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/*
* 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.
*
* 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 1.94 2001/02/10 01:46:28 markus 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 "uidswap.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"
#ifdef HAVE___PROGNAME
extern char *__progname;
#else
char *__progname;
#endif
/* Flag indicating whether IPv4 or IPv6. This can be set on the command line.
Default value is AF_UNSPEC means both IPv4 and IPv6. */
#ifdef IPV4_DEFAULT
int IPv4or6 = AF_INET;
#else
int IPv4or6 = AF_UNSPEC;
#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 pasphrase 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;
/*
* 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;
/*
* Flag to indicate that we have received a window change signal which has
* not yet been processed. This will cause a message indicating the new
* window size to be sent to the server a little later. This is volatile
* because this is updated in a signal handler.
*/
volatile int received_window_change_signal = 0;
/* Flag indicating whether we have a valid host private key loaded. */
int host_private_key_loaded = 0;
/* Host private key. */
RSA *host_private_key = NULL;
/* Original real UID. */
uid_t original_real_uid;
/* command to be executed */
Buffer command;
/* Should we execute a command or invoke a subsystem? */
int subsystem_flag = 0;
/* Prints a help message to the user. This function never returns. */
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, " -A Enable authentication agent forwarding.\n");
fprintf(stderr, " -a Disable authentication agent forwarding.\n");
#ifdef AFS
fprintf(stderr, " -k Disable Kerberos ticket and AFS token forwarding.\n");
#endif /* AFS */
fprintf(stderr, " -X Enable X11 connection forwarding.\n");
fprintf(stderr, " -x Disable X11 connection forwarding.\n");
fprintf(stderr, " -i file Identity for RSA authentication (default: ~/.ssh/identity).\n");
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, " -P Don't allocate a privileged port.\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: "
"``3des'', "
"``blowfish''\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, " -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");
exit(1);
}
/*
* Connects to the given host using rsh (or prints an error message and exits
* if rsh is not available). This function never returns.
*/
void
rsh_connect(char *host, char *user, Buffer * command)
{
char *args[10];
int i;
log("Using rsh. WARNING: Connection will not be encrypted.");
/* Build argument list for rsh. */
i = 0;
args[i++] = _PATH_RSH;
/* host may have to come after user on some systems */
args[i++] = host;
if (user) {
args[i++] = "-l";
args[i++] = user;
}
if (buffer_len(command) > 0) {
buffer_append(command, "\0", 1);
args[i++] = buffer_ptr(command);
}
args[i++] = NULL;
if (debug_flag) {
for (i = 0; args[i]; i++) {
if (i != 0)
fprintf(stderr, " ");
fprintf(stderr, "%s", args[i]);
}
fprintf(stderr, "\n");
}
execv(_PATH_RSH, args);
perror(_PATH_RSH);
exit(1);
}
int ssh_session(void);
int ssh_session2(void);
int guess_identity_file_type(const char *filename);
/*
* Main program for the ssh client.
*/
int
main(int ac, char **av)
{
int i, opt, optind, exit_status, ok;
u_short fwd_port, fwd_host_port;
char *optarg, *cp, buf[256];
struct stat st;
struct passwd *pw, pwcopy;
int dummy;
uid_t original_effective_uid;
__progname = 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();
#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
/*
* 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).
