Patch from Simo:

[Samba.git] / source / smbd / password.c

/* 
   Unix SMB/Netbios implementation.
   Version 1.9.
   Password and authentication handling
   Copyright (C) Andrew Tridgell 1992-1998
   
   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"

extern int DEBUGLEVEL;
extern int Protocol;
extern struct in_addr ipzero;

/* users from session setup */
static pstring session_users="";

extern pstring global_myname;
extern fstring global_myworkgroup;

/* Data to do lanman1/2 password challenge. */
static unsigned char saved_challenge[8];
static BOOL challenge_sent=False;

/*******************************************************************
Get the next challenge value - no repeats.
********************************************************************/
void generate_next_challenge(char *challenge)
{
#if 0
        /* 
         * Leave this ifdef'd out while we test
         * the new crypto random number generator.
         * JRA.
         */
        unsigned char buf[16];
        static int counter = 0;
        struct timeval tval;
        int v1,v2;

        /* get a sort-of random number */
        GetTimeOfDay(&tval);
        v1 = (counter++) + sys_getpid() + tval.tv_sec;
        v2 = (counter++) * sys_getpid() + tval.tv_usec;
        SIVAL(challenge,0,v1);
        SIVAL(challenge,4,v2);

        /* mash it up with md4 */
        mdfour(buf, (unsigned char *)challenge, 8);
#else
        unsigned char buf[8];

        generate_random_buffer(buf,8,False);
#endif 
        memcpy(saved_challenge, buf, 8);
        memcpy(challenge,buf,8);
        challenge_sent = True;
}

/*******************************************************************
set the last challenge sent, usually from a password server
********************************************************************/
BOOL set_challenge(unsigned char *challenge)
{
  memcpy(saved_challenge,challenge,8);
  challenge_sent = True;
  return(True);
}

/*******************************************************************
get the last challenge sent
********************************************************************/
static BOOL last_challenge(unsigned char *challenge)
{
  if (!challenge_sent) return(False);
  memcpy(challenge,saved_challenge,8);
  return(True);
}

/* this holds info on user ids that are already validated for this VC */
static user_struct *validated_users;
static int next_vuid = VUID_OFFSET;
static int num_validated_vuids;

/****************************************************************************
check if a uid has been validated, and return an pointer to the user_struct
if it has. NULL if not. vuid is biased by an offset. This allows us to
tell random client vuid's (normally zero) from valid vuids.
****************************************************************************/
user_struct *get_valid_user_struct(uint16 vuid)
{
        user_struct *usp;
        int count=0;

        if (vuid == UID_FIELD_INVALID)
                return NULL;

        for (usp=validated_users;usp;usp=usp->next,count++) {
                if (vuid == usp->vuid) {
                        if (count > 10) {
                                DLIST_PROMOTE(validated_users, usp);
                        }
                        return usp;
                }
        }

        return NULL;
}

/****************************************************************************
invalidate a uid
****************************************************************************/
void invalidate_vuid(uint16 vuid)
{
        user_struct *vuser = get_valid_user_struct(vuid);

        if (vuser == NULL)
                return;

        session_yield(vuid);

        DLIST_REMOVE(validated_users, vuser);

        safe_free(vuser->groups);
        delete_nt_token(&vuser->nt_user_token);
        safe_free(vuser);
        num_validated_vuids--;
}

/****************************************************************************
invalidate all vuid entries for this process
****************************************************************************/
void invalidate_all_vuids(void)
{
        user_struct *usp, *next=NULL;

        for (usp=validated_users;usp;usp=next) {
                next = usp->next;
                
                invalidate_vuid(usp->vuid);
        }
}

/****************************************************************************
return a validated username
****************************************************************************/
char *validated_username(uint16 vuid)
{
        user_struct *vuser = get_valid_user_struct(vuid);
        if (vuser == NULL)
                return 0;
        return(vuser->user.unix_name);
}

/****************************************************************************
return a validated domain
****************************************************************************/
char *validated_domain(uint16 vuid)
{
        user_struct *vuser = get_valid_user_struct(vuid);
        if (vuser == NULL)
                return 0;
        return(vuser->user.domain);
}


/****************************************************************************
 Create the SID list for this user.
****************************************************************************/

NT_USER_TOKEN *create_nt_token(uid_t uid, gid_t gid, int ngroups, gid_t *groups, BOOL is_guest)
{
        extern DOM_SID global_sid_World;
        extern DOM_SID global_sid_Network;
        extern DOM_SID global_sid_Builtin_Guests;
        extern DOM_SID global_sid_Authenticated_Users;
        NT_USER_TOKEN *token;
        DOM_SID *psids;
        int i, psid_ndx = 0;
        size_t num_sids = 0;
        fstring sid_str;

        if ((token = (NT_USER_TOKEN *)malloc( sizeof(NT_USER_TOKEN) ) ) == NULL)
                return NULL;

        ZERO_STRUCTP(token);

        /* We always have uid/gid plus World and Network and Authenticated Users or Guest SIDs. */
        num_sids = 5 + ngroups;

        if ((token->user_sids = (DOM_SID *)malloc( num_sids*sizeof(DOM_SID))) == NULL) {
                free(token);
                return NULL;
        }

        psids = token->user_sids;

        /*
         * Note - user SID *MUST* be first in token !
         * se_access_check depends on this.
         */

        uid_to_sid( &psids[psid_ndx++], uid);

        /*
         * Primary group SID is second in token. Convention.
         */

        gid_to_sid( &psids[psid_ndx++], gid);

        /* Now add the group SIDs. */

        for (i = 0; i < ngroups; i++) {
                if (groups[i] != gid) {
                        gid_to_sid( &psids[psid_ndx++], groups[i]);
                }
        }

        /*
         * Finally add the "standard" SIDs.
         * The only difference between guest and "anonymous" (which we
         * don't really support) is the addition of Authenticated_Users.
         */

        sid_copy( &psids[psid_ndx++], &global_sid_World);
        sid_copy( &psids[psid_ndx++], &global_sid_Network);

        if (is_guest)
                sid_copy( &psids[psid_ndx++], &global_sid_Builtin_Guests);
        else
                sid_copy( &psids[psid_ndx++], &global_sid_Authenticated_Users);

        token->num_sids = psid_ndx;

