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-rw-r--r--src/resolve/resolved-dns-answer.c21
-rw-r--r--src/resolve/resolved-dns-answer.h1
-rw-r--r--src/resolve/resolved-dns-cache.c25
3 files changed, 40 insertions, 7 deletions
diff --git a/src/resolve/resolved-dns-answer.c b/src/resolve/resolved-dns-answer.c
index 13ad4ca6bd..89b9b0e1ea 100644
--- a/src/resolve/resolved-dns-answer.c
+++ b/src/resolve/resolved-dns-answer.c
@@ -149,6 +149,19 @@ int dns_answer_contains(DnsAnswer *a, DnsResourceKey *key) {
return 0;
}
+int dns_answer_match_soa(DnsResourceKey *key, DnsResourceKey *soa) {
+ if (soa->class != DNS_CLASS_IN)
+ return 0;
+
+ if (soa->type != DNS_TYPE_SOA)
+ return 0;
+
+ if (!dns_name_endswith(DNS_RESOURCE_KEY_NAME(key), DNS_RESOURCE_KEY_NAME(soa)))
+ return 0;
+
+ return 1;
+}
+
int dns_answer_find_soa(DnsAnswer *a, DnsResourceKey *key, DnsResourceRecord **ret) {
unsigned i;
@@ -164,13 +177,7 @@ int dns_answer_find_soa(DnsAnswer *a, DnsResourceKey *key, DnsResourceRecord **r
for (i = 0; i < a->n_rrs; i++) {
- if (a->items[i].rr->key->class != DNS_CLASS_IN)
- continue;
-
- if (a->items[i].rr->key->type != DNS_TYPE_SOA)
- continue;
-
- if (dns_name_endswith(DNS_RESOURCE_KEY_NAME(key), DNS_RESOURCE_KEY_NAME(a->items[i].rr->key))) {
+ if (dns_answer_match_soa(key, a->items[i].rr->key)) {
*ret = a->items[i].rr;
return 1;
}
diff --git a/src/resolve/resolved-dns-answer.h b/src/resolve/resolved-dns-answer.h
index 0757dd60d0..044d73b19c 100644
--- a/src/resolve/resolved-dns-answer.h
+++ b/src/resolve/resolved-dns-answer.h
@@ -49,6 +49,7 @@ DnsAnswer *dns_answer_unref(DnsAnswer *a);
int dns_answer_add(DnsAnswer *a, DnsResourceRecord *rr, int ifindex);
int dns_answer_add_soa(DnsAnswer *a, const char *name, uint32_t ttl);
int dns_answer_contains(DnsAnswer *a, DnsResourceKey *key);
+int dns_answer_match_soa(DnsResourceKey *key, DnsResourceKey *soa);
int dns_answer_find_soa(DnsAnswer *a, DnsResourceKey *key, DnsResourceRecord **ret);
DnsAnswer *dns_answer_merge(DnsAnswer *a, DnsAnswer *b);
diff --git a/src/resolve/resolved-dns-cache.c b/src/resolve/resolved-dns-cache.c
index 93b98f3727..ab13636bc1 100644
--- a/src/resolve/resolved-dns-cache.c
+++ b/src/resolve/resolved-dns-cache.c
@@ -474,6 +474,31 @@ int dns_cache_put(
if (r == 0)
return 0;
+ /* Also, if the requested key is an alias, the negative response should
+ be cached for each name in the redirect chain. Any CNAME record in
+ the response is from the redirection chain, though only the final one
+ is guaranteed to be included. This means that we cannot verify the
+ chain and that we need to cache them all as it may be incomplete. */
+ for (i = 0; i < answer->n_rrs; i++) {
+ DnsResourceRecord *answer_rr = answer->items[i].rr;
+
+ if (answer_rr->key->type == DNS_TYPE_CNAME) {
+ _cleanup_(dns_resource_key_unrefp) DnsResourceKey *canonical_key = NULL;
+
+ canonical_key = dns_resource_key_new_redirect(key, answer_rr);
+ if (!canonical_key)
+ goto fail;
+
+ /* Let's not add negative cache entries for records outside the current zone. */
+ if (!dns_answer_match_soa(canonical_key, soa->key))
+ continue;
+
+ r = dns_cache_put_negative(c, canonical_key, rcode, timestamp, MIN(soa->soa.minimum, soa->ttl), owner_family, owner_address);
+ if (r < 0)
+ goto fail;
+ }
+ }
+
r = dns_cache_put_negative(c, key, rcode, timestamp, MIN(soa->soa.minimum, soa->ttl), owner_family, owner_address);
if (r < 0)
goto fail;