21deafa350
In some cases, limits did not get set to the proper class, but instead always to "default", because not all passwd copies were done to completion.
985 lines
28 KiB
C
985 lines
28 KiB
C
/*
|
|
* Author: Tatu Ylonen <ylo@cs.hut.fi>
|
|
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
|
|
* All rights reserved
|
|
* Created: Sat Mar 18 16:36:11 1995 ylo
|
|
* 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.
|
|
*
|
|
* Modified to work with SSL by Niels Provos <provos@citi.umich.edu> in Canada.
|
|
*
|
|
* $FreeBSD$
|
|
*/
|
|
|
|
#include "includes.h"
|
|
RCSID("$Id: ssh.c,v 1.54 2000/05/30 17:32:06 markus Exp $");
|
|
|
|
#include <openssl/evp.h>
|
|
#include <openssl/dsa.h>
|
|
#include <openssl/rsa.h>
|
|
|
|
#include "xmalloc.h"
|
|
#include "ssh.h"
|
|
#include "packet.h"
|
|
#include "buffer.h"
|
|
#include "authfd.h"
|
|
#include "readconf.h"
|
|
#include "uidswap.h"
|
|
|
|
#include "ssh2.h"
|
|
#include "compat.h"
|
|
#include "channels.h"
|
|
#include "key.h"
|
|
#include "authfile.h"
|
|
|
|
extern char *__progname;
|
|
|
|
/* Flag indicating whether IPv4 or IPv6. This can be set on the command line.
|
|
Default value is AF_UNSPEC means both IPv4 and IPv6. */
|
|
int IPv4or6 = AF_UNSPEC;
|
|
|
|
/* 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;
|
|
|
|
/* don't exec a shell */
|
|
int no_shell_flag = 0;
|
|
int no_tty_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;
|
|
|
|
/* Value of argv[0] (set in the main program). */
|
|
char *av0;
|
|
|
|
/* 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;
|
|
|
|
/* Prints a help message to the user. This function never returns. */
|
|
|
|
void
|
|
usage()
|
|
{
|
|
fprintf(stderr, "Usage: %s [options] host [command]\n", av0);
|
|
fprintf(stderr, "Options:\n");
|
|
fprintf(stderr, " -l user Log in using this user name.\n");
|
|
fprintf(stderr, " -n Redirect input from /dev/null.\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, " -X Enable 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, " -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", av0);
|
|
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, " -4 Use IPv4 only.\n");
|
|
fprintf(stderr, " -6 Use IPv6 only.\n");
|
|
fprintf(stderr, " -2 Force protocol version 2.\n");
|
|
fprintf(stderr, " -o 'option' Process the option as if it was read from a configuration file.\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;
|
|
#ifndef _PATH_RSH
|
|
#define _PATH_RSH "/usr/bin/rsh"
|
|
#endif
|
|
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);
|
|
|
|
/*
|
|
* 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;
|
|
|
|
/*
|
|
* 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();
|
|
|
|
/* 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));
|
|
}
|
|
/*
|
|
* 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);
|
|
|
|
/* Save our own name. */
|
|
av0 = av[0];
|
|
|
|
/* Initialize option structure to indicate that no values have been set. */
|
|
initialize_options(&options);
|
|
|
|
/* Parse command-line arguments. */
|
|
host = NULL;
|
|
|
|
/* If program name is not one of the standard names, use it as host name. */
|
|
if (strchr(av0, '/'))
|
|
cp = strrchr(av0, '/') + 1;
|
|
else
|
|
cp = av0;
|
|
if (strcmp(cp, "rsh") != 0 && strcmp(cp, "ssh") != 0 &&
|
|
strcmp(cp, "rlogin") != 0 && strcmp(cp, "slogin") != 0)
|
|
host = cp;
|
|
|
|
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 '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.krb4_tgt_passing = 0;
