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clientloop.c
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/*
* Author: Tatu Ylonen <[email protected]>
* Copyright (c) 1995 Tatu Ylonen <[email protected]>, Espoo, Finland
* All rights reserved
* The main loop for the interactive session (client side).
*
* 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 Theo de Raadt. All rights reserved.
*
* 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.
*
*
* SSH2 support added by Markus Friedl.
* Copyright (c) 1999, 2000, 2001 Markus Friedl. All rights reserved.
*
* 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: clientloop.c,v 1.134 2004/11/07 00:01:46 djm Exp $");
#include "ssh.h"
#include "ssh1.h"
#include "ssh2.h"
#include "xmalloc.h"
#include "packet.h"
#include "buffer.h"
#include "compat.h"
#include "channels.h"
#include "dispatch.h"
#include "buffer.h"
#include "bufaux.h"
#include "key.h"
#include "kex.h"
#include "log.h"
#include "readconf.h"
#include "clientloop.h"
#include "authfd.h"
#include "atomicio.h"
#include "sshpty.h"
#include "misc.h"
#include "monitor_fdpass.h"
#include "match.h"
#include "msg.h"
/* import options */
extern Options options;
/* Flag indicating that stdin should be redirected from /dev/null. */
extern int stdin_null_flag;
/* Flag indicating that no shell has been requested */
extern int no_shell_flag;
/* Control socket */
extern int control_fd;
/*
* 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.
*/
extern char *host;
/*
* 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.
*/
static volatile sig_atomic_t received_window_change_signal = 0;
static volatile sig_atomic_t received_signal = 0;
/* Flag indicating whether the user\'s terminal is in non-blocking mode. */
static int in_non_blocking_mode = 0;
/* Common data for the client loop code. */
static int quit_pending; /* Set to non-zero to quit the client loop. */
static int escape_char; /* Escape character. */
static int escape_pending; /* Last character was the escape character */
static int last_was_cr; /* Last character was a newline. */
static int exit_status; /* Used to store the exit status of the command. */
static int stdin_eof; /* EOF has been encountered on standard error. */
static Buffer stdin_buffer; /* Buffer for stdin data. */
static Buffer stdout_buffer; /* Buffer for stdout data. */
static Buffer stderr_buffer; /* Buffer for stderr data. */
static u_long stdin_bytes, stdout_bytes, stderr_bytes;
static u_int buffer_high;/* Soft max buffer size. */
static int connection_in; /* Connection to server (input). */
static int connection_out; /* Connection to server (output). */
static int need_rekeying; /* Set to non-zero if rekeying is requested. */
static int session_closed = 0; /* In SSH2: login session closed. */
static int server_alive_timeouts = 0;
static void client_init_dispatch(void);
int session_ident = -1;
struct confirm_ctx {
int want_tty;
int want_subsys;
Buffer cmd;
char *term;
struct termios tio;
char **env;
};
/*XXX*/
extern Kex *xxx_kex;
void ssh_process_session2_setup(int, int, int, Buffer *);
/* Restores stdin to blocking mode. */
static void
leave_non_blocking(void)
{
if (in_non_blocking_mode) {
unset_nonblock(fileno(stdin));
in_non_blocking_mode = 0;
}
}
/* Puts stdin terminal in non-blocking mode. */
static void
enter_non_blocking(void)
{
in_non_blocking_mode = 1;
set_nonblock(fileno(stdin));
}
/*
* Signal handler for the window change signal (SIGWINCH). This just sets a
* flag indicating that the window has changed.
*/
static void
window_change_handler(int sig)
{
received_window_change_signal = 1;
signal(SIGWINCH, window_change_handler);
}
/*
* Signal handler for signals that cause the program to terminate. These
* signals must be trapped to restore terminal modes.
*/
static void
signal_handler(int sig)
{
received_signal = sig;
quit_pending = 1;
}
/*
* Returns current time in seconds from Jan 1, 1970 with the maximum
* available resolution.
*/
static double
get_current_time(void)
{
struct timeval tv;
gettimeofday(&tv, NULL);
return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0;
}
/*
* This is called when the interactive is entered. This checks if there is
* an EOF coming on stdin. We must check this explicitly, as select() does
* not appear to wake up when redirecting from /dev/null.
