Adding upstream version 1:9.2p1.upstream/1%9.2p1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2698 insertions, 0 deletions

diff --git a/clientloop.c b/clientloop.c
new file mode 100644
index 0000000..fef9efc
--- /dev/null
+++ b/clientloop.c
@@ -0,0 +1,2698 @@
+/* $OpenBSD: clientloop.c,v 1.387 2023/01/06 02:39:59 djm Exp $ */
+/*
+ * Author: Tatu Ylonen <ylo@cs.hut.fi>
+ * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
+ *                    All rights reserved
+ * The main loop for the interactive session (client side).
+ *
+ * As far as I am concerned, the code I have written for this software
+ * can be used freely for any purpose.  Any derived versions of this
+ * software must be clearly marked as such, and if the derived work is
+ * incompatible with the protocol description in the RFC file, it must be
+ * called by a name other than "ssh" or "Secure Shell".
+ *
+ *
+ * Copyright (c) 1999 Theo de Raadt.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ *
+ * SSH2 support added by Markus Friedl.
+ * Copyright (c) 1999, 2000, 2001 Markus Friedl.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "includes.h"
+
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#ifdef HAVE_SYS_STAT_H
+# include <sys/stat.h>
+#endif
+#ifdef HAVE_SYS_TIME_H
+# include <sys/time.h>
+#endif
+#include <sys/socket.h>
+
+#include <ctype.h>
+#include <errno.h>
+#ifdef HAVE_PATHS_H
+#include <paths.h>
+#endif
+#ifdef HAVE_POLL_H
+#include <poll.h>
+#endif
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdarg.h>
+#include <termios.h>
+#include <pwd.h>
+#include <unistd.h>
+#include <limits.h>
+
+#include "openbsd-compat/sys-queue.h"
+#include "xmalloc.h"
+#include "ssh.h"
+#include "ssh2.h"
+#include "packet.h"
+#include "sshbuf.h"
+#include "compat.h"
+#include "channels.h"
+#include "dispatch.h"
+#include "sshkey.h"
+#include "cipher.h"
+#include "kex.h"
+#include "myproposal.h"
+#include "log.h"
+#include "misc.h"
+#include "readconf.h"
+#include "clientloop.h"
+#include "sshconnect.h"
+#include "authfd.h"
+#include "atomicio.h"
+#include "sshpty.h"
+#include "match.h"
+#include "msg.h"
+#include "ssherr.h"
+#include "hostfile.h"
+
+/* Permitted RSA signature algorithms for UpdateHostkeys proofs */
+#define HOSTKEY_PROOF_RSA_ALGS	"rsa-sha2-512,rsa-sha2-256"
+
+/* import options */
+extern Options options;
+
+/* Control socket */
+extern int muxserver_sock; /* XXX use mux_client_cleanup() instead */
+
+/*
+ * Name of the host we are connecting to.  This is the name given on the
+ * command line, or the Hostname specified for the user-supplied name in a
+ * configuration file.
+ */
+extern char *host;
+
+/*
+ * If this field is not NULL, the ForwardAgent socket is this path and different
+ * instead of SSH_AUTH_SOCK.
+ */
+extern char *forward_agent_sock_path;
+
+/*
+ * Flag to indicate that we have received a window change signal which has
+ * not yet been processed.  This will cause a message indicating the new
+ * window size to be sent to the server a little later.  This is volatile
+ * because this is updated in a signal handler.
+ */
+static volatile sig_atomic_t received_window_change_signal = 0;
+static volatile sig_atomic_t received_signal = 0;
+
+/* Time when backgrounded control master using ControlPersist should exit */
+static time_t control_persist_exit_time = 0;
+
+/* Common data for the client loop code. */
+volatile sig_atomic_t quit_pending; /* Set non-zero to quit the loop. */
+static int last_was_cr;		/* Last character was a newline. */
+static int exit_status;		/* Used to store the command exit status. */
+static struct sshbuf *stderr_buffer;	/* Used for final exit message. */
+static int connection_in;	/* Connection to server (input). */
+static int connection_out;	/* Connection to server (output). */
+static int need_rekeying;	/* Set to non-zero if rekeying is requested. */
+static int session_closed;	/* In SSH2: login session closed. */
+static u_int x11_refuse_time;	/* If >0, refuse x11 opens after this time. */
+static time_t server_alive_time;	/* Time to do server_alive_check */
+static int hostkeys_update_complete;
+static int session_setup_complete;
+
+static void client_init_dispatch(struct ssh *ssh);
+int	session_ident = -1;
+
+/* Track escape per proto2 channel */
+struct escape_filter_ctx {
+	int escape_pending;
+	int escape_char;
+};
+
+/* Context for channel confirmation replies */
+struct channel_reply_ctx {
+	const char *request_type;
+	int id;
+	enum confirm_action action;
+};
+
+/* Global request success/failure callbacks */
+/* XXX move to struct ssh? */
+struct global_confirm {
+	TAILQ_ENTRY(global_confirm) entry;
+	global_confirm_cb *cb;
+	void *ctx;
+	int ref_count;
+};
+TAILQ_HEAD(global_confirms, global_confirm);
+static struct global_confirms global_confirms =
+    TAILQ_HEAD_INITIALIZER(global_confirms);
+
+void ssh_process_session2_setup(int, int, int, struct sshbuf *);
+static void quit_message(const char *fmt, ...)
+    __attribute__((__format__ (printf, 1, 2)));
+
+static void
+quit_message(const char *fmt, ...)
+{
+	char *msg;
+	va_list args;
+	int r;
+
+	va_start(args, fmt);
+	xvasprintf(&msg, fmt, args);
+	va_end(args);
+
+	if ((r = sshbuf_putf(stderr_buffer, "%s\r\n", msg)) != 0)
+		fatal_fr(r, "sshbuf_putf");
+	quit_pending = 1;
+}
+
+/*
+ * Signal handler for the window change signal (SIGWINCH).  This just sets a
+ * flag indicating that the window has changed.
+ */
+/*ARGSUSED */
+static void
+window_change_handler(int sig)
+{
+	received_window_change_signal = 1;
+}
+
+/*
+ * Signal handler for signals that cause the program to terminate.  These
+ * signals must be trapped to restore terminal modes.
+ */
+/*ARGSUSED */
+static void
+signal_handler(int sig)
+{
+	received_signal = sig;
+	quit_pending = 1;
+}
+
+/*
+ * Sets control_persist_exit_time to the absolute time when the
+ * backgrounded control master should exit due to expiry of the
+ * ControlPersist timeout.  Sets it to 0 if we are not a backgrounded
+ * control master process, or if there is no ControlPersist timeout.
+ */
+static void
+set_control_persist_exit_time(struct ssh *ssh)
+{
+	if (muxserver_sock == -1 || !options.control_persist
+	    || options.control_persist_timeout == 0) {
+		/* not using a ControlPersist timeout */
+		control_persist_exit_time = 0;
+	} else if (channel_still_open(ssh)) {
+		/* some client connections are still open */
+		if (control_persist_exit_time > 0)
+			debug2_f("cancel scheduled exit");
+		control_persist_exit_time = 0;
+	} else if (control_persist_exit_time <= 0) {
+		/* a client connection has recently closed */
+		control_persist_exit_time = monotime() +
+			(time_t)options.control_persist_timeout;
+		debug2_f("schedule exit in %d seconds",
+		    options.control_persist_timeout);
+	}
+	/* else we are already counting down to the timeout */
+}
+
+#define SSH_X11_VALID_DISPLAY_CHARS ":/.-_"
+static int
+client_x11_display_valid(const char *display)
+{
+	size_t i, dlen;
+
+	if (display == NULL)
+		return 0;
+
+	dlen = strlen(display);
+	for (i = 0; i < dlen; i++) {
+		if (!isalnum((u_char)display[i]) &&
+		    strchr(SSH_X11_VALID_DISPLAY_CHARS, display[i]) == NULL) {
+			debug("Invalid character '%c' in DISPLAY", display[i]);
+			return 0;
+		}
+	}
+	return 1;
+}
+
+#define SSH_X11_PROTO		"MIT-MAGIC-COOKIE-1"
+#define X11_TIMEOUT_SLACK	60
+int
+client_x11_get_proto(struct ssh *ssh, const char *display,
+    const char *xauth_path, u_int trusted, u_int timeout,
+    char **_proto, char **_data)
+{
+	char *cmd, line[512], xdisplay[512];
+	char xauthfile[PATH_MAX], xauthdir[PATH_MAX];
+	static char proto[512], data[512];
+	FILE *f;
+	int got_data = 0, generated = 0, do_unlink = 0, r;
+	struct stat st;
+	u_int now, x11_timeout_real;
+
+	*_proto = proto;
+	*_data = data;
+	proto[0] = data[0] = xauthfile[0] = xauthdir[0] = '\0';
+
+	if (!client_x11_display_valid(display)) {
+		if (display != NULL)
+			logit("DISPLAY \"%s\" invalid; disabling X11 forwarding",
+			    display);
+		return -1;
+	}
+	if (xauth_path != NULL && stat(xauth_path, &st) == -1) {
+		debug("No xauth program.");
+		xauth_path = NULL;
+	}
+
+	if (xauth_path != NULL) {
+		/*
+		 * Handle FamilyLocal case where $DISPLAY does
+		 * not match an authorization entry.  For this we
+		 * just try "xauth list unix:displaynum.screennum".
+		 * XXX: "localhost" match to determine FamilyLocal
+		 *      is not perfect.
+		 */
+		if (strncmp(display, "localhost:", 10) == 0) {
+			if ((r = snprintf(xdisplay, sizeof(xdisplay), "unix:%s",
+			    display + 10)) < 0 ||
+			    (size_t)r >= sizeof(xdisplay)) {
+				error_f("display name too long");
+				return -1;
+			}
+			display = xdisplay;
+		}
+		if (trusted == 0) {
+			/*
+			 * Generate an untrusted X11 auth cookie.
+			 *
+			 * The authentication cookie should briefly outlive
+			 * ssh's willingness to forward X11 connections to
+			 * avoid nasty fail-open behaviour in the X server.
+			 */
+			mktemp_proto(xauthdir, sizeof(xauthdir));
+			if (mkdtemp(xauthdir) == NULL) {
+				error_f("mkdtemp: %s", strerror(errno));
+				return -1;
+			}
+			do_unlink = 1;
+			if ((r = snprintf(xauthfile, sizeof(xauthfile),
+			    "%s/xauthfile", xauthdir)) < 0 ||
+			    (size_t)r >= sizeof(xauthfile)) {
+				error_f("xauthfile path too long");
+				rmdir(xauthdir);
+				return -1;
+			}
+
+			if (timeout == 0) {
+				/* auth doesn't time out */
+				xasprintf(&cmd, "%s -f %s generate %s %s "
+				    "untrusted 2>%s",
+				    xauth_path, xauthfile, display,
+				    SSH_X11_PROTO, _PATH_DEVNULL);
+			} else {
+				/* Add some slack to requested expiry */
+				if (timeout < UINT_MAX - X11_TIMEOUT_SLACK)
+					x11_timeout_real = timeout +
+					    X11_TIMEOUT_SLACK;
+				else {
+					/* Don't overflow on long timeouts */
+					x11_timeout_real = UINT_MAX;
+				}
+				xasprintf(&cmd, "%s -f %s generate %s %s "
+				    "untrusted timeout %u 2>%s",
+				    xauth_path, xauthfile, display,
+				    SSH_X11_PROTO, x11_timeout_real,
+				    _PATH_DEVNULL);
+			}
+			debug2_f("xauth command: %s", cmd);
+
+			if (timeout != 0 && x11_refuse_time == 0) {
+				now = monotime() + 1;
+				if (UINT_MAX - timeout < now)
+					x11_refuse_time = UINT_MAX;
+				else
+					x11_refuse_time = now + timeout;
+				channel_set_x11_refuse_time(ssh,
+				    x11_refuse_time);
+			}
+			if (system(cmd) == 0)
+				generated = 1;
+			free(cmd);
+		}
+
+		/*
+		 * When in untrusted mode, we read the cookie only if it was
+		 * successfully generated as an untrusted one in the step
+		 * above.
