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[Samba.git] / source / nsswitch / winbindd_util.c

/* 
   Unix SMB/CIFS implementation.

   Winbind daemon for ntdom nss module

   Copyright (C) Tim Potter 2000-2001
   Copyright (C) 2001 by Martin Pool <mbp@samba.org>
   
   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 "winbindd.h"

#undef DBGC_CLASS
#define DBGC_CLASS DBGC_WINBIND

/**
 * @file winbindd_util.c
 *
 * Winbind daemon for NT domain authentication nss module.
 **/


/**
 * Used to clobber name fields that have an undefined value.
 *
 * Correct code should never look at a field that has this value.
 **/

static const fstring name_deadbeef = "<deadbeef>";

/* The list of trusted domains.  Note that the list can be deleted and
   recreated using the init_domain_list() function so pointers to
   individual winbindd_domain structures cannot be made.  Keep a copy of
   the domain name instead. */

static struct winbindd_domain *_domain_list;

struct winbindd_domain *domain_list(void)
{
        /* Initialise list */

        if (!_domain_list) 
                if (!init_domain_list()) 
                        return NULL;

        return _domain_list;
}

/* Free all entries in the trusted domain list */

void free_domain_list(void)
{
        struct winbindd_domain *domain = _domain_list;

        while(domain) {
                struct winbindd_domain *next = domain->next;
                
                DLIST_REMOVE(_domain_list, domain);
                SAFE_FREE(domain);
                domain = next;
        }
}


/* Add a trusted domain to our list of domains */
static struct winbindd_domain *add_trusted_domain(const char *domain_name, const char *alt_name,
                                                  struct winbindd_methods *methods,
                                                  DOM_SID *sid)
{
        struct winbindd_domain *domain;
        const char *alternative_name = NULL;
        
        /* ignore alt_name if we are not in an AD domain */
        
        if ( (lp_security() == SEC_ADS) && alt_name && *alt_name) {
                alternative_name = alt_name;
        }
        
        /* We can't call domain_list() as this function is called from
           init_domain_list() and we'll get stuck in a loop. */
        for (domain = _domain_list; domain; domain = domain->next) {
                if (strequal(domain_name, domain->name) ||
                    strequal(domain_name, domain->alt_name)) {
                        return domain;
                }
                if (alternative_name && *alternative_name) {
                        if (strequal(alternative_name, domain->name) ||
                            strequal(alternative_name, domain->alt_name)) {
                                return domain;
                        }
                }
        }
        
        /* Create new domain entry */

        if ((domain = (struct winbindd_domain *)
             malloc(sizeof(*domain))) == NULL)
                return NULL;

        /* Fill in fields */
        
        ZERO_STRUCTP(domain);

        /* prioritise the short name */
        if (strchr_m(domain_name, '.') && alternative_name && *alternative_name) {
                fstrcpy(domain->name, alternative_name);
                fstrcpy(domain->alt_name, domain_name);
        } else {
                fstrcpy(domain->name, domain_name);
                if (alternative_name) {
                        fstrcpy(domain->alt_name, alternative_name);
                }
        }

        domain->methods = methods;
        domain->backend = NULL;
        domain->sequence_number = DOM_SEQUENCE_NONE;
        domain->last_seq_check = 0;
        if (sid) {
                sid_copy(&domain->sid, sid);
        }
        
        /* see if this is a native mode win2k domain */
           
        domain->native_mode = cm_check_for_native_mode_win2k( domain );
        
        DEBUG(3,("add_trusted_domain: %s is a %s mode domain\n", domain->name,
                domain->native_mode ? "native" : "mixed (or NT4)" ));

        /* Link to domain list */
        DLIST_ADD(_domain_list, domain);
        
        DEBUG(1,("Added domain %s %s %s\n", 
                 domain->name, domain->alt_name,
                 sid?sid_string_static(&domain->sid):""));
        
        return domain;
}

/********************************************************************
 Periodically we need to refresh the trusted domain cache for smbd 
********************************************************************/

void rescan_trusted_domains( void )
{
        static time_t last_scan;
        time_t now = time(NULL);
        struct winbindd_domain *mydomain = NULL;
        
        /* see if the time has come... */
        
        if ( (now > last_scan) && ((now-last_scan) < WINBINDD_RESCAN_FREQ) )
                return;
                
        if ( (mydomain = find_our_domain()) == NULL ) {
                DEBUG(0,("rescan_trusted_domains: Can't find my own domain!\n"));
                return;
        }
        
