r2331: check password script code and example from trunk
[sfrench/samba-autobuild/.git] / source3 / smbd / chgpasswd.c
index 0009f09028dc303029e6555ef517d62be257cef7..7d3ffedec0e04c1120c0c00cedfacd555b66e129 100644 (file)
@@ -2,7 +2,7 @@
    Unix SMB/CIFS implementation.
    Samba utility functions
    Copyright (C) Andrew Tridgell 1992-1998
-   Copyright (C) Andrew Bartlett 2001-2002
+   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
@@ -19,6 +19,8 @@
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
 
+/* 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.
@@ -30,9 +32,6 @@
  * 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
 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);
+                                  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],
+                                  SAM_ACCOUNT **hnd, char *new_passwd,
+                                  int new_passwd_size);
 
 #if ALLOW_CHANGE_PASSWORD
 
@@ -245,7 +246,8 @@ static int expect(int master, char *issue, char *expected)
                if (strequal(expected, "."))
                        return True;
 
-               timeout = 2000;
+               /* Initial timeout. */
+               timeout = lp_passwd_chat_timeout() * 1000;
                nread = 0;
                buffer[nread] = 0;
 
@@ -259,10 +261,12 @@ static int expect(int master, char *issue, char *expected)
                                /* Eat leading/trailing whitespace before match. */
                                pstring str;
                                pstrcpy( str, buffer);
-                               trim_string( str, " ", " ");
+                               trim_char( str, ' ', ' ');
 
-                               if ((match = (unix_wild_match(expected, str) == 0)))
-                                       timeout = 200;
+                               if ((match = (unix_wild_match(expected, str) == 0))) {
+                                       /* Now data has started to return, lower timeout. */
+                                       timeout = lp_passwd_chat_timeout() * 100;
+                               }
                        }
                }
 
@@ -324,7 +328,7 @@ static int talktochild(int master, const char *seq)
        return (count > 0);
 }
 
-static BOOL chat_with_program(char *passwordprogram, struct passwd *pass,
+static BOOL chat_with_program(char *passwordprogram, const struct passwd *pass,
                              char *chatsequence, BOOL as_root)
 {
        char *slavedev;
@@ -340,7 +344,7 @@ static BOOL chat_with_program(char *passwordprogram, struct passwd *pass,
 
        /* allocate a pseudo-terminal device */
        if ((master = findpty(&slavedev)) < 0) {
-               DEBUG(3, ("Cannot Allocate pty for password change: %s\n", pass->pw_name));
+               DEBUG(3, ("chat_with_program: Cannot Allocate pty for password change: %s\n", pass->pw_name));
                return (False);
        }
 
@@ -352,7 +356,7 @@ static BOOL chat_with_program(char *passwordprogram, struct passwd *pass,
        CatchChildLeaveStatus();
 
        if ((pid = sys_fork()) < 0) {
-               DEBUG(3, ("Cannot fork() child for password change: %s\n", pass->pw_name));
+               DEBUG(3, ("chat_with_program: Cannot fork() child for password change: %s\n", pass->pw_name));
                close(master);
                CatchChild();
                return (False);
@@ -361,7 +365,7 @@ static BOOL chat_with_program(char *passwordprogram, struct passwd *pass,
        /* 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));
+                       DEBUG(3, ("chat_with_program: Child failed to change password: %s\n", pass->pw_name));
                        kill(pid, SIGKILL);     /* be sure to end this process */
                }
 
@@ -374,7 +378,7 @@ static BOOL chat_with_program(char *passwordprogram, struct passwd *pass,
                }
 
                if (wpid < 0) {
-                       DEBUG(3, ("The process is no longer waiting!\n\n"));
+                       DEBUG(3, ("chat_with_program: The process is no longer waiting!\n\n"));
                        close(master);
                        CatchChild();
                        return (False);
@@ -388,19 +392,21 @@ static BOOL chat_with_program(char *passwordprogram, struct passwd *pass,
                close(master);
 
                if (pid != wpid) {
-                       DEBUG(3, ("We were waiting for the wrong process ID\n"));
+                       DEBUG(3, ("chat_with_program: 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"));
+               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 (WEXITSTATUS(wstat) != 0) {
-                       DEBUG(3, ("The status of the process exiting was %d\n",
-                              wstat));
+#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 */
 