*/
static void
client_check_initial_eof_on_stdin(void)
{
int len;
char buf[1];
/*
* If standard input is to be "redirected from /dev/null", we simply
* mark that we have seen an EOF and send an EOF message to the
* server. Otherwise, we try to read a single character; it appears
* that for some files, such /dev/null, select() never wakes up for
* read for this descriptor, which means that we never get EOF. This
* way we will get the EOF if stdin comes from /dev/null or similar.
*/
if (stdin_null_flag) {
/* Fake EOF on stdin. */
debug("Sending eof.");
stdin_eof = 1;
packet_start(SSH_CMSG_EOF);
packet_send();
} else {
enter_non_blocking();
/* Check for immediate EOF on stdin. */
len = read(fileno(stdin), buf, 1);
if (len == 0) {
/* EOF. Record that we have seen it and send EOF to server. */
debug("Sending eof.");
stdin_eof = 1;
packet_start(SSH_CMSG_EOF);
packet_send();
} else if (len > 0) {
/*
* Got data. We must store the data in the buffer,
* and also process it as an escape character if
* appropriate.
*/
if ((u_char) buf[0] == escape_char)
escape_pending = 1;
else
buffer_append(&stdin_buffer, buf, 1);
}
leave_non_blocking();
}
}
/*
* Make packets from buffered stdin data, and buffer them for sending to the
* connection.
*/
static void
client_make_packets_from_stdin_data(void)
{
u_int len;
/* Send buffered stdin data to the server. */
while (buffer_len(&stdin_buffer) > 0 &&
packet_not_very_much_data_to_write()) {
len = buffer_len(&stdin_buffer);
/* Keep the packets at reasonable size. */
if (len > packet_get_maxsize())
len = packet_get_maxsize();
packet_start(SSH_CMSG_STDIN_DATA);
packet_put_string(buffer_ptr(&stdin_buffer), len);
packet_send();
buffer_consume(&stdin_buffer, len);
stdin_bytes += len;
/* If we have a pending EOF, send it now. */
if (stdin_eof && buffer_len(&stdin_buffer) == 0) {
packet_start(SSH_CMSG_EOF);
packet_send();
}
}
}
/*
* Checks if the client window has changed, and sends a packet about it to
* the server if so. The actual change is detected elsewhere (by a software
* interrupt on Unix); this just checks the flag and sends a message if
* appropriate.
*/
static void
client_check_window_change(void)
{
struct winsize ws;
if (! received_window_change_signal)
return;
/** XXX race */
received_window_change_signal = 0;
debug2("client_check_window_change: changed");
if (compat20) {
channel_send_window_changes();
} else {
if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
return;
packet_start(SSH_CMSG_WINDOW_SIZE);
packet_put_int(ws.ws_row);
packet_put_int(ws.ws_col);
packet_put_int(ws.ws_xpixel);
packet_put_int(ws.ws_ypixel);
packet_send();
}
}
static void
client_global_request_reply(int type, u_int32_t seq, void *ctxt)
{
server_alive_timeouts = 0;
client_global_request_reply_fwd(type, seq, ctxt);
}
static void
server_alive_check(void)
{
if (++server_alive_timeouts > options.server_alive_count_max)
packet_disconnect("Timeout, server not responding.");
packet_start(SSH2_MSG_GLOBAL_REQUEST);
packet_put_cstring("[email protected]");
packet_put_char(1); /* boolean: want reply */
packet_send();
}
/*
* Waits until the client can do something (some data becomes available on
* one of the file descriptors).
*/
static void
client_wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp,
int *maxfdp, u_int *nallocp, int rekeying)
{
struct timeval tv, *tvp;
int ret;
/* Add any selections by the channel mechanism. */
channel_prepare_select(readsetp, writesetp, maxfdp, nallocp, rekeying);
if (!compat20) {
/* Read from the connection, unless our buffers are full. */
if (buffer_len(&stdout_buffer) < buffer_high &&
buffer_len(&stderr_buffer) < buffer_high &&
channel_not_very_much_buffered_data())
FD_SET(connection_in, *readsetp);
/*
* Read from stdin, unless we have seen EOF or have very much
* buffered data to send to the server.
