dsdb-acl: give error string if we can not obtain the schema

[Samba/gebeck_regimport.git] / source3 / rpc_server / samr / srv_samr_chgpasswd.c

/*
   Unix SMB/CIFS implementation.
   Samba utility functions
   Copyright (C) Andrew Tridgell 1992-1998
   Copyright (C) Andrew Bartlett 2001-2004

   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 3 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, see <http://www.gnu.org/licenses/>.
*/

/* These comments regard the code to change the user's unix password: */

/* 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 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"
#include "system/terminal.h"
#include "system/passwd.h"
#include "system/filesys.h"
#include "../libcli/auth/libcli_auth.h"
#include "../lib/crypto/arcfour.h"
#include "rpc_server/samr/srv_samr_util.h"
#include "passdb.h"
#include "auth.h"

#ifndef ALLOW_CHANGE_PASSWORD
#if (defined(HAVE_TERMIOS_H) && defined(HAVE_DUP2) && defined(HAVE_SETSID))
#define ALLOW_CHANGE_PASSWORD 1
#endif
#endif

#if ALLOW_CHANGE_PASSWORD

static int findpty(char **slave)
{
        int master = -1;
        char *line = NULL;
        DIR *dirp = NULL;
        const char *dpname;

        *slave = NULL;

#if defined(HAVE_GRANTPT)
        /* Try to open /dev/ptmx. If that fails, fall through to old method. */
        if ((master = open("/dev/ptmx", O_RDWR, 0)) >= 0) {
                grantpt(master);
                unlockpt(master);
                line = (char *)ptsname(master);
                if (line) {
                        *slave = SMB_STRDUP(line);
                }

                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 */

        line = SMB_STRDUP("/dev/ptyXX");
        if (!line) {
                return (-1);
        }

        dirp = opendir("/dev");
        if (!dirp) {
                SAFE_FREE(line);
                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 = open(line, O_RDWR, 0)) >= 0) {
                                DEBUG(3, ("pty: opened %s\n", line));
                                line[5] = 't';
                                *slave = line;
                                closedir(dirp);
                                return (master);
                        }
                }
        }
        closedir(dirp);
        SAFE_FREE(line);
        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;
        char * const eptrs[1] = { NULL };

        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 = open(slavedev, O_RDWR, 0)) < 0)
        {
                DEBUG(3, ("More weirdness, could not open %s\n", slavedev));
                return (False);
        }
#if defined(TIOCSCTTY) && !defined(SUNOS5)
        /*
         * On patched Solaris 10 TIOCSCTTY is defined but seems not to work,
         * see the discussion under
         * https://bugzilla.samba.org/show_bug.cgi?id=5366.
         */
        if (ioctl(slave, TIOCSCTTY, 0) < 0)
        {
                DEBUG(3, ("Error in ioctl call for slave pty\n"));
                /* return(False); */
        }
#elif defined(I_PUSH) && defined(I_FIND)
        if (ioctl(slave, I_FIND, "ptem") == 0) {
                ioctl(slave, I_PUSH, "ptem");
        }
        if (ioctl(slave, I_FIND, "ldterm") == 0) {
                ioctl(slave, I_PUSH, "ldterm");
        }
#endif

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

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

        if (dup2(slave, STDIN_FILENO) != STDIN_FILENO)
        {
                DEBUG(3, ("Could not re-direct stdin\n"));
                return (False);
        }
        if (dup2(slave, STDOUT_FILENO) != STDOUT_FILENO)
        {
                DEBUG(3, ("Could not re-direct stdout\n"));
                return (False);
        }
        if (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 (execle("/bin/sh", "sh", "-c", passwordprogram, NULL, eptrs) < 0)
        {
                DEBUG(3, ("Bad status returned from %s\n", passwordprogram));
                return (False);
        }
        return (True);
}

static int expect(int master, char *issue, char *expected)
{
        char buffer[1024];
        int attempts, timeout, nread;
        size_t len;
        bool match = False;