+		 */
+		if (trusted || generated) {
+			xasprintf(&cmd,
+			    "%s %s%s list %s 2>" _PATH_DEVNULL,
+			    xauth_path,
+			    generated ? "-f " : "" ,
+			    generated ? xauthfile : "",
+			    display);
+			debug2("x11_get_proto: %s", cmd);
+			f = popen(cmd, "r");
+			if (f && fgets(line, sizeof(line), f) &&
+			    sscanf(line, "%*s %511s %511s", proto, data) == 2)
+				got_data = 1;
+			if (f)
+				pclose(f);
+			free(cmd);
+		}
+	}
+
+	if (do_unlink) {
+		unlink(xauthfile);
+		rmdir(xauthdir);
+	}
+
+	/* Don't fall back to fake X11 data for untrusted forwarding */
+	if (!trusted && !got_data) {
+		error("Warning: untrusted X11 forwarding setup failed: "
+		    "xauth key data not generated");
+		return -1;
+	}
+
+	/*
+	 * If we didn't get authentication data, just make up some
+	 * data.  The forwarding code will check the validity of the
+	 * response anyway, and substitute this data.  The X11
+	 * server, however, will ignore this fake data and use
+	 * whatever authentication mechanisms it was using otherwise
+	 * for the local connection.
+	 */
+	if (!got_data) {
+		u_int8_t rnd[16];
+		u_int i;
+
+		logit("Warning: No xauth data; "
+		    "using fake authentication data for X11 forwarding.");
+		strlcpy(proto, SSH_X11_PROTO, sizeof proto);
+		arc4random_buf(rnd, sizeof(rnd));
+		for (i = 0; i < sizeof(rnd); i++) {
+			snprintf(data + 2 * i, sizeof data - 2 * i, "%02x",
+			    rnd[i]);
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Checks if the client window has changed, and sends a packet about it to
+ * the server if so.  The actual change is detected elsewhere (by a software
+ * interrupt on Unix); this just checks the flag and sends a message if
+ * appropriate.
+ */
+
+static void
+client_check_window_change(struct ssh *ssh)
+{
+	if (!received_window_change_signal)
+		return;
+	received_window_change_signal = 0;
+	debug2_f("changed");
+	channel_send_window_changes(ssh);
+}
+
+static int
+client_global_request_reply(int type, u_int32_t seq, struct ssh *ssh)
+{
+	struct global_confirm *gc;
+
+	if ((gc = TAILQ_FIRST(&global_confirms)) == NULL)
+		return 0;
+	if (gc->cb != NULL)
+		gc->cb(ssh, type, seq, gc->ctx);
+	if (--gc->ref_count <= 0) {
+		TAILQ_REMOVE(&global_confirms, gc, entry);
+		freezero(gc, sizeof(*gc));
+	}
+
+	ssh_packet_set_alive_timeouts(ssh, 0);
+	return 0;
+}
+
+static void
+schedule_server_alive_check(void)
+{
+	if (options.server_alive_interval > 0)
+		server_alive_time = monotime() + options.server_alive_interval;
+}
+
+static void
+server_alive_check(struct ssh *ssh)
+{
+	int r;
+
+	if (ssh_packet_inc_alive_timeouts(ssh) > options.server_alive_count_max) {
+		logit("Timeout, server %s not responding.", host);
+		cleanup_exit(255);
+	}
+	if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
+	    (r = sshpkt_put_cstring(ssh, "keepalive@openssh.com")) != 0 ||
+	    (r = sshpkt_put_u8(ssh, 1)) != 0 ||		/* boolean: want reply */
+	    (r = sshpkt_send(ssh)) != 0)
+		fatal_fr(r, "send packet");
+	/* Insert an empty placeholder to maintain ordering */
+	client_register_global_confirm(NULL, NULL);
+	schedule_server_alive_check();
+}
+
+/*
+ * Waits until the client can do something (some data becomes available on
+ * one of the file descriptors).
+ */
+static void
+client_wait_until_can_do_something(struct ssh *ssh, struct pollfd **pfdp,
+    u_int *npfd_allocp, u_int *npfd_activep, int rekeying,
+    int *conn_in_readyp, int *conn_out_readyp)
+{
+	struct timespec timeout;
+	int ret;
+	u_int p;
+
+	*conn_in_readyp = *conn_out_readyp = 0;
+
+	/* Prepare channel poll. First two pollfd entries are reserved */
+	ptimeout_init(&timeout);
+	channel_prepare_poll(ssh, pfdp, npfd_allocp, npfd_activep, 2, &timeout);
+	if (*npfd_activep < 2)
+		fatal_f("bad npfd %u", *npfd_activep); /* shouldn't happen */
+
+	/* channel_prepare_poll could have closed the last channel */
+	if (session_closed && !channel_still_open(ssh) &&
+	    !ssh_packet_have_data_to_write(ssh)) {
+		/* clear events since we did not call poll() */
+		for (p = 0; p < *npfd_activep; p++)
+			(*pfdp)[p].revents = 0;
+		return;
+	}
+
+	/* Monitor server connection on reserved pollfd entries */
+	(*pfdp)[0].fd = connection_in;
+	(*pfdp)[0].events = POLLIN;
+	(*pfdp)[1].fd = connection_out;
+	(*pfdp)[1].events = ssh_packet_have_data_to_write(ssh) ? POLLOUT : 0;
+
+	/*
+	 * Wait for something to happen.  This will suspend the process until
+	 * some polled descriptor can be read, written, or has some other
+	 * event pending, or a timeout expires.
+	 */
+	set_control_persist_exit_time(ssh);
+	if (control_persist_exit_time > 0)
+		ptimeout_deadline_monotime(&timeout, control_persist_exit_time);
+	if (options.server_alive_interval > 0)
+		ptimeout_deadline_monotime(&timeout, server_alive_time);
+	if (options.rekey_interval > 0 && !rekeying) {
+		ptimeout_deadline_sec(&timeout,
+		    ssh_packet_get_rekey_timeout(ssh));
+	}
+
+	ret = poll(*pfdp, *npfd_activep, ptimeout_get_ms(&timeout));
+
+	if (ret == -1) {
+		/*
+		 * We have to clear the events because we return.
+		 * We have to return, because the mainloop checks for the flags
+		 * set by the signal handlers.
+		 */
+		for (p = 0; p < *npfd_activep; p++)
+			(*pfdp)[p].revents = 0;
+		if (errno == EINTR)
+			return;
+		/* Note: we might still have data in the buffers. */
+		quit_message("poll: %s", strerror(errno));
+		return;
+	}
+
+	*conn_in_readyp = (*pfdp)[0].revents != 0;
+	*conn_out_readyp = (*pfdp)[1].revents != 0;
+
+	if (options.server_alive_interval > 0 && !*conn_in_readyp &&
+	    monotime() >= server_alive_time) {
+		/*
+		 * ServerAlive check is needed. We can't rely on the poll
+		 * timing out since traffic on the client side such as port
+		 * forwards can keep waking it up.
+		 */
+		server_alive_check(ssh);
+	}
+}
+
+static void
+client_suspend_self(struct sshbuf *bin, struct sshbuf *bout, struct sshbuf *berr)
+{
+	/* Flush stdout and stderr buffers. */
+	if (sshbuf_len(bout) > 0)
+		atomicio(vwrite, fileno(stdout), sshbuf_mutable_ptr(bout),
+		    sshbuf_len(bout));
+	if (sshbuf_len(berr) > 0)
+		atomicio(vwrite, fileno(stderr), sshbuf_mutable_ptr(berr),
+		    sshbuf_len(berr));
+
+	leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
+
+	sshbuf_reset(bin);
+	sshbuf_reset(bout);
+	sshbuf_reset(berr);
+
+	/* Send the suspend signal to the program itself. */
+	kill(getpid(), SIGTSTP);
+
+	/* Reset window sizes in case they have changed */
+	received_window_change_signal = 1;
+
+	enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
+}
+
+static void
+client_process_net_input(struct ssh *ssh)
+{
+	int r;
+
+	/*
+	 * Read input from the server, and add any such data to the buffer of
+	 * the packet subsystem.
+	 */
+	schedule_server_alive_check();
+	if ((r = ssh_packet_process_read(ssh, connection_in)) == 0)
+		return; /* success */
+	if (r == SSH_ERR_SYSTEM_ERROR) {
+		if (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK)
+			return;
+		if (errno == EPIPE) {
+			quit_message("Connection to %s closed by remote host.",
+			    host);
+			return;
+		}
+	}
+	quit_message("Read from remote host %s: %s", host, ssh_err(r));
+}
+
+static void
+client_status_confirm(struct ssh *ssh, int type, Channel *c, void *ctx)
+{
+	struct channel_reply_ctx *cr = (struct channel_reply_ctx *)ctx;
+	char errmsg[256];
+	int r, tochan;
+
+	/*
+	 * If a TTY was explicitly requested, then a failure to allocate
+	 * one is fatal.
+	 */
+	if (cr->action == CONFIRM_TTY &&
+	    (options.request_tty == REQUEST_TTY_FORCE ||
+	    options.request_tty == REQUEST_TTY_YES))
+		cr->action = CONFIRM_CLOSE;
+
+	/* XXX suppress on mux _client_ quietmode */
+	tochan = options.log_level >= SYSLOG_LEVEL_ERROR &&
+	    c->ctl_chan != -1 && c->extended_usage == CHAN_EXTENDED_WRITE;
+
+	if (type == SSH2_MSG_CHANNEL_SUCCESS) {
+		debug2("%s request accepted on channel %d",
+		    cr->request_type, c->self);
+	} else if (type == SSH2_MSG_CHANNEL_FAILURE) {
+		if (tochan) {
+			snprintf(errmsg, sizeof(errmsg),
+			    "%s request failed\r\n", cr->request_type);
+		} else {
+			snprintf(errmsg, sizeof(errmsg),
+			    "%s request failed on channel %d",
+			    cr->request_type, c->self);
+		}
+		/* If error occurred on primary session channel, then exit */
+		if (cr->action == CONFIRM_CLOSE && c->self == session_ident)
+			fatal("%s", errmsg);
+		/*
+		 * If error occurred on mux client, append to
+		 * their stderr.
+		 */
+		if (tochan) {
+			debug3_f("channel %d: mux request: %s", c->self,
+			    cr->request_type);
+			if ((r = sshbuf_put(c->extended, errmsg,
+			    strlen(errmsg))) != 0)
+				fatal_fr(r, "sshbuf_put");
+		} else
+			error("%s", errmsg);
+		if (cr->action == CONFIRM_TTY) {
+			/*
+			 * If a TTY allocation error occurred, then arrange
+			 * for the correct TTY to leave raw mode.
+			 */
+			if (c->self == session_ident)
+				leave_raw_mode(0);
+			else
+				mux_tty_alloc_failed(ssh, c);
+		} else if (cr->action == CONFIRM_CLOSE) {
+			chan_read_failed(ssh, c);
+			chan_write_failed(ssh, c);
+		}
+	}
+	free(cr);
+}
+
+static void
+client_abandon_status_confirm(struct ssh *ssh, Channel *c, void *ctx)
+{
+	free(ctx);
+}
+
+void
+client_expect_confirm(struct ssh *ssh, int id, const char *request,
+    enum confirm_action action)
+{
+	struct channel_reply_ctx *cr = xcalloc(1, sizeof(*cr));
+
+	cr->request_type = request;
+	cr->action = action;
+
+	channel_register_status_confirm(ssh, id, client_status_confirm,
+	    client_abandon_status_confirm, cr);
+}
+
+void
+client_register_global_confirm(global_confirm_cb *cb, void *ctx)
+{
+	struct global_confirm *gc, *last_gc;
+
+	/* Coalesce identical callbacks */
+	last_gc = TAILQ_LAST(&global_confirms, global_confirms);
+	if (last_gc && last_gc->cb == cb && last_gc->ctx == ctx) {
+		if (++last_gc->ref_count >= INT_MAX)
+			fatal_f("last_gc->ref_count = %d",
+			    last_gc->ref_count);
+		return;
+	}
+
+	gc = xcalloc(1, sizeof(*gc));
+	gc->cb = cb;
+	gc->ctx = ctx;
+	gc->ref_count = 1;
+	TAILQ_INSERT_TAIL(&global_confirms, gc, entry);
+}
+
+/*
+ * Returns non-zero if the client is able to handle a hostkeys-00@openssh.com
+ * hostkey update request.
