samba-mirror/source3/smbd/chgpasswd.c

/* 
   Unix SMB/CIFS implementation.
   Samba utility functions
   Copyright (C) Andrew Tridgell 1992-1998
   Copyright (C) Andrew Bartlett 2001-2002
   
   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.
*/

/* fork a child process to exec passwd and write to its
 * tty to change a users password. This is running as the
 * user who is attempting to change the password.
 */

/* 
 * This code was copied/borrowed and stolen from various sources.
 * The primary source was the poppasswd.c from the authors of POPMail. This software
 * was included as a client to change passwords using the 'passwd' program
 * on the remote machine.
 *
 * This routine is called by set_user_password() in password.c only if ALLOW_PASSWORD_CHANGE
 * is defined in the compiler directives located in the Makefile.
 *
 * This code has been hacked by Bob Nance (nance@niehs.nih.gov) and Evan Patterson
 * (patters2@niehs.nih.gov) at the National Institute of Environmental Health Sciences
 * and rights to modify, distribute or incorporate this change to the CAP suite or
 * using it for any other reason are granted, so long as this disclaimer is left intact.
 */

/*
   This code was hacked considerably for inclusion in Samba, primarily
   by Andrew.Tridgell@anu.edu.au. The biggest change was the addition
   of the "password chat" option, which allows the easy runtime
   specification of the expected sequence of events to change a
   password.
   */

#include "includes.h"

extern struct passdb_ops pdb_ops;

static NTSTATUS check_oem_password(const char *user,
			       uchar * lmdata, const uchar * lmhash,
			       const uchar * ntdata, const uchar * nthash,
			       SAM_ACCOUNT **hnd, char *new_passwd,
			       int new_passwd_size);

#if ALLOW_CHANGE_PASSWORD

static int findpty(char **slave)
{
	int master;
	static fstring line;
	DIR *dirp;
	const char *dpname;

#if defined(HAVE_GRANTPT)
	/* Try to open /dev/ptmx. If that fails, fall through to old method. */
	if ((master = sys_open("/dev/ptmx", O_RDWR, 0)) >= 0)
	{
		grantpt(master);
		unlockpt(master);
		*slave = (char *)ptsname(master);
		if (*slave == NULL)
		{
			DEBUG(0,
			      ("findpty: Unable to create master/slave pty pair.\n"));
			/* Stop fd leak on error. */
			close(master);
			return -1;
		}
		else
		{
			DEBUG(10,
			      ("findpty: Allocated slave pty %s\n", *slave));
			return (master);
		}
	}
#endif /* HAVE_GRANTPT */

	fstrcpy(line, "/dev/ptyXX");

	dirp = opendir("/dev");
	if (!dirp)
		return (-1);
	while ((dpname = readdirname(dirp)) != NULL)
	{
		if (strncmp(dpname, "pty", 3) == 0 && strlen(dpname) == 5)
		{
			DEBUG(3,
			      ("pty: try to open %s, line was %s\n", dpname,
			       line));
			line[8] = dpname[3];
			line[9] = dpname[4];
			if ((master = sys_open(line, O_RDWR, 0)) >= 0)
			{
				DEBUG(3, ("pty: opened %s\n", line));
				line[5] = 't';
				*slave = line;
				closedir(dirp);
				return (master);
			}
		}
	}
	closedir(dirp);
	return (-1);
}

static int dochild(int master, const char *slavedev, const struct passwd *pass,
		   const char *passwordprogram, BOOL as_root)
{
	int slave;
	struct termios stermios;
	gid_t gid;
	uid_t uid;

	if (pass == NULL)
	{
		DEBUG(0,
		      ("dochild: user doesn't exist in the UNIX password database.\n"));
		return False;
	}

	gid = pass->pw_gid;
	uid = pass->pw_uid;

	gain_root_privilege();

	/* Start new session - gets rid of controlling terminal. */
	if (setsid() < 0)
	{
		DEBUG(3,
		      ("Weirdness, couldn't let go of controlling terminal\n"));
		return (False);
	}

