/* $OpenBSD: ssh.c,v 1.420 2015/07/30 00:01:34 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/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 <limits.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#ifdef WITH_OPENSSL
#include <openssl/evp.h>
#include <openssl/err.h>
#endif
#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 "digest.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 "misc.h"
#include "readconf.h"
#include "sshconnect.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"
#include "ssherr.h"
#include "myproposal.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 [-1246AaCfGgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec]\n"
" [-D [bind_address:]port] [-E log_file] [-e escape_char]\n"
" [-F configfile] [-I pkcs11] [-i identity_file]\n"
" [-L address] [-l login_name] [-m mac_spec]\n"
" [-O ctl_cmd] [-o option] [-p port]\n"
" [-Q cipher | cipher-auth | mac | kex | key]\n"
" [-R address] [-S ctl_path] [-W host:port]\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 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);
free(paths[i]);
paths[i] = cp;
}
}
/*
* Attempt to resolve a host name / port to a set of addresses and
* optionally return any CNAMEs encountered along the way.
* Returns NULL on failure.
* NB. this function must operate with a options having undefined members.
*/
static struct addrinfo *
resolve_host(const char *name, int port, int logerr, char *cname, size_t clen)
{
char strport[NI_MAXSERV];
struct addrinfo hints, *res;
int gaierr, loglevel = SYSLOG_LEVEL_DEBUG1;
if (port <= 0)
port = default_ssh_port();
snprintf(strport, sizeof strport, "%u", port);
memset(&hints, 0, sizeof(hints));
hints.ai_family = options.address_family == -1 ?
AF_UNSPEC : options.address_family;
hints.ai_socktype = SOCK_STREAM;
if (cname != NULL)
hints.ai_flags = AI_CANONNAME;
if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
if (logerr || (gaierr != EAI_NONAME && gaierr != EAI_NODATA))
loglevel = SYSLOG_LEVEL_ERROR;
do_log2(loglevel, "%s: Could not resolve hostname %.100s: %s",
__progname, name, ssh_gai_strerror(gaierr));
return NULL;
}
if (cname != NULL && res->ai_canonname != NULL) {
if (strlcpy(cname, res->ai_canonname, clen) >= clen) {
error("%s: host \"%s\" cname \"%s\" too long (max %lu)",
__func__, name, res->ai_canonname, (u_long)clen);
if (clen > 0)
*cname = '\0';
}
}
return res;
}
/*
* Attempt to resolve a numeric host address / port to a single address.
* Returns a canonical address string.
* Returns NULL on failure.
* NB. this function must operate with a options having undefined members.
*/
static struct addrinfo *
resolve_addr(const char *name, int port, char *caddr, size_t clen)
{
char addr[NI_MAXHOST], strport[NI_MAXSERV];
struct addrinfo hints, *res;
int gaierr;
if (port <= 0)
port = default_ssh_port();
snprintf(strport, sizeof strport, "%u", port);
memset(&hints, 0, sizeof(hints));
hints.ai_family = options.address_family == -1 ?
AF_UNSPEC : options.address_family;
hints.ai_socktype = SOCK_STREAM;
hints.ai_flags = AI_NUMERICHOST|AI_NUMERICSERV;
if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
debug2("%s: could not resolve name %.100s as address: %s",
__func__, name, ssh_gai_strerror(gaierr));
return NULL;
}
if (res == NULL) {
debug("%s: getaddrinfo %.100s returned no addresses",
__func__, name);
return NULL;
}
if (res->ai_next != NULL) {
debug("%s: getaddrinfo %.100s returned multiple addresses",
__func__, name);
goto fail;
}
if ((gaierr = getnameinfo(res->ai_addr, res->ai_addrlen,
addr, sizeof(addr), NULL, 0, NI_NUMERICHOST)) != 0) {
debug("%s: Could not format address for name %.100s: %s",
__func__, name, ssh_gai_strerror(gaierr));
goto fail;
}
if (strlcpy(caddr, addr, clen) >= clen) {
error("%s: host \"%s\" addr \"%s\" too long (max %lu)",
__func__, name, addr, (u_long)clen);
if (clen > 0)
*caddr = '\0';
fail:
freeaddrinfo(res);
return NULL;
}
return res;
}
/*
* Check whether the cname is a permitted replacement for the hostname
* and perform the replacement if it is.
