810 lines
24 KiB
C
810 lines
24 KiB
C
/*
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* Author: Tatu Ylonen <ylo@cs.hut.fi>
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* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
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* All rights reserved
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* Created: Sat Mar 18 16:36:11 1995 ylo
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* Ssh client program. This program can be used to log into a remote machine.
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* The software supports strong authentication, encryption, and forwarding
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* of X11, TCP/IP, and authentication connections.
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*
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* Modified to work with SSL by Niels Provos <provos@citi.umich.edu> in Canada.
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*
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* $FreeBSD$
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*/
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#include "includes.h"
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RCSID("$Id: ssh.c,v 1.43 2000/03/23 21:52:02 markus Exp $");
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#include "xmalloc.h"
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#include "ssh.h"
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#include "packet.h"
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#include "buffer.h"
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#include "authfd.h"
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#include "readconf.h"
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#include "uidswap.h"
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/* Flag indicating whether IPv4 or IPv6. This can be set on the command line.
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Default value is AF_UNSPEC means both IPv4 and IPv6. */
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int IPv4or6 = AF_UNSPEC;
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/* Flag indicating whether debug mode is on. This can be set on the command line. */
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int debug_flag = 0;
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int tty_flag = 0;
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/*
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* Flag indicating that nothing should be read from stdin. This can be set
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* on the command line.
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*/
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int stdin_null_flag = 0;
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/*
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* Flag indicating that ssh should fork after authentication. This is useful
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* so that the pasphrase can be entered manually, and then ssh goes to the
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* background.
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*/
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int fork_after_authentication_flag = 0;
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/*
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* General data structure for command line options and options configurable
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* in configuration files. See readconf.h.
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*/
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Options options;
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/*
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* Name of the host we are connecting to. This is the name given on the
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* command line, or the HostName specified for the user-supplied name in a
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* configuration file.
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*/
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char *host;
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/* socket address the host resolves to */
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struct sockaddr_storage hostaddr;
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/*
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* Flag to indicate that we have received a window change signal which has
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* not yet been processed. This will cause a message indicating the new
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* window size to be sent to the server a little later. This is volatile
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* because this is updated in a signal handler.
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*/
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volatile int received_window_change_signal = 0;
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/* Value of argv[0] (set in the main program). */
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char *av0;
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/* Flag indicating whether we have a valid host private key loaded. */
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int host_private_key_loaded = 0;
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/* Host private key. */
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RSA *host_private_key = NULL;
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/* Original real UID. */
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uid_t original_real_uid;
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/* Prints a help message to the user. This function never returns. */
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void
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usage()
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{
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fprintf(stderr, "Usage: %s [options] host [command]\n", av0);
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fprintf(stderr, "Options:\n");
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fprintf(stderr, " -l user Log in using this user name.\n");
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fprintf(stderr, " -n Redirect input from /dev/null.\n");
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fprintf(stderr, " -a Disable authentication agent forwarding.\n");
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#ifdef AFS
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fprintf(stderr, " -k Disable Kerberos ticket and AFS token forwarding.\n");
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#endif /* AFS */
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fprintf(stderr, " -x Disable X11 connection forwarding.\n");
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fprintf(stderr, " -X Enable X11 connection forwarding.\n");
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fprintf(stderr, " -i file Identity for RSA authentication (default: ~/.ssh/identity).\n");
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fprintf(stderr, " -t Tty; allocate a tty even if command is given.\n");
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fprintf(stderr, " -v Verbose; display verbose debugging messages.\n");
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fprintf(stderr, " -V Display version number only.\n");
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fprintf(stderr, " -P Don't allocate a privileged port.\n");
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fprintf(stderr, " -q Quiet; don't display any warning messages.\n");
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fprintf(stderr, " -f Fork into background after authentication.\n");
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fprintf(stderr, " -e char Set escape character; ``none'' = disable (default: ~).\n");
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fprintf(stderr, " -c cipher Select encryption algorithm: "
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"``3des'', "
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"``blowfish''\n");
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fprintf(stderr, " -p port Connect to this port. Server must be on the same port.\n");
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fprintf(stderr, " -L listen-port:host:port Forward local port to remote address\n");
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fprintf(stderr, " -R listen-port:host:port Forward remote port to local address\n");
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fprintf(stderr, " These cause %s to listen for connections on a port, and\n", av0);
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fprintf(stderr, " forward them to the other side by connecting to host:port.\n");
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fprintf(stderr, " -C Enable compression.\n");
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fprintf(stderr, " -g Allow remote hosts to connect to forwarded ports.\n");
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fprintf(stderr, " -4 Use IPv4 only.\n");
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fprintf(stderr, " -6 Use IPv6 only.\n");
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fprintf(stderr, " -o 'option' Process the option as if it was read from a configuration file.\n");
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exit(1);
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}
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/*
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* Connects to the given host using rsh (or prints an error message and exits
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* if rsh is not available). This function never returns.