        /* Dump list of sids in token */

        for (i = 0; i < token->num_sids; i++) {
                DEBUG(5, ("user token sid %s\n", 
                          sid_to_string(sid_str, &token->user_sids[i])));
        }

        return token;
}

/****************************************************************************
register a uid/name pair as being valid and that a valid password
has been given. vuid is biased by an offset. This allows us to
tell random client vuid's (normally zero) from valid vuids.
****************************************************************************/

int register_vuid(uid_t uid,gid_t gid, char *unix_name, char *requested_name, 
                  char *domain,BOOL guest)
{
        user_struct *vuser = NULL;
        struct passwd *pwfile; /* for getting real name from passwd file */

        /* Ensure no vuid gets registered in share level security. */
        if(lp_security() == SEC_SHARE)
                return UID_FIELD_INVALID;

        /* Limit allowed vuids to 16bits - VUID_OFFSET. */
        if (num_validated_vuids >= 0xFFFF-VUID_OFFSET)
                return UID_FIELD_INVALID;

        if((vuser = (user_struct *)malloc( sizeof(user_struct) )) == NULL) {
                DEBUG(0,("Failed to malloc users struct!\n"));
                return UID_FIELD_INVALID;
        }

        ZERO_STRUCTP(vuser);

        DEBUG(10,("register_vuid: (%u,%u) %s %s %s guest=%d\n", (unsigned int)uid, (unsigned int)gid,
                                unix_name, requested_name, domain, guest ));

        /* Allocate a free vuid. Yes this is a linear search... :-) */
        while( get_valid_user_struct(next_vuid) != NULL ) {
                next_vuid++;
                /* Check for vuid wrap. */
                if (next_vuid == UID_FIELD_INVALID)
                        next_vuid = VUID_OFFSET;
        }

        DEBUG(10,("register_vuid: allocated vuid = %u\n", (unsigned int)next_vuid ));

        vuser->vuid = next_vuid;
        vuser->uid = uid;
        vuser->gid = gid;
        vuser->guest = guest;
        fstrcpy(vuser->user.unix_name,unix_name);
        fstrcpy(vuser->user.smb_name,requested_name);
        fstrcpy(vuser->user.domain,domain);

        vuser->n_groups = 0;
        vuser->groups  = NULL;

        /* Find all the groups this uid is in and store them. 
                Used by become_user() */
        initialise_groups(unix_name, uid, gid);
        get_current_groups( &vuser->n_groups, &vuser->groups);

        /* Create an NT_USER_TOKEN struct for this user. */
        vuser->nt_user_token = create_nt_token(uid,gid, vuser->n_groups, vuser->groups, guest);

        next_vuid++;
        num_validated_vuids++;

        DLIST_ADD(validated_users, vuser);

        DEBUG(3,("uid %d registered to name %s\n",(int)uid,unix_name));

        DEBUG(3, ("Clearing default real name\n"));
        if ((pwfile=sys_getpwnam(vuser->user.unix_name))!= NULL) {
                DEBUG(3, ("User name: %s\tReal name: %s\n",vuser->user.unix_name,pwfile->pw_gecos));
                fstrcpy(vuser->user.full_name, pwfile->pw_gecos);
        }

        if (!session_claim(vuser->vuid)) {
                DEBUG(1,("Failed to claim session for vuid=%d\n", vuser->vuid));
                invalidate_vuid(vuser->vuid);
                return -1;
        }

        return vuser->vuid;
}


/****************************************************************************
add a name to the session users list
****************************************************************************/
void add_session_user(char *user)
{
  fstring suser;
  StrnCpy(suser,user,sizeof(suser)-1);

  if (!Get_Pwnam(suser,True)) return;

  if (suser && *suser && !in_list(suser,session_users,False))
    {
      if (strlen(suser) + strlen(session_users) + 2 >= sizeof(pstring))
        DEBUG(1,("Too many session users??\n"));
      else
        {
          pstrcat(session_users," ");
          pstrcat(session_users,suser);
        }
    }
}


/****************************************************************************
update the encrypted smbpasswd file from the plaintext username and password
*****************************************************************************/
static BOOL update_smbpassword_file(char *user, char *password)
{
        SAM_ACCOUNT     *sampass = NULL;
        BOOL            ret;
        
        pdb_init_sam(&sampass);
        
        become_root();
        ret = pdb_getsampwnam(sampass, user);
        unbecome_root();

        if(ret == False) {
                DEBUG(0,("pdb_getsampwnam returned NULL\n"));
                pdb_free_sam(sampass);
                return False;
        }

        /*
         * Remove the account disabled flag - we are updating the
         * users password from a login.
         */
        pdb_set_acct_ctrl(sampass, pdb_get_acct_ctrl(sampass) & ~ACB_DISABLED);

        /* Here, the flag is one, because we want to ignore the
           XXXXXXX'd out password */
        ret = change_oem_password( sampass, password, True);
        if (ret == False) {
                DEBUG(3,("change_oem_password returned False\n"));
        }

        pdb_free_sam(sampass);
        return ret;
}

/****************************************************************************
core of smb password checking routine.
****************************************************************************/
BOOL smb_password_check(char *password, unsigned char *part_passwd, unsigned char *c8)
{
  /* Finish the encryption of part_passwd. */
  unsigned char p21[21];
  unsigned char p24[24];

  if (part_passwd == NULL) 
  {
    DEBUG(10,("No password set - allowing access\n"));

    /* No password set - always true ! */
    return 1;
  }

  memset(p21,'\0',21);
  memcpy(p21,part_passwd,16);
  E_P24(p21, c8, p24);
#if DEBUG_PASSWORD
  {
    int i;
    DEBUG(100,("Part password (P16) was |"));
    for(i = 0; i < 16; i++)
      DEBUG(100,("%X ", (unsigned char)part_passwd[i]));
    DEBUG(100,("|\n"));
    DEBUG(100,("Password from client was |"));
    for(i = 0; i < 24; i++)
      DEBUG(100,("%X ", (unsigned char)password[i]));
    DEBUG(100,("|\n"));
    DEBUG(100,("Given challenge was |"));
    for(i = 0; i < 8; i++)
      DEBUG(100,("%X ", (unsigned char)c8[i]));
    DEBUG(100,("|\n"));
    DEBUG(100,("Value from encryption was |"));
    for(i = 0; i < 24; i++)
      DEBUG(100,("%X ", (unsigned char)p24[i]));
    DEBUG(100,("|\n"));
  }
#endif
  return (memcmp(p24, password, 24) == 0);
}

/****************************************************************************
 Do a specific test for an smb password being correct, given a smb_password and
 the lanman and NT responses.
****************************************************************************/
BOOL smb_password_ok(SAM_ACCOUNT *sampass, uchar chal[8],
                     uchar lm_pass[24], uchar nt_pass[24])
{
        uchar challenge[8];
        char* user_name;
        uint8 *nt_pw, *lm_pw;

        if (!lm_pass || !sampass) 
                return(False);

        user_name = pdb_get_username(sampass);
        
        DEBUG(4,("smb_password_ok: Checking SMB password for user %s\n",user_name));

        if(pdb_get_acct_ctrl(sampass) & ACB_DISABLED) {
                DEBUG(1,("smb_password_ok: account for user %s was disabled.\n", user_name));
                return(False);
        }

        if (chal == NULL) {
                DEBUG(5,("smb_password_ok: use last SMBnegprot challenge\n"));
                if (!last_challenge(challenge)) {
                        DEBUG(1,("smb_password_ok: no challenge done - password failed\n"));
                        return False;
                }
        } else {
                DEBUG(5,("smb_password_ok: challenge received\n"));
                memcpy(challenge, chal, 8);
        }

        nt_pw = pdb_get_nt_passwd(sampass);
        
        if ((Protocol >= PROTOCOL_NT1) && (nt_pw != NULL)) {
                /* We have the NT MD4 hash challenge available - see if we can
                   use it (ie. does it exist in the smbpasswd file).
                */
                DEBUG(4,("smb_password_ok: Checking NT MD4 password\n"));
                if (smb_password_check((char *)nt_pass, (uchar *)nt_pw, challenge)) {
                        DEBUG(4,("smb_password_ok: NT MD4 password check succeeded\n"));
                        return(True);
                }
                DEBUG(4,("smb_password_ok: NT MD4 password check failed\n"));
        }

        /* Try against the lanman password. pdb_get_lanman_passwd(sampass) == NULL 
           means no password, allow access. */

        lm_pw = pdb_get_lanman_passwd(sampass);
        
        if((lm_pw == NULL) && (pdb_get_acct_ctrl(sampass) & ACB_PWNOTREQ)) 
        {
                DEBUG(4,("smb_password_ok: no password required for user %s\n",user_name));
                return True;
        }

        if(lp_lanman_auth() && (lm_pw != NULL)) {
                DEBUG(4,("smb_password_ok: Checking LM password\n"));
                if(smb_password_check((char *)lm_pass,(uchar *)lm_pw, challenge)) {
                        DEBUG(4,("smb_password_ok: LM password check succeeded\n"));
                        return(True);
                }
                DEBUG(4,("smb_password_ok: LM password check failed\n"));
        }

        return False;
}


/****************************************************************************
check if a username/password is OK assuming the password is a 24 byte
SMB hash
return True if the password is correct, False otherwise
****************************************************************************/

BOOL pass_check_smb(char *user, char *domain, uchar *chal, 
                    uchar *lm_pwd, uchar *nt_pwd, struct passwd *pwd)
{
        struct passwd *pass;
        SAM_ACCOUNT *sampass=NULL;
        BOOL ret;

        if (!lm_pwd || !nt_pwd)
        {
                return(False);
        }

        /* FIXME! this code looks to be unnecessary now that the passdb
           validates that the username exists and has a valid uid */
        if (pwd != NULL && user == NULL)
        {
                pass = (struct passwd *) pwd;
                user = pass->pw_name;
        }
        else
        {
                /* I don't get this call here.  I think it should be moved.
                   Need to check on it.     --jerry */
                pass = smb_getpwnam(user,True);
        }

        if (pass == NULL)
        {
                DEBUG(1,("Couldn't find user '%s' in UNIX password database.\n",user));
                return(False);
        }

        pdb_init_sam(&sampass);

        /* get the account information */
        ret = pdb_getsampwnam(sampass, user);
        if (ret == False)
        {
                DEBUG(1,("Couldn't find user '%s' in passdb file.\n", user));
                pdb_free_sam(sampass);
                return(False);
        }

        /* Quit if the account was disabled. */
        if(pdb_get_acct_ctrl(sampass) & ACB_DISABLED) {
                DEBUG(1,("Account for user '%s' was disabled.\n", user));
                pdb_free_sam(sampass);
                return(False);
        }

        /* Ensure the uid's match 
           FIXME!  This also seems unnecessary --jerry */
#if 0   /* GWC */
        if (smb_pass->smb_userid != pass->pw_uid)
        {
                DEBUG(0,("Error : UNIX and SMB uids in password files do not match for user '%s'!\n", user));
                pdb_free_sam(sampass);
                return(False);
        }
#endif

        if (pdb_get_acct_ctrl(sampass) & ACB_PWNOTREQ) 
        {
                if (lp_null_passwords()) 
                {
                        DEBUG(3,("Account for user '%s' has no password and null passwords are allowed.\n", user));
                        pdb_free_sam(sampass);
                        return(True);
                } 
                else 
                {
                        DEBUG(3,("Account for user '%s' has no password and null passwords are NOT allowed.\n", user));
                        pdb_free_sam(sampass);
                        return(False);
                }               
        }

        if (smb_password_ok(sampass, chal, lm_pwd, nt_pwd))
        {
                pdb_free_sam(sampass);
                return(True);
        }
        
        DEBUG(2,("pass_check_smb failed - invalid password for user [%s]\n", user));
        pdb_free_sam(sampass);
        return False;
}

/****************************************************************************
check if a username/password pair is OK either via the system password
database or the encrypted SMB password database
return True if the password is correct, False otherwise
****************************************************************************/
BOOL password_ok(char *user, char *password, int pwlen, struct passwd *pwd)
{
        BOOL ret;

        if ((pwlen == 0) && !lp_null_passwords()) {
                DEBUG(4,("Null passwords not allowed.\n"));
                return False;
        }

        if (pwlen == 24 || (lp_encrypted_passwords() && (pwlen == 0) && lp_null_passwords())) {
                /* if 24 bytes long assume it is an encrypted password */
                uchar challenge[8];

                if (!last_challenge(challenge)) {
                        DEBUG(0,("Error: challenge not done for user=%s\n", user));
                        return False;
                }

                ret = pass_check_smb(user, global_myworkgroup,
                                      challenge, (uchar *)password, (uchar *)password, pwd);

