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ce0f634270
[auth-krb4.c monitor.h serverloop.c session.c ssh-agent.c sshd.c] pid_t cleanup. Markus need this now to keep hacking. markus@, millert@ ok
1077 lines
30 KiB
C
1077 lines
30 KiB
C
/*
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* Author: Tatu Ylonen <ylo@cs.hut.fi>
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* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
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* All rights reserved
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* Server main loop for handling the interactive session.
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*
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* As far as I am concerned, the code I have written for this software
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* can be used freely for any purpose. Any derived versions of this
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* software must be clearly marked as such, and if the derived work is
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* incompatible with the protocol description in the RFC file, it must be
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* called by a name other than "ssh" or "Secure Shell".
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*
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* SSH2 support by Markus Friedl.
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* Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "includes.h"
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RCSID("$OpenBSD: serverloop.c,v 1.102 2002/06/11 05:46:20 mpech Exp $");
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#include "xmalloc.h"
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#include "packet.h"
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#include "buffer.h"
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#include "log.h"
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#include "servconf.h"
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#include "sshpty.h"
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#include "channels.h"
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#include "compat.h"
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#include "ssh1.h"
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#include "ssh2.h"
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#include "auth.h"
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#include "session.h"
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#include "dispatch.h"
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#include "auth-options.h"
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#include "serverloop.h"
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#include "misc.h"
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#include "kex.h"
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extern ServerOptions options;
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/* XXX */
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extern Kex *xxx_kex;
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static Authctxt *xxx_authctxt;
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static Buffer stdin_buffer; /* Buffer for stdin data. */
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static Buffer stdout_buffer; /* Buffer for stdout data. */
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static Buffer stderr_buffer; /* Buffer for stderr data. */
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static int fdin; /* Descriptor for stdin (for writing) */
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static int fdout; /* Descriptor for stdout (for reading);
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May be same number as fdin. */
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static int fderr; /* Descriptor for stderr. May be -1. */
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static long stdin_bytes = 0; /* Number of bytes written to stdin. */
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static long stdout_bytes = 0; /* Number of stdout bytes sent to client. */
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static long stderr_bytes = 0; /* Number of stderr bytes sent to client. */
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static long fdout_bytes = 0; /* Number of stdout bytes read from program. */
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static int stdin_eof = 0; /* EOF message received from client. */
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static int fdout_eof = 0; /* EOF encountered reading from fdout. */
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static int fderr_eof = 0; /* EOF encountered readung from fderr. */
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static int fdin_is_tty = 0; /* fdin points to a tty. */
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static int connection_in; /* Connection to client (input). */
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static int connection_out; /* Connection to client (output). */
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static int connection_closed = 0; /* Connection to client closed. */
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static u_int buffer_high; /* "Soft" max buffer size. */
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static int client_alive_timeouts = 0;
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/*
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* This SIGCHLD kludge is used to detect when the child exits. The server
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* will exit after that, as soon as forwarded connections have terminated.
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*/
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static volatile sig_atomic_t child_terminated = 0; /* The child has terminated. */
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/* prototypes */
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static void server_init_dispatch(void);
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/*
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* we write to this pipe if a SIGCHLD is caught in order to avoid
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* the race between select() and child_terminated
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*/
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static int notify_pipe[2];
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static void
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notify_setup(void)
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{
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if (pipe(notify_pipe) < 0) {
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error("pipe(notify_pipe) failed %s", strerror(errno));
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} else if ((fcntl(notify_pipe[0], F_SETFD, 1) == -1) ||
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(fcntl(notify_pipe[1], F_SETFD, 1) == -1)) {
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error("fcntl(notify_pipe, F_SETFD) failed %s", strerror(errno));
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close(notify_pipe[0]);
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close(notify_pipe[1]);
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} else {
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set_nonblock(notify_pipe[0]);
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set_nonblock(notify_pipe[1]);
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return;
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}
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notify_pipe[0] = -1; /* read end */
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notify_pipe[1] = -1; /* write end */
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}
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static void
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notify_parent(void)
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{
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if (notify_pipe[1] != -1)
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write(notify_pipe[1], "", 1);
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}
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static void
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notify_prepare(fd_set *readset)
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{
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if (notify_pipe[0] != -1)
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FD_SET(notify_pipe[0], readset);
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}
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static void
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notify_done(fd_set *readset)
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{
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char c;
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if (notify_pipe[0] != -1 && FD_ISSET(notify_pipe[0], readset))
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while (read(notify_pipe[0], &c, 1) != -1)
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debug2("notify_done: reading");
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}
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static void
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sigchld_handler(int sig)
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{
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int save_errno = errno;
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debug("Received SIGCHLD.");
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child_terminated = 1;
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mysignal(SIGCHLD, sigchld_handler);
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notify_parent();
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errno = save_errno;
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}
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/*
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* Make packets from buffered stderr data, and buffer it for sending
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* to the client.