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*/
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void
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rsh_connect(char *host, char *user, Buffer * command)
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{
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char *args[10];
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int i;
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log("Using rsh. WARNING: Connection will not be encrypted.");
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/* Build argument list for rsh. */
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i = 0;
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#ifndef _PATH_RSH
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#define _PATH_RSH "/usr/bin/rsh"
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#endif
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args[i++] = _PATH_RSH;
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/* host may have to come after user on some systems */
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args[i++] = host;
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if (user) {
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args[i++] = "-l";
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args[i++] = user;
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}
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if (buffer_len(command) > 0) {
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buffer_append(command, "\0", 1);
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args[i++] = buffer_ptr(command);
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}
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args[i++] = NULL;
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if (debug_flag) {
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for (i = 0; args[i]; i++) {
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if (i != 0)
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fprintf(stderr, " ");
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fprintf(stderr, "%s", args[i]);
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}
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fprintf(stderr, "\n");
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}
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execv(_PATH_RSH, args);
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perror(_PATH_RSH);
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exit(1);
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}
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/*
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* Main program for the ssh client.
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*/
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int
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main(int ac, char **av)
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{
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int i, opt, optind, type, exit_status, ok, authfd;
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u_short fwd_port, fwd_host_port;
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char *optarg, *cp, buf[256];
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Buffer command;
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struct winsize ws;
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struct stat st;
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struct passwd *pw, pwcopy;
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int interactive = 0, dummy;
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int have_pty = 0;
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uid_t original_effective_uid;
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int plen;
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/*
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* Save the original real uid. It will be needed later (uid-swapping
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* may clobber the real uid).
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*/
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original_real_uid = getuid();
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original_effective_uid = geteuid();
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/* If we are installed setuid root be careful to not drop core. */
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if (original_real_uid != original_effective_uid) {
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struct rlimit rlim;
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rlim.rlim_cur = rlim.rlim_max = 0;
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if (setrlimit(RLIMIT_CORE, &rlim) < 0)
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fatal("setrlimit failed: %.100s", strerror(errno));
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}
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/*
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* Use uid-swapping to give up root privileges for the duration of
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* option processing. We will re-instantiate the rights when we are
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* ready to create the privileged port, and will permanently drop
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* them when the port has been created (actually, when the connection
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* has been made, as we may need to create the port several times).
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*/
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temporarily_use_uid(original_real_uid);
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/*
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* Set our umask to something reasonable, as some files are created
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* with the default umask. This will make them world-readable but
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* writable only by the owner, which is ok for all files for which we
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* don't set the modes explicitly.
