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/* wydawca - automatic release submission daemon
   Copyright (C) 2007, 2009, 2010 Sergey Poznyakoff

   Wydawca 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.

   Wydawca 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 wydawca. If not, see <http://www.gnu.org/licenses/>. */

#include "wydawca.h"

int
wydawca_userprivs (uid_t uid, gid_t gid, gid_t *grplist, size_t ngrp)
{
  int rc = 0;

  if (uid == 0)
    return 0;
  
  /* Reset group permissions */
  if (geteuid () == 0 && setgroups (ngrp, grplist))
    {
      logmsg (LOG_CRIT, "setgroups(%lu, %lu...): %s",
	      (unsigned long)ngrp, (unsigned long)grplist[0],
	      strerror (errno));
      return rc;
    }
	
  /* Switch to the user's gid. On some OSes the effective gid must
     be reset first */

#if defined(HAVE_SETEGID)
  if ((rc = setegid (gid)) < 0)
    logmsg (LOG_CRIT, "setegid(%lu): %s",
	    (unsigned long) gid, strerror (errno));
#elif defined(HAVE_SETREGID)
  if ((rc = setregid (gid, gid)) < 0)
    logmsg (LOG_CRIT, "setregid(%lu,%lu)d: %s",
	    (unsigned long) gid, (unsigned long) gid, strerror (errno));
#elif defined(HAVE_SETRESGID)
  if ((rc = setresgid (gid, gid, gid)) < 0)
    logmsg (LOG_CRIT, "setresgid(%lu,%lu,%lu): %s",
	    (unsigned long) gid, (unsigned long) gid,
	    (unsigned long) gid,
	    strerror (errno));
#endif

  if (rc == 0 && gid != 0)
    {
      if ((rc = setgid (gid)) < 0 && getegid () != gid) 
	logmsg (LOG_CRIT, "setgid(%lu): %s",
		(unsigned long) gid, strerror (errno));
      if (rc == 0 && getegid () != gid)
	{
	  logmsg (LOG_CRIT, _("cannot set effective gid to %lu"),
		  (unsigned long) gid);
	  rc = 1;
	}
    }

  /* Now reset uid */
  if (rc == 0 && uid != 0)
    {
      uid_t euid;

      if (setuid (uid)
	  || geteuid () != uid
	  || (getuid () != uid
	      && (geteuid () == 0 || getuid () == 0)))
	{
			
#if defined(HAVE_SETREUID)
	  if (geteuid () != uid)
	    {
	      if (setreuid (uid, -1) < 0)
		{ 
		  logmsg (LOG_CRIT, "setreuid(%lu,-1): %s",
			  (unsigned long) uid, strerror (errno));
		  rc = 1;
		}
	      if (setuid (uid) < 0)
		{
		  logmsg (LOG_CRIT, "setreuid(%lu,-1): %s",
			  (unsigned long) uid, strerror (errno));
		  rc = 1;
		}
	    }
	  else
#endif
	    {
	      logmsg (LOG_CRIT, "setuid(%lu): %s",
		      (unsigned long) uid, strerror (errno));
	      rc = 1;
	    }
	}
	
      euid = geteuid ();
      if (uid != 0 && setuid (0) == 0)
	{
	  logmsg (LOG_CRIT, _("seteuid(0) succeeded when it should not"));
	  rc = 1;
	}
      else if (uid != euid && setuid (euid) == 0)
	{
	  logmsg (LOG_CRIT, _("cannot drop non-root setuid privileges"));
	  rc = 1;
	}

    }
  
  return rc;
}

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