939 lines
27 KiB
C
939 lines
27 KiB
C
/* $NetBSD: serverloop.c,v 1.1.1.2 2001/01/14 04:50:38 itojun Exp $ */
|
|
|
|
/*
|
|
* Author: Tatu Ylonen <ylo@cs.hut.fi>
|
|
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
|
|
* All rights reserved
|
|
* Server main loop for handling the interactive session.
|
|
*
|
|
* 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".
|
|
*
|
|
* SSH2 support by Markus Friedl.
|
|
* Copyright (c) 2000 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.
|
|
*/
|
|
|
|
/* from OpenBSD: serverloop.c,v 1.39 2000/12/27 14:19:21 markus Exp */
|
|
|
|
#include <sys/cdefs.h>
|
|
#ifndef lint
|
|
__RCSID("$NetBSD: serverloop.c,v 1.1.1.2 2001/01/14 04:50:38 itojun Exp $");
|
|
#endif
|
|
|
|
#include "includes.h"
|
|
|
|
#include "xmalloc.h"
|
|
#include "ssh.h"
|
|
#include "packet.h"
|
|
#include "buffer.h"
|
|
#include "servconf.h"
|
|
#include "pty.h"
|
|
#include "channels.h"
|
|
|
|
#include "compat.h"
|
|
#include "ssh2.h"
|
|
#include "session.h"
|
|
#include "dispatch.h"
|
|
#include "auth-options.h"
|
|
#include "auth.h"
|
|
|
|
extern ServerOptions options;
|
|
|
|
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 int fdin; /* Descriptor for stdin (for writing) */
|
|
static int fdout; /* Descriptor for stdout (for reading);
|
|
May be same number as fdin. */
|
|
static int fderr; /* Descriptor for stderr. May be -1. */
|
|
static long stdin_bytes = 0; /* Number of bytes written to stdin. */
|
|
static long stdout_bytes = 0; /* Number of stdout bytes sent to client. */
|
|
static long stderr_bytes = 0; /* Number of stderr bytes sent to client. */
|
|
static long fdout_bytes = 0; /* Number of stdout bytes read from program. */
|
|
static int stdin_eof = 0; /* EOF message received from client. */
|
|
static int fdout_eof = 0; /* EOF encountered reading from fdout. */
|
|
static int fderr_eof = 0; /* EOF encountered readung from fderr. */
|
|
static int connection_in; /* Connection to client (input). */
|
|
static int connection_out; /* Connection to client (output). */
|
|
static u_int buffer_high;/* "Soft" max buffer size. */
|
|
static int max_fd; /* Max file descriptor number for select(). */
|
|
|
|
/*
|
|
* This SIGCHLD kludge is used to detect when the child exits. The server
|
|
* will exit after that, as soon as forwarded connections have terminated.
|
|
*/
|
|
|
|
static pid_t child_pid; /* Pid of the child. */
|
|
static volatile int child_terminated; /* The child has terminated. */
|
|
static volatile int child_wait_status; /* Status from wait(). */
|
|
|
|
void server_init_dispatch(void);
|
|
|
|
static void
|
|
sigchld_handler(int sig)
|
|
{
|
|
int save_errno = errno;
|
|
pid_t wait_pid;
|
|
|
|
debug("Received SIGCHLD.");
|
|
wait_pid = wait((int *) &child_wait_status);
|
|
if (wait_pid != -1) {
|
|
if (wait_pid != child_pid)
|
|
error("Strange, got SIGCHLD and wait returned pid %d but child is %d",
|
|
wait_pid, child_pid);
|
|
if (WIFEXITED(child_wait_status) ||
|
|
WIFSIGNALED(child_wait_status))
|
|
child_terminated = 1;
|
|
}
|
|
signal(SIGCHLD, sigchld_handler);
|
|
errno = save_errno;
|
|
}
|
|
static void
|
|
sigchld_handler2(int sig)
|
|
{
|
|
int save_errno = errno;
|
|
debug("Received SIGCHLD.");
|
|
child_terminated = 1;
|
|
signal(SIGCHLD, sigchld_handler2);
|
|
errno = save_errno;
|
|
}
|
|
|
|
/*
|
|
* Make packets from buffered stderr data, and buffer it for sending
|
|
* to the client.
