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/* Copyright (C) 2014-2017 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#include <contrib/cleanup.h>
#include <libknot/descriptor.h>
#include <libknot/rdataset.h>
#include <libknot/rrset.h>
#include <libknot/packet/wire.h>
#include <libdnssec/key.h>
#include <libdnssec/error.h>
#include "lib/defines.h"
#include "lib/dnssec.h"
#include "lib/dnssec/ta.h"
#include "lib/resolve.h"
#include "lib/utils.h"
knot_rrset_t *kr_ta_get(map_t *trust_anchors, const knot_dname_t *name)
{
return map_get(trust_anchors, (const char *)name);
}
const knot_dname_t *kr_ta_get_longest_name(map_t *trust_anchors, const knot_dname_t *name)
{
while(name) {
if (kr_ta_get(trust_anchors, name)) {
return name;
}
if (name[0] == '\0') {
break;
}
name = knot_wire_next_label(name, NULL);
}
return NULL;
}
/* @internal Create DS from DNSKEY, caller MUST free dst if successful. */
static int dnskey2ds(dnssec_binary_t *dst, const knot_dname_t *owner, const uint8_t *rdata, uint16_t rdlen)
{
dnssec_key_t *key = NULL;
int ret = dnssec_key_new(&key);
if (ret) goto cleanup;
/* Create DS from DNSKEY and reinsert */
const dnssec_binary_t key_data = { .size = rdlen, .data = (uint8_t *)rdata };
ret = dnssec_key_set_rdata(key, &key_data);
if (ret) goto cleanup;
/* Accept only keys with Zone and SEP flags that aren't revoked,
* as a precaution. RFC 5011 also utilizes these flags.
* TODO: kr_dnssec_key_* names are confusing. */
const bool flags_ok = kr_dnssec_key_zsk(rdata) && !kr_dnssec_key_revoked(rdata);
if (!flags_ok) {
auto_free char *owner_str = kr_dname_text(owner);
kr_log_error("[ ta ] refusing to trust %s DNSKEY because of flags %d\n",
owner_str, dnssec_key_get_flags(key));
ret = kr_error(EILSEQ);
goto cleanup;
} else if (!kr_dnssec_key_ksk(rdata)) {
auto_free char *owner_str = kr_dname_text(owner);
int flags = dnssec_key_get_flags(key);
kr_log_info("[ ta ] warning: %s DNSKEY is missing the SEP bit; "
"flags %d instead of %d\n",
owner_str, flags, flags + 1/*a little ugly*/);
}
ret = dnssec_key_set_dname(key, owner);
if (ret) goto cleanup;
ret = dnssec_key_create_ds(key, DNSSEC_KEY_DIGEST_SHA256, dst);
cleanup:
dnssec_key_free(key);
return kr_error(ret);
}
/* @internal Insert new TA to trust anchor set, rdata MUST be of DS type. */
static int insert_ta(map_t *trust_anchors, const knot_dname_t *name,
uint32_t ttl, const uint8_t *rdata, uint16_t rdlen)
{
bool is_new_key = false;
knot_rrset_t *ta_rr = kr_ta_get(trust_anchors, name);
if (!ta_rr) {
ta_rr = knot_rrset_new(name, KNOT_RRTYPE_DS, KNOT_CLASS_IN, ttl, NULL);
is_new_key = true;
}
/* Merge-in new key data */
if (!ta_rr || (rdlen > 0 && knot_rrset_add_rdata(ta_rr, rdata, rdlen, NULL) != 0)) {
knot_rrset_free(ta_rr, NULL);
return kr_error(ENOMEM);
}
if (is_new_key) {
return map_set(trust_anchors, (const char *)name, ta_rr);
}
return kr_ok();
}
int kr_ta_add(map_t *trust_anchors, const knot_dname_t *name, uint16_t type,
uint32_t ttl, const uint8_t *rdata, uint16_t rdlen)
{
if (!trust_anchors || !name) {
return kr_error(EINVAL);
}
/* DS/DNSEY types are accepted, for DNSKEY we
* need to compute a DS digest. */
if (type == KNOT_RRTYPE_DS) {
return insert_ta(trust_anchors, name, ttl, rdata, rdlen);
} else if (type == KNOT_RRTYPE_DNSKEY) {
dnssec_binary_t ds_rdata = { 0, };
int ret = dnskey2ds(&ds_rdata, name, rdata, rdlen);
if (ret != 0) {
return ret;
}
ret = insert_ta(trust_anchors, name, ttl, ds_rdata.data, ds_rdata.size);
dnssec_binary_free(&ds_rdata);
return ret;
} else { /* Invalid type for TA */
return kr_error(EINVAL);
}
}
int kr_ta_covers(map_t *trust_anchors, const knot_dname_t *name)
{
while(name) {
if (kr_ta_get(trust_anchors, name)) {
return true;
}
if (name[0] == '\0') {
return false;
}
name = knot_wire_next_label(name, NULL);
}
return false;
}
bool kr_ta_covers_qry(struct kr_context *ctx, const knot_dname_t *name,
const uint16_t type)
{
assert(ctx && name);
if (type == KNOT_RRTYPE_DS && name[0] != '\0') {
/* DS is parent-side record, so the parent name needs to be covered. */
name = knot_wire_next_label(name, NULL);
if (!name) {
assert(false);
return false;
}
}
return kr_ta_covers(&ctx->trust_anchors, name)
&& !kr_ta_covers(&ctx->negative_anchors, name);
}
/* Delete record data */
static int del_record(const char *k, void *v, void *ext)
{
knot_rrset_t *ta_rr = v;
if (ta_rr) {
knot_rrset_free(ta_rr, NULL);
}
return 0;
}
int kr_ta_del(map_t *trust_anchors, const knot_dname_t *name)
{
knot_rrset_t *ta_rr = kr_ta_get(trust_anchors, name);
if (ta_rr) {
del_record(NULL, ta_rr, NULL);
map_del(trust_anchors, (const char *)name);
}
return kr_ok();
}
void kr_ta_clear(map_t *trust_anchors)
{
map_walk(trust_anchors, del_record, NULL);
map_clear(trust_anchors);
}
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