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*/
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umask(022);
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/* Save our own name. */
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av0 = av[0];
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/* Initialize option structure to indicate that no values have been set. */
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initialize_options(&options);
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/* Parse command-line arguments. */
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host = NULL;
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/* If program name is not one of the standard names, use it as host name. */
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if (strchr(av0, '/'))
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cp = strrchr(av0, '/') + 1;
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else
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cp = av0;
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if (strcmp(cp, "rsh") != 0 && strcmp(cp, "ssh") != 0 &&
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strcmp(cp, "rlogin") != 0 && strcmp(cp, "slogin") != 0)
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host = cp;
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for (optind = 1; optind < ac; optind++) {
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if (av[optind][0] != '-') {
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if (host)
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break;
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if ((cp = strchr(av[optind], '@'))) {
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if(cp == av[optind])
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usage();
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options.user = av[optind];
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*cp = '\0';
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host = ++cp;
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} else
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host = av[optind];
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continue;
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}
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opt = av[optind][1];
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if (!opt)
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usage();
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if (strchr("eilcpLRo", opt)) { /* options with arguments */
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optarg = av[optind] + 2;
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if (strcmp(optarg, "") == 0) {
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if (optind >= ac - 1)
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usage();
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optarg = av[++optind];
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}
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} else {
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if (av[optind][2])
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usage();
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optarg = NULL;
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}
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switch (opt) {
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case '4':
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IPv4or6 = AF_INET;
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break;
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case '6':
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IPv4or6 = AF_INET6;
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break;
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case 'n':
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stdin_null_flag = 1;
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break;
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case 'f':
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fork_after_authentication_flag = 1;
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stdin_null_flag = 1;
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break;
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case 'x':
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options.forward_x11 = 0;
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break;
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case 'X':
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options.forward_x11 = 1;
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break;
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case 'g':
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options.gateway_ports = 1;
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break;
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case 'P':
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options.use_privileged_port = 0;
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break;
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case 'a':
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options.forward_agent = 0;
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break;
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#ifdef AFS
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case 'k':
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options.krb4_tgt_passing = 0;
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options.krb5_tgt_passing = 0;
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options.afs_token_passing = 0;
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break;
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#endif
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case 'i':
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if (stat(optarg, &st) < 0) {
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fprintf(stderr, "Warning: Identity file %s does not exist.\n",
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optarg);
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break;
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}
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if (options.num_identity_files >= SSH_MAX_IDENTITY_FILES)
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fatal("Too many identity files specified (max %d)",
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SSH_MAX_IDENTITY_FILES);
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options.identity_files[options.num_identity_files++] =
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xstrdup(optarg);
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break;
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case 't':
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tty_flag = 1;
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break;
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case 'v':
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case 'V':
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fprintf(stderr, "SSH Version %s, protocol version %d.%d.\n",
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SSH_VERSION, PROTOCOL_MAJOR, PROTOCOL_MINOR);
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fprintf(stderr, "Compiled with SSL.\n");
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if (opt == 'V')
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exit(0);
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debug_flag = 1;
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options.log_level = SYSLOG_LEVEL_DEBUG;
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break;
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case 'q':
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options.log_level = SYSLOG_LEVEL_QUIET;
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break;
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case 'e':
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if (optarg[0] == '^' && optarg[2] == 0 &&
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(unsigned char) optarg[1] >= 64 && (unsigned char) optarg[1] < 128)
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options.escape_char = (unsigned char) optarg[1] & 31;
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else if (strlen(optarg) == 1)
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options.escape_char = (unsigned char) optarg[0];
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else if (strcmp(optarg, "none") == 0)
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options.escape_char = -2;
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else {
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fprintf(stderr, "Bad escape character '%s'.\n", optarg);
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exit(1);
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}
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break;
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case 'c':
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options.cipher = cipher_number(optarg);
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if (options.cipher == -1) {
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fprintf(stderr, "Unknown cipher type '%s'\n", optarg);
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exit(1);
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}
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break;
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case 'p':
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options.port = atoi(optarg);
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break;
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case 'l':
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options.user = optarg;
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break;
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case 'R':
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if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf,
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&fwd_host_port) != 3 &&
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sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf,
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&fwd_host_port) != 3) {
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fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg);
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usage();
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/* NOTREACHED */
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}
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add_remote_forward(&options, fwd_port, buf, fwd_host_port);
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break;
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case 'L':
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if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf,
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&fwd_host_port) != 3 &&
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sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf,
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&fwd_host_port) != 3) {
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fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg);
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usage();
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/* NOTREACHED */
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}
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add_local_forward(&options, fwd_port, buf, fwd_host_port);
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break;
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case 'C':
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options.compression = 1;
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break;
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case 'o':
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dummy = 1;
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if (process_config_line(&options, host ? host : "", optarg,
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"command-line", 0, &dummy) != 0)
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exit(1);
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break;
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default:
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usage();
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}
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}
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/* Check that we got a host name. */
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if (!host)
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usage();
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/* check if RSA support exists */
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if (rsa_alive() == 0) {
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extern char *__progname;
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fprintf(stderr,
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"%s: no RSA support in libssl and libcrypto. See ssl(8).\n",
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__progname);
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exit(1);
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}
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/* Initialize the command to execute on remote host. */
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buffer_init(&command);
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/*
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* Save the command to execute on the remote host in a buffer. There
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* is no limit on the length of the command, except by the maximum
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* packet size. Also sets the tty flag if there is no command.
