Initial import
[samba] / source / nsswitch / pam_winbind.c
diff --git a/source/nsswitch/pam_winbind.c b/source/nsswitch/pam_winbind.c
new file mode 100644 (file)
index 0000000..61c01da
--- /dev/null
@@ -0,0 +1,851 @@
+/* pam_winbind module
+
+   Copyright Andrew Tridgell <tridge@samba.org> 2000
+   Copyright Tim Potter <tpot@samba.org> 2000
+   Copyright Andrew Bartlett <abartlet@samba.org> 2002
+
+   largely based on pam_userdb by Cristian Gafton <gafton@redhat.com> 
+   also contains large slabs of code from pam_unix by Elliot Lee <sopwith@redhat.com>
+   (see copyright below for full details)
+*/
+
+#include "pam_winbind.h"
+
+/* data tokens */
+
+#define MAX_PASSWD_TRIES       3
+
+/* some syslogging */
+static void _pam_log(int err, const char *format, ...)
+{
+       va_list args;
+
+       va_start(args, format);
+       openlog(MODULE_NAME, LOG_CONS|LOG_PID, LOG_AUTH);
+       vsyslog(err, format, args);
+       va_end(args);
+       closelog();
+}
+
+static int _pam_parse(int argc, const char **argv)
+{
+       int ctrl;
+       /* step through arguments */
+       for (ctrl = 0; argc-- > 0; ++argv) {
+
+               /* generic options */
+               
+               if (!strcmp(*argv,"debug"))
+                       ctrl |= WINBIND_DEBUG_ARG;
+               else if (!strcasecmp(*argv, "use_authtok"))
+                       ctrl |= WINBIND_USE_AUTHTOK_ARG;
+               else if (!strcasecmp(*argv, "use_first_pass"))
+                       ctrl |= WINBIND_USE_FIRST_PASS_ARG;
+               else if (!strcasecmp(*argv, "try_first_pass"))
+                       ctrl |= WINBIND_TRY_FIRST_PASS_ARG;
+               else if (!strcasecmp(*argv, "unknown_ok"))
+                       ctrl |= WINBIND_UNKNOWN_OK_ARG;
+               else if (!strncasecmp(*argv, "require_membership_of", strlen("require_membership_of")))
+                       ctrl |= WINBIND_REQUIRED_MEMBERSHIP;
+               else if (!strncasecmp(*argv, "require-membership-of", strlen("require-membership-of")))
+                       ctrl |= WINBIND_REQUIRED_MEMBERSHIP;
+               else {
+                       _pam_log(LOG_ERR, "pam_parse: unknown option; %s", *argv);
+               }
+       }
+       
+       return ctrl;
+}
+
+static void _pam_winbind_cleanup_func(pam_handle_t *pamh, void *data, int error_status)
+{
+       SAFE_FREE(data);
+}
+
+/* --- authentication management functions --- */
+
+/* Attempt a conversation */
+
+static int converse(pam_handle_t *pamh, int nargs,
+                   struct pam_message **message,
+                   struct pam_response **response)
+{
+    int retval;
+    struct pam_conv *conv;
+
+    retval = pam_get_item(pamh, PAM_CONV, (const void **) &conv ) ;
+    if (retval == PAM_SUCCESS) {
+       retval = conv->conv(nargs, (const struct pam_message **)message,
+                           response, conv->appdata_ptr);
+    }
+       
+    return retval; /* propagate error status */
+}
+
+
+static int _make_remark(pam_handle_t * pamh, int type, const char *text)
+{
+       int retval = PAM_SUCCESS;
+
+       struct pam_message *pmsg[1], msg[1];
+       struct pam_response *resp;
+       
+       pmsg[0] = &msg[0];
+       msg[0].msg = text;
+       msg[0].msg_style = type;
+       
+       resp = NULL;
+       retval = converse(pamh, 1, pmsg, &resp);
+       
+       if (resp) {
+               _pam_drop_reply(resp, 1);
+       }
+       return retval;
+}
+
+static int pam_winbind_request(enum winbindd_cmd req_type,
+                              struct winbindd_request *request,
+                              struct winbindd_response *response)
+{
+
+       /* Fill in request and send down pipe */
+       init_request(request, req_type);
+       
+       if (write_sock(request, sizeof(*request), 0) == -1) {
+               _pam_log(LOG_ERR, "write to socket failed!");
+               close_sock();
+               return PAM_SERVICE_ERR;
+       }
+       
+       /* Wait for reply */
+       if (read_reply(response) == -1) {
+               _pam_log(LOG_ERR, "read from socket failed!");
+               close_sock();
+               return PAM_SERVICE_ERR;
+       }
+