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*/
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static void
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make_packets_from_stderr_data(void)
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{
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int len;
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/* Send buffered stderr data to the client. */
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while (buffer_len(&stderr_buffer) > 0 &&
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packet_not_very_much_data_to_write()) {
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len = buffer_len(&stderr_buffer);
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if (packet_is_interactive()) {
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if (len > 512)
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len = 512;
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} else {
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/* Keep the packets at reasonable size. */
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if (len > packet_get_maxsize())
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len = packet_get_maxsize();
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}
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packet_start(SSH_SMSG_STDERR_DATA);
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packet_put_string(buffer_ptr(&stderr_buffer), len);
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packet_send();
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buffer_consume(&stderr_buffer, len);
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stderr_bytes += len;
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}
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}
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/*
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* Make packets from buffered stdout data, and buffer it for sending to the
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* client.
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*/
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static void
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make_packets_from_stdout_data(void)
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{
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int len;
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/* Send buffered stdout data to the client. */
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while (buffer_len(&stdout_buffer) > 0 &&
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packet_not_very_much_data_to_write()) {
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len = buffer_len(&stdout_buffer);
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if (packet_is_interactive()) {
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if (len > 512)
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len = 512;
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} else {
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/* Keep the packets at reasonable size. */
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if (len > packet_get_maxsize())
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len = packet_get_maxsize();
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}
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packet_start(SSH_SMSG_STDOUT_DATA);
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packet_put_string(buffer_ptr(&stdout_buffer), len);
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packet_send();
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buffer_consume(&stdout_buffer, len);
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stdout_bytes += len;
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}
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}
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static void
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client_alive_check(void)
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{
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static int had_channel = 0;
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int id;
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id = channel_find_open();
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if (id == -1) {
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if (!had_channel)
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return;
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packet_disconnect("No open channels after timeout!");
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}
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had_channel = 1;
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/* timeout, check to see how many we have had */
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if (++client_alive_timeouts > options.client_alive_count_max)
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packet_disconnect("Timeout, your session not responding.");
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/*
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* send a bogus channel request with "wantreply",
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* we should get back a failure
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*/
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channel_request_start(id, "keepalive@openssh.com", 1);
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packet_send();
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}
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/*
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* Sleep in select() until we can do something. This will initialize the
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* select masks. Upon return, the masks will indicate which descriptors
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* have data or can accept data. Optionally, a maximum time can be specified
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* for the duration of the wait (0 = infinite).
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*/
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static void
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wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
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int *nallocp, u_int max_time_milliseconds)
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{
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struct timeval tv, *tvp;
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int ret;
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int client_alive_scheduled = 0;
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/*
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* if using client_alive, set the max timeout accordingly,
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* and indicate that this particular timeout was for client
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* alive by setting the client_alive_scheduled flag.
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*
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* this could be randomized somewhat to make traffic
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* analysis more difficult, but we're not doing it yet.
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*/
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if (compat20 &&
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max_time_milliseconds == 0 && options.client_alive_interval) {
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client_alive_scheduled = 1;
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max_time_milliseconds = options.client_alive_interval * 1000;
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}
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/* Allocate and update select() masks for channel descriptors. */
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channel_prepare_select(readsetp, writesetp, maxfdp, nallocp, 0);
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if (compat20) {
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#if 0
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/* wrong: bad condition XXX */
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if (channel_not_very_much_buffered_data())
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#endif
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FD_SET(connection_in, *readsetp);
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} else {
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/*
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* Read packets from the client unless we have too much
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* buffered stdin or channel data.
