This is a nice rewrite:

[Samba.git] / 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;
}