* NB. this function must operate with a options having undefined members.
*/
static int
check_follow_cname(char **namep, const char *cname)
{
int i;
struct allowed_cname *rule;
if (*cname == '\0' || options.num_permitted_cnames == 0 ||
strcmp(*namep, cname) == 0)
return 0;
if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
return 0;
/*
* Don't attempt to canonicalize names that will be interpreted by
* a proxy unless the user specifically requests so.
*/
if (!option_clear_or_none(options.proxy_command) &&
options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
return 0;
debug3("%s: check \"%s\" CNAME \"%s\"", __func__, *namep, cname);
for (i = 0; i < options.num_permitted_cnames; i++) {
rule = options.permitted_cnames + i;
if (match_pattern_list(*namep, rule->source_list, 1) != 1 ||
match_pattern_list(cname, rule->target_list, 1) != 1)
continue;
verbose("Canonicalized DNS aliased hostname "
"\"%s\" => \"%s\"", *namep, cname);
free(*namep);
*namep = xstrdup(cname);
return 1;
}
return 0;
}
/*
* Attempt to resolve the supplied hostname after applying the user's
* canonicalization rules. Returns the address list for the host or NULL
* if no name was found after canonicalization.
* NB. this function must operate with a options having undefined members.
*/
static struct addrinfo *
resolve_canonicalize(char **hostp, int port)
{
int i, ndots;
char *cp, *fullhost, newname[NI_MAXHOST];
struct addrinfo *addrs;
if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
return NULL;
/*
* Don't attempt to canonicalize names that will be interpreted by
* a proxy unless the user specifically requests so.
*/
if (!option_clear_or_none(options.proxy_command) &&
options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
return NULL;
/* Try numeric hostnames first */
if ((addrs = resolve_addr(*hostp, port,
newname, sizeof(newname))) != NULL) {
debug2("%s: hostname %.100s is address", __func__, *hostp);
if (strcasecmp(*hostp, newname) != 0) {
debug2("%s: canonicalised address \"%s\" => \"%s\"",
__func__, *hostp, newname);
free(*hostp);
*hostp = xstrdup(newname);
}
return addrs;
}
/* Don't apply canonicalization to sufficiently-qualified hostnames */
ndots = 0;
for (cp = *hostp; *cp != '\0'; cp++) {
if (*cp == '.')
ndots++;
}
if (ndots > options.canonicalize_max_dots) {
debug3("%s: not canonicalizing hostname \"%s\" (max dots %d)",
__func__, *hostp, options.canonicalize_max_dots);
return NULL;
}
/* Attempt each supplied suffix */
for (i = 0; i < options.num_canonical_domains; i++) {
*newname = '\0';
xasprintf(&fullhost, "%s.%s.", *hostp,
options.canonical_domains[i]);
debug3("%s: attempting \"%s\" => \"%s\"", __func__,
*hostp, fullhost);
if ((addrs = resolve_host(fullhost, port, 0,
newname, sizeof(newname))) == NULL) {
free(fullhost);
continue;
}
/* Remove trailing '.' */
fullhost[strlen(fullhost) - 1] = '\0';
/* Follow CNAME if requested */
if (!check_follow_cname(&fullhost, newname)) {
debug("Canonicalized hostname \"%s\" => \"%s\"",
*hostp, fullhost);
}
free(*hostp);
*hostp = fullhost;
return addrs;
}
if (!options.canonicalize_fallback_local)
fatal("%s: Could not resolve host \"%s\"", __progname, *hostp);
debug2("%s: host %s not found in any suffix", __func__, *hostp);
return NULL;
}
/*
* Read per-user configuration file. Ignore the system wide config
* file if the user specifies a config file on the command line.
