RepoMirrors
/
openssh
mirror of git://anongit.mindrot.org/openssh.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity
openssh/ssh.c

1232 lines
35 KiB
C
Raw Blame History

/*
* 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"
RCSID("$OpenBSD: ssh.c,v 1.203 2003/11/21 11:57:03 djm Exp $");
#include <openssl/evp.h>
#include <openssl/err.h>
#include "ssh.h"
#include "ssh1.h"
#include "ssh2.h"
#include "compat.h"
#include "cipher.h"
#include "xmalloc.h"
#include "packet.h"
#include "buffer.h"
#include "channels.h"
#include "key.h"
#include "authfd.h"
#include "authfile.h"
#include "pathnames.h"
#include "clientloop.h"
#include "log.h"
#include "readconf.h"
#include "sshconnect.h"
#include "tildexpand.h"
#include "dispatch.h"
#include "misc.h"
#include "kex.h"
#include "mac.h"
#include "sshtty.h"
#ifdef SMARTCARD
#include "scard.h"
#endif
#ifdef HAVE___PROGNAME
extern char *__progname;
#else
char *__progname;
#endif
/* 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;
/* Prints a help message to the user. This function never returns. */
static void
usage(void)
{
fprintf(stderr, "Usage: %s [options] host [command]\n", __progname);
fprintf(stderr, "Options:\n");
fprintf(stderr, " -l user Log in using this user name.\n");
fprintf(stderr, " -n Redirect input from " _PATH_DEVNULL ".\n");
fprintf(stderr, " -F config Config file (default: ~/%s).\n",
_PATH_SSH_USER_CONFFILE);
fprintf(stderr, " -A Enable authentication agent forwarding.\n");
fprintf(stderr, " -a Disable authentication agent forwarding (default).\n");
fprintf(stderr, " -X Enable X11 connection forwarding.\n");
fprintf(stderr, " -Y Enable trusted X11 connection forwarding.\n");
fprintf(stderr, " -x Disable X11 connection forwarding (default).\n");
fprintf(stderr, " -i file Identity for public key authentication "
"(default: ~/.ssh/identity)\n");
#ifdef SMARTCARD
fprintf(stderr, " -I reader Set smartcard reader.\n");
#endif
fprintf(stderr, " -t Tty; allocate a tty even if command is given.\n");
fprintf(stderr, " -T Do not allocate a tty.\n");
fprintf(stderr, " -v Verbose; display verbose debugging messages.\n");
fprintf(stderr, " Multiple -v increases verbosity.\n");
fprintf(stderr, " -V Display version number only.\n");
fprintf(stderr, " -q Quiet; don't display any warning messages.\n");
fprintf(stderr, " -f Fork into background after authentication.\n");
fprintf(stderr, " -e char Set escape character; ``none'' = disable (default: ~).\n");
fprintf(stderr, " -c cipher Select encryption algorithm\n");
fprintf(stderr, " -m macs Specify MAC algorithms for protocol version 2.\n");
fprintf(stderr, " -p port Connect to this port. Server must be on the same port.\n");
fprintf(stderr, " -L listen-port:host:port Forward local port to remote address\n");
fprintf(stderr, " -R listen-port:host:port Forward remote port to local address\n");
fprintf(stderr, " These cause %s to listen for connections on a port, and\n", __progname);
fprintf(stderr, " forward them to the other side by connecting to host:port.\n");
fprintf(stderr, " -D port Enable dynamic application-level port forwarding.\n");
fprintf(stderr, " -C Enable compression.\n");
fprintf(stderr, " -N Do not execute a shell or command.\n");
fprintf(stderr, " -g Allow remote hosts to connect to forwarded ports.\n");
fprintf(stderr, " -1 Force protocol version 1.\n");
fprintf(stderr, " -2 Force protocol version 2.\n");
fprintf(stderr, " -4 Use IPv4 only.\n");
fprintf(stderr, " -6 Use IPv6 only.\n");
fprintf(stderr, " -o 'option' Process the option as if it was read from a configuration file.\n");
fprintf(stderr, " -s Invoke command (mandatory) as SSH2 subsystem.\n");
fprintf(stderr, " -b addr Local IP address.\n");
exit(1);
}
static int ssh_session(void);
static int ssh_session2(void);
static void load_public_identity_files(void);
/*
* Main program for the ssh client.
