Revert part of 180714 - the intent was to flatten dist, not to nuke it.

1 files changed, 1219 insertions, 0 deletions

diff --git a/crypto/openssh/serverloop.c b/crypto/openssh/serverloop.c
new file mode 100644
index 0000000..69304b5
--- /dev/null
+++ b/crypto/openssh/serverloop.c
@@ -0,0 +1,1219 @@
+/* $OpenBSD: serverloop.c,v 1.145 2006/10/11 12:38:03 markus 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, 2001 Markus Friedl.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "includes.h"
+
+#include <sys/types.h>
+#include <sys/param.h>
+#include <sys/wait.h>
+#include <sys/socket.h>
+#ifdef HAVE_SYS_TIME_H
+# include <sys/time.h>
+#endif
+
+#include <netinet/in.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <pwd.h>
+#include <signal.h>
+#include <string.h>
+#include <termios.h>
+#include <unistd.h>
+#include <stdarg.h>
+
+#include "xmalloc.h"
+#include "packet.h"
+#include "buffer.h"
+#include "log.h"
+#include "servconf.h"
+#include "canohost.h"
+#include "sshpty.h"
+#include "channels.h"
+#include "compat.h"
+#include "ssh1.h"
+#include "ssh2.h"
+#include "key.h"
+#include "cipher.h"
+#include "kex.h"
+#include "hostfile.h"
+#include "auth.h"
+#include "session.h"
+#include "dispatch.h"
+#include "auth-options.h"
+#include "serverloop.h"
+#include "misc.h"
+
+extern ServerOptions options;
+
+/* XXX */
+extern Kex *xxx_kex;
+extern Authctxt *the_authctxt;
+extern int use_privsep;
+
+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 fdin_is_tty = 0;	/* fdin points to a tty. */
+static int connection_in;	/* Connection to client (input). */
+static int connection_out;	/* Connection to client (output). */
+static int connection_closed = 0;	/* Connection to client closed. */
+static u_int buffer_high;	/* "Soft" max buffer size. */
+static int client_alive_timeouts = 0;
+
+/*
+ * 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 volatile sig_atomic_t child_terminated = 0;	/* The child has terminated. */
+
+/* Cleanup on signals (!use_privsep case only) */
+static volatile sig_atomic_t received_sigterm = 0;
+
+/* prototypes */
+static void server_init_dispatch(void);
+
+/*
+ * we write to this pipe if a SIGCHLD is caught in order to avoid
+ * the race between select() and child_terminated
+ */
+static int notify_pipe[2];
+static void
+notify_setup(void)
+{
+	if (pipe(notify_pipe) < 0) {
+		error("pipe(notify_pipe) failed %s", strerror(errno));
+	} else if ((fcntl(notify_pipe[0], F_SETFD, 1) == -1) ||
+	    (fcntl(notify_pipe[1], F_SETFD, 1) == -1)) {
+		error("fcntl(notify_pipe, F_SETFD) failed %s", strerror(errno));
+		close(notify_pipe[0]);
+		close(notify_pipe[1]);
+	} else {
+		set_nonblock(notify_pipe[0]);
+		set_nonblock(notify_pipe[1]);
+		return;
+	}
+	notify_pipe[0] = -1;	/* read end */
+	notify_pipe[1] = -1;	/* write end */
+}
+static void
+notify_parent(void)
+{
+	if (notify_pipe[1] != -1)
+		write(notify_pipe[1], "", 1);
+}
+static void
+notify_prepare(fd_set *readset)
+{
+	if (notify_pipe[0] != -1)
+		FD_SET(notify_pipe[0], readset);
+}
+static void
+notify_done(fd_set *readset)
+{
+	char c;
+
+	if (notify_pipe[0] != -1 && FD_ISSET(notify_pipe[0], readset))
+		while (read(notify_pipe[0], &c, 1) != -1)
+			debug2("notify_done: reading");
+}
+
+/*ARGSUSED*/
+static void
+sigchld_handler(int sig)
+{
+	int save_errno = errno;
+	child_terminated = 1;
+#ifndef _UNICOS
+	mysignal(SIGCHLD, sigchld_handler);
+#endif
+	notify_parent();
+	errno = save_errno;
+}
+
+/*ARGSUSED*/
+static void
+sigterm_handler(int sig)
+{
+	received_sigterm = sig;
+}
+
+/*
+ * Make packets from buffered stderr data, and buffer it for sending
+ * to the client.
+ */
+static void
+make_packets_from_stderr_data(void)
+{
+	u_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)
+{
+	u_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;
+	}
+}
+
+static void
+client_alive_check(void)
+{
+	int channel_id;
+
+	/* timeout, check to see how many we have had */
+	if (++client_alive_timeouts > options.client_alive_count_max) {
+		logit("Timeout, client not responding.");
+		cleanup_exit(255);
+	}
+
+	/*
+	 * send a bogus global/channel request with "wantreply",
+	 * we should get back a failure
+	 */
+	if ((channel_id = channel_find_open()) == -1) {
+		packet_start(SSH2_MSG_GLOBAL_REQUEST);
+		packet_put_cstring("keepalive@openssh.com");
+		packet_put_char(1);	/* boolean: want reply */
+	} else {
+		channel_request_start(channel_id, "keepalive@openssh.com", 1);
+	}
+	packet_send();
+}
+
+/*
+ * 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 **readsetp, fd_set **writesetp, int *maxfdp,
+    u_int *nallocp, u_int max_time_milliseconds)
+{
+	struct timeval tv, *tvp;
+	int ret;
+	int client_alive_scheduled = 0;
+
+	/*
+	 * if using client_alive, set the max timeout accordingly,
+	 * and indicate that this particular timeout was for client
+	 * alive by setting the client_alive_scheduled flag.
