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openssh/clientloop.c
Damien Miller 54fd7cf2db - djm@cvs.openbsd.org 2007/09/04 03:21:03 
[clientloop.c monitor.c monitor_fdpass.c monitor_fdpass.h]
     [monitor_wrap.c ssh.c]
     make file descriptor passing code return an error rather than call fatal()
     when it encounters problems, and use this to make session multiplexing
     masters survive slaves failing to pass all stdio FDs; ok markus@
2007-09-17 12:04:08 +10:00

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/* $OpenBSD: clientloop.c,v 1.182 2007/09/04 03:21:03 djm Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, 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"
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/param.h>
#ifdef HAVE_SYS_STAT_H
# include <sys/stat.h>
#endif
#ifdef HAVE_SYS_TIME_H
# include <sys/time.h>
#endif
#include <sys/socket.h>
#include <ctype.h>
#include <errno.h>
#ifdef HAVE_PATHS_H
#include <paths.h>
#endif
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <pwd.h>
#include <unistd.h>
#include "xmalloc.h"
#include "ssh.h"
#include "ssh1.h"
#include "ssh2.h"
#include "packet.h"
#include "buffer.h"
#include "compat.h"
#include "channels.h"
#include "dispatch.h"
#include "key.h"
#include "cipher.h"
#include "kex.h"
#include "log.h"
#include "readconf.h"
#include "clientloop.h"
#include "sshconnect.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 volatile sig_atomic_t quit_pending; /* Set non-zero to quit the 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;
int want_x_fwd;
int want_agent_fwd;
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.
*/
/*ARGSUSED */
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.
*/
/*ARGSUSED */
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;
}
#define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1"
void
client_x11_get_proto(const char *display, const char *xauth_path,
u_int trusted, char **_proto, char **_data)
{
char cmd[1024];
char line[512];
char xdisplay[512];
static char proto[512], data[512];
FILE *f;
int got_data = 0, generated = 0, do_unlink = 0, i;
char *xauthdir, *xauthfile;
struct stat st;
xauthdir = xauthfile = NULL;
*_proto = proto;
*_data = data;
proto[0] = data[0] = '\0';
if (xauth_path == NULL ||(stat(xauth_path, &st) == -1)) {
debug("No xauth program.");
} else {
if (display == NULL) {
debug("x11_get_proto: DISPLAY not set");
return;
}
/*
* Handle FamilyLocal case where $DISPLAY does
* not match an authorization entry. For this we
* just try "xauth list unix:displaynum.screennum".
* XXX: "localhost" match to determine FamilyLocal
* is not perfect.
*/
if (strncmp(display, "localhost:", 10) == 0) {
snprintf(xdisplay, sizeof(xdisplay), "unix:%s",
display + 10);
display = xdisplay;
}
if (trusted == 0) {
xauthdir = xmalloc(MAXPATHLEN);
xauthfile = xmalloc(MAXPATHLEN);
strlcpy(xauthdir, "/tmp/ssh-XXXXXXXXXX", MAXPATHLEN);
if (mkdtemp(xauthdir) != NULL) {
do_unlink = 1;
snprintf(xauthfile, MAXPATHLEN, "%s/xauthfile",
xauthdir);
snprintf(cmd, sizeof(cmd),
"%s -f %s generate %s " SSH_X11_PROTO
" untrusted timeout 1200 2>" _PATH_DEVNULL,
xauth_path, xauthfile, display);
debug2("x11_get_proto: %s", cmd);
if (system(cmd) == 0)
generated = 1;
}
}
/*
* When in untrusted mode, we read the cookie only if it was
* successfully generated as an untrusted one in the step
* above.
*/
if (trusted || generated) {
snprintf(cmd, sizeof(cmd),
"%s %s%s list %s 2>" _PATH_DEVNULL,
xauth_path,
generated ? "-f " : "" ,
generated ? xauthfile : "",
display);
debug2("x11_get_proto: %s", cmd);
f = popen(cmd, "r");
if (f && fgets(line, sizeof(line), f) &&
sscanf(line, "%*s %511s %511s", proto, data) == 2)
got_data = 1;
if (f)
pclose(f);
} else
error("Warning: untrusted X11 forwarding setup failed: "
"xauth key data not generated");
}
if (do_unlink) {
unlink(xauthfile);
rmdir(xauthdir);
}
if (xauthdir)
xfree(xauthdir);
if (xauthfile)
xfree(xauthfile);
/*
* If we didn't get authentication data, just make up some
* data. The forwarding code will check the validity of the
* response anyway, and substitute this data. The X11
* server, however, will ignore this fake data and use
* whatever authentication mechanisms it was using otherwise
* for the local connection.
*/
if (!got_data) {
u_int32_t rnd = 0;
logit("Warning: No xauth data; "
"using fake authentication data for X11 forwarding.");
strlcpy(proto, SSH_X11_PROTO, sizeof proto);
for (i = 0; i < 16; i++) {
if (i % 4 == 0)
rnd = arc4random();
snprintf(data + 2 * i, sizeof data - 2 * i, "%02x",
rnd & 0xff);
rnd >>= 8;
}
}
}
/*
* 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((u_int)ws.ws_row);
packet_put_int((u_int)ws.ws_col);
packet_put_int((u_int)ws.ws_xpixel);
packet_put_int((u_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) {
logit("Timeout, server not responding.");
cleanup_exit(255);
}
packet_start(SSH2_MSG_GLOBAL_REQUEST);
packet_put_cstring("keepalive@openssh.com");
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;
const char *display;
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);
display = getenv("DISPLAY");
if (cctx->want_x_fwd && options.forward_x11 && display != NULL) {
char *proto, *data;
/* Get reasonable local authentication information. */
client_x11_get_proto(display, options.xauth_location,
options.forward_x11_trusted, &proto, &data);
/* Request forwarding with authentication spoofing. */
debug("Requesting X11 forwarding with authentication spoofing.");
x11_request_forwarding_with_spoofing(id, display, proto, data);
/* XXX wait for reply */
}
if (cctx->want_agent_fwd && options.forward_agent) {
debug("Requesting authentication agent forwarding.");
channel_request_start(id, "auth-agent-req@openssh.com", 0);
packet_send();
}
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, allowed, window, packetmax;
socklen_t addrlen;
struct sockaddr_storage addr;
struct confirm_ctx *cctx;
char *cmd;
u_int i, j, 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)) != SSHMUX_VER) {
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 == SSHCTL_MASTER_ASK ||
options.control_master == SSHCTL_MASTER_AUTO_ASK)
allowed = ask_permission("Allow shared connection "
"to %s? ", host);
/* continue below */
break;
case SSHMUX_COMMAND_TERMINATE:
if (options.control_master == SSHCTL_MASTER_ASK ||
options.control_master == SSHCTL_MASTER_AUTO_ASK)
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, SSHMUX_VER, &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, SSHMUX_VER, &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)) != SSHMUX_VER) {
error("%s: wrong client version %d", __func__, ver);
buffer_free(&m);
close(client_fd);
return;
}
cctx = xcalloc(1, sizeof(*cctx));
cctx->want_tty = (flags & SSHMUX_FLAG_TTY) != 0;
cctx->want_subsys = (flags & SSHMUX_FLAG_SUBSYS) != 0;
cctx->want_x_fwd = (flags & SSHMUX_FLAG_X11_FWD) != 0;
cctx->want_agent_fwd = (flags & SSHMUX_FLAG_AGENT_FWD) != 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 = xcalloc(env_len + 1, sizeof(*cctx->env));
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);
xfree(cmd);
/* Gather fds from client */
for(i = 0; i < 3; i++) {
if ((new_fd[i] = mm_receive_fd(client_fd)) == -1) {
error("%s: failed to receive fd %d from slave",
__func__, i);
for (j = 0; j < i; j++)
close(new_fd[j]);
for (j = 0; j < env_len; j++)
xfree(cctx->env[j]);
if (env_len > 0)
xfree(cctx->env);
xfree(cctx->term);
buffer_free(&cctx->cmd);
xfree(cctx);
return;
}
}
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, SSHMUX_VER, &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);
window = CHAN_SES_WINDOW_DEFAULT;
packetmax = CHAN_SES_PACKET_DEFAULT;
if (cctx->want_tty) {
window >>= 1;
packetmax >>= 1;
}
c = channel_new("session", SSH_CHANNEL_OPENING,
new_fd[0], new_fd[1], new_fd[2], window, packetmax,
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, *cancel_host;
int delete = 0;
int local = 0;
u_short cancel_port;
Forward fwd;
leave_raw_mode();
handler = signal(SIGINT, SIG_IGN);
cmd = s = read_passphrase("\r\nssh> ", RP_ECHO);
if (s == NULL)
goto out;
while (isspace(*s))
s++;
if (*s == '-')
s++; /* Skip cmdline '-', if any */
if (*s == '\0')
goto out;
if (*s == 'h' || *s == 'H' || *s == '?') {
logit("Commands:");
logit(" -L[bind_address:]port:host:hostport "
"Request local forward");
logit(" -R[bind_address:]port:host:hostport "
"Request remote forward");
logit(" -KR[bind_address:]port "
"Cancel remote forward");
if (!options.permit_local_command)
goto out;
logit(" !args "
"Execute local command");
goto out;
}
if (*s == '!' && options.permit_local_command) {
s++;
ssh_local_cmd(s);
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;
}
while (isspace(*++s))
;
if (delete) {
cancel_port = 0;
cancel_host = hpdelim(&s); /* may be NULL */
if (s != NULL) {
cancel_port = a2port(s);
cancel_host = cleanhostname(cancel_host);
} else {
cancel_port = a2port(cancel_host);
cancel_host = NULL;
}
if (cancel_port == 0) {
logit("Bad forwarding close port");
goto out;
}
channel_request_rforward_cancel(cancel_host, cancel_port);
} else {
if (!parse_forward(&fwd, s)) {
logit("Bad forwarding specification.");
goto out;
}
if (local) {
if (channel_setup_local_fwd_listener(fwd.listen_host,
fwd.listen_port, fwd.connect_host,
fwd.connect_port, options.gateway_ports) < 0) {
logit("Port forwarding failed.");
goto out;
}
} else {
if (channel_request_remote_forwarding(fwd.listen_host,
fwd.listen_port, fwd.connect_host,
fwd.connect_port) < 0) {
logit("Port forwarding failed.");
goto out;
}
}
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;
if (len <= 0)
return (0);
for (i = 0; i < (u_int)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;
default:
if (ch != escape_char) {
buffer_put_char(bin, escape_char);
bytes++;
}
/* Escaped characters fall through here */
break;
}
} else {
/*
* The previous character was not an escape char. Check if this
* is an escape.
*/
if (last_was_cr && ch == escape_char) {
/* It is. Set the flag and continue to next character. */
escape_pending = 1;
continue;
}
}
/*
* Normal character. Record whether it was a newline,
* and append it to the buffer.
*/
last_was_cr = (ch == '\r' || ch == '\n');
buffer_put_char(bin, ch);
bytes++;
}
return bytes;
}
static void
client_process_input(fd_set *readset)
{
int len;
char buf[8192];
/* Read input from stdin. */
if (FD_ISSET(fileno(stdin), readset)) {
/* Read as much as possible. */
len = read(fileno(stdin), buf, sizeof(buf));
if (len < 0 && (errno == EAGAIN || errno == EINTR))
return; /* we'll try again later */
if (len <= 0) {
/*
* Received EOF or error. They are treated
* similarly, except that an error message is printed
* if it was an error condition.
*/
if (len < 0) {
snprintf(buf, sizeof buf, "read: %.100s\r\n", strerror(errno));
buffer_append(&stderr_buffer, buf, strlen(buf));
}
/* Mark that we have seen EOF. */
stdin_eof = 1;
/*
* Send an EOF message to the server unless there is
* data in the buffer. If there is data in the
* buffer, no message will be sent now. Code
* elsewhere will send the EOF when the buffer
* becomes empty if stdin_eof is set.
*/
if (buffer_len(&stdin_buffer) == 0) {
packet_start(SSH_CMSG_EOF);
packet_send();
}
} else if (escape_char == SSH_ESCAPECHAR_NONE) {
/*
* Normal successful read, and no escape character.
* Just append the data to buffer.
*/
buffer_append(&stdin_buffer, buf, len);
} else {
/*
* Normal, successful read. But we have an escape character
* and have to process the characters one by one.
*/
if (process_escapes(&stdin_buffer, &stdout_buffer,
&stderr_buffer, buf, len) == -1)
return;
}
}
}
static void
client_process_output(fd_set *writeset)
{
int len;
char buf[100];
/* Write buffered output to stdout. */
if (FD_ISSET(fileno(stdout), writeset)) {
/* Write as much data as possible. */
len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
buffer_len(&stdout_buffer));
if (len <= 0) {
if (errno == EINTR || errno == EAGAIN)
len = 0;
else {
/*
* An error or EOF was encountered. Put an
* error message to stderr buffer.