	/* Open slave pty and acquire as new controlling terminal. */
	if ((slave = sys_open(slavedev, O_RDWR, 0)) < 0)
	{
		DEBUG(3, ("More weirdness, could not open %s\n", slavedev));
		return (False);
	}
#ifdef I_PUSH
	ioctl(slave, I_PUSH, "ptem");
	ioctl(slave, I_PUSH, "ldterm");
#elif defined(TIOCSCTTY)
	if (ioctl(slave, TIOCSCTTY, 0) < 0)
	{
		DEBUG(3, ("Error in ioctl call for slave pty\n"));
		/* return(False); */
	}
#endif

	/* Close master. */
	close(master);

	/* Make slave stdin/out/err of child. */

	if (sys_dup2(slave, STDIN_FILENO) != STDIN_FILENO)
	{
		DEBUG(3, ("Could not re-direct stdin\n"));
		return (False);
	}
	if (sys_dup2(slave, STDOUT_FILENO) != STDOUT_FILENO)
	{
		DEBUG(3, ("Could not re-direct stdout\n"));
		return (False);
	}
	if (sys_dup2(slave, STDERR_FILENO) != STDERR_FILENO)
	{
		DEBUG(3, ("Could not re-direct stderr\n"));
		return (False);
	}
	if (slave > 2)
		close(slave);

	/* Set proper terminal attributes - no echo, canonical input processing,
	   no map NL to CR/NL on output. */

	if (tcgetattr(0, &stermios) < 0)
	{
		DEBUG(3,
		      ("could not read default terminal attributes on pty\n"));
		return (False);
	}
	stermios.c_lflag &= ~(ECHO | ECHOE | ECHOK | ECHONL);
	stermios.c_lflag |= ICANON;
#ifdef ONLCR
 	stermios.c_oflag &= ~(ONLCR);
#endif
	if (tcsetattr(0, TCSANOW, &stermios) < 0)
	{
		DEBUG(3, ("could not set attributes of pty\n"));
		return (False);
	}

	/* make us completely into the right uid */
	if (!as_root)
	{
		become_user_permanently(uid, gid);
	}

	DEBUG(10,
	      ("Invoking '%s' as password change program.\n",
	       passwordprogram));

	/* execl() password-change application */
	if (execl("/bin/sh", "sh", "-c", passwordprogram, NULL) < 0)
	{
		DEBUG(3, ("Bad status returned from %s\n", passwordprogram));
		return (False);
	}
	return (True);
}

static int expect(int master, char *issue, char *expected)
{
	pstring buffer;
	int attempts, timeout, nread, len;
	BOOL match = False;

	for (attempts = 0; attempts < 2; attempts++) {
		if (!strequal(issue, ".")) {
			if (lp_passwd_chat_debug())
				DEBUG(100, ("expect: sending [%s]\n", issue));

			if ((len = write(master, issue, strlen(issue))) != strlen(issue)) {
				DEBUG(2,("expect: (short) write returned %d\n", len ));
				return False;
			}
		}

		if (strequal(expected, "."))
			return True;

		timeout = 2000;
		nread = 0;
		buffer[nread] = 0;

		while ((len = read_socket_with_timeout(master, buffer + nread, 1,
						       sizeof(buffer) - nread - 1,
						       timeout)) > 0) {
			nread += len;
			buffer[nread] = 0;

			{
				/* Eat leading/trailing whitespace before match. */
				pstring str;
				pstrcpy( str, buffer);
				trim_string( str, " ", " ");

				if ((match = (unix_wild_match(expected, str) == 0)))
					timeout = 200;
			}
		}

		if (lp_passwd_chat_debug())
			DEBUG(100, ("expect: expected [%s] received [%s] match %s\n",
				    expected, buffer, match ? "yes" : "no" ));

		if (match)
			break;

		if (len < 0) {
			DEBUG(2, ("expect: %s\n", strerror(errno)));
			return False;
		}
	}

	DEBUG(10,("expect: returning %s\n", match ? "True" : "False" ));
	return match;
}

