diff --git a/util.c b/util.c
index 56deaac..cdfbeef 100644
--- a/util.c
+++ b/util.c
@@ -367,7 +367,7 @@ char *x_strndup(const char *s, size_t n)
 
 	if (!s)
 		return NULL;
-	m = strlen(s);
+	m = strnlen(s, n);
 	m = n < m ? n : m;
 	ret = malloc(m + 1);
 	if (ret) {