1  /*
       2   * pam_rhosts module
       3   *
       4   * Redistribution and use in source and binary forms, with or without
       5   * modification, are permitted provided that the following conditions
       6   * are met:
       7   * 1. Redistributions of source code must retain the above copyright
       8   *    notice, and the entire permission notice in its entirety,
       9   *    including the disclaimer of warranties.
      10   * 2. Redistributions in binary form must reproduce the above copyright
      11   *    notice, this list of conditions and the following disclaimer in the
      12   *    documentation and/or other materials provided with the distribution.
      13   * 3. The name of the author may not be used to endorse or promote
      14   *    products derived from this software without specific prior
      15   *    written permission.
      16   *
      17   * ALTERNATIVELY, this product may be distributed under the terms of
      18   * the GNU Public License, in which case the provisions of the GPL are
      19   * required INSTEAD OF the above restrictions.  (This clause is
      20   * necessary due to a potential bad interaction between the GPL and
      21   * the restrictions contained in a BSD-style copyright.)
      22   *
      23   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
      24   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
      25   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
      26   * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
      27   * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
      28   * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
      29   * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
      30   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
      31   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
      32   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
      33   * OF THE POSSIBILITY OF SUCH DAMAGE.
      34   */
      35  #include "config.h"
      36  
      37  #include <pwd.h>
      38  #include <netdb.h>
      39  #include <string.h>
      40  #include <stdlib.h>
      41  #include <syslog.h>
      42  
      43  #include <security/pam_modules.h>
      44  #include <security/pam_modutil.h>
      45  #include <security/pam_ext.h>
      46  #include "pam_inline.h"
      47  
      48  int pam_sm_authenticate (pam_handle_t *pamh, int flags, int argc,
      49  			 const char **argv)
      50  {
      51      const char *luser = NULL;
      52      const char *ruser = NULL, *rhost = NULL;
      53      const char *opt_superuser = NULL;
      54      const void *c_void;
      55      int opt_debug = 0;
      56      int opt_silent;
      57      int as_root;
      58      int retval;
      59  
      60      opt_silent = flags & PAM_SILENT;
      61  
      62      while (argc-- > 0) {
      63        const char *str;
      64  
      65        if (strcmp(*argv, "debug") == 0)
      66  	opt_debug = 1;
      67        else if (strcmp (*argv, "silent") == 0 || strcmp(*argv, "suppress") == 0)
      68  	opt_silent = 1;
      69        else if ((str = pam_str_skip_prefix(*argv, "superuser=")) != NULL)
      70  	opt_superuser = str;
      71        else
      72  	pam_syslog(pamh, LOG_WARNING, "unrecognized option '%s'", *argv);
      73  
      74        ++argv;
      75      }
      76  
      77      retval = pam_get_item (pamh, PAM_RHOST, &c_void);
      78      if (retval != PAM_SUCCESS) {
      79        pam_syslog(pamh, LOG_ERR, "could not get the remote host name");
      80        return retval;
      81      }
      82      rhost = c_void;
      83  
      84      retval = pam_get_item(pamh, PAM_RUSER, &c_void);
      85      ruser = c_void;
      86      if (retval != PAM_SUCCESS) {
      87        pam_syslog(pamh, LOG_ERR, "could not get the remote username");
      88        return retval;
      89      }
      90  
      91      retval = pam_get_user(pamh, &luser, NULL);
      92      if (retval != PAM_SUCCESS) {
      93        pam_syslog(pamh, LOG_NOTICE, "cannot determine local user name: %s",
      94  		 pam_strerror(pamh, retval));
      95        return retval;
      96      }
      97  
      98      if (rhost == NULL || ruser == NULL)
      99        return PAM_AUTH_ERR;
     100  
     101      if (opt_superuser && strcmp(opt_superuser, luser) == 0)
     102        as_root = 1;
     103      else {
     104        struct passwd *lpwd;
     105  
     106        lpwd = pam_modutil_getpwnam(pamh, luser);
     107        if (lpwd == NULL) {
     108  	if (opt_debug)
     109  	  /* don't print by default, could be the user's password */
     110  	  pam_syslog(pamh, LOG_DEBUG,
     111  		     "user '%s' unknown to this system", luser);
     112  	return PAM_USER_UNKNOWN;
     113  
     114        }
     115        as_root = (lpwd->pw_uid == 0);
     116      }
     117  
     118  #ifdef HAVE_RUSEROK_AF
     119      retval = ruserok_af (rhost, as_root, ruser, luser, PF_UNSPEC);
     120  #else
     121      retval = ruserok (rhost, as_root, ruser, luser);
     122  #endif
     123      if (retval != 0) {
     124        if (!opt_silent || opt_debug)
     125  	pam_syslog(pamh, LOG_WARNING, "denied access to %s@%s as %s",
     126  		   ruser, rhost, luser);
     127        return PAM_AUTH_ERR;
     128      } else {
     129        if (!opt_silent || opt_debug)
     130  	pam_syslog(pamh, LOG_NOTICE, "allowed access to %s@%s as %s",
     131  		   ruser, rhost, luser);
     132        return PAM_SUCCESS;
     133      }
     134  }
     135  
     136  
     137  int
     138  pam_sm_setcred (pam_handle_t *pamh UNUSED, int flags UNUSED,
     139  		int argc UNUSED, const char **argv UNUSED)
     140  {
     141    return PAM_SUCCESS;
     142  }