|
|
*/
|
|
static void
|
|
make_packets_from_stderr_data(void)
|
|
{
|
|
int len;
|
|
|
|
/* Send buffered stderr data to the client. */
|
|
while (buffer_len(&stderr_buffer) > 0 &&
|
|
packet_not_very_much_data_to_write()) {
|
|
len = buffer_len(&stderr_buffer);
|
|
if (packet_is_interactive()) {
|
|
if (len > 512)
|
|
len = 512;
|
|
} else {
|
|
/* Keep the packets at reasonable size. */
|
|
if (len > packet_get_maxsize())
|
|
len = packet_get_maxsize();
|
|
}
|
|
packet_start(SSH_SMSG_STDERR_DATA);
|
|
packet_put_string(buffer_ptr(&stderr_buffer), len);
|
|
packet_send();
|
|
buffer_consume(&stderr_buffer, len);
|
|
stderr_bytes += len;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Make packets from buffered stdout data, and buffer it for sending to the
|
|
* client.
|
|
*/
|
|
static void
|
|
make_packets_from_stdout_data(void)
|
|
{
|
|
int len;
|
|
|
|
/* Send buffered stdout data to the client. */
|
|
while (buffer_len(&stdout_buffer) > 0 &&
|
|
packet_not_very_much_data_to_write()) {
|
|
len = buffer_len(&stdout_buffer);
|
|
if (packet_is_interactive()) {
|
|
if (len > 512)
|
|
len = 512;
|
|
} else {
|
|
/* Keep the packets at reasonable size. */
|
|
if (len > packet_get_maxsize())
|
|
len = packet_get_maxsize();
|
|
}
|
|
packet_start(SSH_SMSG_STDOUT_DATA);
|
|
packet_put_string(buffer_ptr(&stdout_buffer), len);
|
|
packet_send();
|
|
buffer_consume(&stdout_buffer, len);
|
|
stdout_bytes += len;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Sleep in select() until we can do something. This will initialize the
|
|
* select masks. Upon return, the masks will indicate which descriptors
|
|
* have data or can accept data. Optionally, a maximum time can be specified
|
|
* for the duration of the wait (0 = infinite).
|
|
*/
|
|
static void
|
|
wait_until_can_do_something(fd_set * readset, fd_set * writeset,
|
|
u_int max_time_milliseconds)
|
|
{
|
|
struct timeval tv, *tvp;
|
|
int ret;
|
|
|
|
/* When select fails we restart from here. */
|
|
retry_select:
|
|
|
|
/* Initialize select() masks. */
|
|
FD_ZERO(readset);
|
|
FD_ZERO(writeset);
|
|
|
|
if (compat20) {
|
|
/* wrong: bad condition XXX */
|
|
if (channel_not_very_much_buffered_data())
|
|
FD_SET(connection_in, readset);
|
|
} else {
|
|
/*
|
|
* Read packets from the client unless we have too much
|
|
* buffered stdin or channel data.
|
|
*/
|
|
if (buffer_len(&stdin_buffer) < buffer_high &&
|
|
channel_not_very_much_buffered_data())
|
|
FD_SET(connection_in, readset);
|
|
/*
|
|
* If there is not too much data already buffered going to
|
|
* the client, try to get some more data from the program.
|
|
*/
|
|
if (packet_not_very_much_data_to_write()) {
|
|
if (!fdout_eof)
|
|
FD_SET(fdout, readset);
|
|
if (!fderr_eof)
|
|
FD_SET(fderr, readset);
|
|
}
|
|
/*
|
|
* If we have buffered data, try to write some of that data
|
|
* to the program.
|
|
*/
|
|
if (fdin != -1 && buffer_len(&stdin_buffer) > 0)
|
|
FD_SET(fdin, writeset);
|
|
}
|
|
/* Set masks for channel descriptors. */
|
|
channel_prepare_select(readset, writeset);
|
|
|
|
/*
|
|
* If we have buffered packet data going to the client, mark that
|
|
* descriptor.
|
|
*/
|
|
if (packet_have_data_to_write())
|
|
FD_SET(connection_out, writeset);
|
|
|
|
/* Update the maximum descriptor number if appropriate. */
|
|
if (channel_max_fd() > max_fd)
|
|
max_fd = channel_max_fd();
|
|
|
|
/*
|
|
* If child has terminated and there is enough buffer space to read
|
|
* from it, then read as much as is available and exit.
