smbd/password.c

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/* 
   Unix SMB/CIFS implementation.
   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"

/* users from session setup */
static char *session_userlist = NULL;
static int len_session_userlist = 0;
/* workgroup from session setup. */
static char *session_workgroup = NULL;

/* 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 && usp->server_info) {
                        if (count > 10) {
                                DLIST_PROMOTE(validated_users, usp);
                        }
                        return usp;
                }
        }

        return NULL;
}

/****************************************************************************
 Get the user struct of a partial NTLMSSP login
****************************************************************************/

user_struct *get_partial_auth_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 && !usp->server_info) {
                        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;

        SAFE_FREE(vuser->homedir);
        SAFE_FREE(vuser->unix_homedir);
        SAFE_FREE(vuser->logon_script);

        if (vuser->auth_ntlmssp_state) {
                auth_ntlmssp_end(&vuser->auth_ntlmssp_state);
        }

        session_yield(vuser);
        SAFE_FREE(vuser->session_keystr);

        TALLOC_FREE(vuser->server_info);

        data_blob_free(&vuser->session_key);

        DLIST_REMOVE(validated_users, vuser);

        /* clear the vuid from the 'cache' on each connection, and
           from the vuid 'owner' of connections */
        conn_clear_vuid_cache(vuid);

        SAFE_FREE(vuser->groups);
        TALLOC_FREE(vuser->nt_user_token);

        SAFE_FREE(vuser);
        num_validated_vuids--;
}

void invalidate_intermediate_vuid(uint16 vuid)
{
        user_struct *vuser = get_partial_auth_user_struct(vuid);

        if (vuser == NULL)
                return;

        if (vuser->auth_ntlmssp_state) {
                auth_ntlmssp_end(&vuser->auth_ntlmssp_state);
        }

        DLIST_REMOVE(validated_users, vuser);

        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);
        }
}

/**
 *  register that a valid login has been performed, establish 'session'.
 *  @param server_info The token returned from the authentication process. 
 *   (now 'owned' by register_vuid)
 *
 *  @param session_key The User session key for the login session (now also
 *  'owned' by register_vuid)
 *
 *  @param respose_blob The NT challenge-response, if available.  (May be
 *  freed after this call)
 *
 *  @param smb_name The untranslated name of the user
 *
 *  @return Newly allocated vuid, biased by an offset. (This allows us to
 *   tell random client vuid's (normally zero) from valid vuids.)
 *
 */

int register_vuid(auth_serversupplied_info *server_info,
                  DATA_BLOB session_key, DATA_BLOB response_blob,
                  const char *smb_name)
{
        user_struct *vuser = NULL;

        /* Paranoia check. */
        if(lp_security() == SEC_SHARE) {
                smb_panic("Tried to register uid in security=share\n");
        }

        /* Limit allowed vuids to 16bits - VUID_OFFSET. */
        if (num_validated_vuids >= 0xFFFF-VUID_OFFSET) {
                data_blob_free(&session_key);
                TALLOC_FREE(server_info);
                return UID_FIELD_INVALID;
        }

        if((vuser = SMB_MALLOC_P(user_struct)) == NULL) {
                DEBUG(0,("Failed to malloc users struct!\n"));
                data_blob_free(&session_key);
                TALLOC_FREE(server_info);
                return UID_FIELD_INVALID;
        }

        ZERO_STRUCTP(vuser);

        /* Allocate a free vuid. Yes this is a linear search... :-) */
        while( (get_valid_user_struct(next_vuid) != NULL)
               || (get_partial_auth_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;

        if (!server_info) {
                /*
                 * This happens in an unfinished NTLMSSP session setup. We
                 * need to allocate a vuid between the first and second calls
                 * to NTLMSSP.
                 */
                next_vuid++;
                num_validated_vuids++;
                
                vuser->server_info = NULL;
                
                DLIST_ADD(validated_users, vuser);
                
                return vuser->vuid;
        }

        /* the next functions should be done by a SID mapping system (SMS) as
         * the new real sam db won't have reference to unix uids or gids
         */
        
        vuser->uid = server_info->uid;
        vuser->gid = server_info->gid;
        
        vuser->n_groups = server_info->n_groups;
        if (vuser->n_groups) {
                if (!(vuser->groups = (gid_t *)memdup(server_info->groups,
                                                      sizeof(gid_t) *
                                                      vuser->n_groups))) {
                        DEBUG(0,("register_vuid: failed to memdup "
                                 "vuser->groups\n"));
                        data_blob_free(&session_key);
                        free(vuser);
                        TALLOC_FREE(server_info);
                        return UID_FIELD_INVALID;
                }
        }

        vuser->guest = server_info->guest;
        fstrcpy(vuser->user.unix_name, server_info->unix_name); 