        /* this will only add new domains we didn't already know about */
        
        add_trusted_domains( mydomain );

        last_scan = now;
        
        return; 
}

/********************************************************************
  rescan our domains looking for new trusted domains
********************************************************************/

void add_trusted_domains( struct winbindd_domain *domain )
{
        TALLOC_CTX *mem_ctx;
        NTSTATUS result;
        time_t t;
        char **names;
        char **alt_names;
        int num_domains = 0;
        DOM_SID *dom_sids, null_sid;
        int i;
        struct winbindd_domain *new_domain;

        /* trusted domains might be disabled */
        if (!lp_allow_trusted_domains()) {
                return;
        }

        DEBUG(5, ("scanning trusted domain list\n"));

        if (!(mem_ctx = talloc_init("init_domain_list")))
                return;
           
        ZERO_STRUCTP(&null_sid);

        t = time(NULL);
        
        /* ask the DC what domains it trusts */
        
        result = domain->methods->trusted_domains(domain, mem_ctx, (unsigned int *)&num_domains,
                &names, &alt_names, &dom_sids);
                
        if ( NT_STATUS_IS_OK(result) ) {

                /* Add each domain to the trusted domain list */
                
                for(i = 0; i < num_domains; i++) {
                        DEBUG(10,("Found domain %s\n", names[i]));
                        add_trusted_domain(names[i], alt_names?alt_names[i]:NULL,
                                domain->methods, &dom_sids[i]);
                                           
                        /* if the SID was empty, we better set it now */
                        
                        if ( sid_equal(&dom_sids[i], &null_sid) ) {
                        
                                new_domain = find_domain_from_name(names[i]);
                                 
                                /* this should never happen */
                                if ( !new_domain ) {    
                                        DEBUG(0,("rescan_trust_domains: can't find the domain I just added! [%s]\n",
                                                names[i]));
                                        break;
                                }
                                 
                                /* call the cache method; which will operate on the winbindd_domain \
                                   passed in and choose either rpc or ads as appropriate */

                                result = domain->methods->domain_sid( new_domain, &new_domain->sid );
                                 
                                if ( NT_STATUS_IS_OK(result) )
                                        sid_copy( &dom_sids[i], &new_domain->sid );
                        }
                        
                        /* store trusted domain in the cache */
                        trustdom_cache_store(names[i], alt_names ? alt_names[i] : NULL,
                                             &dom_sids[i], t + WINBINDD_RESCAN_FREQ);
                }
        }

        talloc_destroy(mem_ctx);
}

/* Look up global info for the winbind daemon */
BOOL init_domain_list(void)
{
        extern struct winbindd_methods cache_methods;
        struct winbindd_domain *domain;

        /* Free existing list */
        free_domain_list();

        /* Add ourselves as the first entry.  It *must* be the first entry */
        
        domain = add_trusted_domain( lp_workgroup(), lp_realm(), &cache_methods, NULL);
        
        domain->primary = True;

        /* get any alternate name for the primary domain */
        
        cache_methods.alternate_name(domain);
        
        /* now we have the correct netbios (short) domain name */
        
        if ( *domain->name )
                set_global_myworkgroup( domain->name );
                
        if (!secrets_fetch_domain_sid(domain->name, &domain->sid)) {
                DEBUG(1, ("Could not fetch sid for our domain %s\n",
                          domain->name));
                return False;
        }

        /* do an initial scan for trusted domains */
        add_trusted_domains(domain);

        return True;
}

/** 
 * Given a domain name, return the struct winbindd domain info for it 
 *
 * @note Do *not* pass lp_workgroup() to this function.  domain_list
 *       may modify it's value, and free that pointer.  Instead, our local
 *       domain may be found by calling find_our_domain().
 *       directly.
 *
 *
 * @return The domain structure for the named domain, if it is working.
 */

struct winbindd_domain *find_domain_from_name(const char *domain_name)
{
        struct winbindd_domain *domain;

        /* Search through list */

        for (domain = domain_list(); domain != NULL; domain = domain->next) {
                if (strequal(domain_name, domain->name) ||
                    (domain->alt_name[0] && strequal(domain_name, domain->alt_name))) {
                        return domain;
                }
        }

