resolve: check DNSSD service name template before assigning it

src/resolve/resolved-bus.c

@@ -1754,7 +1754,6 @@ static int bus_method_register_service(sd_bus_message *message, void *userdata,
         _cleanup_(dnssd_service_freep) DnssdService *service = NULL;
         _cleanup_(sd_bus_track_unrefp) sd_bus_track *bus_track = NULL;
         _cleanup_free_ char *path = NULL;
-        _cleanup_free_ char *instance_name = NULL;
         Manager *m = userdata;
         DnssdService *s = NULL;
         const char *name;
@@ -1795,6 +1794,10 @@ static int bus_method_register_service(sd_bus_message *message, void *userdata,
         if (!dnssd_srv_type_is_valid(type))
                 return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "DNS-SD service type '%s' is invalid", type);
 
+        r = dnssd_render_instance_name(name_template, NULL);
+        if (r < 0)
+                return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "DNS-SD service name '%s' is invalid", name_template);
+
         service->name = strdup(name);
         if (!service->name)
                 return log_oom();
@@ -1807,10 +1810,6 @@ static int bus_method_register_service(sd_bus_message *message, void *userdata,
         if (!service->type)
                 return log_oom();
 
-        r = dnssd_render_instance_name(service, &instance_name);
-        if (r < 0)
-                return r;
-
         r = sd_bus_message_enter_container(message, SD_BUS_TYPE_ARRAY, "a{say}");
         if (r < 0)
                 return r;

src/resolve/resolved-conf.c

@@ -222,21 +222,19 @@ int config_parse_search_domains(
         return 0;
 }
 
-int config_parse_dnssd_service_name(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata) {
+int config_parse_dnssd_service_name(
-        static const Specifier specifier_table[] = {
+                const char *unit,
-                { 'm', specifier_machine_id,      NULL },
+                const char *filename,
-                { 'b', specifier_boot_id,         NULL },
+                unsigned line,
-                { 'H', specifier_host_name,       NULL },
+                const char *section,
-                { 'v', specifier_kernel_release,  NULL },
+                unsigned section_line,
-                { 'a', specifier_architecture,    NULL },
+                const char *lvalue,
-                { 'o', specifier_os_id,           NULL },
+                int ltype,
-                { 'w', specifier_os_version_id,   NULL },
+                const char *rvalue,
-                { 'B', specifier_os_build_id,     NULL },
+                void *data,
-                { 'W', specifier_os_variant_id,   NULL },
+                void *userdata) {
-                {}
+
-        };
         DnssdService *s = userdata;
-        _cleanup_free_ char *name = NULL;
         int r;
 
         assert(filename);
@@ -245,23 +243,23 @@ int config_parse_dnssd_service_name(const char *unit, const char *filename, unsi
         assert(s);
 
         if (isempty(rvalue)) {
-                log_syntax(unit, LOG_ERR, filename, line, 0, "Service instance name can't be empty. Ignoring.");
+                s->name_template = mfree(s->name_template);
-                return -EINVAL;
+                return 0;
+        }
+
+        r = dnssd_render_instance_name(rvalue, NULL);
+        if (r == -ENOMEM)
+                return log_oom();
+        if (r < 0) {
+                log_syntax(unit, LOG_WARNING, filename, line, r,
+                           "Invalid service instance name template '%s', ignoring: %m", rvalue);
+                return 0;
         }
 
         r = free_and_strdup(&s->name_template, rvalue);
         if (r < 0)
                 return log_oom();
 
-        r = specifier_printf(s->name_template, specifier_table, NULL, &name);
-        if (r < 0)
-                return log_debug_errno(r, "Failed to replace specifiers: %m");
-
-        if (!dns_service_name_is_valid(name)) {
-                log_syntax(unit, LOG_ERR, filename, line, 0, "Service instance name template renders to invalid name '%s'. Ignoring.", name);
-                return -EINVAL;
-        }
-
         return 0;
 }
 

src/resolve/resolved-dnssd.c

@@ -155,7 +155,7 @@ static int specifier_dnssd_host_name(char specifier, const void *data, const voi
         return 0;
 }
 
-int dnssd_render_instance_name(DnssdService *s, char **ret_name) {
+int dnssd_render_instance_name(const char *name_template, char **ret_name) {
         static const Specifier specifier_table[] = {
                 { 'm', specifier_machine_id,      NULL },
                 { 'b', specifier_boot_id,         NULL },
@@ -171,19 +171,17 @@ int dnssd_render_instance_name(DnssdService *s, char **ret_name) {
         _cleanup_free_ char *name = NULL;
         int r;
 
-        assert(s);
+        assert(name_template);
-        assert(s->name_template);
 
-        r = specifier_printf(s->name_template, specifier_table, s, &name);
+        r = specifier_printf(name_template, specifier_table, NULL, &name);
         if (r < 0)
-                return log_debug_errno(r, "Failed to replace specifiers: %m");
+                return r;
 
         if (!dns_service_name_is_valid(name))
-                return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
+                return -EINVAL;
-                                       "Service instance name '%s' is invalid.",
-                                       name);
 
-        *ret_name = TAKE_PTR(name);
+        if (ret_name)
+                *ret_name = TAKE_PTR(name);
 
         return 0;
 }
@@ -227,7 +225,7 @@ int dnssd_update_rrs(DnssdService *s) {
         LIST_FOREACH(items, txt_data, s->txt_data_items)
                 txt_data->rr = dns_resource_record_unref(txt_data->rr);
 
-        r = dnssd_render_instance_name(s, &n);
+        r = dnssd_render_instance_name(s->name_template, &n);
         if (r < 0)
                 return r;
 

src/resolve/resolved-dnssd.h

@@ -51,7 +51,7 @@ DnssdTxtData *dnssd_txtdata_free_all(DnssdTxtData *txt_data);
 DEFINE_TRIVIAL_CLEANUP_FUNC(DnssdService*, dnssd_service_free);
 DEFINE_TRIVIAL_CLEANUP_FUNC(DnssdTxtData*, dnssd_txtdata_free);
 
-int dnssd_render_instance_name(DnssdService *s, char **ret_name);
+int dnssd_render_instance_name(const char *name_template, char **ret_name);
 int dnssd_load(Manager *manager);
 int dnssd_txt_item_new_from_string(const char *key, const char *value, DnsTxtItem **ret_item);
 int dnssd_txt_item_new_from_data(const char *key, const void *value, const size_t size, DnsTxtItem **ret_item);