*/
snprintf(buf, sizeof buf, "write stdout: %.50s\r\n", strerror(errno));
buffer_append(&stderr_buffer, buf, strlen(buf));
quit_pending = 1;
return;
}
}
/* Consume printed data from the buffer. */
buffer_consume(&stdout_buffer, len);
stdout_bytes += len;
}
/* Write buffered output to stderr. */
if (FD_ISSET(fileno(stderr), writeset)) {
/* Write as much data as possible. */
len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
buffer_len(&stderr_buffer));
if (len <= 0) {
if (errno == EINTR || errno == EAGAIN)
len = 0;
else {
/* EOF or error, but can't even print error message. */
quit_pending = 1;
return;
}
}
/* Consume printed characters from the buffer. */
buffer_consume(&stderr_buffer, len);
stderr_bytes += len;
}
}
/*
* Get packets from the connection input buffer, and process them as long as
* there are packets available.
*
* Any unknown packets received during the actual
* session cause the session to terminate. This is
* intended to make debugging easier since no
* confirmations are sent. Any compatible protocol
* extensions must be negotiated during the
* preparatory phase.
*/
static void
client_process_buffered_input_packets(void)
{
dispatch_run(DISPATCH_NONBLOCK, &quit_pending, compat20 ? xxx_kex : NULL);
}
/* scan buf[] for '~' before sending data to the peer */
static int
simple_escape_filter(Channel *c, char *buf, int len)
{
/* XXX we assume c->extended is writeable */
return process_escapes(&c->input, &c->output, &c->extended, buf, len);
}
static void
client_channel_closed(int id, void *arg)
{
channel_cancel_cleanup(id);
session_closed = 1;
leave_raw_mode();
}
/*
* Implements the interactive session with the server. This is called after
* the user has been authenticated, and a command has been started on the
* remote host. If escape_char != SSH_ESCAPECHAR_NONE, it is the character
* used as an escape character for terminating or suspending the session.
*/
int
client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
{
fd_set *readset = NULL, *writeset = NULL;
double start_time, total_time;
int max_fd = 0, max_fd2 = 0, len, rekeying = 0;
u_int nalloc = 0;
char buf[100];
debug("Entering interactive session.");
start_time = get_current_time();
/* Initialize variables. */
escape_pending = 0;
last_was_cr = 1;
exit_status = -1;
stdin_eof = 0;
buffer_high = 64 * 1024;
connection_in = packet_get_connection_in();
connection_out = packet_get_connection_out();
max_fd = MAX(connection_in, connection_out);
if (control_fd != -1)
max_fd = MAX(max_fd, control_fd);
if (!compat20) {
/* enable nonblocking unless tty */
if (!isatty(fileno(stdin)))
set_nonblock(fileno(stdin));
if (!isatty(fileno(stdout)))
set_nonblock(fileno(stdout));
if (!isatty(fileno(stderr)))
set_nonblock(fileno(stderr));
max_fd = MAX(max_fd, fileno(stdin));
max_fd = MAX(max_fd, fileno(stdout));
max_fd = MAX(max_fd, fileno(stderr));
}
stdin_bytes = 0;
stdout_bytes = 0;
stderr_bytes = 0;
quit_pending = 0;
escape_char = escape_char_arg;
/* Initialize buffers. */
buffer_init(&stdin_buffer);
buffer_init(&stdout_buffer);
buffer_init(&stderr_buffer);
client_init_dispatch();
/*
* Set signal handlers, (e.g. to restore non-blocking mode)
* but don't overwrite SIG_IGN, matches behaviour from rsh(1)
*/
if (signal(SIGHUP, SIG_IGN) != SIG_IGN)
signal(SIGHUP, signal_handler);
if (signal(SIGINT, SIG_IGN) != SIG_IGN)
signal(SIGINT, signal_handler);
if (signal(SIGQUIT, SIG_IGN) != SIG_IGN)
signal(SIGQUIT, signal_handler);
if (signal(SIGTERM, SIG_IGN) != SIG_IGN)
signal(SIGTERM, signal_handler);
signal(SIGWINCH, window_change_handler);
if (have_pty)
enter_raw_mode();
if (compat20) {
session_ident = ssh2_chan_id;
if (escape_char != SSH_ESCAPECHAR_NONE)
channel_register_filter(session_ident,
simple_escape_filter, NULL);
if (session_ident != -1)
channel_register_cleanup(session_ident,
client_channel_closed, 0);
} else {
/* Check if we should immediately send eof on stdin. */
client_check_initial_eof_on_stdin();
}
/* Main loop of the client for the interactive session mode. */
while (!quit_pending) {
/* Process buffered packets sent by the server. */
client_process_buffered_input_packets();
if (compat20 && session_closed && !channel_still_open())
break;
rekeying = (xxx_kex != NULL && !xxx_kex->done);
if (rekeying) {
debug("rekeying in progress");
} else {
/*
* Make packets of buffered stdin data, and buffer
* them for sending to the server.
