/* $OpenBSD: ssh.c,v 1.301 2007/08/07 07:32:53 djm Exp $ */
/*
* Author: Tatu Ylonen <[email protected]>
* Copyright (c) 1995 Tatu Ylonen <[email protected]>, 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 <[email protected]>
* 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/time.h>
#include <sys/resource.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/un.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 "xmalloc.h"
#include "ssh.h"
#include "ssh1.h"
#include "ssh2.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 "monitor_fdpass.h"
#include "uidswap.h"
#include "version.h"
#ifdef SMARTCARD
#include "scard.h"
#endif
extern char *__progname;
/* Flag indicating whether debug mode is on. This can be set on the command line. */
int debug_flag = 0;
/* Flag indicating whether a tty should be allocated */
int tty_flag = 0;
int no_tty_flag = 0;
int force_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 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;
/*
* 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 client_global_request_id = 0;
/* pid of proxycommand child process */
pid_t proxy_command_pid = 0;
/* fd to control socket */
int control_fd = -1;
/* Multiplexing control command */
static u_int mux_command = 0;
/* Only used in control client mode */
volatile sig_atomic_t control_client_terminate = 0;
u_int control_server_pid = 0;
/* Prints a help message to the user. This function never returns. */
static void
usage(void)
{
fprintf(stderr,
"usage: ssh [-1246AaCfgKkMNnqsTtVvXxY] [-b bind_address] [-c cipher_spec]\n"
" [-D [bind_address:]port] [-e escape_char] [-F configfile]\n"
" [-i identity_file] [-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 local_tun[:remote_tun]] [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 control_client(const char *path);
/*
* Main program for the ssh client.
*/
int
main(int ac, char **av)
{
int i, opt, exit_status;
char *p, *cp, *line, buf[256];
struct stat st;
struct passwd *pw;
int dummy;
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]);
init_rng();
/*
* 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;
again:
while ((opt = getopt(ac, av,
"1246ab:c:e:fgi:kl:m:no:p:qstvxACD:F:I:KL:MNO:PR:S:TVw:XY")) != -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':
options.forward_x11 = 1;
options.forward_x11_trusted = 1;
break;
case 'g':
options.gateway_ports = 1;
break;
case 'O':
if (strcmp(optarg, "check") == 0)
mux_command = SSHMUX_COMMAND_ALIVE_CHECK;
else if (strcmp(optarg, "exit") == 0)
mux_command = SSHMUX_COMMAND_TERMINATE;
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 SMARTCARD
options.smartcard_device = xstrdup(optarg);
#else
fprintf(stderr, "no support for smartcards.\n");
#endif
break;
case 't':
if (tty_flag)
force_tty_flag = 1;
tty_flag = 1;
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 '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))
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)) {
add_remote_forward(&options, &fwd);
} else {
fprintf(stderr,
"Bad remote forwarding specification "
"'%s'\n", optarg);
exit(255);
}
break;
case 'D':
cp = p = xstrdup(optarg);
memset(&fwd, '\0', sizeof(fwd));
fwd.connect_host = "socks";
if ((fwd.listen_host = hpdelim(&cp)) == NULL) {
fprintf(stderr, "Bad dynamic forwarding "
"specification '%.100s'\n", optarg);
exit(255);
}
if (cp != NULL) {
fwd.listen_port = a2port(cp);
fwd.listen_host = cleanhostname(fwd.listen_host);
} else {
fwd.listen_port = a2port(fwd.listen_host);
fwd.listen_host = NULL;
}
if (fwd.listen_port == 0) {
fprintf(stderr, "Bad dynamic port '%s'\n",
optarg);
exit(255);
}
add_local_forward(&options, &fwd);
xfree(p);
break;
case 'C':
options.compression = 1;
break;
case 'N':
no_shell_flag = 1;
no_tty_flag = 1;
break;
case 'T':
no_tty_flag = 1;