|
|
*/
|
|
if (child_terminated && packet_not_very_much_data_to_write())
|
|
if (max_time_milliseconds == 0)
|
|
max_time_milliseconds = 100;
|
|
|
|
if (max_time_milliseconds == 0)
|
|
tvp = NULL;
|
|
else {
|
|
tv.tv_sec = max_time_milliseconds / 1000;
|
|
tv.tv_usec = 1000 * (max_time_milliseconds % 1000);
|
|
tvp = &tv;
|
|
}
|
|
if (tvp!=NULL)
|
|
debug2("tvp!=NULL kid %d mili %d", child_terminated, max_time_milliseconds);
|
|
|
|
/* Wait for something to happen, or the timeout to expire. */
|
|
ret = select(max_fd + 1, readset, writeset, NULL, tvp);
|
|
|
|
if (ret < 0) {
|
|
if (errno != EINTR)
|
|
error("select: %.100s", strerror(errno));
|
|
else
|
|
goto retry_select;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Processes input from the client and the program. Input data is stored
|
|
* in buffers and processed later.
|
|
*/
|
|
static void
|
|
process_input(fd_set * readset)
|
|
{
|
|
int len;
|
|
char buf[16384];
|
|
|
|
/* Read and buffer any input data from the client. */
|
|
if (FD_ISSET(connection_in, readset)) {
|
|
len = read(connection_in, buf, sizeof(buf));
|
|
if (len == 0) {
|
|
verbose("Connection closed by remote host.");
|
|
fatal_cleanup();
|
|
} else if (len < 0) {
|
|
if (errno != EINTR && errno != EAGAIN) {
|
|
verbose("Read error from remote host: %.100s", strerror(errno));
|
|
fatal_cleanup();
|
|
}
|
|
} else {
|
|
/* Buffer any received data. */
|
|
packet_process_incoming(buf, len);
|
|
}
|
|
}
|
|
if (compat20)
|
|
return;
|
|
|
|
/* Read and buffer any available stdout data from the program. */
|
|
if (!fdout_eof && FD_ISSET(fdout, readset)) {
|
|
len = read(fdout, buf, sizeof(buf));
|
|
if (len < 0 && (errno == EINTR || errno == EAGAIN)) {
|
|
/* do nothing */
|
|
} else if (len <= 0) {
|
|
fdout_eof = 1;
|
|
} else {
|
|
buffer_append(&stdout_buffer, buf, len);
|
|
fdout_bytes += len;
|
|
}
|
|
}
|
|
/* Read and buffer any available stderr data from the program. */
|
|
if (!fderr_eof && FD_ISSET(fderr, readset)) {
|
|
len = read(fderr, buf, sizeof(buf));
|
|
if (len < 0 && (errno == EINTR || errno == EAGAIN)) {
|
|
/* do nothing */
|
|
} else if (len <= 0) {
|
|
fderr_eof = 1;
|
|
} else {
|
|
buffer_append(&stderr_buffer, buf, len);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Sends data from internal buffers to client program stdin.
|
|
*/
|
|
static void
|
|
process_output(fd_set * writeset)
|
|
{
|
|
int len;
|
|
|
|
/* Write buffered data to program stdin. */
|
|
if (!compat20 && fdin != -1 && FD_ISSET(fdin, writeset)) {
|
|
len = write(fdin, buffer_ptr(&stdin_buffer),
|
|
buffer_len(&stdin_buffer));
|
|
if (len < 0 && (errno == EINTR || errno == EAGAIN)) {
|
|
/* do nothing */
|
|
} else if (len <= 0) {
|
|
#ifdef USE_PIPES
|
|
close(fdin);
|
|
#else
|
|
if (fdin != fdout)
|
|
close(fdin);
|
|
else
|
|
shutdown(fdin, SHUT_WR); /* We will no longer send. */
|
|
#endif
|
|
fdin = -1;
|
|
} else {
|
|
/* Successful write. Consume the data from the buffer. */
|
|
buffer_consume(&stdin_buffer, len);
|
|
/* Update the count of bytes written to the program. */
|
|
stdin_bytes += len;
|
|
}
|
|
}
|
|
/* Send any buffered packet data to the client. */
|
|
if (FD_ISSET(connection_out, writeset))
|
|
packet_write_poll();
|
|
}
|
|
|
|
/*
|
|
* Wait until all buffered output has been sent to the client.