*/
temporarily_use_uid(original_real_uid);
/*
* 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;
for (optind = 1; optind < ac; optind++) {
if (av[optind][0] != '-') {
if (host)
break;
if ((cp = strchr(av[optind], '@'))) {
if(cp == av[optind])
usage();
options.user = av[optind];
*cp = '\0';
host = ++cp;
} else
host = av[optind];
continue;
}
opt = av[optind][1];
if (!opt)
usage();
if (strchr("eilcpLRo", opt)) { /* options with arguments */
optarg = av[optind] + 2;
if (strcmp(optarg, "") == 0) {
if (optind >= ac - 1)
usage();
optarg = av[++optind];
}
} else {
if (av[optind][2])
usage();
optarg = NULL;
}
switch (opt) {
case '1':
options.protocol = SSH_PROTO_1;
break;
case '2':
options.protocol = SSH_PROTO_2;
break;
case '4':
IPv4or6 = AF_INET;
break;
case '6':
IPv4or6 = 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 'g':
options.gateway_ports = 1;
break;
case 'P':
options.use_privileged_port = 0;
break;
case 'a':
options.forward_agent = 0;
break;
case 'A':
options.forward_agent = 1;
break;
#ifdef AFS
case 'k':
options.kerberos_tgt_passing = 0;
options.afs_token_passing = 0;
break;
#endif
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 't':
if (tty_flag)
force_tty_flag = 1;
tty_flag = 1;
break;
case 'v':
if (0 == debug_flag) {
debug_flag = 1;
options.log_level = SYSLOG_LEVEL_DEBUG1;
} else if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
options.log_level++;
break;
} else {
fatal("Too high debugging level.\n");
}
/* fallthrough */
case 'V':
fprintf(stderr, "SSH Version %s, protocol versions %d.%d/%d.%d.\n",
SSH_VERSION,
PROTOCOL_MAJOR_1, PROTOCOL_MINOR_1,
PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2);
fprintf(stderr, "Compiled with SSL (0x%8.8lx).\n", SSLeay());
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 = -2;
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 'p':
options.port = atoi(optarg);
break;
case 'l':
options.user = optarg;
break;
case 'R':
if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf,
&fwd_host_port) != 3 &&
sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf,
&fwd_host_port) != 3) {
fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg);
usage();
/* NOTREACHED */
}
add_remote_forward(&options, fwd_port, buf, fwd_host_port);
break;
case 'L':
if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf,
&fwd_host_port) != 3 &&
sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf,
&fwd_host_port) != 3) {
fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg);
usage();
/* NOTREACHED */
}
add_local_forward(&options, fwd_port, buf, fwd_host_port);
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;
default:
usage();
}
}
/* 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 (optind == ac) {
/* No command specified - execute shell on a tty. */
tty_flag = 1;
if (subsystem_flag) {
fprintf(stderr, "You must specify a subsystem to invoke.");
usage();
}
} else {
/* A command has been specified. Store it into the
buffer. */
for (i = optind; i < ac; i++) {
if (i > optind)
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)
log("Pseudo-terminal will not be allocated because stdin is not a terminal.\n");
tty_flag = 0;
}
/* Get user data. */
pw = getpwuid(original_real_uid);
if (!pw) {
log("You don't exist, go away!\n");
exit(1);
}
/* Take a copy of the returned structure. */
memset(&pwcopy, 0, sizeof(pwcopy));
pwcopy.pw_name = xstrdup(pw->pw_name);
pwcopy.pw_passwd = xstrdup(pw->pw_passwd);
pwcopy.pw_uid = pw->pw_uid;
pwcopy.pw_gid = pw->pw_gid;
#ifdef HAVE_PW_CLASS_IN_PASSWD
pwcopy.pw_class = xstrdup(pw->pw_class);
#endif
pwcopy.pw_dir = xstrdup(pw->pw_dir);
pwcopy.pw_shell = xstrdup(pw->pw_shell);
pw = &pwcopy;
/* Initialize "log" output. Since we are the client all output
actually goes to the terminal. */
log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 0);
/* Read per-user configuration file. */
snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, _PATH_SSH_USER_CONFFILE);
read_config_file(buf, host, &options);
/* Read systemwide configuration file. */
read_config_file(_PATH_HOST_CONFIG_FILE, host, &options);
/* Fill configuration defaults. */
fill_default_options(&options);
/* reinit */
log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 0);
if (options.user == NULL)
options.user = xstrdup(pw->pw_name);
if (options.hostname != NULL)
host = options.hostname;
/* Disable rhosts authentication if not running as root. */
#ifdef HAVE_CYGWIN
/* Ignore uid if running under Windows */
if (!options.use_privileged_port) {
#else
if (original_effective_uid != 0 || !options.use_privileged_port) {
#endif
debug("Rhosts Authentication disabled, "
"originating port will not be trusted.");
options.rhosts_authentication = 0;
}
/*
* If using rsh has been selected, exec it now (without trying
* anything else). Note that we must release privileges first.
