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Diffstat (limited to 'src/resolve/resolved-dns-trust-anchor.c')
-rw-r--r--src/resolve/resolved-dns-trust-anchor.c180
1 files changed, 148 insertions, 32 deletions
diff --git a/src/resolve/resolved-dns-trust-anchor.c b/src/resolve/resolved-dns-trust-anchor.c
index 53b49b091a..9f8b76ebe2 100644
--- a/src/resolve/resolved-dns-trust-anchor.c
+++ b/src/resolve/resolved-dns-trust-anchor.c
@@ -42,7 +42,18 @@ static const uint8_t root_digest[] =
{ 0x49, 0xAA, 0xC1, 0x1D, 0x7B, 0x6F, 0x64, 0x46, 0x70, 0x2E, 0x54, 0xA1, 0x60, 0x73, 0x71, 0x60,
0x7A, 0x1A, 0x41, 0x85, 0x52, 0x00, 0xFD, 0x2C, 0xE1, 0xCD, 0xDE, 0x32, 0xF2, 0x4E, 0x8F, 0xB5 };
-static int dns_trust_anchor_add_builtin(DnsTrustAnchor *d) {
+static bool dns_trust_anchor_knows_domain_positive(DnsTrustAnchor *d, const char *name) {
+ assert(d);
+
+ /* Returns true if there's an entry for the specified domain
+ * name in our trust anchor */
+
+ return
+ hashmap_contains(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN, DNS_TYPE_DNSKEY, name)) ||
+ hashmap_contains(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN, DNS_TYPE_DS, name));
+}
+
+static int dns_trust_anchor_add_builtin_positive(DnsTrustAnchor *d) {
_cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
_cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
int r;
@@ -53,10 +64,11 @@ static int dns_trust_anchor_add_builtin(DnsTrustAnchor *d) {
if (r < 0)
return r;
- if (hashmap_get(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN, DNS_TYPE_DS, ".")))
- return 0;
-
- if (hashmap_get(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN, DNS_TYPE_DNSKEY, ".")))
+ /* Only add the built-in trust anchor if there's neither a DS
+ * nor a DNSKEY defined for the root domain. That way users
+ * have an easy way to override the root domain DS/DNSKEY
+ * data. */
+ if (dns_trust_anchor_knows_domain_positive(d, "."))
return 0;
/* Add the RR from https://data.iana.org/root-anchors/root-anchors.xml */
@@ -88,6 +100,95 @@ static int dns_trust_anchor_add_builtin(DnsTrustAnchor *d) {
return 0;
}
+static int dns_trust_anchor_add_builtin_negative(DnsTrustAnchor *d) {
+
+ static const char private_domains[] =
+ /* RFC 6761 says that .test is a special domain for
+ * testing and not to be installed in the root zone */
+ "test\0"
+
+ /* RFC 6761 says that these reverse IP lookup ranges
+ * are for private addresses, and hence should not
+ * show up in the root zone */
+ "10.in-addr.arpa\0"
+ "16.172.in-addr.arpa\0"
+ "17.172.in-addr.arpa\0"
+ "18.172.in-addr.arpa\0"
+ "19.172.in-addr.arpa\0"
+ "20.172.in-addr.arpa\0"
+ "21.172.in-addr.arpa\0"
+ "22.172.in-addr.arpa\0"
+ "23.172.in-addr.arpa\0"
+ "24.172.in-addr.arpa\0"
+ "25.172.in-addr.arpa\0"
+ "26.172.in-addr.arpa\0"
+ "27.172.in-addr.arpa\0"
+ "28.172.in-addr.arpa\0"
+ "29.172.in-addr.arpa\0"
+ "30.172.in-addr.arpa\0"
+ "31.172.in-addr.arpa\0"
+ "168.192.in-addr.arpa\0"
+
+ /* RFC 6762 reserves the .local domain for Multicast
+ * DNS, it hence cannot appear in the root zone. (Note
+ * that we by default do not route .local traffic to
+ * DNS anyway, except when a configured search domain
+ * suggests so.) */
+ "local\0"
+
+ /* These two are well known, popular private zone
+ * TLDs, that are blocked from delegation, according
+ * to:
+ * http://icannwiki.com/Name_Collision#NGPC_Resolution
+ *
+ * There's also ongoing work on making this official
+ * in an RRC:
+ * https://www.ietf.org/archive/id/draft-chapin-additional-reserved-tlds-02.txt */
+ "home\0"
+ "corp\0"
+
+ /* The following four TLDs are suggested for private
+ * zones in RFC 6762, Appendix G, and are hence very
+ * unlikely to be made official TLDs any day soon */
+ "lan\0"
+ "intranet\0"
+ "internal\0"
+ "private\0";
+
+ const char *name;
+ int r;
+
+ assert(d);
+
+ /* Only add the built-in trust anchor if there's no negative
+ * trust anchor defined at all. This enables easy overriding
+ * of negative trust anchors. */
+
+ if (set_size(d->negative_by_name) > 0)
+ return 0;
+
+ r = set_ensure_allocated(&d->negative_by_name, &dns_name_hash_ops);
+ if (r < 0)
+ return r;
+
+ /* We add a couple of domains as default negative trust
+ * anchors, where it's very unlikely they will be installed in
+ * the root zone. If they exist they must be private, and thus
+ * unsigned. */
+