+ */
+static int
+can_update_hostkeys(void)
+{
+	if (hostkeys_update_complete)
+		return 0;
+	if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK &&
+	    options.batch_mode)
+		return 0; /* won't ask in batchmode, so don't even try */
+	if (!options.update_hostkeys || options.num_user_hostfiles <= 0)
+		return 0;
+	return 1;
+}
+
+static void
+client_repledge(void)
+{
+	debug3_f("enter");
+
+	/* Might be able to tighten pledge now that session is established */
+	if (options.control_master || options.control_path != NULL ||
+	    options.forward_x11 || options.fork_after_authentication ||
+	    can_update_hostkeys() ||
+	    (session_ident != -1 && !session_setup_complete)) {
+		/* Can't tighten */
+		return;
+	}
+	/*
+	 * LocalCommand and UpdateHostkeys have finished, so can get rid of
+	 * filesystem.
+	 *
+	 * XXX protocol allows a server can to change hostkeys during the
+	 *     connection at rekey time that could trigger a hostkeys update
+	 *     but AFAIK no implementations support this. Could improve by
+	 *     forcing known_hosts to be read-only or via unveil(2).
+	 */
+	if (options.num_local_forwards != 0 ||
+	    options.num_remote_forwards != 0 ||
+	    options.num_permitted_remote_opens != 0 ||
+	    options.enable_escape_commandline != 0) {
+		/* rfwd needs inet */
+		debug("pledge: network");
+		if (pledge("stdio unix inet dns proc tty", NULL) == -1)
+			fatal_f("pledge(): %s", strerror(errno));
+	} else if (options.forward_agent != 0) {
+		/* agent forwarding needs to open $SSH_AUTH_SOCK at will */
+		debug("pledge: agent");
+		if (pledge("stdio unix proc tty", NULL) == -1)
+			fatal_f("pledge(): %s", strerror(errno));
+	} else {
+		debug("pledge: fork");
+		if (pledge("stdio proc tty", NULL) == -1)
+			fatal_f("pledge(): %s", strerror(errno));
+	}
+	/* XXX further things to do:
+	 *
+	 * - might be able to get rid of proc if we kill ~^Z
+	 * - ssh -N (no session)
+	 * - stdio forwarding
+	 * - sessions without tty
+	 */
+}
+
+static void
+process_cmdline(struct ssh *ssh)
+{
+	void (*handler)(int);
+	char *s, *cmd;
+	int ok, delete = 0, local = 0, remote = 0, dynamic = 0;
+	struct Forward fwd;
+
+	memset(&fwd, 0, sizeof(fwd));
+
+	leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
+	handler = ssh_signal(SIGINT, SIG_IGN);
+	cmd = s = read_passphrase("\r\nssh> ", RP_ECHO);
+	if (s == NULL)
+		goto out;
+	while (isspace((u_char)*s))
+		s++;
+	if (*s == '-')
+		s++;	/* Skip cmdline '-', if any */
+	if (*s == '\0')
+		goto out;
+
+	if (*s == 'h' || *s == 'H' || *s == '?') {
+		logit("Commands:");
+		logit("      -L[bind_address:]port:host:hostport    "
+		    "Request local forward");
+		logit("      -R[bind_address:]port:host:hostport    "
+		    "Request remote forward");
+		logit("      -D[bind_address:]port                  "
+		    "Request dynamic forward");
+		logit("      -KL[bind_address:]port                 "
+		    "Cancel local forward");
+		logit("      -KR[bind_address:]port                 "
+		    "Cancel remote forward");
+		logit("      -KD[bind_address:]port                 "
+		    "Cancel dynamic forward");
+		if (!options.permit_local_command)
+			goto out;
+		logit("      !args                                  "
+		    "Execute local command");
+		goto out;
+	}
+
+	if (*s == '!' && options.permit_local_command) {
+		s++;
+		ssh_local_cmd(s);
+		goto out;
+	}
+
+	if (*s == 'K') {
+		delete = 1;
+		s++;
+	}
+	if (*s == 'L')
+		local = 1;
+	else if (*s == 'R')
+		remote = 1;
+	else if (*s == 'D')
+		dynamic = 1;
+	else {
+		logit("Invalid command.");
+		goto out;
+	}
+
+	while (isspace((u_char)*++s))
+		;
+
+	/* XXX update list of forwards in options */
+	if (delete) {
+		/* We pass 1 for dynamicfwd to restrict to 1 or 2 fields. */
+		if (!parse_forward(&fwd, s, 1, 0)) {
+			logit("Bad forwarding close specification.");
+			goto out;
+		}
+		if (remote)
+			ok = channel_request_rforward_cancel(ssh, &fwd) == 0;
+		else if (dynamic)
+			ok = channel_cancel_lport_listener(ssh, &fwd,
+			    0, &options.fwd_opts) > 0;
+		else
+			ok = channel_cancel_lport_listener(ssh, &fwd,
+			    CHANNEL_CANCEL_PORT_STATIC,
+			    &options.fwd_opts) > 0;
+		if (!ok) {
+			logit("Unknown port forwarding.");
+			goto out;
+		}
+		logit("Canceled forwarding.");
+	} else {
+		/* -R specs can be both dynamic or not, so check both. */
+		if (remote) {
+			if (!parse_forward(&fwd, s, 0, remote) &&
+			    !parse_forward(&fwd, s, 1, remote)) {
+				logit("Bad remote forwarding specification.");
+				goto out;
+			}
+		} else if (!parse_forward(&fwd, s, dynamic, remote)) {
+			logit("Bad local forwarding specification.");
+			goto out;
+		}
+		if (local || dynamic) {
+			if (!channel_setup_local_fwd_listener(ssh, &fwd,
+			    &options.fwd_opts)) {
+				logit("Port forwarding failed.");
+				goto out;
+			}
+		} else {
+			if (channel_request_remote_forwarding(ssh, &fwd) < 0) {
+				logit("Port forwarding failed.");
+				goto out;
+			}
+		}
+		logit("Forwarding port.");
+	}
+
+out:
+	ssh_signal(SIGINT, handler);
+	enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
+	free(cmd);
+	free(fwd.listen_host);
+	free(fwd.listen_path);
+	free(fwd.connect_host);
+	free(fwd.connect_path);
+}
+
+/* reasons to suppress output of an escape command in help output */
+#define SUPPRESS_NEVER		0	/* never suppress, always show */
+#define SUPPRESS_MUXCLIENT	1	/* don't show in mux client sessions */
+#define SUPPRESS_MUXMASTER	2	/* don't show in mux master sessions */
+#define SUPPRESS_SYSLOG		4	/* don't show when logging to syslog */
+#define SUPPRESS_NOCMDLINE	8	/* don't show when cmdline disabled*/
+struct escape_help_text {
+	const char *cmd;
+	const char *text;
+	unsigned int flags;
+};
+static struct escape_help_text esc_txt[] = {
+    {".",  "terminate session", SUPPRESS_MUXMASTER},
+    {".",  "terminate connection (and any multiplexed sessions)",
+	SUPPRESS_MUXCLIENT},
+    {"B",  "send a BREAK to the remote system", SUPPRESS_NEVER},
+    {"C",  "open a command line", SUPPRESS_MUXCLIENT|SUPPRESS_NOCMDLINE},
+    {"R",  "request rekey", SUPPRESS_NEVER},
+    {"V/v",  "decrease/increase verbosity (LogLevel)", SUPPRESS_MUXCLIENT},
+    {"^Z", "suspend ssh", SUPPRESS_MUXCLIENT},
+    {"#",  "list forwarded connections", SUPPRESS_NEVER},
+    {"&",  "background ssh (when waiting for connections to terminate)",
+	SUPPRESS_MUXCLIENT},
+    {"?", "this message", SUPPRESS_NEVER},
+};
+
+static void
+print_escape_help(struct sshbuf *b, int escape_char, int mux_client,
+    int using_stderr)
+{
+	unsigned int i, suppress_flags;
+	int r;
+
+	if ((r = sshbuf_putf(b,
+	    "%c?\r\nSupported escape sequences:\r\n", escape_char)) != 0)
+		fatal_fr(r, "sshbuf_putf");
+
+	suppress_flags =
+	    (mux_client ? SUPPRESS_MUXCLIENT : 0) |
+	    (mux_client ? 0 : SUPPRESS_MUXMASTER) |
+	    (using_stderr ? 0 : SUPPRESS_SYSLOG) |
+	    (options.enable_escape_commandline == 0 ? SUPPRESS_NOCMDLINE : 0);
+
+	for (i = 0; i < sizeof(esc_txt)/sizeof(esc_txt[0]); i++) {
+		if (esc_txt[i].flags & suppress_flags)
+			continue;
+		if ((r = sshbuf_putf(b, " %c%-3s - %s\r\n",
+		    escape_char, esc_txt[i].cmd, esc_txt[i].text)) != 0)
+			fatal_fr(r, "sshbuf_putf");
+	}
+
+	if ((r = sshbuf_putf(b,
+	    " %c%c   - send the escape character by typing it twice\r\n"
+	    "(Note that escapes are only recognized immediately after "
+	    "newline.)\r\n", escape_char, escape_char)) != 0)
+		fatal_fr(r, "sshbuf_putf");
+}
+
+/*
+ * Process the characters one by one.
+ */
+static int
+process_escapes(struct ssh *ssh, Channel *c,
+    struct sshbuf *bin, struct sshbuf *bout, struct sshbuf *berr,
+    char *buf, int len)
+{
+	pid_t pid;
+	int r, bytes = 0;
+	u_int i;
+	u_char ch;
+	char *s;
+	struct escape_filter_ctx *efc = c->filter_ctx == NULL ?
+	    NULL : (struct escape_filter_ctx *)c->filter_ctx;
+
+	if (c->filter_ctx == NULL)
+		return 0;
+
+	if (len <= 0)
+		return (0);
+
+	for (i = 0; i < (u_int)len; i++) {
+		/* Get one character at a time. */
+		ch = buf[i];
+
+		if (efc->escape_pending) {
+			/* We have previously seen an escape character. */
+			/* Clear the flag now. */
+			efc->escape_pending = 0;
+
+			/* Process the escaped character. */
+			switch (ch) {
+			case '.':
+				/* Terminate the connection. */
+				if ((r = sshbuf_putf(berr, "%c.\r\n",
+				    efc->escape_char)) != 0)
+					fatal_fr(r, "sshbuf_putf");
+				if (c && c->ctl_chan != -1) {
+					channel_force_close(ssh, c, 1);
+					return 0;
+				} else
+					quit_pending = 1;
+				return -1;
+
+			case 'Z' - 64:
+				/* XXX support this for mux clients */
+				if (c && c->ctl_chan != -1) {
+					char b[16];
+ noescape:
+					if (ch == 'Z' - 64)
+						snprintf(b, sizeof b, "^Z");
+					else
+						snprintf(b, sizeof b, "%c", ch);
+					if ((r = sshbuf_putf(berr,
+					    "%c%s escape not available to "
+					    "multiplexed sessions\r\n",
+					    efc->escape_char, b)) != 0)
+						fatal_fr(r, "sshbuf_putf");
+					continue;
+				}
+				/* Suspend the program. Inform the user */
+				if ((r = sshbuf_putf(berr,
+				    "%c^Z [suspend ssh]\r\n",
+				    efc->escape_char)) != 0)
+					fatal_fr(r, "sshbuf_putf");
+
+				/* Restore terminal modes and suspend. */
+				client_suspend_self(bin, bout, berr);
+
+				/* We have been continued. */
+				continue;
+
+			case 'B':
+				if ((r = sshbuf_putf(berr,
+				    "%cB\r\n", efc->escape_char)) != 0)
+					fatal_fr(r, "sshbuf_putf");
+				channel_request_start(ssh, c->self, "break", 0);
+				if ((r = sshpkt_put_u32(ssh, 1000)) != 0 ||
+				    (r = sshpkt_send(ssh)) != 0)
+					fatal_fr(r, "send packet");
+				continue;
+
+			case 'R':
+				if (ssh->compat & SSH_BUG_NOREKEY)
+					logit("Server does not "
+					    "support re-keying");
+				else
+					need_rekeying = 1;
+				continue;
+
+			case 'V':
+				/* FALLTHROUGH */
+			case 'v':
+				if (c && c->ctl_chan != -1)
+					goto noescape;
+				if (!log_is_on_stderr()) {
+					if ((r = sshbuf_putf(berr,
+					    "%c%c [Logging to syslog]\r\n",
+					    efc->escape_char, ch)) != 0)
+						fatal_fr(r, "sshbuf_putf");
+					continue;
+				}
+				if (ch == 'V' && options.log_level >
+				    SYSLOG_LEVEL_QUIET)
+					log_change_level(--options.log_level);
+				if (ch == 'v' && options.log_level <
+				    SYSLOG_LEVEL_DEBUG3)
+					log_change_level(++options.log_level);
+				if ((r = sshbuf_putf(berr,
+				    "%c%c [LogLevel %s]\r\n",
+				    efc->escape_char, ch,
+				    log_level_name(options.log_level))) != 0)
+					fatal_fr(r, "sshbuf_putf");
+				continue;
+
+			case '&':
+				if (c && c->ctl_chan != -1)
+					goto noescape;
+				/*
+				 * Detach the program (continue to serve
+				 * connections, but put in background and no
+				 * more new connections).
