Put ssh back into the repository

Change-Id: I23324372188fa6ed3f93a32b84365f5df6367590
diff --git a/ssh.c b/ssh.c
new file mode 100644
index 0000000..c717dcf
--- /dev/null
+++ b/ssh.c
@@ -0,0 +1,1588 @@
+/* $OpenBSD: ssh.c,v 1.364 2011/08/02 23:15:03 djm Exp $ */
+/*
+ * Author: Tatu Ylonen <ylo@cs.hut.fi>
+ * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
+ *                    All rights reserved
+ * Ssh client program.  This program can be used to log into a remote machine.
+ * The software supports strong authentication, encryption, and forwarding
+ * of X11, TCP/IP, and authentication connections.
+ *
+ * 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 Niels Provos.  All rights reserved.
+ * Copyright (c) 2000, 2001, 2002, 2003 Markus Friedl.  All rights reserved.
+ *
+ * Modified to work with SSL by Niels Provos <provos@citi.umich.edu>
+ * in Canada (German citizen).
+ *
+ * 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>
+#ifdef HAVE_SYS_STAT_H
+# include <sys/stat.h>
+#endif
+#include <sys/resource.h>
+#include <sys/ioctl.h>
+#include <sys/param.h>
+#include <sys/socket.h>
+#include <sys/wait.h>
+
+#include <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <netdb.h>
+#ifdef HAVE_PATHS_H
+#include <paths.h>
+#endif
+#include <pwd.h>
+#include <signal.h>
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#include <openssl/evp.h>
+#include <openssl/err.h>
+#include "openbsd-compat/openssl-compat.h"
+#include "openbsd-compat/sys-queue.h"
+
+#include "xmalloc.h"
+#include "ssh.h"
+#include "ssh1.h"
+#include "ssh2.h"
+#include "canohost.h"
+#include "compat.h"
+#include "cipher.h"
+#include "packet.h"
+#include "buffer.h"
+#include "channels.h"
+#include "key.h"
+#include "authfd.h"
+#include "authfile.h"
+#include "pathnames.h"
+#include "dispatch.h"
+#include "clientloop.h"
+#include "log.h"
+#include "readconf.h"
+#include "sshconnect.h"
+#include "misc.h"
+#include "kex.h"
+#include "mac.h"
+#include "sshpty.h"
+#include "match.h"
+#include "msg.h"
+#include "uidswap.h"
+#include "roaming.h"
+#include "version.h"
+
+#ifdef ENABLE_PKCS11
+#include "ssh-pkcs11.h"
+#endif
+
+extern char *__progname;
+
+/* Saves a copy of argv for setproctitle emulation */
+#ifndef HAVE_SETPROCTITLE
+static char **saved_av;
+#endif
+
+/* Flag indicating whether debug mode is on.  May be set on the command line. */
+int debug_flag = 0;
+
+/* Flag indicating whether a tty should be requested */
+int tty_flag = 0;
+
+/* don't exec a shell */
+int no_shell_flag = 0;
+
+/*
+ * Flag indicating that nothing should be read from stdin.  This can be set
+ * on the command line.
+ */
+int stdin_null_flag = 0;
+
+/*
+ * Flag indicating that the current process should be backgrounded and
+ * a new slave launched in the foreground for ControlPersist.
+ */
+int need_controlpersist_detach = 0;
+
+/* Copies of flags for ControlPersist foreground slave */
+int ostdin_null_flag, ono_shell_flag, otty_flag, orequest_tty;
+
+/*
+ * Flag indicating that ssh should fork after authentication.  This is useful
+ * so that the passphrase can be entered manually, and then ssh goes to the
+ * background.
+ */
+int fork_after_authentication_flag = 0;
+
+/* forward stdio to remote host and port */
+char *stdio_forward_host = NULL;
+int stdio_forward_port = 0;
+
+/*
+ * General data structure for command line options and options configurable
+ * in configuration files.  See readconf.h.
+ */
+Options options;
+
+/* optional user configfile */
+char *config = NULL;
+
+/*
+ * 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.
+ */
+char *host;
+
+/* socket address the host resolves to */
+struct sockaddr_storage hostaddr;
+
+/* Private host keys. */
+Sensitive sensitive_data;
+
+/* Original real UID. */
+uid_t original_real_uid;
+uid_t original_effective_uid;
+
+/* command to be executed */
+Buffer command;
+
+/* Should we execute a command or invoke a subsystem? */
+int subsystem_flag = 0;
+
+/* # of replies received for global requests */
+static int remote_forward_confirms_received = 0;
+
+/* mux.c */
+extern int muxserver_sock;
+extern u_int muxclient_command;
+
+/* Prints a help message to the user.  This function never returns. */
+
+static void
+usage(void)
+{
+	fprintf(stderr,
+"usage: ssh [-1246AaCfgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec]\n"
+"           [-D [bind_address:]port] [-e escape_char] [-F configfile]\n"
+"           [-I pkcs11] [-i identity_file]\n"
+"           [-L [bind_address:]port:host:hostport]\n"
+"           [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n"
+"           [-R [bind_address:]port:host:hostport] [-S ctl_path]\n"
+"           [-W host:port] [-w local_tun[:remote_tun]]\n"
+"           [user@]hostname [command]\n"
+	);
+	exit(255);
+}
+
+static int ssh_session(void);
+static int ssh_session2(void);
+static void load_public_identity_files(void);
+static void main_sigchld_handler(int);
+
+/* from muxclient.c */
+void muxclient(const char *);
+void muxserver_listen(void);
+
+/* ~/ expand a list of paths. NB. assumes path[n] is heap-allocated. */
+static void
+tilde_expand_paths(char **paths, u_int num_paths)
+{
+	u_int i;
+	char *cp;
+
+	for (i = 0; i < num_paths; i++) {
+		cp = tilde_expand_filename(paths[i], original_real_uid);
+		xfree(paths[i]);
+		paths[i] = cp;
+	}
+}
+
+/*
+ * Main program for the ssh client.
+ */
+int
+main(int ac, char **av)
+{
+	int i, r, opt, exit_status, use_syslog;
+	char *p, *cp, *line, *argv0, buf[MAXPATHLEN], *host_arg;
+	char thishost[NI_MAXHOST], shorthost[NI_MAXHOST], portstr[NI_MAXSERV];
+	struct stat st;
+	struct passwd *pw;
+	int dummy, timeout_ms;
+	extern int optind, optreset;
+	extern char *optarg;
+
+	struct servent *sp;
+	Forward fwd;
+
+	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
+	sanitise_stdfd();
+
+	__progname = ssh_get_progname(av[0]);
+
+#ifndef HAVE_SETPROCTITLE
+	/* Prepare for later setproctitle emulation */
+	/* Save argv so it isn't clobbered by setproctitle() emulation */
+	saved_av = xcalloc(ac + 1, sizeof(*saved_av));
+	for (i = 0; i < ac; i++)
+		saved_av[i] = xstrdup(av[i]);
+	saved_av[i] = NULL;
+	compat_init_setproctitle(ac, av);
+	av = saved_av;
+#endif
+
+	/*
+	 * Discard other fds that are hanging around. These can cause problem
+	 * with backgrounded ssh processes started by ControlPersist.