                /*
                 * Try with PAM (may not be compiled in - returns True if not. JRA).
                 * FIXME ! Should this be called if we're using winbindd ? What about
                 * non-local accounts ? JRA.
                 */

                if (ret)
                        return (smb_pam_accountcheck(user) == NT_STATUS_NOPROBLEMO);
        } 

        return pass_check(user, password, pwlen, pwd, 
                          lp_update_encrypted() ? 
                          update_smbpassword_file : NULL);
}

/****************************************************************************
check if a username is valid
****************************************************************************/
BOOL user_ok(char *user,int snum)
{
        pstring valid, invalid;
        BOOL ret;

        StrnCpy(valid, lp_valid_users(snum), sizeof(pstring)-1);
        StrnCpy(invalid, lp_invalid_users(snum), sizeof(pstring)-1);

        pstring_sub(valid,"%S",lp_servicename(snum));
        pstring_sub(invalid,"%S",lp_servicename(snum));
        
        ret = !user_in_list(user,invalid);
        
        if (ret && valid && *valid) {
                ret = user_in_list(user,valid);
        }

        if (ret && lp_onlyuser(snum)) {
                char *user_list = lp_username(snum);
                pstring_sub(user_list,"%S",lp_servicename(snum));
                ret = user_in_list(user,user_list);
        }

        return(ret);
}




/****************************************************************************
validate a group username entry. Return the username or NULL
****************************************************************************/
static char *validate_group(char *group,char *password,int pwlen,int snum)
{
#ifdef HAVE_NETGROUP
        {
                char *host, *user, *domain;
                setnetgrent(group);
                while (getnetgrent(&host, &user, &domain)) {
                        if (user) {
                                if (user_ok(user, snum) && 
                                    password_ok(user,password,pwlen,NULL)) {
                                        endnetgrent();
                                        return(user);
                                }
                        }
                }
                endnetgrent();
        }
#endif
  
#ifdef HAVE_GETGRENT
        {
                struct group *gptr;
                setgrent();
                while ((gptr = (struct group *)getgrent())) {
                        if (strequal(gptr->gr_name,group))
                                break;
                }

                /*
                 * As user_ok can recurse doing a getgrent(), we must
                 * copy the member list into a pstring on the stack before
                 * use. Bug pointed out by leon@eatworms.swmed.edu.
                 */

                if (gptr) {
                        pstring member_list;
                        char *member;
                        size_t copied_len = 0;
                        int i;

                        *member_list = '\0';
                        member = member_list;

                        for(i = 0; gptr->gr_mem && gptr->gr_mem[i]; i++) {
                                size_t member_len = strlen(gptr->gr_mem[i]) + 1;
                                if( copied_len + member_len < sizeof(pstring)) { 

                                        DEBUG(10,("validate_group: = gr_mem = %s\n", gptr->gr_mem[i]));

                                        safe_strcpy(member, gptr->gr_mem[i], sizeof(pstring) - copied_len - 1);
                                        copied_len += member_len;
                                        member += copied_len;
                                } else {
                                        *member = '\0';
                                }
                        }

                        endgrent();

                        member = member_list;
                        while (*member) {
                                static fstring name;
                                fstrcpy(name,member);
                                if (user_ok(name,snum) &&
                                    password_ok(name,password,pwlen,NULL)) {
                                        endgrent();
                                        return(&name[0]);
                                }

                                DEBUG(10,("validate_group = member = %s\n", member));

                                member += strlen(member) + 1;
                        }
                } else {
                        endgrent();
                        return NULL;
                }
        }
#endif
        return(NULL);
}



/****************************************************************************
check for authority to login to a service with a given username/password
****************************************************************************/
BOOL authorise_login(int snum,char *user,char *password, int pwlen, 
                     BOOL *guest,BOOL *force,uint16 vuid)
{
  BOOL ok = False;
  user_struct *vuser = get_valid_user_struct(vuid);

  if (lp_security() > SEC_SHARE && !vuser) {
          DEBUG(1,("authorise_login: refusing user %s with no session setup\n",
                   user));
          return False;
  }
  
  *guest = False;
  
#if DEBUG_PASSWORD
  DEBUG(100,("checking authorisation on user=%s pass=%s\n",user,password));
#endif

  /* there are several possibilities:
     1) login as the given user with given password
     2) login as a previously registered username with the given password
     3) login as a session list username with the given password
     4) login as a previously validated user/password pair
     5) login as the "user =" user with given password
     6) login as the "user =" user with no password (guest connection)
     7) login as guest user with no password

     if the service is guest_only then steps 1 to 5 are skipped
  */

  if (GUEST_ONLY(snum)) *force = True;

  if (!(GUEST_ONLY(snum) && GUEST_OK(snum)))
    {
      /* check the given username and password */
      if (!ok && (*user) && user_ok(user,snum)) {
        ok = password_ok(user,password, pwlen, NULL);
        if (ok) DEBUG(3,("ACCEPTED: given username password ok\n"));
      }

      /* check for a previously registered guest username */
      if (!ok && (vuser != 0) && vuser->guest) {          
        if (user_ok(vuser->user.unix_name,snum) &&
            password_ok(vuser->user.unix_name, password, pwlen, NULL)) {
          fstrcpy(user, vuser->user.unix_name);
          vuser->guest = False;
          DEBUG(3,("ACCEPTED: given password with registered user %s\n", user));
          ok = True;
        }
      }


      /* now check the list of session users */
    if (!ok)
    {
      char *auser;
      char *user_list = strdup(session_users);
      if (!user_list) return(False);

      for (auser=strtok(user_list,LIST_SEP); 
           !ok && auser; 
           auser = strtok(NULL,LIST_SEP))
      {
        fstring user2;
        fstrcpy(user2,auser);
        if (!user_ok(user2,snum)) continue;
                  
        if (password_ok(user2,password, pwlen, NULL)) {
          ok = True;
          fstrcpy(user,user2);
          DEBUG(3,("ACCEPTED: session list username and given password ok\n"));
        }
      }
      free(user_list);
    }

    /* check for a previously validated username/password pair */
    if (!ok && (lp_security() > SEC_SHARE) &&
        (vuser != 0) && !vuser->guest &&
        user_ok(vuser->user.unix_name,snum)) {
      fstrcpy(user,vuser->user.unix_name);
      *guest = False;
      DEBUG(3,("ACCEPTED: validated uid ok as non-guest\n"));
      ok = True;
    }

      /* check for a rhosts entry */
      if (!ok && user_ok(user,snum) && check_hosts_equiv(user)) {
        ok = True;
        DEBUG(3,("ACCEPTED: hosts equiv or rhosts entry\n"));
      }

      /* check the user= fields and the given password */
      if (!ok && lp_username(snum)) {
        char *auser;
        pstring user_list;
        StrnCpy(user_list,lp_username(snum),sizeof(pstring));

        pstring_sub(user_list,"%S",lp_servicename(snum));
          
        for (auser=strtok(user_list,LIST_SEP);
             auser && !ok;
             auser = strtok(NULL,LIST_SEP))
          {
            if (*auser == '@')
              {
                auser = validate_group(auser+1,password,pwlen,snum);
                if (auser)
                  {
                    ok = True;
                    fstrcpy(user,auser);
                    DEBUG(3,("ACCEPTED: group username and given password ok\n"));
                  }
              }
            else
              {
                fstring user2;
                fstrcpy(user2,auser);
                if (user_ok(user2,snum) && 
                    password_ok(user2,password,pwlen,NULL))
                  {
                    ok = True;
                    fstrcpy(user,user2);
                    DEBUG(3,("ACCEPTED: user list username and given password ok\n"));
                  }
              }
          }
      }      
    } /* not guest only */

  /* check for a normal guest connection */
  if (!ok && GUEST_OK(snum))
    {
      fstring guestname;
      StrnCpy(guestname,lp_guestaccount(snum),sizeof(guestname)-1);
      if (Get_Pwnam(guestname,True))
        {
          fstrcpy(user,guestname);
          ok = True;
          DEBUG(3,("ACCEPTED: guest account and guest ok\n"));
        }
      else
        DEBUG(0,("Invalid guest account %s??\n",guestname));
      *guest = True;
    }

  if (ok && !user_ok(user,snum))
    {
      DEBUG(0,("rejected invalid user %s\n",user));
      ok = False;
    }

  return(ok);
}


/****************************************************************************
read the a hosts.equiv or .rhosts file and check if it
allows this user from this machine
****************************************************************************/
static BOOL check_user_equiv(char *user, char *remote, char *equiv_file)
{
  int plus_allowed = 1;
  char *file_host;
  char *file_user;
  char **lines = file_lines_load(equiv_file, NULL, False);
  int i;

  DEBUG(5, ("check_user_equiv %s %s %s\n", user, remote, equiv_file));
  if (! lines) return False;
  for (i=0; lines[i]; i++) {
    char *buf = lines[i];
    trim_string(buf," "," ");

    if (buf[0] != '#' && buf[0] != '\n') 
    {
      BOOL is_group = False;
      int plus = 1;
      char *bp = buf;
      if (strcmp(buf, "NO_PLUS\n") == 0)
      {
        DEBUG(6, ("check_user_equiv NO_PLUS\n"));
        plus_allowed = 0;
      }
      else {
        if (buf[0] == '+') 
        {
          bp++;
          if (*bp == '\n' && plus_allowed) 
          {
            /* a bare plus means everbody allowed */
            DEBUG(6, ("check_user_equiv everybody allowed\n"));
            file_lines_free(lines);
            return True;
          }
        }
        else if (buf[0] == '-')
        {
          bp++;
          plus = 0;
        }
        if (*bp == '@') 
        {
          is_group = True;
          bp++;
        }
        file_host = strtok(bp, " \t\n");
        file_user = strtok(NULL, " \t\n");
        DEBUG(7, ("check_user_equiv %s %s\n", file_host ? file_host : "(null)", 
                 file_user ? file_user : "(null)" ));
        if (file_host && *file_host) 
        {
          BOOL host_ok = False;

#if defined(HAVE_NETGROUP) && defined(HAVE_YP_GET_DEFAULT_DOMAIN)
          if (is_group)
            {
              static char *mydomain = NULL;
              if (!mydomain)
                yp_get_default_domain(&mydomain);
              if (mydomain && innetgr(file_host,remote,user,mydomain))
                host_ok = True;
            }
#else
          if (is_group)
            {
              DEBUG(1,("Netgroups not configured\n"));
              continue;
            }
#endif

          /* is it this host */
          /* the fact that remote has come from a call of gethostbyaddr
           * means that it may have the fully qualified domain name
           * so we could look up the file version to get it into
           * a canonical form, but I would rather just type it
           * in full in the equiv file
           */
          if (!host_ok && !is_group && strequal(remote, file_host))
            host_ok = True;

          if (!host_ok)
            continue;

          /* is it this user */
          if (file_user == 0 || strequal(user, file_user)) 
            {
              DEBUG(5, ("check_user_equiv matched %s%s %s\n",
                        (plus ? "+" : "-"), file_host,
                        (file_user ? file_user : "")));
              file_lines_free(lines);
              return (plus ? True : False);
            }
        }
      }
    }
  }
  file_lines_free(lines);
  return False;
}


/****************************************************************************
check for a possible hosts equiv or rhosts entry for the user
****************************************************************************/
BOOL check_hosts_equiv(char *user)
{
  char *fname = NULL;
  pstring rhostsfile;
  struct passwd *pass = Get_Pwnam(user,True);

  if (!pass) 
    return(False);

  fname = lp_hosts_equiv();

  /* note: don't allow hosts.equiv on root */
  if (fname && *fname && (pass->pw_uid != 0)) {
          if (check_user_equiv(user,client_name(),fname))
                  return(True);
  }
  
  if (lp_use_rhosts())
    {
      char *home = get_user_home_dir(user);
      if (home) {
              slprintf(rhostsfile, sizeof(rhostsfile)-1, "%s/.rhosts", home);
              if (check_user_equiv(user,client_name(),rhostsfile))
                      return(True);
      }
    }

  return(False);
}


/****************************************************************************
 Return the client state structure.
****************************************************************************/

struct cli_state *server_client(void)
{
        static struct cli_state pw_cli;
        return &pw_cli;
}

/****************************************************************************
 Support for server level security.
****************************************************************************/

struct cli_state *server_cryptkey(void)
{
        struct cli_state *cli;
        fstring desthost;
        struct in_addr dest_ip;
        char *p, *pserver;
        BOOL connected_ok = False;

        cli = server_client();

        if (!cli_initialise(cli))
                return NULL;

        pserver = strdup(lp_passwordserver());
        p = pserver;

        while(next_token( &p, desthost, LIST_SEP, sizeof(desthost))) {
                standard_sub_basic(desthost);
                strupper(desthost);

                if(!resolve_name( desthost, &dest_ip, 0x20)) {
                        DEBUG(1,("server_cryptkey: Can't resolve address for %s\n",desthost));
                        continue;
                }

                if (ismyip(dest_ip)) {
                        DEBUG(1,("Password server loop - disabling password server %s\n",desthost));
                        continue;
                }

                if (cli_connect(cli, desthost, &dest_ip)) {
                        DEBUG(3,("connected to password server %s\n",desthost));
                        connected_ok = True;
                        break;
                }
        }

        free(pserver);

        if (!connected_ok) {
                DEBUG(0,("password server not available\n"));
                cli_shutdown(cli);
                return NULL;
        }

        if (!attempt_netbios_session_request(cli, global_myname, desthost, &dest_ip))
                return NULL;

        DEBUG(3,("got session\n"));

        if (!cli_negprot(cli)) {
                DEBUG(1,("%s rejected the negprot\n",desthost));
                cli_shutdown(cli);
                return NULL;
        }

        if (cli->protocol < PROTOCOL_LANMAN2 ||
            !(cli->sec_mode & 1)) {
                DEBUG(1,("%s isn't in user level security mode\n",desthost));
                cli_shutdown(cli);
                return NULL;
        }

        DEBUG(3,("password server OK\n"));

        return cli;
}

/****************************************************************************
 Validate a password with the password server.
****************************************************************************/

BOOL server_validate(char *user, char *domain, 
                     char *pass, int passlen,
                     char *ntpass, int ntpasslen)
{
        struct cli_state *cli;
        static unsigned char badpass[24];
        static fstring baduser; 
        static BOOL tested_password_server = False;
        static BOOL bad_password_server = False;

        cli = server_client();

        if (!cli->initialised) {
                DEBUG(1,("password server %s is not connected\n", cli->desthost));
                return(False);
        }  

        if(badpass[0] == 0)
                memset(badpass, 0x1f, sizeof(badpass));

        if((passlen == sizeof(badpass)) && !memcmp(badpass, pass, passlen)) {
                /* 
                 * Very unlikely, our random bad password is the same as the users
                 * password.
                 */
                memset(badpass, badpass[0]+1, sizeof(badpass));
        }

        if(baduser[0] == 0) {
                fstrcpy(baduser, INVALID_USER_PREFIX);
                fstrcat(baduser, global_myname);
        }

        /*
         * Attempt a session setup with a totally incorrect password.
         * If this succeeds with the guest bit *NOT* set then the password
         * server is broken and is not correctly setting the guest bit. We
         * need to detect this as some versions of NT4.x are broken. JRA.
         */

        if(!tested_password_server) {
                if (cli_session_setup(cli, baduser, (char *)badpass, sizeof(badpass), 
                                        (char *)badpass, sizeof(badpass), domain)) {

                        /*
                         * We connected to the password server so we
                         * can say we've tested it.
                         */
                        tested_password_server = True;

                        if ((SVAL(cli->inbuf,smb_vwv2) & 1) == 0) {
                                DEBUG(0,("server_validate: password server %s allows users as non-guest \
with a bad password.\n", cli->desthost));
                                DEBUG(0,("server_validate: This is broken (and insecure) behaviour. Please do not \
use this machine as the password server.\n"));
                                cli_ulogoff(cli);

                                /*
                                 * Password server has the bug.
                                 */
                                bad_password_server = True;
                                return False;
                        }
                        cli_ulogoff(cli);
                }
        } else {

                /*
                 * We have already tested the password server.
                 * Fail immediately if it has the bug.
                 */

                if(bad_password_server) {
                        DEBUG(0,("server_validate: [1] password server %s allows users as non-guest \
with a bad password.\n", cli->desthost));
                        DEBUG(0,("server_validate: [1] This is broken (and insecure) behaviour. Please do not \
use this machine as the password server.\n"));
                        return False;
                }
        }

        /*
         * Now we know the password server will correctly set the guest bit, or is
         * not guest enabled, we can try with the real password.
         */

        if (!cli_session_setup(cli, user, pass, passlen, ntpass, ntpasslen, domain)) {
                DEBUG(1,("password server %s rejected the password\n", cli->desthost));
                return False;
        }

        /* if logged in as guest then reject */
        if ((SVAL(cli->inbuf,smb_vwv2) & 1) != 0) {
                DEBUG(1,("password server %s gave us guest only\n", cli->desthost));
                cli_ulogoff(cli);
                return(False);
        }

        cli_ulogoff(cli);

        return(True);
}

/***********************************************************************
 Connect to a remote machine for domain security authentication
 given a name or IP address.
************************************************************************/

static BOOL connect_to_domain_password_server(struct cli_state *pcli, 
                                              char *server,
                                              unsigned char *trust_passwd)
{
  struct in_addr dest_ip;
  fstring remote_machine;

  if(cli_initialise(pcli) == False) {
    DEBUG(0,("connect_to_domain_password_server: unable to initialize client connection.\n"));
    return False;
  }

  if (is_ipaddress(server)) {
          struct in_addr to_ip;
          