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*/
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if (optind == ac) {
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/* No command specified - execute shell on a tty. */
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tty_flag = 1;
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} else {
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/* A command has been specified. Store it into the
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buffer. */
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for (i = optind; i < ac; i++) {
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if (i > optind)
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buffer_append(&command, " ", 1);
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buffer_append(&command, av[i], strlen(av[i]));
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}
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}
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/* Cannot fork to background if no command. */
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if (fork_after_authentication_flag && buffer_len(&command) == 0)
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fatal("Cannot fork into background without a command to execute.");
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/* Allocate a tty by default if no command specified. */
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if (buffer_len(&command) == 0)
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tty_flag = 1;
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/* Do not allocate a tty if stdin is not a tty. */
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if (!isatty(fileno(stdin))) {
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if (tty_flag)
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fprintf(stderr, "Pseudo-terminal will not be allocated because stdin is not a terminal.\n");
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tty_flag = 0;
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}
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/* Get user data. */
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pw = getpwuid(original_real_uid);
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if (!pw) {
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fprintf(stderr, "You don't exist, go away!\n");
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exit(1);
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}
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/* Take a copy of the returned structure. */
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memset(&pwcopy, 0, sizeof(pwcopy));
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pwcopy.pw_name = xstrdup(pw->pw_name);
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pwcopy.pw_passwd = xstrdup(pw->pw_passwd);
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pwcopy.pw_uid = pw->pw_uid;
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pwcopy.pw_gid = pw->pw_gid;
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pwcopy.pw_dir = xstrdup(pw->pw_dir);
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pwcopy.pw_shell = xstrdup(pw->pw_shell);
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pw = &pwcopy;
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/* Initialize "log" output. Since we are the client all output
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actually goes to the terminal. */
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log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 0);
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/* Read per-user configuration file. */
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snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, SSH_USER_CONFFILE);
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read_config_file(buf, host, &options);
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/* Read systemwide configuration file. */
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read_config_file(HOST_CONFIG_FILE, host, &options);
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/* Fill configuration defaults. */
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fill_default_options(&options);
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/* reinit */
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log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 0);
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if (options.user == NULL)
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options.user = xstrdup(pw->pw_name);
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if (options.hostname != NULL)
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host = options.hostname;
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/* Find canonic host name. */
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if (strchr(host, '.') == 0) {
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struct addrinfo hints;
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struct addrinfo *ai = NULL;
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int errgai;
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memset(&hints, 0, sizeof(hints));
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hints.ai_family = IPv4or6;
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hints.ai_flags = AI_CANONNAME;
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hints.ai_socktype = SOCK_STREAM;
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errgai = getaddrinfo(host, NULL, &hints, &ai);
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if (errgai == 0) {
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if (ai->ai_canonname != NULL)
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host = xstrdup(ai->ai_canonname);
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freeaddrinfo(ai);
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}
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}
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/* Disable rhosts authentication if not running as root. */
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if (original_effective_uid != 0 || !options.use_privileged_port) {
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options.rhosts_authentication = 0;
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options.rhosts_rsa_authentication = 0;
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|
}
|
|
/*
|
|
* 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) {
|
|
host_private_key = RSA_new();
|
|
if (load_private_key(HOST_KEY_FILE, "", host_private_key, 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. */
|
|
for (i = 0; i < options.num_identity_files; i++)
|
|
options.identity_files[i] =
|
|
tilde_expand_filename(options.identity_files[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);
|
|
|
|
/* 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 */
|
|
|
|
/* 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_pty = 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 line[512], proto[512], data[512];
|
|
FILE *f;
|
|
int forwarded = 0, 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", 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;
|
|
}
|
|
}
|
|
/*
|
|
* Got local authentication reasonable information. Request
|
|
* forwarding with authentication spoofing.
|
|
*/
|
|
debug("Requesting X11 forwarding with authentication spoofing.");
|
|
x11_request_forwarding_with_spoofing(proto, data);
|
|
|
|
/* Read response from the server. */
|
|
type = packet_read(&plen);
|
|
if (type == SSH_SMSG_SUCCESS) {
|
|
forwarded = 1;
|
|
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. */
|
|
exit_status = client_loop(have_pty, tty_flag ? options.escape_char : -1);
|
|
|
|
/* Close the connection to the remote host. */
|
|
packet_close();
|
|
|
|
/* Exit with the status returned by the program on the remote side. */
|
|
exit(exit_status);
|
|
}
|