408 lines
14 KiB
C
408 lines
14 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 "conf-files.h"
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#include "def.h"
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#include "dns-domain.h"
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#include "fd-util.h"
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#include "fileio.h"
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#include "hexdecoct.h"
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#include "parse-util.h"
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#include "resolved-dns-trust-anchor.h"
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#include "set.h"
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#include "string-util.h"
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#include "strv.h"
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static const char trust_anchor_dirs[] = CONF_PATHS_NULSTR("systemd/dnssec-trust-anchors.d");
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/* The DS RR from https://data.iana.org/root-anchors/root-anchors.xml, retrieved December 2015 */
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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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static int dns_trust_anchor_add_builtin(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->positive_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->positive_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, DNS_ANSWER_AUTHENTICATED);
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if (r < 0)
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return r;
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r = hashmap_put(d->positive_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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static int dns_trust_anchor_load_positive(DnsTrustAnchor *d, const char *path, unsigned line, const char *s) {
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_cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
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_cleanup_free_ char *domain = NULL, *class = NULL, *type = NULL;
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_cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
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DnsAnswer *old_answer = NULL;
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const char *p = s;
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int r;
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assert(d);
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assert(line);
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r = extract_first_word(&p, &domain, NULL, EXTRACT_QUOTES);
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if (r < 0)
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return log_warning_errno(r, "Unable to parse domain in line %s:%u: %m", path, line);
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if (!dns_name_is_valid(domain)) {
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log_warning("Domain name %s is invalid, at line %s:%u, ignoring line.", domain, path, line);
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return -EINVAL;
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}
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r = extract_many_words(&p, NULL, 0, &class, &type, NULL);
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if (r < 0)
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return log_warning_errno(r, "Unable to parse class and type in line %s:%u: %m", path, line);
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if (r != 2) {
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log_warning("Missing class or type in line %s:%u", path, line);
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return -EINVAL;
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}
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if (!strcaseeq(class, "IN")) {
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log_warning("RR class %s is not supported, ignoring line %s:%u.", class, path, line);
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return -EINVAL;
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}
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if (strcaseeq(type, "DS")) {
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_cleanup_free_ char *key_tag = NULL, *algorithm = NULL, *digest_type = NULL, *digest = NULL;
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_cleanup_free_ void *dd = NULL;
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uint16_t kt;
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int a, dt;
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size_t l;
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r = extract_many_words(&p, NULL, 0, &key_tag, &algorithm, &digest_type, &digest, NULL);
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if (r < 0) {
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log_warning_errno(r, "Failed to parse DS parameters on line %s:%u: %m", path, line);
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return -EINVAL;
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}
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if (r != 4) {
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log_warning("Missing DS parameters on line %s:%u", path, line);
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return -EINVAL;
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}
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r = safe_atou16(key_tag, &kt);
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if (r < 0)
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return log_warning_errno(r, "Failed to parse DS key tag %s on line %s:%u: %m", key_tag, path, line);
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a = dnssec_algorithm_from_string(algorithm);
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if (a < 0) {
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log_warning("Failed to parse DS algorithm %s on line %s:%u", algorithm, path, line);
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return -EINVAL;
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}
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dt = dnssec_digest_from_string(digest_type);
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if (dt < 0) {
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log_warning("Failed to parse DS digest type %s on line %s:%u", digest_type, path, line);
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return -EINVAL;
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}
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r = unhexmem(digest, strlen(digest), &dd, &l);
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if (r < 0) {
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log_warning("Failed to parse DS digest %s on line %s:%u", digest, path, line);
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return -EINVAL;
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}
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rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_DS, domain);
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if (!rr)
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return log_oom();
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rr->ds.key_tag = kt;
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rr->ds.algorithm = a;
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rr->ds.digest_type = dt;
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rr->ds.digest_size = l;
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rr->ds.digest = dd;
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dd = NULL;
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} else if (strcaseeq(type, "DNSKEY")) {
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_cleanup_free_ char *flags = NULL, *protocol = NULL, *algorithm = NULL, *key = NULL;
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_cleanup_free_ void *k = NULL;
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uint16_t f;
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size_t l;
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int a;
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r = extract_many_words(&p, NULL, 0, &flags, &protocol, &algorithm, &key, NULL);
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if (r < 0)
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return log_warning_errno(r, "Failed to parse DNSKEY parameters on line %s:%u: %m", path, line);
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if (r != 4) {
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log_warning("Missing DNSKEY parameters on line %s:%u", path, line);
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return -EINVAL;
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}
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if (!streq(protocol, "3")) {
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log_warning("DNSKEY Protocol is not 3 on line %s:%u", path, line);
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return -EINVAL;
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}
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r = safe_atou16(flags, &f);
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if (r < 0)
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return log_warning_errno(r, "Failed to parse DNSKEY flags field %s on line %s:%u", flags, path, line);
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a = dnssec_algorithm_from_string(algorithm);
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if (a < 0) {
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log_warning("Failed to parse DNSKEY algorithm %s on line %s:%u", algorithm, path, line);
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return -EINVAL;
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}
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r = unbase64mem(key, strlen(key), &k, &l);
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if (r < 0)
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return log_warning_errno(r, "Failed to parse DNSKEY key data %s on line %s:%u", key, path, line);
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rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_DNSKEY, domain);
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if (!rr)
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return log_oom();
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rr->dnskey.flags = f;
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rr->dnskey.protocol = 3;
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rr->dnskey.algorithm = a;
