return 0;
}
-int dnssec_nsec_test_between(DnsAnswer *answer, const char *name, const char *zone, bool *authenticated) {
+int dnssec_nsec_test_enclosed(DnsAnswer *answer, uint16_t type, const char *name, const char *zone, bool *authenticated) {
DnsResourceRecord *rr;
DnsAnswerFlags flags;
int r;
DNS_ANSWER_FOREACH_FLAGS(rr, flags, answer) {
bool found = false;
+ if (rr->key->type != type && type != DNS_TYPE_ANY)
+ continue;
+
r = dns_name_endswith(DNS_RESOURCE_KEY_NAME(rr->key), zone);
if (r < 0)
return r;
return 0;
}
+static int dnssec_test_positive_wildcard_nsec3(
+ DnsAnswer *answer,
+ const char *name,
+ const char *source,
+ const char *zone,
+ bool *authenticated) {
+
+ const char *next_closer = NULL;
+ int r;
+
+ /* Run a positive NSEC3 wildcard proof. Specifically:
+ *
+ * A proof that the the "next closer" of the generating wildcard does not exist.
+ *
+ * Note a key difference between the NSEC3 and NSEC versions of the proof. NSEC RRs don't have to exist for
+ * empty non-transients. NSEC3 RRs however have to. This means it's sufficient to check if the next closer name
+ * exists for the NSEC3 RR and we are done.
+ *
+ * To prove that a.b.c.d.e.f is rightfully synthesized from a wildcard *.d.e.f all we have to check is that
+ * c.d.e.f does not exist. */
+
+ for (;;) {
+ next_closer = name;
+ r = dns_name_parent(&name);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ return 0;
+
+ r = dns_name_equal(name, source);
+ if (r < 0)
+ return r;
+ if (r > 0)
+ break;
+ }
+
+ return dnssec_nsec_test_enclosed(answer, DNS_TYPE_NSEC3, next_closer, zone, authenticated);
+}
+
+static int dnssec_test_positive_wildcard_nsec(
+ DnsAnswer *answer,
+ const char *name,
+ const char *source,
+ const char *zone,
+ bool *_authenticated) {
+
+ bool authenticated = true;
+ int r;
+
+ /* Run a positive NSEC wildcard proof. Specifically:
+ *
+ * A proof that there's neither a wildcard name nor a non-wildcard name that is a suffix of the name "name" and
+ * a prefix of the synthesizing source "source" in the zone "zone".
+ *
+ * See RFC 5155, Section 8.8 and RFC 4035, Section 5.3.4
+ *
+ * Note that if we want to prove that a.b.c.d.e.f is rightfully synthesized from a wildcard *.d.e.f, then we
+ * have to prove that none of the following exist:
+ *
+ * 1) a.b.c.d.e.f
+ * 2) *.b.c.d.e.f
+ * 3) b.c.d.e.f
+ * 4) *.c.d.e.f
+ * 5) c.d.e.f
+ *
+ */
+
+ for (;;) {
+ _cleanup_free_ char *wc = NULL;
+ bool a = false;
+
+ /* Check if there's an NSEC or NSEC3 RR that proves that the mame we determined is really non-existing,
+ * i.e between the owner name and the next name of an NSEC RR. */
+ r = dnssec_nsec_test_enclosed(answer, DNS_TYPE_NSEC, name, zone, &a);
+ if (r <= 0)
+ return r;
+
+ authenticated = authenticated && a;
+
+ /* Strip one label off */
+ r = dns_name_parent(&name);
+ if (r <= 0)
+ return r;
+
+ /* Did we reach the source of synthesis? */
+ r = dns_name_equal(name, source);
+ if (r < 0)
+ return r;
+ if (r > 0) {
+ /* Successful exit */
+ *_authenticated = authenticated;
+ return 1;
+ }
+
+ /* Safety check, that the source of synthesis is still our suffix */
+ r = dns_name_endswith(name, source);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ return -EBADMSG;
+
+ /* Replace the label we stripped off with an asterisk */
+ wc = strappend("*.", name);
+ if (!wc)
+ return -ENOMEM;
+
+ /* And check if the proof holds for the asterisk name, too */
+ r = dnssec_nsec_test_enclosed(answer, DNS_TYPE_NSEC, wc, zone, &a);
+ if (r <= 0)
+ return r;
+
+ authenticated = authenticated && a;
+ /* In the next iteration we'll check the non-asterisk-prefixed version */
+ }
+}
+
+int dnssec_test_positive_wildcard(
+ DnsAnswer *answer,
+ const char *name,
+ const char *source,
+ const char *zone,
+ bool *authenticated) {
+
+ int r;
+
+ assert(name);
+ assert(source);
+ assert(zone);
+ assert(authenticated);
+
+ r = dns_answer_contains_zone_nsec3(answer, zone);
+ if (r < 0)
+ return r;
+ if (r > 0)
+ return dnssec_test_positive_wildcard_nsec3(answer, name, source, zone, authenticated);
+ else
+ return dnssec_test_positive_wildcard_nsec(answer, name, source, zone, authenticated);
+}
+
static const char* const dnssec_result_table[_DNSSEC_RESULT_MAX] = {
[DNSSEC_VALIDATED] = "validated",
[DNSSEC_VALIDATED_WILDCARD] = "validated-wildcard",
if (result == DNSSEC_VALIDATED_WILDCARD) {
bool authenticated = false;
- const char *suffix;
+ const char *source;
- /* This RRset validated, but as a wildcard. This means we need to proof via NSEC/NSEC3
- * that no matching non-wildcard RR exists.
- *
- * See RFC 5155, Section 8.8 and RFC 4035, Section 5.3.4*/
+ /* This RRset validated, but as a wildcard. This means we need to prove via NSEC/NSEC3
+ * that no matching non-wildcard RR exists.*/
- r = dns_name_suffix(DNS_RESOURCE_KEY_NAME(rr->key), rrsig->rrsig.labels, &suffix);
+ /* First step, determine the source of synthesis */
+ r = dns_name_suffix(DNS_RESOURCE_KEY_NAME(rr->key), rrsig->rrsig.labels, &source);
if (r < 0)
return r;
if (r == 0)
return -EBADMSG;
- r = dns_name_parent(&suffix);
- if (r < 0)
- return r;
- if (r == 0)
- return -EBADMSG;
-
- r = dnssec_nsec_test_between(validated, DNS_RESOURCE_KEY_NAME(rr->key), suffix, &authenticated);
- if (r < 0)
- return r;
+ r = dnssec_test_positive_wildcard(
+ validated,
+ DNS_RESOURCE_KEY_NAME(rr->key),
+ source,
+ rrsig->rrsig.signer,
+ &authenticated);
/* Unless the NSEC proof showed that the key really doesn't exist something is off. */
if (r == 0)
projects / platform / upstream / systemd.git / commitdiff