        /* Not found */

        return NULL;
}

/* Given a domain sid, return the struct winbindd domain info for it */

struct winbindd_domain *find_domain_from_sid(DOM_SID *sid)
{
        struct winbindd_domain *domain;

        /* Search through list */

        for (domain = domain_list(); domain != NULL; domain = domain->next) {
                if (sid_compare_domain(sid, &domain->sid) == 0)
                        return domain;
        }

        /* Not found */

        return NULL;
}

/* Given a domain sid, return the struct winbindd domain info for it */

struct winbindd_domain *find_our_domain(void)
{
        struct winbindd_domain *domain;

        /* Search through list */

        for (domain = domain_list(); domain != NULL; domain = domain->next) {
                if (domain->primary)
                        return domain;
        }

        /* Not found */

        return NULL;
}

/* Lookup a sid in a domain from a name */

BOOL winbindd_lookup_sid_by_name(struct winbindd_domain *domain, 
                                 const char *name, DOM_SID *sid, 
                                 enum SID_NAME_USE *type)
{
        NTSTATUS result;
        TALLOC_CTX *mem_ctx;

        mem_ctx = talloc_init("lookup_sid_by_name for %s\n", name);
        if (!mem_ctx) 
                return False;
        
        /* Lookup name */
        result = domain->methods->name_to_sid(domain, mem_ctx, name, sid, type);

        talloc_destroy(mem_ctx);
        
        /* Return rid and type if lookup successful */
        if (!NT_STATUS_IS_OK(result)) {
                *type = SID_NAME_UNKNOWN;
        }

        return NT_STATUS_IS_OK(result);
}

/**
 * @brief Lookup a name in a domain from a sid.
 *
 * @param sid Security ID you want to look up.
 * @param name On success, set to the name corresponding to @p sid.
 * @param dom_name On success, set to the 'domain name' corresponding to @p sid.
 * @param type On success, contains the type of name: alias, group or
 * user.
 * @retval True if the name exists, in which case @p name and @p type
 * are set, otherwise False.
 **/
BOOL winbindd_lookup_name_by_sid(DOM_SID *sid,
                                 fstring dom_name,
                                 fstring name,
                                 enum SID_NAME_USE *type)
{
        char *names;
        NTSTATUS result;
        TALLOC_CTX *mem_ctx;
        BOOL rv = False;
        struct winbindd_domain *domain;

        domain = find_domain_from_sid(sid);

        if (!domain) {
                DEBUG(1,("Can't find domain from sid\n"));
                return False;
        }

        /* Lookup name */

        if (!(mem_ctx = talloc_init("winbindd_lookup_name_by_sid")))
                return False;
        
        result = domain->methods->sid_to_name(domain, mem_ctx, sid, &names, type);

        /* Return name and type if successful */
        
        if ((rv = NT_STATUS_IS_OK(result))) {
                fstrcpy(dom_name, domain->name);
                fstrcpy(name, names);
        } else {
                *type = SID_NAME_UNKNOWN;
                fstrcpy(name, name_deadbeef);
        }
        
        talloc_destroy(mem_ctx);

        return rv;
}


/* Free state information held for {set,get,end}{pw,gr}ent() functions */

void free_getent_state(struct getent_state *state)
{
        struct getent_state *temp;

        /* Iterate over state list */

        temp = state;

        while(temp != NULL) {
                struct getent_state *next;

                /* Free sam entries then list entry */

                SAFE_FREE(state->sam_entries);
                DLIST_REMOVE(state, state);
                next = temp->next;

                SAFE_FREE(temp);
                temp = next;
        }
}

/* Parse winbindd related parameters */

BOOL winbindd_param_init(void)
{
        /* Parse winbind uid and winbind_gid parameters */

        if (!lp_idmap_uid(&server_state.uid_low, &server_state.uid_high)) {
                DEBUG(0, ("winbindd: idmap uid range missing or invalid\n"));
                DEBUG(0, ("winbindd: cannot continue, exiting.\n"));
                return False;
        }
        
        if (!lp_idmap_gid(&server_state.gid_low, &server_state.gid_high)) {
                DEBUG(0, ("winbindd: idmap gid range missing or invalid\n"));
                DEBUG(0, ("winbindd: cannot continue, exiting.\n"));
                return False;
        }
        
        return True;
}

/* Check if a domain is present in a comma-separated list of domains */

BOOL check_domain_env(char *domain_env, char *domain)
{
        fstring name;
        const char *tmp = domain_env;