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

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

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

                /* Initial timeout. */
                timeout = lp_passwd_chat_timeout() * 1000;
                nread = 0;
                buffer[nread] = 0;

                while (True) {
                        status = read_fd_with_timeout(
                                master, buffer + nread, 1,
                                sizeof(buffer) - nread - 1,
                                timeout, &len);

                        if (!NT_STATUS_IS_OK(status)) {
                                DEBUG(2, ("expect: read error %s\n",
                                          nt_errstr(status)));
                                break;
                        }
                        nread += len;
                        buffer[nread] = 0;

                        {
                                /* Eat leading/trailing whitespace before match. */
                                char *str = SMB_STRDUP(buffer);
                                if (!str) {
                                        DEBUG(2,("expect: ENOMEM\n"));
                                        return False;
                                }
                                trim_char(str, ' ', ' ');

                                if ((match = unix_wild_match(expected, str)) == True) {
                                        /* Now data has started to return, lower timeout. */
                                        timeout = lp_passwd_chat_timeout() * 100;
                                }
                                SAFE_FREE(str);
                        }
                }

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

                if (match)
                        break;

                if (!NT_STATUS_IS_OK(status)) {
                        DEBUG(2, ("expect: %s\n", nt_errstr(status)));
                        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)
{
        TALLOC_CTX *frame = talloc_stackframe();
        int count = 0;
        char *issue;
        char *expected;

        issue = talloc_strdup(frame, ".");
        if (!issue) {
                TALLOC_FREE(frame);
                return false;
        }

        while (next_token_talloc(frame, &seq, &expected, NULL)) {
                pwd_sub(expected);
                count++;

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

                if (!next_token_talloc(frame, &seq, &issue, NULL)) {
                        issue = talloc_strdup(frame, ".");
                        if (!issue) {
                                TALLOC_FREE(frame);
                                return false;
                        }
                }
                pwd_sub(issue);
        }

        if (!strequal(issue, ".")) {
                /* we have one final issue to send */
                expected = talloc_strdup(frame, ".");
                if (!expected) {
                        TALLOC_FREE(frame);
                        return false;
                }
                if (!expect(master, issue, expected)) {
                        TALLOC_FREE(frame);
                        return False;
                }
        }
        TALLOC_FREE(frame);
        return (count > 0);
}

static bool chat_with_program(char *passwordprogram, const struct passwd *pass,
                              char *chatsequence, bool as_root)
{
        char *slavedev = NULL;
        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, ("chat_with_program: 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 = fork()) < 0) {
                DEBUG(3, ("chat_with_program: Cannot fork() child for password change: %s\n", pass->pw_name));
                SAFE_FREE(slavedev);
                close(master);
                CatchChild();
                return (False);
        }

        /* we now have a pty */
        if (pid > 0) {                  /* This is the parent process */
                /* Don't need this anymore in parent. */
                SAFE_FREE(slavedev);

                if ((chstat = talktochild(master, chatsequence)) == False) {
                        DEBUG(3, ("chat_with_program: 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, ("chat_with_program: 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, ("chat_with_program: We were waiting for the wrong process ID\n"));
                        return (False);
                }
                if (WIFEXITED(wstat) && (WEXITSTATUS(wstat) != 0)) {
                        DEBUG(3, ("chat_with_program: The process exited with status %d \
while we were waiting\n", WEXITSTATUS(wstat)));
                        return (False);
                }
#if defined(WIFSIGNALLED) && defined(WTERMSIG)
                else if (WIFSIGNALLED(wstat)) {
                        DEBUG(3, ("chat_with_program: The process was killed by signal %d \
while we were waiting\n", WTERMSIG(wstat)));
                        return (False);
                }
#endif
        } else {
                /* CHILD */

                /*
                 * Lose any elevated privileges.
                 */
                drop_effective_capability(KERNEL_OPLOCK_CAPABILITY);
                drop_effective_capability(DMAPI_ACCESS_CAPABILITY);