+	 */
+	closefrom(STDERR_FILENO + 1);
+
+	/*
+	 * Save the original real uid.  It will be needed later (uid-swapping
+	 * may clobber the real uid).
+	 */
+	original_real_uid = getuid();
+	original_effective_uid = geteuid();
+
+	/*
+	 * Use uid-swapping to give up root privileges for the duration of
+	 * option processing.  We will re-instantiate the rights when we are
+	 * ready to create the privileged port, and will permanently drop
+	 * them when the port has been created (actually, when the connection
+	 * has been made, as we may need to create the port several times).
+	 */
+	PRIV_END;
+
+#ifdef HAVE_SETRLIMIT
+	/* If we are installed setuid root be careful to not drop core. */
+	if (original_real_uid != original_effective_uid) {
+		struct rlimit rlim;
+		rlim.rlim_cur = rlim.rlim_max = 0;
+		if (setrlimit(RLIMIT_CORE, &rlim) < 0)
+			fatal("setrlimit failed: %.100s", strerror(errno));
+	}
+#endif
+	/* Get user data. */
+	pw = getpwuid(original_real_uid);
+	if (!pw) {
+		logit("You don't exist, go away!");
+		exit(255);
+	}
+	/* Take a copy of the returned structure. */
+	pw = pwcopy(pw);
+
+	/*
+	 * Set our umask to something reasonable, as some files are created
+	 * with the default umask.  This will make them world-readable but
+	 * writable only by the owner, which is ok for all files for which we
+	 * don't set the modes explicitly.
+	 */
+	umask(022);
+
+	/*
+	 * Initialize option structure to indicate that no values have been
+	 * set.
+	 */
+	initialize_options(&options);
+
+	/* Parse command-line arguments. */
+	host = NULL;
+	use_syslog = 0;
+	argv0 = av[0];
+
+ again:
+	while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
+	    "ACD:F:I:KL:MNO:PR:S:TVw:W:XYy")) != -1) {
+		switch (opt) {
+		case '1':
+			options.protocol = SSH_PROTO_1;
+			break;
+		case '2':
+			options.protocol = SSH_PROTO_2;
+			break;
+		case '4':
+			options.address_family = AF_INET;
+			break;
+		case '6':
+			options.address_family = AF_INET6;
+			break;
+		case 'n':
+			stdin_null_flag = 1;
+			break;
+		case 'f':
+			fork_after_authentication_flag = 1;
+			stdin_null_flag = 1;
+			break;
+		case 'x':
+			options.forward_x11 = 0;
+			break;
+		case 'X':
+			options.forward_x11 = 1;
+			break;
+		case 'y':
+			use_syslog = 1;
+			break;
+		case 'Y':
+			options.forward_x11 = 1;
+			options.forward_x11_trusted = 1;
+			break;
+		case 'g':
+			options.gateway_ports = 1;
+			break;
+		case 'O':
+			if (stdio_forward_host != NULL)
+				fatal("Cannot specify multiplexing "
+				    "command with -W");
+			else if (muxclient_command != 0)
+				fatal("Multiplexing command already specified");
+			if (strcmp(optarg, "check") == 0)
+				muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK;
+			else if (strcmp(optarg, "forward") == 0)
+				muxclient_command = SSHMUX_COMMAND_FORWARD;
+			else if (strcmp(optarg, "exit") == 0)
+				muxclient_command = SSHMUX_COMMAND_TERMINATE;
+			else if (strcmp(optarg, "stop") == 0)
+				muxclient_command = SSHMUX_COMMAND_STOP;
+			else
+				fatal("Invalid multiplex command.");
+			break;
+		case 'P':	/* deprecated */
+			options.use_privileged_port = 0;
+			break;
+		case 'a':
+			options.forward_agent = 0;
+			break;
+		case 'A':
+			options.forward_agent = 1;
+			break;
+		case 'k':
+			options.gss_deleg_creds = 0;
+			break;
+		case 'K':
+			options.gss_authentication = 1;
+			options.gss_deleg_creds = 1;
+			break;
+		case 'i':
+			if (stat(optarg, &st) < 0) {
+				fprintf(stderr, "Warning: Identity file %s "
+				    "not accessible: %s.\n", optarg,
+				    strerror(errno));
+				break;
+			}
+			if (options.num_identity_files >=
+			    SSH_MAX_IDENTITY_FILES)
+				fatal("Too many identity files specified "
+				    "(max %d)", SSH_MAX_IDENTITY_FILES);
+			options.identity_files[options.num_identity_files++] =
+			    xstrdup(optarg);
+			break;
+		case 'I':
+#ifdef ENABLE_PKCS11
+			options.pkcs11_provider = xstrdup(optarg);
+#else
+			fprintf(stderr, "no support for PKCS#11.\n");
+#endif
+			break;
+		case 't':
+			if (options.request_tty == REQUEST_TTY_YES)
+				options.request_tty = REQUEST_TTY_FORCE;
+			else
+				options.request_tty = REQUEST_TTY_YES;
+			break;
+		case 'v':
+			if (debug_flag == 0) {
+				debug_flag = 1;
+				options.log_level = SYSLOG_LEVEL_DEBUG1;
+			} else {
+				if (options.log_level < SYSLOG_LEVEL_DEBUG3)
+					options.log_level++;
+				break;
+			}
+			/* FALLTHROUGH */
+		case 'V':
+			fprintf(stderr, "%s, %s\n",
+			    SSH_RELEASE, SSLeay_version(SSLEAY_VERSION));
+			if (opt == 'V')
+				exit(0);
+			break;
+		case 'w':
+			if (options.tun_open == -1)
+				options.tun_open = SSH_TUNMODE_DEFAULT;
+			options.tun_local = a2tun(optarg, &options.tun_remote);
+			if (options.tun_local == SSH_TUNID_ERR) {
+				fprintf(stderr,
+				    "Bad tun device '%s'\n", optarg);
+				exit(255);
+			}
+			break;
+		case 'W':
+			if (stdio_forward_host != NULL)
+				fatal("stdio forward already specified");
+			if (muxclient_command != 0)
+				fatal("Cannot specify stdio forward with -O");
+			if (parse_forward(&fwd, optarg, 1, 0)) {
+				stdio_forward_host = fwd.listen_host;
+				stdio_forward_port = fwd.listen_port;
+				xfree(fwd.connect_host);
+			} else {
+				fprintf(stderr,
+				    "Bad stdio forwarding specification '%s'\n",
+				    optarg);
+				exit(255);
+			}
+			options.request_tty = REQUEST_TTY_NO;
+			no_shell_flag = 1;
+			options.clear_forwardings = 1;
