ensure we have a zone origin (#1105)

diff --git a/dns/dnssec.py b/dns/dnssec.py
index e49c3b795b5108486700e79e6c4ea7c534adcebf..6a7b78eabd0d6b0bc04a8731213dad9f1ed4540a 100644 (file)
--- a/dns/dnssec.py
+++ b/dns/dnssec.py
@@ -1056,6 +1056,9 @@ def sign_zone(
     else:
         cm = zone.writer()
 
+    if zone.origin is None:
+        raise ValueError("no zone origin")
+
     with cm as _txn:
         if add_dnskey:
             if dnskey_ttl is None: