iruserok.c

压缩包中包含LINUX下多个命令的源码

/* Based on the rcmd.c.new file distributed with linux libc 5.4.19
   Adapted to inetutils by Bernhard Rosenkraenzer <[e-mail]>

   Note that a lot in this file is superfluous; hopefully it won't be a
   problem for systems that need it for iruserok &c....  */
/*
 * Copyright (c) 1983, 1993, 1994
 *	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.
 * 4. 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.
 */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <pwd.h>
#include <sys/file.h>
#include <signal.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <sys/param.h>
#include <sys/socket.h>
#ifdef HAVE_MALLOC_H
#include <malloc.h>
#endif
#if defined(STDC_HEADERS) || defined(HAVE_STDLIB_H)
#include <stdlib.h>
#endif
#ifdef HAVE_STRING_H
# include <string.h>
#endif
#include <netinet/in.h>
#ifdef HAVE_ARPA_NAMESER_H
# include <arpa/nameser.h>
#endif
#include <netdb.h>
#include <unistd.h>
#include <ctype.h>
#include <stdio.h>
#include <errno.h>
#ifdef TIME_WITH_SYS_TIME
# include <sys/time.h>
# include <time.h>
#else
# ifdef HAVE_SYS_TIME_H
#  include <sys/time.h>
# else
#  include <time.h>
# endif
#endif
#include <resolv.h>

static int __ivaliduser __P ((FILE *hostf, u_long raddr,
			      const char *luser, const char *ruser));
static int __icheckhost __P ((u_long raddr, register char *lhost));

int     __check_rhosts_file = 1;
char    *__rcmd_errstr;

/*
 * New .rhosts strategy: We are passed an ip address. We spin through
 * hosts.equiv and .rhosts looking for a match. When the .rhosts only
 * has ip addresses, we don't have to trust a nameserver.  When it
 * contains hostnames, we spin through the list of addresses the nameserver
 * gives us and look for a match.
 *
 * Returns 0 if ok, -1 if not ok.
 */
int
iruserok (u_long raddr, int superuser, const char *ruser, const char *luser)
{
  register char *cp;
  struct stat sbuf;
  struct passwd *pwd;
  FILE *hostf;
  uid_t uid;
  int first = 1;
  char *pbuf;

  first = 1;
  hostf = superuser ? NULL : fopen (PATH_HEQUIV, "r");
 again:
  if (hostf)
    {
      if (__ivaliduser (hostf, raddr, luser, ruser) == 0)
	{
	  (void) fclose (hostf);
	  return 0;
	}
      (void) fclose (hostf);
  }
  if (first == 1 && (__check_rhosts_file || superuser))
    {
      first = 0;
      pwd = getpwnam (luser);
      if (pwd == NULL)
	return -1;

      pbuf = malloc (strlen (pwd->pw_dir) + sizeof "/.rhosts");
      if (! pbuf)
	{
	  errno = ENOMEM;
	  return -1;
	}
      strcpy (pbuf, pwd->pw_dir);
      strcat (pbuf, "/.rhosts");

      /*
       * Change effective uid while opening .rhosts.  If root and
       * reading an NFS mounted file system, can't read files that
       * are protected read/write owner only.
       */
      uid = geteuid();
      (void)seteuid (pwd->pw_uid);
      hostf = fopen (pbuf, "r");
      (void)seteuid (uid);

      if (hostf == NULL)
	return -1;
      /*
       * If not a regular file, or is owned by someone other than
       * user or root or if writeable by anyone but the owner, quit.
       */
      cp = NULL;
      if (lstat (pbuf, &sbuf) < 0)
	cp = ".rhosts not regular file";
      else if (!S_ISREG(sbuf.st_mode))
	cp = ".rhosts not regular file";
      else if (fstat (fileno(hostf), &sbuf) < 0)
	cp = ".rhosts fstat failed";
      else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid)
	cp = "bad .rhosts owner";
      else if (sbuf.st_mode & (S_IWGRP|S_IWOTH))
	cp = ".rhosts writeable by other than owner";
      /* If there were any problems, quit. */
      if (cp)
	{
	  __rcmd_errstr = cp;
	  fclose (hostf);
	  return -1;
	}
      goto again;
    }
  return -1;
}

/*
 * XXX
 * Don't make static, used by lpd(8).
 * We are not distributing lpd make it static
 * alain.
 *
 * Returns 0 if ok, -1 if not ok.
 */
static int
__ivaliduser (FILE *hostf, u_long raddr, const char *luser, const char *ruser)
{
  size_t buf_offs = 0;
  size_t buf_len = 256;
  char *buf = malloc (buf_len);

  if (! buf)
    return -1;

  while (fgets(buf + buf_offs, buf_len - buf_offs, hostf))
    {
      int ch;
      register char *user, *p;

      if (strchr(buf + buf_offs, '\n') == NULL)
	{
	  /* No newline yet, read some more.  */
	  buf_offs += strlen (buf + buf_offs);

	  if (buf_offs >= buf_len - 1)
	    {
	      /* Make more room in BUF.  */
	      char *new_buf;

	      buf_len += buf_len;
	      new_buf = realloc (buf, buf_len);

	      if (! new_buf)
		{
		  free (buf);
		  return -1;
		}

	      buf = new_buf;
	    }

	  continue;
	}

      buf_offs = 0;	/* Start at beginning next time around.  */

      p = buf;
      while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0')
	{
	  /* *p = isupper(*p) ? tolower(*p) : *p;  -- Uli */
	  *p = tolower (*p);	/* works for linux libc */
	  p++;
	}
      if (*p == ' ' || *p == '\t')
	{
	  *p++ = '\0';
	  while (*p == ' ' || *p == '\t')
	    p++;
	  user = p;
	  while (*p != '\n' && *p != ' ' &&
		 *p != '\t' && *p != '\0')
	    p++;
	} else
	  user = p;
      *p = '\0';

      if (__icheckhost (raddr, buf) && !strcmp (ruser, *user ? user : luser))
	{
	  free (buf);
	  return 0;
	}
    }

  free (buf);

  return -1;
}

/*
 * Returns "true" if match, 0 if no match.
 */
static int
__icheckhost (u_long raddr, register char *lhost)
{
  register struct hostent *hp;
  register u_long laddr;
  register char **pp;

  /* Try for raw ip address first. */
  if (isdigit (*lhost) && (long)(laddr = inet_addr (lhost)) != -1)
    return (raddr == laddr);

  /* Better be a hostname. */
  hp = gethostbyname (lhost);
  if (hp == NULL)
    return 0;

  /* Spin through ip addresses. */
#ifdef HAVE_STRUCT_HOSTENT_H_ADDR_LIST
  for (pp = hp->h_addr_list; *pp; ++pp)
    if (!memcmp (&raddr, *pp, sizeof (u_long)))
      return 1;
#else
  if (!memcmp (&raddr, hp->h_addr, sizeof (u_long)))
    return 1;
#endif

  /* No match. */
  return 0;
}