          /* we shouldn't have 255.255.255.255 forthe IP address of 
             a password server anyways */
          if ((to_ip.s_addr=inet_addr(server)) == 0xFFFFFFFF) {
                DEBUG (0,("connect_to_domain_password_server: inet_addr(%s) returned 0xFFFFFFFF!\n", server));
                return False;
          }

          if (!name_status_find(0x20, to_ip, remote_machine)) {
                  DEBUG(0, ("connect_to_domain_password_server: Can't "
                            "resolve name for IP %s\n", server));
                  return False;
          }
  } else {
          fstrcpy(remote_machine, server);
  }

  standard_sub_basic(remote_machine);
  strupper(remote_machine);

  if(!resolve_name( remote_machine, &dest_ip, 0x20)) {
    DEBUG(1,("connect_to_domain_password_server: Can't resolve address for %s\n", remote_machine));
    cli_shutdown(pcli);
    return False;
  }
  
  if (ismyip(dest_ip)) {
    DEBUG(1,("connect_to_domain_password_server: Password server loop - not using password server %s\n",
         remote_machine));
    cli_shutdown(pcli);
    return False;
  }
  
  if (!cli_connect(pcli, remote_machine, &dest_ip)) {
    DEBUG(0,("connect_to_domain_password_server: unable to connect to SMB server on \
machine %s. Error was : %s.\n", remote_machine, cli_errstr(pcli) ));
    cli_shutdown(pcli);
    return False;
  }
  
  if (!attempt_netbios_session_request(pcli, global_myname, remote_machine, &dest_ip)) {
    DEBUG(0,("connect_to_password_server: machine %s rejected the NetBIOS \
session request. Error was : %s.\n", remote_machine, cli_errstr(pcli) ));
    return False;
  }
  
  pcli->protocol = PROTOCOL_NT1;

  if (!cli_negprot(pcli)) {
    DEBUG(0,("connect_to_domain_password_server: machine %s rejected the negotiate protocol. \
Error was : %s.\n", remote_machine, cli_errstr(pcli) ));
    cli_shutdown(pcli);
    return False;
  }

  if (pcli->protocol != PROTOCOL_NT1) {
    DEBUG(0,("connect_to_domain_password_server: machine %s didn't negotiate NT protocol.\n",
                   remote_machine));
    cli_shutdown(pcli);
    return False;
  }

  /*
   * Do an anonymous session setup.
   */

  if (!cli_session_setup(pcli, "", "", 0, "", 0, "")) {
    DEBUG(0,("connect_to_domain_password_server: machine %s rejected the session setup. \
Error was : %s.\n", remote_machine, cli_errstr(pcli) ));
    cli_shutdown(pcli);
    return False;
  }

  if (!(pcli->sec_mode & 1)) {
    DEBUG(1,("connect_to_domain_password_server: machine %s isn't in user level security mode\n",
               remote_machine));
    cli_shutdown(pcli);
    return False;
  }

  if (!cli_send_tconX(pcli, "IPC$", "IPC", "", 1)) {
    DEBUG(0,("connect_to_domain_password_server: machine %s rejected the tconX on the IPC$ share. \
Error was : %s.\n", remote_machine, cli_errstr(pcli) ));
    cli_shutdown(pcli);
    return False;
  }

  /*
   * We now have an anonymous connection to IPC$ on the domain password server.
   */

  /*
   * Even if the connect succeeds we need to setup the netlogon
   * pipe here. We do this as we may just have changed the domain
   * account password on the PDC and yet we may be talking to
   * a BDC that doesn't have this replicated yet. In this case
   * a successful connect to a DC needs to take the netlogon connect
   * into account also. This patch from "Bjart Kvarme" <bjart.kvarme@usit.uio.no>.
   */

  if(cli_nt_session_open(pcli, PIPE_NETLOGON) == False) {
    DEBUG(0,("connect_to_domain_password_server: unable to open the domain client session to \
machine %s. Error was : %s.\n", remote_machine, cli_errstr(pcli)));
    cli_nt_session_close(pcli);
    cli_ulogoff(pcli);
    cli_shutdown(pcli);
    return False;
  }

  if (cli_nt_setup_creds(pcli, trust_passwd) == False) {
    DEBUG(0,("connect_to_domain_password_server: unable to setup the PDC credentials to machine \
%s. Error was : %s.\n", remote_machine, cli_errstr(pcli)));
    cli_nt_session_close(pcli);
    cli_ulogoff(pcli);
    cli_shutdown(pcli);
    return(False);
  }

  return True;
}

/***********************************************************************
 Utility function to attempt a connection to an IP address of a DC.
************************************************************************/

static BOOL attempt_connect_to_dc(struct cli_state *pcli, struct in_addr *ip, unsigned char *trust_passwd)
{
  fstring dc_name;

  /*
   * Ignore addresses we have already tried.
   */

  if (ip_equal(ipzero, *ip))
          return False;

  if (!lookup_pdc_name(global_myname, lp_workgroup(), ip, dc_name))
          return False;

  return connect_to_domain_password_server(pcli, dc_name, trust_passwd);
}



/***********************************************************************
 We have been asked to dynamcially determine the IP addresses of
 the PDC and BDC's for this DOMAIN, and query them in turn.
************************************************************************/
static BOOL find_connect_pdc(struct cli_state *pcli, unsigned char *trust_passwd, time_t last_change_time)
{
        struct in_addr *ip_list = NULL;
        int count = 0;
        int i;
        BOOL connected_ok = False;
        time_t time_now = time(NULL);
        BOOL use_pdc_only = False;

        /*
         * If the time the machine password has changed
         * was less than an hour ago then we need to contact
         * the PDC only, as we cannot be sure domain replication
         * has yet taken place. Bug found by Gerald (way to go
         * Gerald !). JRA.
         */

        if (time_now - last_change_time < 3600)
                use_pdc_only = True;

        if (!get_dc_list(use_pdc_only, lp_workgroup(), &ip_list, &count))
                return False;

        /*
         * Firstly try and contact a PDC/BDC who has the same
         * network address as any of our interfaces.
         */
        for(i = 0; i < count; i++) {
                if(!is_local_net(ip_list[i]))
                        continue;

                if((connected_ok = attempt_connect_to_dc(pcli, &ip_list[i], trust_passwd))) 
                        break;
                
                ip_list[i] = ipzero; /* Tried and failed. */
        }

        /*
         * Secondly try and contact a random PDC/BDC.
         */
        if(!connected_ok) {
                i = (sys_random() % count);

                if (!(connected_ok = attempt_connect_to_dc(pcli, &ip_list[i], trust_passwd)))
                        ip_list[i] = ipzero; /* Tried and failed. */
        }