+	 *
+	 * this could be randomized somewhat to make traffic
+	 * analysis more difficult, but we're not doing it yet.
+	 */
+	if (compat20 &&
+	    max_time_milliseconds == 0 && options.client_alive_interval) {
+		client_alive_scheduled = 1;
+		max_time_milliseconds = options.client_alive_interval * 1000;
+	}
+
+	/* Allocate and update select() masks for channel descriptors. */
+	channel_prepare_select(readsetp, writesetp, maxfdp, nallocp, 0);
+
+	if (compat20) {
+#if 0
+		/* wrong: bad condition XXX */
+		if (channel_not_very_much_buffered_data())
+#endif
+		FD_SET(connection_in, *readsetp);
+	} 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, *readsetp);
+		/*
+		 * 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, *readsetp);
+			if (!fderr_eof)
+				FD_SET(fderr, *readsetp);
+		}
+		/*
+		 * 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, *writesetp);
+	}
+	notify_prepare(*readsetp);
+
+	/*
+	 * If we have buffered packet data going to the client, mark that
+	 * descriptor.
+	 */
+	if (packet_have_data_to_write())
+		FD_SET(connection_out, *writesetp);
+
+	/*
+	 * 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 || client_alive_scheduled)
+			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;
+	}
+
+	/* Wait for something to happen, or the timeout to expire. */
+	ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp);
+
+	if (ret == -1) {
+		memset(*readsetp, 0, *nallocp);
+		memset(*writesetp, 0, *nallocp);
+		if (errno != EINTR)
+			error("select: %.100s", strerror(errno));
+	} else if (ret == 0 && client_alive_scheduled)
+		client_alive_check();
+
+	notify_done(*readsetp);
+}
+
+/*
+ * 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 %.100s",
+			    get_remote_ipaddr());
+			connection_closed = 1;
+			if (compat20)
+				return;
+			cleanup_exit(255);
+		} else if (len < 0) {
+			if (errno != EINTR && errno != EAGAIN) {
+				verbose("Read error from remote host "
+				    "%.100s: %.100s",
+				    get_remote_ipaddr(), strerror(errno));
+				cleanup_exit(255);
+			}
+		} 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)) {
+		errno = 0;
+		len = read(fdout, buf, sizeof(buf));
+		if (len < 0 && (errno == EINTR || errno == EAGAIN)) {
+			/* do nothing */
+#ifndef PTY_ZEROREAD
+		} else if (len <= 0) {
+#else
+		} else if ((!isatty(fdout) && len <= 0) ||
+		    (isatty(fdout) && (len < 0 || (len == 0 && errno != 0)))) {
+#endif
+			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)) {
+		errno = 0;
+		len = read(fderr, buf, sizeof(buf));
+		if (len < 0 && (errno == EINTR || errno == EAGAIN)) {
+			/* do nothing */
+#ifndef PTY_ZEROREAD
+		} else if (len <= 0) {
+#else
+		} else if ((!isatty(fderr) && len <= 0) ||
+		    (isatty(fderr) && (len < 0 || (len == 0 && errno != 0)))) {
+#endif
+			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)
+{
+	struct termios tio;
+	u_char *data;
+	u_int dlen;
+	int len;
+
+	/* Write buffered data to program stdin. */
+	if (!compat20 && fdin != -1 && FD_ISSET(fdin, writeset)) {
+		data = buffer_ptr(&stdin_buffer);
+		dlen = buffer_len(&stdin_buffer);
+		len = write(fdin, data, dlen);
+		if (len < 0 && (errno == EINTR || errno == EAGAIN)) {
+			/* do nothing */
+		} else if (len <= 0) {
+			if (fdin != fdout)
+				close(fdin);
+			else
+				shutdown(fdin, SHUT_WR); /* We will no longer send. */
+			fdin = -1;
+		} else {
+			/* Successful write. */
+			if (fdin_is_tty && dlen >= 1 && data[0] != '\r' &&
+			    tcgetattr(fdin, &tio) == 0 &&
+			    !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
+				/*
+				 * Simulate echo to reduce the impact of
+				 * traffic analysis
+				 */
+				packet_send_ignore(len);
+				packet_send();
+			}
+			/* 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, compat20 ? xxx_kex : 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 = NULL, *writeset = NULL;
+	int max_fd = 0;
+	u_int 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;
+	u_int stdout_buffer_bytes;
+	int type;
+
+	debug("Entering interactive session.");
+
+	/* Initialize the SIGCHLD kludge. */
+	child_terminated = 0;
+	mysignal(SIGCHLD, sigchld_handler);
+
+	if (!use_privsep) {
+		signal(SIGTERM, sigterm_handler);
+		signal(SIGINT, sigterm_handler);
+		signal(SIGQUIT, sigterm_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);
+
+	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);
+
+		if (received_sigterm) {