*/
if (!compat20)
client_make_packets_from_stdin_data();
/*
* Make packets from buffered channel data, and
* enqueue them for sending to the server.
*/
if (packet_not_very_much_data_to_write())
channel_output_poll();
/*
* Check if the window size has changed, and buffer a
* message about it to the server if so.
*/
client_check_window_change();
if (quit_pending)
break;
}
/*
* Wait until we have something to do (something becomes
* available on one of the descriptors).
*/
max_fd2 = max_fd;
client_wait_until_can_do_something(&readset, &writeset,
&max_fd2, &nalloc, rekeying);
if (quit_pending)
break;
/* Do channel operations unless rekeying in progress. */
if (!rekeying) {
channel_after_select(readset, writeset);
if (need_rekeying || packet_need_rekeying()) {
debug("need rekeying");
xxx_kex->done = 0;
kex_send_kexinit(xxx_kex);
need_rekeying = 0;
}
}
/* Buffer input from the connection. */
client_process_net_input(readset);
/* Accept control connections. */
client_process_control(readset);
if (quit_pending)
break;
if (!compat20) {
/* Buffer data from stdin */
client_process_input(readset);
/*
* Process output to stdout and stderr. Output to
* the connection is processed elsewhere (above).
*/
client_process_output(writeset);
}
/* Send as much buffered packet data as possible to the sender. */
if (FD_ISSET(connection_out, writeset))
packet_write_poll();
}
if (readset)
xfree(readset);
if (writeset)
xfree(writeset);
/* Terminate the session. */
/* Stop watching for window change. */
signal(SIGWINCH, SIG_DFL);
channel_free_all();
if (have_pty)
leave_raw_mode();
/* restore blocking io */
if (!isatty(fileno(stdin)))
unset_nonblock(fileno(stdin));
if (!isatty(fileno(stdout)))
unset_nonblock(fileno(stdout));
if (!isatty(fileno(stderr)))
unset_nonblock(fileno(stderr));
/*
* If there was no shell or command requested, there will be no remote
* exit status to be returned. In that case, clear error code if the
* connection was deliberately terminated at this end.
*/
if (no_shell_flag && received_signal == SIGTERM) {
received_signal = 0;
exit_status = 0;
}
if (received_signal)
fatal("Killed by signal %d.", (int) received_signal);
/*
* In interactive mode (with pseudo tty) display a message indicating
* that the connection has been closed.
*/
if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) {
snprintf(buf, sizeof buf, "Connection to %.64s closed.\r\n", host);
buffer_append(&stderr_buffer, buf, strlen(buf));
}
/* Output any buffered data for stdout. */
while (buffer_len(&stdout_buffer) > 0) {
len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
buffer_len(&stdout_buffer));
if (len <= 0) {
error("Write failed flushing stdout buffer.");
break;
}
buffer_consume(&stdout_buffer, len);
stdout_bytes += len;
}
/* Output any buffered data for stderr. */
while (buffer_len(&stderr_buffer) > 0) {
len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
buffer_len(&stderr_buffer));
if (len <= 0) {
error("Write failed flushing stderr buffer.");
break;
}
buffer_consume(&stderr_buffer, len);
stderr_bytes += len;
}
/* Clear and free any buffers. */
memset(buf, 0, sizeof(buf));
buffer_free(&stdin_buffer);
buffer_free(&stdout_buffer);
buffer_free(&stderr_buffer);
/* Report bytes transferred, and transfer rates. */
total_time = get_current_time() - start_time;
debug("Transferred: stdin %lu, stdout %lu, stderr %lu bytes in %.1f seconds",
stdin_bytes, stdout_bytes, stderr_bytes, total_time);
if (total_time > 0)
debug("Bytes per second: stdin %.1f, stdout %.1f, stderr %.1f",
stdin_bytes / total_time, stdout_bytes / total_time,
stderr_bytes / total_time);
/* Return the exit status of the program. */
debug("Exit status %d", exit_status);
return exit_status;
}
/*********/
static void
client_input_stdout_data(int type, u_int32_t seq, void *ctxt)
{
u_int data_len;
char *data = packet_get_string(&data_len);
packet_check_eom();
buffer_append(&stdout_buffer, data, data_len);
memset(data, 0, data_len);
xfree(data);
}
static void
client_input_stderr_data(int type, u_int32_t seq, void *ctxt)
{
u_int data_len;
char *data = packet_get_string(&data_len);
packet_check_eom();
buffer_append(&stderr_buffer, data, data_len);
memset(data, 0, data_len);
xfree(data);
}
static void
client_input_exit_status(int type, u_int32_t seq, void *ctxt)
{
exit_status = packet_get_int();
packet_check_eom();
/* Acknowledge the exit. */
packet_start(SSH_CMSG_EXIT_CONFIRMATION);
packet_send();
/*
* Must wait for packet to be sent since we are
* exiting the loop.