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*/
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if (buffer_len(&stdin_buffer) < buffer_high &&
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channel_not_very_much_buffered_data())
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FD_SET(connection_in, *readsetp);
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/*
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* If there is not too much data already buffered going to
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* the client, try to get some more data from the program.
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*/
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if (packet_not_very_much_data_to_write()) {
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if (!fdout_eof)
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FD_SET(fdout, *readsetp);
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if (!fderr_eof)
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FD_SET(fderr, *readsetp);
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}
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/*
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* If we have buffered data, try to write some of that data
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* to the program.
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*/
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if (fdin != -1 && buffer_len(&stdin_buffer) > 0)
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FD_SET(fdin, *writesetp);
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}
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notify_prepare(*readsetp);
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/*
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* If we have buffered packet data going to the client, mark that
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* descriptor.
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*/
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if (packet_have_data_to_write())
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FD_SET(connection_out, *writesetp);
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/*
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* If child has terminated and there is enough buffer space to read
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* from it, then read as much as is available and exit.
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*/
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if (child_terminated && packet_not_very_much_data_to_write())
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if (max_time_milliseconds == 0 || client_alive_scheduled)
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max_time_milliseconds = 100;
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if (max_time_milliseconds == 0)
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tvp = NULL;
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else {
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tv.tv_sec = max_time_milliseconds / 1000;
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tv.tv_usec = 1000 * (max_time_milliseconds % 1000);
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tvp = &tv;
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}
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/* Wait for something to happen, or the timeout to expire. */
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ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp);
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if (ret == -1) {
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memset(*readsetp, 0, *nallocp);
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memset(*writesetp, 0, *nallocp);
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if (errno != EINTR)
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error("select: %.100s", strerror(errno));
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} else if (ret == 0 && client_alive_scheduled)
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client_alive_check();
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notify_done(*readsetp);
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}
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/*
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* Processes input from the client and the program. Input data is stored
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* in buffers and processed later.
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*/
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static void
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process_input(fd_set * readset)
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{
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int len;
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char buf[16384];
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/* Read and buffer any input data from the client. */
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if (FD_ISSET(connection_in, readset)) {
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len = read(connection_in, buf, sizeof(buf));
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if (len == 0) {
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verbose("Connection closed by remote host.");
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connection_closed = 1;
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if (compat20)
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return;
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fatal_cleanup();
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} else if (len < 0) {
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if (errno != EINTR && errno != EAGAIN) {
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verbose("Read error from remote host: %.100s", strerror(errno));
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fatal_cleanup();
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}
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} else {
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/* Buffer any received data. */
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packet_process_incoming(buf, len);
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}
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}
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if (compat20)
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return;
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/* Read and buffer any available stdout data from the program. */
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if (!fdout_eof && FD_ISSET(fdout, readset)) {
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len = read(fdout, buf, sizeof(buf));
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if (len < 0 && (errno == EINTR || errno == EAGAIN)) {
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/* do nothing */
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} else if (len <= 0) {
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fdout_eof = 1;
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} else {
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buffer_append(&stdout_buffer, buf, len);
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fdout_bytes += len;
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}
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}
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/* Read and buffer any available stderr data from the program. */
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if (!fderr_eof && FD_ISSET(fderr, readset)) {
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len = read(fderr, buf, sizeof(buf));
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if (len < 0 && (errno == EINTR || errno == EAGAIN)) {
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/* do nothing */
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} else if (len <= 0) {
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fderr_eof = 1;
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} else {
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buffer_append(&stderr_buffer, buf, len);
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}
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}
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}
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/*
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* Sends data from internal buffers to client program stdin.
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*/
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static void
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process_output(fd_set * writeset)
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{
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struct termios tio;
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u_char *data;
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u_int dlen;
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int len;
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/* Write buffered data to program stdin. */
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if (!compat20 && fdin != -1 && FD_ISSET(fdin, writeset)) {
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data = buffer_ptr(&stdin_buffer);
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dlen = buffer_len(&stdin_buffer);
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len = write(fdin, data, dlen);
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if (len < 0 && (errno == EINTR || errno == EAGAIN)) {
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/* do nothing */
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} else if (len <= 0) {
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if (fdin != fdout)
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close(fdin);
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else
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shutdown(fdin, SHUT_WR); /* We will no longer send. */
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fdin = -1;
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} else {
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/* Successful write. */
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if (fdin_is_tty && dlen >= 1 && data[0] != '\r' &&
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tcgetattr(fdin, &tio) == 0 &&
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!(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
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/*
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* Simulate echo to reduce the impact of
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* traffic analysis
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*/
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packet_send_ignore(len);
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packet_send();
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}
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/* Consume the data from the buffer. */
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buffer_consume(&stdin_buffer, len);
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/* Update the count of bytes written to the program. */
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stdin_bytes += len;
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}
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}
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/* Send any buffered packet data to the client. */
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if (FD_ISSET(connection_out, writeset))
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packet_write_poll();
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}
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/*
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* Wait until all buffered output has been sent to the client.