*/
static void
process_config_files(const char *host_arg, struct passwd *pw, int post_canon)
{
char buf[PATH_MAX];
int r;
if (config != NULL) {
if (strcasecmp(config, "none") != 0 &&
!read_config_file(config, pw, host, host_arg, &options,
SSHCONF_USERCONF | (post_canon ? SSHCONF_POSTCANON : 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, pw, host, host_arg,
&options, SSHCONF_CHECKPERM | SSHCONF_USERCONF |
(post_canon ? SSHCONF_POSTCANON : 0));
/* Read systemwide configuration file after user config. */
(void)read_config_file(_PATH_HOST_CONFIG_FILE, pw,
host, host_arg, &options,
post_canon ? SSHCONF_POSTCANON : 0);
}
}
/* Rewrite the port number in an addrinfo list of addresses */
static void
set_addrinfo_port(struct addrinfo *addrs, int port)
{
struct addrinfo *addr;
for (addr = addrs; addr != NULL; addr = addr->ai_next) {
switch (addr->ai_family) {
case AF_INET:
((struct sockaddr_in *)addr->ai_addr)->
sin_port = htons(port);
break;
case AF_INET6:
((struct sockaddr_in6 *)addr->ai_addr)->
sin6_port = htons(port);
break;
}
}
}
/*
* Main program for the ssh client.
*/
int
main(int ac, char **av)
{
int i, r, opt, exit_status, use_syslog, config_test = 0;
char *p, *cp, *line, *argv0, buf[PATH_MAX], *host_arg, *logfile;
char thishost[NI_MAXHOST], shorthost[NI_MAXHOST], portstr[NI_MAXSERV];
char cname[NI_MAXHOST];
struct stat st;
struct passwd *pw;
int timeout_ms;
extern int optind, optreset;
extern char *optarg;
struct Forward fwd;
struct addrinfo *addrs = NULL;
struct ssh_digest_ctx *md;
u_char conn_hash[SSH_DIGEST_MAX_LENGTH];
char *conn_hash_hex;
/* 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("No user exists for uid %lu", (u_long)original_real_uid);
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;
logfile = NULL;
argv0 = av[0];
again:
while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
"ACD:E:F:GI:KL:MNO:PQ:R: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 'E':
logfile = xstrdup(optarg);
break;
case 'G':
config_test = 1;
break;
case 'Y':
options.forward_x11 = 1;
options.forward_x11_trusted = 1;
break;
case 'g':
options.fwd_opts.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 if (strcmp(optarg, "cancel") == 0)
muxclient_command = SSHMUX_COMMAND_CANCEL_FWD;
else
fatal("Invalid multiplex command.");
break;
case 'P': /* deprecated */
options.use_privileged_port = 0;
break;
case 'Q':
cp = NULL;
if (strcmp(optarg, "cipher") == 0)
cp = cipher_alg_list('\n', 0);
else if (strcmp(optarg, "cipher-auth") == 0)
cp = cipher_alg_list('\n', 1);
else if (strcmp(optarg, "mac") == 0)
cp = mac_alg_list('\n');
else if (strcmp(optarg, "kex") == 0)
cp = kex_alg_list('\n');
else if (strcmp(optarg, "key") == 0)
cp = key_alg_list(0, 0);
else if (strcmp(optarg, "key-cert") == 0)
cp = key_alg_list(1, 0);
else if (strcmp(optarg, "key-plain") == 0)
cp = key_alg_list(0, 1);
else if (strcmp(optarg, "protocol-version") == 0) {
#ifdef WITH_SSH1
cp = xstrdup("1\n2");
#else
cp = xstrdup("2");
#endif
}
if (cp == NULL)
fatal("Unsupported query \"%s\"", optarg);
printf("%s\n", cp);
free(cp);
exit(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;
}
add_identity_file(&options, NULL, optarg, 1);
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;
case 'V':
fprintf(stderr, "%s, %s\n",
SSH_RELEASE,
#ifdef WITH_OPENSSL
SSLeay_version(SSLEAY_VERSION)
#else
"without OpenSSL"
#endif
);
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;
free(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 == '+' ?