*/
packet_write_wait();
/* Flag that we want to exit. */
quit_pending = 1;
}
static void
client_input_agent_open(int type, u_int32_t seq, void *ctxt)
{
Channel *c = NULL;
int remote_id, sock;
/* Read the remote channel number from the message. */
remote_id = packet_get_int();
packet_check_eom();
/*
* Get a connection to the local authentication agent (this may again
* get forwarded).
*/
sock = ssh_get_authentication_socket();
/*
* If we could not connect the agent, send an error message back to
* the server. This should never happen unless the agent dies,
* because authentication forwarding is only enabled if we have an
* agent.
*/
if (sock >= 0) {
c = channel_new("", SSH_CHANNEL_OPEN, sock, sock,
-1, 0, 0, 0, "authentication agent connection", 1);
c->remote_id = remote_id;
c->force_drain = 1;
}
if (c == NULL) {
packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
packet_put_int(remote_id);
} else {
/* Send a confirmation to the remote host. */
debug("Forwarding authentication connection.");
packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
packet_put_int(remote_id);
packet_put_int(c->self);
}
packet_send();
}
static Channel *
client_request_forwarded_tcpip(const char *request_type, int rchan)
{
Channel *c = NULL;
char *listen_address, *originator_address;
int listen_port, originator_port;
int sock;
/* Get rest of the packet */
listen_address = packet_get_string(NULL);
listen_port = packet_get_int();
originator_address = packet_get_string(NULL);
originator_port = packet_get_int();
packet_check_eom();
debug("client_request_forwarded_tcpip: listen %s port %d, originator %s port %d",
listen_address, listen_port, originator_address, originator_port);
sock = channel_connect_by_listen_address(listen_port);
if (sock < 0) {
xfree(originator_address);
xfree(listen_address);
return NULL;
}
c = channel_new("forwarded-tcpip",
SSH_CHANNEL_CONNECTING, sock, sock, -1,
CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0,
originator_address, 1);
xfree(originator_address);
xfree(listen_address);
return c;
}
static Channel *
client_request_x11(const char *request_type, int rchan)
{
Channel *c = NULL;
char *originator;
int originator_port;
int sock;
if (!options.forward_x11) {
error("Warning: ssh server tried X11 forwarding.");
error("Warning: this is probably a break-in attempt by a malicious server.");
return NULL;
}
originator = packet_get_string(NULL);
if (datafellows & SSH_BUG_X11FWD) {
debug2("buggy server: x11 request w/o originator_port");
originator_port = 0;
} else {
originator_port = packet_get_int();
}
packet_check_eom();
/* XXX check permission */
debug("client_request_x11: request from %s %d", originator,
originator_port);
xfree(originator);
sock = x11_connect_display();
if (sock < 0)
return NULL;
c = channel_new("x11",
SSH_CHANNEL_X11_OPEN, sock, sock, -1,
CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1);
c->force_drain = 1;
return c;
}
static Channel *
client_request_agent(const char *request_type, int rchan)
{
Channel *c = NULL;
int sock;
if (!options.forward_agent) {
error("Warning: ssh server tried agent forwarding.");
error("Warning: this is probably a break-in attempt by a malicious server.");
return NULL;
}
sock = ssh_get_authentication_socket();
if (sock < 0)
return NULL;
c = channel_new("authentication agent connection",
SSH_CHANNEL_OPEN, sock, sock, -1,
CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0,
"authentication agent connection", 1);
c->force_drain = 1;
return c;
}
int
client_request_tun_fwd(int tun_mode, int local_tun, int remote_tun)
{
Channel *c;
