source: openpam/trunk/lib/pam_get_authtok.c @ 235

/*-
 * Copyright (c) 2002,2003 Networks Associates Technology, Inc.
 * All rights reserved.
 *
 * This software was developed for the FreeBSD Project by ThinkSec AS and
 * Network Associates Laboratories, the Security Research Division of
 * Network Associates, Inc.  under DARPA/SPAWAR contract N66001-01-C-8035
 * ("CBOSS"), as part of the DARPA CHATS research program.
 *
 * 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, this list of conditions and the following disclaimer.
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
 *
 * $P4: //depot/projects/openpam/lib/pam_get_authtok.c#24 $
 */

#include <sys/param.h>

#include <stdlib.h>
#include <string.h>

#include <security/pam_appl.h>
#include <security/openpam.h>

#include "openpam_impl.h"

const char authtok_prompt[] = "Password:";
const char oldauthtok_prompt[] = "Old Password:";
const char newauthtok_prompt[] = "New Password:";

/*
 * OpenPAM extension
 *
 * Retrieve authentication token
 */

int
pam_get_authtok(pam_handle_t *pamh,
        int item,
        const char **authtok,
        const char *prompt)
{
        const void *oldauthtok;
        const char *default_prompt;
        char *resp, *resp2;
        int pitem, r, style, twice;

        ENTER();
        if (pamh == NULL || authtok == NULL)
                RETURNC(PAM_SYSTEM_ERR);
        *authtok = NULL;
        twice = 0;
        switch (item) {
        case PAM_AUTHTOK:
                pitem = PAM_AUTHTOK_PROMPT;
                default_prompt = authtok_prompt;
                r = pam_get_item(pamh, PAM_OLDAUTHTOK, &oldauthtok);
                if (r == PAM_SUCCESS && oldauthtok != NULL) {
                        default_prompt = newauthtok_prompt;
                        twice = 1;
                }
                break;
        case PAM_OLDAUTHTOK:
                pitem = PAM_OLDAUTHTOK_PROMPT;
                default_prompt = oldauthtok_prompt;
                twice = 0;
                break;
        default:
                RETURNC(PAM_SYMBOL_ERR);
        }
        if (openpam_get_option(pamh, "try_first_pass") ||
            openpam_get_option(pamh, "use_first_pass")) {
                r = pam_get_item(pamh, item, (const void **)authtok);
                if (r == PAM_SUCCESS && *authtok != NULL)
                        RETURNC(PAM_SUCCESS);
                else if (openpam_get_option(pamh, "use_first_pass"))
                        RETURNC(r == PAM_SUCCESS ? PAM_AUTH_ERR : r);
        }
        if (prompt == NULL) {
                r = pam_get_item(pamh, pitem, (const void **)&prompt);
                if (r != PAM_SUCCESS || prompt == NULL)
                        prompt = default_prompt;
        }
        style = openpam_get_option(pamh, "echo_pass") ?
            PAM_PROMPT_ECHO_ON : PAM_PROMPT_ECHO_OFF;
        r = pam_prompt(pamh, style, &resp, "%s", prompt);
        if (r != PAM_SUCCESS)
                RETURNC(r);
        if (twice) {
                r = pam_prompt(pamh, style, &resp2, "Retype %s", prompt);
                if (r != PAM_SUCCESS) {
                        FREE(resp);
                        RETURNC(r);
                }
                if (strcmp(resp, resp2) != 0)
                        FREE(resp);
                FREE(resp2);
        }
        if (resp == NULL)
                RETURNC(PAM_TRY_AGAIN);
        r = pam_set_item(pamh, item, resp);
        FREE(resp);
        if (r != PAM_SUCCESS)
                RETURNC(r);
        r = pam_get_item(pamh, item, (const void **)authtok);
        RETURNC(r);
}

/*
 * Error codes:
 *
 *      =pam_get_item
 *      =pam_prompt
 *      =pam_set_item
 *      !PAM_SYMBOL_ERR
 *      PAM_TRY_AGAIN
 */

/**
 * The =pam_get_authtok function returns the cached authentication token,
 * or prompts the user if no token is currently cached.  Either way, a
 * pointer to the authentication token is stored in the location pointed
 * to by the =authtok argument.
 *
 * The =item argument must have one of the following values:
 *
 *      =PAM_AUTHTOK:
 *              Returns the current authentication token, or the new token
 *              when changing authentication tokens.
 *      =PAM_OLDAUTHTOK:
 *              Returns the previous authentication token when changing
 *              authentication tokens.
 *
 * The =prompt argument specifies a prompt to use if no token is cached.
 * If it is =NULL, the =PAM_AUTHTOK_PROMPT or =PAM_OLDAUTHTOK_PROMPT item,
 * as appropriate, will be used.  If that item is also =NULL, a hardcoded
 * default prompt will be used.
 *
 * If =item is set to =PAM_AUTHTOK and there is a non-null =PAM_OLDAUTHTOK
 * item, =pam_get_authtok will ask the user to confirm the new token by
 * retyping it.  If there is a mismatch, =pam_get_authtok will return
 * =PAM_TRY_AGAIN.
 *
 * >pam_get_item
 * >pam_get_user
 */