*/
if (!stdin_eof && packet_not_very_much_data_to_write())
FD_SET(fileno(stdin), *readsetp);
/* Select stdout/stderr if have data in buffer. */
if (buffer_len(&stdout_buffer) > 0)
FD_SET(fileno(stdout), *writesetp);
if (buffer_len(&stderr_buffer) > 0)
FD_SET(fileno(stderr), *writesetp);
} else {
/* channel_prepare_select could have closed the last channel */
if (session_closed && !channel_still_open() &&
!packet_have_data_to_write()) {
/* clear mask since we did not call select() */
memset(*readsetp, 0, *nallocp);
memset(*writesetp, 0, *nallocp);
return;
} else {
FD_SET(connection_in, *readsetp);
}
}
/* Select server connection if have data to write to the server. */
if (packet_have_data_to_write())
FD_SET(connection_out, *writesetp);
if (control_fd != -1)
FD_SET(control_fd, *readsetp);
/*
* Wait for something to happen. This will suspend the process until
* some selected descriptor can be read, written, or has some other
* event pending.
*/
if (options.server_alive_interval == 0 || !compat20)
tvp = NULL;
else {
tv.tv_sec = options.server_alive_interval;
tv.tv_usec = 0;
tvp = &tv;
}
ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp);
if (ret < 0) {
char buf[100];
/*
* We have to clear the select masks, because we return.
* We have to return, because the mainloop checks for the flags
* set by the signal handlers.
*/
memset(*readsetp, 0, *nallocp);
memset(*writesetp, 0, *nallocp);
if (errno == EINTR)
return;
/* Note: we might still have data in the buffers. */
snprintf(buf, sizeof buf, "select: %s\r\n", strerror(errno));
buffer_append(&stderr_buffer, buf, strlen(buf));
quit_pending = 1;
} else if (ret == 0)
server_alive_check();
}
static void
client_suspend_self(Buffer *bin, Buffer *bout, Buffer *berr)
{
/* Flush stdout and stderr buffers. */
if (buffer_len(bout) > 0)
atomicio(vwrite, fileno(stdout), buffer_ptr(bout), buffer_len(bout));
if (buffer_len(berr) > 0)
atomicio(vwrite, fileno(stderr), buffer_ptr(berr), buffer_len(berr));
leave_raw_mode();
/*
* Free (and clear) the buffer to reduce the amount of data that gets
* written to swap.
*/
buffer_free(bin);
buffer_free(bout);
buffer_free(berr);
/* Send the suspend signal to the program itself. */
kill(getpid(), SIGTSTP);
/* Reset window sizes in case they have changed */
received_window_change_signal = 1;
/* OK, we have been continued by the user. Reinitialize buffers. */
buffer_init(bin);
buffer_init(bout);
buffer_init(berr);
enter_raw_mode();
}
static void
client_process_net_input(fd_set * readset)
{
int len;
char buf[8192];
/*
* Read input from the server, and add any such data to the buffer of
* the packet subsystem.
*/
if (FD_ISSET(connection_in, readset)) {
/* Read as much as possible. */
len = read(connection_in, buf, sizeof(buf));
if (len == 0) {
/* Received EOF. The remote host has closed the connection. */
snprintf(buf, sizeof buf, "Connection to %.300s closed by remote host.\r\n",
host);
buffer_append(&stderr_buffer, buf, strlen(buf));
quit_pending = 1;
return;
}
/*
* There is a kernel bug on Solaris that causes select to
* sometimes wake up even though there is no data available.
*/
if (len < 0 && (errno == EAGAIN || errno == EINTR))
len = 0;
if (len < 0) {
/* An error has encountered. Perhaps there is a network problem. */
snprintf(buf, sizeof buf, "Read from remote host %.300s: %.100s\r\n",
host, strerror(errno));
buffer_append(&stderr_buffer, buf, strlen(buf));
quit_pending = 1;
return;
}
packet_process_incoming(buf, len);
}
}
static void
client_subsystem_reply(int type, u_int32_t seq, void *ctxt)
{
int id;
Channel *c;
id = packet_get_int();
packet_check_eom();
if ((c = channel_lookup(id)) == NULL) {