+				 */
+				/* Restore tty modes. */
+				leave_raw_mode(
+				    options.request_tty == REQUEST_TTY_FORCE);
+
+				/* Stop listening for new connections. */
+				channel_stop_listening(ssh);
+
+				if ((r = sshbuf_putf(berr, "%c& "
+				    "[backgrounded]\n", efc->escape_char)) != 0)
+					fatal_fr(r, "sshbuf_putf");
+
+				/* Fork into background. */
+				pid = fork();
+				if (pid == -1) {
+					error("fork: %.100s", strerror(errno));
+					continue;
+				}
+				if (pid != 0) {	/* This is the parent. */
+					/* The parent just exits. */
+					exit(0);
+				}
+				/* The child continues serving connections. */
+				/* fake EOF on stdin */
+				if ((r = sshbuf_put_u8(bin, 4)) != 0)
+					fatal_fr(r, "sshbuf_put_u8");
+				return -1;
+			case '?':
+				print_escape_help(berr, efc->escape_char,
+				    (c && c->ctl_chan != -1),
+				    log_is_on_stderr());
+				continue;
+
+			case '#':
+				if ((r = sshbuf_putf(berr, "%c#\r\n",
+				    efc->escape_char)) != 0)
+					fatal_fr(r, "sshbuf_putf");
+				s = channel_open_message(ssh);
+				if ((r = sshbuf_put(berr, s, strlen(s))) != 0)
+					fatal_fr(r, "sshbuf_put");
+				free(s);
+				continue;
+
+			case 'C':
+				if (c && c->ctl_chan != -1)
+					goto noescape;
+				if (options.enable_escape_commandline == 0) {
+					if ((r = sshbuf_putf(berr,
+					    "commandline disabled\r\n")) != 0)
+						fatal_fr(r, "sshbuf_putf");
+					continue;
+				}
+				process_cmdline(ssh);
+				continue;
+
+			default:
+				if (ch != efc->escape_char) {
+					if ((r = sshbuf_put_u8(bin,
+					    efc->escape_char)) != 0)
+						fatal_fr(r, "sshbuf_put_u8");
+					bytes++;
+				}
+				/* Escaped characters fall through here */
+				break;
+			}
+		} else {
+			/*
+			 * The previous character was not an escape char.
+			 * Check if this is an escape.
+			 */
+			if (last_was_cr && ch == efc->escape_char) {
+				/*
+				 * It is. Set the flag and continue to
+				 * next character.
+				 */
+				efc->escape_pending = 1;
+				continue;
+			}
+		}
+
+		/*
+		 * Normal character.  Record whether it was a newline,
+		 * and append it to the buffer.
+		 */
+		last_was_cr = (ch == '\r' || ch == '\n');
+		if ((r = sshbuf_put_u8(bin, ch)) != 0)
+			fatal_fr(r, "sshbuf_put_u8");
+		bytes++;
+	}
+	return bytes;
+}
+
+/*
+ * Get packets from the connection input buffer, and process them as long as
+ * there are packets available.
+ *
+ * Any unknown packets received during the actual
+ * session cause the session to terminate.  This is
+ * intended to make debugging easier since no
+ * confirmations are sent.  Any compatible protocol
+ * extensions must be negotiated during the
+ * preparatory phase.
+ */
+
+static void
+client_process_buffered_input_packets(struct ssh *ssh)
+{
+	ssh_dispatch_run_fatal(ssh, DISPATCH_NONBLOCK, &quit_pending);
+}
+
+/* scan buf[] for '~' before sending data to the peer */
+
+/* Helper: allocate a new escape_filter_ctx and fill in its escape char */
+void *
+client_new_escape_filter_ctx(int escape_char)
+{
+	struct escape_filter_ctx *ret;
+
+	ret = xcalloc(1, sizeof(*ret));
+	ret->escape_pending = 0;
+	ret->escape_char = escape_char;
+	return (void *)ret;
+}
+
+/* Free the escape filter context on channel free */
+void
+client_filter_cleanup(struct ssh *ssh, int cid, void *ctx)
+{
+	free(ctx);
+}
+
+int
+client_simple_escape_filter(struct ssh *ssh, Channel *c, char *buf, int len)
+{
+	if (c->extended_usage != CHAN_EXTENDED_WRITE)
+		return 0;
+
+	return process_escapes(ssh, c, c->input, c->output, c->extended,
+	    buf, len);
+}
+
+static void
+client_channel_closed(struct ssh *ssh, int id, int force, void *arg)
+{
+	channel_cancel_cleanup(ssh, id);
+	session_closed = 1;
+	leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
+}
+
+/*
+ * Implements the interactive session with the server.  This is called after
+ * the user has been authenticated, and a command has been started on the
+ * remote host.  If escape_char != SSH_ESCAPECHAR_NONE, it is the character
+ * used as an escape character for terminating or suspending the session.
+ */
+int
+client_loop(struct ssh *ssh, int have_pty, int escape_char_arg,
+    int ssh2_chan_id)
+{
+	struct pollfd *pfd = NULL;
+	u_int npfd_alloc = 0, npfd_active = 0;
+	double start_time, total_time;
+	int r, len;
+	u_int64_t ibytes, obytes;
+	int conn_in_ready, conn_out_ready;
+
+	debug("Entering interactive session.");
+	session_ident = ssh2_chan_id;
+
+	if (options.control_master &&
+	    !option_clear_or_none(options.control_path)) {
+		debug("pledge: id");
+		if (pledge("stdio rpath wpath cpath unix inet dns recvfd sendfd proc exec id tty",
+		    NULL) == -1)
+			fatal_f("pledge(): %s", strerror(errno));
+
+	} else if (options.forward_x11 || options.permit_local_command) {
+		debug("pledge: exec");
+		if (pledge("stdio rpath wpath cpath unix inet dns proc exec tty",
+		    NULL) == -1)
+			fatal_f("pledge(): %s", strerror(errno));
+
+	} else if (options.update_hostkeys) {
+		debug("pledge: filesystem");
+		if (pledge("stdio rpath wpath cpath unix inet dns proc tty",
+		    NULL) == -1)
+			fatal_f("pledge(): %s", strerror(errno));
+
+	} else if (!option_clear_or_none(options.proxy_command) ||
+	    options.fork_after_authentication) {
+		debug("pledge: proc");
+		if (pledge("stdio cpath unix inet dns proc tty", NULL) == -1)
+			fatal_f("pledge(): %s", strerror(errno));
+
+	} else {
+		debug("pledge: network");
+		if (pledge("stdio unix inet dns proc tty", NULL) == -1)
+			fatal_f("pledge(): %s", strerror(errno));
+	}
+
+	/* might be able to tighten now */
+	client_repledge();
+
+	start_time = monotime_double();
+
+	/* Initialize variables. */
+	last_was_cr = 1;
+	exit_status = -1;
+	connection_in = ssh_packet_get_connection_in(ssh);
+	connection_out = ssh_packet_get_connection_out(ssh);
+
+	quit_pending = 0;
+
+	/* Initialize buffer. */
+	if ((stderr_buffer = sshbuf_new()) == NULL)
+		fatal_f("sshbuf_new failed");
+
+	client_init_dispatch(ssh);
+
+	/*
+	 * Set signal handlers, (e.g. to restore non-blocking mode)
+	 * but don't overwrite SIG_IGN, matches behaviour from rsh(1)
+	 */
+	if (ssh_signal(SIGHUP, SIG_IGN) != SIG_IGN)
+		ssh_signal(SIGHUP, signal_handler);
+	if (ssh_signal(SIGINT, SIG_IGN) != SIG_IGN)
+		ssh_signal(SIGINT, signal_handler);
+	if (ssh_signal(SIGQUIT, SIG_IGN) != SIG_IGN)
+		ssh_signal(SIGQUIT, signal_handler);
+	if (ssh_signal(SIGTERM, SIG_IGN) != SIG_IGN)
+		ssh_signal(SIGTERM, signal_handler);
+	ssh_signal(SIGWINCH, window_change_handler);
+
+	if (have_pty)
+		enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
+
+	if (session_ident != -1) {
+		if (escape_char_arg != SSH_ESCAPECHAR_NONE) {
+			channel_register_filter(ssh, session_ident,
+			    client_simple_escape_filter, NULL,
+			    client_filter_cleanup,
+			    client_new_escape_filter_ctx(
+			    escape_char_arg));
+		}
+		channel_register_cleanup(ssh, session_ident,
+		    client_channel_closed, 0);
+	}
+
+	schedule_server_alive_check();
+
+	/* Main loop of the client for the interactive session mode. */
+	while (!quit_pending) {
+
+		/* Process buffered packets sent by the server. */
+		client_process_buffered_input_packets(ssh);
+
+		if (session_closed && !channel_still_open(ssh))
+			break;
+
+		if (ssh_packet_is_rekeying(ssh)) {
+			debug("rekeying in progress");
+		} else if (need_rekeying) {
+			/* manual rekey request */
+			debug("need rekeying");
+			if ((r = kex_start_rekex(ssh)) != 0)
+				fatal_fr(r, "kex_start_rekex");
+			need_rekeying = 0;
+		} else {
+			/*
+			 * Make packets from buffered channel data, and
+			 * enqueue them for sending to the server.
+			 */
+			if (ssh_packet_not_very_much_data_to_write(ssh))
+				channel_output_poll(ssh);
+
+			/*
+			 * Check if the window size has changed, and buffer a
+			 * message about it to the server if so.
+			 */
+			client_check_window_change(ssh);
+
+			if (quit_pending)
+				break;
+		}
+		/*
+		 * Wait until we have something to do (something becomes
+		 * available on one of the descriptors).
+		 */
+		client_wait_until_can_do_something(ssh, &pfd, &npfd_alloc,
+		    &npfd_active, ssh_packet_is_rekeying(ssh),
+		    &conn_in_ready, &conn_out_ready);
+
+		if (quit_pending)
+			break;
+
+		/* Do channel operations. */
+		channel_after_poll(ssh, pfd, npfd_active);
+
+		/* Buffer input from the connection.  */
+		if (conn_in_ready)
+			client_process_net_input(ssh);
+
+		if (quit_pending)
+			break;
+
+		/* A timeout may have triggered rekeying */
+		if ((r = ssh_packet_check_rekey(ssh)) != 0)
+			fatal_fr(r, "cannot start rekeying");
+
+		/*
+		 * Send as much buffered packet data as possible to the
+		 * sender.
+		 */
+		if (conn_out_ready) {
+			if ((r = ssh_packet_write_poll(ssh)) != 0) {
+				sshpkt_fatal(ssh, r,
+				    "%s: ssh_packet_write_poll", __func__);
+			}
+		}
+
+		/*
+		 * If we are a backgrounded control master, and the
+		 * timeout has expired without any active client
+		 * connections, then quit.
