auth/pampass.c

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/* 
   Unix SMB/CIFS implementation.
   PAM Password checking
   Copyright (C) Andrew Tridgell 1992-2001
   Copyright (C) John H Terpsta 1999-2001
   Copyright (C) Andrew Bartlett 2001
   Copyright (C) Jeremy Allison 2001
   
   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.
*/

/*
 * This module provides PAM based functions for validation of
 * username/password pairs, account managment, session and access control.
 * Note: SMB password checking is done in smbpass.c
 */

#include "includes.h"

#undef DBGC_CLASS
#define DBGC_CLASS DBGC_AUTH

#ifdef WITH_PAM

/*******************************************************************
 * Handle PAM authentication 
 *      - Access, Authentication, Session, Password
 *   Note: See PAM Documentation and refer to local system PAM implementation
 *   which determines what actions/limitations/allowances become affected.
 *********************************************************************/

#include <security/pam_appl.h>

/*
 * Structure used to communicate between the conversation function
 * and the server_login/change password functions.
 */

struct smb_pam_userdata {
        const char *PAM_username;
        const char *PAM_password;
        const char *PAM_newpassword;
};

typedef int (*smb_pam_conv_fn)(int, const struct pam_message **, struct pam_response **, void *appdata_ptr);

/*
 *  Macros to help make life easy
 */
#define COPY_STRING(s) (s) ? SMB_STRDUP(s) : NULL

/*******************************************************************
 PAM error handler.
 *********************************************************************/

static BOOL smb_pam_error_handler(pam_handle_t *pamh, int pam_error, const char *msg, int dbglvl)
{

        if( pam_error != PAM_SUCCESS) {
                DEBUG(dbglvl, ("smb_pam_error_handler: PAM: %s : %s\n",
                                msg, pam_strerror(pamh, pam_error)));
                
                return False;
        }
        return True;
}

/*******************************************************************
 This function is a sanity check, to make sure that we NEVER report
 failure as sucess.
*********************************************************************/

static BOOL smb_pam_nt_status_error_handler(pam_handle_t *pamh, int pam_error,
                                            const char *msg, int dbglvl, 
                                            NTSTATUS *nt_status)
{
        *nt_status = pam_to_nt_status(pam_error);

        if (smb_pam_error_handler(pamh, pam_error, msg, dbglvl))
                return True;

        if (NT_STATUS_IS_OK(*nt_status)) {
                /* Complain LOUDLY */
                DEBUG(0, ("smb_pam_nt_status_error_handler: PAM: BUG: PAM and NT_STATUS \
error MISMATCH, forcing to NT_STATUS_LOGON_FAILURE"));
                *nt_status = NT_STATUS_LOGON_FAILURE;
        }
        return False;
}

/*
 * PAM conversation function
 * Here we assume (for now, at least) that echo on means login name, and
 * echo off means password.
 */

static int smb_pam_conv(int num_msg,
                    const struct pam_message **msg,
                    struct pam_response **resp,
                    void *appdata_ptr)
{
        int replies = 0;
        struct pam_response *reply = NULL;
        struct smb_pam_userdata *udp = (struct smb_pam_userdata *)appdata_ptr;

        *resp = NULL;

        if (num_msg <= 0)
                return PAM_CONV_ERR;

        /*
         * Apparantly HPUX has a buggy PAM that doesn't support the
         * appdata_ptr. Fail if this is the case. JRA.
         */

        if (udp == NULL) {
                DEBUG(0,("smb_pam_conv: PAM on this system is broken - appdata_ptr == NULL !\n"));
                return PAM_CONV_ERR;
        }

        reply = SMB_MALLOC_ARRAY(struct pam_response, num_msg);
        if (!reply)
                return PAM_CONV_ERR;

        memset(reply, '\0', sizeof(struct pam_response) * num_msg);

        for (replies = 0; replies < num_msg; replies++) {
                switch (msg[replies]->msg_style) {
                        case PAM_PROMPT_ECHO_ON:
                                reply[replies].resp_retcode = PAM_SUCCESS;
                                reply[replies].resp = COPY_STRING(udp->PAM_username);
                                /* PAM frees resp */
                                break;

                        case PAM_PROMPT_ECHO_OFF:
                                reply[replies].resp_retcode = PAM_SUCCESS;
                                reply[replies].resp = COPY_STRING(udp->PAM_password);
                                /* PAM frees resp */
                                break;