error("%s: no channel for id %d", __func__, id);
return;
}
if (type == SSH2_MSG_CHANNEL_SUCCESS)
debug2("Request suceeded on channel %d", id);
else if (type == SSH2_MSG_CHANNEL_FAILURE) {
error("Request failed on channel %d", id);
channel_free(c);
}
}
static void
client_extra_session2_setup(int id, void *arg)
{
struct confirm_ctx *cctx = arg;
Channel *c;
int i;
if (cctx == NULL)
fatal("%s: cctx == NULL", __func__);
if ((c = channel_lookup(id)) == NULL)
fatal("%s: no channel for id %d", __func__, id);
client_session2_setup(id, cctx->want_tty, cctx->want_subsys,
cctx->term, &cctx->tio, c->rfd, &cctx->cmd, cctx->env,
client_subsystem_reply);
c->confirm_ctx = NULL;
buffer_free(&cctx->cmd);
xfree(cctx->term);
if (cctx->env != NULL) {
for (i = 0; cctx->env[i] != NULL; i++)
xfree(cctx->env[i]);
xfree(cctx->env);
}
xfree(cctx);
}
static void
client_process_control(fd_set * readset)
{
Buffer m;
Channel *c;
int client_fd, new_fd[3], ver, i, allowed;
socklen_t addrlen;
struct sockaddr_storage addr;
struct confirm_ctx *cctx;
char *cmd;
u_int len, env_len, command, flags;
uid_t euid;
gid_t egid;
/*
* Accept connection on control socket
*/
if (control_fd == -1 || !FD_ISSET(control_fd, readset))
return;
memset(&addr, 0, sizeof(addr));
addrlen = sizeof(addr);
if ((client_fd = accept(control_fd,
(struct sockaddr*)&addr, &addrlen)) == -1) {
error("%s accept: %s", __func__, strerror(errno));
return;
}
if (getpeereid(client_fd, &euid, &egid) < 0) {
error("%s getpeereid failed: %s", __func__, strerror(errno));
close(client_fd);
return;
}
if ((euid != 0) && (getuid() != euid)) {
error("control mode uid mismatch: peer euid %u != uid %u",
(u_int) euid, (u_int) getuid());
close(client_fd);
return;
}
unset_nonblock(client_fd);
/* Read command */
buffer_init(&m);
if (ssh_msg_recv(client_fd, &m) == -1) {
error("%s: client msg_recv failed", __func__);
close(client_fd);
buffer_free(&m);
return;
}
if ((ver = buffer_get_char(&m)) != 1) {
error("%s: wrong client version %d", __func__, ver);
buffer_free(&m);
close(client_fd);
return;
}
allowed = 1;
command = buffer_get_int(&m);
flags = buffer_get_int(&m);
buffer_clear(&m);
switch (command) {
case SSHMUX_COMMAND_OPEN:
if (options.control_master == 2)
allowed = ask_permission("Allow shared connection "
"to %s? ", host);
/* continue below */
break;
case SSHMUX_COMMAND_TERMINATE:
if (options.control_master == 2)
allowed = ask_permission("Terminate shared connection "
"to %s? ", host);
if (allowed)
quit_pending = 1;
/* FALLTHROUGH */
case SSHMUX_COMMAND_ALIVE_CHECK:
/* Reply for SSHMUX_COMMAND_TERMINATE and ALIVE_CHECK */
buffer_clear(&m);
buffer_put_int(&m, allowed);
buffer_put_int(&m, getpid());
if (ssh_msg_send(client_fd, /* version */1, &m) == -1) {
error("%s: client msg_send failed", __func__);
close(client_fd);
buffer_free(&m);
return;
}
buffer_free(&m);
close(client_fd);
return;
default:
error("Unsupported command %d", command);
buffer_free(&m);
close(client_fd);
return;
}
/* Reply for SSHMUX_COMMAND_OPEN */
buffer_clear(&m);
buffer_put_int(&m, allowed);
buffer_put_int(&m, getpid());
if (ssh_msg_send(client_fd, /* version */1, &m) == -1) {
error("%s: client msg_send failed", __func__);
close(client_fd);
buffer_free(&m);
return;
}
if (!allowed) {
error("Refused control connection");
close(client_fd);
buffer_free(&m);
return;
}
buffer_clear(&m);
if (ssh_msg_recv(client_fd, &m) == -1) {
error("%s: client msg_recv failed", __func__);
close(client_fd);
buffer_free(&m);
return;
}
if ((ver = buffer_get_char(&m)) != 1) {
error("%s: wrong client version %d", __func__, ver);
buffer_free(&m);
close(client_fd);
return;
}
cctx = xmalloc(sizeof(*cctx));