|
|
* This is used when the program terminates.
|
|
*/
|
|
static void
|
|
drain_output(void)
|
|
{
|
|
/* Send any buffered stdout data to the client. */
|
|
if (buffer_len(&stdout_buffer) > 0) {
|
|
packet_start(SSH_SMSG_STDOUT_DATA);
|
|
packet_put_string(buffer_ptr(&stdout_buffer),
|
|
buffer_len(&stdout_buffer));
|
|
packet_send();
|
|
/* Update the count of sent bytes. */
|
|
stdout_bytes += buffer_len(&stdout_buffer);
|
|
}
|
|
/* Send any buffered stderr data to the client. */
|
|
if (buffer_len(&stderr_buffer) > 0) {
|
|
packet_start(SSH_SMSG_STDERR_DATA);
|
|
packet_put_string(buffer_ptr(&stderr_buffer),
|
|
buffer_len(&stderr_buffer));
|
|
packet_send();
|
|
/* Update the count of sent bytes. */
|
|
stderr_bytes += buffer_len(&stderr_buffer);
|
|
}
|
|
/* Wait until all buffered data has been written to the client. */
|
|
packet_write_wait();
|
|
}
|
|
|
|
static void
|
|
process_buffered_input_packets(void)
|
|
{
|
|
dispatch_run(DISPATCH_NONBLOCK, NULL, NULL);
|
|
}
|
|
|
|
/*
|
|
* Performs the interactive session. This handles data transmission between
|
|
* the client and the program. Note that the notion of stdin, stdout, and
|
|
* stderr in this function is sort of reversed: this function writes to
|
|
* stdin (of the child program), and reads from stdout and stderr (of the
|
|
* child program).
|
|
*/
|
|
void
|
|
server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg)
|
|
{
|
|
fd_set readset, writeset;
|
|
int wait_status; /* Status returned by wait(). */
|
|
pid_t wait_pid; /* pid returned by wait(). */
|
|
int waiting_termination = 0; /* Have displayed waiting close message. */
|
|
u_int max_time_milliseconds;
|
|
u_int previous_stdout_buffer_bytes;
|
|
u_int stdout_buffer_bytes;
|
|
int type;
|
|
|
|
debug("Entering interactive session.");
|
|
|
|
/* Initialize the SIGCHLD kludge. */
|
|
child_pid = pid;
|
|
child_terminated = 0;
|
|
signal(SIGCHLD, sigchld_handler);
|
|
|
|
/* Initialize our global variables. */
|
|
fdin = fdin_arg;
|
|
fdout = fdout_arg;
|
|
fderr = fderr_arg;
|
|
|
|
/* nonblocking IO */
|
|
set_nonblock(fdin);
|
|
set_nonblock(fdout);
|
|
/* we don't have stderr for interactive terminal sessions, see below */
|
|
if (fderr != -1)
|
|
set_nonblock(fderr);
|
|
|
|
connection_in = packet_get_connection_in();
|
|
connection_out = packet_get_connection_out();
|
|
|
|
previous_stdout_buffer_bytes = 0;
|
|
|
|
/* Set approximate I/O buffer size. */
|
|
if (packet_is_interactive())
|
|
buffer_high = 4096;
|
|
else
|
|
buffer_high = 64 * 1024;
|
|
|
|
/* Initialize max_fd to the maximum of the known file descriptors. */
|
|
max_fd = fdin;
|
|
if (fdout > max_fd)
|
|
max_fd = fdout;
|
|
if (fderr != -1 && fderr > max_fd)
|
|
max_fd = fderr;
|
|
if (connection_in > max_fd)
|
|
max_fd = connection_in;
|
|
if (connection_out > max_fd)
|
|
max_fd = connection_out;
|
|
|
|
/* Initialize Initialize buffers. */
|
|
buffer_init(&stdin_buffer);
|
|
buffer_init(&stdout_buffer);
|
|
buffer_init(&stderr_buffer);
|
|
|
|
/*
|
|
* If we have no separate fderr (which is the case when we have a pty
|
|
* - there we cannot make difference between data sent to stdout and
|
|
* stderr), indicate that we have seen an EOF from stderr. This way
|
|
* we don\'t need to check the descriptor everywhere.