                        case PAM_TEXT_INFO:
                                /* fall through */

                        case PAM_ERROR_MSG:
                                /* ignore it... */
                                reply[replies].resp_retcode = PAM_SUCCESS;
                                reply[replies].resp = NULL;
                                break;

                        default:
                                /* Must be an error of some sort... */
                                SAFE_FREE(reply);
                                return PAM_CONV_ERR;
                }
        }
        if (reply)
                *resp = reply;
        return PAM_SUCCESS;
}

/*
 * PAM password change conversation function
 * Here we assume (for now, at least) that echo on means login name, and
 * echo off means password.
 */

static void special_char_sub(char *buf)
{
        all_string_sub(buf, "\\n", "", 0);
        all_string_sub(buf, "\\r", "", 0);
        all_string_sub(buf, "\\s", " ", 0);
        all_string_sub(buf, "\\t", "\t", 0);
}

static void pwd_sub(char *buf, const char *username, const char *oldpass, const char *newpass)
{
        fstring_sub(buf, "%u", username);
        all_string_sub(buf, "%o", oldpass, sizeof(fstring));
        all_string_sub(buf, "%n", newpass, sizeof(fstring));
}


struct chat_struct {
        struct chat_struct *next, *prev;
        fstring prompt;
        fstring reply;
};

/**************************************************************
 Create a linked list containing chat data.
***************************************************************/

static struct chat_struct *make_pw_chat(const char *p) 
{
        fstring prompt;
        fstring reply;
        struct chat_struct *list = NULL;
        struct chat_struct *t;

        while (1) {
                t = SMB_MALLOC_P(struct chat_struct);
                if (!t) {
                        DEBUG(0,("make_pw_chat: malloc failed!\n"));
                        return NULL;
                }

                ZERO_STRUCTP(t);

                DLIST_ADD_END(list, t, struct chat_struct*);

                if (!next_token(&p, prompt, NULL, sizeof(fstring)))
                        break;

                if (strequal(prompt,"."))
                        fstrcpy(prompt,"*");

                special_char_sub(prompt);
                fstrcpy(t->prompt, prompt);
                strlower_m(t->prompt);
                trim_char(t->prompt, ' ', ' ');

                if (!next_token(&p, reply, NULL, sizeof(fstring)))
                        break;

                if (strequal(reply,"."))
                                fstrcpy(reply,"");

                special_char_sub(reply);
                fstrcpy(t->reply, reply);
                strlower_m(t->reply);
                trim_char(t->reply, ' ', ' ');

        }
        return list;
}

static void free_pw_chat(struct chat_struct *list)
{
    while (list) {
        struct chat_struct *old_head = list;
        DLIST_REMOVE(list, list);
        SAFE_FREE(old_head);
    }
}

static int smb_pam_passchange_conv(int num_msg,
                                const struct pam_message **msg,
                                struct pam_response **resp,
                                void *appdata_ptr)
{
        int replies = 0;
        struct pam_response *reply = NULL;
        fstring current_prompt;
        fstring current_reply;
        struct smb_pam_userdata *udp = (struct smb_pam_userdata *)appdata_ptr;
        struct chat_struct *pw_chat= make_pw_chat(lp_passwd_chat());
        struct chat_struct *t;
        BOOL found; 
        *resp = NULL;
        
        DEBUG(10,("smb_pam_passchange_conv: starting converstation for %d messages\n", num_msg));

        if (num_msg <= 0)
                return PAM_CONV_ERR;

        if (pw_chat == NULL)
                return PAM_CONV_ERR;

        /*
         * Apparantly HPUX has a buggy PAM that doesn't support the
         * appdata_ptr. Fail if this is the case. JRA.
         */

        if (udp == NULL) {
                DEBUG(0,("smb_pam_passchange_conv: PAM on this system is broken - appdata_ptr == NULL !\n"));
                free_pw_chat(pw_chat);
                return PAM_CONV_ERR;
        }

        reply = SMB_MALLOC_ARRAY(struct pam_response, num_msg);
        if (!reply) {
                DEBUG(0,("smb_pam_passchange_conv: malloc for reply failed!\n"));
                free_pw_chat(pw_chat);
                return PAM_CONV_ERR;
        }

        for (replies = 0; replies < num_msg; replies++) {
                found = False;
                DEBUG(10,("smb_pam_passchange_conv: Processing message %d\n", replies));
                switch (msg[replies]->msg_style) {
                case PAM_PROMPT_ECHO_ON:
                        DEBUG(10,("smb_pam_passchange_conv: PAM_PROMPT_ECHO_ON: PAM said: %s\n", msg[replies]->msg));
                        fstrcpy(current_prompt, msg[replies]->msg);
                        trim_char(current_prompt, ' ', ' ');
                        for (t=pw_chat; t; t=t->next) {