|
|
options.krb5_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':
|
|
tty_flag = 1;
|
|
break;
|
|
case 'v':
|
|
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);
|
|
debug_flag = 1;
|
|
options.log_level = SYSLOG_LEVEL_DEBUG;
|
|
break;
|
|
case 'q':
|
|
options.log_level = SYSLOG_LEVEL_QUIET;
|
|
break;
|
|
case 'e':
|
|
if (optarg[0] == '^' && optarg[2] == 0 &&
|
|
(unsigned char) optarg[1] >= 64 && (unsigned char) optarg[1] < 128)
|
|
options.escape_char = (unsigned char) optarg[1] & 31;
|
|
else if (strlen(optarg) == 1)
|
|
options.escape_char = (unsigned 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);
|
|
}
|
|
}
|
|
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;
|
|
default:
|
|
usage();
|
|
}
|
|
}
|
|
|
|
/* Check that we got a host name. */
|
|
if (!host)
|
|
usage();
|
|
|
|
SSLeay_add_all_algorithms();
|
|
|
|
/* 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;
|
|
} 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)
|
|
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;
|
|
|
|
/* Do not allocate a tty if stdin is not a tty. */
|
|
if (!isatty(fileno(stdin))) {
|
|
if (tty_flag)
|
|
fprintf(stderr, "Pseudo-terminal will not be allocated because stdin is not a terminal.\n");
|
|
tty_flag = 0;
|
|
}
|
|
/* force */
|
|
if (no_tty_flag)
|
|
tty_flag = 0;
|
|
|
|
/* Get user data. */
|
|
pw = getpwuid(original_real_uid);
|
|
if (!pw) {
|
|
fprintf(stderr, "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;
|
|
pwcopy.pw_dir = xstrdup(pw->pw_dir);
|
|
pwcopy.pw_shell = xstrdup(pw->pw_shell);
|
|
pwcopy.pw_class = xstrdup(pw->pw_class);
|
|
pwcopy.pw_expire = pw->pw_expire;
|
|
pwcopy.pw_change = pw->pw_change;
|
|
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, SSH_USER_CONFFILE);
|
|
read_config_file(buf, host, &options);
|
|
|
|
/* Read systemwide configuration file. */
|
|
read_config_file(HOST_CONFIG_FILE, host, &options);
|
|
|
|
/* Fill configuration defaults. */
|
|
fill_default_options(&options);
|
|
|
|
/* reinit */
|
|
log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 0);
|
|
|
|
/* check if RSA support exists */
|
|
if ((options.protocol & SSH_PROTO_1) &&
|
|
rsa_alive() == 0) {
|
|
log("%s: no RSA support in libssl and libcrypto. See ssl(8).",
|
|
__progname);
|
|
log("Disabling protocol version 1");
|
|
options.protocol &= ~ (SSH_PROTO_1|SSH_PROTO_1_PREFERRED);
|
|
}
|
|
if (! options.protocol & (SSH_PROTO_1|SSH_PROTO_2)) {
|
|
fprintf(stderr, "%s: No protocol version available.\n",
|
|
__progname);
|
|
exit(1);
|
|
}
|
|
|
|
if (options.user == NULL)
|
|
options.user = xstrdup(pw->pw_name);
|
|
|
|
if (options.hostname != NULL)
|
|
host = options.hostname;
|
|
|
|
/* Find canonic host name. */
|
|
if (strchr(host, '.') == 0) {
|
|
struct addrinfo hints;
|
|
struct addrinfo *ai = NULL;
|
|
int errgai;
|
|
memset(&hints, 0, sizeof(hints));
|
|
hints.ai_family = IPv4or6;
|
|
hints.ai_flags = AI_CANONNAME;
|
|
hints.ai_socktype = SOCK_STREAM;
|
|
errgai = getaddrinfo(host, NULL, &hints, &ai);
|
|
if (errgai == 0) {
|
|
if (ai->ai_canonname != NULL)
|
|
host = xstrdup(ai->ai_canonname);
|
|
freeaddrinfo(ai);
|
|
}
|
|
}
|
|
/* Disable rhosts authentication if not running as root. */
|
|
if (original_effective_uid != 0 || !options.use_privileged_port) {
|
|
options.rhosts_authentication = 0;
|
|
options.rhosts_rsa_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. This needs root privileges
|
|
* if rhosts_{rsa_}authentication is enabled.