|
|
*/
|
|
if (fderr == -1)
|
|
fderr_eof = 1;
|
|
|
|
server_init_dispatch();
|
|
|
|
/* Main loop of the server for the interactive session mode. */
|
|
for (;;) {
|
|
|
|
/* Process buffered packets from the client. */
|
|
process_buffered_input_packets();
|
|
|
|
/*
|
|
* If we have received eof, and there is no more pending
|
|
* input data, cause a real eof by closing fdin.
|
|
*/
|
|
if (stdin_eof && fdin != -1 && buffer_len(&stdin_buffer) == 0) {
|
|
#ifdef USE_PIPES
|
|
close(fdin);
|
|
#else
|
|
if (fdin != fdout)
|
|
close(fdin);
|
|
else
|
|
shutdown(fdin, SHUT_WR); /* We will no longer send. */
|
|
#endif
|
|
fdin = -1;
|
|
}
|
|
/* Make packets from buffered stderr data to send to the client. */
|
|
make_packets_from_stderr_data();
|
|
|
|
/*
|
|
* Make packets from buffered stdout data to send to the
|
|
* client. If there is very little to send, this arranges to
|
|
* not send them now, but to wait a short while to see if we
|
|
* are getting more data. This is necessary, as some systems
|
|
* wake up readers from a pty after each separate character.
|
|
*/
|
|
max_time_milliseconds = 0;
|
|
stdout_buffer_bytes = buffer_len(&stdout_buffer);
|
|
if (stdout_buffer_bytes != 0 && stdout_buffer_bytes < 256 &&
|
|
stdout_buffer_bytes != previous_stdout_buffer_bytes) {
|
|
/* try again after a while */
|
|
max_time_milliseconds = 10;
|
|
} else {
|
|
/* Send it now. */
|
|
make_packets_from_stdout_data();
|
|
}
|
|
previous_stdout_buffer_bytes = buffer_len(&stdout_buffer);
|
|
|
|
/* Send channel data to the client. */
|
|
if (packet_not_very_much_data_to_write())
|
|
channel_output_poll();
|
|
|
|
/*
|
|
* Bail out of the loop if the program has closed its output
|
|
* descriptors, and we have no more data to send to the
|
|
* client, and there is no pending buffered data.
|
|
*/
|
|
if (fdout_eof && fderr_eof && !packet_have_data_to_write() &&
|
|
buffer_len(&stdout_buffer) == 0 && buffer_len(&stderr_buffer) == 0) {
|
|
if (!channel_still_open())
|
|
break;
|
|
if (!waiting_termination) {
|
|
const char *s = "Waiting for forwarded connections to terminate...\r\n";
|
|
char *cp;
|
|
waiting_termination = 1;
|
|
buffer_append(&stderr_buffer, s, strlen(s));
|
|
|
|
/* Display list of open channels. */
|
|
cp = channel_open_message();
|
|
buffer_append(&stderr_buffer, cp, strlen(cp));
|
|
xfree(cp);
|
|
}
|
|
}
|
|
/* Sleep in select() until we can do something. */
|
|
wait_until_can_do_something(&readset, &writeset,
|
|
max_time_milliseconds);
|
|
|
|
/* Process any channel events. */
|
|
channel_after_select(&readset, &writeset);
|
|
|
|
/* Process input from the client and from program stdout/stderr. */
|
|
process_input(&readset);
|
|
|
|
/* Process output to the client and to program stdin. */
|
|
process_output(&writeset);
|
|
}
|
|
|
|
/* Cleanup and termination code. */
|
|
|
|
/* Wait until all output has been sent to the client. */
|
|
drain_output();
|
|
|
|
debug("End of interactive session; stdin %ld, stdout (read %ld, sent %ld), stderr %ld bytes.",
|
|
stdin_bytes, fdout_bytes, stdout_bytes, stderr_bytes);
|
|
|
|
/* Free and clear the buffers. */
|
|
buffer_free(&stdin_buffer);
|
|
buffer_free(&stdout_buffer);
|
|
buffer_free(&stderr_buffer);
|
|
|
|
/* Close the file descriptors. */
|
|
if (fdout != -1)
|
|
close(fdout);
|
|
fdout = -1;
|
|
fdout_eof = 1;
|
|
if (fderr != -1)
|
|
close(fderr);
|
|
fderr = -1;
|
|
fderr_eof = 1;
|
|
if (fdin != -1)
|
|
close(fdin);
|
|
fdin = -1;
|
|
|
|
/* Stop listening for channels; this removes unix domain sockets. */
|
|
channel_stop_listening();
|
|
|
|
/* Wait for the child to exit. Get its exit status. */
|
|
wait_pid = wait(&wait_status);
|
|
if (wait_pid == -1) {
|
|
/*
|
|
* It is possible that the wait was handled by SIGCHLD
|
|
* handler. This may result in either: this call
|
|
* returning with EINTR, or: this call returning ECHILD.