optarg + 1 : optarg)) {
/* SSH2 only */
options.ciphers = xstrdup(optarg);
options.cipher = SSH_CIPHER_INVALID;
break;
}
/* 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 = xstrdup("3des-cbc");
else if (options.cipher == SSH_CIPHER_BLOWFISH)
options.ciphers = xstrdup("blowfish-cbc");
else
options.ciphers = xstrdup(KEX_CLIENT_ENCRYPT);
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':
line = xstrdup(optarg);
if (process_config_line(&options, pw,
host ? host : "", host ? host : "", line,
"command-line", 0, NULL, SSHCONF_USERCONF) != 0)
exit(255);
free(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 = xstrdup(++cp);
} else
host = xstrdup(*av);
if (ac > 1) {
optind = optreset = 1;
goto again;
}
ac--, av++;
}
/* Check that we got a host name. */
if (!host)
usage();
host_arg = xstrdup(host);
#ifdef WITH_OPENSSL
OpenSSL_add_all_algorithms();
ERR_load_crypto_strings();
#endif
/* 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. */
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.");
/*
* Initialize "log" output. Since we are the client all output
* goes to stderr unless otherwise specified by -y or -E.
*/
if (use_syslog && logfile != NULL)
fatal("Can't specify both -y and -E");
if (logfile != NULL) {
log_redirect_stderr_to(logfile);
free(logfile);
}
log_init(argv0,
options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
SYSLOG_FACILITY_USER, !use_syslog);
if (debug_flag)
logit("%s, %s", SSH_RELEASE,
#ifdef WITH_OPENSSL
SSLeay_version(SSLEAY_VERSION)
#else
"without OpenSSL"
#endif
);
/* Parse the configuration files */
process_config_files(host_arg, pw, 0);
/* Hostname canonicalisation needs a few options filled. */
fill_default_options_for_canonicalization(&options);
/* If the user has replaced the hostname then take it into use now */
if (options.hostname != NULL) {
/* NB. Please keep in sync with readconf.c:match_cfg_line() */
cp = percent_expand(options.hostname,
"h", host, (char *)NULL);
free(host);
host = cp;
free(options.hostname);
options.hostname = xstrdup(host);
}
/* If canonicalization requested then try to apply it */
lowercase(host);
if (options.canonicalize_hostname != SSH_CANONICALISE_NO)
addrs = resolve_canonicalize(&host, options.port);
/*
* If CanonicalizePermittedCNAMEs have been specified but
* other canonicalization did not happen (by not being requested
* or by failing with fallback) then the hostname may still be changed
* as a result of CNAME following.
*
* Try to resolve the bare hostname name using the system resolver's
* usual search rules and then apply the CNAME follow rules.
*
* Skip the lookup if a ProxyCommand is being used unless the user
* has specifically requested canonicalisation for this case via
* CanonicalizeHostname=always
*/
if (addrs == NULL && options.num_permitted_cnames != 0 &&
(option_clear_or_none(options.proxy_command) ||
options.canonicalize_hostname == SSH_CANONICALISE_ALWAYS)) {
if ((addrs = resolve_host(host, options.port,
option_clear_or_none(options.proxy_command),
cname, sizeof(cname))) == NULL) {
/* Don't fatal proxied host names not in the DNS */
if (option_clear_or_none(options.proxy_command))
cleanup_exit(255); /* logged in resolve_host */
} else
check_follow_cname(&host, cname);
}
/*
* If canonicalisation is enabled then re-parse the configuration
* files as new stanzas may match.