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

static int talktochild(int master, const char *seq)
{
	int count = 0;
	fstring issue, expected;

	fstrcpy(issue, ".");

	while (next_token(&seq, expected, NULL, sizeof(expected)))
	{
		pwd_sub(expected);
		count++;

		if (!expect(master, issue, expected))
		{
			DEBUG(3, ("Response %d incorrect\n", count));
			return False;
		}

		if (!next_token(&seq, issue, NULL, sizeof(issue)))
			fstrcpy(issue, ".");

		pwd_sub(issue);
	}
	if (!strequal(issue, ".")) {
		/* we have one final issue to send */
		fstrcpy(expected, ".");
		if (!expect(master, issue, expected))
			return False;
	}

	return (count > 0);
}

static BOOL chat_with_program(char *passwordprogram, struct passwd *pass,
			      char *chatsequence, BOOL as_root)
{
	char *slavedev;
	int master;
	pid_t pid, wpid;
	int wstat;
	BOOL chstat = False;

	if (pass == NULL)
	{
		DEBUG(0,
		      ("chat_with_program: user doesn't exist in the UNIX password database.\n"));
		return False;
	}

	/* allocate a pseudo-terminal device */
	if ((master = findpty(&slavedev)) < 0)
	{
		DEBUG(3,
		      ("Cannot Allocate pty for password change: %s\n",
		       pass->pw_name));
		return (False);
	}

	/*
	 * We need to temporarily stop CatchChild from eating
	 * SIGCLD signals as it also eats the exit status code. JRA.
	 */

	CatchChildLeaveStatus();

	if ((pid = sys_fork()) < 0)
	{
		DEBUG(3,
		      ("Cannot fork() child for password change: %s\n",
		       pass->pw_name));
		close(master);
		CatchChild();
		return (False);
	}

	/* we now have a pty */
	if (pid > 0)
	{			/* This is the parent process */
		if ((chstat = talktochild(master, chatsequence)) == False)
		{
			DEBUG(3,
			      ("Child failed to change password: %s\n",
			       pass->pw_name));
			kill(pid, SIGKILL);	/* be sure to end this process */
		}

		while ((wpid = sys_waitpid(pid, &wstat, 0)) < 0)
		{
			if (errno == EINTR)
			{
				errno = 0;
				continue;
			}
			break;
		}

		if (wpid < 0)
		{
			DEBUG(3, ("The process is no longer waiting!\n\n"));
			close(master);
			CatchChild();
			return (False);
		}

		/*
		 * Go back to ignoring children.
		 */
		CatchChild();

		close(master);

		if (pid != wpid)
		{
			DEBUG(3,
			      ("We were waiting for the wrong process ID\n"));
			return (False);
		}
		if (WIFEXITED(wstat) == 0)
		{
			DEBUG(3,
			      ("The process exited while we were waiting\n"));
			return (False);
		}
		if (WEXITSTATUS(wstat) != 0)
		{
			DEBUG(3,
			      ("The status of the process exiting was %d\n",
			       wstat));
			return (False);
		}

	}
	else
	{
		/* CHILD */

		/*
		 * Lose any oplock capabilities.
		 */
		oplock_set_capability(False, False);

		/* make sure it doesn't freeze */
		alarm(20);

		if (as_root)
			become_root();

		DEBUG(3,
		      ("Dochild for user %s (uid=%d,gid=%d)\n", pass->pw_name,
		       (int)getuid(), (int)getgid()));
		chstat =
			dochild(master, slavedev, pass, passwordprogram,
				as_root);

		if (as_root)
			unbecome_root();

		/*
		 * The child should never return from dochild() ....
		 */

		DEBUG(0,
		      ("chat_with_program: Error: dochild() returned %d\n",
		       chstat));
		exit(1);
	}

	if (chstat)
		DEBUG(3,
		      ("Password change %ssuccessful for user %s\n",
		       (chstat ? "" : "un"), pass->pw_name));
	return (chstat);
}


BOOL chgpasswd(const char *name, const char *oldpass, const char *newpass, BOOL as_root)
{
	pstring passwordprogram;
	pstring chatsequence;
	size_t i;
	size_t len;

	struct passwd *pass;

	if (!name) {
		DEBUG(1, ("NULL username specfied to chgpasswd()!\n"));
	}
	
	pass = Get_Pwnam(name);
	if (!pass) {
		DEBUG(1, ("Username does not exist in system passwd!\n"));
		return False;
	}

	if (!oldpass) {
		oldpass = "";
	}

	DEBUG(3, ("Password change for user: %s\n", name));

#if DEBUG_PASSWORD
	DEBUG(100, ("Passwords: old=%s new=%s\n", oldpass, newpass));
#endif

