upstream: make sshd_config:ClientAliveCountMax=0 disable the

connection killing behaviour, rather than killing the connection after
sending the first liveness test probe (regardless of whether the client was
responsive) bz2627; ok markus

OpenBSD-Commit-ID: 5af79c35f4c9fa280643b6852f524bfcd9bccdaf

serverloop.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: serverloop.c,v 1.220 2020/01/25 04:48:26 djm Exp $ */
+/* $OpenBSD: serverloop.c,v 1.221 2020/01/25 22:41:01 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -184,7 +184,8 @@ client_alive_check(struct ssh *ssh)
 	int r, channel_id;
 
 	/* timeout, check to see how many we have had */
-	if (ssh_packet_inc_alive_timeouts(ssh) >
+	if (options.client_alive_count_max > 0 &&
+	    ssh_packet_inc_alive_timeouts(ssh) >
 	    options.client_alive_count_max) {
 		sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id));
 		logit("Timeout, client not responding from %s", remote_id);

sshd_config.5

@@ -33,7 +33,7 @@
 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.\" $OpenBSD: sshd_config.5,v 1.301 2020/01/25 22:36:22 djm Exp $
+.\" $OpenBSD: sshd_config.5,v 1.302 2020/01/25 22:41:01 djm Exp $
 .Dd $Mdocdate: January 25 2020 $
 .Dt SSHD_CONFIG 5
 .Os
@@ -519,6 +519,9 @@ is set to 15, and
 .Cm ClientAliveCountMax
 is left at the default, unresponsive SSH clients
 will be disconnected after approximately 45 seconds.
+Setting a zero
+.Cm ClientAliveCountMax
+disables connection termination.
 .It Cm ClientAliveInterval
 Sets a timeout interval in seconds after which if no data has been received
 from the client,