*/
int
main(int ac, char **av)
{
int i, opt, exit_status;
u_short fwd_port, fwd_host_port;
char sfwd_port[6], sfwd_host_port[6];
char *p, *cp, buf[256];
struct stat st;
struct passwd *pw;
int dummy;
extern int optind, optreset;
extern char *optarg;
__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(1);
}
/* 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:L:NPR:TVXY")) != -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 'P': /* deprecated */
options.use_privileged_port = 0;
break;
case 'a':
options.forward_agent = 0;
break;
case 'A':
options.forward_agent = 1;
break;
case 'k':
/* ignored for backward compatibility */
break;
case 'i':
if (stat(optarg, &st) < 0) {
fprintf(stderr, "Warning: Identity file %s "
"does not exist.\n", optarg);
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, SSH protocols %d.%d/%d.%d, %s\n",
SSH_VERSION,
PROTOCOL_MAJOR_1, PROTOCOL_MINOR_1,
PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2,
SSLeay_version(SSLEAY_VERSION));
if (opt == 'V')
exit(0);
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(1);
}
break;
case 'c':
if (ciphers_valid(optarg)) {
/* SSH2 only */
options.ciphers = xstrdup(optarg);
options.cipher = SSH_CIPHER_ILLEGAL;
} else {
/* SSH1 only */
options.cipher = cipher_number(optarg);
if (options.cipher == -1) {
fprintf(stderr,
"Unknown cipher type '%s'\n",
optarg);
exit(1);
}
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(1);
}
break;
case 'p':
options.port = a2port(optarg);
if (options.port == 0) {
fprintf(stderr, "Bad port '%s'\n", optarg);
exit(1);
}
break;
case 'l':
options.user = optarg;
break;
case 'L':
case 'R':
if (sscanf(optarg, "%5[0123456789]:%255[^:]:%5[0123456789]",
sfwd_port, buf, sfwd_host_port) != 3 &&
sscanf(optarg, "%5[0123456789]/%255[^/]/%5[0123456789]",
sfwd_port, buf, sfwd_host_port) != 3) {
fprintf(stderr,
"Bad forwarding specification '%s'\n",
optarg);
usage();
/* NOTREACHED */
}
if ((fwd_port = a2port(sfwd_port)) == 0 ||
(fwd_host_port = a2port(sfwd_host_port)) == 0) {
fprintf(stderr,
"Bad forwarding port(s) '%s'\n", optarg);
exit(1);
}
if (opt == 'L')
add_local_forward(&options, fwd_port, buf,
fwd_host_port);
else if (opt == 'R')
add_remote_forward(&options, fwd_port, buf,
fwd_host_port);
break;
case 'D':
fwd_port = a2port(optarg);
if (fwd_port == 0) {
fprintf(stderr, "Bad dynamic port '%s'\n",
optarg);
exit(1);
}
add_local_forward(&options, fwd_port, "socks", 0);
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;
if (process_config_line(&options, host ? host : "",
optarg, "command-line", 0, &dummy) != 0)
exit(1);
break;
case 's':
subsystem_flag = 1;
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)) && !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))
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);
/* Read systemwide configuration file after use config. */
(void)read_config_file(_PATH_HOST_CONFIG_FILE, host, &options);
}
/* 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 = tolower(*p);
}
if (options.proxy_command != NULL &&
strcmp(options.proxy_command, "none") == 0)
options.proxy_command = NULL;
/* 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(1);
/*
* 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 = xmalloc(sensitive_data.nkeys *
sizeof(Key));
PRIV_START;
sensitive_data.keys[0] = key_load_private_type(KEY_RSA1,
_PATH_HOST_KEY_FILE, "", NULL);
sensitive_data.keys[1] = key_load_private_type(KEY_DSA,
_PATH_HOST_DSA_KEY_FILE, "", NULL);
sensitive_data.keys[2] = key_load_private_type(KEY_RSA,
_PATH_HOST_RSA_KEY_FILE, "", 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.