	/* Take the passed information and test it for minimum criteria */
	/* Minimum password length */
	if (strlen(newpass) < lp_min_passwd_length()) {
		/* too short, must be at least MINPASSWDLENGTH */
		DEBUG(0, ("Password Change: user %s, New password is shorter than minimum password length = %d\n",
		       name, lp_min_passwd_length()));
		return (False);	/* inform the user */
	}

	/* Password is same as old password */
	if (strcmp(oldpass, newpass) == 0) {
		/* don't allow same password */
		DEBUG(2, ("Password Change: %s, New password is same as old\n", name));	/* log the attempt */
		return (False);	/* inform the user */
	}

	/* 
	 * Check the old and new passwords don't contain any control
	 * characters.
	 */

	len = strlen(oldpass);
	for (i = 0; i < len; i++) {
		if (iscntrl((int)oldpass[i])) {
			DEBUG(0,
			      ("chat_with_program: oldpass contains control characters (disallowed).\n"));
			return False;
		}
	}

	len = strlen(newpass);
	for (i = 0; i < len; i++) {
		if (iscntrl((int)newpass[i])) {
			DEBUG(0,
			      ("chat_with_program: newpass contains control characters (disallowed).\n"));
			return False;
		}
	}
	
#ifdef WITH_PAM
	if (lp_pam_password_change()) {
		BOOL ret;

		if (as_root)
			become_root();

		if (pass) {
			ret = smb_pam_passchange(pass->pw_name, oldpass, newpass);
		} else {
			ret = smb_pam_passchange(name, oldpass, newpass);
		}
			
		if (as_root)
			unbecome_root();

		return ret;
	}
#endif

	/* A non-PAM password change just doen't make sense without a valid local user */

	if (pass == NULL)
	{
		DEBUG(0,
		      ("chgpasswd: user %s doesn't exist in the UNIX password database.\n",
		       name));
		return False;
	}

	pstrcpy(passwordprogram, lp_passwd_program());
	pstrcpy(chatsequence, lp_passwd_chat());

	if (!*chatsequence) {
		DEBUG(2, ("chgpasswd: Null chat sequence - no password changing\n"));
		return (False);
	}

	if (!*passwordprogram) {
		DEBUG(2, ("chgpasswd: Null password program - no password changing\n"));
		return (False);
	}

	if (as_root) {
		/* The password program *must* contain the user name to work. Fail if not. */
		if (strstr(passwordprogram, "%u") == NULL) {
			DEBUG(0,("chgpasswd: Running as root the 'passwd program' parameter *MUST* contain \
the string %%u, and the given string %s does not.\n", passwordprogram ));
			return False;
		}
	}

	pstring_sub(passwordprogram, "%u", name);
	/* note that we do NOT substitute the %o and %n in the password program
	   as this would open up a security hole where the user could use
	   a new password containing shell escape characters */

	pstring_sub(chatsequence, "%u", name);
	all_string_sub(chatsequence, "%o", oldpass, sizeof(pstring));
	all_string_sub(chatsequence, "%n", newpass, sizeof(pstring));
	return (chat_with_program
		(passwordprogram, pass, chatsequence, as_root));
}

#else /* ALLOW_CHANGE_PASSWORD */

BOOL chgpasswd(const char *name, const char *oldpass, const char *newpass, BOOL as_root)
{
	DEBUG(0, ("Password changing not compiled in (user=%s)\n", name));
	return (False);
}
#endif /* ALLOW_CHANGE_PASSWORD */

/***********************************************************
 Code to check the lanman hashed password.
************************************************************/

BOOL check_lanman_password(char *user, uchar * pass1,
			   uchar * pass2, SAM_ACCOUNT **hnd)
{
	uchar unenc_new_pw[16];
	uchar unenc_old_pw[16];
	SAM_ACCOUNT *sampass = NULL;
	uint16 acct_ctrl;
	const uint8 *lanman_pw;
	BOOL ret;
	
	become_root();
	ret = pdb_getsampwnam(sampass, user);
	unbecome_root();

	if (ret == False) {
		DEBUG(0,("check_lanman_password: getsampwnam returned NULL\n"));
		pdb_free_sam(&sampass);
		return False;
	}
	
	acct_ctrl = pdb_get_acct_ctrl     (sampass);
	lanman_pw = pdb_get_lanman_passwd (sampass);

	if (acct_ctrl & ACB_DISABLED) {
		DEBUG(0,("check_lanman_password: account %s disabled.\n", user));
		pdb_free_sam(&sampass);
		return False;
	}

	if (lanman_pw == NULL) {
		if (acct_ctrl & ACB_PWNOTREQ) {
			/* this saves the pointer for the caller */
			*hnd = sampass;
			return True;
		} else {
			DEBUG(0, ("check_lanman_password: no lanman password !\n"));
			pdb_free_sam(&sampass);
			return False;
		}
	}