        /* This is a potentially untrusted username */
        alpha_strcpy(vuser->user.smb_name, smb_name, ". _-$",
                     sizeof(vuser->user.smb_name));

        fstrcpy(vuser->user.domain, pdb_get_domain(server_info->sam_account));
        fstrcpy(vuser->user.full_name,
                pdb_get_fullname(server_info->sam_account));

        {
                /* Keep the homedir handy */
                const char *homedir =
                        pdb_get_homedir(server_info->sam_account);
                const char *logon_script =
                        pdb_get_logon_script(server_info->sam_account);

                if (!IS_SAM_DEFAULT(server_info->sam_account,
                                    PDB_UNIXHOMEDIR)) {
                        const char *unix_homedir =
                                pdb_get_unix_homedir(server_info->sam_account);
                        if (unix_homedir) {
                                vuser->unix_homedir =
                                        smb_xstrdup(unix_homedir);
                        }
                } else {
                        struct passwd *passwd =
                                getpwnam_alloc(NULL, vuser->user.unix_name);
                        if (passwd) {
                                vuser->unix_homedir =
                                        smb_xstrdup(passwd->pw_dir);
                                TALLOC_FREE(passwd);
                        }
                }
                
                if (homedir) {
                        vuser->homedir = smb_xstrdup(homedir);
                }
                if (logon_script) {
                        vuser->logon_script = smb_xstrdup(logon_script);
                }
        }

        vuser->session_key = session_key;

        DEBUG(10,("register_vuid: (%u,%u) %s %s %s guest=%d\n", 
                  (unsigned int)vuser->uid, 
                  (unsigned int)vuser->gid,
                  vuser->user.unix_name, vuser->user.smb_name,
                  vuser->user.domain, vuser->guest ));

        DEBUG(3, ("User name: %s\tReal name: %s\n", vuser->user.unix_name,
                  vuser->user.full_name));      

        if (server_info->ptok) {
                vuser->nt_user_token = dup_nt_token(NULL, server_info->ptok);
        } else {
                DEBUG(1, ("server_info does not contain a user_token - "
                          "cannot continue\n"));
                TALLOC_FREE(server_info);
                data_blob_free(&session_key);
                SAFE_FREE(vuser->homedir);
                SAFE_FREE(vuser->unix_homedir);
                SAFE_FREE(vuser->logon_script);

                SAFE_FREE(vuser);
                return UID_FIELD_INVALID;
        }

        /* use this to keep tabs on all our info from the authentication */
        vuser->server_info = server_info;

        DEBUG(3,("UNIX uid %d is UNIX user %s, and will be vuid %u\n",
                 (int)vuser->uid,vuser->user.unix_name, vuser->vuid));

        next_vuid++;
        num_validated_vuids++;

        DLIST_ADD(validated_users, vuser);

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

        /* Register a home dir service for this user iff
        
           (a) This is not a guest connection,
           (b) we have a home directory defined 
           (c) there s not an existing static share by that name
           
           If a share exists by this name (autoloaded or not) reuse it . */

        vuser->homes_snum = -1;

        if ( (!vuser->guest) && vuser->unix_homedir && *(vuser->unix_homedir)) 
        {
                int servicenumber = lp_servicenumber(vuser->user.unix_name);

                if ( servicenumber == -1 ) {
                        DEBUG(3, ("Adding homes service for user '%s' using "
                                  "home directory: '%s'\n", 
                                vuser->user.unix_name, vuser->unix_homedir));
                        vuser->homes_snum =
                                add_home_service(vuser->user.unix_name, 
                                                 vuser->user.unix_name,
                                                 vuser->unix_homedir);
                } else {
                        DEBUG(3, ("Using static (or previously created) "
                                  "service for user '%s'; path = '%s'\n", 
                                  vuser->user.unix_name,
                                  lp_pathname(servicenumber) ));
                        vuser->homes_snum = servicenumber;
                }
        } 
        
        if (srv_is_signing_negotiated() && !vuser->guest &&
            !srv_signing_started()) {
                /* Try and turn on server signing on the first non-guest
                 * sessionsetup. */
                srv_set_signing(vuser->session_key, response_blob);
        }
        
        /* fill in the current_user_info struct */
        set_current_user_info( &vuser->user );


        return vuser->vuid;
}

/****************************************************************************
 Add a name to the session users list.
****************************************************************************/

void add_session_user(const char *user)
{
        fstring suser;
        struct passwd *passwd;

        if (!(passwd = Get_Pwnam(user)))
                return;

        fstrcpy(suser,passwd->pw_name);

        if(!*suser)
                return;

        if( session_userlist && in_list(suser,session_userlist,False) )
                return;

        if( !session_userlist ||
            (strlen(suser) + strlen(session_userlist) + 2 >=
             len_session_userlist) ) {
                char *newlist;

                if (len_session_userlist > 128 * PSTRING_LEN) {
                        DEBUG(3,("add_session_user: session userlist already "
                                 "too large.\n"));
                        return;
                }
                newlist = (char *)SMB_REALLOC_KEEP_OLD_ON_ERROR(
                        session_userlist,
                        len_session_userlist + PSTRING_LEN );
                if( newlist == NULL ) {
                        DEBUG(1,("Unable to resize session_userlist\n"));
                        return;
                }
                if (!session_userlist) {
                        *newlist = '\0';
                }
                session_userlist = newlist;
                len_session_userlist += PSTRING_LEN;
        }

        safe_strcat(session_userlist," ",len_session_userlist-1);
        safe_strcat(session_userlist,suser,len_session_userlist-1);
}

/****************************************************************************
 In security=share mode we need to store the client workgroup, as that's
  what Vista uses for the NTLMv2 calculation.
****************************************************************************/

void add_session_workgroup(const char *workgroup)
{
        if (session_workgroup) {
                SAFE_FREE(session_workgroup);
        }
        session_workgroup = smb_xstrdup(workgroup);
}

/****************************************************************************
 In security=share mode we need to return the client workgroup, as that's
  what Vista uses for the NTLMv2 calculation.
****************************************************************************/

const char *get_session_workgroup(void)
{
        return session_workgroup;
}

/****************************************************************************
 Check if a user is in a netgroup user list. If at first we don't succeed,
 try lower case.
****************************************************************************/

BOOL user_in_netgroup(const char *user, const char *ngname)
{
#ifdef HAVE_NETGROUP
        static char *mydomain = NULL;
        fstring lowercase_user;

        if (mydomain == NULL)
                yp_get_default_domain(&mydomain);

        if(mydomain == NULL) {
                DEBUG(5,("Unable to get default yp domain, let's try without specifying it\n"));
        }

        DEBUG(5,("looking for user %s of domain %s in netgroup %s\n",
                user, mydomain?mydomain:"(ANY)", ngname));

        if (innetgr(ngname, NULL, user, mydomain)) {
                DEBUG(5,("user_in_netgroup: Found\n"));
                return (True);
        } else {

                /*
                 * Ok, innetgr is case sensitive. Try once more with lowercase
                 * just in case. Attempt to fix #703. JRA.
                 */

                fstrcpy(lowercase_user, user);
                strlower_m(lowercase_user);
        
                DEBUG(5,("looking for user %s of domain %s in netgroup %s\n",
                        lowercase_user, mydomain?mydomain:"(ANY)", ngname));

                if (innetgr(ngname, NULL, lowercase_user, mydomain)) {
                        DEBUG(5,("user_in_netgroup: Found\n"));
                        return (True);
                }
        }
#endif /* HAVE_NETGROUP */
        return False;
}

/****************************************************************************
 Check if a user is in a user list - can check combinations of UNIX
 and netgroup lists.
****************************************************************************/

BOOL user_in_list(const char *user,const char **list)
{
        if (!list || !*list)
                return False;

        DEBUG(10,("user_in_list: checking user %s in list\n", user));

        while (*list) {

                DEBUG(10,("user_in_list: checking user |%s| against |%s|\n",
                          user, *list));

                /*
                 * Check raw username.
                 */
                if (strequal(user, *list))
                        return(True);

                /*
                 * Now check to see if any combination
                 * of UNIX and netgroups has been specified.
                 */

                if(**list == '@') {
                        /*
                         * Old behaviour. Check netgroup list
                         * followed by UNIX list.
                         */
                        if(user_in_netgroup(user, *list +1))
                                return True;
                        if(user_in_group(user, *list +1))
                                return True;
                } else if (**list == '+') {

                        if((*(*list +1)) == '&') {
                                /*
                                 * Search UNIX list followed by netgroup.
                                 */
                                if(user_in_group(user, *list +2))
                                        return True;
                                if(user_in_netgroup(user, *list +2))
                                        return True;

                        } else {

                                /*
                                 * Just search UNIX list.
                                 */

                                if(user_in_group(user, *list +1))
                                        return True;
                        }

                } else if (**list == '&') {

                        if(*(*list +1) == '+') {
                                /*
                                 * Search netgroup list followed by UNIX list.
                                 */
                                if(user_in_netgroup(user, *list +2))
                                        return True;
                                if(user_in_group(user, *list +2))
                                        return True;
                        } else {
                                /*
                                 * Just search netgroup list.
                                 */
                                if(user_in_netgroup(user, *list +1))
                                        return True;
                        }
                }
    
                list++;
        }
        return(False);
}

/****************************************************************************
 Check if a username is valid.
****************************************************************************/

static BOOL user_ok(const char *user, int snum)
{
        char **valid, **invalid;
        BOOL ret;

        valid = invalid = NULL;
        ret = True;

        if (lp_invalid_users(snum)) {
                str_list_copy(&invalid, lp_invalid_users(snum));
                if (invalid &&
                    str_list_substitute(invalid, "%S", lp_servicename(snum))) {

                        /* This is used in sec=share only, so no current user
                         * around to pass to str_list_sub_basic() */

                        if ( invalid && str_list_sub_basic(invalid, "", "") ) {
                                ret = !user_in_list(user,
                                                    (const char **)invalid);
                        }
                }
        }
        if (invalid)
                str_list_free (&invalid);

        if (ret && lp_valid_users(snum)) {
                str_list_copy(&valid, lp_valid_users(snum));
                if ( valid &&
                     str_list_substitute(valid, "%S", lp_servicename(snum)) ) {

                        /* This is used in sec=share only, so no current user
                         * around to pass to str_list_sub_basic() */

                        if ( valid && str_list_sub_basic(valid, "", "") ) {
                                ret = user_in_list(user, (const char **)valid);
                        }
                }
        }
        if (valid)
                str_list_free (&valid);

        if (ret && lp_onlyuser(snum)) {
                char **user_list = str_list_make (lp_username(snum), NULL);
                if (user_list &&
                    str_list_substitute(user_list, "%S",
                                        lp_servicename(snum))) {
                        ret = user_in_list(user, (const char **)user_list);
                }
                if (user_list) str_list_free (&user_list);
        }

        return(ret);
}

/****************************************************************************
 Validate a group username entry. Return the username or NULL.
****************************************************************************/

static char *validate_group(char *group, DATA_BLOB password,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)) {
                                        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)) {
                                        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.
 Note this is *NOT* used when logging on using sessionsetup_and_X.
****************************************************************************/

BOOL authorise_login(int snum, fstring user, DATA_BLOB password, 
                     BOOL *guest)
{
        BOOL ok = False;
        
#ifdef DEBUG_PASSWORD
        DEBUG(100,("authorise_login: checking authorisation on "
                   "user=%s pass=%s\n", user,password.data));
#endif

        *guest = False;
  
        /* 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
        */

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

                if ( session_userlist )
                        user_list = SMB_STRDUP(session_userlist);
                else
                        user_list = SMB_STRDUP("");

                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)) {
                                ok = True;
                                fstrcpy(user,user2);
                                DEBUG(3,("authorise_login: ACCEPTED: session "
                                         "list username (%s) and given "
                                         "password ok\n", user));
                        }
                }

                SAFE_FREE(user_list);
        }
        
        /* check the user= fields and the given password */
        if (!ok && lp_username(snum)) {
                char *auser;
                pstring user_list;
                pstrcpy(user_list,lp_username(snum));
                
                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,snum);
                                if (auser) {
                                        ok = True;
                                        fstrcpy(user,auser);
                                        DEBUG(3,("authorise_login: ACCEPTED: "
                                                 "group username and given "
                                                 "password ok (%s)\n", user));
                                }
                        } else {
                                fstring user2;
                                fstrcpy(user2,auser);
                                if (user_ok(user2,snum) &&
                                    password_ok(user2,password)) {
                                        ok = True;
                                        fstrcpy(user,user2);
                                        DEBUG(3,("authorise_login: ACCEPTED: "
                                                 "user list username and "
                                                 "given password ok (%s)\n",
                                                 user));
                                }
                        }
                }
        }

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

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

        return(ok);
}

---