        while(next_token(&tmp, name, ",", sizeof(fstring))) {
                if (strequal(name, domain))
                        return True;
        }

        return False;
}

/* Is this a domain which we may assume no DOMAIN\ prefix? */

static BOOL assume_domain(const char *domain) {
        if ((lp_winbind_use_default_domain()  
                  || lp_winbind_trusted_domains_only()) &&
            strequal(lp_workgroup(), domain)) 
                return True;

        if (strequal(get_global_sam_name(), domain)) 
                return True;
        
        return False;
}

/* Parse a string of the form DOMAIN/user into a domain and a user */

BOOL parse_domain_user(const char *domuser, fstring domain, fstring user)
{
        char *p = strchr(domuser,*lp_winbind_separator());

        if ( !p ) {
                fstrcpy(user, domuser);
                
                if ( assume_domain(lp_workgroup())) {
                        fstrcpy(domain, lp_workgroup());
                } else {
                        fstrcpy( domain, get_global_sam_name() ); 
                }
        } 
        else {
                fstrcpy(user, p+1);
                fstrcpy(domain, domuser);
                domain[PTR_DIFF(p, domuser)] = 0;
        }
        
        strupper_m(domain);
        
        return True;
}

/*
    Fill DOMAIN\\USERNAME entry accounting 'winbind use default domain' and
    'winbind separator' options.
    This means:
        - omit DOMAIN when 'winbind use default domain = true' and DOMAIN is
        lp_workgroup()

    If we are a PDC or BDC, and this is for our domain, do likewise.

    Also, if omit DOMAIN if 'winbind trusted domains only = true', as the 
    username is then unqualified in unix
         
*/
void fill_domain_username(fstring name, const char *domain, const char *user)
{
        if (assume_domain(domain)) {
                strlcpy(name, user, sizeof(fstring));
        } else {
                slprintf(name, sizeof(fstring) - 1, "%s%s%s",
                         domain, lp_winbind_separator(),
                         user);
        }
}

/*
 * Winbindd socket accessor functions
 */

char *get_winbind_priv_pipe_dir(void) 
{
        return lock_path(WINBINDD_PRIV_SOCKET_SUBDIR);
}

/* Open the winbindd socket */

static int _winbindd_socket = -1;
static int _winbindd_priv_socket = -1;

int open_winbindd_socket(void)
{
        if (_winbindd_socket == -1) {
                _winbindd_socket = create_pipe_sock(
                        WINBINDD_SOCKET_DIR, WINBINDD_SOCKET_NAME, 0755);
                DEBUG(10, ("open_winbindd_socket: opened socket fd %d\n",
                           _winbindd_socket));
        }

        return _winbindd_socket;
}

int open_winbindd_priv_socket(void)
{
        if (_winbindd_priv_socket == -1) {
                _winbindd_priv_socket = create_pipe_sock(
                        get_winbind_priv_pipe_dir(), WINBINDD_SOCKET_NAME, 0750);
                DEBUG(10, ("open_winbindd_priv_socket: opened socket fd %d\n",
                           _winbindd_priv_socket));
        }

        return _winbindd_priv_socket;
}

/* Close the winbindd socket */

void close_winbindd_socket(void)
{
        if (_winbindd_socket != -1) {
                DEBUG(10, ("close_winbindd_socket: closing socket fd %d\n",
                           _winbindd_socket));
                close(_winbindd_socket);
                _winbindd_socket = -1;
        }
        if (_winbindd_priv_socket != -1) {
                DEBUG(10, ("close_winbindd_socket: closing socket fd %d\n",
                           _winbindd_priv_socket));
                close(_winbindd_priv_socket);
                _winbindd_priv_socket = -1;
        }
}

/*
 * Client list accessor functions
 */

static struct winbindd_cli_state *_client_list;
static int _num_clients;

/* Return list of all connected clients */

struct winbindd_cli_state *winbindd_client_list(void)
{
        return _client_list;
}

/* Add a connection to the list */

void winbindd_add_client(struct winbindd_cli_state *cli)
{
        DLIST_ADD(_client_list, cli);
        _num_clients++;
}

/* Remove a client from the list */

void winbindd_remove_client(struct winbindd_cli_state *cli)
{
        DLIST_REMOVE(_client_list, cli);
        _num_clients--;
}

/* Close all open clients */

void winbindd_kill_all_clients(void)
{
        struct winbindd_cli_state *cl = winbindd_client_list();

