samba-mirror/source3/smbd/uid.c

/* 
   Unix SMB/Netbios implementation.
   Version 1.9.
   uid/user handling
   Copyright (C) Andrew Tridgell 1992-1995
   
   This program 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 2 of the License, or
   (at your option) any later version.
   
   This program 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, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "includes.h"
#include "loadparm.h"

extern int DEBUGLEVEL;

extern connection_struct Connections[];

static int initial_uid;
static int initial_gid;
static int old_umask = 022;

static pstring OriginalDir;

/* what user is current? */
struct current_user current_user;

/****************************************************************************
initialise the uid routines
****************************************************************************/
void init_uid(void)
{
  initial_uid = current_user.uid = geteuid();
  initial_gid = current_user.gid = getegid();

  if (initial_gid != 0 && initial_uid == 0)
    {
#ifdef HPUX
      setresgid(0,0,0);
#else
      setgid(0);
      setegid(0);
#endif
    }

  initial_uid = geteuid();
  initial_gid = getegid();

  current_user.cnum = -1;

  GetWd(OriginalDir);
}


/****************************************************************************
  become the specified uid 
****************************************************************************/
static BOOL become_uid(int uid)
{
  if (initial_uid != 0)
    return(True);

#ifdef AIX
  {
    /* AIX 3 stuff - inspired by a code fragment in wu-ftpd */
    priv_t priv;

    priv.pv_priv[0] = 0;
    priv.pv_priv[1] = 0;
    if (setpriv(PRIV_SET|PRIV_INHERITED|PRIV_EFFECTIVE|PRIV_BEQUEATH,
		&priv, sizeof(priv_t)) < 0 ||
	setuidx(ID_REAL|ID_EFFECTIVE, (uid_t)uid) < 0 ||
	seteuid((uid_t)uid) < 0) 
      DEBUG(1,("Can't set uid (AIX3)"));
  }
#endif

#ifdef USE_SETRES
  if (setresuid(-1,uid,-1) != 0)
#elif defined(USE_SETFS)
    if (setfsuid(uid) != 0)
#else
    if ((seteuid(uid) != 0) && 
	(setuid(uid) != 0))
#endif
      {
	DEBUG(0,("Couldn't set uid %d currently set to (%d,%d)\n",
		 uid,getuid(), geteuid()));
	if (uid > 32000)
	  DEBUG(0,("Looks like your OS doesn't like high uid values - try using a different account\n"));
	return(False);
      }

  if (((uid == -1) || (uid == 65535)) && geteuid() != uid) {
    DEBUG(0,("Invalid uid -1. perhaps you have a account with uid 65535?\n"));
    return(False);
  }

  current_user.uid = uid;

  return(True);
}


/****************************************************************************
  become the specified gid
****************************************************************************/
static BOOL become_gid(int gid)
{
  if (initial_uid != 0)
    return(True);
  
#ifdef USE_SETRES 
  if (setresgid(-1,gid,-1) != 0)
#elif defined(USE_SETFS)
  if (setfsgid(gid) != 0)
#else
  if (setgid(gid) != 0)
#endif
      {
	DEBUG(0,("Couldn't set gid %d currently set to (%d,%d)\n",
		 gid,getgid(),getegid()));
	if (gid > 32000)
	  DEBUG(0,("Looks like your OS doesn't like high gid values - try using a different account\n"));
	return(False);
      }

  current_user.gid = gid;

  return(True);
}


/****************************************************************************
  become the specified uid and gid
****************************************************************************/
static BOOL become_id(int uid,int gid)
{
  return(become_gid(gid) && become_uid(uid));
}

/****************************************************************************
become the guest user
****************************************************************************/
BOOL become_guest(void)
{
  BOOL ret;
  static struct passwd *pass=NULL;

  if (initial_uid != 0) 
    return(True);

  if (!pass)
    pass = Get_Pwnam(lp_guestaccount(-1),True);
  if (!pass) return(False);

  ret = become_id(pass->pw_uid,pass->pw_gid);

  if (!ret)
    DEBUG(1,("Failed to become guest. Invalid guest account?\n"));

  current_user.cnum = -2;

  return(ret);
}

/*******************************************************************
check if a username is OK
********************************************************************/
static BOOL check_user_ok(int cnum,user_struct *vuser,int snum)
{
  int i;
  for (i=0;i<Connections[cnum].uid_cache.entries;i++)
    if (Connections[cnum].uid_cache.list[i] == vuser->uid) return(True);

  if (!user_ok(vuser->name,snum)) return(False);

  i = Connections[cnum].uid_cache.entries % UID_CACHE_SIZE;
  Connections[cnum].uid_cache.list[i] = vuser->uid;

  if (Connections[cnum].uid_cache.entries < UID_CACHE_SIZE)
    Connections[cnum].uid_cache.entries++;

  return(True);
}


/****************************************************************************
  become the user of a connection number
****************************************************************************/
BOOL become_user(int cnum, int uid)
{
  int new_umask;
  user_struct *vuser;
  int snum,gid;
  int id = uid;

  if (current_user.cnum == cnum && current_user.id == id) {
    DEBUG(4,("Skipping become_user - already user\n"));
    return(True);
  }

  unbecome_user();

  if (!OPEN_CNUM(cnum)) {
    DEBUG(2,("Connection %d not open\n",cnum));
    return(False);
  }

  snum = Connections[cnum].service;

  if (Connections[cnum].force_user || 
      lp_security() == SEC_SHARE ||
      !(vuser = get_valid_user_struct(uid)) ||
      !check_user_ok(cnum,vuser,snum)) {
    uid = Connections[cnum].uid;
    gid = Connections[cnum].gid;
    current_user.groups = Connections[cnum].groups;
    current_user.igroups = Connections[cnum].igroups;
    current_user.ngroups = Connections[cnum].ngroups;
  } else {
    if (!vuser) {
      DEBUG(2,("Invalid vuid used %d\n",uid));
      return(False);
    }
    uid = vuser->uid;
    if(!*lp_force_group(snum))
      gid = vuser->gid;
    else
      gid = Connections[cnum].gid;
    current_user.groups = vuser->user_groups;
    current_user.igroups = vuser->user_igroups;
    current_user.ngroups = vuser->user_ngroups;
  }

  if (initial_uid == 0)
    {
      if (!become_gid(gid)) return(False);

#ifndef NO_SETGROUPS      
      if (!IS_IPC(cnum)) {
	/* groups stuff added by ih/wreu */
	if (current_user.ngroups > 0)
	  if (setgroups(current_user.ngroups,current_user.groups)<0)
	    DEBUG(0,("setgroups call failed!\n"));
      }
#endif

      if (!Connections[cnum].admin_user && !become_uid(uid))
	return(False);
    }

  new_umask = 0777 & ~CREATE_MODE(cnum);
  old_umask = umask(new_umask);

  current_user.cnum = cnum;
  current_user.id = id;
  
  DEBUG(5,("become_user uid=(%d,%d) gid=(%d,%d) new_umask=0%o\n",
	   getuid(),geteuid(),getgid(),getegid(),new_umask));
  
  return(True);
}

/****************************************************************************
  unbecome the user of a connection number
****************************************************************************/
BOOL unbecome_user(void )
{
  if (current_user.cnum == -1)
    return(False);

  ChDir(OriginalDir);

  umask(old_umask);

  if (initial_uid == 0)
    {
#ifdef USE_SETRES
      setresuid(-1,getuid(),-1);
      setresgid(-1,getgid(),-1);
#elif defined(USE_SETFS)
      setfsuid(initial_uid);
      setfsgid(initial_gid);
#else
      if (seteuid(initial_uid) != 0) 
	setuid(initial_uid);
      setgid(initial_gid);
#endif
    }
#ifdef NO_EID
  if (initial_uid == 0)
    DEBUG(2,("Running with no EID\n"));
  initial_uid = getuid();
  initial_gid = getgid();
#else
  if (geteuid() != initial_uid)
    {
      DEBUG(0,("Warning: You appear to have a trapdoor uid system\n"));
      initial_uid = geteuid();
    }
  if (getegid() != initial_gid)
    {
      DEBUG(0,("Warning: You appear to have a trapdoor gid system\n"));
      initial_gid = getegid();
    }
#endif

  current_user.uid = initial_uid;
  current_user.gid = initial_gid;
  
  if (ChDir(OriginalDir) != 0)
    DEBUG(0,("%s chdir(%s) failed in unbecome_user\n",
	     timestring(),OriginalDir));  

  DEBUG(5,("unbecome_user now uid=(%d,%d) gid=(%d,%d)\n",
	getuid(),geteuid(),getgid(),getegid()));

  current_user.cnum = -1;

  return(True);
}


/****************************************************************************
run a command via system() using smbrun, being careful about uid/gid handling
****************************************************************************/
int smbrun(char *cmd,char *outfile)
{
  int ret;
  pstring syscmd;  
  char *path = lp_smbrun();

  if (!file_exist(path,NULL))
    {
      DEBUG(0,("SMBRUN ERROR: Can't find %s. Installation problem?\n",path));
      return(1);
    }

  sprintf(syscmd,"%s %d %d \"(%s 2>&1) > %s\"",
	  path,current_user.uid,current_user.gid,cmd,
	  outfile?outfile:"/dev/null");

  DEBUG(5,("smbrun - running %s ",syscmd));
  ret = system(syscmd);
  DEBUG(5,("gave %d\n",ret));
  return(ret);
}