don't dereference null pointer

[Samba/gebeck_regimport.git] / source4 / 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 "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)
                init_domain_list();

        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;
        
        /* 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 (strcasecmp(domain_name, domain->name) == 0 ||
                    strcasecmp(domain_name, domain->alt_name) == 0) {
                        return domain;
                }
                if (alt_name && *alt_name) {
                        if (strcasecmp(alt_name, domain->name) == 0 ||
                            strcasecmp(alt_name, domain->alt_name) == 0) {
                                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, '.') && alt_name && *alt_name) {
                fstrcpy(domain->name, alt_name);
                fstrcpy(domain->alt_name, domain_name);
        } else {
        fstrcpy(domain->name, domain_name);
                if (alt_name) {
                        fstrcpy(domain->alt_name, alt_name);
                }
        }

        domain->methods = methods;
        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, but only for our own domain */
           
        if ( strequal( lp_workgroup(), domain_name) )   {
                domain->native_mode = cm_check_for_native_mode_win2k( domain_name );
                DEBUG(3,("add_trusted_domain: %s is a %s mode domain\n", domain_name,
                                        domain->native_mode ? "native" : "mixed" ));
        }       

        /* 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;
}


/*
  rescan our domains looking for new trusted domains
 */
void rescan_trusted_domains(BOOL force)
{
        struct winbindd_domain *domain;
        TALLOC_CTX *mem_ctx;
        static time_t last_scan;
        time_t t = time(NULL);

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

        /* Only rescan every few minutes but force if necessary */

        if (((unsigned)(t - last_scan) < WINBINDD_RESCAN_FREQ) && !force)
                return;

        last_scan = t;

        DEBUG(1, ("scanning trusted domain list\n"));

        if (!(mem_ctx = talloc_init("init_domain_list")))
                return;

        for (domain = _domain_list; domain; domain = domain->next) {
                NTSTATUS result;
                char **names;
                char **alt_names;
                int num_domains = 0;
                DOM_SID *dom_sids;
                int i;

                result = domain->methods->trusted_domains(domain, mem_ctx, &num_domains,
                                                          &names, &alt_names, &dom_sids);
                if (!NT_STATUS_IS_OK(result)) {
                        continue;
                }

                /* Add each domain to the trusted domain list. Each domain inherits
                   the access methods of its parent */
                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]);
                        
                        /* store trusted domain in the cache */
                        trustdom_cache_store(mem_ctx, 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 */
        domain = add_trusted_domain(lp_workgroup(), NULL, &cache_methods, NULL);
        if (!secrets_fetch_domain_sid(domain->name, &domain->sid)) {
                DEBUG(1, ("Could not fetch sid for our domain %s\n",
                          domain->name));
                return False;
        }

        /* get any alternate name for the primary domain */
        cache_methods.alternate_name(domain);

        /* do an initial scan for trusted domains */
        rescan_trusted_domains(True);

        return True;
}

/* Given a domain name, return the struct winbindd domain info for it 
   if it is actually 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;
}

/* 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;
        /* Don't bother with machine accounts */

        if (name[strlen(name) - 1] == '$')
                return False;

        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_winbind_uid(&server_state.uid_low, &server_state.uid_high)) {
                DEBUG(0, ("winbind uid range missing or invalid\n"));
                return False;
        }
        
        if (!lp_winbind_gid(&server_state.gid_low, &server_state.gid_high)) {
                DEBUG(0, ("winbind gid range missing or invalid\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;
}

/* 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 || lp_winbind_use_default_domain()))
                return False;
        
        if(!p && lp_winbind_use_default_domain()) {
                fstrcpy(user, domuser);
                fstrcpy(domain, lp_workgroup());
        } else {
                fstrcpy(user, p+1);
                fstrcpy(domain, domuser);
                domain[PTR_DIFF(p, domuser)] = 0;
        }
        strupper(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
         
*/
void fill_domain_username(fstring name, const char *domain, const char *user)
{
        if(lp_winbind_use_default_domain() &&
            !strcmp(lp_workgroup(), domain)) {
                strlcpy(name, user, sizeof(fstring));
        } else {
                slprintf(name, sizeof(fstring) - 1, "%s%s%s",
                         domain, lp_winbind_separator(),
                         user);
        }
}

/*
 * Winbindd socket accessor functions
 */

/* Open the winbindd socket */

static int _winbindd_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;
}

/* 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;
        }
}

/*
 * 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;
}