                                DEBUG(10,("smb_pam_passchange_conv: PAM_PROMPT_ECHO_ON: trying to match |%s| to |%s|\n",
                                                t->prompt, current_prompt ));

                                if (unix_wild_match(t->prompt, current_prompt)) {
                                        fstrcpy(current_reply, t->reply);
                                        DEBUG(10,("smb_pam_passchange_conv: PAM_PROMPT_ECHO_ON: We sent: %s\n", current_reply));
                                        pwd_sub(current_reply, udp->PAM_username, udp->PAM_password, udp->PAM_newpassword);
#ifdef DEBUG_PASSWORD
                                        DEBUG(100,("smb_pam_passchange_conv: PAM_PROMPT_ECHO_ON: We actualy sent: %s\n", current_reply));
#endif
                                        reply[replies].resp_retcode = PAM_SUCCESS;
                                        reply[replies].resp = COPY_STRING(current_reply);
                                        found = True;
                                        break;
                                }
                        }
                        /* PAM frees resp */
                        if (!found) {
                                DEBUG(3,("smb_pam_passchange_conv: Could not find reply for PAM prompt: %s\n",msg[replies]->msg));
                                free_pw_chat(pw_chat);
                                SAFE_FREE(reply);
                                return PAM_CONV_ERR;
                        }
                        break;

                case PAM_PROMPT_ECHO_OFF:
                        DEBUG(10,("smb_pam_passchange_conv: PAM_PROMPT_ECHO_OFF: PAM said: %s\n", msg[replies]->msg));
                        fstrcpy(current_prompt, msg[replies]->msg);
                        trim_char(current_prompt, ' ', ' ');
                        for (t=pw_chat; t; t=t->next) {

                                DEBUG(10,("smb_pam_passchange_conv: PAM_PROMPT_ECHO_OFF: trying to match |%s| to |%s|\n",
                                                t->prompt, current_prompt ));

                                if (unix_wild_match(t->prompt, current_prompt)) {
                                        fstrcpy(current_reply, t->reply);
                                        DEBUG(10,("smb_pam_passchange_conv: PAM_PROMPT_ECHO_OFF: We sent: %s\n", current_reply));
                                        pwd_sub(current_reply, udp->PAM_username, udp->PAM_password, udp->PAM_newpassword);
                                        reply[replies].resp_retcode = PAM_SUCCESS;
                                        reply[replies].resp = COPY_STRING(current_reply);
#ifdef DEBUG_PASSWORD
                                        DEBUG(100,("smb_pam_passchange_conv: PAM_PROMPT_ECHO_OFF: We actualy sent: %s\n", current_reply));
#endif
                                        found = True;
                                        break;
                                }
                        }
                        /* PAM frees resp */
                        
                        if (!found) {
                                DEBUG(3,("smb_pam_passchange_conv: Could not find reply for PAM prompt: %s\n",msg[replies]->msg));
                                free_pw_chat(pw_chat);
                                SAFE_FREE(reply);
                                return PAM_CONV_ERR;
                        }
                        break;

                case PAM_TEXT_INFO:
                        /* fall through */

                case PAM_ERROR_MSG:
                        /* ignore it... */
                        reply[replies].resp_retcode = PAM_SUCCESS;
                        reply[replies].resp = NULL;
                        break;
                        
                default:
                        /* Must be an error of some sort... */
                        free_pw_chat(pw_chat);
                        SAFE_FREE(reply);
                        return PAM_CONV_ERR;
                }
        }
                
        free_pw_chat(pw_chat);
        if (reply)
                *resp = reply;
        return PAM_SUCCESS;
}

/***************************************************************************
 Free up a malloced pam_conv struct.
****************************************************************************/

static void smb_free_pam_conv(struct pam_conv *pconv)
{
        if (pconv)
                SAFE_FREE(pconv->appdata_ptr);

        SAFE_FREE(pconv);
}

/***************************************************************************
 Allocate a pam_conv struct.
****************************************************************************/

static struct pam_conv *smb_setup_pam_conv(smb_pam_conv_fn smb_pam_conv_fnptr, const char *user,
                                        const char *passwd, const char *newpass)
{
        struct pam_conv *pconv = SMB_MALLOC_P(struct pam_conv);
        struct smb_pam_userdata *udp = SMB_MALLOC_P(struct smb_pam_userdata);

        if (pconv == NULL || udp == NULL) {
                SAFE_FREE(pconv);
                SAFE_FREE(udp);
                return NULL;
        }

        udp->PAM_username = user;
        udp->PAM_password = passwd;
        udp->PAM_newpassword = newpass;

        pconv->conv = smb_pam_conv_fnptr;
        pconv->appdata_ptr = (void *)udp;
        return pconv;
}

/* 
 * PAM Closing out cleanup handler
 */

static BOOL smb_pam_end(pam_handle_t *pamh, struct pam_conv *smb_pam_conv_ptr)
{
        int pam_error;

        smb_free_pam_conv(smb_pam_conv_ptr);
       
        if( pamh != NULL ) {
                pam_error = pam_end(pamh, 0);
                if(smb_pam_error_handler(pamh, pam_error, "End Cleanup Failed", 2) == True) {
                        DEBUG(4, ("smb_pam_end: PAM: PAM_END OK.\n"));
                        return True;
                }
        }
        DEBUG(2,("smb_pam_end: PAM: not initialised"));
        return False;
}

/*
 * Start PAM authentication for specified account
 */

static BOOL smb_pam_start(pam_handle_t **pamh, const char *user, const char *rhost, struct pam_conv *pconv)
{
        int pam_error;
        const char *our_rhost;

        *pamh = (pam_handle_t *)NULL;

        DEBUG(4,("smb_pam_start: PAM: Init user: %s\n", user));

        pam_error = pam_start("samba", user, pconv, pamh);
        if( !smb_pam_error_handler(*pamh, pam_error, "Init Failed", 0)) {
                *pamh = (pam_handle_t *)NULL;
                return False;
        }

        if (rhost == NULL) {
                our_rhost = client_name();
                if (strequal(our_rhost,"UNKNOWN"))
                        our_rhost = client_addr();
        } else {
                our_rhost = rhost;
        }

#ifdef PAM_RHOST
        DEBUG(4,("smb_pam_start: PAM: setting rhost to: %s\n", our_rhost));
        pam_error = pam_set_item(*pamh, PAM_RHOST, our_rhost);
        if(!smb_pam_error_handler(*pamh, pam_error, "set rhost failed", 0)) {
                smb_pam_end(*pamh, pconv);
                *pamh = (pam_handle_t *)NULL;
                return False;
        }
#endif
#ifdef PAM_TTY
        DEBUG(4,("smb_pam_start: PAM: setting tty\n"));
        pam_error = pam_set_item(*pamh, PAM_TTY, "samba");
        if (!smb_pam_error_handler(*pamh, pam_error, "set tty failed", 0)) {
                smb_pam_end(*pamh, pconv);
                *pamh = (pam_handle_t *)NULL;
                return False;
        }
#endif
        DEBUG(4,("smb_pam_start: PAM: Init passed for user: %s\n", user));
        return True;
}

/*
 * PAM Authentication Handler
 */
static NTSTATUS smb_pam_auth(pam_handle_t *pamh, const char *user)
{
        int pam_error;
        NTSTATUS nt_status = NT_STATUS_LOGON_FAILURE;

        /*
         * To enable debugging set in /etc/pam.d/samba:
         *      auth required /lib/security/pam_pwdb.so nullok shadow audit
         */
        
        DEBUG(4,("smb_pam_auth: PAM: Authenticate User: %s\n", user));
        pam_error = pam_authenticate(pamh, PAM_SILENT | lp_null_passwords() ? 0 : PAM_DISALLOW_NULL_AUTHTOK);
        switch( pam_error ){
                case PAM_AUTH_ERR:
                        DEBUG(2, ("smb_pam_auth: PAM: Authentication Error for user %s\n", user));
                        break;
                case PAM_CRED_INSUFFICIENT:
                        DEBUG(2, ("smb_pam_auth: PAM: Insufficient Credentials for user %s\n", user));
                        break;
                case PAM_AUTHINFO_UNAVAIL:
                        DEBUG(2, ("smb_pam_auth: PAM: Authentication Information Unavailable for user %s\n", user));
                        break;
                case PAM_USER_UNKNOWN:
                        DEBUG(2, ("smb_pam_auth: PAM: Username %s NOT known to Authentication system\n", user));
                        break;
                case PAM_MAXTRIES:
                        DEBUG(2, ("smb_pam_auth: PAM: One or more authentication modules reports user limit for user %s exceeeded\n", user));
                        break;
                case PAM_ABORT:
                        DEBUG(0, ("smb_pam_auth: PAM: One or more PAM modules failed to load for user %s\n", user));
                        break;
                case PAM_SUCCESS:
                        DEBUG(4, ("smb_pam_auth: PAM: User %s Authenticated OK\n", user));
                        break;
                default:
                        DEBUG(0, ("smb_pam_auth: PAM: UNKNOWN ERROR while authenticating user %s\n", user));
                        break;
        }

        smb_pam_nt_status_error_handler(pamh, pam_error, "Authentication Failure", 2, &nt_status);
        return nt_status;
}

/* 
 * PAM Account Handler
 */
static NTSTATUS smb_pam_account(pam_handle_t *pamh, const char * user)
{
        int pam_error;
        NTSTATUS nt_status = NT_STATUS_ACCOUNT_DISABLED;

        DEBUG(4,("smb_pam_account: PAM: Account Management for User: %s\n", user));
        pam_error = pam_acct_mgmt(pamh, PAM_SILENT); /* Is user account enabled? */
        switch( pam_error ) {
                case PAM_AUTHTOK_EXPIRED:
                        DEBUG(2, ("smb_pam_account: PAM: User %s is valid but password is expired\n", user));
                        break;
                case PAM_ACCT_EXPIRED:
                        DEBUG(2, ("smb_pam_account: PAM: User %s no longer permitted to access system\n", user));
                        break;
                case PAM_AUTH_ERR:
                        DEBUG(2, ("smb_pam_account: PAM: There was an authentication error for user %s\n", user));
                        break;
                case PAM_PERM_DENIED:
                        DEBUG(0, ("smb_pam_account: PAM: User %s is NOT permitted to access system at this time\n", user));
                        break;
                case PAM_USER_UNKNOWN:
                        DEBUG(0, ("smb_pam_account: PAM: User \"%s\" is NOT known to account management\n", user));
                        break;
                case PAM_SUCCESS:
                        DEBUG(4, ("smb_pam_account: PAM: Account OK for User: %s\n", user));
                        break;
                default:
                        DEBUG(0, ("smb_pam_account: PAM: UNKNOWN PAM ERROR (%d) during Account Management for User: %s\n", pam_error, user));
                        break;
        }

        smb_pam_nt_status_error_handler(pamh, pam_error, "Account Check Failed", 2, &nt_status);
        return nt_status;
}

/*
 * PAM Credential Setting
 */

static NTSTATUS smb_pam_setcred(pam_handle_t *pamh, const char * user)
{
        int pam_error;
        NTSTATUS nt_status = NT_STATUS_NO_TOKEN;

        /*
         * This will allow samba to aquire a kerberos token. And, when
         * exporting an AFS cell, be able to /write/ to this cell.
         */

        DEBUG(4,("PAM: Account Management SetCredentials for User: %s\n", user));
        pam_error = pam_setcred(pamh, (PAM_ESTABLISH_CRED|PAM_SILENT)); 
        switch( pam_error ) {
                case PAM_CRED_UNAVAIL:
                        DEBUG(0, ("smb_pam_setcred: PAM: Credentials not found for user:%s\n", user ));
                        break;
                case PAM_CRED_EXPIRED:
                        DEBUG(0, ("smb_pam_setcred: PAM: Credentials for user: \"%s\" EXPIRED!\n", user ));
                        break;
                case PAM_USER_UNKNOWN:
                        DEBUG(0, ("smb_pam_setcred: PAM: User: \"%s\" is NOT known so can not set credentials!\n", user ));
                        break;
                case PAM_CRED_ERR:
                        DEBUG(0, ("smb_pam_setcred: PAM: Unknown setcredentials error - unable to set credentials for %s\n", user ));
                        break;
                case PAM_SUCCESS:
                        DEBUG(4, ("smb_pam_setcred: PAM: SetCredentials OK for User: %s\n", user));
                        break;
                default:
                        DEBUG(0, ("smb_pam_setcred: PAM: UNKNOWN PAM ERROR (%d) during SetCredentials for User: %s\n", pam_error, user));
                        break;
        }

        smb_pam_nt_status_error_handler(pamh, pam_error, "Set Credential Failure", 2, &nt_status);
        return nt_status;
}

/*
 * PAM Internal Session Handler
 */
static BOOL smb_internal_pam_session(pam_handle_t *pamh, const char *user, const char *tty, BOOL flag)
{
        int pam_error;

#ifdef PAM_TTY
        DEBUG(4,("smb_internal_pam_session: PAM: tty set to: %s\n", tty));
        pam_error = pam_set_item(pamh, PAM_TTY, tty);
        if (!smb_pam_error_handler(pamh, pam_error, "set tty failed", 0))
                return False;
#endif

        if (flag) {
                pam_error = pam_open_session(pamh, PAM_SILENT);
                if (!smb_pam_error_handler(pamh, pam_error, "session setup failed", 0))
                        return False;
        } else {
                pam_setcred(pamh, (PAM_DELETE_CRED|PAM_SILENT)); /* We don't care if this fails */
                pam_error = pam_close_session(pamh, PAM_SILENT); /* This will probably pick up the error anyway */
                if (!smb_pam_error_handler(pamh, pam_error, "session close failed", 0))
                        return False;
        }
        return (True);
}

/*
 * Internal PAM Password Changer.
 */

static BOOL smb_pam_chauthtok(pam_handle_t *pamh, const char * user)
{
        int pam_error;

        DEBUG(4,("smb_pam_chauthtok: PAM: Password Change for User: %s\n", user));

        pam_error = pam_chauthtok(pamh, PAM_SILENT); /* Change Password */

        switch( pam_error ) {
        case PAM_AUTHTOK_ERR:
                DEBUG(2, ("PAM: unable to obtain the new authentication token - is password to weak?\n"));
                break;

        /* This doesn't seem to be defined on Solaris. JRA */
#ifdef PAM_AUTHTOK_RECOVER_ERR
        case PAM_AUTHTOK_RECOVER_ERR:
                DEBUG(2, ("PAM: unable to obtain the old authentication token - was the old password wrong?.\n"));
                break;
#endif

        case PAM_AUTHTOK_LOCK_BUSY:
                DEBUG(2, ("PAM: unable to change the authentication token since it is currently locked.\n"));
                break;
        case PAM_AUTHTOK_DISABLE_AGING:
                DEBUG(2, ("PAM: Authentication token aging has been disabled.\n"));
                break;
        case PAM_PERM_DENIED:
                DEBUG(0, ("PAM: Permission denied.\n"));
                break;
        case PAM_TRY_AGAIN:
                DEBUG(0, ("PAM: Could not update all authentication token(s). No authentication tokens were updated.\n"));
                break;
        case PAM_USER_UNKNOWN:
                DEBUG(0, ("PAM: User not known to PAM\n"));
                break;
        case PAM_SUCCESS:
                DEBUG(4, ("PAM: Account OK for User: %s\n", user));
                break;
        default:
                DEBUG(0, ("PAM: UNKNOWN PAM ERROR (%d) for User: %s\n", pam_error, user));
        }
 
        if(!smb_pam_error_handler(pamh, pam_error, "Password Change Failed", 2)) {
                return False;
        }

        /* If this point is reached, the password has changed. */
        return True;
}

/*
 * PAM Externally accessible Session handler
 */

BOOL smb_pam_claim_session(char *user, char *tty, char *rhost)
{
        pam_handle_t *pamh = NULL;
        struct pam_conv *pconv = NULL;

        /* Ignore PAM if told to. */

        if (!lp_obey_pam_restrictions())
                return True;

        if ((pconv = smb_setup_pam_conv(smb_pam_conv, user, NULL, NULL)) == NULL)
                return False;

        if (!smb_pam_start(&pamh, user, rhost, pconv))
                return False;

        if (!smb_internal_pam_session(pamh, user, tty, True)) {
                smb_pam_end(pamh, pconv);
                return False;
        }

        return smb_pam_end(pamh, pconv);
}

/*
 * PAM Externally accessible Session handler
 */

BOOL smb_pam_close_session(char *user, char *tty, char *rhost)
{
        pam_handle_t *pamh = NULL;
        struct pam_conv *pconv = NULL;

