upstream: Reset last-seen time when sending a keepalive. Prevents

sending two keepalives successively and prematurely terminating connection
when ClientAliveCount=1.  While there, collapse two similar tests into one.
ok markus@

OpenBSD-Commit-ID: 043670d201dfe222537a2a4bed16ce1087de5ddd

1 files changed, 9 insertions, 6 deletions

diff --git a/serverloop.c b/serverloop.c
index 9602e050d..f86f832b6 100644
--- a/serverloop.c
+++ b/serverloop.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: serverloop.c,v 1.213 2019/01/19 22:30:52 djm Exp $ */
+/* $OpenBSD: serverloop.c,v 1.214 2019/03/06 21:06:59 dtucker Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -225,6 +225,7 @@ wait_until_can_do_something(struct ssh *ssh,
         int ret;
         time_t minwait_secs = 0;
         int client_alive_scheduled = 0;
+        /* time we last heard from the client OR sent a keepalive */
         static time_t last_client_time;
 
         /* Allocate and update select() masks for channel descriptors. */
@@ -293,13 +294,15 @@ wait_until_can_do_something(struct ssh *ssh,
         } else if (client_alive_scheduled) {
                 time_t now = monotime();
 
-                if (ret == 0) { /* timeout */
+                /*
+                 * If the select timed out, or returned for some other reason
+                 * but we haven't heard from the client in time, send keepalive.
+                 */
+                if (ret == 0 || (last_client_time != 0 && last_client_time +
+                    options.client_alive_interval <= now)) {
                         client_alive_check(ssh);
-                } else if (FD_ISSET(connection_in, *readsetp)) {
                         last_client_time = now;
-                } else if (last_client_time != 0 && last_client_time +
-                    options.client_alive_interval <= now) {
-                        client_alive_check(ssh);
+                } else if (FD_ISSET(connection_in, *readsetp)) {
                         last_client_time = now;
                 }
         }