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 && **av != '-') {
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();
SSLeay_add_all_algorithms();
ERR_load_crypto_strings();
/* Initialize the command to execute on remote host. */
buffer_init(&command);
/*
* 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 = 1;
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 = 1;
/* Force no tty */
if (no_tty_flag)
tty_flag = 0;
/* Do not allocate a tty if stdin is not a tty. */
if ((!isatty(fileno(stdin)) || stdin_null_flag) && !force_tty_flag) {
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(av[0], options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
SYSLOG_FACILITY_USER, 1);
/*
* 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 {
snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir,
_PATH_SSH_USER_CONFFILE);
(void)read_config_file(buf, host, &options, 1);
/* Read systemwide configuration file after use 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(av[0], options.log_level, SYSLOG_FACILITY_USER, 1);
seed_rng();
if (options.user == NULL)
options.user = xstrdup(pw->pw_name);
if (options.hostname != NULL)
host = options.hostname;
/* 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);
}
/* 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;
}
if (options.proxy_command != NULL &&
strcmp(options.proxy_command, "none") == 0)
options.proxy_command = NULL;
if (options.control_path != NULL &&
strcmp(options.control_path, "none") == 0)
options.control_path = NULL;
if (options.control_path != NULL) {
char thishost[NI_MAXHOST];
if (gethostname(thishost, sizeof(thishost)) == -1)
fatal("gethostname: %s", strerror(errno));
snprintf(buf, sizeof(buf), "%d", options.port);
cp = tilde_expand_filename(options.control_path,
original_real_uid);
options.control_path = percent_expand(cp, "p", buf, "h", host,
"r", options.user, "l", thishost, (char *)NULL);
xfree(cp);
}
if (mux_command != 0 && options.control_path == NULL)
fatal("No ControlPath specified for \"-O\" command");
if (options.control_path != NULL)
control_client(options.control_path);
/* Open a connection to the remote host. */
if (ssh_connect(host, &hostaddr, options.port,
options.address_family, options.connection_attempts,
#ifdef HAVE_CYGWIN
options.use_privileged_port,
#else
original_effective_uid == 0 && options.use_privileged_port,
#endif
options.proxy_command) != 0)
exit(255);
/*
* 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 = 3;
sensitive_data.keys = xcalloc(sensitive_data.nkeys,
sizeof(Key));
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_type(KEY_DSA,
_PATH_HOST_DSA_KEY_FILE, "", NULL, NULL);
sensitive_data.keys[2] = 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[1] == NULL &&
sensitive_data.keys[2] == NULL) {
sensitive_data.keys[1] = key_load_public(
_PATH_HOST_DSA_KEY_FILE, NULL);
sensitive_data.keys[2] = 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.
*/
snprintf(buf, sizeof buf, "%.100s%s%.100s", pw->pw_dir, strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR);
if (stat(buf, &st) < 0)
if (mkdir(buf, 0700) < 0)
error("Could not create directory '%.200s'.", buf);
/* load options.identity_files */
load_public_identity_files();
/* Expand ~ in known host file names. */
/* XXX mem-leaks: */
options.system_hostfile =
tilde_expand_filename(options.system_hostfile, original_real_uid);
options.user_hostfile =
tilde_expand_filename(options.user_hostfile, original_real_uid);
options.system_hostfile2 =
tilde_expand_filename(options.system_hostfile2, original_real_uid);
options.user_hostfile2 =
tilde_expand_filename(options.user_hostfile2, original_real_uid);
signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
/* Log into the remote system. This never returns if the login fails. */
ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr, pw);