+		 */
+		if (control_persist_exit_time > 0) {
+			if (monotime() >= control_persist_exit_time) {
+				debug("ControlPersist timeout expired");
+				break;
+			}
+		}
+	}
+	free(pfd);
+
+	/* Terminate the session. */
+
+	/* Stop watching for window change. */
+	ssh_signal(SIGWINCH, SIG_DFL);
+
+	if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 ||
+	    (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_BY_APPLICATION)) != 0 ||
+	    (r = sshpkt_put_cstring(ssh, "disconnected by user")) != 0 ||
+	    (r = sshpkt_put_cstring(ssh, "")) != 0 ||	/* language tag */
+	    (r = sshpkt_send(ssh)) != 0 ||
+	    (r = ssh_packet_write_wait(ssh)) != 0)
+		fatal_fr(r, "send disconnect");
+
+	channel_free_all(ssh);
+
+	if (have_pty)
+		leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
+
+	/*
+	 * If there was no shell or command requested, there will be no remote
+	 * exit status to be returned.  In that case, clear error code if the
+	 * connection was deliberately terminated at this end.
+	 */
+	if (options.session_type == SESSION_TYPE_NONE &&
+	    received_signal == SIGTERM) {
+		received_signal = 0;
+		exit_status = 0;
+	}
+
+	if (received_signal) {
+		verbose("Killed by signal %d.", (int) received_signal);
+		cleanup_exit(255);
+	}
+
+	/*
+	 * In interactive mode (with pseudo tty) display a message indicating
+	 * that the connection has been closed.
+	 */
+	if (have_pty && options.log_level >= SYSLOG_LEVEL_INFO)
+		quit_message("Connection to %s closed.", host);
+
+	/* Output any buffered data for stderr. */
+	if (sshbuf_len(stderr_buffer) > 0) {
+		len = atomicio(vwrite, fileno(stderr),
+		    (u_char *)sshbuf_ptr(stderr_buffer),
+		    sshbuf_len(stderr_buffer));
+		if (len < 0 || (u_int)len != sshbuf_len(stderr_buffer))
+			error("Write failed flushing stderr buffer.");
+		else if ((r = sshbuf_consume(stderr_buffer, len)) != 0)
+			fatal_fr(r, "sshbuf_consume");
+	}
+
+	/* Clear and free any buffers. */
+	sshbuf_free(stderr_buffer);
+
+	/* Report bytes transferred, and transfer rates. */
+	total_time = monotime_double() - start_time;
+	ssh_packet_get_bytes(ssh, &ibytes, &obytes);
+	verbose("Transferred: sent %llu, received %llu bytes, in %.1f seconds",
+	    (unsigned long long)obytes, (unsigned long long)ibytes, total_time);
+	if (total_time > 0)
+		verbose("Bytes per second: sent %.1f, received %.1f",
+		    obytes / total_time, ibytes / total_time);
+	/* Return the exit status of the program. */
+	debug("Exit status %d", exit_status);
+	return exit_status;
+}
+
+/*********/
+
+static Channel *
+client_request_forwarded_tcpip(struct ssh *ssh, const char *request_type,
+    int rchan, u_int rwindow, u_int rmaxpack)
+{
+	Channel *c = NULL;
+	struct sshbuf *b = NULL;
+	char *listen_address, *originator_address;
+	u_int listen_port, originator_port;
+	int r;
+
+	/* Get rest of the packet */
+	if ((r = sshpkt_get_cstring(ssh, &listen_address, NULL)) != 0 ||
+	    (r = sshpkt_get_u32(ssh, &listen_port)) != 0 ||
+	    (r = sshpkt_get_cstring(ssh, &originator_address, NULL)) != 0 ||
+	    (r = sshpkt_get_u32(ssh, &originator_port)) != 0 ||
+	    (r = sshpkt_get_end(ssh)) != 0)
+		fatal_fr(r, "parse packet");
+
+	debug_f("listen %s port %d, originator %s port %d",
+	    listen_address, listen_port, originator_address, originator_port);
+
+	if (listen_port > 0xffff)
+		error_f("invalid listen port");
+	else if (originator_port > 0xffff)
+		error_f("invalid originator port");
+	else {
+		c = channel_connect_by_listen_address(ssh,
+		    listen_address, listen_port, "forwarded-tcpip",
+		    originator_address);
+	}
+
+	if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) {
+		if ((b = sshbuf_new()) == NULL) {
+			error_f("alloc reply");
+			goto out;
+		}
+		/* reconstruct and send to muxclient */
+		if ((r = sshbuf_put_u8(b, 0)) != 0 ||	/* padlen */
+		    (r = sshbuf_put_u8(b, SSH2_MSG_CHANNEL_OPEN)) != 0 ||
+		    (r = sshbuf_put_cstring(b, request_type)) != 0 ||
+		    (r = sshbuf_put_u32(b, rchan)) != 0 ||
+		    (r = sshbuf_put_u32(b, rwindow)) != 0 ||
+		    (r = sshbuf_put_u32(b, rmaxpack)) != 0 ||
+		    (r = sshbuf_put_cstring(b, listen_address)) != 0 ||
+		    (r = sshbuf_put_u32(b, listen_port)) != 0 ||
+		    (r = sshbuf_put_cstring(b, originator_address)) != 0 ||
+		    (r = sshbuf_put_u32(b, originator_port)) != 0 ||
+		    (r = sshbuf_put_stringb(c->output, b)) != 0) {
+			error_fr(r, "compose for muxclient");
+			goto out;
+		}
+	}
+
+ out:
+	sshbuf_free(b);
+	free(originator_address);
+	free(listen_address);
+	return c;
+}
+
+static Channel *
+client_request_forwarded_streamlocal(struct ssh *ssh,
+    const char *request_type, int rchan)
+{
+	Channel *c = NULL;
+	char *listen_path;
+	int r;
+
+	/* Get the remote path. */
+	if ((r = sshpkt_get_cstring(ssh, &listen_path, NULL)) != 0 ||
+	    (r = sshpkt_get_string(ssh, NULL, NULL)) != 0 ||	/* reserved */
+	    (r = sshpkt_get_end(ssh)) != 0)
+		fatal_fr(r, "parse packet");
+
+	debug_f("request: %s", listen_path);
+
+	c = channel_connect_by_listen_path(ssh, listen_path,
+	    "forwarded-streamlocal@openssh.com", "forwarded-streamlocal");
+	free(listen_path);
+	return c;
+}
+
+static Channel *
+client_request_x11(struct ssh *ssh, const char *request_type, int rchan)
+{
+	Channel *c = NULL;
+	char *originator;
+	u_int originator_port;
+	int r, sock;
+
+	if (!options.forward_x11) {
+		error("Warning: ssh server tried X11 forwarding.");
+		error("Warning: this is probably a break-in attempt by a "
+		    "malicious server.");
+		return NULL;
+	}
+	if (x11_refuse_time != 0 && (u_int)monotime() >= x11_refuse_time) {
+		verbose("Rejected X11 connection after ForwardX11Timeout "
+		    "expired");
+		return NULL;
+	}
+	if ((r = sshpkt_get_cstring(ssh, &originator, NULL)) != 0 ||
+	    (r = sshpkt_get_u32(ssh, &originator_port)) != 0 ||
+	    (r = sshpkt_get_end(ssh)) != 0)
+		fatal_fr(r, "parse packet");
+	/* XXX check permission */
+	/* XXX range check originator port? */
+	debug("client_request_x11: request from %s %u", originator,
+	    originator_port);
+	free(originator);
+	sock = x11_connect_display(ssh);
+	if (sock < 0)
+		return NULL;
+	c = channel_new(ssh, "x11",
+	    SSH_CHANNEL_X11_OPEN, sock, sock, -1,
+	    CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1);
+	c->force_drain = 1;
+	return c;
+}
+
+static Channel *
+client_request_agent(struct ssh *ssh, const char *request_type, int rchan)
+{
+	Channel *c = NULL;
+	int r, sock;
+
+	if (!options.forward_agent) {
+		error("Warning: ssh server tried agent forwarding.");
+		error("Warning: this is probably a break-in attempt by a "
+		    "malicious server.");
+		return NULL;
+	}
+	if (forward_agent_sock_path == NULL) {
+		r = ssh_get_authentication_socket(&sock);
+	} else {
+		r = ssh_get_authentication_socket_path(forward_agent_sock_path, &sock);
+	}
+	if (r != 0) {
+		if (r != SSH_ERR_AGENT_NOT_PRESENT)
+			debug_fr(r, "ssh_get_authentication_socket");
+		return NULL;
+	}
+	if ((r = ssh_agent_bind_hostkey(sock, ssh->kex->initial_hostkey,
+	    ssh->kex->session_id, ssh->kex->initial_sig, 1)) == 0)
+		debug_f("bound agent to hostkey");
+	else
+		debug2_fr(r, "ssh_agent_bind_hostkey");
+
+	c = channel_new(ssh, "authentication agent connection",
+	    SSH_CHANNEL_OPEN, sock, sock, -1,
+	    CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0,
+	    "authentication agent connection", 1);
+	c->force_drain = 1;
+	return c;
+}
+
+char *
+client_request_tun_fwd(struct ssh *ssh, int tun_mode,
+    int local_tun, int remote_tun, channel_open_fn *cb, void *cbctx)
+{
+	Channel *c;
+	int r, fd;
+	char *ifname = NULL;
+
+	if (tun_mode == SSH_TUNMODE_NO)
+		return 0;
+
+	debug("Requesting tun unit %d in mode %d", local_tun, tun_mode);
+
+	/* Open local tunnel device */
+	if ((fd = tun_open(local_tun, tun_mode, &ifname)) == -1) {
+		error("Tunnel device open failed.");
+		return NULL;
+	}
+	debug("Tunnel forwarding using interface %s", ifname);
+
+	c = channel_new(ssh, "tun", SSH_CHANNEL_OPENING, fd, fd, -1,
+	    CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1);
+	c->datagram = 1;
+
+#if defined(SSH_TUN_FILTER)
+	if (options.tun_open == SSH_TUNMODE_POINTOPOINT)
+		channel_register_filter(ssh, c->self, sys_tun_infilter,
+		    sys_tun_outfilter, NULL, NULL);
+#endif
+
+	if (cb != NULL)
+		channel_register_open_confirm(ssh, c->self, cb, cbctx);
+
+	if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 ||
+	    (r = sshpkt_put_cstring(ssh, "tun@openssh.com")) != 0 ||
+	    (r = sshpkt_put_u32(ssh, c->self)) != 0 ||
+	    (r = sshpkt_put_u32(ssh, c->local_window_max)) != 0 ||
+	    (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 ||
+	    (r = sshpkt_put_u32(ssh, tun_mode)) != 0 ||
+	    (r = sshpkt_put_u32(ssh, remote_tun)) != 0 ||
+	    (r = sshpkt_send(ssh)) != 0)
+		sshpkt_fatal(ssh, r, "%s: send reply", __func__);
+
+	return ifname;
+}
+
+/* XXXX move to generic input handler */
+static int
+client_input_channel_open(int type, u_int32_t seq, struct ssh *ssh)
+{
+	Channel *c = NULL;
+	char *ctype = NULL;
+	int r;
+	u_int rchan;
+	size_t len;
+	u_int rmaxpack, rwindow;
+
+	if ((r = sshpkt_get_cstring(ssh, &ctype, &len)) != 0 ||
+	    (r = sshpkt_get_u32(ssh, &rchan)) != 0 ||
+	    (r = sshpkt_get_u32(ssh, &rwindow)) != 0 ||
+	    (r = sshpkt_get_u32(ssh, &rmaxpack)) != 0)
+		goto out;
+