+       /* We are done with the socket - close it and avoid mischeif */
+       close_sock();
+
+       /* Copy reply data from socket */
+       if (response->result != WINBINDD_OK) {
+               if (response->data.auth.pam_error != PAM_SUCCESS) {
+                       _pam_log(LOG_ERR, "request failed: %s, PAM error was %d, NT error was %s", 
+                                response->data.auth.error_string,
+                                response->data.auth.pam_error,
+                                response->data.auth.nt_status_string);
+                       return response->data.auth.pam_error;
+               } else {
+                       _pam_log(LOG_ERR, "request failed, but PAM error 0!");
+                       return PAM_SERVICE_ERR;
+               }
+       }
+       
+       return PAM_SUCCESS;
+}
+
+static int pam_winbind_request_log(enum winbindd_cmd req_type,
+                              struct winbindd_request *request,
+                              struct winbindd_response *response,
+                                  int ctrl,
+                                  const char *user)
+{
+       int retval;
+
+        retval = pam_winbind_request(req_type, request, response);
+
+       switch (retval) {
+       case PAM_AUTH_ERR:
+               /* incorrect password */
+               _pam_log(LOG_WARNING, "user `%s' denied access (incorrect password or invalid membership)", user);
+               return retval;
+       case PAM_ACCT_EXPIRED:
+               /* account expired */
+               _pam_log(LOG_WARNING, "user `%s' account expired", user);
+               return retval;
+       case PAM_AUTHTOK_EXPIRED:
+               /* password expired */
+               _pam_log(LOG_WARNING, "user `%s' password expired", user);
+               return retval;
+       case PAM_NEW_AUTHTOK_REQD:
+               /* password expired */
+               _pam_log(LOG_WARNING, "user `%s' new password required", user);
+               return retval;
+       case PAM_USER_UNKNOWN:
+               /* the user does not exist */
+               if (ctrl & WINBIND_DEBUG_ARG)
+                       _pam_log(LOG_NOTICE, "user `%s' not found",
+                                user);
+               if (ctrl & WINBIND_UNKNOWN_OK_ARG) {
+                       return PAM_IGNORE;
+               }        
+               return retval;
+       case PAM_SUCCESS:
+               if (req_type == WINBINDD_PAM_AUTH) {
+                       /* Otherwise, the authentication looked good */
+                       _pam_log(LOG_NOTICE, "user '%s' granted access", user);
+               } else if (req_type == WINBINDD_PAM_CHAUTHTOK) {
+                       /* Otherwise, the authentication looked good */
+                       _pam_log(LOG_NOTICE, "user '%s' password changed", user);
+               } else { 
+                       /* Otherwise, the authentication looked good */
+                       _pam_log(LOG_NOTICE, "user '%s' OK", user);
+               }
+               return retval;
+       default:
+               /* we don't know anything about this return value */
+               _pam_log(LOG_ERR, "internal module error (retval = %d, user = `%s')",
+                        retval, user);
+               return retval;
+       }
+}
+
+/* talk to winbindd */
+static int winbind_auth_request(const char *user, const char *pass, const char *member, int ctrl)
+{
+       struct winbindd_request request;
+       struct winbindd_response response;
+
+       ZERO_STRUCT(request);
+
+       strncpy(request.data.auth.user, user, 
+                sizeof(request.data.auth.user)-1);
+
+       strncpy(request.data.auth.pass, pass, 
+                sizeof(request.data.auth.pass)-1);
+
+       if (member == NULL )
+               return pam_winbind_request_log(WINBINDD_PAM_AUTH, &request, &response, ctrl, user);
+
+       /* lookup name? */ 
+       if (!strncmp("S-", member, 2) == 0) {
+               
+               struct winbindd_request sid_request;
+               struct winbindd_response sid_response;
+
+               ZERO_STRUCT(sid_request);
+               ZERO_STRUCT(sid_response);
+
+               if (ctrl & WINBIND_DEBUG_ARG)