+			options.exit_on_forward_failure = 1;
+			break;
+		case 'q':
+			options.log_level = SYSLOG_LEVEL_QUIET;
+			break;
+		case 'e':
+			if (optarg[0] == '^' && optarg[2] == 0 &&
+			    (u_char) optarg[1] >= 64 &&
+			    (u_char) optarg[1] < 128)
+				options.escape_char = (u_char) optarg[1] & 31;
+			else if (strlen(optarg) == 1)
+				options.escape_char = (u_char) optarg[0];
+			else if (strcmp(optarg, "none") == 0)
+				options.escape_char = SSH_ESCAPECHAR_NONE;
+			else {
+				fprintf(stderr, "Bad escape character '%s'.\n",
+				    optarg);
+				exit(255);
+			}
+			break;
+		case 'c':
+			if (ciphers_valid(optarg)) {
+				/* SSH2 only */
+				options.ciphers = xstrdup(optarg);
+				options.cipher = SSH_CIPHER_INVALID;
+			} else {
+				/* SSH1 only */
+				options.cipher = cipher_number(optarg);
+				if (options.cipher == -1) {
+					fprintf(stderr,
+					    "Unknown cipher type '%s'\n",
+					    optarg);
+					exit(255);
+				}
+				if (options.cipher == SSH_CIPHER_3DES)
+					options.ciphers = "3des-cbc";
+				else if (options.cipher == SSH_CIPHER_BLOWFISH)
+					options.ciphers = "blowfish-cbc";
+				else
+					options.ciphers = (char *)-1;
+			}
+			break;
+		case 'm':
+			if (mac_valid(optarg))
+				options.macs = xstrdup(optarg);
+			else {
+				fprintf(stderr, "Unknown mac type '%s'\n",
+				    optarg);
+				exit(255);
+			}
+			break;
+		case 'M':
+			if (options.control_master == SSHCTL_MASTER_YES)
+				options.control_master = SSHCTL_MASTER_ASK;
+			else
+				options.control_master = SSHCTL_MASTER_YES;
+			break;
+		case 'p':
+			options.port = a2port(optarg);
+			if (options.port <= 0) {
+				fprintf(stderr, "Bad port '%s'\n", optarg);
+				exit(255);
+			}
+			break;
+		case 'l':
+			options.user = optarg;
+			break;
+
+		case 'L':
+			if (parse_forward(&fwd, optarg, 0, 0))
+				add_local_forward(&options, &fwd);
+			else {
+				fprintf(stderr,
+				    "Bad local forwarding specification '%s'\n",
+				    optarg);
+				exit(255);
+			}
+			break;
+
+		case 'R':
+			if (parse_forward(&fwd, optarg, 0, 1)) {
+				add_remote_forward(&options, &fwd);
+			} else {
+				fprintf(stderr,
+				    "Bad remote forwarding specification "
+				    "'%s'\n", optarg);
+				exit(255);
+			}
+			break;
+
+		case 'D':
+			if (parse_forward(&fwd, optarg, 1, 0)) {
+				add_local_forward(&options, &fwd);
+			} else {
+				fprintf(stderr,
+				    "Bad dynamic forwarding specification "
+				    "'%s'\n", optarg);
+				exit(255);
+			}
+			break;
+
+		case 'C':
+			options.compression = 1;
+			break;
+		case 'N':
+			no_shell_flag = 1;
+			options.request_tty = REQUEST_TTY_NO;
+			break;
+		case 'T':
+			options.request_tty = REQUEST_TTY_NO;
+			break;
+		case 'o':
+			dummy = 1;
+			line = xstrdup(optarg);
+			if (process_config_line(&options, host ? host : "",
+			    line, "command-line", 0, &dummy) != 0)
+				exit(255);
+			xfree(line);
+			break;
+		case 's':
+			subsystem_flag = 1;
+			break;
+		case 'S':
+			if (options.control_path != NULL)
+				free(options.control_path);
+			options.control_path = xstrdup(optarg);
+			break;
+		case 'b':
+			options.bind_address = optarg;
+			break;
+		case 'F':
+			config = optarg;
+			break;
+		default:
+			usage();
+		}
+	}
+
+	ac -= optind;
+	av += optind;
+
+	if (ac > 0 && !host) {
+		if (strrchr(*av, '@')) {
+			p = xstrdup(*av);
+			cp = strrchr(p, '@');
+			if (cp == NULL || cp == p)
+				usage();
+			options.user = p;
+			*cp = '\0';
+			host = ++cp;
+		} else
+			host = *av;
+		if (ac > 1) {
+			optind = optreset = 1;
+			goto again;
+		}
+		ac--, av++;
+	}
+
+	/* Check that we got a host name. */
+	if (!host)
+		usage();
+
+	OpenSSL_add_all_algorithms();
+	ERR_load_crypto_strings();
+
+	/* Initialize the command to execute on remote host. */
+	buffer_init(&command);
+
+	if (options.request_tty == REQUEST_TTY_YES ||
+	    options.request_tty == REQUEST_TTY_FORCE)
+		tty_flag = 1;
+
+	/*
+	 * Save the command to execute on the remote host in a buffer. There
+	 * is no limit on the length of the command, except by the maximum
+	 * packet size.  Also sets the tty flag if there is no command.
+	 */
+	if (!ac) {
+		/* No command specified - execute shell on a tty. */
+		tty_flag = options.request_tty != REQUEST_TTY_NO;
+		if (subsystem_flag) {
+			fprintf(stderr,
+			    "You must specify a subsystem to invoke.\n");
+			usage();
+		}
+	} else {
+		/* A command has been specified.  Store it into the buffer. */
+		for (i = 0; i < ac; i++) {
+			if (i)
+				buffer_append(&command, " ", 1);
+			buffer_append(&command, av[i], strlen(av[i]));
+		}
+	}
+
+	/* Cannot fork to background if no command. */
+	if (fork_after_authentication_flag && buffer_len(&command) == 0 &&
+	    !no_shell_flag)
+		fatal("Cannot fork into background without a command "
+		    "to execute.");
+
+	/* Allocate a tty by default if no command specified. */
+	if (buffer_len(&command) == 0)
+		tty_flag = options.request_tty != REQUEST_TTY_NO;
+
+	/* Force no tty */
+	if (options.request_tty == REQUEST_TTY_NO || muxclient_command != 0)
+		tty_flag = 0;
+	/* Do not allocate a tty if stdin is not a tty. */
+	if ((!isatty(fileno(stdin)) || stdin_null_flag) &&
+	    options.request_tty != REQUEST_TTY_FORCE) {
+		if (tty_flag)
+			logit("Pseudo-terminal will not be allocated because "
+			    "stdin is not a terminal.");
+		tty_flag = 0;
+	}
+
+	/*
+	 * Initialize "log" output.  Since we are the client all output
+	 * actually goes to stderr.