+	debug("client_input_channel_open: ctype %s rchan %d win %d max %d",
+	    ctype, rchan, rwindow, rmaxpack);
+
+	if (strcmp(ctype, "forwarded-tcpip") == 0) {
+		c = client_request_forwarded_tcpip(ssh, ctype, rchan, rwindow,
+		    rmaxpack);
+	} else if (strcmp(ctype, "forwarded-streamlocal@openssh.com") == 0) {
+		c = client_request_forwarded_streamlocal(ssh, ctype, rchan);
+	} else if (strcmp(ctype, "x11") == 0) {
+		c = client_request_x11(ssh, ctype, rchan);
+	} else if (strcmp(ctype, "auth-agent@openssh.com") == 0) {
+		c = client_request_agent(ssh, ctype, rchan);
+	}
+	if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) {
+		debug3("proxied to downstream: %s", ctype);
+	} else if (c != NULL) {
+		debug("confirm %s", ctype);
+		c->remote_id = rchan;
+		c->have_remote_id = 1;
+		c->remote_window = rwindow;
+		c->remote_maxpacket = rmaxpack;
+		if (c->type != SSH_CHANNEL_CONNECTING) {
+			if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 ||
+			    (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
+			    (r = sshpkt_put_u32(ssh, c->self)) != 0 ||
+			    (r = sshpkt_put_u32(ssh, c->local_window)) != 0 ||
+			    (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 ||
+			    (r = sshpkt_send(ssh)) != 0)
+				sshpkt_fatal(ssh, r, "%s: send reply", __func__);
+		}
+	} else {
+		debug("failure %s", ctype);
+		if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 ||
+		    (r = sshpkt_put_u32(ssh, rchan)) != 0 ||
+		    (r = sshpkt_put_u32(ssh, SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED)) != 0 ||
+		    (r = sshpkt_put_cstring(ssh, "open failed")) != 0 ||
+		    (r = sshpkt_put_cstring(ssh, "")) != 0 ||
+		    (r = sshpkt_send(ssh)) != 0)
+			sshpkt_fatal(ssh, r, "%s: send failure", __func__);
+	}
+	r = 0;
+ out:
+	free(ctype);
+	return r;
+}
+
+static int
+client_input_channel_req(int type, u_int32_t seq, struct ssh *ssh)
+{
+	Channel *c = NULL;
+	char *rtype = NULL;
+	u_char reply;
+	u_int id, exitval;
+	int r, success = 0;
+
+	if ((r = sshpkt_get_u32(ssh, &id)) != 0)
+		return r;
+	if (id <= INT_MAX)
+		c = channel_lookup(ssh, id);
+	if (channel_proxy_upstream(c, type, seq, ssh))
+		return 0;
+	if ((r = sshpkt_get_cstring(ssh, &rtype, NULL)) != 0 ||
+	    (r = sshpkt_get_u8(ssh, &reply)) != 0)
+		goto out;
+
+	debug("client_input_channel_req: channel %u rtype %s reply %d",
+	    id, rtype, reply);
+
+	if (c == NULL) {
+		error("client_input_channel_req: channel %d: "
+		    "unknown channel", id);
+	} else if (strcmp(rtype, "eow@openssh.com") == 0) {
+		if ((r = sshpkt_get_end(ssh)) != 0)
+			goto out;
+		chan_rcvd_eow(ssh, c);
+	} else if (strcmp(rtype, "exit-status") == 0) {
+		if ((r = sshpkt_get_u32(ssh, &exitval)) != 0)
+			goto out;
+		if (c->ctl_chan != -1) {
+			mux_exit_message(ssh, c, exitval);
+			success = 1;
+		} else if ((int)id == session_ident) {
+			/* Record exit value of local session */
+			success = 1;
+			exit_status = exitval;
+		} else {
+			/* Probably for a mux channel that has already closed */
+			debug_f("no sink for exit-status on channel %d",
+			    id);
+		}
+		if ((r = sshpkt_get_end(ssh)) != 0)
+			goto out;
+	}
+	if (reply && c != NULL && !(c->flags & CHAN_CLOSE_SENT)) {
+		if (!c->have_remote_id)
+			fatal_f("channel %d: no remote_id", c->self);
+		if ((r = sshpkt_start(ssh, success ?
+		    SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE)) != 0 ||
+		    (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
+		    (r = sshpkt_send(ssh)) != 0)
+			sshpkt_fatal(ssh, r, "%s: send failure", __func__);
+	}
+	r = 0;
+ out:
+	free(rtype);
+	return r;
+}
+
+struct hostkeys_update_ctx {
+	/* The hostname and (optionally) IP address string for the server */
+	char *host_str, *ip_str;
+
+	/*
+	 * Keys received from the server and a flag for each indicating
+	 * whether they already exist in known_hosts.
+	 * keys_match is filled in by hostkeys_find() and later (for new
+	 * keys) by client_global_hostkeys_prove_confirm().
+	 */
+	struct sshkey **keys;
+	u_int *keys_match;	/* mask of HKF_MATCH_* from hostfile.h */
+	int *keys_verified;	/* flag for new keys verified by server */
+	size_t nkeys, nnew, nincomplete; /* total, new keys, incomplete match */
+
+	/*
+	 * Keys that are in known_hosts, but were not present in the update
+	 * from the server (i.e. scheduled to be deleted).
+	 * Filled in by hostkeys_find().
+	 */
+	struct sshkey **old_keys;
+	size_t nold;
+
+	/* Various special cases. */
+	int complex_hostspec;	/* wildcard or manual pattern-list host name */
+	int ca_available;	/* saw CA key for this host */
+	int old_key_seen;	/* saw old key with other name/addr */
+	int other_name_seen;	/* saw key with other name/addr */
+};
+
+static void
+hostkeys_update_ctx_free(struct hostkeys_update_ctx *ctx)
+{
+	size_t i;
+
+	if (ctx == NULL)
+		return;
+	for (i = 0; i < ctx->nkeys; i++)
+		sshkey_free(ctx->keys[i]);
+	free(ctx->keys);
+	free(ctx->keys_match);
+	free(ctx->keys_verified);
+	for (i = 0; i < ctx->nold; i++)
+		sshkey_free(ctx->old_keys[i]);
+	free(ctx->old_keys);
+	free(ctx->host_str);
+	free(ctx->ip_str);
+	free(ctx);
+}
+
+/*
+ * Returns non-zero if a known_hosts hostname list is not of a form that
+ * can be handled by UpdateHostkeys. These include wildcard hostnames and
+ * hostnames lists that do not follow the form host[,ip].
+ */
+static int
+hostspec_is_complex(const char *hosts)
+{
+	char *cp;
+
+	/* wildcard */
+	if (strchr(hosts, '*') != NULL || strchr(hosts, '?') != NULL)
+		return 1;
+	/* single host/ip = ok */
+	if ((cp = strchr(hosts, ',')) == NULL)
+		return 0;
+	/* more than two entries on the line */
+	if (strchr(cp + 1, ',') != NULL)
+		return 1;
+	/* XXX maybe parse cp+1 and ensure it is an IP? */
+	return 0;
+}
+
+/* callback to search for ctx->keys in known_hosts */
+static int
+hostkeys_find(struct hostkey_foreach_line *l, void *_ctx)
+{
+	struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx;
+	size_t i;
+	struct sshkey **tmp;
+
+	if (l->key == NULL)
+		return 0;
+	if (l->status != HKF_STATUS_MATCHED) {
+		/* Record if one of the keys appears on a non-matching line */
+		for (i = 0; i < ctx->nkeys; i++) {
+			if (sshkey_equal(l->key, ctx->keys[i])) {
+				ctx->other_name_seen = 1;
+				debug3_f("found %s key under different "
+				    "name/addr at %s:%ld",
+				    sshkey_ssh_name(ctx->keys[i]),
+				    l->path, l->linenum);
+				return 0;
+			}
+		}
+		return 0;
+	}
+	/* Don't proceed if revocation or CA markers are present */
+	/* XXX relax this */
+	if (l->marker != MRK_NONE) {
+		debug3_f("hostkeys file %s:%ld has CA/revocation marker",
+		    l->path, l->linenum);
+		ctx->complex_hostspec = 1;
+		return 0;
+	}
+
+	/* If CheckHostIP is enabled, then check for mismatched hostname/addr */
+	if (ctx->ip_str != NULL && strchr(l->hosts, ',') != NULL) {
+		if ((l->match & HKF_MATCH_HOST) == 0) {
+			/* Record if address matched a different hostname. */
+			ctx->other_name_seen = 1;
+			debug3_f("found address %s against different hostname "
+			    "at %s:%ld", ctx->ip_str, l->path, l->linenum);
+			return 0;
+		} else if ((l->match & HKF_MATCH_IP) == 0) {
+			/* Record if hostname matched a different address. */
+			ctx->other_name_seen = 1;
+			debug3_f("found hostname %s against different address "
+			    "at %s:%ld", ctx->host_str, l->path, l->linenum);
+		}
+	}
+
+	/*
+	 * UpdateHostkeys is skipped for wildcard host names and hostnames
+	 * that contain more than two entries (ssh never writes these).
+	 */
+	if (hostspec_is_complex(l->hosts)) {
+		debug3_f("hostkeys file %s:%ld complex host specification",
+		    l->path, l->linenum);
+		ctx->complex_hostspec = 1;
+		return 0;
+	}
+
+	/* Mark off keys we've already seen for this host */
+	for (i = 0; i < ctx->nkeys; i++) {
+		if (!sshkey_equal(l->key, ctx->keys[i]))
+			continue;
+		debug3_f("found %s key at %s:%ld",
+		    sshkey_ssh_name(ctx->keys[i]), l->path, l->linenum);
+		ctx->keys_match[i] |= l->match;
+		return 0;
+	}
+	/* This line contained a key that not offered by the server */
+	debug3_f("deprecated %s key at %s:%ld", sshkey_ssh_name(l->key),
+	    l->path, l->linenum);
+	if ((tmp = recallocarray(ctx->old_keys, ctx->nold, ctx->nold + 1,
+	    sizeof(*ctx->old_keys))) == NULL)
+		fatal_f("recallocarray failed nold = %zu", ctx->nold);
+	ctx->old_keys = tmp;
+	ctx->old_keys[ctx->nold++] = l->key;
+	l->key = NULL;
+
+	return 0;
+}
+
+/* callback to search for ctx->old_keys in known_hosts under other names */
+static int
+hostkeys_check_old(struct hostkey_foreach_line *l, void *_ctx)
+{
+	struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx;
+	size_t i;
+	int hashed;
+
+	/* only care about lines that *don't* match the active host spec */
+	if (l->status == HKF_STATUS_MATCHED || l->key == NULL)
+		return 0;
+
+	hashed = l->match & (HKF_MATCH_HOST_HASHED|HKF_MATCH_IP_HASHED);
+	for (i = 0; i < ctx->nold; i++) {
+		if (!sshkey_equal(l->key, ctx->old_keys[i]))
+			continue;
+		debug3_f("found deprecated %s key at %s:%ld as %s",
+		    sshkey_ssh_name(ctx->old_keys[i]), l->path, l->linenum,
+		    hashed ? "[HASHED]" : l->hosts);
+		ctx->old_key_seen = 1;
+		break;
+	}
+	return 0;
+}
+
+/*
+ * Check known_hosts files for deprecated keys under other names. Returns 0
+ * on success or -1 on failure. Updates ctx->old_key_seen if deprecated keys
+ * exist under names other than the active hostname/IP.
