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sonic-openssh
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sonic-openssh/clientloop.c

2015 строки
54 KiB
C
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/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
* All rights reserved
* 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 1.149 2005/12/30 15:56:37 reyk 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 "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 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;
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.
*/
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;
}
#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;
}
}
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);
}
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(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("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;
socklen_t addrlen;
struct sockaddr_storage addr;
struct confirm_ctx *cctx;
char *cmd;
u_int i, 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 = 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->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 = 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, 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);
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, *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 (*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");
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;
}
s++;
while (*s && isspace(*s))
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 {
channel_request_remote_forwarding(fwd.listen_host,
fwd.listen_port, fwd.connect_host,
fwd.connect_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;
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;
}
/* 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(ws.ws_col);
packet_put_int(ws.ws_row);
packet_put_int(ws.ws_xpixel);
packet_put_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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