*/
if (options.use_rsh) {
/*
* Restore our superuser privileges. This must be done
* before permanently setting the uid.
*/
restore_uid();
/* Switch to the original uid permanently. */
permanently_set_uid(original_real_uid);
/* Execute rsh. */
rsh_connect(host, options.user, &command);
fatal("rsh_connect returned");
}
/* Restore our superuser privileges. */
restore_uid();
/* Open a connection to the remote host. */
ok = ssh_connect(host, &hostaddr, options.port,
options.connection_attempts,
original_effective_uid != 0 || !options.use_privileged_port,
original_real_uid,
options.proxy_command);
/*
* 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 (ok && (options.protocol & SSH_PROTO_1)) {
Key k;
host_private_key = RSA_new();
k.type = KEY_RSA1;
k.rsa = host_private_key;
if (load_private_key(_PATH_HOST_KEY_FILE, "", &k, NULL))
host_private_key_loaded = 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.
*/
/*
* Note that some legacy systems need to postpone the following call
* to permanently_set_uid() until the private hostkey is destroyed
* with RSA_free(). Otherwise the calling user could ptrace() the
* process, read the private hostkey and impersonate the host.
* OpenBSD does not allow ptracing of setuid processes.
*/
permanently_set_uid(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/%.100s", pw->pw_dir, _PATH_SSH_USER_DIR);
if (stat(buf, &st) < 0)
if (mkdir(buf, 0700) < 0)
error("Could not create directory '%.200s'.", buf);
/* Check if the connection failed, and try "rsh" if appropriate. */
if (!ok) {
if (options.port != 0)
log("Secure connection to %.100s on port %hu refused%.100s.",
host, options.port,
options.fallback_to_rsh ? "; reverting to insecure method" : "");
else
log("Secure connection to %.100s refused%.100s.", host,
options.fallback_to_rsh ? "; reverting to insecure method" : "");
if (options.fallback_to_rsh) {
rsh_connect(host, options.user, &command);
fatal("rsh_connect returned");
}
exit(1);
}
/* Expand ~ in options.identity_files, known host file names. */
/* XXX mem-leaks */
for (i = 0; i < options.num_identity_files; i++) {
options.identity_files[i] =
tilde_expand_filename(options.identity_files[i], original_real_uid);
options.identity_files_type[i] = guess_identity_file_type(options.identity_files[i]);
debug("identity file %s type %d", options.identity_files[i],
options.identity_files_type[i]);
}
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);
/* Log into the remote system. This never returns if the login fails. */
ssh_login(host_private_key_loaded, host_private_key,
host, (struct sockaddr *)&hostaddr, original_real_uid);
/* We no longer need the host private key. Clear it now. */
if (host_private_key_loaded)
RSA_free(host_private_key); /* Destroys contents safely */
exit_status = compat20 ? ssh_session2() : ssh_session();
packet_close();
return exit_status;
}
void
x11_get_proto(char *proto, int proto_len, char *data, int data_len)
{
char line[512];
FILE *f;
int got_data = 0, i;
if (options.xauth_location) {
/* Try to get Xauthority information for the display. */
snprintf(line, sizeof line, "%.100s list %.200s 2>" _PATH_DEVNULL,
options.xauth_location, getenv("DISPLAY"));
f = popen(line, "r");
if (f && fgets(line, sizeof(line), f) &&
sscanf(line, "%*s %s %s", proto, data) == 2)
got_data = 1;
if (f)
pclose(f);
}
/*
* 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;
strlcpy(proto, "MIT-MAGIC-COOKIE-1", proto_len);
for (i = 0; i < 16; i++) {
if (i % 4 == 0)
rand = arc4random();
snprintf(data + 2 * i, data_len - 2 * i, "%02x", rand & 0xff);
rand >>= 8;
}
}
}
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_request_local_forwarding(
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);
}
}
void
check_agent_present(void)
{
if (options.forward_agent) {
/* Clear agent forwarding if we don\'t have an agent. */