+                       _pam_log(LOG_DEBUG, "no sid given, looking up: %s\n", member);
+
+               /* fortunatly winbindd can handle non-separated names */
+               strcpy(sid_request.data.name.name, member);
+
+               if (pam_winbind_request_log(WINBINDD_LOOKUPNAME, &sid_request, &sid_response, ctrl, user)) {
+                       _pam_log(LOG_INFO, "could not lookup name: %s\n", member); 
+                       return PAM_AUTH_ERR;
+               }
+
+               member = sid_response.data.sid.sid;
+       }
+
+       strncpy(request.data.auth.require_membership_of_sid, member, 
+               sizeof(request.data.auth.require_membership_of_sid)-1);
+       
+        return pam_winbind_request_log(WINBINDD_PAM_AUTH, &request, &response, ctrl, user);
+}
+
+/* talk to winbindd */
+static int winbind_chauthtok_request(const char *user, const char *oldpass,
+                                     const char *newpass, int ctrl)
+{
+       struct winbindd_request request;
+       struct winbindd_response response;
+
+       ZERO_STRUCT(request);
+
+        if (request.data.chauthtok.user == NULL) return -2;
+
+       strncpy(request.data.chauthtok.user, user, 
+                sizeof(request.data.chauthtok.user) - 1);
+
+        if (oldpass != NULL) {
+            strncpy(request.data.chauthtok.oldpass, oldpass, 
+                    sizeof(request.data.chauthtok.oldpass) - 1);
+        } else {
+            request.data.chauthtok.oldpass[0] = '\0';
+        }
+       
+        if (newpass != NULL) {
+            strncpy(request.data.chauthtok.newpass, newpass, 
+                    sizeof(request.data.chauthtok.newpass) - 1);
+        } else {
+            request.data.chauthtok.newpass[0] = '\0';
+        }
+       
+        return pam_winbind_request_log(WINBINDD_PAM_CHAUTHTOK, &request, &response, ctrl, user);
+}
+
+/*
+ * Checks if a user has an account
+ *
+ * return values:
+ *      1  = User not found
+ *      0  = OK
+ *     -1  = System error
+ */
+static int valid_user(const char *user)
+{
+       if (getpwnam(user)) return 0;
+       return 1;
+}
+
+static char *_pam_delete(register char *xx)
+{
+    _pam_overwrite(xx);
+    _pam_drop(xx);
+    return NULL;
+}
+
+/*
+ * obtain a password from the user
+ */
+
+static int _winbind_read_password(pam_handle_t * pamh
+                                 ,unsigned int ctrl
+                                 ,const char *comment
+                                 ,const char *prompt1
+                                 ,const char *prompt2
+                                 ,const char **pass)
+{
+       int authtok_flag;
+       int retval;
+       const char *item;
+       char *token;
+
+       /*
+        * make sure nothing inappropriate gets returned
+        */
+
+       *pass = token = NULL;
+
+       /*
+        * which authentication token are we getting?
+        */
+
+       authtok_flag = on(WINBIND__OLD_PASSWORD, ctrl) ? PAM_OLDAUTHTOK : PAM_AUTHTOK;
+
+       /*
+        * should we obtain the password from a PAM item ?
+        */
+
+       if (on(WINBIND_TRY_FIRST_PASS_ARG, ctrl) || on(WINBIND_USE_FIRST_PASS_ARG, ctrl)) {
+               retval = pam_get_item(pamh, authtok_flag, (const void **) &item);
+               if (retval != PAM_SUCCESS) {
+                       /* very strange. */
+                       _pam_log(LOG_ALERT, 
+                                "pam_get_item returned error to unix-read-password"
+                           );
+                       return retval;
+               } else if (item != NULL) {      /* we have a password! */
+                       *pass = item;
+                       item = NULL;
+                       return PAM_SUCCESS;
+               } else if (on(WINBIND_USE_FIRST_PASS_ARG, ctrl)) {
+                       return PAM_AUTHTOK_RECOVER_ERR;         /* didn't work */
+               } else if (on(WINBIND_USE_AUTHTOK_ARG, ctrl)
+                          && off(WINBIND__OLD_PASSWORD, ctrl)) {
+                       return PAM_AUTHTOK_RECOVER_ERR;
+               }
+       }
+       /*
+        * getting here implies we will have to get the password from the
+        * user directly.