/* 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 && control_fd != -1)
unlink(options.control_path);
/*
* Send SIGHUP to proxy command if used. We don't wait() in
* case it hangs and instead rely on init to reap the child
*/
if (proxy_command_pid > 1)
kill(proxy_command_pid, SIGHUP);
return exit_status;
}
static void
ssh_init_forwarding(void)
{
int success = 0;
int i;
/* 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.");
}
}
/* 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, &proto, &data);
/* Request forwarding with authentication spoofing. */
debug("Requesting X11 forwarding with authentication spoofing.");
x11_request_forwarding_with_spoofing(0, display, proto, data);
/* 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);
/* 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();
/* If requested, let ssh continue in the background. */
if (fork_after_authentication_flag)
if (daemon(1, 1) < 0)
fatal("daemon() failed: %.200s", strerror(errno));
/*
* 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);
}
static void
ssh_subsystem_reply(int type, u_int32_t seq, void *ctxt)
{
int id, len;
id = packet_get_int();
len = buffer_len(&command);
if (len > 900)
len = 900;
packet_check_eom();
if (type == SSH2_MSG_CHANNEL_FAILURE)
fatal("Request for subsystem '%.*s' failed on channel %d",
len, (u_char *)buffer_ptr(&command), id);
}
void
client_global_request_reply_fwd(int type, u_int32_t seq, void *ctxt)
{
int i;
i = client_global_request_id++;
if (i >= options.num_remote_forwards)
return;
debug("remote forward %s for: listen %d, connect %s:%d",
type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
options.remote_forwards[i].listen_port,
options.remote_forwards[i].connect_host,
options.remote_forwards[i].connect_port);
if (type == SSH2_MSG_REQUEST_FAILURE) {
if (options.exit_on_forward_failure)
fatal("Error: remote port forwarding failed for "
"listen port %d",
options.remote_forwards[i].listen_port);
else
logit("Warning: remote port forwarding failed for "
"listen port %d",
options.remote_forwards[i].listen_port);
}
}
static void
ssh_control_listener(void)
{
struct sockaddr_un addr;
mode_t old_umask;
int addr_len;
if (options.control_path == NULL ||
options.control_master == SSHCTL_MASTER_NO)
return;
debug("setting up multiplex master socket");
memset(&addr, '\0', sizeof(addr));
addr.sun_family = AF_UNIX;
addr_len = offsetof(struct sockaddr_un, sun_path) +
strlen(options.control_path) + 1;
if (strlcpy(addr.sun_path, options.control_path,
sizeof(addr.sun_path)) >= sizeof(addr.sun_path))
fatal("ControlPath too long");
if ((control_fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
fatal("%s socket(): %s", __func__, strerror(errno));
old_umask = umask(0177);
if (bind(control_fd, (struct sockaddr *)&addr, addr_len) == -1) {
control_fd = -1;
if (errno == EINVAL || errno == EADDRINUSE)
fatal("ControlSocket %s already exists",
options.control_path);
else
fatal("%s bind(): %s", __func__, strerror(errno));
}
umask(old_umask);
if (listen(control_fd, 64) == -1)
fatal("%s listen(): %s", __func__, strerror(errno));
set_nonblock(control_fd);
}
/* request pty/x11/agent/tcpfwd/shell for channel */
static void
ssh_session2_setup(int id, void *arg)
{
extern char **environ;
const char *display;
int interactive = tty_flag;
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, &proto, &data);
/* Request forwarding with authentication spoofing. */
debug("Requesting X11 forwarding with authentication spoofing.");
x11_request_forwarding_with_spoofing(id, display, proto, data);
interactive = 1;
/* XXX wait for reply */
}
check_agent_present();
if (options.forward_agent) {
debug("Requesting authentication agent forwarding.");
channel_request_start(id, "[email protected]", 0);
packet_send();
}