+			logit("Exiting on signal %d", received_sigterm);
+			/* Clean up sessions, utmp, etc. */
+			cleanup_exit(255);
+		}
+
+		/* 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) {
+		debug("Received SIGCHLD.");
+		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();
+
+	if (!use_privsep) {
+		signal(SIGTERM, sigterm_handler);
+		signal(SIGINT, sigterm_handler);
+		signal(SIGQUIT, sigterm_handler);
+	}
+
+	notify_setup();
+
+	max_fd = MAX(connection_in, connection_out);
+	max_fd = MAX(max_fd, notify_pipe[0]);
+
+	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);
+
+		if (received_sigterm) {
+			logit("Exiting on signal %d", received_sigterm);
+			/* Clean up sessions, utmp, etc. */
+			cleanup_exit(255);
+		}
+
+		collect_children();
+		if (!rekeying) {
+			channel_after_select(readset, writeset);
+			if (packet_need_rekeying()) {
+				debug("need rekeying");
+				xxx_kex->done = 0;
+				kex_send_kexinit(xxx_kex);
+			}
+		}
+		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_keep_alive(int type, u_int32_t seq, void *ctxt)
+{
+	debug("Got %d/%u for keepalive", type, seq);
+	/*
+	 * 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)
+{
+	u_int row = packet_get_int();
+	u_int col = packet_get_int();
+	u_int xpixel = packet_get_int();
+	u_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(void)
+{
+	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("direct-tcpip", SSH_CHANNEL_CONNECTING,
+	    sock, sock, -1, CHAN_TCP_WINDOW_DEFAULT,
+	    CHAN_TCP_PACKET_DEFAULT, 0, "direct-tcpip", 1);
+	return c;
+}
+
+static Channel *
+server_request_tun(void)
+{
+	Channel *c = NULL;
+	int mode, tun;
+	int sock;
+
+	mode = packet_get_int();
+	switch (mode) {
+	case SSH_TUNMODE_POINTOPOINT:
+	case SSH_TUNMODE_ETHERNET:
+		break;
+	default:
+		packet_send_debug("Unsupported tunnel device mode.");
+		return NULL;
+	}
+	if ((options.permit_tun & mode) == 0) {
+		packet_send_debug("Server has rejected tunnel device "
+		    "forwarding");
+		return NULL;
+	}
+
+	tun = packet_get_int();
+	if (forced_tun_device != -1) {
+		if (tun != SSH_TUNID_ANY && forced_tun_device != tun)
+			goto done;
+		tun = forced_tun_device;
+	}
+	sock = tun_open(tun, mode);
+	if (sock < 0)
+		goto done;
+	c = channel_new("tun", SSH_CHANNEL_OPEN, sock, sock, -1,
+	    CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1);
+	c->datagram = 1;
+#if defined(SSH_TUN_FILTER)
+	if (mode == SSH_TUNMODE_POINTOPOINT)
+		channel_register_filter(c->self, sys_tun_infilter,
+		    sys_tun_outfilter);
+#endif
+
+ done:
+	if (c == NULL)
+		packet_send_debug("Failed to open the tunnel device.");
+	return c;
+}
+
+static Channel *
+server_request_session(void)
+{
+	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("session", SSH_CHANNEL_LARVAL,
+	    -1, -1, -1, /*window size*/0, CHAN_SES_PACKET_DEFAULT,
+	    0, "server-session", 1);
+	if (session_open(the_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, 0);
+	return c;
+}
+
+static void
+server_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("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();
+	} else if (strcmp(ctype, "direct-tcpip") == 0) {
+		c = server_request_direct_tcpip();
+	} else if (strcmp(ctype, "tun@openssh.com") == 0) {
+		c = server_request_tun();
+	}
+	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 = the_authctxt->pw;
+		if (pw == NULL || !the_authctxt->valid)
+			fatal("server_input_global_request: no/invalid user");
+		listen_address = packet_get_string(NULL);
+		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
+#ifndef NO_IPPORT_RESERVED_CONCEPT
+		    || (listen_port < IPPORT_RESERVED && pw->pw_uid != 0)
+#endif
+		    ) {
+			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);
+	} else if (strcmp(rtype, "cancel-tcpip-forward") == 0) {
+		char *cancel_address;
+		u_short cancel_port;
+
+		cancel_address = packet_get_string(NULL);
+		cancel_port = (u_short)packet_get_int();
+		debug("%s: cancel-tcpip-forward addr %s port %d", __func__,
+		    cancel_address, cancel_port);
+
+		success = channel_cancel_rport_listener(cancel_address,
+		    cancel_port);
+		xfree(cancel_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_keep_alive);
+	dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &server_input_keep_alive);
+	dispatch_set(SSH2_MSG_REQUEST_FAILURE, &server_input_keep_alive);
+	/* 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();
+}