diff --git a/src/libsystemd/sd-bus/bus-control.c b/src/libsystemd/sd-bus/bus-control.c
index 9cd5cd5fb6d..758715d74e3 100644
--- a/src/libsystemd/sd-bus/bus-control.c
+++ b/src/libsystemd/sd-bus/bus-control.c
@@ -402,6 +402,10 @@ static int bus_populate_creds_from_items(
         uint64_t m;
         int r;
 
+        assert(bus);
+        assert(info);
+        assert(c);
+
         KDBUS_ITEM_FOREACH(item, info, items) {
 
                 switch (item->type) {
@@ -590,18 +594,18 @@ static int bus_populate_creds_from_items(
 
                 case KDBUS_ITEM_AUXGROUPS:
                         if (mask & SD_BUS_CREDS_SUPPLEMENTARY_GIDS) {
-                                size_t i, n;
-                                uid_t *u;
+                                size_t n;
+                                uid_t *g;
 
-                                n = (item->size - offsetof(struct kdbus_item, data64)) / sizeof(uint64_t);
-                                u = new(uid_t, n);
-                                if (!u)
+                                assert_cc(sizeof(gid_t) == sizeof(uint32_t));
+
+                                n = (item->size - offsetof(struct kdbus_item, data32)) / sizeof(uint32_t);
+                                g = newdup(gid_t, item->data32, n);
+                                if (!g)
                                         return -ENOMEM;
 
-                                for (i = 0; i < n; i++)
-                                        u[i] = (uid_t) item->data64[i];
-
-                                c->supplementary_gids = u;
+                                free(c->supplementary_gids);
+                                c->supplementary_gids = g;
                                 c->n_supplementary_gids = n;
 
                                 c->mask |= SD_BUS_CREDS_SUPPLEMENTARY_GIDS;
diff --git a/src/libsystemd/sd-bus/bus-creds.c b/src/libsystemd/sd-bus/bus-creds.c
index 43315b5b502..8aa53362fba 100644
--- a/src/libsystemd/sd-bus/bus-creds.c
+++ b/src/libsystemd/sd-bus/bus-creds.c
@@ -53,8 +53,6 @@ void bus_creds_done(sd_bus_creds *c) {
 
         strv_free(c->cmdline_array);
         strv_free(c->well_known_names);
-
-        free(c->supplementary_gids);
 }
 
 _public_ sd_bus_creds *sd_bus_creds_ref(sd_bus_creds *c) {
@@ -97,6 +95,7 @@ _public_ sd_bus_creds *sd_bus_creds_unref(sd_bus_creds *c) {
                         free(c->unique_name);
                         free(c->cgroup_root);
                         free(c->description);
+                        free(c->supplementary_gids);
                         free(c);
                 }
         } else {
diff --git a/src/libsystemd/sd-bus/bus-kernel.c b/src/libsystemd/sd-bus/bus-kernel.c
index 907c5c5cf64..2beaa892bca 100644
--- a/src/libsystemd/sd-bus/bus-kernel.c
+++ b/src/libsystemd/sd-bus/bus-kernel.c
@@ -677,21 +677,10 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k) {
                 case KDBUS_ITEM_AUXGROUPS:
 
                         if (bus->creds_mask & SD_BUS_CREDS_SUPPLEMENTARY_GIDS) {
-                                size_t i, n;
-                                uid_t *u;
-                                n = (d->size - offsetof(struct kdbus_item, data32)) / sizeof(uint32_t);
-                                u = new(uid_t, n);
-                                if (!u) {
-                                        r = -ENOMEM;
-                                        goto fail;
-                                }
-
-                                for (i = 0; i < n; i++)
-                                        u[i] = (uid_t) d->data32[i];
-
-                                m->creds.supplementary_gids = u;
-                                m->creds.n_supplementary_gids = n;
+                                assert_cc(sizeof(gid_t) == sizeof(uint32_t));
 
+                                m->creds.n_supplementary_gids = (d->size - offsetof(struct kdbus_item, data32)) / sizeof(uint32_t);
+                                m->creds.supplementary_gids = (gid_t*) d->data32;
                                 m->creds.mask |= SD_BUS_CREDS_SUPPLEMENTARY_GIDS;
                         }