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

                if (as_root)
                        become_root();

                DEBUG(3, ("chat_with_program: Dochild for user %s (uid=%d,gid=%d) (as_root = %s)\n", pass->pw_name,
                       (int)getuid(), (int)getgid(), BOOLSTR(as_root) ));
                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, ("chat_with_program: Password change %ssuccessful for user %s\n",
                       (chstat ? "" : "un"), pass->pw_name));
        return (chstat);
}

bool chgpasswd(const char *name, const char *rhost, const struct passwd *pass,
               const char *oldpass, const char *newpass, bool as_root)
{
        char *passwordprogram = NULL;
        char *chatsequence = NULL;
        size_t i;
        size_t len;
        TALLOC_CTX *ctx = talloc_tos();

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

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

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

        /* Take the passed information and test it for minimum criteria */

        /* Password is same as old password */
        if (strcmp(oldpass, newpass) == 0) {
                /* don't allow same password */
                DEBUG(2, ("chgpasswd: 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, ("chgpasswd: oldpass contains control characters (disallowed).\n"));
                        return False;
                }
        }

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

#ifdef WITH_PAM
        if (lp_pam_password_change()) {
                bool ret;
#ifdef HAVE_SETLOCALE
                const char *prevlocale = setlocale(LC_ALL, "C");
#endif

                if (as_root)
                        become_root();

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

                if (as_root)
                        unbecome_root();

#ifdef HAVE_SETLOCALE
                setlocale(LC_ALL, prevlocale);
#endif

                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;
        }

        passwordprogram = lp_passwd_program(ctx);
        if (!passwordprogram || !*passwordprogram) {
                DEBUG(2, ("chgpasswd: Null password program - no password changing\n"));
                return false;
        }
        chatsequence = lp_passwd_chat(ctx);
        if (!chatsequence || !*chatsequence) {
                DEBUG(2, ("chgpasswd: Null chat sequence - no password changing\n"));
                return false;
        }

        if (as_root) {
                /* The password program *must* contain the user name to work. Fail if not. */
                if (strstr_m(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;
                }
        }

        passwordprogram = talloc_string_sub(ctx, passwordprogram, "%u", name);
        if (!passwordprogram) {
                return false;
        }

        /* 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 */

        chatsequence = talloc_string_sub(ctx, chatsequence, "%u", name);
        if (!chatsequence) {
                return false;
        }
        chatsequence = talloc_all_string_sub(ctx,
                                        chatsequence,
                                        "%o",
                                        oldpass);
        if (!chatsequence) {
                return false;
        }
        chatsequence = talloc_all_string_sub(ctx,
                                        chatsequence,
                                        "%n",
                                        newpass);
        return chat_with_program(passwordprogram,
                                pass,
                                chatsequence,
                                as_root);
}

#else /* ALLOW_CHANGE_PASSWORD */

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

/***********************************************************
 Decrypt and verify a user password change.

 The 516 byte long buffers are encrypted with the old NT and
 old LM passwords, and if the NT passwords are present, both
 buffers contain a unicode string.

 After decrypting the buffers, check the password is correct by
 matching the old hashed passwords with the passwords in the passdb.

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

static NTSTATUS check_oem_password(const char *user,
                                   uchar password_encrypted_with_lm_hash[516],
                                   const uchar old_lm_hash_encrypted[16],
                                   uchar password_encrypted_with_nt_hash[516],
                                   const uchar old_nt_hash_encrypted[16],
                                   struct samu *sampass,
                                   char **pp_new_passwd)
{
        uchar null_pw[16];
        uchar null_ntpw[16];
        uint8 *password_encrypted;
        const uint8 *encryption_key;
        const uint8 *lanman_pw, *nt_pw;
        uint32 acct_ctrl;
        size_t new_pw_len;
        uchar new_nt_hash[16];
        uchar new_lm_hash[16];
        uchar verifier[16];
        char no_pw[2];