*/
if (options.canonicalize_hostname != 0) {
debug("Re-reading configuration after hostname "
"canonicalisation");
free(options.hostname);
options.hostname = xstrdup(host);
process_config_files(host_arg, pw, 1);
/*
* Address resolution happens early with canonicalisation
* enabled and the port number may have changed since, so
* reset it in address list
*/
if (addrs != NULL && options.port > 0)
set_addrinfo_port(addrs, options.port);
}
/* Fill configuration defaults. */
fill_default_options(&options);
if (options.port == 0)
options.port = default_ssh_port();
channel_set_af(options.address_family);
/* Tidy and check options */
if (options.host_key_alias != NULL)
lowercase(options.host_key_alias);
if (options.proxy_command != NULL &&
strcmp(options.proxy_command, "-") == 0 &&
options.proxy_use_fdpass)
fatal("ProxyCommand=- and ProxyUseFDPass are incompatible");
if (options.control_persist &&
options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) {
debug("UpdateHostKeys=ask is incompatible with ControlPersist; "
"disabling");
options.update_hostkeys = 0;
}
#ifndef HAVE_CYGWIN
if (original_effective_uid != 0)
options.use_privileged_port = 0;
#endif
/* reinit */
log_init(argv0, options.log_level, SYSLOG_FACILITY_USER, !use_syslog);
if (options.request_tty == REQUEST_TTY_YES ||
options.request_tty == REQUEST_TTY_FORCE)
tty_flag = 1;
/* 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;
}
seed_rng();
if (options.user == NULL)
options.user = xstrdup(pw->pw_name);
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 ((md = ssh_digest_start(SSH_DIGEST_SHA1)) == NULL ||
ssh_digest_update(md, thishost, strlen(thishost)) < 0 ||
ssh_digest_update(md, host, strlen(host)) < 0 ||
ssh_digest_update(md, portstr, strlen(portstr)) < 0 ||
ssh_digest_update(md, options.user, strlen(options.user)) < 0 ||
ssh_digest_final(md, conn_hash, sizeof(conn_hash)) < 0)
fatal("%s: mux digest failed", __func__);
ssh_digest_free(md);
conn_hash_hex = tohex(conn_hash, ssh_digest_bytes(SSH_DIGEST_SHA1));
if (options.local_command != NULL) {
debug3("expanding LocalCommand: %s", options.local_command);
cp = options.local_command;
options.local_command = percent_expand(cp,
"C", conn_hash_hex,
"L", shorthost,
"d", pw->pw_dir,
"h", host,
"l", thishost,
"n", host_arg,
"p", portstr,
"r", options.user,
"u", pw->pw_name,
(char *)NULL);
debug3("expanded LocalCommand: %s", options.local_command);
free(cp);
}
if (options.control_path != NULL) {
cp = tilde_expand_filename(options.control_path,
original_real_uid);
free(options.control_path);
options.control_path = percent_expand(cp,
"C", conn_hash_hex,
"L", shorthost,
"h", host,
"l", thishost,
"n", host_arg,
"p", portstr,
"r", options.user,
"u", pw->pw_name,
(char *)NULL);
free(cp);
}
free(conn_hash_hex);
if (config_test) {
dump_client_config(&options, host);
exit(0);
}
if (muxclient_command != 0 && options.control_path == NULL)
fatal("No ControlPath specified for \"-O\" command");
if (options.control_path != NULL)
muxclient(options.control_path);
/*
* If hostname canonicalisation was not enabled, then we may not
* have yet resolved the hostname. Do so now.
