Add an "ABANDONED" channel state and use for mux sessions that are

disconnected via the ~. escape sequence.  Channels in this state will
be able to close if the server responds, but do not count as active channels.
This means that if you ~. all of the mux clients when using ControlPersist
on a broken network, the backgrounded mux master will exit when the
Control Persist time expires rather than hanging around indefinitely.
bz#1917, also reported and tested by tedu@.  ok djm@ markus@.

3 files changed, 13 insertions, 5 deletions

diff --git a/usr.bin/ssh/channels.c b/usr.bin/ssh/channels.c
index b8f80b14f19..885b57740d7 100644
--- a/usr.bin/ssh/channels.c
+++ b/usr.bin/ssh/channels.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: channels.c,v 1.322 2013/06/01 13:15:51 dtucker Exp $ */
+/* $OpenBSD: channels.c,v 1.323 2013/06/07 15:37:52 dtucker Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -209,6 +209,7 @@ channel_lookup(int id)
 	case SSH_CHANNEL_OPEN:
 	case SSH_CHANNEL_INPUT_DRAINING:
 	case SSH_CHANNEL_OUTPUT_DRAINING:
+	case SSH_CHANNEL_ABANDONED:
 		return (c);
 	}
 	logit("Non-public channel %d, type %d.", id, c->type);
@@ -525,6 +526,7 @@ channel_still_open(void)
 		case SSH_CHANNEL_DYNAMIC:
 		case SSH_CHANNEL_CONNECTING:
 		case SSH_CHANNEL_ZOMBIE:
+		case SSH_CHANNEL_ABANDONED:
 			continue;
 		case SSH_CHANNEL_LARVAL:
 			if (!compat20)
@@ -570,6 +572,7 @@ channel_find_open(void)
 		case SSH_CHANNEL_OPENING:
 		case SSH_CHANNEL_CONNECTING:
 		case SSH_CHANNEL_ZOMBIE:
+		case SSH_CHANNEL_ABANDONED:
 			continue;
 		case SSH_CHANNEL_LARVAL:
 		case SSH_CHANNEL_AUTH_SOCKET:
@@ -617,6 +620,7 @@ channel_open_message(void)
 		case SSH_CHANNEL_CLOSED:
 		case SSH_CHANNEL_AUTH_SOCKET:
 		case SSH_CHANNEL_ZOMBIE:
+		case SSH_CHANNEL_ABANDONED:
 		case SSH_CHANNEL_MUX_CLIENT:
 		case SSH_CHANNEL_MUX_LISTENER:
 			continue;
@@ -2469,7 +2473,7 @@ channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
 	if (c == NULL)
 		packet_disconnect("Received close confirmation for "
 		    "out-of-range channel %d.", id);
-	if (c->type != SSH_CHANNEL_CLOSED)
+	if (c->type != SSH_CHANNEL_CLOSED && c->type != SSH_CHANNEL_ABANDONED)
 		packet_disconnect("Received close confirmation for "
 		    "non-closed channel %d (type %d).", id, c->type);
 	channel_free(c);
diff --git a/usr.bin/ssh/channels.h b/usr.bin/ssh/channels.h
index 97035756e4e..9e5fe0e8bc1 100644
--- a/usr.bin/ssh/channels.h
+++ b/usr.bin/ssh/channels.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: channels.h,v 1.112 2013/06/02 21:01:51 dtucker Exp $ */
+/* $OpenBSD: channels.h,v 1.113 2013/06/07 15:37:52 dtucker Exp $ */
 
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
@@ -55,7 +55,8 @@
 #define SSH_CHANNEL_ZOMBIE		14	/* Almost dead. */
 #define SSH_CHANNEL_MUX_LISTENER	15	/* Listener for mux conn. */
 #define SSH_CHANNEL_MUX_CLIENT		16	/* Conn. to mux slave */
-#define SSH_CHANNEL_MAX_TYPE		17
+#define SSH_CHANNEL_ABANDONED		17	/* Abandoned session, eg mux */
+#define SSH_CHANNEL_MAX_TYPE		18
 
 #define CHANNEL_CANCEL_PORT_STATIC	-1
 
diff --git a/usr.bin/ssh/clientloop.c b/usr.bin/ssh/clientloop.c
index cffb2fe81a0..ba6dd36705b 100644
--- a/usr.bin/ssh/clientloop.c
+++ b/usr.bin/ssh/clientloop.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: clientloop.c,v 1.252 2013/06/02 23:36:29 dtucker Exp $ */
+/* $OpenBSD: clientloop.c,v 1.253 2013/06/07 15:37:52 dtucker Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -1102,6 +1102,9 @@ process_escapes(Channel *c, Buffer *bin, Buffer *bout, Buffer *berr,
 					chan_write_failed(c);
 					if (c->detach_user)
 						c->detach_user(c->self, NULL);
+					c->type = SSH_CHANNEL_ABANDONED;
+					buffer_clear(&c->input);
+					chan_ibuf_empty(c);
 					return 0;
 				} else
 					quit_pending = 1;