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rr->dnskey.key_size = l;
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rr->dnskey.key = k;
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k = NULL;
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} else {
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log_warning("RR type %s is not supported, ignoring line %s:%u.", type, path, line);
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return -EINVAL;
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}
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if (!isempty(p)) {
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log_warning("Trailing garbage on line %s:%u, ignoring line.", path, line);
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return -EINVAL;
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}
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r = hashmap_ensure_allocated(&d->positive_by_key, &dns_resource_key_hash_ops);
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if (r < 0)
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return r;
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old_answer = hashmap_get(d->positive_by_key, rr->key);
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answer = dns_answer_ref(old_answer);
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r = dns_answer_add_extend(&answer, rr, 0, DNS_ANSWER_AUTHENTICATED);
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if (r < 0)
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return log_error_errno(r, "Failed to add trust anchor RR: %m");
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r = hashmap_replace(d->positive_by_key, rr->key, answer);
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if (r < 0)
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return log_error_errno(r, "Failed to add answer to trust anchor: %m");
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old_answer = dns_answer_unref(old_answer);
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answer = NULL;
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return 0;
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}
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static int dns_trust_anchor_load_negative(DnsTrustAnchor *d, const char *path, unsigned line, const char *s) {
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_cleanup_free_ char *domain = NULL;
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const char *p = s;
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int r;
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assert(d);
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assert(line);
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r = extract_first_word(&p, &domain, NULL, EXTRACT_QUOTES);
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if (r < 0)
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return log_warning_errno(r, "Unable to parse line %s:%u: %m", path, line);
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if (!dns_name_is_valid(domain)) {
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log_warning("Domain name %s is invalid, at line %s:%u, ignoring line.", domain, path, line);
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return -EINVAL;
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}
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if (!isempty(p)) {
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log_warning("Trailing garbage at line %s:%u, ignoring line.", path, line);
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return -EINVAL;
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}
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r = set_ensure_allocated(&d->negative_by_name, &dns_name_hash_ops);
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if (r < 0)
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return r;
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r = set_put(d->negative_by_name, domain);
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if (r < 0)
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return log_oom();
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if (r > 0)
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domain = NULL;
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return 0;
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}
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static int dns_trust_anchor_load_files(
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DnsTrustAnchor *d,
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const char *suffix,
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int (*loader)(DnsTrustAnchor *d, const char *path, unsigned n, const char *line)) {
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_cleanup_strv_free_ char **files = NULL;
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char **f;
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int r;
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assert(d);
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assert(suffix);
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assert(loader);
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r = conf_files_list_nulstr(&files, suffix, NULL, trust_anchor_dirs);
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if (r < 0)
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return log_error_errno(r, "Failed to enumerate %s trust anchor files: %m", suffix);
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STRV_FOREACH(f, files) {
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_cleanup_fclose_ FILE *g = NULL;
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char line[LINE_MAX];
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unsigned n = 0;
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g = fopen(*f, "r");
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if (!g) {
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if (errno == ENOENT)
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continue;
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log_warning_errno(errno, "Failed to open %s: %m", *f);
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continue;
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}
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FOREACH_LINE(line, g, log_warning_errno(errno, "Failed to read %s, ignoring: %m", *f)) {
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char *l;
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n++;
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l = strstrip(line);
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if (isempty(l))
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continue;
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if (*l == ';')
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continue;
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(void) loader(d, *f, n, l);
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}
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}
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return 0;
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}
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static void dns_trust_anchor_dump(DnsTrustAnchor *d) {
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DnsAnswer *a;
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Iterator i;
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assert(d);
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log_info("Positive Trust Anchors:");
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HASHMAP_FOREACH(a, d->positive_by_key, i) {
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DnsResourceRecord *rr;
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DNS_ANSWER_FOREACH(rr, a)
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log_info("%s", dns_resource_record_to_string(rr));
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}
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if (!set_isempty(d->negative_by_name)) {
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char *n;
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log_info("Negative trust anchors:");
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SET_FOREACH(n, d->negative_by_name, i)
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log_info("%s%s", n, endswith(n, ".") ? "" : ".");
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}
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}
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int dns_trust_anchor_load(DnsTrustAnchor *d) {
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int r;
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assert(d);
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/* If loading things from disk fails, we don't consider this fatal */
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(void) dns_trust_anchor_load_files(d, ".positive", dns_trust_anchor_load_positive);
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(void) dns_trust_anchor_load_files(d, ".negative", dns_trust_anchor_load_negative);
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/* However, if the built-in DS fails, then we have a problem. */
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r = dns_trust_anchor_add_builtin(d);
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if (r < 0)
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return log_error_errno(r, "Failed to add trust anchor built-in: %m");
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dns_trust_anchor_dump(d);
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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->positive_by_key)))
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dns_answer_unref(a);
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d->positive_by_key = hashmap_free(d->positive_by_key);
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d->negative_by_name = set_free_free(d->negative_by_name);
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}
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int dns_trust_anchor_lookup_positive(DnsTrustAnchor *d, const 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->positive_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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int dns_trust_anchor_lookup_negative(DnsTrustAnchor *d, const char *name) {
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assert(d);
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assert(name);
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return set_contains(d->negative_by_name, name);
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}
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