*/
seteuid(original_real_uid);
setuid(original_real_uid);
/*
* 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();
/*
* 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;
}
#define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1"
static void
x11_get_proto(char **_proto, char **_data)
{
char cmd[1024];
char line[512];
char xdisplay[512];
static char proto[512], data[512];
FILE *f;
int got_data = 0, generated = 0, do_unlink = 0, i;
char *display, *xauthdir, *xauthfile;
struct stat st;
xauthdir = xauthfile = NULL;
*_proto = proto;
*_data = data;
proto[0] = data[0] = '\0';
if (!options.xauth_location ||
(stat(options.xauth_location, &st) == -1)) {
debug("No xauth program.");
} else {
if ((display = getenv("DISPLAY")) == NULL) {
debug("x11_get_proto: DISPLAY not set");
return;
}
/*
* Handle FamilyLocal case where $DISPLAY does
* not match an authorization entry. For this we
* just try "xauth list unix:displaynum.screennum".
* XXX: "localhost" match to determine FamilyLocal
* is not perfect.
*/
if (strncmp(display, "localhost:", 10) == 0) {
snprintf(xdisplay, sizeof(xdisplay), "unix:%s",
display + 10);
display = xdisplay;
}
if (options.forward_x11_trusted == 0) {
xauthdir = xmalloc(MAXPATHLEN);
xauthfile = xmalloc(MAXPATHLEN);
strlcpy(xauthdir, "/tmp/ssh-XXXXXXXXXX", MAXPATHLEN);
if (mkdtemp(xauthdir) != NULL) {
do_unlink = 1;
snprintf(xauthfile, MAXPATHLEN, "%s/xauthfile",
xauthdir);
snprintf(cmd, sizeof(cmd),
"%s -f %s generate %s " SSH_X11_PROTO
" untrusted timeout 120 2>" _PATH_DEVNULL,
options.xauth_location, xauthfile, display);
debug2("x11_get_proto: %s", cmd);
if (system(cmd) == 0)
generated = 1;
}
}
snprintf(cmd, sizeof(cmd),
"%s %s%s list %s . 2>" _PATH_DEVNULL,
options.xauth_location,
generated ? "-f " : "" ,
generated ? xauthfile : "",
display);
debug2("x11_get_proto: %s", cmd);
f = popen(cmd, "r");
if (f && fgets(line, sizeof(line), f) &&
sscanf(line, "%*s %511s %511s", proto, data) == 2)
got_data = 1;
if (f)
pclose(f);
}
if (do_unlink) {
unlink(xauthfile);
rmdir(xauthdir);
}
if (xauthdir)
xfree(xauthdir);
if (xauthfile)
xfree(xauthfile);
/*
* If we didn't get authentication data, just make up some
* data. The forwarding code will check the validity of the
* response anyway, and substitute this data. The X11
* server, however, will ignore this fake data and use
* whatever authentication mechanisms it was using otherwise
* for the local connection.
