_rrset_entry(env, ve, list[i], kkey,
reason);
if(d->security != sec_status_secure) {
verbose(VERB_ALGO, "NSEC3 did not verify");
return 0;
}
rrset_update_sec_status(env->rrset_cache, list[i], *env->now);
}
return 1;
}
enum sec_status
nsec3_prove_nods(struct module_env* env, struct val_env* ve,
struct ub_packed_rrset_key** list, size_t num,
struct query_info* qinfo, struct key_entry_key* kkey, char** reason)
{
rbtree_type ct;
struct nsec3_filter flt;
struct ce_response ce;
struct ub_packed_rrset_key* rrset;
int rr;
log_assert(qinfo->qtype == LDNS_RR_TYPE_DS);
if(!list || num == 0 || !kkey || !key_entry_isgood(kkey)) {
*reason = "no valid NSEC3s";
return sec_status_bogus; /* no valid NSEC3s, bogus */
}
if(!list_is_secure(env, ve, list, num, kkey, reason))
return sec_status_bogus; /* not all NSEC3 records secure */
rbtree_init(&ct, &nsec3_hash_cmp); /* init names-to-hash cache */
filter_init(&flt, list, num, qinfo); /* init RR iterator */
if(!flt.zone) {
*reason = "no NSEC3 records";
return sec_status_bogus; /* no RRs */
}
if(nsec3_iteration_count_high(ve, &flt, kkey))
return sec_status_insecure; /* iteration count too high */
/* Look for a matching NSEC3 to qname -- this is the normal
* NODATA case. */
if(find_matching_nsec3(env, &flt, &ct, qinfo->qname, qinfo->qname_len,
&rrset, &rr)) {
/* If the matching NSEC3 has the SOA bit set, it is from
* the wrong zone (the child instead of the parent). If
* it has the DS bit set, then we were lied to. */
if(nsec3_has_type(rrset, rr, LDNS_RR_TYPE_SOA) &&
qinfo->qname_len != 1) {
verbose(VERB_ALGO, "nsec3 provenods: NSEC3 is from"
" child zone, bogus");
*reason = "NSEC3 from child zone";
return sec_status_bogus;
} else if(nsec3_has_type(rrset, rr, LDNS_RR_TYPE_DS)) {
verbose(VERB_ALGO, "nsec3 provenods: NSEC3 has qtype"
" DS, bogus");
*reason = "NSEC3 has DS in bitmap";
return sec_status_bogus;
}
/* If the NSEC3 RR doesn't have the NS bit set, then
* this wasn't a delegation point. */
if(!nsec3_has_type(rrset, rr, LDNS_RR_TYPE_NS))
return sec_status_indeterminate;
/* Otherwise, this proves no DS. */
return sec_status_secure;
}
/* Otherwise, we are probably in the opt-out case. */
if(nsec3_prove_closest_encloser(env, &flt, &ct, qinfo, 1, &ce)
!= sec_status_secure) {
/* an insecure delegation *above* the qname does not prove
* anything about this qname exactly, and bogus is bogus */
verbose(VERB_ALGO, "nsec3 provenods: did not match qname, "
"nor found a proven closest encloser.");
*reason = "no NSEC3 closest encloser";
return sec_status_bogus;
}
/* robust extra check */
if(!ce.nc_rrset) {
verbose(VERB_ALGO, "nsec3 nods proof: no next closer nsec3");
*reason = "no NSEC3 next closer";
return sec_status_bogus;
}
/* we had the closest encloser proof, then we need to check that the
* covering NSEC3 was opt-out -- the proveClosestEncloser step already
* checked to see if the closest encloser was a delegation or DNAME.
*/
log_assert(ce.nc_rrset);
if(!nsec3_has_optout(ce.nc_rrset, ce.nc_rr)) {
verbose(VERB_ALGO, "nsec3 provenods: covering NSEC3 was not "
"opt-out in an opt-out DS NOERROR/NODATA case.");
*reason = "covering NSEC3 was not opt-out in an opt-out "
"DS NOERROR/NODATA case";
return sec_status_bogus;
}
/* RFC5155 section 9.2: if nc has optout then no AD flag set */
return sec_status_insecure;
}
enum sec_status
nsec3_prove_nxornodata(struct module_env* env, struct val_env* ve,
struct ub_packed_rrset_key** list, size_t num,
struct query_info* qinfo, struct key_entry_key* kkey, int* nodata)
{
enum sec_status sec, secnx;
rbtree_type ct;
struct nsec3_filter flt;
*nodata = 0;
if(!list || num == 0 || !kkey || !key_entry_isgood(kkey))
return sec_status_bogus; /* no valid NSEC3s, bogus */
rbtree_init(&ct, &nsec3_hash_cmp); /* init names-to-hash cache */
filter_init(&flt, list, num, qinfo); /* init RR iterator */
if(!flt.zone)
return sec_status_bogus; /* no RRs */
if(nsec3_iteration_count_high(ve, &flt, kkey))
return sec_status_insecure; /* iteration count too high */
/* try nxdomain and nodata after another, while keeping the
* hash cache intact */
secnx = nsec3_do_prove_nameerror(env, &flt, &ct, qinfo);
if(secnx==sec_status_secure)
return sec_status_secure;
sec = nsec3_do_prove_nodata(env, &flt, &ct, qinfo);
if(sec==sec_status_secure) {
*nodata = 1;
} else if(sec == sec_status_insecure) {
*nodata = 1;
} else if(secnx == sec_status_insecure) {
sec = sec_status_insecure;
}
return sec;
}