memset(cctx, 0, sizeof(*cctx));
cctx->want_tty = (flags & SSHMUX_FLAG_TTY) != 0;
cctx->want_subsys = (flags & SSHMUX_FLAG_SUBSYS) != 0;
cctx->term = buffer_get_string(&m, &len);
cmd = buffer_get_string(&m, &len);
buffer_init(&cctx->cmd);
buffer_append(&cctx->cmd, cmd, strlen(cmd));
env_len = buffer_get_int(&m);
env_len = MIN(env_len, 4096);
debug3("%s: receiving %d env vars", __func__, env_len);
if (env_len != 0) {
cctx->env = xmalloc(sizeof(*cctx->env) * (env_len + 1));
for (i = 0; i < env_len; i++)
cctx->env[i] = buffer_get_string(&m, &len);
cctx->env[i] = NULL;
}
debug2("%s: accepted tty %d, subsys %d, cmd %s", __func__,
cctx->want_tty, cctx->want_subsys, cmd);
/* Gather fds from client */
new_fd[0] = mm_receive_fd(client_fd);
new_fd[1] = mm_receive_fd(client_fd);
new_fd[2] = mm_receive_fd(client_fd);
debug2("%s: got fds stdin %d, stdout %d, stderr %d", __func__,
new_fd[0], new_fd[1], new_fd[2]);
/* Try to pick up ttymodes from client before it goes raw */
if (cctx->want_tty && tcgetattr(new_fd[0], &cctx->tio) == -1)
error("%s: tcgetattr: %s", __func__, strerror(errno));
/* This roundtrip is just for synchronisation of ttymodes */
buffer_clear(&m);
if (ssh_msg_send(client_fd, /* version */1, &m) == -1) {
error("%s: client msg_send failed", __func__);
close(client_fd);
close(new_fd[0]);
close(new_fd[1]);
close(new_fd[2]);
buffer_free(&m);
xfree(cctx->term);
if (env_len != 0) {
for (i = 0; i < env_len; i++)
xfree(cctx->env[i]);
xfree(cctx->env);
}
return;
}
buffer_free(&m);
/* enable nonblocking unless tty */
if (!isatty(new_fd[0]))
set_nonblock(new_fd[0]);
if (!isatty(new_fd[1]))
set_nonblock(new_fd[1]);
if (!isatty(new_fd[2]))
set_nonblock(new_fd[2]);
set_nonblock(client_fd);
c = channel_new("session", SSH_CHANNEL_OPENING,
new_fd[0], new_fd[1], new_fd[2],
CHAN_SES_WINDOW_DEFAULT, CHAN_SES_PACKET_DEFAULT,
CHAN_EXTENDED_WRITE, "client-session", /*nonblock*/0);
/* XXX */
c->ctl_fd = client_fd;
debug3("%s: channel_new: %d", __func__, c->self);
channel_send_open(c->self);
channel_register_confirm(c->self, client_extra_session2_setup, cctx);
}
static void
process_cmdline(void)
{
void (*handler)(int);
char *s, *cmd;
u_short fwd_port, fwd_host_port;
char buf[1024], sfwd_port[6], sfwd_host_port[6];
int delete = 0;
int local = 0;
leave_raw_mode();
handler = signal(SIGINT, SIG_IGN);
cmd = s = read_passphrase("\r\nssh> ", RP_ECHO);
if (s == NULL)
goto out;
while (*s && isspace(*s))
s++;
if (*s == '-')
s++; /* Skip cmdline '-', if any */
if (*s == '\0')
goto out;
if (*s == 'h' || *s == 'H' || *s == '?') {
logit("Commands:");
logit(" -Lport:host:hostport Request local forward");
logit(" -Rport:host:hostport Request remote forward");
logit(" -KRhostport Cancel remote forward");
goto out;
}
if (*s == 'K') {
delete = 1;
s++;
}
if (*s != 'L' && *s != 'R') {
logit("Invalid command.");
goto out;
}
if (*s == 'L')
local = 1;
if (local && delete) {
logit("Not supported.");
goto out;
}
if ((!local || delete) && !compat20) {
logit("Not supported for SSH protocol version 1.");
goto out;
}
s++;
while (*s && isspace(*s))
s++;
if (delete) {
if (sscanf(s, "%5[0-9]", sfwd_host_port) != 1) {
logit("Bad forwarding specification.");
goto out;
}
if ((fwd_host_port = a2port(sfwd_host_port)) == 0) {
logit("Bad forwarding port(s).");
goto out;
}
channel_request_rforward_cancel(fwd_host_port);
} else {
if (sscanf(s, "%5[0-9]:%255[^:]:%5[0-9]",
sfwd_port, buf, sfwd_host_port) != 3 &&
sscanf(s, "%5[0-9]/%255[^/]/%5[0-9]",
sfwd_port, buf, sfwd_host_port) != 3) {
logit("Bad forwarding specification.");
goto out;
}
if ((fwd_port = a2port(sfwd_port)) == 0 ||
(fwd_host_port = a2port(sfwd_host_port)) == 0) {
