/*
  Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
  2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012,
  2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021 Free Software
  Foundation, Inc.

  This file is part of GNU Inetutils.

  GNU Inetutils is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or (at
  your option) any later version.

  GNU Inetutils is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program.  If not, see `http://www.gnu.org/licenses/'. */

/*
 * Copyright (c) 1985, 1993
 *	The Regents of the University of California.  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.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
 */

/* This code is derived from software contributed to Berkeley by Rick
   Adams. */

/*
 * TCP/IP server for uucico.
 * uucico's TCP channel causes this server to be run at the remote end.
 */

#include <config.h>

#include <sys/types.h>
#include <sys/wait.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <fcntl.h>
#include <sys/time.h>
#include <time.h>
#include <pwd.h>
#include <grp.h>
#include <unistd.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifdef HAVE_CRYPT_H
# include <crypt.h>
#endif
#include <termios.h>
#ifdef HAVE_UTMPX_H
# include <utmpx.h>
#endif
#ifdef HAVE_UTMP_H
# include <utmp.h>
#endif

#include <argp.h>
#include <progname.h>
#include <unused-parameter.h>
#include <libinetutils.h>

void dologin (struct passwd *pw, struct sockaddr *sap, socklen_t salen);
void dologout (void);
void doit (struct sockaddr *sap, socklen_t salen);

char *uucico_location = PATH_UUCICO;
int mypid;

char Username[72];
char Logname[72];
char *nenv[] = {
  Username,
  Logname,
  NULL,
};

extern char **environ;

static struct argp_option argp_options[] = {
#define GRP 10
  { "uucico", 'u', "LOCATION", 0,
    "location of uucico executable, "
    "replacing default at " PATH_UUCICO, GRP },
#undef GRP
  { NULL, 0, NULL, 0, NULL, 0 }
};

static error_t
parse_opt (int key, char *arg,
	   struct argp_state *state _GL_UNUSED_PARAMETER)
{
  switch (key)
    {
    case 'u':
      uucico_location = arg;
      break;
    default:
      return ARGP_ERR_UNKNOWN;
    }
  return 0;
}

static struct argp argp =
  {
    argp_options, parse_opt, NULL,
    "TCP/IP server for uucico.",
    NULL, NULL, NULL
  };

int
main (int argc, char **argv)
{
  struct sockaddr_storage hisctladdr;
  socklen_t hisaddrlen = sizeof (hisctladdr);

  set_program_name (argv[0]);
  iu_argp_init ("uucpd", default_program_authors);
  argp_parse (&argp, argc, argv, 0, NULL, NULL);

  /* Minimal environment, containing only USER.  */
  environ = nenv;

  /* Circumvent all descriptor trickery.  */
  dup2 (STDIN_FILENO, STDOUT_FILENO);
  dup2 (STDIN_FILENO, STDERR_FILENO);

  hisaddrlen = sizeof (hisctladdr);
  if (getpeername (STDIN_FILENO, (struct sockaddr *) &hisctladdr,
		   &hisaddrlen) < 0)
    {
      fprintf (stderr, "%s: ", argv[0]);
      perror ("getpeername");
      _exit (EXIT_FAILURE);
    }

  if (fork () == 0)
    doit ((struct sockaddr *) &hisctladdr, hisaddrlen);

  dologout ();
  exit (EXIT_FAILURE);
}

static int
readline (register char *p, register int n)
{
  char c;

  while (n-- > 0)
    {
      if (read (STDIN_FILENO, &c, 1) <= 0)
	return (-1);
      c &= 0177;
      if (c == '\n' || c == '\r')
	{
	  *p = '\0';
	  return (0);
	}
      *p++ = c;
    }
  return (-1);
}

void
doit (struct sockaddr *sap, socklen_t salen)
{
  struct passwd *pw;
  char user[64], passwd[64];
  char *xpasswd;

  alarm (60);
  printf ("login: ");
  fflush (stdout);
  if (readline (user, sizeof (user)) < 0)
    {
      fprintf (stderr, "user read\n");
      return;
    }
  user[sizeof (user) - 1] = '\0';

  pw = getpwnam (user);
  if (pw == NULL)
    {
      /* Simulate continuation, in order not
       * to disclose user name information.
       */
      printf ("Password: ");
      fflush (stdout);
      if (readline (passwd, sizeof (passwd)) < 0)
	{
	  fprintf (stderr, "passwd read\n");
	  return;
	}
      fprintf (stderr, "Login incorrect.");
      return;
    }
  if (pw->pw_passwd && *pw->pw_passwd != '\0')
    {
      printf ("Password: ");
      fflush (stdout);
      if (readline (passwd, sizeof (passwd)) < 0)
	{
	  fprintf (stderr, "passwd read\n");
	  return;
	}
      xpasswd = crypt (passwd, pw->pw_passwd);
      if (strcmp (xpasswd, pw->pw_passwd))
	{
	  fprintf (stderr, "Login incorrect.");
	  return;
	}
    }

  /* XXX: Compare only shell base name to "uucico"?
   * Calling execl(uucico_location) would still use
   * the only acceptable binary.  */
  if (strcmp (pw->pw_shell, uucico_location))
    {
      fprintf (stderr, "Login incorrect.");
      return;
    }

  alarm (0);
  snprintf (Username, sizeof (Username), "USER=%s", user);
  snprintf (Logname, sizeof (Logname), "LOGNAME=%s", user);
  dologin (pw, sap, salen);
  setgid (pw->pw_gid);
#ifdef HAVE_INITGROUPS
  initgroups (pw->pw_name, pw->pw_gid);
#endif
  if (chdir (pw->pw_dir) < 0)
    {
      fprintf (stderr, "Login incorrect.");
      return;
    }
  setuid (pw->pw_uid);
  execl (uucico_location, "uucico", NULL);
  perror ("uucico server: execl");
}

void
dologout (void)
{
  int pid;

