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-rw-r--r--src/resolve/resolved-dns-answer.c27
-rw-r--r--src/resolve/resolved-dns-answer.h1
-rw-r--r--src/resolve/resolved-dns-dnssec.c144
-rw-r--r--src/resolve/resolved-dns-dnssec.h5
-rw-r--r--src/resolve/resolved-dns-transaction.c26
5 files changed, 186 insertions, 17 deletions
diff --git a/src/resolve/resolved-dns-answer.c b/src/resolve/resolved-dns-answer.c
index b50558e280..c359432a7a 100644
--- a/src/resolve/resolved-dns-answer.c
+++ b/src/resolve/resolved-dns-answer.c
@@ -320,6 +320,33 @@ int dns_answer_contains_nsec_or_nsec3(DnsAnswer *a) {
return false;
}
+int dns_answer_contains_zone_nsec3(DnsAnswer *answer, const char *zone) {
+ DnsResourceRecord *rr;
+ int r;
+
+ /* Checks whether the specified answer contains at least one NSEC3 RR in the specified zone */
+
+ DNS_ANSWER_FOREACH(rr, answer) {
+ const char *p;
+
+ if (rr->key->type != DNS_TYPE_NSEC3)
+ continue;
+
+ p = DNS_RESOURCE_KEY_NAME(rr->key);
+ r = dns_name_parent(&p);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ continue;
+
+ r = dns_name_equal(p, zone);
+ if (r != 0)
+ return r;
+ }
+
+ return false;
+}
+
int dns_answer_find_soa(DnsAnswer *a, const DnsResourceKey *key, DnsResourceRecord **ret, DnsAnswerFlags *flags) {
DnsResourceRecord *rr, *soa = NULL;
DnsAnswerFlags rr_flags, soa_flags = 0;
diff --git a/src/resolve/resolved-dns-answer.h b/src/resolve/resolved-dns-answer.h
index 715e487d94..3eff21f8d0 100644
--- a/src/resolve/resolved-dns-answer.h
+++ b/src/resolve/resolved-dns-answer.h
@@ -64,6 +64,7 @@ int dns_answer_match_key(DnsAnswer *a, const DnsResourceKey *key, DnsAnswerFlags
int dns_answer_contains_rr(DnsAnswer *a, DnsResourceRecord *rr, DnsAnswerFlags *combined_flags);
int dns_answer_contains_key(DnsAnswer *a, const DnsResourceKey *key, DnsAnswerFlags *combined_flags);
int dns_answer_contains_nsec_or_nsec3(DnsAnswer *a);
+int dns_answer_contains_zone_nsec3(DnsAnswer *answer, const char *zone);
int dns_answer_find_soa(DnsAnswer *a, const DnsResourceKey *key, DnsResourceRecord **ret, DnsAnswerFlags *flags);
int dns_answer_find_cname_or_dname(DnsAnswer *a, const DnsResourceKey *key, DnsResourceRecord **ret, DnsAnswerFlags *flags);
diff --git a/src/resolve/resolved-dns-dnssec.c b/src/resolve/resolved-dns-dnssec.c
index 6f0f8f837e..afff979b5a 100644
--- a/src/resolve/resolved-dns-dnssec.c
+++ b/src/resolve/resolved-dns-dnssec.c
@@ -1604,7 +1604,7 @@ int dnssec_nsec_test(DnsAnswer *answer, DnsResourceKey *key, DnssecNsecResult *r
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;
@@ -1618,6 +1618,9 @@ int dnssec_nsec_test_between(DnsAnswer *answer, const char *name, const char *zo
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;
@@ -1685,6 +1688,145 @@ int dnssec_nsec_test_between(DnsAnswer *answer, const char *name, const char *zo
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",
diff --git a/src/resolve/resolved-dns-dnssec.h b/src/resolve/resolved-dns-dnssec.h
index 8a9bcf5b91..b9d32db120 100644
--- a/src/resolve/resolved-dns-dnssec.h
+++ b/src/resolve/resolved-dns-dnssec.h
@@ -83,7 +83,10 @@ typedef enum DnssecNsecResult {
} DnssecNsecResult;
int dnssec_nsec_test(DnsAnswer *answer, DnsResourceKey *key, DnssecNsecResult *result, bool *authenticated, uint32_t *ttl);
-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);
+
+int dnssec_test_positive_wildcard(DnsAnswer *a, const char *name, const char *source, const char *zone, bool *authenticated);
const char* dnssec_result_to_string(DnssecResult m) _const_;
DnssecResult dnssec_result_from_string(const char *s) _pure_;
diff --git a/src/resolve/resolved-dns-transaction.c b/src/resolve/resolved-dns-transaction.c
index 9ee10f21c8..c7d2d82ecf 100644
--- a/src/resolve/resolved-dns-transaction.c
+++ b/src/resolve/resolved-dns-transaction.c
@@ -2531,28 +2531,24 @@ int dns_transaction_validate_dnssec(DnsTransaction *t) {
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)
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-12-12 11:48:10 +0000