*/
if (addrs == NULL && options.proxy_command == NULL) {
if ((addrs = resolve_host(host, options.port, 1,
cname, sizeof(cname))) == NULL)
cleanup_exit(255); /* resolve_host logs the error */
}
timeout_ms = options.connection_timeout * 1000;
/* Open a connection to the remote host. */
if (ssh_connect(host, addrs, &hostaddr, options.port,
options.address_family, options.connection_attempts,
&timeout_ms, options.tcp_keep_alive,
options.use_privileged_port) != 0)
exit(255);
if (addrs != NULL)
freeaddrinfo(addrs);
packet_set_timeout(options.server_alive_interval,
options.server_alive_count_max);
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 = 9;
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);
#ifdef OPENSSL_HAS_ECC
sensitive_data.keys[1] = key_load_private_cert(KEY_ECDSA,
_PATH_HOST_ECDSA_KEY_FILE, "", NULL);
#endif
sensitive_data.keys[2] = key_load_private_cert(KEY_ED25519,
_PATH_HOST_ED25519_KEY_FILE, "", NULL);
sensitive_data.keys[3] = key_load_private_cert(KEY_RSA,
_PATH_HOST_RSA_KEY_FILE, "", NULL);
sensitive_data.keys[4] = key_load_private_cert(KEY_DSA,
_PATH_HOST_DSA_KEY_FILE, "", 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_ED25519,
_PATH_HOST_ED25519_KEY_FILE, "", NULL, NULL);
sensitive_data.keys[7] = key_load_private_type(KEY_RSA,
_PATH_HOST_RSA_KEY_FILE, "", NULL, NULL);
sensitive_data.keys[8] = key_load_private_type(KEY_DSA,
_PATH_HOST_DSA_KEY_FILE, "", NULL, NULL);
PRIV_END;
if (options.hostbased_authentication == 1 &&
sensitive_data.keys[0] == NULL &&
sensitive_data.keys[5] == NULL &&
sensitive_data.keys[6] == NULL &&
sensitive_data.keys[7] == NULL &&
sensitive_data.keys[8] == NULL) {
#ifdef OPENSSL_HAS_ECC
sensitive_data.keys[1] = key_load_cert(
_PATH_HOST_ECDSA_KEY_FILE);
#endif
sensitive_data.keys[2] = key_load_cert(
_PATH_HOST_ED25519_KEY_FILE);
sensitive_data.keys[3] = key_load_cert(
_PATH_HOST_RSA_KEY_FILE);
sensitive_data.keys[4] = key_load_cert(
_PATH_HOST_DSA_KEY_FILE);
#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_ED25519_KEY_FILE, NULL);
sensitive_data.keys[7] = key_load_public(
_PATH_HOST_RSA_KEY_FILE, NULL);
sensitive_data.keys[8] = key_load_public(
_PATH_HOST_DSA_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.
*/
if (config == NULL) {
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;
}
}
free(sensitive_data.keys);
}
for (i = 0; i < options.num_identity_files; i++) {
free(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);
}
daemon(1, 1);
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)
{
struct Forward *rfwd = (struct Forward *)ctxt;
/* XXX verbose() on failure? */
debug("remote forward %s for: listen %s%s%d, connect %s:%d",
type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
rfwd->listen_path ? rfwd->listen_path :
rfwd->listen_host ? rfwd->listen_host : "",
(rfwd->listen_path || rfwd->listen_host) ? ":" : "",
rfwd->listen_port, rfwd->connect_path ? rfwd->connect_path :
rfwd->connect_host, rfwd->connect_port);
if (rfwd->listen_path == NULL && rfwd->listen_port == 0) {
if (type == SSH2_MSG_REQUEST_SUCCESS) {
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);
channel_update_permitted_opens(rfwd->handle,
rfwd->allocated_port);
} else {
channel_update_permitted_opens(rfwd->handle, -1);
}
}
if (type == SSH2_MSG_REQUEST_FAILURE) {
if (options.exit_on_forward_failure) {
if (rfwd->listen_path != NULL)
fatal("Error: remote port forwarding failed "
"for listen path %s", rfwd->listen_path);
else
fatal("Error: remote port forwarding failed "
"for listen port %d", rfwd->listen_port);
} else {
if (rfwd->listen_path != NULL)
logit("Warning: remote port forwarding failed "
"for listen path %s", rfwd->listen_path);
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 void
ssh_stdio_confirm(int id, int success, void *arg)
{
if (!success)
fatal("stdio forwarding failed");
}
static void
ssh_init_stdio_forwarding(void)
{
Channel *c;
int in, out;
if (stdio_forward_host == NULL)
return;
if (!compat20)
fatal("stdio forwarding require Protocol 2");
debug3("%s: %s:%d", __func__, stdio_forward_host, stdio_forward_port);
if ((in = dup(STDIN_FILENO)) < 0 ||
(out = dup(STDOUT_FILENO)) < 0)
fatal("channel_connect_stdio_fwd: dup() in/out failed");
if ((c = channel_connect_stdio_fwd(stdio_forward_host,
stdio_forward_port, in, out)) == NULL)
fatal("%s: channel_connect_stdio_fwd failed", __func__);
channel_register_cleanup(c->self, client_cleanup_stdio_fwd, 0);
channel_register_open_confirm(c->self, ssh_stdio_confirm, NULL);
}
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_path != NULL) ?
