CVE-2021-30218
https://github.com/michaelforney/samurai/commit/e84b6d99c85043fa1ba54851ee500540ec206918

Index: util.c
--- util.c.orig
+++ util.c
@@ -258,7 +258,7 @@ writefile(const char *name, struct string *s)
 		return -1;
 	}
 	ret = 0;
-	if (fwrite(s->s, 1, s->n, f) != s->n || fflush(f) != 0) {
+	if (s && (fwrite(s->s, 1, s->n, f) != s->n || fflush(f) != 0)) {
 		warn("write %s:", name);
 		ret = -1;
 	}