client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"),
NULL, fileno(stdin), &command, environ, &ssh_subsystem_reply);
packet_set_interactive(interactive);
}
/* 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_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();
if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN))
id = ssh_session2_open();
/* Execute a local command */
if (options.local_command != NULL &&
options.permit_local_command)
ssh_local_cmd(options.local_command);
/* Start listening for multiplex clients */
ssh_control_listener();
/* If requested, let ssh continue in the background. */
if (fork_after_authentication_flag)
if (daemon(1, 1) < 0)
fatal("daemon() failed: %.200s", strerror(errno));
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];
int i = 0;
Key *public;
struct passwd *pw;
#ifdef SMARTCARD
Key **keys;
if (options.smartcard_device != NULL &&
options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
(keys = sc_get_keys(options.smartcard_device, NULL)) != NULL) {
int count = 0;
for (i = 0; keys[i] != NULL; i++) {
count++;
memmove(&options.identity_files[1], &options.identity_files[0],
sizeof(char *) * (SSH_MAX_IDENTITY_FILES - 1));
memmove(&options.identity_keys[1], &options.identity_keys[0],
sizeof(Key *) * (SSH_MAX_IDENTITY_FILES - 1));
options.num_identity_files++;
options.identity_keys[0] = keys[i];
options.identity_files[0] = sc_get_key_label(keys[i]);
}
if (options.num_identity_files > SSH_MAX_IDENTITY_FILES)
options.num_identity_files = SSH_MAX_IDENTITY_FILES;
i = count;
xfree(keys);
}
#endif /* SMARTCARD */
if ((pw = getpwuid(original_real_uid)) == NULL)
fatal("load_public_identity_files: getpwuid failed");
if (gethostname(thishost, sizeof(thishost)) == -1)
fatal("load_public_identity_files: gethostname: %s",
strerror(errno));
for (; i < options.num_identity_files; i++) {
cp = tilde_expand_filename(options.identity_files[i],
original_real_uid);
filename = percent_expand(cp, "d", pw->pw_dir,
"u", pw->pw_name, "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]);
options.identity_files[i] = filename;
options.identity_keys[i] = public;
}
}
static void
control_client_sighandler(int signo)
{
control_client_terminate = signo;
}
static void
control_client_sigrelay(int signo)
{
if (control_server_pid > 1)
kill(control_server_pid, signo);
}
static int
env_permitted(char *env)
{
int i, ret;
char name[1024], *cp;
if ((cp = strchr(env, '=')) == NULL || cp == env)
return (0);
ret = snprintf(name, sizeof(name), "%.*s", (int)(cp - env), env);
if (ret <= 0 || (size_t)ret >= sizeof(name))
fatal("env_permitted: name '%.100s...' too long", env);
for (i = 0; i < options.num_send_env; i++)
if (match_pattern(name, options.send_env[i]))
return (1);
return (0);
}
static void
control_client(const char *path)
{
struct sockaddr_un addr;
int i, r, fd, sock, exitval[2], num_env, addr_len;
Buffer m;
char *term;
extern char **environ;
u_int flags;
if (mux_command == 0)
mux_command = SSHMUX_COMMAND_OPEN;
switch (options.control_master) {
case SSHCTL_MASTER_AUTO:
case SSHCTL_MASTER_AUTO_ASK:
debug("auto-mux: Trying existing master");
/* FALLTHROUGH */
case SSHCTL_MASTER_NO:
break;
default:
return;
}
memset(&addr, '\0', sizeof(addr));
addr.sun_family = AF_UNIX;
addr_len = offsetof(struct sockaddr_un, sun_path) +
strlen(path) + 1;
if (strlcpy(addr.sun_path, path,
sizeof(addr.sun_path)) >= sizeof(addr.sun_path))
fatal("ControlPath too long");
if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
fatal("%s socket(): %s", __func__, strerror(errno));
if (connect(sock, (struct sockaddr *)&addr, addr_len) == -1) {
if (mux_command != SSHMUX_COMMAND_OPEN) {
fatal("Control socket connect(%.100s): %s", path,
strerror(errno));
}
if (errno == ENOENT)
debug("Control socket \"%.100s\" does not exist", path);
else {