options.local_forwards[i].listen_path :
(options.local_forwards[i].listen_host == NULL) ?
(options.fwd_opts.gateway_ports ? "*" : "LOCALHOST") :
options.local_forwards[i].listen_host,
options.local_forwards[i].listen_port,
(options.local_forwards[i].connect_path != NULL) ?
options.local_forwards[i].connect_path :
options.local_forwards[i].connect_host,
options.local_forwards[i].connect_port);
success += channel_setup_local_fwd_listener(
&options.local_forwards[i], &options.fwd_opts);
}
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_path != NULL) ?
options.remote_forwards[i].listen_path :
(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_path != NULL) ?
options.remote_forwards[i].connect_path :
options.remote_forwards[i].connect_host,
options.remote_forwards[i].connect_port);
options.remote_forwards[i].handle =
channel_request_remote_forwarding(
&options.remote_forwards[i]);
if (options.remote_forwards[i].handle < 0) {
if (options.exit_on_forward_failure)
fatal("Could not request remote forwarding.");
else
logit("Warning: Could not request remote "
"forwarding.");
} else {
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)
{
int r;
if (options.forward_agent) {
/* Clear agent forwarding if we don't have an agent. */
if ((r = ssh_get_authentication_socket(NULL)) != 0) {
options.forward_agent = 0;
if (r != SSH_ERR_AGENT_NOT_PRESENT)
debug("ssh_get_authentication_socket: %s",
ssh_err(r));
}
}
}
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 (display == NULL && options.forward_x11)
debug("X11 forwarding requested but DISPLAY not set");
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_stdio_forwarding();
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 (display == NULL && options.forward_x11)
debug("X11 forwarding requested but DISPLAY not set");
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();
}
/* Tell the packet module whether this is an interactive session. */
packet_set_interactive(interactive,
options.ip_qos_interactive, options.ip_qos_bulk);
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 */
if (!options.control_persist)
ssh_init_stdio_forwarding();
ssh_init_forwarding();
/* Start listening for multiplex clients */
muxserver_listen();
/*
* If we are in control persist mode and have a working mux listen
* socket, 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;
}
/*
* ControlPersist mux listen socket setup failed, attempt the
* stdio forward setup that we skipped earlier.
*/
if (options.control_persist && muxserver_sock == -1)
ssh_init_stdio_forwarding();
if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN))
id = ssh_session2_open();
else {
packet_set_interactive(
options.control_master == SSHCTL_MASTER_NO,
options.ip_qos_interactive, options.ip_qos_bulk);
}
/* 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();
}
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;
memset(identity_files, 0, sizeof(identity_files));
memset(identity_keys, 0, 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++;
}
free(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 ||
strcasecmp(options.identity_files[i], "none") == 0) {
free(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);
free(cp);
public = key_load_public(filename, NULL);
debug("identity file %s type %d", filename,
public ? public->type : -1);
free(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) {
free(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);
free(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));
explicit_bzero(pwname, strlen(pwname));
free(pwname);
explicit_bzero(pwdir, strlen(pwdir));
free(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;
}