*/
if (!got_data) {
u_int32_t rand = 0;
logit("Warning: No xauth data; "
"using fake authentication data for X11 forwarding.");
strlcpy(proto, SSH_X11_PROTO, sizeof proto);
for (i = 0; i < 16; i++) {
if (i % 4 == 0)
rand = arc4random();
snprintf(data + 2 * i, sizeof data - 2 * i, "%02x",
rand & 0xff);
rand >>= 8;
}
}
}
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("Connections to local port %d forwarded to remote address %.200s:%d",
options.local_forwards[i].port,
options.local_forwards[i].host,
options.local_forwards[i].host_port);
success += channel_setup_local_fwd_listener(
options.local_forwards[i].port,
options.local_forwards[i].host,
options.local_forwards[i].host_port,
options.gateway_ports);
}
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("Connections to remote port %d forwarded to local address %.200s:%d",
options.remote_forwards[i].port,
options.remote_forwards[i].host,
options.remote_forwards[i].host_port);
channel_request_remote_forwarding(
options.remote_forwards[i].port,
options.remote_forwards[i].host,
options.remote_forwards[i].host_port);
}
}
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;
/* 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(ws.ws_row);
packet_put_int(ws.ws_col);
packet_put_int(ws.ws_xpixel);
packet_put_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. */
if (options.forward_x11 && getenv("DISPLAY") != NULL) {
char *proto, *data;
/* Get reasonable local authentication information. */
x11_get_proto(&proto, &data);
/* Request forwarding with authentication spoofing. */
debug("Requesting X11 forwarding with authentication spoofing.");
x11_request_forwarding_with_spoofing(0, 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
client_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(int type, u_int32_t seq, void *ctxt)
{
int i;
i = client_global_request_id++;
if (i >= options.num_remote_forwards) {
debug("client_global_request_reply: too many replies %d > %d",
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].port,
options.remote_forwards[i].host,
options.remote_forwards[i].host_port);
if (type == SSH2_MSG_REQUEST_FAILURE)
logit("Warning: remote port forwarding failed for listen port %d",
options.remote_forwards[i].port);
}
/* request pty/x11/agent/tcpfwd/shell for channel */
static void
ssh_session2_setup(int id, void *arg)
{
int len;
int interactive = 0;
struct termios tio;
debug2("ssh_session2_setup: id %d", id);
if (tty_flag) {
struct winsize ws;
char *cp;
cp = getenv("TERM");
if (!cp)
cp = "";
/* Store window size in the packet. */
if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
memset(&ws, 0, sizeof(ws));
channel_request_start(id, "pty-req", 0);
packet_put_cstring(cp);
packet_put_int(ws.ws_col);
packet_put_int(ws.ws_row);
packet_put_int(ws.ws_xpixel);
packet_put_int(ws.ws_ypixel);
tio = get_saved_tio();
tty_make_modes(/*ignored*/ 0, &tio);
packet_send();
interactive = 1;
/* XXX wait for reply */
}
if (options.forward_x11 &&
getenv("DISPLAY") != NULL) {
char *proto, *data;
/* Get reasonable local authentication information. */
x11_get_proto(&proto, &data);
/* Request forwarding with authentication spoofing. */
debug("Requesting X11 forwarding with authentication spoofing.");
x11_request_forwarding_with_spoofing(id, proto, data);
interactive = 1;
/* XXX wait for reply */
}
check_agent_present();
if (options.forward_agent) {
debug("Requesting authentication agent forwarding.");
channel_request_start(id, "auth-agent-req@openssh.com", 0);
packet_send();
}
len = buffer_len(&command);
if (len > 0) {
if (len > 900)
len = 900;
if (subsystem_flag) {
debug("Sending subsystem: %.*s", len, (u_char *)buffer_ptr(&command));
channel_request_start(id, "subsystem", /*want reply*/ 1);
/* register callback for reply */
/* XXX we assume that client_loop has already been called */
dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &client_subsystem_reply);
dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &client_subsystem_reply);
} else {
debug("Sending command: %.*s", len, (u_char *)buffer_ptr(&command));
channel_request_start(id, "exec", 0);
}
packet_put_string(buffer_ptr(&command), buffer_len(&command));
packet_send();
} else {
channel_request_start(id, "shell", 0);
packet_send();
}
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);
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();
/* 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;
int i = 0;
Key *public;
#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 */
for (; i < options.num_identity_files; i++) {
filename = tilde_expand_filename(options.identity_files[i],
original_real_uid);
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;
}
}
Reference in New Issue View Git Blame Copy Permalink