smbd/session.c

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/* 
   Unix SMB/CIFS implementation.
   session handling for utmp and PAM

   Copyright (C) tridge@samba.org       2001
   Copyright (C) abartlet@samba.org     2001
   Copyright (C) Gerald (Jerry) Carter  2006   
   
   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.
*/

/* a "session" is claimed when we do a SessionSetupX operation
   and is yielded when the corresponding vuid is destroyed.

   sessions are used to populate utmp and PAM session structures
*/

#include "includes.h"

static TDB_CONTEXT *tdb;

/********************************************************************
********************************************************************/

BOOL session_init(void)
{
        if (tdb)
                return True;

        tdb = tdb_open_log(lock_path("sessionid.tdb"), 0, TDB_CLEAR_IF_FIRST|TDB_DEFAULT, 
                       O_RDWR | O_CREAT, 0644);
        if (!tdb) {
                DEBUG(1,("session_init: failed to open sessionid tdb\n"));
                return False;
        }

        return True;
}

/********************************************************************
 called when a session is created
********************************************************************/

BOOL session_claim(user_struct *vuser)
{
        int i = 0;
        TDB_DATA data;
        struct sockaddr sa;
        struct in_addr *client_ip;
        struct sessionid sessionid;
        uint32 pid = (uint32)sys_getpid();
        TDB_DATA key;           
        fstring keystr;
        char * hostname;
        int tdb_store_flag;  /* If using utmp, we do an inital 'lock hold' store,
                                but we don't need this if we are just using the 
                                (unique) pid/vuid combination */

        vuser->session_keystr = NULL;

        /* don't register sessions for the guest user - its just too
           expensive to go through pam session code for browsing etc */
        if (vuser->guest) {
                return True;
        }

        if (!session_init())
                return False;

        ZERO_STRUCT(sessionid);

        data.dptr = NULL;
        data.dsize = 0;

        if (lp_utmp()) {
                for (i=1;i<MAX_SESSION_ID;i++) {
                        slprintf(keystr, sizeof(keystr)-1, "ID/%d", i);
                        key.dptr = keystr;
                        key.dsize = strlen(keystr)+1;
                        
                        if (tdb_store(tdb, key, data, TDB_INSERT) == 0) break;
                }
                
                if (i == MAX_SESSION_ID) {
                        DEBUG(1,("session_claim: out of session IDs (max is %d)\n", 
                                 MAX_SESSION_ID));
                        return False;
                }
                slprintf(sessionid.id_str, sizeof(sessionid.id_str)-1, SESSION_UTMP_TEMPLATE, i);
                tdb_store_flag = TDB_MODIFY;
        } else
        {
                slprintf(keystr, sizeof(keystr)-1, "ID/%lu/%u", 
                         (long unsigned int)sys_getpid(), 
                         vuser->vuid);
                slprintf(sessionid.id_str, sizeof(sessionid.id_str)-1, 
                         SESSION_TEMPLATE, (long unsigned int)sys_getpid(), 
                         vuser->vuid);

                key.dptr = keystr;
                key.dsize = strlen(keystr)+1;
                        
                tdb_store_flag = TDB_REPLACE;
        }

        /* If 'hostname lookup' == yes, then do the DNS lookup.  This is
           needed because utmp and PAM both expect DNS names 
           
           client_name() handles this case internally.
        */

        hostname = client_name();
        if (strcmp(hostname, "UNKNOWN") == 0) {
                hostname = client_addr();
        }

        fstrcpy(sessionid.username, vuser->user.unix_name);
        fstrcpy(sessionid.hostname, hostname);
        sessionid.id_num = i;  /* Only valid for utmp sessions */
        sessionid.pid = pid;
        sessionid.uid = vuser->uid;
        sessionid.gid = vuser->gid;
        fstrcpy(sessionid.remote_machine, get_remote_machine_name());
        fstrcpy(sessionid.ip_addr, client_addr());
        sessionid.connect_start = time(NULL);