        /*
         * Finally go through the IP list in turn, ignoring any addresses
         * we have already tried.
         */
        if(!connected_ok) {
                /*
                 * Try and connect to any of the other IP addresses in the PDC/BDC list.
                 * Note that from a WINS server the #1 IP address is the PDC.
                 */
                for(i = 0; i < count; i++) {
                        if((connected_ok = attempt_connect_to_dc(pcli, &ip_list[i], trust_passwd)))
                                break;
                }
        }

        if(ip_list != NULL)
                free((char *)ip_list);


        return connected_ok;
}



/***********************************************************************
 Do the same as security=server, but using NT Domain calls and a session
 key from the machine password.
************************************************************************/

BOOL domain_client_validate( char *user, char *domain, 
                             char *smb_apasswd, int smb_apasslen, 
                             char *smb_ntpasswd, int smb_ntpasslen,
                             BOOL *user_exists)
{
  unsigned char local_challenge[8];
  unsigned char local_lm_response[24];
  unsigned char local_nt_response[24];
  unsigned char trust_passwd[16];
  fstring remote_machine;
  char *p, *pserver;
  NET_ID_INFO_CTR ctr;
  NET_USER_INFO_3 info3;
  struct cli_state cli;
  uint32 smb_uid_low;
  BOOL connected_ok = False;
  time_t last_change_time;

  if(user_exists != NULL)
    *user_exists = True; /* Only set false on a very specific error. */
 
  /* 
   * Check that the requested domain is not our own machine name.
   * If it is, we should never check the PDC here, we use our own local
   * password file.
   */

  if(strequal( domain, global_myname)) {
    DEBUG(3,("domain_client_validate: Requested domain was for this machine.\n"));
    return False;
  }

  /*
   * Next, check that the passwords given were encrypted.
   */

  if(((smb_apasslen != 24) && (smb_apasslen != 0)) || 
     ((smb_ntpasslen != 24) && (smb_ntpasslen != 0))) {

    /*
     * Not encrypted - do so.
     */

    DEBUG(3,("domain_client_validate: User passwords not in encrypted format.\n"));
    generate_random_buffer( local_challenge, 8, False);
    SMBencrypt( (uchar *)smb_apasswd, local_challenge, local_lm_response);
    SMBNTencrypt((uchar *)smb_ntpasswd, local_challenge, local_nt_response);
    smb_apasslen = 24;
    smb_ntpasslen = 24;
    smb_apasswd = (char *)local_lm_response;
    smb_ntpasswd = (char *)local_nt_response;
  } else {

    /*
     * Encrypted - get the challenge we sent for these
     * responses.
     */

    if (!last_challenge(local_challenge)) {
      DEBUG(0,("domain_client_validate: no challenge done - password failed\n"));
      return False;
    }
  }

  /*
   * Get the machine account password for our primary domain
   */
  if (!secrets_fetch_trust_account_password(lp_workgroup(), trust_passwd, &last_change_time))
  {
          DEBUG(0, ("domain_client_validate: could not fetch trust account password for domain %s\n", lp_workgroup()));
          return False;
  }

  /*
   * At this point, smb_apasswd points to the lanman response to
   * the challenge in local_challenge, and smb_ntpasswd points to
   * the NT response to the challenge in local_challenge. Ship
   * these over the secure channel to a domain controller and
   * see if they were valid.
   */

  ZERO_STRUCT(cli);

  /*
   * Treat each name in the 'password server =' line as a potential
   * PDC/BDC. Contact each in turn and try and authenticate.
   */

  pserver = lp_passwordserver();
  if (! *pserver) pserver = "*";
  p = pserver;

  while (!connected_ok &&
         next_token(&p,remote_machine,LIST_SEP,sizeof(remote_machine))) {
          if(strequal(remote_machine, "*")) {
                  connected_ok = find_connect_pdc(&cli, trust_passwd, last_change_time);
          } else {
                  connected_ok = connect_to_domain_password_server(&cli, remote_machine, trust_passwd);
          }
  }

  if (!connected_ok) {
    DEBUG(0,("domain_client_validate: Domain password server not available.\n"));
    cli_shutdown(&cli);
    return False;
  }

  /* We really don't care what LUID we give the user. */
  generate_random_buffer( (unsigned char *)&smb_uid_low, 4, False);

  ZERO_STRUCT(info3);

  if(cli_nt_login_network(&cli, domain, user, smb_uid_low, (char *)local_challenge,
                          ((smb_apasslen != 0) ? smb_apasswd : NULL),
                          ((smb_ntpasslen != 0) ? smb_ntpasswd : NULL),
                          &ctr, &info3) == False) {
    uint32 nt_rpc_err;

    cli_error(&cli, NULL, NULL, &nt_rpc_err);
    DEBUG(0,("domain_client_validate: unable to validate password for user %s in domain \
%s to Domain controller %s. Error was %s.\n", user, domain, remote_machine, cli_errstr(&cli)));
    cli_nt_session_close(&cli);
    cli_ulogoff(&cli);
    cli_shutdown(&cli);

    if((nt_rpc_err == NT_STATUS_NO_SUCH_USER) && (user_exists != NULL))
      *user_exists = False;

    return False;
  }

  /*
   * Here, if we really want it, we have lots of info about the user in info3.
   */

#if 0
  /* 
   * We don't actually need to do this - plus it fails currently with
   * NT_STATUS_INVALID_INFO_CLASS - we need to know *exactly* what to
   * send here. JRA.
   */

  if(cli_nt_logoff(&cli, &ctr) == False) {
    DEBUG(0,("domain_client_validate: unable to log off user %s in domain \
%s to Domain controller %s. Error was %s.\n", user, domain, remote_machine, cli_errstr(&cli)));        
    cli_nt_session_close(&cli);
    cli_ulogoff(&cli);
    cli_shutdown(&cli);
    return False;
  }
#endif /* 0 */

  /* Note - once the cli stream is shutdown the mem_ctx used
   to allocate the other_sids and gids structures has been deleted - so
   these pointers are no longer valid..... */

  cli_nt_session_close(&cli);
  cli_ulogoff(&cli);
  cli_shutdown(&cli);
  return True;
}