diff --git a/src/libsystemd/sd-bus/bus-creds.c b/src/libsystemd/sd-bus/bus-creds.c
index b180a03..6896bcf 100644
--- a/src/libsystemd/sd-bus/bus-creds.c
+++ b/src/libsystemd/sd-bus/bus-creds.c
@@ -651,7 +651,7 @@ _public_ int sd_bus_creds_get_description(sd_bus_creds *c, const char **ret) {
         return 0;
 }
 
-static int has_cap(sd_bus_creds *c, unsigned offset, int capability) {
+static int has_cap(sd_bus_creds *c, size_t offset, int capability) {
         size_t sz;
 
         assert(c);