@@ -415,7 +421,7 @@ static BOOL chat_with_program(char *passwordprogram, struct passwd *pass,
                if (as_root)
                        become_root();
 
-               DEBUG(3, ("Dochild for user %s (uid=%d,gid=%d) (as_root = %s)\n", pass->pw_name,
+               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);
 
@@ -431,53 +437,35 @@ static BOOL chat_with_program(char *passwordprogram, struct passwd *pass,
        }
 
        if (chstat)
-               DEBUG(3, ("Password change %ssuccessful for user %s\n",
+               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 *oldpass, const char *newpass, BOOL as_root)
+BOOL chgpasswd(const char *name, const struct passwd *pass, 
+              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 (as_root=%s) for user: %s\n", BOOLSTR(as_root), name));
+       DEBUG(3, ("chgpasswd: Password change (as_root=%s) for user: %s\n", BOOLSTR(as_root), name));
 
 #if DEBUG_PASSWORD
-       DEBUG(100, ("Passwords: old=%s new=%s\n", oldpass, newpass));
+       DEBUG(100, ("chgpasswd: 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 */
+               DEBUG(2, ("chgpasswd: Password Change: %s, New password is same as old\n", name));      /* log the attempt */
                return (False); /* inform the user */
        }
 
@@ -489,7 +477,7 @@ BOOL chgpasswd(const char *name, const char *oldpass, const char *newpass, BOOL
        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"));
+                       DEBUG(0, ("chgpasswd: oldpass contains control characters (disallowed).\n"));
                        return False;
                }
        }
@@ -497,7 +485,7 @@ BOOL chgpasswd(const char *name, const char *oldpass, const char *newpass, BOOL
        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"));
+                       DEBUG(0, ("chgpasswd: newpass contains control characters (disallowed).\n"));
                        return False;
                }
        }
@@ -544,7 +532,7 @@ BOOL chgpasswd(const char *name, const char *oldpass, const char *newpass, BOOL
 
        if (as_root) {
                /* The password program *must* contain the user name to work. Fail if not. */
-               if (strstr(passwordprogram, "%u") == NULL) {
+               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;
@@ -565,9 +553,10 @@ the string %%u, and the given string %s does not.\n", passwordprogram ));
 
 #else /* ALLOW_CHANGE_PASSWORD */
 
-BOOL chgpasswd(const char *name, const char *oldpass, const char *newpass, BOOL as_root)
+BOOL chgpasswd(const char *name, const struct passwd *pass, 
+              const char *oldpass, const char *newpass, BOOL as_root)
 {
-       DEBUG(0, ("Password changing not compiled in (user=%s)\n", name));
+       DEBUG(0, ("chgpasswd: Unix Password changing not compiled in (user=%s)\n", name));
        return (False);
 }
 #endif /* ALLOW_CHANGE_PASSWORD */
@@ -707,14 +696,19 @@ BOOL change_lanman_password(SAM_ACCOUNT *sampass, uchar *pass2)
 ************************************************************/
 
 NTSTATUS pass_oem_change(char *user,
-                        uchar * lmdata, uchar * lmhash,
-                        uchar * ntdata, uchar * nthash)
+                        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])
 {
-       fstring new_passwd;
+       pstring new_passwd;
        SAM_ACCOUNT *sampass = NULL;
-       NTSTATUS nt_status = check_oem_password(user, lmdata, lmhash, ntdata, nthash,
-                                    &sampass, new_passwd, sizeof(new_passwd));
-
+       NTSTATUS 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, sizeof(new_passwd));
+       
        if (!NT_STATUS_IS_OK(nt_status))
                return nt_status;
 
@@ -731,33 +725,42 @@ NTSTATUS pass_oem_change(char *user,
 }
 
 /***********************************************************
- Code to check the OEM hashed password.
+ Decrypt and verify a user password change.  
 