|
|
*/
|
|
|
|
ok = ssh_connect(host, &hostaddr, options.port,
|
|
options.connection_attempts,
|
|
!options.rhosts_authentication &&
|
|
!options.rhosts_rsa_authentication,
|
|
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_RSA;
|
|
k.rsa = host_private_key;
|
|
if (load_private_key(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, SSH_USER_DIR);
|
|
if (stat(buf, &st) < 0)
|
|
if (mkdir(buf, 0755) < 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. */
|
|
/* 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);
|
|
for (i = 0; i < options.num_identity_files2; i++)
|
|
options.identity_files2[i] =
|
|
tilde_expand_filename(options.identity_files2[i], original_real_uid);
|
|
/* Expand ~ in known host file names. */
|
|
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;
|
|
|
|
#ifdef XAUTH_PATH
|
|
/* Try to get Xauthority information for the display. */
|
|
snprintf(line, sizeof line, "%.100s list %.200s 2>/dev/null",
|
|
XAUTH_PATH, 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);
|
|
#endif /* XAUTH_PATH */
|
|
/*
|
|
* 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;
|
|
}
|
|
}
|
|
}
|
|
|
|
int
|
|
ssh_session(void)
|
|
{
|
|
int type;
|
|
int i;
|
|
int plen;
|
|
int interactive = 0;
|
|
int have_tty = 0;
|
|
struct winsize ws;
|
|
int authfd;
|
|
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, options.keepalives);
|
|
|
|
/* Clear agent forwarding if we don\'t have an agent. */
|
|
authfd = ssh_get_authentication_socket();
|
|
if (authfd < 0)
|
|
options.forward_agent = 0;
|
|
else
|
|
ssh_close_authentication_socket(authfd);
|
|
|
|
/* Request authentication agent forwarding if appropriate. */
|
|
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 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);
|
|
channel_request_local_forwarding(options.local_forwards[i].port,
|
|
options.local_forwards[i].host,
|
|
options.local_forwards[i].host_port,
|
|
options.gateway_ports);
|
|
}
|
|
|
|
/* 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);
|
|
}
|
|
|
|
/* 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);
|
|
}
|
|
|
|
void
|
|
init_local_fwd(void)
|
|
{
|
|
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);
|
|
channel_request_local_forwarding(options.local_forwards[i].port,
|
|
options.local_forwards[i].host,
|
|
options.local_forwards[i].host_port,
|
|
options.gateway_ports);
|
|
}
|
|
}
|
|
|
|
extern void client_set_session_ident(int id);
|
|
|
|
void
|
|
client_init(int id, void *arg)
|
|
{
|
|
int len;
|
|
debug("client_init id %d arg %d", id, (int)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();
|
|
/* 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);
|
|
/* XXX wait for reply */
|
|
}
|
|
|
|
len = buffer_len(&command);
|
|
if (len > 0) {
|
|
if (len > 900)
|
|
len = 900;
|
|
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 */
|
|
client_set_session_ident(id);
|
|
}
|
|
|
|
int
|
|
ssh_session2(void)
|
|
{
|
|
int window, packetmax, id;
|
|
int in = dup(STDIN_FILENO);
|
|
int out = dup(STDOUT_FILENO);
|
|
int err = dup(STDERR_FILENO);
|
|
|
|
if (in < 0 || out < 0 || err < 0)
|
|
fatal("dump in/out/err failed");
|
|
|
|
/* should be pre-session */
|
|
init_local_fwd();
|
|
|
|
window = 32*1024;
|
|
if (tty_flag) {
|
|
packetmax = window/8;
|
|
} else {
|
|
window *= 2;
|
|
packetmax = window/2;
|
|
}
|
|
|
|
id = channel_new(
|
|
"session", SSH_CHANNEL_OPENING, in, out, err,
|
|
window, packetmax, CHAN_EXTENDED_WRITE, xstrdup("client-session"));
|
|
|
|
|
|
channel_open(id);
|
|
channel_register_callback(id, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, client_init, (void *)0);
|
|
|
|
return client_loop(tty_flag, tty_flag ? options.escape_char : -1);
|
|
}
|