        DEBUG(10, ("winbindd_kill_all_clients: going postal\n"));

        while (cl) {
                struct winbindd_cli_state *next;
                
                next = cl->next;
                winbindd_remove_client(cl);
                cl = next;
        }
}

/* Return number of open clients */

int winbindd_num_clients(void)
{
        return _num_clients;
}

/* Help with RID -> SID conversion */

DOM_SID *rid_to_talloced_sid(struct winbindd_domain *domain,
                                    TALLOC_CTX *mem_ctx,
                                    uint32 rid) 
{
        DOM_SID *sid;
        sid = talloc(mem_ctx, sizeof(*sid));
        if (!sid) {
                smb_panic("rid_to_to_talloced_sid: talloc for DOM_SID failed!\n");
        }
        sid_copy(sid, &domain->sid);
        sid_append_rid(sid, rid);
        return sid;
}
        
/*****************************************************************************
 For idmap conversion: convert one record to new format
 Ancient versions (eg 2.2.3a) of winbindd_idmap.tdb mapped DOMAINNAME/rid
 instead of the SID.
*****************************************************************************/
static int convert_fn(TDB_CONTEXT *tdb, TDB_DATA key, TDB_DATA data, void *state)
{
        struct winbindd_domain *domain;
        char *p;
        DOM_SID sid;
        uint32 rid;
        fstring keystr;
        fstring dom_name;
        TDB_DATA key2;
        BOOL *failed = (BOOL *)state;

        DEBUG(10,("Converting %s\n", key.dptr));

        p = strchr(key.dptr, '/');
        if (!p)
                return 0;

        *p = 0;
        fstrcpy(dom_name, key.dptr);
        *p++ = '/';

        domain = find_domain_from_name(dom_name);
        if (domain == NULL) {
                /* We must delete the old record. */
                DEBUG(0,("Unable to find domain %s\n", dom_name ));
                DEBUG(0,("deleting record %s\n", key.dptr ));

                if (tdb_delete(tdb, key) != 0) {
                        DEBUG(0, ("Unable to delete record %s\n", key.dptr));
                        *failed = True;
                        return -1;
                }

                return 0;
        }

        rid = atoi(p);

        sid_copy(&sid, &domain->sid);
        sid_append_rid(&sid, rid);

        sid_to_string(keystr, &sid);
        key2.dptr = keystr;
        key2.dsize = strlen(keystr) + 1;

        if (tdb_store(tdb, key2, data, TDB_INSERT) != 0) {
                DEBUG(0,("Unable to add record %s\n", key2.dptr ));
                *failed = True;
                return -1;
        }

        if (tdb_store(tdb, data, key2, TDB_REPLACE) != 0) {
                DEBUG(0,("Unable to update record %s\n", data.dptr ));
                *failed = True;
                return -1;
        }

        if (tdb_delete(tdb, key) != 0) {
                DEBUG(0,("Unable to delete record %s\n", key.dptr ));
                *failed = True;
                return -1;
        }

        return 0;
}

/* These definitions are from sam/idmap_tdb.c. Replicated here just
   out of laziness.... :-( */

/* High water mark keys */
#define HWM_GROUP  "GROUP HWM"
#define HWM_USER   "USER HWM"

/* idmap version determines auto-conversion */
#define IDMAP_VERSION 2


/*****************************************************************************
 Convert the idmap database from an older version.
*****************************************************************************/

static BOOL idmap_convert(const char *idmap_name)
{
        int32 vers;
        BOOL bigendianheader;
        BOOL failed = False;
        TDB_CONTEXT *idmap_tdb;

        if (!(idmap_tdb = tdb_open_log(idmap_name, 0,
                                        TDB_DEFAULT, O_RDWR,
                                        0600))) {
                DEBUG(0, ("idmap_convert: Unable to open idmap database\n"));
                return False;
        }

        bigendianheader = (idmap_tdb->flags & TDB_BIGENDIAN) ? True : False;

        vers = tdb_fetch_int32(idmap_tdb, "IDMAP_VERSION");

        if (((vers == -1) && bigendianheader) || (IREV(vers) == IDMAP_VERSION)) {
                /* Arrggghh ! Bytereversed or old big-endian - make order independent ! */
                /*
                 * high and low records were created on a
                 * big endian machine and will need byte-reversing.
                 */

                int32 wm;

                wm = tdb_fetch_int32(idmap_tdb, HWM_USER);