+	 */
+	log_init(argv0,
+	    options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
+	    SYSLOG_FACILITY_USER, !use_syslog);
+
+	/*
+	 * Read per-user configuration file.  Ignore the system wide config
+	 * file if the user specifies a config file on the command line.
+	 */
+	if (config != NULL) {
+		if (!read_config_file(config, host, &options, 0))
+			fatal("Can't open user config file %.100s: "
+			    "%.100s", config, strerror(errno));
+	} else {
+		r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir,
+		    _PATH_SSH_USER_CONFFILE);
+		if (r > 0 && (size_t)r < sizeof(buf))
+			(void)read_config_file(buf, host, &options, 1);
+
+		/* Read systemwide configuration file after user config. */
+		(void)read_config_file(_PATH_HOST_CONFIG_FILE, host,
+		    &options, 0);
+	}
+
+	/* Fill configuration defaults. */
+	fill_default_options(&options);
+
+	channel_set_af(options.address_family);
+
+	/* reinit */
+	log_init(argv0, options.log_level, SYSLOG_FACILITY_USER, !use_syslog);
+
+	seed_rng();
+
+	if (options.user == NULL)
+		options.user = xstrdup(pw->pw_name);
+
+	/* Get default port if port has not been set. */
+	if (options.port == 0) {
+		sp = getservbyname(SSH_SERVICE_NAME, "tcp");
+		options.port = sp ? ntohs(sp->s_port) : SSH_DEFAULT_PORT;
+	}
+
+	/* preserve host name given on command line for %n expansion */
+	host_arg = host;
+	if (options.hostname != NULL) {
+		host = percent_expand(options.hostname,
+		    "h", host, (char *)NULL);
+	}
+
+	if (gethostname(thishost, sizeof(thishost)) == -1)
+		fatal("gethostname: %s", strerror(errno));
+	strlcpy(shorthost, thishost, sizeof(shorthost));
+	shorthost[strcspn(thishost, ".")] = '\0';
+	snprintf(portstr, sizeof(portstr), "%d", options.port);
+
+	if (options.local_command != NULL) {
+		debug3("expanding LocalCommand: %s", options.local_command);
+		cp = options.local_command;
+		options.local_command = percent_expand(cp, "d", pw->pw_dir,
+		    "h", host, "l", thishost, "n", host_arg, "r", options.user,
+		    "p", portstr, "u", pw->pw_name, "L", shorthost,
+		    (char *)NULL);
+		debug3("expanded LocalCommand: %s", options.local_command);
+		xfree(cp);
+	}
+
+	/* force lowercase for hostkey matching */
+	if (options.host_key_alias != NULL) {
+		for (p = options.host_key_alias; *p; p++)
+			if (isupper(*p))
+				*p = (char)tolower(*p);
+	}
+
+	if (options.proxy_command != NULL &&
+	    strcmp(options.proxy_command, "none") == 0) {
+		xfree(options.proxy_command);
+		options.proxy_command = NULL;
+	}
+	if (options.control_path != NULL &&
+	    strcmp(options.control_path, "none") == 0) {
+		xfree(options.control_path);
+		options.control_path = NULL;
+	}
+
+	if (options.control_path != NULL) {
+		cp = tilde_expand_filename(options.control_path,
+		    original_real_uid);
+		xfree(options.control_path);
+		options.control_path = percent_expand(cp, "h", host,
+		    "l", thishost, "n", host_arg, "r", options.user,
+		    "p", portstr, "u", pw->pw_name, "L", shorthost,
+		    (char *)NULL);
+		xfree(cp);
+	}
+	if (muxclient_command != 0 && options.control_path == NULL)
+		fatal("No ControlPath specified for \"-O\" command");
+	if (options.control_path != NULL)
+		muxclient(options.control_path);
+
+	timeout_ms = options.connection_timeout * 1000;
+
+	/* Open a connection to the remote host. */
+	if (ssh_connect(host, &hostaddr, options.port,
+	    options.address_family, options.connection_attempts, &timeout_ms,
+	    options.tcp_keep_alive, 
+#ifdef HAVE_CYGWIN
+	    options.use_privileged_port,
+#else
+	    original_effective_uid == 0 && options.use_privileged_port,
+#endif
+	    options.proxy_command) != 0)
+		exit(255);
+
+	if (timeout_ms > 0)
+		debug3("timeout: %d ms remain after connect", timeout_ms);
+
+	/*
+	 * If we successfully made the connection, load the host private key
+	 * in case we will need it later for combined rsa-rhosts
+	 * authentication. This must be done before releasing extra
+	 * privileges, because the file is only readable by root.
+	 * If we cannot access the private keys, load the public keys
+	 * instead and try to execute the ssh-keysign helper instead.