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* This is used when the program terminates.
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*/
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static void
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drain_output(void)
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{
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/* Send any buffered stdout data to the client. */
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if (buffer_len(&stdout_buffer) > 0) {
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packet_start(SSH_SMSG_STDOUT_DATA);
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packet_put_string(buffer_ptr(&stdout_buffer),
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buffer_len(&stdout_buffer));
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packet_send();
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/* Update the count of sent bytes. */
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stdout_bytes += buffer_len(&stdout_buffer);
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}
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/* Send any buffered stderr data to the client. */
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if (buffer_len(&stderr_buffer) > 0) {
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packet_start(SSH_SMSG_STDERR_DATA);
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packet_put_string(buffer_ptr(&stderr_buffer),
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buffer_len(&stderr_buffer));
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packet_send();
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/* Update the count of sent bytes. */
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stderr_bytes += buffer_len(&stderr_buffer);
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}
|
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/* Wait until all buffered data has been written to the client. */
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packet_write_wait();
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}
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|
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static void
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process_buffered_input_packets(void)
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{
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dispatch_run(DISPATCH_NONBLOCK, NULL, compat20 ? xxx_kex : NULL);
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}
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|
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/*
|
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* Performs the interactive session. This handles data transmission between
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* the client and the program. Note that the notion of stdin, stdout, and
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* stderr in this function is sort of reversed: this function writes to
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* stdin (of the child program), and reads from stdout and stderr (of the
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* child program).
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*/
|
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void
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server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg)
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{
|
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fd_set *readset = NULL, *writeset = NULL;
|
|
int max_fd = 0, nalloc = 0;
|
|
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;
|
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u_int stdout_buffer_bytes;
|
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int type;
|
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|
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debug("Entering interactive session.");
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|
|
/* Initialize the SIGCHLD kludge. */
|
|
child_terminated = 0;
|
|
mysignal(SIGCHLD, sigchld_handler);