	/* Get the new lanman hash. */
	D_P16(lanman_pw, pass2, unenc_new_pw);

	/* Use this to get the old lanman hash. */
	D_P16(unenc_new_pw, pass1, unenc_old_pw);

	/* Check that the two old passwords match. */
	if (memcmp(lanman_pw, unenc_old_pw, 16)) {
		DEBUG(0,("check_lanman_password: old password doesn't match.\n"));
		pdb_free_sam(&sampass);
		return False;
	}

	/* this saves the pointer for the caller */
	*hnd = sampass;
	return True;
}

/***********************************************************
 Code to change the lanman hashed password.
 It nulls out the NT hashed password as it will
 no longer be valid.
************************************************************/

BOOL change_lanman_password(SAM_ACCOUNT *sampass, uchar *pass2)
{
	static uchar null_pw[16];
	uchar unenc_new_pw[16];
	BOOL ret;
	uint16 acct_ctrl;
	const uint8 *pwd;

	if (sampass == NULL) {
		DEBUG(0,("change_lanman_password: no smb password entry.\n"));
		return False;
	}
	
	acct_ctrl = pdb_get_acct_ctrl(sampass);
	pwd = pdb_get_lanman_passwd(sampass);

	if (acct_ctrl & ACB_DISABLED) {
		DEBUG(0,("change_lanman_password: account %s disabled.\n",
		       pdb_get_username(sampass)));
		return False;
	}

	if (pwd == NULL) { 
		if (acct_ctrl & ACB_PWNOTREQ) {
			uchar no_pw[14];
			memset(no_pw, '\0', 14);
			E_P16(no_pw, null_pw);

			/* Get the new lanman hash. */
			D_P16(null_pw, pass2, unenc_new_pw);
		} else {
			DEBUG(0,("change_lanman_password: no lanman password !\n"));
			return False;
		}
	} else {
		/* Get the new lanman hash. */
		D_P16(pwd, pass2, unenc_new_pw);
	}

	if (!pdb_set_lanman_passwd(sampass, unenc_new_pw, PDB_CHANGED)) {
		return False;
	}

	if (!pdb_set_nt_passwd    (sampass, NULL, PDB_CHANGED)) {
		return False;	/* We lose the NT hash. Sorry. */
	}

	if (!pdb_set_pass_changed_now  (sampass)) {
		pdb_free_sam(&sampass);
		/* Not quite sure what this one qualifies as, but this will do */
		return False; 
	}
 
	/* Now flush the sam_passwd struct to persistent storage */
	become_root();
	ret = pdb_update_sam_account (sampass);
	unbecome_root();

	return ret;
}

/***********************************************************
 Code to check and change the OEM hashed password.
************************************************************/
NTSTATUS pass_oem_change(char *user,
			 uchar * lmdata, uchar * lmhash,
			 uchar * ntdata, uchar * nthash)
{
	fstring new_passwd;
	const char *unix_user;
	SAM_ACCOUNT *sampass = NULL;
	NTSTATUS nt_status 
		= check_oem_password(user, lmdata, lmhash, ntdata, nthash,
				     &sampass, new_passwd, sizeof(new_passwd));

	if (!NT_STATUS_IS_OK(nt_status))
		return nt_status;

	/* 
	 * At this point we have the new case-sensitive plaintext
	 * password in the fstring new_passwd. If we wanted to synchronise
	 * with UNIX passwords we would call a UNIX password changing 
	 * function here. However it would have to be done as root
	 * as the plaintext of the old users password is not 
	 * available. JRA.
	 */

	unix_user = pdb_get_username(sampass);

	nt_status = change_oem_password(sampass, NULL, new_passwd);

	memset(new_passwd, 0, sizeof(new_passwd));

	pdb_free_sam(&sampass);

	return nt_status;
}

/***********************************************************
 Code to check the OEM hashed password.

 this function ignores the 516 byte nt OEM hashed password
 but does use the lm OEM password to check the nt hashed-hash.

