upstream: test that UserKnownHostsFile correctly accepts multiple

arguments; would have caught readconf.c r1.356 regression

OpenBSD-Regress-ID: 71ca54e66c2a0211b04999263e56390b1f323a6a

regress/cert-hostkey.sh

@@ -1,4 +1,4 @@
-#	$OpenBSD: cert-hostkey.sh,v 1.24 2021/02/25 03:27:34 djm Exp $
+#	$OpenBSD: cert-hostkey.sh,v 1.25 2021/06/08 22:30:27 djm Exp $
 #	Placed in the Public Domain.
 
 tid="certified host keys"
@@ -283,11 +283,17 @@ for ktype in $PLAIN_TYPES ; do
 	) > $OBJ/sshd_proxy
 
 	${SSH} -oUserKnownHostsFile=$OBJ/known_hosts-cert \
-	    -oGlobalKnownHostsFile=$OBJ/known_hosts-cert \
-		-F $OBJ/ssh_proxy somehost true
+	    -oGlobalKnownHostsFile=none -F $OBJ/ssh_proxy somehost true
 	if [ $? -ne 0 ]; then
 		fail "ssh cert connect failed"
 	fi
+	# Also check that it works when the known_hosts file is not in the
+	# first array position.
+	${SSH} -oUserKnownHostsFile="/dev/null $OBJ/known_hosts-cert" \
+	    -oGlobalKnownHostsFile=none -F $OBJ/ssh_proxy somehost true
+	if [ $? -ne 0 ]; then
+		fail "ssh cert connect failed known_hosts 2nd"
+	fi
 done
 
 # Wrong certificate