int authfd = ssh_get_authentication_socket();
if (authfd < 0)
options.forward_agent = 0;
else
ssh_close_authentication_socket(authfd);
}
}
int
ssh_session(void)
{
int type;
int plen;
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(&plen);
if (type == SSH_SMSG_SUCCESS)
packet_start_compression(options.compression_level);
else if (type == SSH_SMSG_FAILURE)
log("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_string(cp, strlen(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));
/* Send the packet, and wait for it to leave. */
packet_send();
packet_write_wait();
/* Read response from the server. */
type = packet_read(&plen);
if (type == SSH_SMSG_SUCCESS) {
interactive = 1;
have_tty = 1;
} else if (type == SSH_SMSG_FAILURE)
log("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[512], data[512];
/* Get reasonable local authentication information. */
x11_get_proto(proto, sizeof proto, data, sizeof 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(&plen);
if (type == SSH_SMSG_SUCCESS) {
interactive = 1;
} else if (type == SSH_SMSG_FAILURE) {
log("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(&plen);
packet_integrity_check(plen, 0, type);
if (type != SSH_SMSG_SUCCESS)
log("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, 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 : -1, 0);
}
void
client_subsystem_reply(int type, int plen, void *ctxt)
{
int id, len;
id = packet_get_int();
len = buffer_len(&command);
len = MAX(len, 900);
packet_done();
if (type == SSH2_MSG_CHANNEL_FAILURE)
fatal("Request for subsystem '%.*s' failed on channel %d",
len, buffer_ptr(&command), id);
}
void
ssh_session2_callback(int id, void *arg)
{
int len;
int interactive = 0;
debug("client_init id %d arg %ld", id, (long)arg);
if (no_shell_flag)
goto done;
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);
packet_put_cstring(""); /* XXX: encode terminal modes */
packet_send();
interactive = 1;
/* XXX wait for reply */
}
if (options.forward_x11 &&
getenv("DISPLAY") != NULL) {
char proto[512], data[512];
/* Get reasonable local authentication information. */
x11_get_proto(proto, sizeof proto, data, sizeof 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, buffer_ptr(&command));
channel_request_start(id, "subsystem", /*want reply*/ 1);
/* register callback for reply */
/* XXX we asume 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, buffer_ptr(&command));
channel_request_start(id, "exec", 0);
}
packet_put_string(buffer_ptr(&command), len);
packet_send();
} else {
channel_request(id, "shell", 0);
}
/* channel_callback(id, SSH2_MSG_OPEN_CONFIGMATION, client_init, 0); */
done:
/* register different callback, etc. XXX */
packet_set_interactive(interactive);
}
int
ssh_session2(void)
{
int window, packetmax, id;
int 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);
/* XXX should be pre-session */
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));
window = CHAN_SES_WINDOW_DEFAULT;
packetmax = CHAN_SES_PACKET_DEFAULT;
if (!tty_flag) {
window *= 2;
packetmax *=2;
}
id = channel_new(
"session", SSH_CHANNEL_OPENING, in, out, err,
window, packetmax, CHAN_EXTENDED_WRITE,
xstrdup("client-session"), /*nonblock*/0);
channel_open(id);
channel_register_callback(id, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION,
ssh_session2_callback, (void *)0);
return client_loop(tty_flag, tty_flag ? options.escape_char : -1, id);
}
int
guess_identity_file_type(const char *filename)
{
struct stat st;
Key *public;
int type = KEY_RSA1; /* default */
if (stat(filename, &st) < 0) {
/* ignore this key */
return KEY_UNSPEC;
}
public = key_new(type);
if (!load_public_key(filename, public, NULL)) {
/* ok, so we will assume this is 'some' key */
type = KEY_UNSPEC;
}
key_free(public);
return type;
}
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