0d2cd47617
When doing DNSSEC lookups we need to know one or more DS or DNSKEY RRs as trust anchors to validate lookups. With this change we add a compiled-in trust anchor database, serving the root DS key as of today, retrieved from: https://data.iana.org/root-anchors/root-anchors.xml The interface is kept generic, so that additional DS or DNSKEY RRs may be served via the same interface, for example by provisioning them locally in external files to support "islands" of security. The trust anchor database becomes the fourth source of RRs we maintain, besides, the network, the local cache, and the local zone.
102 lines
3.1 KiB
C
102 lines
3.1 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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/***
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This file is part of systemd.
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Copyright 2015 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include "alloc-util.h"
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#include "resolved-dns-trust-anchor.h"
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/* The DS RR from https://data.iana.org/root-anchors/root-anchors.xml */
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static const uint8_t root_digest[] =
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{ 0x49, 0xAA, 0xC1, 0x1D, 0x7B, 0x6F, 0x64, 0x46, 0x70, 0x2E, 0x54, 0xA1, 0x60, 0x73, 0x71, 0x60,
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0x7A, 0x1A, 0x41, 0x85, 0x52, 0x00, 0xFD, 0x2C, 0xE1, 0xCD, 0xDE, 0x32, 0xF2, 0x4E, 0x8F, 0xB5 };
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int dns_trust_anchor_load(DnsTrustAnchor *d) {
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_cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
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_cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
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int r;
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assert(d);
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r = hashmap_ensure_allocated(&d->by_key, &dns_resource_key_hash_ops);
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if (r < 0)
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return r;
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if (hashmap_get(d->by_key, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN, DNS_TYPE_DS, ".")))
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return 0;
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/* Add the RR from https://data.iana.org/root-anchors/root-anchors.xml */
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rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_DS, "");
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if (!rr)
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return -ENOMEM;
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rr->ds.key_tag = 19036;
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rr->ds.algorithm = DNSSEC_ALGORITHM_RSASHA256;
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rr->ds.digest_type = DNSSEC_DIGEST_SHA256;
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rr->ds.digest_size = sizeof(root_digest);
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rr->ds.digest = memdup(root_digest, rr->ds.digest_size);
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if (!rr->ds.digest)
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return -ENOMEM;
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answer = dns_answer_new(1);
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if (!answer)
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return -ENOMEM;
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r = dns_answer_add(answer, rr, 0);
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if (r < 0)
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return r;
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r = hashmap_put(d->by_key, rr->key, answer);
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if (r < 0)
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return r;
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answer = NULL;
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return 0;
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}
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void dns_trust_anchor_flush(DnsTrustAnchor *d) {
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DnsAnswer *a;
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assert(d);
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while ((a = hashmap_steal_first(d->by_key)))
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dns_answer_unref(a);
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d->by_key = hashmap_free(d->by_key);
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}
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int dns_trust_anchor_lookup(DnsTrustAnchor *d, DnsResourceKey *key, DnsAnswer **ret) {
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DnsAnswer *a;
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assert(d);
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assert(key);
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assert(ret);
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/* We only serve DS and DNSKEY RRs. */
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if (!IN_SET(key->type, DNS_TYPE_DS, DNS_TYPE_DNSKEY))
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return 0;
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a = hashmap_get(d->by_key, key);
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if (!a)
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return 0;
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*ret = dns_answer_ref(a);
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return 1;
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}
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