From 38866cb5c444d99596f487e459e1cf2ed26ec0d8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ond=C5=99ej=20Sur=C3=BD?= <ondrej@sury.org>
Date: Sun, 13 Oct 2019 06:53:06 +0200
Subject: [PATCH] dnssec: don't qsort() empty hashlist

(cherry picked from commit 6bbb0b8e42cd7b2d6ffd9de8517f1a85e60c8019)
---
 bin/dnssec/dnssec-signzone.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/bin/dnssec/dnssec-signzone.c b/bin/dnssec/dnssec-signzone.c
index 88b910227d..cce743913d 100644
--- a/bin/dnssec/dnssec-signzone.c
+++ b/bin/dnssec/dnssec-signzone.c
@@ -794,7 +794,10 @@ hashlist_comp(const void *a, const void *b) {
 
 static void
 hashlist_sort(hashlist_t *l) {
-	qsort(l->hashbuf, l->entries, l->length, hashlist_comp);
+	INSIST(l->hashbuf != NULL || l->length == 0);
+	if (l->length > 0) {
+		qsort(l->hashbuf, l->entries, l->length, hashlist_comp);
+	}
 }
 
 static bool