        bool nt_pass_set = (password_encrypted_with_nt_hash && old_nt_hash_encrypted);
        bool lm_pass_set = (password_encrypted_with_lm_hash && old_lm_hash_encrypted);

        acct_ctrl = pdb_get_acct_ctrl(sampass);
#if 0
        /* I am convinced this check here is wrong, it is valid to
         * change a password of a user that has a disabled account - gd */

        if (acct_ctrl & ACB_DISABLED) {
                DEBUG(2,("check_lanman_password: account %s disabled.\n", user));
                return NT_STATUS_ACCOUNT_DISABLED;
        }
#endif
        if ((acct_ctrl & ACB_PWNOTREQ) && lp_null_passwords()) {
                /* 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);
                lanman_pw = null_pw;
                nt_pw = null_pw;

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

        if (nt_pw && nt_pass_set) {
                /* IDEAL Case: passwords are in unicode, and we can
                 * read use the password encrypted with the NT hash
                 */
                password_encrypted = password_encrypted_with_nt_hash;
                encryption_key = nt_pw;
        } else if (lanman_pw && lm_pass_set) {
                /* password may still be in unicode, but use LM hash version */
                password_encrypted = password_encrypted_with_lm_hash;
                encryption_key = lanman_pw;
        } else if (nt_pass_set) {
                DEBUG(1, ("NT password change supplied for user %s, but we have no NT password to check it with\n",
                          user));
                return NT_STATUS_WRONG_PASSWORD;
        } else if (lm_pass_set) {
                if (lp_lanman_auth()) {
                        DEBUG(1, ("LM password change supplied for user %s, but we have no LanMan password to check it with\n",
                                  user));
                } else {
                        DEBUG(1, ("LM password change supplied for user %s, but we have disabled LanMan authentication\n",
                                  user));
                }
                return NT_STATUS_WRONG_PASSWORD;
        } else {
                DEBUG(1, ("password change requested for user %s, but no password supplied!\n",
                          user));
                return NT_STATUS_WRONG_PASSWORD;
        }

        /*
         * Decrypt the password with the key
         */
        arcfour_crypt( password_encrypted, encryption_key, 516);

        if (!decode_pw_buffer(talloc_tos(),
                                password_encrypted,
                                pp_new_passwd,
                                &new_pw_len,
                                nt_pass_set ? CH_UTF16 : CH_DOS)) {
                return NT_STATUS_WRONG_PASSWORD;
        }

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

        if (nt_pass_set) {
                /* NT passwords, verify the NT hash. */

                /* Calculate the MD4 hash (NT compatible) of the password */
                memset(new_nt_hash, '\0', 16);
                E_md4hash(*pp_new_passwd, new_nt_hash);

                if (nt_pw) {
                        /*
                         * check the NT verifier
                         */
                        E_old_pw_hash(new_nt_hash, nt_pw, verifier);
                        if (memcmp(verifier, old_nt_hash_encrypted, 16)) {
                                DEBUG(0, ("check_oem_password: old nt "
                                          "password doesn't match.\n"));
                                return NT_STATUS_WRONG_PASSWORD;
                        }

                        /* We could check the LM password here, but there is
                         * little point, we already know the password is
                         * correct, and the LM password might not even be
                         * present. */

                        /* Further, LM hash generation algorithms
                         * differ with charset, so we could
                         * incorrectly fail a perfectly valid password
                         * change */
#ifdef DEBUG_PASSWORD
                        DEBUG(100,
                              ("check_oem_password: password %s ok\n", *pp_new_passwd));
#endif
                        return NT_STATUS_OK;
                }

                if (lanman_pw) {
                        /*
                         * check the lm verifier
                         */
                        E_old_pw_hash(new_nt_hash, lanman_pw, verifier);
                        if (memcmp(verifier, old_lm_hash_encrypted, 16)) {
                                DEBUG(0,("check_oem_password: old lm password doesn't match.\n"));
                                return NT_STATUS_WRONG_PASSWORD;
                        }
#ifdef DEBUG_PASSWORD
                        DEBUG(100,
                              ("check_oem_password: password %s ok\n", *pp_new_passwd));
#endif
                        return NT_STATUS_OK;
                }
        }

        if (lanman_pw && lm_pass_set) {

                E_deshash(*pp_new_passwd, new_lm_hash);