+ NULSTR_FOREACH(name, private_domains) {
+
+ if (dns_trust_anchor_knows_domain_positive(d, name))
+ continue;
+
+ r = set_put_strdup(d->negative_by_name, name);
+ if (r < 0)
+ return r;
+ }
+
+ return 0;
+}
+
static int dns_trust_anchor_load_positive(DnsTrustAnchor *d, const char *path, unsigned line, const char *s) {
_cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
_cleanup_free_ char *domain = NULL, *class = NULL, *type = NULL;
@@ -236,7 +337,7 @@ static int dns_trust_anchor_load_positive(DnsTrustAnchor *d, const char *path, u
r = hashmap_ensure_allocated(&d->positive_by_key, &dns_resource_key_hash_ops);
if (r < 0)
- return r;
+ return log_oom();
old_answer = hashmap_get(d->positive_by_key, rr->key);
answer = dns_answer_ref(old_answer);
@@ -279,7 +380,7 @@ static int dns_trust_anchor_load_negative(DnsTrustAnchor *d, const char *path, u
r = set_ensure_allocated(&d->negative_by_name, &dns_name_hash_ops);
if (r < 0)
- return r;
+ return log_oom();
r = set_put(d->negative_by_name, domain);
if (r < 0)
@@ -340,27 +441,49 @@ static int dns_trust_anchor_load_files(
return 0;
}
-static void dns_trust_anchor_dump(DnsTrustAnchor *d) {
+static int domain_name_cmp(const void *a, const void *b) {
+ char **x = (char**) a, **y = (char**) b;
+
+ return dns_name_compare_func(*x, *y);
+}
+
+static int dns_trust_anchor_dump(DnsTrustAnchor *d) {
DnsAnswer *a;
Iterator i;
assert(d);
- log_info("Positive Trust Anchors:");
- HASHMAP_FOREACH(a, d->positive_by_key, i) {
- DnsResourceRecord *rr;
+ if (hashmap_isempty(d->positive_by_key))
+ log_info("No positive trust anchors defined.");
+ else {
+ log_info("Positive Trust Anchors:");
+ HASHMAP_FOREACH(a, d->positive_by_key, i) {
+ DnsResourceRecord *rr;
- DNS_ANSWER_FOREACH(rr, a)
- log_info("%s", dns_resource_record_to_string(rr));
+ DNS_ANSWER_FOREACH(rr, a)
+ log_info("%s", dns_resource_record_to_string(rr));
+ }
}
- if (!set_isempty(d->negative_by_name)) {
- char *n;
- log_info("Negative trust anchors:");
+ if (set_isempty(d->negative_by_name))
+ log_info("No negative trust anchors defined.");
+ else {
+ _cleanup_free_ char **l = NULL, *j = NULL;
+
+ l = set_get_strv(d->negative_by_name);
+ if (!l)
+ return log_oom();
+
+ qsort_safe(l, set_size(d->negative_by_name), sizeof(char*), domain_name_cmp);
+
+ j = strv_join(l, " ");
+ if (!j)
+ return log_oom();
- SET_FOREACH(n, d->negative_by_name, i)
- log_info("%s%s", n, endswith(n, ".") ? "" : ".");
+ log_info("Negative trust anchors: %s", j);
}
+
+ return 0;
}
int dns_trust_anchor_load(DnsTrustAnchor *d) {
@@ -373,9 +496,13 @@ int dns_trust_anchor_load(DnsTrustAnchor *d) {
(void) dns_trust_anchor_load_files(d, ".negative", dns_trust_anchor_load_negative);
/* However, if the built-in DS fails, then we have a problem. */
- r = dns_trust_anchor_add_builtin(d);
+ r = dns_trust_anchor_add_builtin_positive(d);
+ if (r < 0)
+ return log_error_errno(r, "Failed to add built-in positive trust anchor: %m");
+
+ r = dns_trust_anchor_add_builtin_negative(d);
if (r < 0)
- return log_error_errno(r, "Failed to add trust anchor built-in: %m");
+ return log_error_errno(r, "Failed to add built-in negative trust anchor: %m");
dns_trust_anchor_dump(d);
@@ -516,17 +643,6 @@ static int dns_trust_anchor_check_revoked_one(DnsTrustAnchor *d, DnsResourceReco
return 0;
}
-static bool dns_trust_anchor_knows_domain(DnsTrustAnchor *d, const char *name) {
- assert(d);
-
- /* Returns true if there's an entry for the specified domain
- * name in our trust anchor */
-
- return
- hashmap_contains(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN, DNS_TYPE_DNSKEY, name)) ||
- hashmap_contains(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN, DNS_TYPE_DS, name));
-}
-
int dns_trust_anchor_check_revoked(DnsTrustAnchor *d, DnsAnswer *rrs, const DnsResourceKey *key) {
DnsResourceRecord *dnskey;
int r;
@@ -556,7 +672,7 @@ int dns_trust_anchor_check_revoked(DnsTrustAnchor *d, DnsAnswer *rrs, const DnsR
/* Could this be interesting to us at all? If not,
* there's no point in looking for and verifying a
* self-signed RRSIG. */
- if (!dns_trust_anchor_knows_domain(d, DNS_RESOURCE_KEY_NAME(dnskey->key)))
+ if (!dns_trust_anchor_knows_domain_positive(d, DNS_RESOURCE_KEY_NAME(dnskey->key)))
continue;
/* Look for a self-signed RRSIG */
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-09-11 06:39:16 +0000