sd-bus: properly match ID changes

If the caller does not specify arg1 for NameOwnerChanged matches, we
really must take the ID from arg2 or arg3, if provided. They are
guaranteed to be identical to arg1 if either is supplied, but there is no
strict requiredment that arg1 is supplied. Hence, make sure to always
take the more restrictive match. Otherwise, we install rather wide
matches without anyone requiring them.

diff --git a/src/libelogind/sd-bus/bus-control.c b/src/libelogind/sd-bus/bus-control.c
index 526e1aa89ff750c5becd6095321cd013d3a7dacc..99115d5e492f4157ee3722bc51a4e60131d63b8a 100644 (file)
--- a/src/libelogind/sd-bus/bus-control.c
+++ b/src/libelogind/sd-bus/bus-control.c
@@ -1187,6 +1187,8 @@ static int add_name_change_match(sd_bus *bus,
                  * match against added ids */
                 if (!old_owner || old_owner[0] == 0) {
                         item->type = KDBUS_ITEM_ID_ADD;
+                        if (!isempty(new_owner))
+                                item->id_change.id = new_owner_id;
 
                         r = ioctl(bus->input_fd, KDBUS_CMD_MATCH_ADD, m);
                         if (r < 0)
@@ -1197,6 +1199,8 @@ static int add_name_change_match(sd_bus *bus,
                  * match against removed ids */
                 if (!new_owner || new_owner[0] == 0) {
                         item->type = KDBUS_ITEM_ID_REMOVE;
+                        if (!isempty(old_owner))
+                                item->id_change.id = old_owner_id;
 
                         r = ioctl(bus->input_fd, KDBUS_CMD_MATCH_ADD, m);
                         if (r < 0)