                /*
                 * check the lm verifier
                 */
                E_old_pw_hash(new_lm_hash, lanman_pw, verifier);
                if (memcmp(verifier, old_lm_hash_encrypted, 16)) {
                        DEBUG(0,("check_oem_password: old lm password doesn't match.\n"));
                        return NT_STATUS_WRONG_PASSWORD;
                }

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

        /* should not be reached */
        return NT_STATUS_WRONG_PASSWORD;
}

static bool password_in_history(uint8_t nt_pw[NT_HASH_LEN],
                                uint32_t pw_history_len,
                                const uint8_t *pw_history)
{
        static const uint8_t zero_md5_nt_pw[SALTED_MD5_HASH_LEN] = { 0, };
        int i;

        dump_data(100, nt_pw, NT_HASH_LEN);
        dump_data(100, pw_history, PW_HISTORY_ENTRY_LEN * pw_history_len);

        for (i=0; i<pw_history_len; i++) {
                uint8_t new_nt_pw_salted_md5_hash[SALTED_MD5_HASH_LEN];
                const uint8_t *current_salt;
                const uint8_t *old_nt_pw_salted_md5_hash;

                current_salt = &pw_history[i*PW_HISTORY_ENTRY_LEN];
                old_nt_pw_salted_md5_hash = current_salt + PW_HISTORY_SALT_LEN;

                if (memcmp(zero_md5_nt_pw, old_nt_pw_salted_md5_hash,
                           SALTED_MD5_HASH_LEN) == 0) {
                        /* Ignore zero valued entries. */
                        continue;
                }

                if (memcmp(zero_md5_nt_pw, current_salt,
                           PW_HISTORY_SALT_LEN) == 0)
                {
                        /*
                         * New format: zero salt and then plain nt hash.
                         * Directly compare the hashes.
                         */
                        if (memcmp(nt_pw, old_nt_pw_salted_md5_hash,
                                   SALTED_MD5_HASH_LEN) == 0)
                        {
                                return true;
                        }
                } else {
                        /*
                         * Old format: md5sum of salted nt hash.
                         * Create salted version of new pw to compare.
                         */
                        E_md5hash(current_salt, nt_pw, new_nt_pw_salted_md5_hash);

                        if (memcmp(new_nt_pw_salted_md5_hash,
                                   old_nt_pw_salted_md5_hash,
                                   SALTED_MD5_HASH_LEN) == 0) {
                                return true;
                        }
                }
        }
        return false;
}

/***********************************************************
 This routine takes the given password and checks it against
 the password history. Returns True if this password has been
 found in the history list.
************************************************************/

static bool check_passwd_history(struct samu *sampass, const char *plaintext)
{
        uchar new_nt_p16[NT_HASH_LEN];
        const uint8 *nt_pw;
        const uint8 *pwhistory;
        uint32 pwHisLen, curr_pwHisLen;

        pdb_get_account_policy(PDB_POLICY_PASSWORD_HISTORY, &pwHisLen);
        if (pwHisLen == 0) {
                return False;
        }

        pwhistory = pdb_get_pw_history(sampass, &curr_pwHisLen);
        if (!pwhistory || curr_pwHisLen == 0) {
                return False;
        }

        /* Only examine the minimum of the current history len and
           the stored history len. Avoids race conditions. */
        pwHisLen = MIN(pwHisLen,curr_pwHisLen);

        nt_pw = pdb_get_nt_passwd(sampass);