+	 */
+	sensitive_data.nkeys = 0;
+	sensitive_data.keys = NULL;
+	sensitive_data.external_keysign = 0;
+	if (options.rhosts_rsa_authentication ||
+	    options.hostbased_authentication) {
+		sensitive_data.nkeys = 7;
+		sensitive_data.keys = xcalloc(sensitive_data.nkeys,
+		    sizeof(Key));
+		for (i = 0; i < sensitive_data.nkeys; i++)
+			sensitive_data.keys[i] = NULL;
+
+		PRIV_START;
+		sensitive_data.keys[0] = key_load_private_type(KEY_RSA1,
+		    _PATH_HOST_KEY_FILE, "", NULL, NULL);
+		sensitive_data.keys[1] = key_load_private_cert(KEY_DSA,
+		    _PATH_HOST_DSA_KEY_FILE, "", NULL);
+#ifdef OPENSSL_HAS_ECC
+		sensitive_data.keys[2] = key_load_private_cert(KEY_ECDSA,
+		    _PATH_HOST_ECDSA_KEY_FILE, "", NULL);
+#endif
+		sensitive_data.keys[3] = key_load_private_cert(KEY_RSA,
+		    _PATH_HOST_RSA_KEY_FILE, "", NULL);
+		sensitive_data.keys[4] = key_load_private_type(KEY_DSA,
+		    _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL);
+#ifdef OPENSSL_HAS_ECC
+		sensitive_data.keys[5] = key_load_private_type(KEY_ECDSA,
+		    _PATH_HOST_ECDSA_KEY_FILE, "", NULL, NULL);
+#endif
+		sensitive_data.keys[6] = key_load_private_type(KEY_RSA,
+		    _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL);
+		PRIV_END;
+
+		if (options.hostbased_authentication == 1 &&
+		    sensitive_data.keys[0] == NULL &&
+		    sensitive_data.keys[4] == NULL &&
+		    sensitive_data.keys[5] == NULL &&
+		    sensitive_data.keys[6] == NULL) {
+			sensitive_data.keys[1] = key_load_cert(
+			    _PATH_HOST_DSA_KEY_FILE);
+#ifdef OPENSSL_HAS_ECC
+			sensitive_data.keys[2] = key_load_cert(
+			    _PATH_HOST_ECDSA_KEY_FILE);
+#endif
+			sensitive_data.keys[3] = key_load_cert(
+			    _PATH_HOST_RSA_KEY_FILE);
+			sensitive_data.keys[4] = key_load_public(
+			    _PATH_HOST_DSA_KEY_FILE, NULL);
+#ifdef OPENSSL_HAS_ECC
+			sensitive_data.keys[5] = key_load_public(
+			    _PATH_HOST_ECDSA_KEY_FILE, NULL);
+#endif
+			sensitive_data.keys[6] = key_load_public(
+			    _PATH_HOST_RSA_KEY_FILE, NULL);
+			sensitive_data.external_keysign = 1;
+		}
+	}
+	/*
+	 * Get rid of any extra privileges that we may have.  We will no
+	 * longer need them.  Also, extra privileges could make it very hard
+	 * to read identity files and other non-world-readable files from the
+	 * user's home directory if it happens to be on a NFS volume where
+	 * root is mapped to nobody.
+	 */
+	if (original_effective_uid == 0) {
+		PRIV_START;
+		permanently_set_uid(pw);
+	}
+
+	/*
+	 * Now that we are back to our own permissions, create ~/.ssh
+	 * directory if it doesn't already exist.
+	 */
+	r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir,
+	    strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR);
+	if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) < 0) {
+#ifdef WITH_SELINUX
+		ssh_selinux_setfscreatecon(buf);
+#endif
+		if (mkdir(buf, 0700) < 0)
+			error("Could not create directory '%.200s'.", buf);
+#ifdef WITH_SELINUX
+		ssh_selinux_setfscreatecon(NULL);
+#endif
+	}
+	/* load options.identity_files */
+	load_public_identity_files();
+
+	/* Expand ~ in known host file names. */
+	tilde_expand_paths(options.system_hostfiles,
+	    options.num_system_hostfiles);
+	tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles);
+
+	signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
+	signal(SIGCHLD, main_sigchld_handler);
+
+	/* Log into the remote system.  Never returns if the login fails. */
+	ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr,
+	    options.port, pw, timeout_ms);
+
+	if (packet_connection_is_on_socket()) {
+		verbose("Authenticated to %s ([%s]:%d).", host,
+		    get_remote_ipaddr(), get_remote_port());
+	} else {
+		verbose("Authenticated to %s (via proxy).", host);
+	}
+
+	/* We no longer need the private host keys.  Clear them now. */
+	if (sensitive_data.nkeys != 0) {
+		for (i = 0; i < sensitive_data.nkeys; i++) {
+			if (sensitive_data.keys[i] != NULL) {
+				/* Destroys contents safely */
+				debug3("clear hostkey %d", i);
+				key_free(sensitive_data.keys[i]);
+				sensitive_data.keys[i] = NULL;
+			}
+		}
+		xfree(sensitive_data.keys);
+	}
+	for (i = 0; i < options.num_identity_files; i++) {
+		if (options.identity_files[i]) {
+			xfree(options.identity_files[i]);
+			options.identity_files[i] = NULL;
+		}
+		if (options.identity_keys[i]) {
+			key_free(options.identity_keys[i]);
+			options.identity_keys[i] = NULL;
+		}
+	}
+
+	exit_status = compat20 ? ssh_session2() : ssh_session();
+	packet_close();
+
+	if (options.control_path != NULL && muxserver_sock != -1)
+		unlink(options.control_path);
+
+	/* Kill ProxyCommand if it is running. */
+	ssh_kill_proxy_command();
+
+	return exit_status;
+}
+
+static void
+control_persist_detach(void)
+{
+	pid_t pid;
+	int devnull;
+
+	debug("%s: backgrounding master process", __func__);
+
+ 	/*
+ 	 * master (current process) into the background, and make the
+ 	 * foreground process a client of the backgrounded master.