int fd;
if (tun_mode == SSH_TUNMODE_NO)
return 0;
if (!compat20) {
error("Tunnel forwarding is not support for protocol 1");
return -1;
}
debug("Requesting tun unit %d in mode %d", local_tun, tun_mode);
/* Open local tunnel device */
if ((fd = tun_open(local_tun, tun_mode)) == -1) {
error("Tunnel device open failed.");
return -1;
}
c = channel_new("tun", SSH_CHANNEL_OPENING, fd, fd, -1,
CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1);
c->datagram = 1;
#if defined(SSH_TUN_FILTER)
if (options.tun_open == SSH_TUNMODE_POINTOPOINT)
channel_register_filter(c->self, sys_tun_infilter,
sys_tun_outfilter);
#endif
packet_start(SSH2_MSG_CHANNEL_OPEN);
packet_put_cstring("tun@openssh.com");
packet_put_int(c->self);
packet_put_int(c->local_window_max);
packet_put_int(c->local_maxpacket);
packet_put_int(tun_mode);
packet_put_int(remote_tun);
packet_send();
return 0;
}
/* XXXX move to generic input handler */
static void
client_input_channel_open(int type, u_int32_t seq, void *ctxt)
{
Channel *c = NULL;
char *ctype;
int rchan;
u_int rmaxpack, rwindow, len;
ctype = packet_get_string(&len);
rchan = packet_get_int();
rwindow = packet_get_int();
rmaxpack = packet_get_int();
debug("client_input_channel_open: ctype %s rchan %d win %d max %d",
ctype, rchan, rwindow, rmaxpack);
if (strcmp(ctype, "forwarded-tcpip") == 0) {
c = client_request_forwarded_tcpip(ctype, rchan);
} else if (strcmp(ctype, "x11") == 0) {
c = client_request_x11(ctype, rchan);
} else if (strcmp(ctype, "auth-agent@openssh.com") == 0) {
c = client_request_agent(ctype, rchan);
}
/* XXX duplicate : */
if (c != NULL) {
debug("confirm %s", ctype);
c->remote_id = rchan;
c->remote_window = rwindow;
c->remote_maxpacket = rmaxpack;
if (c->type != SSH_CHANNEL_CONNECTING) {
packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
packet_put_int(c->remote_id);
packet_put_int(c->self);
packet_put_int(c->local_window);
packet_put_int(c->local_maxpacket);
packet_send();
}
} else {
debug("failure %s", ctype);
packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
packet_put_int(rchan);
packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
if (!(datafellows & SSH_BUG_OPENFAILURE)) {
packet_put_cstring("open failed");
packet_put_cstring("");
}
packet_send();
}
xfree(ctype);
}
static void
client_input_channel_req(int type, u_int32_t seq, void *ctxt)
{
Channel *c = NULL;
int exitval, id, reply, success = 0;
char *rtype;
id = packet_get_int();
rtype = packet_get_string(NULL);
reply = packet_get_char();
debug("client_input_channel_req: channel %d rtype %s reply %d",
id, rtype, reply);
if (id == -1) {
error("client_input_channel_req: request for channel -1");
} else if ((c = channel_lookup(id)) == NULL) {
error("client_input_channel_req: channel %d: unknown channel", id);
} else if (strcmp(rtype, "exit-status") == 0) {
exitval = packet_get_int();
if (id == session_ident) {
success = 1;
exit_status = exitval;
} else if (c->ctl_fd == -1) {
error("client_input_channel_req: unexpected channel %d",
session_ident);
} else {
atomicio(vwrite, c->ctl_fd, &exitval, sizeof(exitval));
success = 1;
}
packet_check_eom();
}
if (reply) {
packet_start(success ?
SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
packet_put_int(id);
packet_send();
}
xfree(rtype);
}
static void
client_input_global_request(int type, u_int32_t seq, void *ctxt)
{
char *rtype;
int want_reply;
int success = 0;
rtype = packet_get_string(NULL);
want_reply = packet_get_char();
debug("client_input_global_request: rtype %s want_reply %d",
rtype, want_reply);
if (want_reply) {
packet_start(success ?
SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE);
packet_send();
packet_write_wait();
}
xfree(rtype);
}
void
client_session2_setup(int id, int want_tty, int want_subsystem,
const char *term, struct termios *tiop, int in_fd, Buffer *cmd, char **env,
dispatch_fn *subsys_repl)
{
int len;
Channel *c = NULL;
debug2("%s: id %d", __func__, id);
if ((c = channel_lookup(id)) == NULL)
fatal("client_session2_setup: channel %d: unknown channel", id);
if (want_tty) {
struct winsize ws;
struct termios tio;
/* Store window size in the packet. */
if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0)
memset(&ws, 0, sizeof(ws));
channel_request_start(id, "pty-req", 0);
packet_put_cstring(term != NULL ? term : "");
packet_put_int((u_int)ws.ws_col);
packet_put_int((u_int)ws.ws_row);
packet_put_int((u_int)ws.ws_xpixel);
packet_put_int((u_int)ws.ws_ypixel);
tio = get_saved_tio();
tty_make_modes(-1, tiop != NULL ? tiop : &tio);
packet_send();
/* XXX wait for reply */
c->client_tty = 1;
}
/* Transfer any environment variables from client to server */
if (options.num_send_env != 0 && env != NULL) {
int i, j, matched;
char *name, *val;
debug("Sending environment.");
for (i = 0; env[i] != NULL; i++) {
/* Split */
name = xstrdup(env[i]);
if ((val = strchr(name, '=')) == NULL) {
xfree(name);
continue;
}
*val++ = '\0';
matched = 0;
for (j = 0; j < options.num_send_env; j++) {
if (match_pattern(name, options.send_env[j])) {
matched = 1;
break;
}
}
if (!matched) {
debug3("Ignored env %s", name);
xfree(name);
continue;
}
debug("Sending env %s = %s", name, val);
channel_request_start(id, "env", 0);
packet_put_cstring(name);
packet_put_cstring(val);
packet_send();
xfree(name);
}
}
len = buffer_len(cmd);
if (len > 0) {
if (len > 900)
len = 900;
if (want_subsystem) {
debug("Sending subsystem: %.*s", len, (u_char*)buffer_ptr(cmd));
channel_request_start(id, "subsystem", subsys_repl != NULL);
if (subsys_repl != NULL) {
/* register callback for reply */
/* XXX we assume that client_loop has already been called */
dispatch_set(SSH2_MSG_CHANNEL_FAILURE, subsys_repl);
dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, subsys_repl);
}
} else {
debug("Sending command: %.*s", len, (u_char*)buffer_ptr(cmd));
channel_request_start(id, "exec", 0);
}
packet_put_string(buffer_ptr(cmd), buffer_len(cmd));
packet_send();
} else {
channel_request_start(id, "shell", 0);
packet_send();
}
}
static void
client_init_dispatch_20(void)
{
dispatch_init(&dispatch_protocol_error);
dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open);
dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req);
dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request);
/* rekeying */
dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
/* global request reply messages */
dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply);
dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply);
}
static void
client_init_dispatch_13(void)
{
dispatch_init(NULL);
dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close);
dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation);
dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data);
dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open);
dispatch_set(SSH_SMSG_EXITSTATUS, &client_input_exit_status);
dispatch_set(SSH_SMSG_STDERR_DATA, &client_input_stderr_data);
dispatch_set(SSH_SMSG_STDOUT_DATA, &client_input_stdout_data);
dispatch_set(SSH_SMSG_AGENT_OPEN, options.forward_agent ?
&client_input_agent_open : &deny_input_open);
dispatch_set(SSH_SMSG_X11_OPEN, options.forward_x11 ?
&x11_input_open : &deny_input_open);
}
static void
client_init_dispatch_15(void)
{
client_init_dispatch_13();
dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, & channel_input_oclose);
}
static void
client_init_dispatch(void)
{
if (compat20)
client_init_dispatch_20();
else if (compat13)
client_init_dispatch_13();
else
client_init_dispatch_15();
}
/* client specific fatal cleanup */
void
cleanup_exit(int i)
{
leave_raw_mode();
leave_non_blocking();
if (options.control_path != NULL && control_fd != -1)
unlink(options.control_path);
_exit(i);
}
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