        E_md4hash(plaintext, new_nt_p16);

        if (!memcmp(nt_pw, new_nt_p16, NT_HASH_LEN)) {
                DEBUG(10,("check_passwd_history: proposed new password for user %s is the same as the current password !\n",
                        pdb_get_username(sampass) ));
                return True;
        }

        if (password_in_history(new_nt_p16, pwHisLen, pwhistory)) {
                DEBUG(1,("check_passwd_history: proposed new password for "
                         "user %s found in history list !\n",
                         pdb_get_username(sampass) ));
                return true;
        }
        return false;
}

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

NTSTATUS check_password_complexity(const char *username,
                                   const char *password,
                                   enum samPwdChangeReason *samr_reject_reason)
{
        TALLOC_CTX *tosctx = talloc_tos();
        int check_ret;
        char *cmd;

        /* Use external script to check password complexity */
        if ((lp_check_password_script(tosctx) == NULL)
            || (*(lp_check_password_script(tosctx)) == '\0')) {
                return NT_STATUS_OK;
        }

        cmd = talloc_string_sub(tosctx, lp_check_password_script(tosctx), "%u",
                                username);
        if (!cmd) {
                return NT_STATUS_PASSWORD_RESTRICTION;
        }

        check_ret = smbrunsecret(cmd, password);
        DEBUG(5,("check_password_complexity: check password script (%s) "
                 "returned [%d]\n", cmd, check_ret));
        TALLOC_FREE(cmd);

        if (check_ret != 0) {
                DEBUG(1,("check_password_complexity: "
                         "check password script said new password is not good "
                         "enough!\n"));
                if (samr_reject_reason) {
                        *samr_reject_reason = SAM_PWD_CHANGE_NOT_COMPLEX;
                }
                return NT_STATUS_PASSWORD_RESTRICTION;
        }

        return NT_STATUS_OK;
}

/***********************************************************
 Code to change the oem password. Changes both the lanman
 and NT hashes.  Old_passwd is almost always NULL.
 NOTE this function is designed to be called as root. Check the old password
 is correct before calling. JRA.
************************************************************/

static NTSTATUS change_oem_password(struct samu *hnd, const char *rhost,
                                    char *old_passwd, char *new_passwd,
                                    bool as_root,
                                    enum samPwdChangeReason *samr_reject_reason)
{
        uint32 min_len;
        uint32 refuse;
        TALLOC_CTX *tosctx = talloc_tos();
        struct passwd *pass = NULL;
        const char *username = pdb_get_username(hnd);
        time_t can_change_time = pdb_get_pass_can_change_time(hnd);
        NTSTATUS status;

        if (samr_reject_reason) {
                *samr_reject_reason = SAM_PWD_CHANGE_NO_ERROR;
        }

        /* check to see if the secdesc has previously been set to disallow */
        if (!pdb_get_pass_can_change(hnd)) {
                DEBUG(1, ("user %s does not have permissions to change password\n", username));
                if (samr_reject_reason) {
                        *samr_reject_reason = SAM_PWD_CHANGE_NO_ERROR;
                }
                return NT_STATUS_ACCOUNT_RESTRICTION;
        }

        /* check to see if it is a Machine account and if the policy
         * denies machines to change the password. *
         * Should we deny also SRVTRUST and/or DOMSTRUST ? .SSS. */
        if (pdb_get_acct_ctrl(hnd) & ACB_WSTRUST) {
                if (pdb_get_account_policy(PDB_POLICY_REFUSE_MACHINE_PW_CHANGE, &refuse) && refuse) {
                        DEBUG(1, ("Machine %s cannot change password now, "
                                  "denied by Refuse Machine Password Change policy\n",
                                  username));
                        if (samr_reject_reason) {
                                *samr_reject_reason = SAM_PWD_CHANGE_NO_ERROR;
                        }
                        return NT_STATUS_ACCOUNT_RESTRICTION;
                }
        }