+        */
+
+       {
+               struct pam_message msg[3], *pmsg[3];
+               struct pam_response *resp;
+               int i, replies;
+
+               /* prepare to converse */
+
+               if (comment != NULL) {
+                       pmsg[0] = &msg[0];
+                       msg[0].msg_style = PAM_TEXT_INFO;
+                       msg[0].msg = comment;
+                       i = 1;
+               } else {
+                       i = 0;
+               }
+
+               pmsg[i] = &msg[i];
+               msg[i].msg_style = PAM_PROMPT_ECHO_OFF;
+               msg[i++].msg = prompt1;
+               replies = 1;
+
+               if (prompt2 != NULL) {
+                       pmsg[i] = &msg[i];
+                       msg[i].msg_style = PAM_PROMPT_ECHO_OFF;
+                       msg[i++].msg = prompt2;
+                       ++replies;
+               }
+               /* so call the conversation expecting i responses */
+               resp = NULL;
+               retval = converse(pamh, i, pmsg, &resp);
+
+               if (resp != NULL) {
+
+                       /* interpret the response */
+
+                       if (retval == PAM_SUCCESS) {    /* a good conversation */
+
+                               token = x_strdup(resp[i - replies].resp);
+                               if (token != NULL) {
+                                       if (replies == 2) {
+
+                                               /* verify that password entered correctly */
+                                               if (!resp[i - 1].resp
+                                                   || strcmp(token, resp[i - 1].resp)) {
+                                                       _pam_delete(token);     /* mistyped */
+                                                       retval = PAM_AUTHTOK_RECOVER_ERR;
+                                                       _make_remark(pamh                                                                   ,PAM_ERROR_MSG, MISTYPED_PASS);
+                                               }
+                                       }
+                               } else {
+                                       _pam_log(LOG_NOTICE
+                                                ,"could not recover authentication token");
+                               }
+
+                       }
+                       /*
+                        * tidy up the conversation (resp_retcode) is ignored
+                        * -- what is it for anyway? AGM
+                        */
+
+                       _pam_drop_reply(resp, i);
+
+               } else {
+                       retval = (retval == PAM_SUCCESS)
+                           ? PAM_AUTHTOK_RECOVER_ERR : retval;
+               }
+       }
+
+       if (retval != PAM_SUCCESS) {
+               if (on(WINBIND_DEBUG_ARG, ctrl))
+                       _pam_log(LOG_DEBUG,
+                                "unable to obtain a password");
+               return retval;
+       }
+       /* 'token' is the entered password */
+
+       /* we store this password as an item */
+       
+       retval = pam_set_item(pamh, authtok_flag, token);
+       _pam_delete(token);     /* clean it up */
+       if (retval != PAM_SUCCESS
+           || (retval = pam_get_item(pamh, authtok_flag
+                                     ,(const void **) &item))
+           != PAM_SUCCESS) {
+               
+               _pam_log(LOG_CRIT, "error manipulating password");
+               return retval;
+               
+       }
+
+       *pass = item;
+       item = NULL;            /* break link to password */
+
+       return PAM_SUCCESS;
+}
+
+PAM_EXTERN
+int pam_sm_authenticate(pam_handle_t *pamh, int flags,
+                       int argc, const char **argv)
+{
+     const char *username;
+     const char *password;
+     const char *member = NULL;
+     int retval = PAM_AUTH_ERR;
+     int i;
+    
+     /* parse arguments */
+     int ctrl = _pam_parse(argc, argv);
+
+     /* Get the username */
+     retval = pam_get_user(pamh, &username, NULL);
+     if ((retval != PAM_SUCCESS) || (!username)) {
+        if (ctrl & WINBIND_DEBUG_ARG)
+            _pam_log(LOG_DEBUG,"can not get the username");
+        return PAM_SERVICE_ERR;
+     }
+     
+     retval = _winbind_read_password(pamh, ctrl, NULL, 
