niceSOFT/inetutils

src/rexecd.c
376 строк9 KB
Alfred M. Szmidt
Fix prohibit_dirent_without_use, sc_unsigned_short, sc_unsigned_long sc_unsigned_char checks.
30 дек 2011, 21:49
30 дек 2011, 21:491a343be
/*
  Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
  2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 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) 1983, 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.
 */

#include <config.h>

#include <sys/types.h>
#include <sys/param.h>
#include <sys/ioctl.h>
#ifdef HAVE_SYS_FILIO_H
# include <sys/filio.h>
#endif
#include <sys/socket.h>
#include <sys/time.h>
#include <time.h>

#include <netinet/in.h>

#include <errno.h>
#include <netdb.h>
#include <pwd.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <grp.h>
#ifdef HAVE_CRYPT_H
# include <crypt.h>
#endif
#include <sys/select.h>
#include <stdarg.h>
#ifdef HAVE_SHADOW_H
# include <shadow.h>
#endif
#include <progname.h>
#include <argp.h>
#include <error.h>
#include "libinetutils.h"

void die (int code, const char *fmt, ...);
int doit (int f, struct sockaddr_in *fromp);

const char doc[] = "remote execution daemon";

static struct argp argp = {
  NULL,
  NULL,
  NULL,
  doc,
  NULL,
  NULL,
  NULL
};

/*
 * remote execute server:
 *	username\0
 *	password\0
 *	command\0
 *	data
 */
int
main (int argc, char **argv)
{
  struct sockaddr_in from;
  socklen_t fromlen;
  int sockfd = STDIN_FILENO;
  int index;

  set_program_name (argv[0]);

  iu_argp_init ("rexecd", default_program_authors);
  argp_parse (&argp, argc, argv, 0, &index, NULL);
  if (argc > index)
    error (EXIT_FAILURE, 0, "surplus arguments");

  fromlen = sizeof (from);
  if (getpeername (sockfd, (struct sockaddr *) &from, &fromlen) < 0)
    error (EXIT_FAILURE, errno, "getpeername");
  doit (sockfd, &from);
  exit (EXIT_SUCCESS);
}

char username[20] = "USER=";
char logname[23] = "LOGNAME=";
char homedir[64] = "HOME=";
char shell[64] = "SHELL=";
char path[sizeof (PATH_DEFPATH) + sizeof ("PATH=")] = "PATH=";
char *envinit[] = { homedir, shell, path, username, logname, 0 };
extern char **environ;

#ifdef HAVE_STRUCT_SOCKADDR_IN_SIN_LEN
struct sockaddr_in a_sin = { sizeof (a_sin), AF_INET };
#else
struct sockaddr_in a_sin = { AF_INET };
#endif

char *getstr (const char *);

static char *
get_user_password (struct passwd *pwd)
{
  char *pw_text = pwd->pw_passwd;
#ifdef HAVE_SHADOW_H
  struct spwd *spwd = getspnam (pwd->pw_name);
  if (spwd)
    pw_text = spwd->sp_pwdp;
#endif
  return pw_text;
}

int
doit (int f, struct sockaddr_in *fromp)
{
  char *cmdbuf, *cp, *namep;
  char *user, *pass, *pw_password;
  struct passwd *pwd;
  int s;
  unsigned short port;
  int pv[2], pid, cc;
  fd_set readfrom, ready;
  char buf[BUFSIZ], sig;
  int one = 1;

  signal (SIGINT, SIG_DFL);
  signal (SIGQUIT, SIG_DFL);
  signal (SIGTERM, SIG_DFL);
#ifdef DEBUG
  {
    int t = open (_PATH_TTY, O_RDWR);
    if (t >= 0)
      {
	ioctl (t, TIOCNOTTY, (char *) 0);
	close (t);
      }
  }
#endif
  if (f != STDIN_FILENO)
    {
      dup2 (f, STDIN_FILENO);
      dup2 (f, STDOUT_FILENO);
      dup2 (f, STDERR_FILENO);
    }

  alarm (60);
  port = 0;
  for (;;)
    {
      char c;
      if (read (f, &c, 1) != 1)
	exit (EXIT_FAILURE);
      if (c == 0)
	break;
      port = port * 10 + c - '0';
    }
  alarm (0);
  if (port != 0)
    {
      s = socket (AF_INET, SOCK_STREAM, 0);
      if (s < 0)
	exit (EXIT_FAILURE);
      if (bind (s, (struct sockaddr *) &a_sin, sizeof (a_sin)) < 0)
	exit (EXIT_FAILURE);
      alarm (60);
      fromp->sin_port = htons (port);
      if (connect (s, (struct sockaddr *) fromp, sizeof (*fromp)) < 0)
	exit (EXIT_FAILURE);
      alarm (0);
    }

  user = getstr ("username");
  pass = getstr ("password");
  cmdbuf = getstr ("command");

  setpwent ();
  pwd = getpwnam (user);
  if (pwd == NULL)
    die (1, "Login incorrect.");

  endpwent ();
  pw_password = get_user_password (pwd);
  if (*pw_password != '\0')
    {
      namep = crypt (pass, pw_password);
      if (strcmp (namep, pw_password))
	die (1, "Password incorrect.");
    }
  write (STDERR_FILENO, "\0", 1);
  if (port)
    {
      pipe (pv);
      pid = fork ();
      if (pid == -1)
	die (1, "Try again.");

      if (pid)
	{
	  close (STDIN_FILENO);
	  close (STDOUT_FILENO);
	  close (STDERR_FILENO);
	  close (f);
	  close (pv[1]);
	  FD_ZERO (&readfrom);
	  FD_SET (s, &readfrom);
	  FD_SET (pv[0], &readfrom);
	  ioctl (pv[1], FIONBIO, (char *) &one);
	  /* should set s nbio! */
	  do
	    {
	      int maxfd = s;
	      ready = readfrom;
	      if (pv[0] > maxfd)
		maxfd = pv[0];
	      select (maxfd + 1, (fd_set *) & ready,
		      (fd_set *) NULL, (fd_set *) NULL,
		      (struct timeval *) NULL);
	      if (FD_ISSET (s, &ready))
		{
		  if (read (s, &sig, 1) <= 0)
		    FD_CLR (s, &readfrom);
		  else
		    killpg (pid, sig);
		}
	      if (FD_ISSET (pv[0], &ready))
		{
		  cc = read (pv[0], buf, sizeof (buf));
		  if (cc <= 0)
		    {
		      shutdown (s, 1 + 1);
		      FD_CLR (pv[0], &readfrom);
		    }
		  else
		    write (s, buf, cc);
		}
	    }
	  while (FD_ISSET (pv[0], &readfrom) || FD_ISSET (s, &readfrom));
	  exit (EXIT_SUCCESS);
	}
      setpgid (0, getpid ());
      close (s);
      close (pv[0]);
      dup2 (pv[1], STDERR_FILENO);
    }
  if (*pwd->pw_shell == '\0')
    pwd->pw_shell = PATH_BSHELL;
  if (f > 2)
    close (f);
  if (setegid ((gid_t) pwd->pw_gid) < 0)
    error (EXIT_FAILURE, errno, "failed to set additional groups");
  if (setgid ((gid_t) pwd->pw_gid) < 0)
    error (EXIT_FAILURE, errno, "failed to set group-ID");
#ifdef HAVE_INITGROUPS
  if (initgroups (pwd->pw_name, pwd->pw_gid) < 0)
    error (EXIT_FAILURE, errno,
	   "failed to initialize the supplementary group access list");
#endif
  if (setuid ((uid_t) pwd->pw_uid) < 0)
    error (EXIT_FAILURE, errno, "failed to set user-ID");
  if (chdir (pwd->pw_dir) < 0)
    die (1, "No remote directory.");
  strcat (path, PATH_DEFPATH);
  environ = envinit;
  strncat (homedir, pwd->pw_dir, sizeof (homedir) - 6);
  strncat (shell, pwd->pw_shell, sizeof (shell) - 7);
  strncat (username, pwd->pw_name, sizeof (username) - 6);
  cp = strrchr (pwd->pw_shell, '/');
  if (cp)
    cp++;
  else
    cp = pwd->pw_shell;
  execl (pwd->pw_shell, cp, "-c", cmdbuf, NULL);
  error (EXIT_FAILURE, errno, "executing %s", pwd->pw_shell);

  return -1;
}

void
die (int code, const char *fmt, ...)
{
  va_list ap;
  char buf[BUFSIZ];
  int n;

  va_start (ap, fmt);
  buf[0] = 1;
  n = snprintf (buf + 1, sizeof buf - 1, fmt, ap);
  va_end (ap);
  if (n > sizeof buf - 1)
    n = sizeof buf - 1;
  buf[n] = '\n';
  write (STDERR_FILENO, buf, n);
}

char *
getstr (const char *err)
{
  size_t buf_len = 100;
  char *buf = malloc (buf_len), *end = buf;

  if (!buf)
    die (1, "Out of space reading %s", err);

  do
    {
      /* Oh this is efficient, oh yes.  [But what can be done?] */
      int rd = read (STDIN_FILENO, end, 1);
      if (rd <= 0)
	{
	  if (rd == 0)
	    die (1, "EOF reading %s", err);
	  else
	    error (EXIT_FAILURE, 0, "%s", err);
	}

      end += rd;
      if ((buf + buf_len - end) < (buf_len >> 3))
	{
	  /* Not very much room left in our buffer, grow it. */
	  size_t end_offs = end - buf;
	  buf_len += buf_len;
	  buf = realloc (buf, buf_len);
	  if (!buf)
	    die (1, "Out of space reading %s", err);
	  end = buf + end_offs;
	}
    }
  while (*(end - 1));

  return buf;
}