        /* removed calculation here, because passdb now calculates
           based on policy.  jmcd */
        if ((can_change_time != 0) && (time(NULL) < can_change_time)) {
                DEBUG(1, ("user %s cannot change password now, must "
                          "wait until %s\n", username,
                          http_timestring(tosctx, can_change_time)));
                if (samr_reject_reason) {
                        *samr_reject_reason = SAM_PWD_CHANGE_NO_ERROR;
                }
                return NT_STATUS_ACCOUNT_RESTRICTION;
        }

        if (pdb_get_account_policy(PDB_POLICY_MIN_PASSWORD_LEN, &min_len) && (str_charnum(new_passwd) < min_len)) {
                DEBUG(1, ("user %s cannot change password - password too short\n",
                          username));
                DEBUGADD(1, (" account policy min password len = %d\n", min_len));
                if (samr_reject_reason) {
                        *samr_reject_reason = SAM_PWD_CHANGE_PASSWORD_TOO_SHORT;
                }
                return NT_STATUS_PASSWORD_RESTRICTION;
/*              return NT_STATUS_PWD_TOO_SHORT; */
        }

        if (check_passwd_history(hnd,new_passwd)) {
                if (samr_reject_reason) {
                        *samr_reject_reason = SAM_PWD_CHANGE_PWD_IN_HISTORY;
                }
                return NT_STATUS_PASSWORD_RESTRICTION;
        }

        pass = Get_Pwnam_alloc(tosctx, username);
        if (!pass) {
                DEBUG(1, ("change_oem_password: Username %s does not exist in system !?!\n", username));
                return NT_STATUS_ACCESS_DENIED;
        }

        status = check_password_complexity(username, new_passwd, samr_reject_reason);
        if (!NT_STATUS_IS_OK(status)) {
                TALLOC_FREE(pass);
                return status;
        }

        /*
         * 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, because we don't want to
         * update it if chgpasswd failed.
         *
         * Conditional on lp_unix_password_sync() because we don't want
         * to touch the unix db unless we have admin permission.
         */

        if(lp_unix_password_sync() &&
           !chgpasswd(username, rhost, pass, old_passwd, new_passwd,
                      as_root)) {
                TALLOC_FREE(pass);
                return NT_STATUS_ACCESS_DENIED;
        }

        TALLOC_FREE(pass);

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

        /* Now write it into the file. */
        return pdb_update_sam_account (hnd);
}

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

NTSTATUS pass_oem_change(char *user, const char *rhost,
                         uchar password_encrypted_with_lm_hash[516],
                         const uchar old_lm_hash_encrypted[16],
                         uchar password_encrypted_with_nt_hash[516],
                         const uchar old_nt_hash_encrypted[16],
                         enum samPwdChangeReason *reject_reason)
{
        char *new_passwd = NULL;
        struct samu *sampass = NULL;
        NTSTATUS nt_status;
        bool ret = false;

        if (!(sampass = samu_new(NULL))) {
                return NT_STATUS_NO_MEMORY;
        }

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

        if (ret == false) {
                DEBUG(0,("pass_oem_change: getsmbpwnam returned NULL\n"));
                TALLOC_FREE(sampass);
                return NT_STATUS_NO_SUCH_USER;
        }

        nt_status = check_oem_password(user,
                                       password_encrypted_with_lm_hash,
                                       old_lm_hash_encrypted,
                                       password_encrypted_with_nt_hash,
                                       old_nt_hash_encrypted,
                                       sampass,
                                       &new_passwd);

        if (!NT_STATUS_IS_OK(nt_status)) {
                TALLOC_FREE(sampass);
                return nt_status;
        }

        /* We've already checked the old password here.... */
        become_root();
        nt_status = change_oem_password(sampass, rhost, NULL, new_passwd,
                                        True, reject_reason);
        unbecome_root();

        memset(new_passwd, 0, strlen(new_passwd));

        TALLOC_FREE(sampass);

        return nt_status;
}