|
|
*/
|
|
if (child_terminated)
|
|
wait_status = child_wait_status;
|
|
else
|
|
packet_disconnect("wait: %.100s", strerror(errno));
|
|
} else {
|
|
/* Check if it matches the process we forked. */
|
|
if (wait_pid != pid)
|
|
error("Strange, wait returned pid %d, expected %d",
|
|
wait_pid, pid);
|
|
}
|
|
|
|
/* We no longer want our SIGCHLD handler to be called. */
|
|
signal(SIGCHLD, SIG_DFL);
|
|
|
|
/* Check if it exited normally. */
|
|
if (WIFEXITED(wait_status)) {
|
|
/* Yes, normal exit. Get exit status and send it to the client. */
|
|
debug("Command exited with status %d.", WEXITSTATUS(wait_status));
|
|
packet_start(SSH_SMSG_EXITSTATUS);
|
|
packet_put_int(WEXITSTATUS(wait_status));
|
|
packet_send();
|
|
packet_write_wait();
|
|
|
|
/*
|
|
* Wait for exit confirmation. Note that there might be
|
|
* other packets coming before it; however, the program has
|
|
* already died so we just ignore them. The client is
|
|
* supposed to respond with the confirmation when it receives
|
|
* the exit status.
|
|
*/
|
|
do {
|
|
int plen;
|
|
type = packet_read(&plen);
|
|
}
|
|
while (type != SSH_CMSG_EXIT_CONFIRMATION);
|
|
|
|
debug("Received exit confirmation.");
|
|
return;
|
|
}
|
|
/* Check if the program terminated due to a signal. */
|
|
if (WIFSIGNALED(wait_status))
|
|
packet_disconnect("Command terminated on signal %d.",
|
|
WTERMSIG(wait_status));
|
|
|
|
/* Some weird exit cause. Just exit. */
|
|
packet_disconnect("wait returned status %04x.", wait_status);
|
|
/* NOTREACHED */
|
|
}
|
|
|
|
void
|
|
server_loop2(void)
|
|
{
|
|
fd_set readset, writeset;
|
|
int had_channel = 0;
|
|
int status;
|
|
pid_t pid;
|
|
|
|
debug("Entering interactive session for SSH2.");
|
|
|
|
signal(SIGCHLD, sigchld_handler2);
|
|
child_terminated = 0;
|
|
connection_in = packet_get_connection_in();
|
|
connection_out = packet_get_connection_out();
|
|
max_fd = connection_in;
|
|
if (connection_out > max_fd)
|
|
max_fd = connection_out;
|
|
server_init_dispatch();
|
|
|
|
for (;;) {
|
|
process_buffered_input_packets();
|
|
if (!had_channel && channel_still_open())
|
|
had_channel = 1;
|
|
if (had_channel && !channel_still_open()) {
|
|
debug("!channel_still_open.");
|
|
break;
|
|
}
|
|
if (packet_not_very_much_data_to_write())
|
|
channel_output_poll();
|
|
wait_until_can_do_something(&readset, &writeset, 0);
|
|
if (child_terminated) {
|
|
while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
|
|
session_close_by_pid(pid, status);
|
|
child_terminated = 0;
|
|
}
|
|
channel_after_select(&readset, &writeset);
|
|
process_input(&readset);
|
|
process_output(&writeset);
|
|
}
|
|
signal(SIGCHLD, SIG_DFL);
|
|
while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
|
|
session_close_by_pid(pid, status);
|
|
channel_stop_listening();
|
|
}
|
|
|
|
static void
|
|
server_input_stdin_data(int type, int plen, void *ctxt)
|
|
{
|
|
char *data;
|
|
u_int data_len;
|
|
|
|
/* Stdin data from the client. Append it to the buffer. */
|
|
/* Ignore any data if the client has closed stdin. */
|
|
if (fdin == -1)
|
|
return;
|
|
data = packet_get_string(&data_len);
|
|
packet_integrity_check(plen, (4 + data_len), type);
|
|
buffer_append(&stdin_buffer, data, data_len);
|
|
memset(data, 0, data_len);
|
|
xfree(data);
|
|
}
|
|
|
|
static void
|
|
server_input_eof(int type, int plen, void *ctxt)
|
|
{
|
|
/*
|
|
* Eof from the client. The stdin descriptor to the
|
|
* program will be closed when all buffered data has
|
|
* drained.