#ifdef HAVE_WAITPID
  while ((pid = waitpid (-1, 0, WNOHANG)) > 0)
#else
# ifdef HAVE_WAIT3
  while ((pid = wait3 (0, WNOHANG, 0)) > 0)
# else
  while ((pid = wait (0)) > 0)
# endif	/* HAVE_WAIT3 */
#endif /* HAVE_WAITPID */
    {
      char line[100];
      sprintf (line, "uucp%.4d", (int) pid);
#ifdef HAVE_LOGWTMPX
      logwtmpx (line, "", "", 0, DEAD_PROCESS);
#elif defined HAVE_LOGWTMP
      logwtmp (line, "", "");
#elif defined HAVE_PUTUTXLINE
      {
	/* Novelty in FreeBSD 9.0.  */
	struct utmpx ut;
	struct timeval now;

	ut.ut_type = DEAD_PROCESS;
	ut.ut_pid = pid;
	strncpy (ut.ut_line, line, sizeof (ut.ut_line));
	memset (ut.ut_user, 0, sizeof (ut.ut_user));
	memset (ut.ut_host, 0, sizeof (ut.ut_host));
# ifdef HAVE_STRUCT_UTMPX_UT_SYSLEN
	ut.ut_syslen = 1;
# endif
	gettimeofday (&now, NULL);
	ut.ut_tv.tv_sec = now.tv_sec;
	ut.ut_tv.tv_usec = now.tv_usec;
	pututxline (&ut);
      }
#endif /* HAVE_PUTUTXLINE && !HAVE_LOGWTMPX && !HAVE_LOGWTMP */
    }
}

# define SCPYN(a, b)	strncpy(a, b, sizeof (a) - 1); (a)[sizeof (a) - 1] = 0

/*
 * Record login in wtmp file.
 */
void
dologin (struct passwd *pw, struct sockaddr *sap, socklen_t salen)
{
  char line[NI_MAXHOST]; /* remote is copied here later on */
#if defined PATH_LASTLOG && defined HAVE_STRUCT_LASTLOG
  int f;
#endif
#if HAVE_DECL_GETNAMEINFO
  char remotehost[NI_MAXHOST];

  if (getnameinfo (sap, salen, remotehost, sizeof (remotehost),
		   NULL, 0, 0))
    (void) getnameinfo (sap, salen, remotehost, sizeof (remotehost),
			NULL, 0, NI_NUMERICHOST);
#else
  char remotehost[64];
  struct hostent *hp;
  void *addr;
  socklen_t addrlen;

  switch (sap->sa_family)
    {
#ifdef IPV6
    case AF_INET6:
      addr = (void *) &(((struct sockaddr_in6 *) sap)->sin6_addr);
      addrlen = sizeof (struct in6_addr);
      break;
#endif
    case AF_INET:
    default:
      addr = (void *) &(((struct sockaddr_in *) sap)->sin_addr);
      addrlen = sizeof (struct in_addr);
      break;
    }

  (void) salen;		/* Silence warning.  */
  hp = gethostbyaddr (addr, addrlen, sap->sa_family);

  if (hp)
    {
      SCPYN (remotehost, hp->h_name);
      endhostent ();
    }
  else
    {
      remotehost[0] = '\0';
      (void) inet_ntop (sap->sa_family, addr,
			remotehost, sizeof (remotehost));
    }
#endif

  sprintf (line, "uucp%.4d", (int) getpid ());

#ifdef HAVE_LOGWTMPX
  logwtmpx (line, pw->pw_name, remotehost, 0, USER_PROCESS);
#elif defined HAVE_LOGWTMP
  logwtmp (line, pw->pw_name, remotehost);
#elif defined HAVE_PUTUTXLINE
  {
    /* Novelty in FreeBSD 9.0.  */
    struct utmpx ut;
    struct timeval now;

    ut.ut_type = USER_PROCESS;
    ut.ut_pid = getpid();
    SCPYN (ut.ut_line, line);
    SCPYN (ut.ut_user, pw->pw_name);
    SCPYN (ut.ut_host, remotehost);
# ifdef HAVE_STRUCT_UTMPX_UT_SYSLEN
    if (strlen (remotehost) < sizeof (ut.ut_host))
      ut.ut_syslen = strlen (remotehost) + 1;
    else
      {
	ut.ut_host[sizeof (ut.ut_host) - 1] = '\0';
	ut.ut_syslen = sizeof (ut.ut_host);
      }
# endif
    gettimeofday (&now, NULL);
    ut.ut_tv.tv_sec = now.tv_sec;
    ut.ut_tv.tv_usec = now.tv_usec;
    pututxline (&ut);
  }
#endif /* HAVE_PUTUTXLINE && !HAVE_LOGWTMPX && !HAVE_LOGWTMP */

#if defined PATH_LASTLOG && defined HAVE_STRUCT_LASTLOG
  f = open (PATH_LASTLOG, O_RDWR);
  if (f >= 0)
    {
      struct lastlog ll;
      time_t t;

      time (&t);
      ll.ll_time = t;
      lseek (f, (long) pw->pw_uid * sizeof (struct lastlog), 0);
      SCPYN (line, remotehost);
      SCPYN (ll.ll_line, line);
      SCPYN (ll.ll_host, remotehost);
      write (f, (char *) &ll, sizeof (ll));
      close (f);
    }
#endif
}