- this function ignores the 516 byte nt OEM hashed password
- but does use the lm OEM password to check the nt hashed-hash.
+ 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 * lmdata, const uchar * lmhash,
-                              const uchar * ntdata, const uchar * nthash,
-                              SAM_ACCOUNT **hnd, char *new_passwd,
-                              int new_passwd_size)
+                                  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],
+                                  SAM_ACCOUNT **hnd, char *new_passwd,
+                                  int new_passwd_size)
 {
        static uchar null_pw[16];
        static uchar null_ntpw[16];
        SAM_ACCOUNT *sampass = NULL;
+       char *password_encrypted;
+       const char *encryption_key;
        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];
+       uint32 new_pw_len;
+       uchar new_nt_hash[16];
+       uchar old_nt_hash_plain[16];
+       uchar new_lm_hash[16];
+       uchar old_lm_hash_plain[16];
        char no_pw[2];
        BOOL ret;
 
-       BOOL nt_pass_set = (ntdata != NULL && nthash != NULL);
+       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);
 
        *hnd = NULL;
 
@@ -770,97 +773,152 @@ static NTSTATUS check_oem_password(const char *user,
        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; 
-               */
+               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));
+               DEBUG(2,("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);
+       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;
 
-       /* 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;
+       } 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 (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;
-               }
+
+       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));
+               pdb_free_sam(&sampass);
+               return NT_STATUS_WRONG_PASSWORD;        
+       } else if (lm_pass_set) {
+               DEBUG(1, ("LM password change supplied for user %s, but we have no LanMan password to check it with\n", 
+                         user));
+               pdb_free_sam(&sampass);
+               return NT_STATUS_WRONG_PASSWORD;
+       } else {
+               DEBUG(1, ("password change requested for user %s, but no password supplied!\n", 
+                         user));
+               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.
+        * Decrypt the password with the key 
         */
+       SamOEMhash( password_encrypted, encryption_key, 516);
 
-       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));
+       if ( !decode_pw_buffer(password_encrypted, new_passwd, new_passwd_size, &new_pw_len, 
+                              nt_pass_set ? STR_UNICODE : STR_ASCII)) {
                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) {
+               /* NT passwords, verify the NT hash. */
+               
+               /* Calculate the MD4 hash (NT compatible) of the password */
+               memset(new_nt_hash, '\0', 16);
+               E_md4hash(new_passwd, new_nt_hash);
+
+               if (nt_pw) {
+                       /*
+                        * Now use new_nt_hash as the key to see if the old
+                        * password matches.
+                        */
+                       D_P16(new_nt_hash, old_nt_hash_encrypted, old_nt_hash_plain);
+                       
+                       if (memcmp(nt_pw, old_nt_hash_plain, 16)) {
+                               DEBUG(0,("check_oem_password: old lm password doesn't match.\n"));
+                               pdb_free_sam(&sampass);
+                               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", new_passwd));
+#endif
+                       *hnd = sampass;
+                       return NT_STATUS_OK;
+               }
+               
+               if (lanman_pw) {
+                       /*
+                        * Now use new_nt_hash as the key to see if the old
+                        * LM password matches.
+                        */
+                       D_P16(new_nt_hash, old_lm_hash_encrypted, old_lm_hash_plain);
+                       
+                       if (memcmp(lanman_pw, old_lm_hash_plain, 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;
+               }
+       }
+
+       if (lanman_pw && lm_pass_set) {
+
+               E_deshash(new_passwd, new_lm_hash);
 
-       if (!nt_pass_set) {
                /*
-                * Now use new_p16 as the key to see if the old
+                * Now use new_lm_hash 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)) {
+               D_P16(new_lm_hash, old_lm_hash_encrypted, old_lm_hash_plain);
+               
+               if (memcmp(lanman_pw, old_lm_hash_plain, 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));
@@ -869,30 +927,74 @@ static NTSTATUS check_oem_password(const char *user,
                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);
+       /* should not be reached */
+       pdb_free_sam(&sampass);
+       return NT_STATUS_WRONG_PASSWORD;
+}
 
-       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;
+/***********************************************************
+ 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(SAM_ACCOUNT *sampass, const char *plaintext)
+{
+       uchar new_nt_p16[NT_HASH_LEN];
+       uchar zero_md5_nt_pw[SALTED_MD5_HASH_LEN];
+       const uint8 *nt_pw;
+       const uint8 *pwhistory;
+       BOOL found = False;
+       int i, pwHisLen, curr_pwHisLen;
+
+       account_policy_get(AP_PASSWORD_HISTORY, &pwHisLen);
+       if (pwHisLen == 0) {
+               return False;
        }
 
-       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;
+       pwhistory = pdb_get_pw_history(sampass, &curr_pwHisLen);
+       if (!pwhistory || curr_pwHisLen == 0) {
+               return False;
        }
-#ifdef DEBUG_PASSWORD
-       DEBUG(100, ("check_oem_password: password %s ok\n", new_passwd));
-#endif
 