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|
|
/* 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);
|
|
|
|
if (!(datafellows & SSH_BUG_IGNOREMSG) && isatty(fdin))
|
|
fdin_is_tty = 1;
|
|
|
|
connection_in = packet_get_connection_in();
|
|
connection_out = packet_get_connection_out();
|
|
|
|
notify_setup();
|
|
|
|
previous_stdout_buffer_bytes = 0;
|
|
|
|
/* Set approximate I/O buffer size. */
|
|
if (packet_is_interactive())
|
|
buffer_high = 4096;
|
|
else
|
|
buffer_high = 64 * 1024;
|
|
|
|
#if 0
|
|
/* Initialize max_fd to the maximum of the known file descriptors. */
|
|
max_fd = MAX(connection_in, connection_out);
|
|
max_fd = MAX(max_fd, fdin);
|
|
max_fd = MAX(max_fd, fdout);
|
|
if (fderr != -1)
|
|
max_fd = MAX(max_fd, fderr);
|
|
#endif
|
|
|
|
/* 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) {
|
|
if (fdin != fdout)
|
|
close(fdin);
|
|
else
|
|
shutdown(fdin, SHUT_WR); /* We will no longer send. */
|
|
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);
|
|
}
|
|
}
|
|
max_fd = MAX(connection_in, connection_out);
|
|
max_fd = MAX(max_fd, fdin);
|
|
max_fd = MAX(max_fd, fdout);
|
|
max_fd = MAX(max_fd, fderr);
|
|
max_fd = MAX(max_fd, notify_pipe[0]);
|
|
|
|
/* Sleep in select() until we can do something. */
|
|
wait_until_can_do_something(&readset, &writeset, &max_fd,
|
|
&nalloc, 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);
|
|
}
|
|
if (readset)
|
|
xfree(readset);
|
|
if (writeset)
|
|
xfree(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;
|
|
|
|
channel_free_all();
|
|
|
|
/* We no longer want our SIGCHLD handler to be called. */
|
|
mysignal(SIGCHLD, SIG_DFL);
|
|
|
|
while ((wait_pid = waitpid(-1, &wait_status, 0)) < 0)
|
|
if (errno != EINTR)
|
|
packet_disconnect("wait: %.100s", strerror(errno));
|
|
if (wait_pid != pid)
|
|
error("Strange, wait returned pid %ld, expected %ld",
|
|
(long)wait_pid, (long)pid);
|
|
|
|
/* 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 {
|
|
type = packet_read();
|
|
}
|
|
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 */
|
|
}
|
|
|
|
static void
|
|
collect_children(void)
|
|
{
|
|
pid_t pid;
|
|
sigset_t oset, nset;
|
|
int status;
|
|
|
|
/* block SIGCHLD while we check for dead children */
|
|
sigemptyset(&nset);
|
|
sigaddset(&nset, SIGCHLD);
|
|
sigprocmask(SIG_BLOCK, &nset, &oset);
|
|
if (child_terminated) {
|
|
while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
|
|
(pid < 0 && errno == EINTR))
|
|
if (pid > 0)
|
|
session_close_by_pid(pid, status);
|
|
child_terminated = 0;
|
|
}
|
|
sigprocmask(SIG_SETMASK, &oset, NULL);
|
|
}
|
|
|
|
void
|
|
server_loop2(Authctxt *authctxt)
|
|
{
|
|
fd_set *readset = NULL, *writeset = NULL;
|
|
int rekeying = 0, max_fd, nalloc = 0;
|
|
|
|
debug("Entering interactive session for SSH2.");
|
|
|
|
mysignal(SIGCHLD, sigchld_handler);
|
|
child_terminated = 0;
|
|
connection_in = packet_get_connection_in();
|
|
connection_out = packet_get_connection_out();
|
|
|
|
notify_setup();
|
|
|
|
max_fd = MAX(connection_in, connection_out);
|
|
max_fd = MAX(max_fd, notify_pipe[0]);
|
|
|
|
xxx_authctxt = authctxt;
|
|
|
|
server_init_dispatch();
|
|
|
|
for (;;) {
|
|
process_buffered_input_packets();
|
|
|
|
rekeying = (xxx_kex != NULL && !xxx_kex->done);
|
|
|
|
if (!rekeying && packet_not_very_much_data_to_write())
|
|
channel_output_poll();
|
|
wait_until_can_do_something(&readset, &writeset, &max_fd,
|
|
&nalloc, 0);
|
|
|
|
collect_children();
|
|
if (!rekeying)
|
|
channel_after_select(readset, writeset);
|
|
process_input(readset);
|
|
if (connection_closed)
|
|
break;
|
|
process_output(writeset);
|
|
}
|
|
collect_children();
|
|
|
|
if (readset)
|
|
xfree(readset);
|
|
if (writeset)
|
|
xfree(writeset);
|
|
|
|
/* free all channels, no more reads and writes */
|
|
channel_free_all();
|
|
|
|
/* free remaining sessions, e.g. remove wtmp entries */
|
|
session_destroy_all(NULL);
|
|
}
|
|
|
|
static void
|
|
server_input_channel_failure(int type, u_int32_t seq, void *ctxt)
|
|
{
|
|
debug("Got CHANNEL_FAILURE for keepalive");
|
|
/*
|
|
* reset timeout, since we got a sane answer from the client.
|
|
* even if this was generated by something other than
|
|
* the bogus CHANNEL_REQUEST we send for keepalives.