        client_ip = client_inaddr(&sa);

        if (!smb_pam_claim_session(sessionid.username, sessionid.id_str, sessionid.hostname)) {
                DEBUG(1,("pam_session rejected the session for %s [%s]\n",
                                sessionid.username, sessionid.id_str));
                if (tdb_store_flag == TDB_MODIFY) {
                        tdb_delete(tdb, key);
                }
                return False;
        }

        data.dptr = (char *)&sessionid;
        data.dsize = sizeof(sessionid);
        if (tdb_store(tdb, key, data, tdb_store_flag) != 0) {
                DEBUG(1,("session_claim: unable to create session id record\n"));
                return False;
        }

        if (lp_utmp()) {
                sys_utmp_claim(sessionid.username, sessionid.hostname, 
                               client_ip,
                               sessionid.id_str, sessionid.id_num);
        }

        vuser->session_keystr = SMB_STRDUP(keystr);
        if (!vuser->session_keystr) {
                DEBUG(0, ("session_claim:  strdup() failed for session_keystr\n"));
                return False;
        }
        return True;
}

/********************************************************************
 called when a session is destroyed
********************************************************************/

void session_yield(user_struct *vuser)
{
        TDB_DATA dbuf;
        struct sessionid sessionid;
        struct in_addr *client_ip;
        TDB_DATA key;

        if (!tdb) return;

        if (!vuser->session_keystr) {
                return;
        }

        key.dptr = vuser->session_keystr;
        key.dsize = strlen(vuser->session_keystr)+1;

        dbuf = tdb_fetch(tdb, key);

        if (dbuf.dsize != sizeof(sessionid))
                return;

        memcpy(&sessionid, dbuf.dptr, sizeof(sessionid));

        client_ip = interpret_addr2(sessionid.ip_addr);

        SAFE_FREE(dbuf.dptr);

        if (lp_utmp()) {
                sys_utmp_yield(sessionid.username, sessionid.hostname, 
                               client_ip,
                               sessionid.id_str, sessionid.id_num);
        }

        smb_pam_close_session(sessionid.username, sessionid.id_str, sessionid.hostname);

        tdb_delete(tdb, key);
}

/********************************************************************
********************************************************************/

BOOL session_traverse(int (*fn)(TDB_CONTEXT *, TDB_DATA, TDB_DATA, void *),
                      void *state)
{
        if (!session_init()) {
                DEBUG(3, ("No tdb opened\n"));
                return False;
        }

        tdb_traverse(tdb, fn, state);
        return True;
}

/********************************************************************
********************************************************************/

struct session_list {
        int count;
        struct sessionid *sessions;
};

static int gather_sessioninfo(TDB_CONTEXT *stdb, TDB_DATA kbuf, TDB_DATA dbuf, void *state)
{
        uint32 i;       
        struct session_list *sesslist = (struct session_list *) state;
        const struct sessionid *current = (const struct sessionid *) dbuf.dptr;

        i = sesslist->count;
        
        sesslist->sessions = SMB_REALLOC_ARRAY(sesslist->sessions, struct sessionid, i+1);
        if (!sesslist->sessions) {
                sesslist->count = 0;
                return -1;
        }

        memcpy(&sesslist->sessions[i], current, sizeof(struct sessionid));
        sesslist->count++;

        DEBUG(7,("gather_sessioninfo session from %s@%s\n", 
                 current->username, current->remote_machine));

        return 0;
}

/********************************************************************
********************************************************************/

int list_sessions(struct sessionid **session_list)
{
        struct session_list sesslist;

        sesslist.count = 0;
        sesslist.sessions = NULL;
        
        if (!session_traverse(gather_sessioninfo, (void *) &sesslist)) {
                DEBUG(3, ("Session traverse failed\n"));
                SAFE_FREE(sesslist.sessions);
                *session_list = NULL;
                return 0;
        }

        *session_list = sesslist.sessions;
        return sesslist.count;
}

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