+ 	 */
+	switch ((pid = fork())) {
+	case -1:
+		fatal("%s: fork: %s", __func__, strerror(errno));
+	case 0:
+		/* Child: master process continues mainloop */
+ 		break;
+ 	default:
+		/* Parent: set up mux slave to connect to backgrounded master */
+		debug2("%s: background process is %ld", __func__, (long)pid);
+		stdin_null_flag = ostdin_null_flag;
+		options.request_tty = orequest_tty;
+		tty_flag = otty_flag;
+ 		close(muxserver_sock);
+ 		muxserver_sock = -1;
+		options.control_master = SSHCTL_MASTER_NO;
+ 		muxclient(options.control_path);
+		/* muxclient() doesn't return on success. */
+ 		fatal("Failed to connect to new control master");
+ 	}
+	if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
+		error("%s: open(\"/dev/null\"): %s", __func__,
+		    strerror(errno));
+	} else {
+		if (dup2(devnull, STDIN_FILENO) == -1 ||
+		    dup2(devnull, STDOUT_FILENO) == -1)
+			error("%s: dup2: %s", __func__, strerror(errno));
+		if (devnull > STDERR_FILENO)
+			close(devnull);
+	}
+	setproctitle("%s [mux]", options.control_path);
+}
+
+/* Do fork() after authentication. Used by "ssh -f" */
+static void
+fork_postauth(void)
+{
+	if (need_controlpersist_detach)
+		control_persist_detach();
+	debug("forking to background");
+	fork_after_authentication_flag = 0;
+	if (daemon(1, 1) < 0)
+		fatal("daemon() failed: %.200s", strerror(errno));
+}
+
+/* Callback for remote forward global requests */
+static void
+ssh_confirm_remote_forward(int type, u_int32_t seq, void *ctxt)
+{
+	Forward *rfwd = (Forward *)ctxt;
+
+	/* XXX verbose() on failure? */
+	debug("remote forward %s for: listen %d, connect %s:%d",
+	    type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
+	    rfwd->listen_port, rfwd->connect_host, rfwd->connect_port);
+	if (type == SSH2_MSG_REQUEST_SUCCESS && rfwd->listen_port == 0) {
+		rfwd->allocated_port = packet_get_int();
+		logit("Allocated port %u for remote forward to %s:%d",
+		    rfwd->allocated_port,
+		    rfwd->connect_host, rfwd->connect_port);
+	}
+	
+	if (type == SSH2_MSG_REQUEST_FAILURE) {
+		if (options.exit_on_forward_failure)
+			fatal("Error: remote port forwarding failed for "
+			    "listen port %d", rfwd->listen_port);
+		else
+			logit("Warning: remote port forwarding failed for "
+			    "listen port %d", rfwd->listen_port);
+	}
+	if (++remote_forward_confirms_received == options.num_remote_forwards) {
+		debug("All remote forwarding requests processed");
+		if (fork_after_authentication_flag)
+			fork_postauth();
+	}
+}
+
+static void
+client_cleanup_stdio_fwd(int id, void *arg)
+{
+	debug("stdio forwarding: done");
+	cleanup_exit(0);
+}
+
+static int
+client_setup_stdio_fwd(const char *host_to_connect, u_short port_to_connect)
+{
+	Channel *c;
+	int in, out;
+
+	debug3("client_setup_stdio_fwd %s:%d", host_to_connect,
+	    port_to_connect);
+
+	in = dup(STDIN_FILENO);
+	out = dup(STDOUT_FILENO);
+	if (in < 0 || out < 0)
+		fatal("channel_connect_stdio_fwd: dup() in/out failed");
+
+	if ((c = channel_connect_stdio_fwd(host_to_connect, port_to_connect,
+	    in, out)) == NULL)
+		return 0;
+	channel_register_cleanup(c->self, client_cleanup_stdio_fwd, 0);
+	return 1;
+}
+
+static void
+ssh_init_forwarding(void)
+{
+	int success = 0;
+	int i;
+
+	if (stdio_forward_host != NULL) {
+		if (!compat20) {
+			fatal("stdio forwarding require Protocol 2");
+		}
+		if (!client_setup_stdio_fwd(stdio_forward_host,
+		    stdio_forward_port))
+			fatal("Failed to connect in stdio forward mode.");
+	}
+
+	/* Initiate local TCP/IP port forwardings. */
+	for (i = 0; i < options.num_local_forwards; i++) {
+		debug("Local connections to %.200s:%d forwarded to remote "
+		    "address %.200s:%d",
+		    (options.local_forwards[i].listen_host == NULL) ?
+		    (options.gateway_ports ? "*" : "LOCALHOST") :
+		    options.local_forwards[i].listen_host,
+		    options.local_forwards[i].listen_port,
+		    options.local_forwards[i].connect_host,
+		    options.local_forwards[i].connect_port);
+		success += channel_setup_local_fwd_listener(
+		    options.local_forwards[i].listen_host,
+		    options.local_forwards[i].listen_port,
+		    options.local_forwards[i].connect_host,
+		    options.local_forwards[i].connect_port,
+		    options.gateway_ports);
+	}
+	if (i > 0 && success != i && options.exit_on_forward_failure)
+		fatal("Could not request local forwarding.");
+	if (i > 0 && success == 0)
+		error("Could not request local forwarding.");
+
+	/* Initiate remote TCP/IP port forwardings. */
+	for (i = 0; i < options.num_remote_forwards; i++) {
+		debug("Remote connections from %.200s:%d forwarded to "
+		    "local address %.200s:%d",
+		    (options.remote_forwards[i].listen_host == NULL) ?
+		    "LOCALHOST" : options.remote_forwards[i].listen_host,
+		    options.remote_forwards[i].listen_port,
+		    options.remote_forwards[i].connect_host,
+		    options.remote_forwards[i].connect_port);
+		if (channel_request_remote_forwarding(
+		    options.remote_forwards[i].listen_host,
+		    options.remote_forwards[i].listen_port,
+		    options.remote_forwards[i].connect_host,
+		    options.remote_forwards[i].connect_port) < 0) {
+			if (options.exit_on_forward_failure)
+				fatal("Could not request remote forwarding.");
+			else
+				logit("Warning: Could not request remote "
+				    "forwarding.");
+		}
+		client_register_global_confirm(ssh_confirm_remote_forward,
+		    &options.remote_forwards[i]);
+	}
+
+	/* Initiate tunnel forwarding. */
+	if (options.tun_open != SSH_TUNMODE_NO) {
+		if (client_request_tun_fwd(options.tun_open,
+		    options.tun_local, options.tun_remote) == -1) {
+			if (options.exit_on_forward_failure)
+				fatal("Could not request tunnel forwarding.");
+			else
+				error("Could not request tunnel forwarding.");
+		}
+	}			
+}
+
+static void
+check_agent_present(void)
+{
+	if (options.forward_agent) {
+		/* Clear agent forwarding if we don't have an agent. */
+		if (!ssh_agent_present())
+			options.forward_agent = 0;
+	}
+}
+
+static int
+ssh_session(void)
+{
+	int type;
+	int interactive = 0;
+	int have_tty = 0;
+	struct winsize ws;
+	char *cp;
+	const char *display;
+
+	/* Enable compression if requested. */
+	if (options.compression) {
+		debug("Requesting compression at level %d.",
+		    options.compression_level);
+
+		if (options.compression_level < 1 ||
+		    options.compression_level > 9)
+			fatal("Compression level must be from 1 (fast) to "
+			    "9 (slow, best).");
+
+		/* Send the request. */
+		packet_start(SSH_CMSG_REQUEST_COMPRESSION);
+		packet_put_int(options.compression_level);
+		packet_send();
+		packet_write_wait();
+		type = packet_read();
+		if (type == SSH_SMSG_SUCCESS)
+			packet_start_compression(options.compression_level);
+		else if (type == SSH_SMSG_FAILURE)
+			logit("Warning: Remote host refused compression.");
+		else
+			packet_disconnect("Protocol error waiting for "