logit("Bad forwarding port(s).");
goto out;
}
if (local) {
if (channel_setup_local_fwd_listener(fwd_port, buf,
fwd_host_port, options.gateway_ports) < 0) {
logit("Port forwarding failed.");
goto out;
}
} else
channel_request_remote_forwarding(fwd_port, buf,
fwd_host_port);
logit("Forwarding port.");
}
out:
signal(SIGINT, handler);
enter_raw_mode();
if (cmd)
xfree(cmd);
}
/* process the characters one by one */
static int
process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len)
{
char string[1024];
pid_t pid;
int bytes = 0;
u_int i;
u_char ch;
char *s;
for (i = 0; i < len; i++) {
/* Get one character at a time. */
ch = buf[i];
if (escape_pending) {
/* We have previously seen an escape character. */
/* Clear the flag now. */
escape_pending = 0;
/* Process the escaped character. */
switch (ch) {
case '.':
/* Terminate the connection. */
snprintf(string, sizeof string, "%c.\r\n", escape_char);
buffer_append(berr, string, strlen(string));
quit_pending = 1;
return -1;
case 'Z' - 64:
/* Suspend the program. */
/* Print a message to that effect to the user. */
snprintf(string, sizeof string, "%c^Z [suspend ssh]\r\n", escape_char);
buffer_append(berr, string, strlen(string));
/* Restore terminal modes and suspend. */
client_suspend_self(bin, bout, berr);
/* We have been continued. */
continue;
case 'B':
if (compat20) {
snprintf(string, sizeof string,
"%cB\r\n", escape_char);
buffer_append(berr, string,
strlen(string));
channel_request_start(session_ident,
"break", 0);
packet_put_int(1000);
packet_send();
}
continue;
case 'R':
if (compat20) {
if (datafellows & SSH_BUG_NOREKEY)
logit("Server does not support re-keying");
else
need_rekeying = 1;
}
continue;
case '&':
/*
* Detach the program (continue to serve connections,
* but put in background and no more new connections).
*/
/* Restore tty modes. */
leave_raw_mode();
/* Stop listening for new connections. */
channel_stop_listening();
snprintf(string, sizeof string,
"%c& [backgrounded]\n", escape_char);
buffer_append(berr, string, strlen(string));
/* Fork into background. */
pid = fork();
if (pid < 0) {
error("fork: %.100s", strerror(errno));
continue;
}
if (pid != 0) { /* This is the parent. */
/* The parent just exits. */
exit(0);
}
/* The child continues serving connections. */
if (compat20) {
buffer_append(bin, "\004", 1);
/* fake EOF on stdin */
return -1;
} else if (!stdin_eof) {
/*
* Sending SSH_CMSG_EOF alone does not always appear
* to be enough. So we try to send an EOF character
* first.
*/
packet_start(SSH_CMSG_STDIN_DATA);
packet_put_string("\004", 1);
packet_send();
/* Close stdin. */
stdin_eof = 1;
if (buffer_len(bin) == 0) {
packet_start(SSH_CMSG_EOF);
packet_send();
}
}
continue;
case '?':
snprintf(string, sizeof string,
"%c?\r\n\
Supported escape sequences:\r\n\
%c. - terminate connection\r\n\
%cB - send a BREAK to the remote system\r\n\
%cC - open a command line\r\n\
%cR - Request rekey (SSH protocol 2 only)\r\n\
%c^Z - suspend ssh\r\n\
%c# - list forwarded connections\r\n\
%c& - background ssh (when waiting for connections to terminate)\r\n\
%c? - this message\r\n\
%c%c - send the escape character by typing it twice\r\n\
(Note that escapes are only recognized immediately after newline.)\r\n",
escape_char, escape_char, escape_char, escape_char,
escape_char, escape_char, escape_char, escape_char,
escape_char, escape_char, escape_char);
buffer_append(berr, string, strlen(string));
continue;
case '#':
snprintf(string, sizeof string, "%c#\r\n", escape_char);
buffer_append(berr, string, strlen(string));
s = channel_open_message();
buffer_append(berr, s, strlen(s));
xfree(s);
continue;
case 'C':
process_cmdline();
continue;