        /* Ignore PAM if told to. */

        if (!lp_obey_pam_restrictions())
                return True;

        if ((pconv = smb_setup_pam_conv(smb_pam_conv, user, NULL, NULL)) == NULL)
                return False;

        if (!smb_pam_start(&pamh, user, rhost, pconv))
                return False;

        if (!smb_internal_pam_session(pamh, user, tty, False)) {
                smb_pam_end(pamh, pconv);
                return False;
        }

        return smb_pam_end(pamh, pconv);
}

/*
 * PAM Externally accessible Account handler
 */

NTSTATUS smb_pam_accountcheck(const char * user)
{
        NTSTATUS nt_status = NT_STATUS_ACCOUNT_DISABLED;
        pam_handle_t *pamh = NULL;
        struct pam_conv *pconv = NULL;

        /* Ignore PAM if told to. */

        if (!lp_obey_pam_restrictions())
                return NT_STATUS_OK;

        if ((pconv = smb_setup_pam_conv(smb_pam_conv, user, NULL, NULL)) == NULL)
                return NT_STATUS_NO_MEMORY;

        if (!smb_pam_start(&pamh, user, NULL, pconv))
                return NT_STATUS_ACCOUNT_DISABLED;

        if (!NT_STATUS_IS_OK(nt_status = smb_pam_account(pamh, user)))
                DEBUG(0, ("smb_pam_accountcheck: PAM: Account Validation Failed - Rejecting User %s!\n", user));

        smb_pam_end(pamh, pconv);
        return nt_status;
}

/*
 * PAM Password Validation Suite
 */

NTSTATUS smb_pam_passcheck(const char * user, const char * password)
{
        pam_handle_t *pamh = NULL;
        NTSTATUS nt_status = NT_STATUS_LOGON_FAILURE;
        struct pam_conv *pconv = NULL;

        /*
         * Note we can't ignore PAM here as this is the only
         * way of doing auths on plaintext passwords when
         * compiled --with-pam.
         */

        if ((pconv = smb_setup_pam_conv(smb_pam_conv, user, password, NULL)) == NULL)
                return NT_STATUS_LOGON_FAILURE;

        if (!smb_pam_start(&pamh, user, NULL, pconv))
                return NT_STATUS_LOGON_FAILURE;

        if (!NT_STATUS_IS_OK(nt_status = smb_pam_auth(pamh, user))) {
                DEBUG(0, ("smb_pam_passcheck: PAM: smb_pam_auth failed - Rejecting User %s !\n", user));
                smb_pam_end(pamh, pconv);
                return nt_status;
        }

        if (!NT_STATUS_IS_OK(nt_status = smb_pam_account(pamh, user))) {
                DEBUG(0, ("smb_pam_passcheck: PAM: smb_pam_account failed - Rejecting User %s !\n", user));
                smb_pam_end(pamh, pconv);
                return nt_status;
        }

        if (!NT_STATUS_IS_OK(nt_status = smb_pam_setcred(pamh, user))) {
                DEBUG(0, ("smb_pam_passcheck: PAM: smb_pam_setcred failed - Rejecting User %s !\n", user));
                smb_pam_end(pamh, pconv);
                return nt_status;
        }

        smb_pam_end(pamh, pconv);
        return nt_status;
}

/*
 * PAM Password Change Suite
 */

BOOL smb_pam_passchange(const char * user, const char * oldpassword, const char * newpassword)
{
        /* Appropriate quantities of root should be obtained BEFORE calling this function */
        struct pam_conv *pconv = NULL;
        pam_handle_t *pamh = NULL;

        if ((pconv = smb_setup_pam_conv(smb_pam_passchange_conv, user, oldpassword, newpassword)) == NULL)
                return False;

        if(!smb_pam_start(&pamh, user, NULL, pconv))
                return False;

        if (!smb_pam_chauthtok(pamh, user)) {
                DEBUG(0, ("smb_pam_passchange: PAM: Password Change Failed for user %s!\n", user));
                smb_pam_end(pamh, pconv);
                return False;
        }

        return smb_pam_end(pamh, pconv);
}

#else

/* If PAM not used, no PAM restrictions on accounts. */
NTSTATUS smb_pam_accountcheck(const char * user)
{
        return NT_STATUS_OK;
}

/* If PAM not used, also no PAM restrictions on sessions. */
BOOL smb_pam_claim_session(char *user, char *tty, char *rhost)
{
        return True;
}

/* If PAM not used, also no PAM restrictions on sessions. */
BOOL smb_pam_close_session(char *in_user, char *tty, char *rhost)
{
        return True;
}
#endif /* WITH_PAM */

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