diff --git a/lib/cache.c b/lib/cache.c
index 5cfae67..45a1a27 100644
--- a/lib/cache.c
+++ b/lib/cache.c
@@ -929,6 +929,9 @@ void nl_cache_dump_filter(struct nl_cache *cache,
 	if (!ops->oo_dump[type])
 		return;
 
+	if (params->dp_buf)
+		memset(params->dp_buf, 0, params->dp_buflen);
+
 	nl_list_for_each_entry(obj, &cache->c_items, ce_list) {
 		if (filter && !nl_object_match_filter(obj, filter))
 			continue;
diff --git a/lib/object.c b/lib/object.c
index 7606535..df1c963 100644
--- a/lib/object.c
+++ b/lib/object.c
@@ -259,6 +259,9 @@ int nl_object_is_marked(struct nl_object *obj)
  */
 void nl_object_dump(struct nl_object *obj, struct nl_dump_params *params)
 {
+	if (params->dp_buf)
+		memset(params->dp_buf, 0, params->dp_buflen);
+
 	dump_from_ops(obj, params);
 }
 
diff --git a/lib/utils.c b/lib/utils.c
index 5a35a53..36b6292 100644
--- a/lib/utils.c
+++ b/lib/utils.c
@@ -824,7 +824,7 @@ void nl_new_line(struct nl_dump_params *params)
 			else if (params->dp_buf)
 				strncat(params->dp_buf, " ",
 					params->dp_buflen -
-					sizeof(params->dp_buf) - 1);
+					strlen(params->dp_buf) - 1);
 		}
 	}
 
@@ -844,7 +844,8 @@ static void dump_one(struct nl_dump_params *parms, const char *fmt,
 				parms->dp_cb(parms, buf);
 			else
 				strncat(parms->dp_buf, buf,
-					parms->dp_buflen - strlen(parms->dp_buf) - 1);
+					parms->dp_buflen -
+					strlen(parms->dp_buf) - 1);
 			free(buf);
 		}
 	}
@@ -1053,9 +1054,6 @@ void dump_from_ops(struct nl_object *obj, struct nl_dump_params *params)
 		params->dp_pre_dump = 1;
 	}
 
-	if (params->dp_buf)
-                memset(params->dp_buf, 0, params->dp_buflen);
-
 	if (obj->ce_ops->oo_dump[type])
 		obj->ce_ops->oo_dump[type](obj, params);
 }