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

static NTSTATUS check_oem_password(const char *user,
			       uchar * lmdata, const uchar * lmhash,
			       const uchar * ntdata, const uchar * nthash,
			       SAM_ACCOUNT **hnd, char *new_passwd,
			       int new_passwd_size)
{
	static uchar null_pw[16];
	static uchar null_ntpw[16];
	SAM_ACCOUNT *sampass = NULL;
	const uint8 *lanman_pw, *nt_pw;
	uint16 acct_ctrl;
	int new_pw_len;
	uchar new_ntp16[16];
	uchar unenc_old_ntpw[16];
	uchar new_p16[16];
	uchar unenc_old_pw[16];
	char no_pw[2];
	BOOL ret;

	BOOL nt_pass_set = (ntdata != NULL && nthash != NULL);

	*hnd = NULL;

	pdb_init_sam(&sampass);

	become_root();
	ret = pdb_getsampwnam(sampass, user);
	unbecome_root();

	if (ret == False) {
		DEBUG(0, ("check_oem_password: getsmbpwnam returned NULL\n"));
		pdb_free_sam(&sampass);
		return NT_STATUS_WRONG_PASSWORD;
		/*
		  TODO: check what Win2k returns for this:
		  return NT_STATUS_NO_SUCH_USER; 
		*/
	}

	acct_ctrl = pdb_get_acct_ctrl(sampass);
	
	if (acct_ctrl & ACB_DISABLED) {
		DEBUG(0,("check_lanman_password: account %s disabled.\n", user));
		pdb_free_sam(&sampass);
		return NT_STATUS_ACCOUNT_DISABLED;
	}

	/* construct a null password (in case one is needed */
	no_pw[0] = 0;
	no_pw[1] = 0;
	nt_lm_owf_gen(no_pw, null_ntpw, null_pw);

	/* save pointers to passwords so we don't have to keep looking them up */
	lanman_pw = pdb_get_lanman_passwd(sampass);
	nt_pw = pdb_get_nt_passwd(sampass);

	/* check for null passwords */
	if (lanman_pw == NULL) {
		if (!(acct_ctrl & ACB_PWNOTREQ)) {
			DEBUG(0,("check_oem_password: no lanman password !\n"));
			pdb_free_sam(&sampass);
			return NT_STATUS_WRONG_PASSWORD;
		}
	}
	
	if (pdb_get_nt_passwd(sampass) == NULL && nt_pass_set) {
		if (!(acct_ctrl & ACB_PWNOTREQ)) {
			DEBUG(0,("check_oem_password: no ntlm password !\n"));
			pdb_free_sam(&sampass);
			return NT_STATUS_WRONG_PASSWORD;
		}
	}
	
	/* 
	 * Call the hash function to get the new password.
	 */
	SamOEMhash( lmdata, lanman_pw, 516);

	/* 
	 * The length of the new password is in the last 4 bytes of
	 * the data buffer.
	 */

	new_pw_len = IVAL(lmdata, 512);

	if (new_pw_len < 0 || new_pw_len > new_passwd_size - 1) {
		DEBUG(0,("check_oem_password: incorrect password length (%d).\n", new_pw_len));
		pdb_free_sam(&sampass);
		return NT_STATUS_WRONG_PASSWORD;
	}

	if (nt_pass_set) {
		/*
		 * nt passwords are in unicode
		 */
		pull_ucs2(NULL, new_passwd, 
			  (const smb_ucs2_t *)&lmdata[512 - new_pw_len],
			  new_passwd_size, new_pw_len, 0);
	} else {
		memcpy(new_passwd, &lmdata[512 - new_pw_len], new_pw_len);
		new_passwd[new_pw_len] = 0;
	}

