From de1f3564cd85915b3002859873a37cb8d31ac9ce Mon Sep 17 00:00:00 2001
From: "dtucker@openbsd.org" <dtucker@openbsd.org>
Date: Tue, 18 Feb 2020 08:49:49 +0000
Subject: [PATCH] upstream: Detect and prevent simple configuration loops when
 using

ProxyJump. bz#3057, ok djm@

OpenBSD-Commit-ID: 077d21c564c886c98309d871ed6f8ef267b9f037
---
 ssh.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/ssh.c b/ssh.c
index 15aee569e..a983a108b 100644
--- a/ssh.c
+++ b/ssh.c
@@ -1208,6 +1208,14 @@ main(int ac, char **av)
 	if (options.jump_host != NULL) {
 		char port_s[8];
 		const char *sshbin = argv0;
+		int port = options.port, jumpport = options.jump_port;
+
+		if (port <= 0)
+			port = default_ssh_port();
+		if (jumpport <= 0)
+			jumpport = default_ssh_port();
+		if (strcmp(options.jump_host, host) == 0 && port == jumpport)
+			fatal("jumphost loop via %s", options.jump_host);
 
 		/*
 		 * Try to use SSH indicated by argv[0], but fall back to