-       *hnd = sampass;
-       return NT_STATUS_OK;
+       /* 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;
+       }
+
+       dump_data(100, new_nt_p16, NT_HASH_LEN);
+       dump_data(100, pwhistory, PW_HISTORY_ENTRY_LEN*pwHisLen);
+
+       memset(zero_md5_nt_pw, '\0', SALTED_MD5_HASH_LEN);
+       for (i=0; i<pwHisLen; i++) {
+               uchar new_nt_pw_salted_md5_hash[SALTED_MD5_HASH_LEN];
+               const uchar *current_salt = &pwhistory[i*PW_HISTORY_ENTRY_LEN];
+               const uchar *old_nt_pw_salted_md5_hash = &pwhistory[(i*PW_HISTORY_ENTRY_LEN)+
+                                                       PW_HISTORY_SALT_LEN];
+               if (!memcmp(zero_md5_nt_pw, old_nt_pw_salted_md5_hash, SALTED_MD5_HASH_LEN)) {
+                       /* Ignore zero valued entries. */
+                       continue;
+               }
+               /* Create salted versions of new to compare. */
+               E_md5hash(current_salt, new_nt_p16, new_nt_pw_salted_md5_hash);
+
+               if (!memcmp(new_nt_pw_salted_md5_hash, old_nt_pw_salted_md5_hash, SALTED_MD5_HASH_LEN)) {
+                       DEBUG(1,("check_passwd_history: proposed new password for user %s found in history list !\n",
+                               pdb_get_username(sampass) ));
+                       found = True;
+                       break;
+               }
+       }
+       return found;
 }
 
 /***********************************************************
@@ -906,16 +1008,19 @@ NTSTATUS change_oem_password(SAM_ACCOUNT *hnd, char *old_passwd, char *new_passw
 {
        BOOL ret;
        uint32 min_len;
+       struct passwd *pass = NULL;
+       const char *username = pdb_get_username(hnd);
+       time_t can_change_time = pdb_get_pass_can_change_time(hnd);
 
-       if (time(NULL) < pdb_get_pass_can_change_time(hnd)) {
+       if ((can_change_time != 0) && (time(NULL) < can_change_time)) {
                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;
+                         username, http_timestring(can_change_time)));
+               return NT_STATUS_ACCOUNT_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)));
+                         username));
                DEBUGADD(1, (" account policy min password len = %d\n", min_len));
                return NT_STATUS_PASSWORD_RESTRICTION;
 /*             return NT_STATUS_PWD_TOO_SHORT; */
@@ -926,12 +1031,33 @@ NTSTATUS change_oem_password(SAM_ACCOUNT *hnd, char *old_passwd, char *new_passw
        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()));
+                      username, lp_min_passwd_length()));
                return NT_STATUS_PASSWORD_RESTRICTION;
 /*             return NT_STATUS_PWD_TOO_SHORT; */
        }
 
-       /* TODO:  Add cracklib support here */
+       if (check_passwd_history(hnd,new_passwd)) {
+               return NT_STATUS_PASSWORD_RESTRICTION;
+       }
+
+       pass = Get_Pwnam(username);
+       if (!pass) {
+               DEBUG(1, ("check_oem_password: Username %s does not exist in system !?!\n", username));
+               return NT_STATUS_ACCESS_DENIED;
+       }
+
+       /* Use external script to check password complexity */
+       if (lp_check_password_script()) {
+               int check_ret;
+
+               check_ret = smbrunsecret(lp_check_password_script(), new_passwd);
+               DEBUG(5, ("change_oem_password: check password script (%s) returned [%d]\n", lp_check_password_script(), check_ret));
+
+               if (check_ret != 0) {
+                       DEBUG(1, ("change_oem_password: check password script said new password is not good enough!\n"));
+                       return NT_STATUS_PASSWORD_RESTRICTION;
+               }
+       }
 
        /*
         * If unix password sync was requested, attempt to change
@@ -946,7 +1072,7 @@ NTSTATUS change_oem_password(SAM_ACCOUNT *hnd, char *old_passwd, char *new_passw
         */
        
        if(lp_unix_password_sync() &&
-               !chgpasswd(pdb_get_username(hnd), old_passwd, new_passwd, as_root)) {
+               !chgpasswd(username, pass, old_passwd, new_passwd, as_root)) {
                return NT_STATUS_ACCESS_DENIED;
        }