error("Control socket connect(%.100s): %s", path,
strerror(errno));
}
close(sock);
return;
}
if (stdin_null_flag) {
if ((fd = open(_PATH_DEVNULL, O_RDONLY)) == -1)
fatal("open(/dev/null): %s", strerror(errno));
if (dup2(fd, STDIN_FILENO) == -1)
fatal("dup2: %s", strerror(errno));
if (fd > STDERR_FILENO)
close(fd);
}
term = getenv("TERM");
flags = 0;
if (tty_flag)
flags |= SSHMUX_FLAG_TTY;
if (subsystem_flag)
flags |= SSHMUX_FLAG_SUBSYS;
if (options.forward_x11)
flags |= SSHMUX_FLAG_X11_FWD;
if (options.forward_agent)
flags |= SSHMUX_FLAG_AGENT_FWD;
buffer_init(&m);
/* Send our command to server */
buffer_put_int(&m, mux_command);
buffer_put_int(&m, flags);
if (ssh_msg_send(sock, SSHMUX_VER, &m) == -1)
fatal("%s: msg_send", __func__);
buffer_clear(&m);
/* Get authorisation status and PID of controlee */
if (ssh_msg_recv(sock, &m) == -1)
fatal("%s: msg_recv", __func__);
if (buffer_get_char(&m) != SSHMUX_VER)
fatal("%s: wrong version", __func__);
if (buffer_get_int(&m) != 1)
fatal("Connection to master denied");
control_server_pid = buffer_get_int(&m);
buffer_clear(&m);
switch (mux_command) {
case SSHMUX_COMMAND_ALIVE_CHECK:
fprintf(stderr, "Master running (pid=%d)\r\n",
control_server_pid);
exit(0);
case SSHMUX_COMMAND_TERMINATE:
fprintf(stderr, "Exit request sent.\r\n");
exit(0);
case SSHMUX_COMMAND_OPEN:
/* continue below */
break;
default:
fatal("silly mux_command %d", mux_command);
}
/* SSHMUX_COMMAND_OPEN */
buffer_put_cstring(&m, term ? term : "");
buffer_append(&command, "\0", 1);
buffer_put_cstring(&m, buffer_ptr(&command));
if (options.num_send_env == 0 || environ == NULL) {
buffer_put_int(&m, 0);
} else {
/* Pass environment */
num_env = 0;
for (i = 0; environ[i] != NULL; i++)
if (env_permitted(environ[i]))
num_env++; /* Count */
buffer_put_int(&m, num_env);
for (i = 0; environ[i] != NULL && num_env >= 0; i++)
if (env_permitted(environ[i])) {
num_env--;
buffer_put_cstring(&m, environ[i]);
}
}
if (ssh_msg_send(sock, SSHMUX_VER, &m) == -1)
fatal("%s: msg_send", __func__);
mm_send_fd(sock, STDIN_FILENO);
mm_send_fd(sock, STDOUT_FILENO);
mm_send_fd(sock, STDERR_FILENO);
/* Wait for reply, so master has a chance to gather ttymodes */
buffer_clear(&m);
if (ssh_msg_recv(sock, &m) == -1)
fatal("%s: msg_recv", __func__);
if (buffer_get_char(&m) != SSHMUX_VER)
fatal("%s: wrong version", __func__);
buffer_free(&m);
signal(SIGHUP, control_client_sighandler);
signal(SIGINT, control_client_sighandler);
signal(SIGTERM, control_client_sighandler);
#ifdef SIGWINCH
signal(SIGWINCH, control_client_sigrelay);
#endif
if (tty_flag)
enter_raw_mode();
/*
* Stick around until the controlee closes the client_fd.
* Before it does, it is expected to write this process' exit
* value (one int). This process must read the value and wait for
* the closure of the client_fd; if this one closes early, the
* multiplex master will terminate early too (possibly losing data).
*/
exitval[0] = 0;
for (i = 0; !control_client_terminate && i < (int)sizeof(exitval);) {
r = read(sock, (char *)exitval + i, sizeof(exitval) - i);
if (r == 0) {
debug2("Received EOF from master");
break;
}
if (r == -1) {
if (errno == EINTR)
continue;
fatal("%s: read %s", __func__, strerror(errno));
}
i += r;
}
close(sock);
leave_raw_mode();
if (i > (int)sizeof(int))
fatal("%s: master returned too much data (%d > %lu)",
__func__, i, sizeof(int));
if (control_client_terminate) {
debug2("Exiting on signal %d", control_client_terminate);
exitval[0] = 255;
} else if (i < (int)sizeof(int)) {
debug2("Control master terminated unexpectedly");
exitval[0] = 255;
} else
debug2("Received exit status from master %d", exitval[0]);
if (tty_flag && options.log_level != SYSLOG_LEVEL_QUIET)
fprintf(stderr, "Shared connection to %s closed.\r\n", host);
exit(exitval[0]);
}
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