                if (wm != -1) {
                        wm = IREV(wm);
                }  else {
                        wm = server_state.uid_low;
                }

                if (tdb_store_int32(idmap_tdb, HWM_USER, wm) == -1) {
                        DEBUG(0, ("idmap_convert: Unable to byteswap user hwm in idmap database\n"));
                        tdb_close(idmap_tdb);
                        return False;
                }

                wm = tdb_fetch_int32(idmap_tdb, HWM_GROUP);
                if (wm != -1) {
                        wm = IREV(wm);
                } else {
                        wm = server_state.gid_low;
                }

                if (tdb_store_int32(idmap_tdb, HWM_GROUP, wm) == -1) {
                        DEBUG(0, ("idmap_convert: Unable to byteswap group hwm in idmap database\n"));
                        tdb_close(idmap_tdb);
                        return False;
                }
        }

        /* the old format stored as DOMAIN/rid - now we store the SID direct */
        tdb_traverse(idmap_tdb, convert_fn, &failed);

        if (failed) {
                DEBUG(0, ("Problem during conversion\n"));
                tdb_close(idmap_tdb);
                return False;
        }

        if (tdb_store_int32(idmap_tdb, "IDMAP_VERSION", IDMAP_VERSION) == -1) {
                DEBUG(0, ("idmap_convert: Unable to dtore idmap version in databse\n"));
                tdb_close(idmap_tdb);
                return False;
        }

        tdb_close(idmap_tdb);
        return True;
}

/*****************************************************************************
 Convert the idmap database from an older version if necessary
*****************************************************************************/

BOOL winbindd_upgrade_idmap(void)
{
        pstring idmap_name;
        pstring backup_name;
        SMB_STRUCT_STAT stbuf;
        TDB_CONTEXT *idmap_tdb;

        pstrcpy(idmap_name, lock_path("winbindd_idmap.tdb"));

        if (!file_exist(idmap_name, &stbuf)) {
                /* nothing to convert return */
                return True;
        }

        if (!(idmap_tdb = tdb_open_log(idmap_name, 0,
                                        TDB_DEFAULT, O_RDWR,
                                        0600))) {
                DEBUG(0, ("idmap_convert: Unable to open idmap database\n"));
                return False;
        }

        if (tdb_fetch_int32(idmap_tdb, "IDMAP_VERSION") == IDMAP_VERSION) {
                /* nothing to convert return */
                tdb_close(idmap_tdb);
                return True;
        }

        /* backup_tdb expects the tdb not to be open */
        tdb_close(idmap_tdb);

        DEBUG(0, ("Upgrading winbindd_idmap.tdb from an old version\n"));

        pstrcpy(backup_name, idmap_name);
        pstrcat(backup_name, ".bak");

        if (backup_tdb(idmap_name, backup_name) != 0) {
                DEBUG(0, ("Could not backup idmap database\n"));
                return False;
        }

        return idmap_convert(idmap_name);
}

/*******************************************************************
 wrapper around retrieving the trust account password
*******************************************************************/

BOOL get_trust_pw(const char *domain, uint8 ret_pwd[16],
                          time_t *pass_last_set_time, uint32 *channel)
{
        DOM_SID sid;
        char *pwd;

        /* if we are a DC and this is not our domain, then lookup an account
           for the domain trust */
           
        if ( IS_DC && !strequal(domain, lp_workgroup()) && lp_allow_trusted_domains() ) 
        {
                if ( !secrets_fetch_trusted_domain_password(domain, &pwd, &sid, 
                        pass_last_set_time) ) 
                {
                        DEBUG(0, ("get_trust_pw: could not fetch trust account "
                                  "password for trusted domain %s\n", domain));
                        return False;
                }
                
                *channel = SEC_CHAN_DOMAIN;
                E_md4hash(pwd, ret_pwd);
                SAFE_FREE(pwd);

                return True;
        }
        else    /* just get the account for our domain (covers 
                   ROLE_DOMAIN_MEMBER as well */
        {
                /* get the machine trust account for our domain */

                if ( !secrets_fetch_trust_account_password (lp_workgroup(), ret_pwd,
                        pass_last_set_time, channel) ) 
                {
                        DEBUG(0, ("get_trust_pw: could not fetch trust account "
                                  "password for my domain %s\n", domain));
                        return False;
                }
                
                return True;
        }
        
        /* Failure */
}