+                                    "Password: ", NULL,
+                                    &password);
+     
+     if (retval != PAM_SUCCESS) {
+        _pam_log(LOG_ERR, "Could not retrieve user's password");
+        return PAM_AUTHTOK_ERR;
+     }
+     
+     if (ctrl & WINBIND_DEBUG_ARG) {
+
+            /* Let's not give too much away in the log file */
+
+#ifdef DEBUG_PASSWORD
+        _pam_log(LOG_INFO, "Verify user `%s' with password `%s'",
+                 username, password);
+#else
+        _pam_log(LOG_INFO, "Verify user `%s'", username);
+#endif
+     }
+
+     if (ctrl & WINBIND_REQUIRED_MEMBERSHIP) {
+            
+         for ( i=0; i<argc; i++ ) {
+
+            if ((strncmp(argv[i], "require_membership_of", strlen("require_membership_of")) == 0) ||
+                (strncmp(argv[i], "require-membership-of", strlen("require-membership-of")) == 0)) {
+
+               char *p;
+               char *parm = strdup(argv[i]);
+
+               if ( (p = strchr( parm, '=' )) == NULL) {
+                  _pam_log(LOG_INFO, "no \"=\" delimiter for \"require_membership_of\" found\n");
+                  break;
+               }
+
+               member = strdup(p+1);
+            }
+         }
+     }
+
+     /* Now use the username to look up password */
+     retval = winbind_auth_request(username, password, member, ctrl);
+     if (retval == PAM_NEW_AUTHTOK_REQD ||
+        retval == PAM_AUTHTOK_EXPIRED) {
+       
+       char *buf;
+                       
+       if (!asprintf(&buf, "%d", retval)) {
+               return PAM_BUF_ERR;
+       }
+
+       pam_set_data( pamh, PAM_WINBIND_NEW_AUTHTOK_REQD, (void *)buf, _pam_winbind_cleanup_func);
+
+       return PAM_SUCCESS;
+     }
+     
+     return retval;
+}
+
+PAM_EXTERN
+int pam_sm_setcred(pam_handle_t *pamh, int flags,
+                  int argc, const char **argv)
+{
+    return PAM_SUCCESS;
+}
+
+/*
+ * Account management. We want to verify that the account exists 
+ * before returning PAM_SUCCESS
+ */
+PAM_EXTERN
+int pam_sm_acct_mgmt(pam_handle_t *pamh, int flags,
+                  int argc, const char **argv)
+{
+    const char *username;
+    void *tmp = NULL;
+
+    int retval = PAM_USER_UNKNOWN;
+
+    /* parse arguments */
+    int ctrl = _pam_parse(argc, argv);
+
+    /* Get the username */
+    retval = pam_get_user(pamh, &username, NULL);
+    if ((retval != PAM_SUCCESS) || (!username)) {
+       if (ctrl & WINBIND_DEBUG_ARG)
+           _pam_log(LOG_DEBUG,"can not get the username");
+       return PAM_SERVICE_ERR;
+    }
+
+    /* Verify the username */
+    retval = valid_user(username);
+    switch (retval) {
+       case -1:
+           /* some sort of system error. The log was already printed */
+           return PAM_SERVICE_ERR;
+       case 1:
+           /* the user does not exist */
+           if (ctrl & WINBIND_DEBUG_ARG)
+               _pam_log(LOG_NOTICE, "user `%s' not found",
+                        username);
+           if (ctrl & WINBIND_UNKNOWN_OK_ARG)
+               return PAM_IGNORE;
+           return PAM_USER_UNKNOWN;
+       case 0:
+           pam_get_data( pamh, PAM_WINBIND_NEW_AUTHTOK_REQD, (const void **)&tmp);
+
+           if (tmp != NULL) {
+               retval = atoi(tmp);
+               switch (retval) {
+               case PAM_AUTHTOK_EXPIRED:
+                    /* fall through, since new token is required in this case */
+               case PAM_NEW_AUTHTOK_REQD:
+                    _pam_log(LOG_WARNING, "pam_sm_acct_mgmt success but %s is set",
+                             PAM_WINBIND_NEW_AUTHTOK_REQD);
+                    _pam_log(LOG_NOTICE, "user '%s' needs new password", username);
+                    /* PAM_AUTHTOKEN_REQD does not exist, but is documented in the manpage */
+                    return PAM_NEW_AUTHTOK_REQD;
+               default:
+                    _pam_log(LOG_WARNING, "pam_sm_acct_mgmt success");
+                    _pam_log(LOG_NOTICE, "user '%s' granted access", username);
+                    return PAM_SUCCESS;
+               }
+           }
+
+           /* Otherwise, the authentication looked good */
+           _pam_log(LOG_NOTICE, "user '%s' granted access", username);
+           return PAM_SUCCESS;
+       default:
+           /* we don't know anything about this return value */
+           _pam_log(LOG_ERR, "internal module error (retval = %d, user = `%s'",
