Add channel_set_xtype()

This sets an "extended" channel type after channel creation (e.g.
"session:subsystem:sftp") that will be used for setting channel inactivity
timeouts.

ok markus dtucker

3 files changed, 38 insertions, 7 deletions

diff --git a/usr.bin/ssh/channels.c b/usr.bin/ssh/channels.c
index beeeeb4c658..1fff7bf3ef4 100644
--- a/usr.bin/ssh/channels.c
+++ b/usr.bin/ssh/channels.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: channels.c,v 1.424 2023/01/06 02:41:49 djm Exp $ */
+/* $OpenBSD: channels.c,v 1.425 2023/01/06 02:42:34 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -289,6 +289,24 @@ channel_lookup(struct ssh *ssh, int id)
 }
 
 /*
+ * Sets "extended type" of a channel; used by session layer to add additional
+ * information about channel types (e.g. shell, login, subsystem) that can then
+ * be used to select timeouts.
+ */
+void
+channel_set_xtype(struct ssh *ssh, int id, const char *xctype)
+{
+	Channel *c;
+
+	if ((c = channel_by_id(ssh, id)) == NULL)
+		fatal_f("missing channel %d", id);
+	if (c->xctype != NULL)
+		free(c->xctype);
+	c->xctype = xstrdup(xctype);
+	debug2_f("labeled channel %d as %s", id, xctype);
+}
+
+/*
  * Register filedescriptors for a channel, used when allocating a channel or
  * when the channel consumer/producer is ready, e.g. shell exec'd
  */
@@ -644,6 +662,8 @@ channel_free(struct ssh *ssh, Channel *c)
 	c->path = NULL;
 	free(c->listening_addr);
 	c->listening_addr = NULL;
+	free(c->xctype);
+	c->xctype = NULL;
 	while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) {
 		if (cc->abandon_cb != NULL)
 			cc->abandon_cb(ssh, c, cc->ctx);
@@ -859,9 +879,9 @@ channel_format_status(const Channel *c)
 {
 	char *ret = NULL;
 
-	xasprintf(&ret, "t%d %s%u i%u/%zu o%u/%zu e[%s]/%zu "
+	xasprintf(&ret, "t%d [%s] %s%u i%u/%zu o%u/%zu e[%s]/%zu "
 	    "fd %d/%d/%d sock %d cc %d io 0x%02x/0x%02x",
-	    c->type,
+	    c->type, c->xctype != NULL ? c->xctype : c->ctype,
 	    c->have_remote_id ? "r" : "nr", c->remote_id,
 	    c->istate, sshbuf_len(c->input),
 	    c->ostate, sshbuf_len(c->output),
diff --git a/usr.bin/ssh/channels.h b/usr.bin/ssh/channels.h
index c9de0aed2d4..c51c104af6a 100644
--- a/usr.bin/ssh/channels.h
+++ b/usr.bin/ssh/channels.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: channels.h,v 1.145 2023/01/06 02:39:59 djm Exp $ */
+/* $OpenBSD: channels.h,v 1.146 2023/01/06 02:42:34 djm Exp $ */
 
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
@@ -172,7 +172,8 @@ struct Channel {
 	int     extended_usage;
 	int	single_connection;
 
-	char   *ctype;		/* type */
+	char   *ctype;		/* const type - NB. not freed on channel_free */
+	char   *xctype;		/* extended type */
 
 	/* callback */
 	channel_open_fn		*open_confirm;
@@ -279,6 +280,7 @@ void	 channel_free(struct ssh *, Channel *);
 void	 channel_free_all(struct ssh *);
 void	 channel_stop_listening(struct ssh *);
 void	 channel_force_close(struct ssh *, Channel *, int);
+void	 channel_set_xtype(struct ssh *, int, const char *);
 
 void	 channel_send_open(struct ssh *, int);
 void	 channel_request_start(struct ssh *, int, char *, int);
diff --git a/usr.bin/ssh/session.c b/usr.bin/ssh/session.c
index 95f19d44c85..8d9bd02d45c 100644
--- a/usr.bin/ssh/session.c
+++ b/usr.bin/ssh/session.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: session.c,v 1.332 2023/01/06 02:41:49 djm Exp $ */
+/* $OpenBSD: session.c,v 1.333 2023/01/06 02:42:34 djm Exp $ */
 /*
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
  *                    All rights reserved
@@ -1637,7 +1637,7 @@ session_subsystem_req(struct ssh *ssh, Session *s)
 {
 	struct stat st;
 	int r, success = 0;
-	char *prog, *cmd;
+	char *prog, *cmd, *type;
 	u_int i;
 
 	if ((r = sshpkt_get_cstring(ssh, &s->subsys, NULL)) != 0 ||
@@ -1660,6 +1660,10 @@ session_subsystem_req(struct ssh *ssh, Session *s)
 				s->is_subsystem = SUBSYSTEM_EXT;
 				debug("subsystem: exec() %s", cmd);
 			}
+			xasprintf(&type, "session:subsystem:%s",
+			    options.subsystem_name[i]);
+			channel_set_xtype(ssh, s->chanid, type);
+			free(type);
 			success = do_exec(ssh, s, cmd) == 0;
 			break;
 		}
@@ -1715,6 +1719,9 @@ session_shell_req(struct ssh *ssh, Session *s)
 
 	if ((r = sshpkt_get_end(ssh)) != 0)
 		sshpkt_fatal(ssh, r, "%s: parse packet", __func__);
+
+	channel_set_xtype(ssh, s->chanid, "session:shell");
+
 	return do_exec(ssh, s, NULL) == 0;
 }
 
@@ -1729,6 +1736,8 @@ session_exec_req(struct ssh *ssh, Session *s)
 	    (r = sshpkt_get_end(ssh)) != 0)
 		sshpkt_fatal(ssh, r, "%s: parse packet", __func__);
 
+	channel_set_xtype(ssh, s->chanid, "session:command");
+
 	success = do_exec(ssh, s, command) == 0;
 	free(command);
 	return success;