+ */
+static int
+check_old_keys_othernames(struct hostkeys_update_ctx *ctx)
+{
+	size_t i;
+	int r;
+
+	debug2_f("checking for %zu deprecated keys", ctx->nold);
+	for (i = 0; i < options.num_user_hostfiles; i++) {
+		debug3_f("searching %s for %s / %s",
+		    options.user_hostfiles[i], ctx->host_str,
+		    ctx->ip_str ? ctx->ip_str : "(none)");
+		if ((r = hostkeys_foreach(options.user_hostfiles[i],
+		    hostkeys_check_old, ctx, ctx->host_str, ctx->ip_str,
+		    HKF_WANT_PARSE_KEY, 0)) != 0) {
+			if (r == SSH_ERR_SYSTEM_ERROR && errno == ENOENT) {
+				debug_f("hostkeys file %s does not exist",
+				    options.user_hostfiles[i]);
+				continue;
+			}
+			error_fr(r, "hostkeys_foreach failed for %s",
+			    options.user_hostfiles[i]);
+			return -1;
+		}
+	}
+	return 0;
+}
+
+static void
+hostkey_change_preamble(LogLevel loglevel)
+{
+	do_log2(loglevel, "The server has updated its host keys.");
+	do_log2(loglevel, "These changes were verified by the server's "
+	    "existing trusted key.");
+}
+
+static void
+update_known_hosts(struct hostkeys_update_ctx *ctx)
+{
+	int r, was_raw = 0, first = 1;
+	int asking = options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK;
+	LogLevel loglevel = asking ?  SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_VERBOSE;
+	char *fp, *response;
+	size_t i;
+	struct stat sb;
+
+	for (i = 0; i < ctx->nkeys; i++) {
+		if (!ctx->keys_verified[i])
+			continue;
+		if ((fp = sshkey_fingerprint(ctx->keys[i],
+		    options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL)
+			fatal_f("sshkey_fingerprint failed");
+		if (first && asking)
+			hostkey_change_preamble(loglevel);
+		do_log2(loglevel, "Learned new hostkey: %s %s",
+		    sshkey_type(ctx->keys[i]), fp);
+		first = 0;
+		free(fp);
+	}
+	for (i = 0; i < ctx->nold; i++) {
+		if ((fp = sshkey_fingerprint(ctx->old_keys[i],
+		    options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL)
+			fatal_f("sshkey_fingerprint failed");
+		if (first && asking)
+			hostkey_change_preamble(loglevel);
+		do_log2(loglevel, "Deprecating obsolete hostkey: %s %s",
+		    sshkey_type(ctx->old_keys[i]), fp);
+		first = 0;
+		free(fp);
+	}
+	if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) {
+		if (get_saved_tio() != NULL) {
+			leave_raw_mode(1);
+			was_raw = 1;
+		}
+		response = NULL;
+		for (i = 0; !quit_pending && i < 3; i++) {
+			free(response);
+			response = read_passphrase("Accept updated hostkeys? "
+			    "(yes/no): ", RP_ECHO);
+			if (strcasecmp(response, "yes") == 0)
+				break;
+			else if (quit_pending || response == NULL ||
+			    strcasecmp(response, "no") == 0) {
+				options.update_hostkeys = 0;
+				break;
+			} else {
+				do_log2(loglevel, "Please enter "
+				    "\"yes\" or \"no\"");
+			}
+		}
+		if (quit_pending || i >= 3 || response == NULL)
+			options.update_hostkeys = 0;
+		free(response);
+		if (was_raw)
+			enter_raw_mode(1);
+	}
+	if (options.update_hostkeys == 0)
+		return;
+	/*
+	 * Now that all the keys are verified, we can go ahead and replace
+	 * them in known_hosts (assuming SSH_UPDATE_HOSTKEYS_ASK didn't
+	 * cancel the operation).
+	 */
+	for (i = 0; i < options.num_user_hostfiles; i++) {
+		/*
+		 * NB. keys are only added to hostfiles[0], for the rest we
+		 * just delete the hostname entries.
+		 */
+		if (stat(options.user_hostfiles[i], &sb) != 0) {
+			if (errno == ENOENT) {
+				debug_f("known hosts file %s does not "
+				    "exist", options.user_hostfiles[i]);
+			} else {
+				error_f("known hosts file %s "
+				    "inaccessible: %s",
+				    options.user_hostfiles[i], strerror(errno));
+			}
+			continue;
+		}
+		if ((r = hostfile_replace_entries(options.user_hostfiles[i],
+		    ctx->host_str, ctx->ip_str,
+		    i == 0 ? ctx->keys : NULL, i == 0 ? ctx->nkeys : 0,
+		    options.hash_known_hosts, 0,
+		    options.fingerprint_hash)) != 0) {
+			error_fr(r, "hostfile_replace_entries failed for %s",
+			    options.user_hostfiles[i]);
+		}
+	}
+}
+
+static void
+client_global_hostkeys_prove_confirm(struct ssh *ssh, int type,
+    u_int32_t seq, void *_ctx)
+{
+	struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx;
+	size_t i, ndone;
+	struct sshbuf *signdata;
+	int r, plaintype;
+	const u_char *sig;
+	const char *rsa_kexalg = NULL;
+	char *alg = NULL;
+	size_t siglen;
+
+	if (ctx->nnew == 0)
+		fatal_f("ctx->nnew == 0"); /* sanity */
+	if (type != SSH2_MSG_REQUEST_SUCCESS) {
+		error("Server failed to confirm ownership of "
+		    "private host keys");
+		hostkeys_update_ctx_free(ctx);
+		return;
+	}
+	if (sshkey_type_plain(sshkey_type_from_name(
+	    ssh->kex->hostkey_alg)) == KEY_RSA)
+		rsa_kexalg = ssh->kex->hostkey_alg;
+	if ((signdata = sshbuf_new()) == NULL)
+		fatal_f("sshbuf_new failed");
+	/*
+	 * Expect a signature for each of the ctx->nnew private keys we
+	 * haven't seen before. They will be in the same order as the
+	 * ctx->keys where the corresponding ctx->keys_match[i] == 0.
+	 */
+	for (ndone = i = 0; i < ctx->nkeys; i++) {
+		if (ctx->keys_match[i])
+			continue;
+		plaintype = sshkey_type_plain(ctx->keys[i]->type);
+		/* Prepare data to be signed: session ID, unique string, key */
+		sshbuf_reset(signdata);
+		if ( (r = sshbuf_put_cstring(signdata,
+		    "hostkeys-prove-00@openssh.com")) != 0 ||
+		    (r = sshbuf_put_stringb(signdata,
+		    ssh->kex->session_id)) != 0 ||
+		    (r = sshkey_puts(ctx->keys[i], signdata)) != 0)
+			fatal_fr(r, "compose signdata");
+		/* Extract and verify signature */
+		if ((r = sshpkt_get_string_direct(ssh, &sig, &siglen)) != 0) {
+			error_fr(r, "parse sig");
+			goto out;
+		}
+		if ((r = sshkey_get_sigtype(sig, siglen, &alg)) != 0) {
+			error_fr(r, "server gave unintelligible signature "
+			    "for %s key %zu", sshkey_type(ctx->keys[i]), i);
+			goto out;
+		}
+		/*
+		 * Special case for RSA keys: if a RSA hostkey was negotiated,
+		 * then use its signature type for verification of RSA hostkey
+		 * proofs. Otherwise, accept only RSA-SHA256/512 signatures.
+		 */
+		if (plaintype == KEY_RSA && rsa_kexalg == NULL &&
+		    match_pattern_list(alg, HOSTKEY_PROOF_RSA_ALGS, 0) != 1) {
+			debug_f("server used untrusted RSA signature algorithm "
+			    "%s for key %zu, disregarding", alg, i);
+			free(alg);
+			/* zap the key from the list */
+			sshkey_free(ctx->keys[i]);
+			ctx->keys[i] = NULL;
+			ndone++;
+			continue;
+		}
+		debug3_f("verify %s key %zu using sigalg %s",
+		    sshkey_type(ctx->keys[i]), i, alg);
+		free(alg);
+		if ((r = sshkey_verify(ctx->keys[i], sig, siglen,
+		    sshbuf_ptr(signdata), sshbuf_len(signdata),
+		    plaintype == KEY_RSA ? rsa_kexalg : NULL, 0, NULL)) != 0) {
+			error_fr(r, "server gave bad signature for %s key %zu",
+			    sshkey_type(ctx->keys[i]), i);
+			goto out;
+		}
+		/* Key is good. Mark it as 'seen' */
+		ctx->keys_verified[i] = 1;
+		ndone++;
+	}
+	/* Shouldn't happen */
+	if (ndone != ctx->nnew)
+		fatal_f("ndone != ctx->nnew (%zu / %zu)", ndone, ctx->nnew);
+	if ((r = sshpkt_get_end(ssh)) != 0) {
+		error_f("protocol error");
+		goto out;
+	}
+
+	/* Make the edits to known_hosts */
+	update_known_hosts(ctx);
+ out:
+	hostkeys_update_ctx_free(ctx);
+	hostkeys_update_complete = 1;
+	client_repledge();
+}
+
+/*
+ * Returns non-zero if the key is accepted by HostkeyAlgorithms.
+ * Made slightly less trivial by the multiple RSA signature algorithm names.
+ */
+static int
+key_accepted_by_hostkeyalgs(const struct sshkey *key)
+{
+	const char *ktype = sshkey_ssh_name(key);
+	const char *hostkeyalgs = options.hostkeyalgorithms;
+
+	if (key == NULL || key->type == KEY_UNSPEC)
+		return 0;
+	if (key->type == KEY_RSA &&
+	    (match_pattern_list("rsa-sha2-256", hostkeyalgs, 0) == 1 ||
+	    match_pattern_list("rsa-sha2-512", hostkeyalgs, 0) == 1))
+		return 1;
+	return match_pattern_list(ktype, hostkeyalgs, 0) == 1;
+}
+
+/*
+ * Handle hostkeys-00@openssh.com global request to inform the client of all
+ * the server's hostkeys. The keys are checked against the user's
+ * HostkeyAlgorithms preference before they are accepted.
+ */
+static int
+client_input_hostkeys(struct ssh *ssh)
+{
+	const u_char *blob = NULL;
+	size_t i, len = 0;
+	struct sshbuf *buf = NULL;
+	struct sshkey *key = NULL, **tmp;
+	int r, prove_sent = 0;
+	char *fp;
+	static int hostkeys_seen = 0; /* XXX use struct ssh */
+	extern struct sockaddr_storage hostaddr; /* XXX from ssh.c */
+	struct hostkeys_update_ctx *ctx = NULL;
+	u_int want;
+
+	if (hostkeys_seen)
+		fatal_f("server already sent hostkeys");
+	if (!can_update_hostkeys())
+		return 1;
+	hostkeys_seen = 1;
+
+	ctx = xcalloc(1, sizeof(*ctx));
+	while (ssh_packet_remaining(ssh) > 0) {
+		sshkey_free(key);
+		key = NULL;
+		if ((r = sshpkt_get_string_direct(ssh, &blob, &len)) != 0) {
+			error_fr(r, "parse key");
+			goto out;
+		}
+		if ((r = sshkey_from_blob(blob, len, &key)) != 0) {
+			do_log2_fr(r, r == SSH_ERR_KEY_TYPE_UNKNOWN ?
