resolved: make sure to normalize all domain names returned via the bus

Most domain names we deal with are normalized anyway (since we read them that
way from DNS packets), but some might not (because they are synthesized from
unnormalized configuration or so), hence make sure to normalize all names
before passing them out to clients, to be fully deterministic.

Note that internally we are process normalized and non-normalized names the
same way, and while comparing them ignore the differences due to unnormalized
names. However, that internal implementation detail really shouldn't spill out
the clients, hence make sure to clean it all up.

1 files changed, 30 insertions, 4 deletions

diff --git a/src/resolve/resolved-bus.c b/src/resolve/resolved-bus.c
index 6f08c43327..2d94baeb7e 100644
--- a/src/resolve/resolved-bus.c
+++ b/src/resolve/resolved-bus.c
@@ -140,6 +140,7 @@ static int append_address(sd_bus_message *reply, DnsResourceRecord *rr, int ifin
 static void bus_method_resolve_hostname_complete(DnsQuery *q) {
         _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *canonical = NULL;
         _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
+        _cleanup_free_ char *normalized = NULL;
         DnsResourceRecord *rr;
         unsigned added = 0;
         int ifindex, r;
@@ -199,11 +200,17 @@ static void bus_method_resolve_hostname_complete(DnsQuery *q) {
         if (r < 0)
                 goto finish;
 
+        /* The key names are not necessarily normalized, make sure that they are when we return them to our bus
+         * clients. */
+        r = dns_name_normalize(DNS_RESOURCE_KEY_NAME(canonical->key), &normalized);
+        if (r < 0)
+                goto finish;
+
         /* Return the precise spelling and uppercasing and CNAME target reported by the server */
         assert(canonical);
         r = sd_bus_message_append(
                         reply, "st",
-                        DNS_RESOURCE_KEY_NAME(canonical->key),
+                        normalized,
                         SD_RESOLVED_FLAGS_MAKE(q->answer_protocol, q->answer_family, q->answer_authenticated));
         if (r < 0)
                 goto finish;
@@ -395,13 +402,19 @@ static void bus_method_resolve_address_complete(DnsQuery *q) {
         question = dns_query_question_for_protocol(q, q->answer_protocol);
 
         DNS_ANSWER_FOREACH_IFINDEX(rr, ifindex, q->answer) {
+                _cleanup_free_ char *normalized = NULL;
+
                 r = dns_question_matches_rr(question, rr, NULL);
                 if (r < 0)
                         goto finish;
                 if (r == 0)
                         continue;
 
-                r = sd_bus_message_append(reply, "(is)", ifindex, rr->ptr.name);
+                r = dns_name_normalize(rr->ptr.name, &normalized);
+                if (r < 0)
+                        goto finish;
+
+                r = sd_bus_message_append(reply, "(is)", ifindex, normalized);
                 if (r < 0)
                         goto finish;
 
@@ -671,6 +684,7 @@ fail:
 
 static int append_srv(DnsQuery *q, sd_bus_message *reply, DnsResourceRecord *rr) {
         _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *canonical = NULL;
+        _cleanup_free_ char *normalized = NULL;
         DnsQuery *aux;
         int r;
 
@@ -727,10 +741,14 @@ static int append_srv(DnsQuery *q, sd_bus_message *reply, DnsResourceRecord *rr)
         if (r < 0)
                 return r;
 
+        r = dns_name_normalize(rr->srv.name, &normalized);
+        if (r < 0)
+                return r;
+
         r = sd_bus_message_append(
                         reply,
                         "qqqs",
-                        rr->srv.priority, rr->srv.weight, rr->srv.port, rr->srv.name);
+                        rr->srv.priority, rr->srv.weight, rr->srv.port, normalized);
         if (r < 0)
                 return r;
 
@@ -776,9 +794,17 @@ static int append_srv(DnsQuery *q, sd_bus_message *reply, DnsResourceRecord *rr)
         if (r < 0)
                 return r;
 
+        if (canonical) {
+                normalized = mfree(normalized);
+
+                r = dns_name_normalize(DNS_RESOURCE_KEY_NAME(canonical->key), &normalized);
+                if (r < 0)
+                        return r;
+        }
+
         /* Note that above we appended the hostname as encoded in the
          * SRV, and here the canonical hostname this maps to. */
-        r = sd_bus_message_append(reply, "s", canonical ? DNS_RESOURCE_KEY_NAME(canonical->key) : rr->srv.name);
+        r = sd_bus_message_append(reply, "s", normalized);
         if (r < 0)
                 return r;