bus-error: verify additional error maps during installation

Go over the entries in the map and check that they make sense.
Tests are added. In the future we might want to do additional
checks, e.g. verifying that the error names are in the expected
format.

1 files changed, 10 insertions, 8 deletions

diff --git a/src/libsystemd/sd-bus/bus-error.c b/src/libsystemd/sd-bus/bus-error.c
index a99d55c47a..c77eb5fd03 100644
--- a/src/libsystemd/sd-bus/bus-error.c
+++ b/src/libsystemd/sd-bus/bus-error.c
@@ -579,27 +579,29 @@ const char *bus_error_message(const sd_bus_error *e, int error) {
         return strerror(error);
 }
 
+static bool map_ok(const sd_bus_error_map *map) {
+        for (; map->code != BUS_ERROR_MAP_END_MARKER; map++)
+                if (!map->name || map->code <=0)
+                        return false;
+        return true;
+}
+
 _public_ int sd_bus_error_add_map(const sd_bus_error_map *map) {
         const sd_bus_error_map **maps = NULL;
         unsigned n = 0;
 
         assert_return(map, -EINVAL);
+        assert_return(map_ok(map), -EINVAL);
 
-        if (additional_error_maps) {
-                for (;; n++) {
-                        if (additional_error_maps[n] == NULL)
-                                break;
-
+        if (additional_error_maps)
+                for (; additional_error_maps[n] != NULL; n++)
                         if (additional_error_maps[n] == map)
                                 return 0;
-                }
-        }
 
         maps = realloc_multiply(additional_error_maps, sizeof(struct sd_bus_error_map*), n + 2);
         if (!maps)
                 return -ENOMEM;
 
-
         maps[n] = map;
         maps[n+1] = NULL;