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|
/*
Unix SMB/CIFS implementation.
Use PAM to update user passwords in the local SAM
Copyright (C) Steve Langasek 1998-2003
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.
*/
/* indicate the following groups are defined */
#define PAM_SM_PASSWORD
#include "includes.h"
/* This is only used in the Sun implementation. FIXME: we really
want a define here that distinguishes between the Solaris PAM
and others (including FreeBSD). */
#ifndef LINUX
#include <security/pam_appl.h>
#endif
#include <security/pam_modules.h>
#include "general.h"
#include "support.h"
int smb_update_db( pam_handle_t *pamh, int ctrl, const char *user, const char *pass_new )
{
int retval;
pstring err_str;
pstring msg_str;
err_str[0] = '\0';
msg_str[0] = '\0';
retval = local_password_change( user, LOCAL_SET_PASSWORD, pass_new,
err_str, sizeof(err_str),
msg_str, sizeof(msg_str) );
if (!retval) {
if (*err_str) {
err_str[PSTRING_LEN-1] = '\0';
make_remark( pamh, ctrl, PAM_ERROR_MSG, err_str );
}
/* FIXME: what value is appropriate here? */
retval = PAM_AUTHTOK_ERR;
} else {
if (*msg_str) {
msg_str[PSTRING_LEN-1] = '\0';
make_remark( pamh, ctrl, PAM_TEXT_INFO, msg_str );
}
retval = PAM_SUCCESS;
}
return retval;
}
/* data tokens */
#define _SMB_OLD_AUTHTOK "-SMB-OLD-PASS"
#define _SMB_NEW_AUTHTOK "-SMB-NEW-PASS"
/*
* FUNCTION: pam_sm_chauthtok()
*
* This function is called twice by the PAM library, once with
* PAM_PRELIM_CHECK set, and then again with PAM_UPDATE_AUTHTOK set. With
* Linux-PAM, these two passes generally involve first checking the old
* token and then changing the token. This is what we do here.
*
* Having obtained a new password. The function updates the
* SMB_PASSWD_FILE file (normally, $(LIBDIR)/smbpasswd).
*/
int pam_sm_chauthtok(pam_handle_t *pamh, int flags,
int argc, const char **argv)
{
unsigned int ctrl;
int retval;
extern BOOL in_client;
SAM_ACCOUNT *sampass = NULL;
void (*oldsig_handler)(int);
const char *user;
char *pass_old;
char *pass_new;
NTSTATUS nt_status;
/* Samba initialization. */
setup_logging( "pam_smbpass", False );
in_client = True;
ctrl = set_ctrl(flags, argc, argv);
/*
* First get the name of a user. No need to do anything if we can't
* determine this.
*/
retval = pam_get_user( pamh, &user, "Username: " );
if (retval != PAM_SUCCESS) {
if (on( SMB_DEBUG, ctrl )) {
_log_err( LOG_DEBUG, "password: could not identify user" );
}
return retval;
}
if (on( SMB_DEBUG, ctrl )) {
_log_err( LOG_DEBUG, "username [%s] obtained", user );
}
/* Getting into places that might use LDAP -- protect the app
from a SIGPIPE it's not expecting */
oldsig_handler = CatchSignal(SIGPIPE, SIGNAL_CAST SIG_IGN);
if (!initialize_password_db(True)) {
_log_err( LOG_ALERT, "Cannot access samba password database" );
CatchSignal(SIGPIPE, SIGNAL_CAST oldsig_handler);
return PAM_AUTHINFO_UNAVAIL;
}
/* obtain user record */
if (!NT_STATUS_IS_OK(nt_status = pdb_init_sam(&sampass))) {
CatchSignal(SIGPIPE, SIGNAL_CAST oldsig_handler);
return nt_status_to_pam(nt_status);
}
if (!pdb_getsampwnam(sampass,user)) {
_log_err( LOG_ALERT, "Failed to find entry for user %s.", user );
CatchSignal(SIGPIPE, SIGNAL_CAST oldsig_handler);
return PAM_USER_UNKNOWN;
}
if (flags & PAM_PRELIM_CHECK) {
/*
* obtain and verify the current password (OLDAUTHTOK) for
* the user.
*/
char *Announce;
if (_smb_blankpasswd( ctrl, sampass )) {
pdb_free_sam(&sampass);
CatchSignal(SIGPIPE, SIGNAL_CAST oldsig_handler);
return PAM_SUCCESS;
}
/* Password change by root, or for an expired token, doesn't
require authentication. Is this a good choice? */
if (getuid() != 0 && !(flags & PAM_CHANGE_EXPIRED_AUTHTOK)) {
/* tell user what is happening */
#define greeting "Changing password for "
Announce = (char *) malloc(sizeof(greeting)+strlen(user));
if (Announce == NULL) {
_log_err(LOG_CRIT, "password: out of memory");
pdb_free_sam(&sampass);
CatchSignal(SIGPIPE, SIGNAL_CAST oldsig_handler);
return PAM_BUF_ERR;
}
strncpy( Announce, greeting, sizeof(greeting) );
strncpy( Announce+sizeof(greeting)-1, user, strlen(user)+1 );
#undef greeting
set( SMB__OLD_PASSWD, ctrl );
retval = _smb_read_password( pamh, ctrl, Announce, "Current SMB password: ",
NULL, _SMB_OLD_AUTHTOK, &pass_old );
SAFE_FREE( Announce );
if (retval != PAM_SUCCESS) {
_log_err( LOG_NOTICE
, "password - (old) token not obtained" );
pdb_free_sam(&sampass);
CatchSignal(SIGPIPE, SIGNAL_CAST oldsig_handler);
return retval;
}
/* verify that this is the password for this user */
retval = _smb_verify_password( pamh, sampass, pass_old, ctrl );
} else {
pass_old = NULL;
retval = PAM_SUCCESS; /* root doesn't have to */
}
pass_old = NULL;
pdb_free_sam(&sampass);
CatchSignal(SIGPIPE, SIGNAL_CAST oldsig_handler);
return retval;
} else if (flags & PAM_UPDATE_AUTHTOK) {
/*
* obtain the proposed password
*/
/*
* get the old token back. NULL was ok only if root [at this
* point we assume that this has already been enforced on a
* previous call to this function].
*/
if (off( SMB_NOT_SET_PASS, ctrl )) {
retval = pam_get_item( pamh, PAM_OLDAUTHTOK,
(const void **)&pass_old );
} else {
retval = pam_get_data( pamh, _SMB_OLD_AUTHTOK,
(const void **)&pass_old );
if (retval == PAM_NO_MODULE_DATA) {
pass_old = NULL;
retval = PAM_SUCCESS;
}
}
if (retval != PAM_SUCCESS) {
_log_err( LOG_NOTICE, "password: user not authenticated" );
pdb_free_sam(&sampass);
CatchSignal(SIGPIPE, SIGNAL_CAST oldsig_handler);
return retval;
}
/*
* use_authtok is to force the use of a previously entered
* password -- needed for pluggable password strength checking
* or other module stacking
*/
if (on( SMB_USE_AUTHTOK, ctrl )) {
set( SMB_USE_FIRST_PASS, ctrl );
}
retval = _smb_read_password( pamh, ctrl
, NULL
, "Enter new SMB password: "
, "Retype new SMB password: "
, _SMB_NEW_AUTHTOK
, &pass_new );
if (retval != PAM_SUCCESS) {
if (on( SMB_DEBUG, ctrl )) {
_log_err( LOG_ALERT
, "password: new password not obtained" );
}
pass_old = NULL; /* tidy up */
pdb_free_sam(&sampass);
CatchSignal(SIGPIPE, SIGNAL_CAST oldsig_handler);
return retval;
}
/*
* At this point we know who the user is and what they
* propose as their new password. Verify that the new
* password is acceptable.
*/
if (pass_new[0] == '\0') { /* "\0" password = NULL */
pass_new = NULL;
}
retval = _pam_smb_approve_pass(pamh, ctrl, pass_old, pass_new);
if (retval != PAM_SUCCESS) {
_log_err(LOG_NOTICE, "new password not acceptable");
pass_new = pass_old = NULL; /* tidy up */
pdb_free_sam(&sampass);
CatchSignal(SIGPIPE, SIGNAL_CAST oldsig_handler);
return retval;
}
/*
* By reaching here we have approved the passwords and must now
* rebuild the smb password file.
*/
/* update the password database */
retval = smb_update_db(pamh, ctrl, user, pass_new);
if (retval == PAM_SUCCESS) {
uid_t uid;
/* password updated */
if (!sid_to_uid(pdb_get_user_sid(sampass), &uid)) {
_log_err( LOG_NOTICE, "Unable to get uid for user %s",
pdb_get_username(sampass));
_log_err( LOG_NOTICE, "password for (%s) changed by (%s/%d)",
user, uidtoname(getuid()), getuid());
} else {
_log_err( LOG_NOTICE, "password for (%s/%d) changed by (%s/%d)",
user, uid, uidtoname(getuid()), getuid());
}
} else {
_log_err( LOG_ERR, "password change failed for user %s", user);
}
pass_old = pass_new = NULL;
if (sampass) {
pdb_free_sam(&sampass);
sampass = NULL;
}
} else { /* something has broken with the library */
_log_err( LOG_ALERT, "password received unknown request" );
retval = PAM_ABORT;
}
if (sampass) {
pdb_free_sam(&sampass);
sampass = NULL;
}
pdb_free_sam(&sampass);
CatchSignal(SIGPIPE, SIGNAL_CAST oldsig_handler);
return retval;
}
/* static module data */
#ifdef PAM_STATIC
struct pam_module _pam_smbpass_passwd_modstruct = {
"pam_smbpass",
NULL,
NULL,
NULL,
NULL,
NULL,
pam_sm_chauthtok
};
#endif
|