+			    "compression response.");
+	}
+	/* Allocate a pseudo tty if appropriate. */
+	if (tty_flag) {
+		debug("Requesting pty.");
+
+		/* Start the packet. */
+		packet_start(SSH_CMSG_REQUEST_PTY);
+
+		/* Store TERM in the packet.  There is no limit on the
+		   length of the string. */
+		cp = getenv("TERM");
+		if (!cp)
+			cp = "";
+		packet_put_cstring(cp);
+
+		/* Store window size in the packet. */
+		if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
+			memset(&ws, 0, sizeof(ws));
+		packet_put_int((u_int)ws.ws_row);
+		packet_put_int((u_int)ws.ws_col);
+		packet_put_int((u_int)ws.ws_xpixel);
+		packet_put_int((u_int)ws.ws_ypixel);
+
+		/* Store tty modes in the packet. */
+		tty_make_modes(fileno(stdin), NULL);
+
+		/* Send the packet, and wait for it to leave. */
+		packet_send();
+		packet_write_wait();
+
+		/* Read response from the server. */
+		type = packet_read();
+		if (type == SSH_SMSG_SUCCESS) {
+			interactive = 1;
+			have_tty = 1;
+		} else if (type == SSH_SMSG_FAILURE)
+			logit("Warning: Remote host failed or refused to "
+			    "allocate a pseudo tty.");
+		else
+			packet_disconnect("Protocol error waiting for pty "
+			    "request response.");
+	}
+	/* Request X11 forwarding if enabled and DISPLAY is set. */
+	display = getenv("DISPLAY");
+	if (options.forward_x11 && display != NULL) {
+		char *proto, *data;
+		/* Get reasonable local authentication information. */
+		client_x11_get_proto(display, options.xauth_location,
+		    options.forward_x11_trusted, 
+		    options.forward_x11_timeout,
+		    &proto, &data);
+		/* Request forwarding with authentication spoofing. */
+		debug("Requesting X11 forwarding with authentication "
+		    "spoofing.");
+		x11_request_forwarding_with_spoofing(0, display, proto,
+		    data, 0);
+		/* Read response from the server. */
+		type = packet_read();
+		if (type == SSH_SMSG_SUCCESS) {
+			interactive = 1;
+		} else if (type == SSH_SMSG_FAILURE) {
+			logit("Warning: Remote host denied X11 forwarding.");
+		} else {
+			packet_disconnect("Protocol error waiting for X11 "
+			    "forwarding");
+		}
+	}
+	/* Tell the packet module whether this is an interactive session. */
+	packet_set_interactive(interactive,
+	    options.ip_qos_interactive, options.ip_qos_bulk);
+
+	/* Request authentication agent forwarding if appropriate. */
+	check_agent_present();
+
+	if (options.forward_agent) {
+		debug("Requesting authentication agent forwarding.");
+		auth_request_forwarding();
+
+		/* Read response from the server. */
+		type = packet_read();
+		packet_check_eom();
+		if (type != SSH_SMSG_SUCCESS)
+			logit("Warning: Remote host denied authentication agent forwarding.");
+	}
+
+	/* Initiate port forwardings. */
+	ssh_init_forwarding();
+
+	/* Execute a local command */
+	if (options.local_command != NULL &&
+	    options.permit_local_command)
+		ssh_local_cmd(options.local_command);
+
+	/*
+	 * If requested and we are not interested in replies to remote
+	 * forwarding requests, then let ssh continue in the background.
+	 */
+	if (fork_after_authentication_flag) {
+		if (options.exit_on_forward_failure &&
+		    options.num_remote_forwards > 0) {
+			debug("deferring postauth fork until remote forward "
+			    "confirmation received");
+		} else
+			fork_postauth();
+	}
+
+	/*
+	 * If a command was specified on the command line, execute the
+	 * command now. Otherwise request the server to start a shell.
+	 */
+	if (buffer_len(&command) > 0) {
+		int len = buffer_len(&command);
+		if (len > 900)
+			len = 900;
+		debug("Sending command: %.*s", len,
+		    (u_char *)buffer_ptr(&command));
+		packet_start(SSH_CMSG_EXEC_CMD);
+		packet_put_string(buffer_ptr(&command), buffer_len(&command));
+		packet_send();
+		packet_write_wait();
+	} else {
+		debug("Requesting shell.");
+		packet_start(SSH_CMSG_EXEC_SHELL);
+		packet_send();
+		packet_write_wait();
+	}
+
+	/* Enter the interactive session. */
+	return client_loop(have_tty, tty_flag ?
+	    options.escape_char : SSH_ESCAPECHAR_NONE, 0);
+}
+
+/* request pty/x11/agent/tcpfwd/shell for channel */
+static void
+ssh_session2_setup(int id, int success, void *arg)
+{
+	extern char **environ;
+	const char *display;
+	int interactive = tty_flag;
+
+	if (!success)
+		return; /* No need for error message, channels code sens one */
+
+	display = getenv("DISPLAY");
+	if (options.forward_x11 && display != NULL) {
+		char *proto, *data;
+		/* Get reasonable local authentication information. */
+		client_x11_get_proto(display, options.xauth_location,
+		    options.forward_x11_trusted,
+		    options.forward_x11_timeout, &proto, &data);
+		/* Request forwarding with authentication spoofing. */
+		debug("Requesting X11 forwarding with authentication "
+		    "spoofing.");
+		x11_request_forwarding_with_spoofing(id, display, proto,
+		    data, 1);
+		client_expect_confirm(id, "X11 forwarding", CONFIRM_WARN);
+		/* XXX exit_on_forward_failure */
+		interactive = 1;
+	}
+
+	check_agent_present();
+	if (options.forward_agent) {
+		debug("Requesting authentication agent forwarding.");
+		channel_request_start(id, "auth-agent-req@openssh.com", 0);
+		packet_send();
+	}
+
+	client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"),
+	    NULL, fileno(stdin), &command, environ);
+}
+
+/* open new channel for a session */
+static int
+ssh_session2_open(void)
+{
+	Channel *c;
+	int window, packetmax, in, out, err;
+
+	if (stdin_null_flag) {
+		in = open(_PATH_DEVNULL, O_RDONLY);
+	} else {
+		in = dup(STDIN_FILENO);
+	}
+	out = dup(STDOUT_FILENO);
+	err = dup(STDERR_FILENO);
+
+	if (in < 0 || out < 0 || err < 0)
+		fatal("dup() in/out/err failed");
+
+	/* enable nonblocking unless tty */
+	if (!isatty(in))
+		set_nonblock(in);
+	if (!isatty(out))
+		set_nonblock(out);
+	if (!isatty(err))
+		set_nonblock(err);
+
+	window = CHAN_SES_WINDOW_DEFAULT;
+	packetmax = CHAN_SES_PACKET_DEFAULT;
+	if (tty_flag) {
+		window >>= 1;
+		packetmax >>= 1;
+	}
+	c = channel_new(
+	    "session", SSH_CHANNEL_OPENING, in, out, err,
+	    window, packetmax, CHAN_EXTENDED_WRITE,
+	    "client-session", /*nonblock*/0);
+
+	debug3("ssh_session2_open: channel_new: %d", c->self);
+
+	channel_send_open(c->self);
+	if (!no_shell_flag)
+		channel_register_open_confirm(c->self,
+		    ssh_session2_setup, NULL);
+
+	return c->self;
+}
+
+static int
+ssh_session2(void)
+{
+	int id = -1;
+
+	/* XXX should be pre-session */
+	ssh_init_forwarding();
+
+	/* Start listening for multiplex clients */
+	muxserver_listen();
+
+ 	/*
+	 * If we are in control persist mode, then prepare to background
+	 * ourselves and have a foreground client attach as a control
+	 * slave. NB. we must save copies of the flags that we override for
+	 * the backgrounding, since we defer attachment of the slave until
+	 * after the connection is fully established (in particular,
+	 * async rfwd replies have been received for ExitOnForwardFailure).