|
|
*/
|
|
debug("EOF received for stdin.");
|
|
packet_integrity_check(plen, 0, type);
|
|
stdin_eof = 1;
|
|
}
|
|
|
|
static void
|
|
server_input_window_size(int type, int plen, void *ctxt)
|
|
{
|
|
int row = packet_get_int();
|
|
int col = packet_get_int();
|
|
int xpixel = packet_get_int();
|
|
int ypixel = packet_get_int();
|
|
|
|
debug("Window change received.");
|
|
packet_integrity_check(plen, 4 * 4, type);
|
|
if (fdin != -1)
|
|
pty_change_window_size(fdin, row, col, xpixel, ypixel);
|
|
}
|
|
|
|
static Channel *
|
|
server_request_direct_tcpip(char *ctype)
|
|
{
|
|
int sock, newch;
|
|
char *target, *originator;
|
|
int target_port, originator_port;
|
|
|
|
target = packet_get_string(NULL);
|
|
target_port = packet_get_int();
|
|
originator = packet_get_string(NULL);
|
|
originator_port = packet_get_int();
|
|
packet_done();
|
|
|
|
debug("server_request_direct_tcpip: originator %s port %d, target %s port %d",
|
|
originator, originator_port, target, target_port);
|
|
|
|
/* XXX check permission */
|
|
if (no_port_forwarding_flag || !options.allow_tcp_forwarding) {
|
|
xfree(target);
|
|
xfree(originator);
|
|
return NULL;
|
|
}
|
|
sock = channel_connect_to(target, target_port);
|
|
xfree(target);
|
|
xfree(originator);
|
|
if (sock < 0)
|
|
return NULL;
|
|
newch = channel_new(ctype, SSH_CHANNEL_CONNECTING,
|
|
sock, sock, -1, CHAN_TCP_WINDOW_DEFAULT,
|
|
CHAN_TCP_PACKET_DEFAULT, 0, xstrdup("direct-tcpip"), 1);
|
|
return (newch >= 0) ? channel_lookup(newch) : NULL;
|
|
}
|
|
|
|
static Channel *
|
|
server_request_session(char *ctype)
|
|
{
|
|
int newch;
|
|
|
|
debug("input_session_request");
|
|
packet_done();
|
|
/*
|
|
* A server session has no fd to read or write until a
|
|
* CHANNEL_REQUEST for a shell is made, so we set the type to
|
|
* SSH_CHANNEL_LARVAL. Additionally, a callback for handling all
|
|
* CHANNEL_REQUEST messages is registered.
|
|
*/
|
|
newch = channel_new(ctype, SSH_CHANNEL_LARVAL,
|
|
-1, -1, -1, 0, CHAN_SES_PACKET_DEFAULT,
|
|
0, xstrdup("server-session"), 1);
|
|
if (session_open(newch) == 1) {
|
|
channel_register_callback(newch, SSH2_MSG_CHANNEL_REQUEST,
|
|
session_input_channel_req, (void *)0);
|
|
channel_register_cleanup(newch, session_close_by_channel);
|
|
return channel_lookup(newch);
|
|
} else {
|
|
debug("session open failed, free channel %d", newch);
|
|
channel_free(newch);
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
static void
|
|
server_input_channel_open(int type, int plen, void *ctxt)
|
|
{
|
|
Channel *c = NULL;
|
|
char *ctype;
|
|
u_int len;
|
|
int rchan;
|
|
int rmaxpack;
|
|
int rwindow;
|
|
|
|
ctype = packet_get_string(&len);
|
|
rchan = packet_get_int();
|
|
rwindow = packet_get_int();
|
|
rmaxpack = packet_get_int();
|
|
|
|
debug("server_input_channel_open: ctype %s rchan %d win %d max %d",
|
|
ctype, rchan, rwindow, rmaxpack);
|
|
|
|
if (strcmp(ctype, "session") == 0) {
|
|
c = server_request_session(ctype);
|
|
} else if (strcmp(ctype, "direct-tcpip") == 0) {
|
|
c = server_request_direct_tcpip(ctype);
|
|
}
|
|
if (c != NULL) {
|
|
debug("server_input_channel_open: confirm %s", ctype);
|
|
c->remote_id = rchan;
|
|
c->remote_window = rwindow;
|
|
c->remote_maxpacket = rmaxpack;
|
|
|
|
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("server_input_channel_open: failure %s", ctype);
|
|
packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
|
|
packet_put_int(rchan);
|
|
packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
|
|
packet_put_cstring("bla bla");
|
|
packet_put_cstring("");
|
|
packet_send();
|
|
}
|
|
xfree(ctype);
|
|
}
|
|
|
|
static void
|
|
server_input_global_request(int type, int plen, void *ctxt)
|
|
{
|
|
char *rtype;
|
|
int want_reply;
|
|
int success = 0;
|
|
|
|
rtype = packet_get_string(NULL);
|
|
want_reply = packet_get_char();
|
|
debug("server_input_global_request: rtype %s want_reply %d", rtype, want_reply);
|
|
|
|
if (strcmp(rtype, "tcpip-forward") == 0) {
|
|
struct passwd *pw;
|
|
char *listen_address;
|
|
u_short listen_port;
|
|
|
|
pw = auth_get_user();
|
|
if (pw == NULL)
|
|
fatal("server_input_global_request: no user");
|
|
listen_address = packet_get_string(NULL); /* XXX currently ignored */
|
|
listen_port = (u_short)packet_get_int();
|
|
debug("server_input_global_request: tcpip-forward listen %s port %d",
|
|
listen_address, listen_port);
|
|
|
|
/* check permissions */
|
|
if (!options.allow_tcp_forwarding ||
|
|
no_port_forwarding_flag ||
|
|
(listen_port < IPPORT_RESERVED && pw->pw_uid != 0)) {
|
|
success = 0;
|
|
packet_send_debug("Server has disabled port forwarding.");
|
|
} else {
|
|
/* Start listening on the port */
|
|
channel_request_forwarding(
|
|
listen_address, listen_port,
|
|
/*unspec host_to_connect*/ "<unspec host>",
|
|
/*unspec port_to_connect*/ 0,
|
|
options.gateway_ports, /*remote*/ 1);
|
|
success = 1;
|
|
}
|
|
xfree(listen_address);
|
|
}
|
|
if (want_reply) {
|
|
packet_start(success ?
|
|
SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE);
|
|
packet_send();
|
|
packet_write_wait();
|
|
}
|
|
xfree(rtype);
|
|
}
|
|
|
|
static void
|
|
server_init_dispatch_20(void)
|
|
{
|
|
debug("server_init_dispatch_20");
|
|
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, &server_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, &channel_input_channel_request);
|
|
dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
|
|
dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &server_input_global_request);
|
|
}
|
|
static void
|
|
server_init_dispatch_13(void)
|
|
{
|
|
debug("server_init_dispatch_13");
|
|
dispatch_init(NULL);
|
|
dispatch_set(SSH_CMSG_EOF, &server_input_eof);
|
|
dispatch_set(SSH_CMSG_STDIN_DATA, &server_input_stdin_data);
|
|
dispatch_set(SSH_CMSG_WINDOW_SIZE, &server_input_window_size);
|
|
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);
|
|
}
|
|
static void
|
|
server_init_dispatch_15(void)
|
|
{
|
|
server_init_dispatch_13();
|
|
debug("server_init_dispatch_15");
|
|
dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
|
|
dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_oclose);
|
|
}
|
|
void
|
|
server_init_dispatch()
|
|
{
|
|
if (compat20)
|
|
server_init_dispatch_20();
|
|
else if (compat13)
|
|
server_init_dispatch_13();
|
|
else
|
|
server_init_dispatch_15();
|
|
}
|