+			    SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_ERROR,
+			    "convert key");
+			continue;
+		}
+		fp = sshkey_fingerprint(key, options.fingerprint_hash,
+		    SSH_FP_DEFAULT);
+		debug3_f("received %s key %s", sshkey_type(key), fp);
+		free(fp);
+
+		if (!key_accepted_by_hostkeyalgs(key)) {
+			debug3_f("%s key not permitted by "
+			    "HostkeyAlgorithms", sshkey_ssh_name(key));
+			continue;
+		}
+		/* Skip certs */
+		if (sshkey_is_cert(key)) {
+			debug3_f("%s key is a certificate; skipping",
+			    sshkey_ssh_name(key));
+			continue;
+		}
+		/* Ensure keys are unique */
+		for (i = 0; i < ctx->nkeys; i++) {
+			if (sshkey_equal(key, ctx->keys[i])) {
+				error_f("received duplicated %s host key",
+				    sshkey_ssh_name(key));
+				goto out;
+			}
+		}
+		/* Key is good, record it */
+		if ((tmp = recallocarray(ctx->keys, ctx->nkeys, ctx->nkeys + 1,
+		    sizeof(*ctx->keys))) == NULL)
+			fatal_f("recallocarray failed nkeys = %zu",
+			    ctx->nkeys);
+		ctx->keys = tmp;
+		ctx->keys[ctx->nkeys++] = key;
+		key = NULL;
+	}
+
+	if (ctx->nkeys == 0) {
+		debug_f("server sent no hostkeys");
+		goto out;
+	}
+
+	if ((ctx->keys_match = calloc(ctx->nkeys,
+	    sizeof(*ctx->keys_match))) == NULL ||
+	    (ctx->keys_verified = calloc(ctx->nkeys,
+	    sizeof(*ctx->keys_verified))) == NULL)
+		fatal_f("calloc failed");
+
+	get_hostfile_hostname_ipaddr(host,
+	    options.check_host_ip ? (struct sockaddr *)&hostaddr : NULL,
+	    options.port, &ctx->host_str,
+	    options.check_host_ip ? &ctx->ip_str : NULL);
+
+	/* Find which keys we already know about. */
+	for (i = 0; i < options.num_user_hostfiles; i++) {
+		debug_f("searching %s for %s / %s",
+		    options.user_hostfiles[i], ctx->host_str,
+		    ctx->ip_str ? ctx->ip_str : "(none)");
+		if ((r = hostkeys_foreach(options.user_hostfiles[i],
+		    hostkeys_find, ctx, ctx->host_str, ctx->ip_str,
+		    HKF_WANT_PARSE_KEY, 0)) != 0) {
+			if (r == SSH_ERR_SYSTEM_ERROR && errno == ENOENT) {
+				debug_f("hostkeys file %s does not exist",
+				    options.user_hostfiles[i]);
+				continue;
+			}
+			error_fr(r, "hostkeys_foreach failed for %s",
+			    options.user_hostfiles[i]);
+			goto out;
+		}
+	}
+
+	/* Figure out if we have any new keys to add */
+	ctx->nnew = ctx->nincomplete = 0;
+	want = HKF_MATCH_HOST | ( options.check_host_ip ? HKF_MATCH_IP : 0);
+	for (i = 0; i < ctx->nkeys; i++) {
+		if (ctx->keys_match[i] == 0)
+			ctx->nnew++;
+		if ((ctx->keys_match[i] & want) != want)
+			ctx->nincomplete++;
+	}
+
+	debug3_f("%zu server keys: %zu new, %zu retained, "
+	    "%zu incomplete match. %zu to remove", ctx->nkeys, ctx->nnew,
+	    ctx->nkeys - ctx->nnew - ctx->nincomplete,
+	    ctx->nincomplete, ctx->nold);
+
+	if (ctx->nnew == 0 && ctx->nold == 0) {
+		debug_f("no new or deprecated keys from server");
+		goto out;
+	}
+
+	/* Various reasons why we cannot proceed with the update */
+	if (ctx->complex_hostspec) {
+		debug_f("CA/revocation marker, manual host list or wildcard "
+		    "host pattern found, skipping UserKnownHostsFile update");
+		goto out;
+	}
+	if (ctx->other_name_seen) {
+		debug_f("host key found matching a different name/address, "
+		    "skipping UserKnownHostsFile update");
+		goto out;
+	}
+	/*
+	 * If removing keys, check whether they appear under different
+	 * names/addresses and refuse to proceed if they do. This avoids
+	 * cases such as hosts with multiple names becoming inconsistent
+	 * with regards to CheckHostIP entries.
+	 * XXX UpdateHostkeys=force to override this (and other) checks?
+	 */
+	if (ctx->nold != 0) {
+		if (check_old_keys_othernames(ctx) != 0)
+			goto out; /* error already logged */
+		if (ctx->old_key_seen) {
+			debug_f("key(s) for %s%s%s exist under other names; "
+			    "skipping UserKnownHostsFile update",
+			    ctx->host_str, ctx->ip_str == NULL ? "" : ",",
+			    ctx->ip_str == NULL ? "" : ctx->ip_str);
+			goto out;
+		}
+	}
+
+	if (ctx->nnew == 0) {
+		/*
+		 * We have some keys to remove or fix matching for.
+		 * We can proceed to do this without requiring a fresh proof
+		 * from the server.
+		 */
+		update_known_hosts(ctx);
+		goto out;
+	}
+	/*
+	 * We have received previously-unseen keys from the server.
+	 * Ask the server to confirm ownership of the private halves.
+	 */
+	debug3_f("asking server to prove ownership for %zu keys", ctx->nnew);
+	if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
+	    (r = sshpkt_put_cstring(ssh,
+	    "hostkeys-prove-00@openssh.com")) != 0 ||
+	    (r = sshpkt_put_u8(ssh, 1)) != 0) /* bool: want reply */
+		fatal_fr(r, "prepare hostkeys-prove");
+	if ((buf = sshbuf_new()) == NULL)
+		fatal_f("sshbuf_new");
+	for (i = 0; i < ctx->nkeys; i++) {
+		if (ctx->keys_match[i])
+			continue;
+		sshbuf_reset(buf);
+		if ((r = sshkey_putb(ctx->keys[i], buf)) != 0 ||
+		    (r = sshpkt_put_stringb(ssh, buf)) != 0)
+			fatal_fr(r, "assemble hostkeys-prove");
+	}
+	if ((r = sshpkt_send(ssh)) != 0)
+		fatal_fr(r, "send hostkeys-prove");
+	client_register_global_confirm(
+	    client_global_hostkeys_prove_confirm, ctx);
+	ctx = NULL;  /* will be freed in callback */
+	prove_sent = 1;
+
+	/* Success */
+ out:
+	hostkeys_update_ctx_free(ctx);
+	sshkey_free(key);
+	sshbuf_free(buf);
+	if (!prove_sent) {
+		/* UpdateHostkeys handling completed */
+		hostkeys_update_complete = 1;
+		client_repledge();
+	}
+	/*
+	 * NB. Return success for all cases. The server doesn't need to know
+	 * what the client does with its hosts file.
+	 */
+	return 1;
+}
+
+static int
+client_input_global_request(int type, u_int32_t seq, struct ssh *ssh)
+{
+	char *rtype;
+	u_char want_reply;
+	int r, success = 0;
+
+	if ((r = sshpkt_get_cstring(ssh, &rtype, NULL)) != 0 ||
+	    (r = sshpkt_get_u8(ssh, &want_reply)) != 0)
+		goto out;
+	debug("client_input_global_request: rtype %s want_reply %d",
+	    rtype, want_reply);
+	if (strcmp(rtype, "hostkeys-00@openssh.com") == 0)
+		success = client_input_hostkeys(ssh);
+	if (want_reply) {
+		if ((r = sshpkt_start(ssh, success ? SSH2_MSG_REQUEST_SUCCESS :
+		    SSH2_MSG_REQUEST_FAILURE)) != 0 ||
+		    (r = sshpkt_send(ssh)) != 0 ||
+		    (r = ssh_packet_write_wait(ssh)) != 0)
+			goto out;
+	}
+	r = 0;
+ out:
+	free(rtype);
+	return r;
+}
+
+static void
+client_send_env(struct ssh *ssh, int id, const char *name, const char *val)
+{
+	int r;
+
+	debug("channel %d: setting env %s = \"%s\"", id, name, val);
+	channel_request_start(ssh, id, "env", 0);
+	if ((r = sshpkt_put_cstring(ssh, name)) != 0 ||
+	    (r = sshpkt_put_cstring(ssh, val)) != 0 ||
+	    (r = sshpkt_send(ssh)) != 0)
+		fatal_fr(r, "send setenv");
+}
+
+void
+client_session2_setup(struct ssh *ssh, int id, int want_tty, int want_subsystem,
+    const char *term, struct termios *tiop, int in_fd, struct sshbuf *cmd,
+    char **env)
+{
+	size_t i, j, len;
+	int matched, r;
+	char *name, *val;
+	Channel *c = NULL;
+
+	debug2_f("id %d", id);
+
+	if ((c = channel_lookup(ssh, id)) == NULL)
+		fatal_f("channel %d: unknown channel", id);
+
+	ssh_packet_set_interactive(ssh, want_tty,
+	    options.ip_qos_interactive, options.ip_qos_bulk);
+
+	if (want_tty) {
+		struct winsize ws;
+
+		/* Store window size in the packet. */
+		if (ioctl(in_fd, TIOCGWINSZ, &ws) == -1)
+			memset(&ws, 0, sizeof(ws));
+
+		channel_request_start(ssh, id, "pty-req", 1);
+		client_expect_confirm(ssh, id, "PTY allocation", CONFIRM_TTY);
+		if ((r = sshpkt_put_cstring(ssh, term != NULL ? term : ""))
+		    != 0 ||
+		    (r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 ||
+		    (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 ||
+		    (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 ||
+		    (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0)
+			fatal_fr(r, "build pty-req");
+		if (tiop == NULL)
+			tiop = get_saved_tio();
+		ssh_tty_make_modes(ssh, -1, tiop);
+		if ((r = sshpkt_send(ssh)) != 0)
+			fatal_fr(r, "send pty-req");
+		/* XXX wait for reply */
+		c->client_tty = 1;
+	}
+
+	/* Transfer any environment variables from client to server */
+	if (options.num_send_env != 0 && env != NULL) {
+		debug("Sending environment.");
+		for (i = 0; env[i] != NULL; i++) {
+			/* Split */
+			name = xstrdup(env[i]);
+			if ((val = strchr(name, '=')) == NULL) {
+				free(name);
+				continue;
+			}
+			*val++ = '\0';
+
+			matched = 0;
+			for (j = 0; j < options.num_send_env; j++) {
+				if (match_pattern(name, options.send_env[j])) {
+					matched = 1;
+					break;
+				}
+			}
+			if (!matched) {
+				debug3("Ignored env %s", name);
+				free(name);
+				continue;
+			}
+			client_send_env(ssh, id, name, val);
+			free(name);
+		}
+	}
+	for (i = 0; i < options.num_setenv; i++) {
+		/* Split */
+		name = xstrdup(options.setenv[i]);
+		if ((val = strchr(name, '=')) == NULL) {
+			free(name);
+			continue;
+		}
+		*val++ = '\0';
+		client_send_env(ssh, id, name, val);
+		free(name);
+	}
+
+	len = sshbuf_len(cmd);
+	if (len > 0) {
+		if (len > 900)
+			len = 900;
+		if (want_subsystem) {
+			debug("Sending subsystem: %.*s",
+			    (int)len, (const u_char*)sshbuf_ptr(cmd));
+			channel_request_start(ssh, id, "subsystem", 1);
+			client_expect_confirm(ssh, id, "subsystem",
+			    CONFIRM_CLOSE);
+		} else {
+			debug("Sending command: %.*s",
+			    (int)len, (const u_char*)sshbuf_ptr(cmd));
+			channel_request_start(ssh, id, "exec", 1);
+			client_expect_confirm(ssh, id, "exec", CONFIRM_CLOSE);
+		}
+		if ((r = sshpkt_put_stringb(ssh, cmd)) != 0 ||
+		    (r = sshpkt_send(ssh)) != 0)
+			fatal_fr(r, "send command");
+	} else {
+		channel_request_start(ssh, id, "shell", 1);
+		client_expect_confirm(ssh, id, "shell", CONFIRM_CLOSE);
+		if ((r = sshpkt_send(ssh)) != 0)
+			fatal_fr(r, "send shell");
+	}
+
+	session_setup_complete = 1;
+	client_repledge();
+}
+
+static void
+client_init_dispatch(struct ssh *ssh)
+{
+	ssh_dispatch_init(ssh, &dispatch_protocol_error);
+
+	ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
+	ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_DATA, &channel_input_data);
+	ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
+	ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
+	ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open);
+	ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
+	ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
+	ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req);
+	ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
+	ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm);
+	ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm);
+	ssh_dispatch_set(ssh, SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request);
+
+	/* rekeying */
+	ssh_dispatch_set(ssh, SSH2_MSG_KEXINIT, &kex_input_kexinit);
+
+	/* global request reply messages */
+	ssh_dispatch_set(ssh, SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply);
+	ssh_dispatch_set(ssh, SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply);
+}
+
+void
+client_stop_mux(void)
+{
+	if (options.control_path != NULL && muxserver_sock != -1)
+		unlink(options.control_path);
+	/*
+	 * If we are in persist mode, or don't have a shell, signal that we
+	 * should close when all active channels are closed.
+	 */
+	if (options.control_persist || options.session_type == SESSION_TYPE_NONE) {
+		session_closed = 1;
+		setproctitle("[stopped mux]");
+	}
+}
+
+/* client specific fatal cleanup */
+void
+cleanup_exit(int i)
+{
+	leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
+	if (options.control_path != NULL && muxserver_sock != -1)
+		unlink(options.control_path);
+	ssh_kill_proxy_command();
+	_exit(i);
+}