+	 */
+ 	if (options.control_persist && muxserver_sock != -1) {
+		ostdin_null_flag = stdin_null_flag;
+		ono_shell_flag = no_shell_flag;
+		orequest_tty = options.request_tty;
+		otty_flag = tty_flag;
+ 		stdin_null_flag = 1;
+ 		no_shell_flag = 1;
+ 		tty_flag = 0;
+		if (!fork_after_authentication_flag)
+			need_controlpersist_detach = 1;
+		fork_after_authentication_flag = 1;
+ 	}
+
+	if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN))
+		id = ssh_session2_open();
+
+	/* If we don't expect to open a new session, then disallow it */
+	if (options.control_master == SSHCTL_MASTER_NO &&
+	    (datafellows & SSH_NEW_OPENSSH)) {
+		debug("Requesting no-more-sessions@openssh.com");
+		packet_start(SSH2_MSG_GLOBAL_REQUEST);
+		packet_put_cstring("no-more-sessions@openssh.com");
+		packet_put_char(0);
+		packet_send();
+	}
+
+	/* Execute a local command */
+	if (options.local_command != NULL &&
+	    options.permit_local_command)
+		ssh_local_cmd(options.local_command);
+
+	/*
+	 * If requested and we are not interested in replies to remote
+	 * forwarding requests, then let ssh continue in the background.
+	 */
+	if (fork_after_authentication_flag) {
+		if (options.exit_on_forward_failure &&
+		    options.num_remote_forwards > 0) {
+			debug("deferring postauth fork until remote forward "
+			    "confirmation received");
+		} else
+			fork_postauth();
+	}
+
+	if (options.use_roaming)
+		request_roaming();
+
+	return client_loop(tty_flag, tty_flag ?
+	    options.escape_char : SSH_ESCAPECHAR_NONE, id);
+}
+
+static void
+load_public_identity_files(void)
+{
+	char *filename, *cp, thishost[NI_MAXHOST];
+	char *pwdir = NULL, *pwname = NULL;
+	int i = 0;
+	Key *public;
+	struct passwd *pw;
+	u_int n_ids;
+	char *identity_files[SSH_MAX_IDENTITY_FILES];
+	Key *identity_keys[SSH_MAX_IDENTITY_FILES];
+#ifdef ENABLE_PKCS11
+	Key **keys;
+	int nkeys;
+#endif /* PKCS11 */
+
+	n_ids = 0;
+	bzero(identity_files, sizeof(identity_files));
+	bzero(identity_keys, sizeof(identity_keys));
+
+#ifdef ENABLE_PKCS11
+	if (options.pkcs11_provider != NULL &&
+	    options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
+	    (pkcs11_init(!options.batch_mode) == 0) &&
+	    (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL,
+	    &keys)) > 0) {
+		for (i = 0; i < nkeys; i++) {
+			if (n_ids >= SSH_MAX_IDENTITY_FILES) {
+				key_free(keys[i]);
+				continue;
+			}
+			identity_keys[n_ids] = keys[i];
+			identity_files[n_ids] =
+			    xstrdup(options.pkcs11_provider); /* XXX */
+			n_ids++;
+		}
+		xfree(keys);
+	}
+#endif /* ENABLE_PKCS11 */
+	if ((pw = getpwuid(original_real_uid)) == NULL)
+		fatal("load_public_identity_files: getpwuid failed");
+	pwname = xstrdup(pw->pw_name);
+	pwdir = xstrdup(pw->pw_dir);
+	if (gethostname(thishost, sizeof(thishost)) == -1)
+		fatal("load_public_identity_files: gethostname: %s",
+		    strerror(errno));
+	for (i = 0; i < options.num_identity_files; i++) {
+		if (n_ids >= SSH_MAX_IDENTITY_FILES) {
+			xfree(options.identity_files[i]);
+			continue;
+		}
+		cp = tilde_expand_filename(options.identity_files[i],
+		    original_real_uid);
+		filename = percent_expand(cp, "d", pwdir,
+		    "u", pwname, "l", thishost, "h", host,
+		    "r", options.user, (char *)NULL);
+		xfree(cp);
+		public = key_load_public(filename, NULL);
+		debug("identity file %s type %d", filename,
+		    public ? public->type : -1);
+		xfree(options.identity_files[i]);
+		identity_files[n_ids] = filename;
+		identity_keys[n_ids] = public;
+
+		if (++n_ids >= SSH_MAX_IDENTITY_FILES)
+			continue;
+
+		/* Try to add the certificate variant too */
+		xasprintf(&cp, "%s-cert", filename);
+		public = key_load_public(cp, NULL);
+		debug("identity file %s type %d", cp,
+		    public ? public->type : -1);
+		if (public == NULL) {
+			xfree(cp);
+			continue;
+		}
+		if (!key_is_cert(public)) {
+			debug("%s: key %s type %s is not a certificate",
+			    __func__, cp, key_type(public));
+			key_free(public);
+			xfree(cp);
+			continue;
+		}
+		identity_keys[n_ids] = public;
+		/* point to the original path, most likely the private key */
+		identity_files[n_ids] = xstrdup(filename);
+		n_ids++;
+	}
+	options.num_identity_files = n_ids;
+	memcpy(options.identity_files, identity_files, sizeof(identity_files));
+	memcpy(options.identity_keys, identity_keys, sizeof(identity_keys));
+
+	bzero(pwname, strlen(pwname));
+	xfree(pwname);
+	bzero(pwdir, strlen(pwdir));
+	xfree(pwdir);
+}
+
+static void
+main_sigchld_handler(int sig)
+{
+	int save_errno = errno;
+	pid_t pid;
+	int status;
+
+	while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
+	    (pid < 0 && errno == EINTR))
+		;
+
+	signal(sig, main_sigchld_handler);
+	errno = save_errno;
+}
+