|
|
*/
|
|
client_alive_timeouts = 0;
|
|
}
|
|
|
|
|
|
static void
|
|
server_input_stdin_data(int type, u_int32_t seq, 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_check_eom();
|
|
buffer_append(&stdin_buffer, data, data_len);
|
|
memset(data, 0, data_len);
|
|
xfree(data);
|
|
}
|
|
|
|
static void
|
|
server_input_eof(int type, u_int32_t seq, 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_check_eom();
|
|
stdin_eof = 1;
|
|
}
|
|
|
|
static void
|
|
server_input_window_size(int type, u_int32_t seq, 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_check_eom();
|
|
if (fdin != -1)
|
|
pty_change_window_size(fdin, row, col, xpixel, ypixel);
|
|
}
|
|
|
|
static Channel *
|
|
server_request_direct_tcpip(char *ctype)
|
|
{
|
|
Channel *c;
|
|
int sock;
|
|
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_check_eom();
|
|
|
|
debug("server_request_direct_tcpip: originator %s port %d, target %s port %d",
|
|
originator, originator_port, target, target_port);
|
|
|
|
/* XXX check permission */
|
|
sock = channel_connect_to(target, target_port);
|
|
xfree(target);
|
|
xfree(originator);
|
|
if (sock < 0)
|
|
return NULL;
|
|
c = channel_new(ctype, SSH_CHANNEL_CONNECTING,
|
|
sock, sock, -1, CHAN_TCP_WINDOW_DEFAULT,
|
|
CHAN_TCP_PACKET_DEFAULT, 0, xstrdup("direct-tcpip"), 1);
|
|
return c;
|
|
}
|
|
|
|
static Channel *
|
|
server_request_session(char *ctype)
|
|
{
|
|
Channel *c;
|
|
|
|
debug("input_session_request");
|
|
packet_check_eom();
|
|
/*
|
|
* 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.
|
|
*/
|
|
c = channel_new(ctype, SSH_CHANNEL_LARVAL,
|
|
-1, -1, -1, /*window size*/0, CHAN_SES_PACKET_DEFAULT,
|
|
0, xstrdup("server-session"), 1);
|
|
if (session_open(xxx_authctxt, c->self) != 1) {
|
|
debug("session open failed, free channel %d", c->self);
|
|
channel_free(c);
|
|
return NULL;
|
|
}
|
|
channel_register_cleanup(c->self, session_close_by_channel);
|
|
return c;
|
|
}
|
|
|
|
static void
|
|
server_input_channel_open(int type, u_int32_t seq, 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;
|
|
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("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);
|
|
if (!(datafellows & SSH_BUG_OPENFAILURE)) {
|
|
packet_put_cstring("open failed");
|
|
packet_put_cstring("");
|
|
}
|
|
packet_send();
|
|
}
|
|
xfree(ctype);
|
|
}
|
|
|
|
static void
|
|
server_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("server_input_global_request: rtype %s want_reply %d", rtype, want_reply);
|
|
|
|
/* -R style forwarding */
|
|
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 */
|
|
success = channel_setup_remote_fwd_listener(
|
|
listen_address, listen_port, options.gateway_ports);
|
|
}
|
|
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_input_channel_req(int type, u_int32_t seq, void *ctxt)
|
|
{
|
|
Channel *c;
|
|
int id, reply, success = 0;
|
|
char *rtype;
|
|
|
|
id = packet_get_int();
|
|
rtype = packet_get_string(NULL);
|
|
reply = packet_get_char();
|
|
|
|
debug("server_input_channel_req: channel %d request %s reply %d",
|
|
id, rtype, reply);
|
|
|
|
if ((c = channel_lookup(id)) == NULL)
|
|
packet_disconnect("server_input_channel_req: "
|
|
"unknown channel %d", id);
|
|
if (c->type == SSH_CHANNEL_LARVAL || c->type == SSH_CHANNEL_OPEN)
|
|
success = session_input_channel_req(c, rtype);
|
|
if (reply) {
|
|
packet_start(success ?
|
|
SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
|
|
packet_put_int(c->remote_id);
|
|
packet_send();
|
|
}
|
|
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, &server_input_channel_req);
|
|
dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
|
|
dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &server_input_global_request);
|
|
/* client_alive */
|
|
dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &server_input_channel_failure);
|
|
/* rekeying */
|
|
dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
|
|
}
|
|
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);
|
|
}
|
|
static void
|
|
server_init_dispatch(void)
|
|
{
|
|
if (compat20)
|
|
server_init_dispatch_20();
|
|
else if (compat13)
|
|
server_init_dispatch_13();
|
|
else
|
|
server_init_dispatch_15();
|
|
}
|