+                    retval, username);
+           return PAM_SERVICE_ERR;
+    }
+    
+    /* should not be reached */
+    return PAM_IGNORE;
+}
+PAM_EXTERN
+int pam_sm_open_session(pam_handle_t *pamh, int flags,
+                int argc, const char **argv)
+{
+        /* parse arguments */
+        int ctrl = _pam_parse(argc, argv);
+        if (ctrl & WINBIND_DEBUG_ARG)
+              _pam_log(LOG_DEBUG,"libpam_winbind:pam_sm_open_session handler");
+        return PAM_SUCCESS;
+}
+PAM_EXTERN
+int pam_sm_close_session(pam_handle_t *pamh, int flags,
+                int argc, const char **argv)
+{
+        /* parse arguments */
+        int ctrl = _pam_parse(argc, argv);
+        if (ctrl & WINBIND_DEBUG_ARG)
+              _pam_log(LOG_DEBUG,"libpam_winbind:pam_sm_close_session handler");
+        return PAM_SUCCESS;
+}
+
+
+
+PAM_EXTERN int pam_sm_chauthtok(pam_handle_t * pamh, int flags,
+                               int argc, const char **argv)
+{
+       unsigned int lctrl;
+       int retval;
+       unsigned int ctrl = _pam_parse(argc, argv);
+
+       /* <DO NOT free() THESE> */
+       const char *user;
+       const char *member = NULL;
+       char *pass_old, *pass_new;
+       /* </DO NOT free() THESE> */
+
+       char *Announce;
+       
+       int retry = 0;
+
+       /*
+        * First get the name of a user
+        */
+       retval = pam_get_user(pamh, &user, "Username: ");
+       if (retval == PAM_SUCCESS) {
+               if (user == NULL) {
+                       _pam_log(LOG_ERR, "username was NULL!");
+                       return PAM_USER_UNKNOWN;
+               }
+               if (retval == PAM_SUCCESS && on(WINBIND_DEBUG_ARG, ctrl))
+                       _pam_log(LOG_DEBUG, "username [%s] obtained",
+                                user);
+       } else {
+               if (on(WINBIND_DEBUG_ARG, ctrl))
+                       _pam_log(LOG_DEBUG,
+                                "password - could not identify user");
+               return retval;
+       }
+
+       /*
+        * obtain and verify the current password (OLDAUTHTOK) for
+        * the user.
+        */
+
+       if (flags & PAM_PRELIM_CHECK) {
+               
+               /* instruct user what is happening */
+#define greeting "Changing password for "
+               Announce = (char *) malloc(sizeof(greeting) + strlen(user));
+               if (Announce == NULL) {
+               _pam_log(LOG_CRIT, 
+                        "password - out of memory");
+               return PAM_BUF_ERR;
+               }
+               (void) strcpy(Announce, greeting);
+               (void) strcpy(Announce + sizeof(greeting) - 1, user);
+#undef greeting
+               
+               lctrl = ctrl | WINBIND__OLD_PASSWORD;
+               retval = _winbind_read_password(pamh, lctrl
+                                               ,Announce
+                                               ,"(current) NT password: "
+                                               ,NULL
+                                               ,(const char **) &pass_old);
+               free(Announce);
+               
+               if (retval != PAM_SUCCESS) {
+                       _pam_log(LOG_NOTICE
+                                ,"password - (old) token not obtained");
+                       return retval;
+               }
+               /* verify that this is the password for this user */
+               
+               retval = winbind_auth_request(user, pass_old, member, ctrl);
+               
+               if (retval != PAM_ACCT_EXPIRED 
+                   && retval != PAM_AUTHTOK_EXPIRED
+                   && retval != PAM_NEW_AUTHTOK_REQD 
+                   && retval != PAM_SUCCESS) {
+                       pass_old = NULL;
+                       return retval;
+               }
+               
+               retval = pam_set_item(pamh, PAM_OLDAUTHTOK, (const void *) pass_old);
+               pass_old = NULL;
+               if (retval != PAM_SUCCESS) {
+                       _pam_log(LOG_CRIT, 
+                                "failed to set PAM_OLDAUTHTOK");
+               }
+       } else if (flags & PAM_UPDATE_AUTHTOK) {
+       
+               /*
+                * obtain the proposed password
+                */
+               
+               /*
+                * get the old token back. 