	/*
	 * To ensure we got the correct new password, hash it and
	 * use it as a key to test the passed old password.
	 */

	nt_lm_owf_gen(new_passwd, new_ntp16, new_p16);

	if (!nt_pass_set) {
		/*
		 * Now use new_p16 as the key to see if the old
		 * password matches.
		 */
		D_P16(new_p16, lmhash, unenc_old_pw);

		if (memcmp(lanman_pw, unenc_old_pw, 16)) {
			DEBUG(0,("check_oem_password: old lm password doesn't match.\n"));
			pdb_free_sam(&sampass);
			return NT_STATUS_WRONG_PASSWORD;
		}

#ifdef DEBUG_PASSWORD
		DEBUG(100,
		      ("check_oem_password: password %s ok\n", new_passwd));
#endif
		*hnd = sampass;
		return NT_STATUS_OK;
	}

	/*
	 * Now use new_p16 as the key to see if the old
	 * password matches.
	 */
	D_P16(new_ntp16, lmhash, unenc_old_pw);
	D_P16(new_ntp16, nthash, unenc_old_ntpw);

	if (memcmp(lanman_pw, unenc_old_pw, 16)) {
		DEBUG(0,("check_oem_password: old lm password doesn't match.\n"));
		pdb_free_sam(&sampass);
		return NT_STATUS_WRONG_PASSWORD;
	}

	if (memcmp(nt_pw, unenc_old_ntpw, 16)) {
		DEBUG(0,("check_oem_password: old nt password doesn't match.\n"));
		pdb_free_sam(&sampass);
		return NT_STATUS_WRONG_PASSWORD;
	}
#ifdef DEBUG_PASSWORD
	DEBUG(100, ("check_oem_password: password %s ok\n", new_passwd));
#endif

	*hnd = sampass;
	return NT_STATUS_OK;
}

/***********************************************************
 Code to change the oem password. Changes both the lanman
 and NT hashes.  Old_passwd is almost always NULL.
************************************************************/

NTSTATUS change_oem_password(SAM_ACCOUNT *hnd, char *old_passwd, char *new_passwd)
{
	BOOL ret;
	uint32 min_len;

	if (time(NULL) < pdb_get_pass_can_change_time(hnd)) {
		DEBUG(1, ("user %s cannot change password now, must wait until %s\n", 
			  pdb_get_username(hnd), http_timestring(pdb_get_pass_can_change_time(hnd))));
		return NT_STATUS_PASSWORD_RESTRICTION;
	}

	if (account_policy_get(AP_MIN_PASSWORD_LEN, &min_len) && (strlen(new_passwd) < min_len)) {
		DEBUG(1, ("user %s cannot change password - password too short\n", 
			  pdb_get_username(hnd)));
		DEBUGADD(1, (" account policy min password len = %d\n", min_len));
		return NT_STATUS_PASSWORD_RESTRICTION;
/* 		return NT_STATUS_PWD_TOO_SHORT; */
	}

	/* Take the passed information and test it for minimum criteria */
	/* Minimum password length */
	if (strlen(new_passwd) < lp_min_passwd_length()) {
		/* too short, must be at least MINPASSWDLENGTH */
		DEBUG(1, ("Password Change: user %s, New password is shorter than minimum password length = %d\n",
		       pdb_get_username(hnd), lp_min_passwd_length()));
		return NT_STATUS_PASSWORD_RESTRICTION;
/* 		return NT_STATUS_PWD_TOO_SHORT; */
	}

	/* TODO:  Add cracklib support here */

	/*
	 * If unix password sync was requested, attempt to change
	 * the /etc/passwd database first. Return failure if this cannot
	 * be done.
	 *
	 * This occurs before the oem change, becouse we don't want to
	 * update it if chgpasswd failed.
	 *
	 * Conditional on lp_unix_password_sync() becouse we don't want
	 * to touch the unix db unless we have admin permission.
	 */
	
	if(lp_unix_password_sync() &&
		!chgpasswd(pdb_get_username(hnd), old_passwd, new_passwd, False)) {
		return NT_STATUS_ACCESS_DENIED;
	}

	if (!pdb_set_plaintext_passwd (hnd, new_passwd)) {
		return NT_STATUS_ACCESS_DENIED;
	}

	/* Now write it into the file. */
	become_root();
	ret = pdb_update_sam_account (hnd);
	unbecome_root();

	if (!ret) {
		return NT_STATUS_ACCESS_DENIED;
	}
	
	return NT_STATUS_OK;
}