+                */
+               
+               retval = pam_get_item(pamh, PAM_OLDAUTHTOK
+                                     ,(const void **) &pass_old);
+               
+               if (retval != PAM_SUCCESS) {
+                       _pam_log(LOG_NOTICE, "user not authenticated");
+                       return retval;
+               }
+               
+               lctrl = ctrl;
+               
+               if (on(WINBIND_USE_AUTHTOK_ARG, lctrl)) {
+                       lctrl |= WINBIND_USE_FIRST_PASS_ARG;
+               }
+               retry = 0;
+               retval = PAM_AUTHTOK_ERR;
+               while ((retval != PAM_SUCCESS) && (retry++ < MAX_PASSWD_TRIES)) {
+                       /*
+                        * use_authtok is to force the use of a previously entered
+                        * password -- needed for pluggable password strength checking
+                        */
+                       
+                       retval = _winbind_read_password(pamh, lctrl
+                                                       ,NULL
+                                                       ,"Enter new NT password: "
+                                                       ,"Retype new NT password: "
+                                                       ,(const char **) &pass_new);
+                       
+                       if (retval != PAM_SUCCESS) {
+                               if (on(WINBIND_DEBUG_ARG, ctrl)) {
+                                       _pam_log(LOG_ALERT
+                                                ,"password - new password not obtained");
+                               }
+                               pass_old = NULL;/* tidy up */
+                               return retval;
+                       }
+
+                       /*
+                        * At this point we know who the user is and what they
+                        * propose as their new password. Verify that the new
+                        * password is acceptable.
+                        */
+                       
+                       if (pass_new[0] == '\0') {/* "\0" password = NULL */
+                               pass_new = NULL;
+                       }
+               }
+               
+               /*
+                * By reaching here we have approved the passwords and must now
+                * rebuild the password database file.
+                */
+
+               retval = winbind_chauthtok_request(user, pass_old, pass_new, ctrl);
+               _pam_overwrite(pass_new);
+               _pam_overwrite(pass_old);
+               pass_old = pass_new = NULL;
+       } else {
+               retval = PAM_SERVICE_ERR;
+       }
+       
+       return retval;
+}
+
+#ifdef PAM_STATIC
+
+/* static module data */
+
+struct pam_module _pam_winbind_modstruct = {
+     MODULE_NAME,
+     pam_sm_authenticate,
+     pam_sm_setcred,
+     pam_sm_acct_mgmt,
+     pam_sm_open_session,
+     pam_sm_close_session,
+     pam_sm_chauthtok
+};
+
+#endif
+
+/*
+ * Copyright (c) Andrew Tridgell  <tridge@samba.org>   2000
+ * Copyright (c) Tim Potter       <tpot@samba.org>     2000
+ * Copyright (c) Andrew Bartlettt <abartlet@samba.org> 2002
+ * Copyright (c) Jan Rêkorajski 1999.
+ * Copyright (c) Andrew G. Morgan 1996-8.
+ * Copyright (c) Alex O. Yuriev, 1996.
+ * Copyright (c) Cristian Gafton 1996.
+ * Copyright (C) Elliot Lee <sopwith@redhat.com> 1996, Red Hat Software. 
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, and the entire permission notice in its entirety,
+ *    including the disclaimer of warranties.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote
+ *    products derived from this software without specific prior
+ *    written permission.
+ *
+ * ALTERNATIVELY, this product may be distributed under the terms of
+ * the GNU Public License, in which case the provisions of the GPL are
+ * required INSTEAD OF the above restrictions.  (This clause is
+ * necessary due to a potential bad interaction between the GPL and
+ * the restrictions contained in a BSD-style copyright.)
+ *
+ * THIS SOFTWARE IS PROVIDED `AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */