pam_modules/dial_auth/dial_auth.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <crypt.h>
#include <pwd.h>
#include <shadow.h>
#include <string.h>
#include <stdlib.h>
#include <syslog.h>
#include <security/pam_appl.h>
#include <security/pam_modules.h>
#include "../../libpam/pam_impl.h"

#include <libintl.h>

/*
 * Various useful files and string constants
 */
#define DIAL_FILE   "/etc/dialups"
#define DPASS_FILE  "/etc/d_passwd"
#define SHELL       "/usr/bin/sh"
#define SCPYN(a, b) (void) strncpy(a, b, sizeof (a))

/*
 * pam_sm_authenticate  - This is the top level function in the
 *          module called by pam_auth_port in the framework
 *          Returns: PAM_AUTH_ERR on failure, 0 on success
 */
/*ARGSUSED*/
int
pam_sm_authenticate(pam_handle_t *pamh, int flags, int argc, const char **argv)
{
    char    *ttyn, *user;
    FILE    *fp;
    char    defpass[30];
    char    line[80];
    char    *p1 = NULL, *p2 = NULL;
    struct passwd   pwd;
    char    pwd_buffer[1024];
    char    *password = NULL;
    int retcode;
    int i;
    int debug = 0;
    int res;

    for (i = 0; i < argc; i++) {
        if (strcasecmp(argv[i], "debug") == 0)
            debug = 1;
        else
            syslog(LOG_DEBUG, "illegal option %s", argv[i]);
    }

    if ((retcode = pam_get_user(pamh, &user, NULL))
                    != PAM_SUCCESS ||
        (retcode = pam_get_item(pamh, PAM_TTY, (void **)&ttyn))
                    != PAM_SUCCESS)
        return (retcode);

    if (debug) {
        syslog(LOG_DEBUG,
            "Dialpass authenticate user = %s, ttyn = %s",
            user ? user : "NULL", ttyn ? ttyn : "NULL");
    }

    if (ttyn == NULL || *ttyn == '\0') {
        char *service;

        (void) pam_get_item(pamh, PAM_SERVICE, (void **)&service);
        syslog(LOG_ERR, "pam_dial_auth: terminal-device not specified"
            "by %s, returning %s.", service,
            pam_strerror(pamh, PAM_SERVICE_ERR));
        return (PAM_SERVICE_ERR);
    }
    if (getpwnam_r(user, &pwd, pwd_buffer, sizeof (pwd_buffer)) == NULL)
        return (PAM_USER_UNKNOWN);

    if ((fp = fopen(DIAL_FILE, "rF")) == NULL)
        return (PAM_IGNORE);

    while ((p1 = fgets(line, sizeof (line), fp)) != NULL) {
        while (*p1 != '\n' && *p1 != ' ' && *p1 != '\t')
            p1++;
        *p1 = '\0';
        if (strcmp(line, ttyn) == 0)
            break;
    }

    (void) fclose(fp);

    if ((fp = fopen(DPASS_FILE, "rF")) == NULL) {
        syslog(LOG_ERR, "pam_dial_auth: %s without %s, returning %s.",
            DIAL_FILE, DPASS_FILE,
            pam_strerror(pamh, PAM_SYSTEM_ERR));
        (void) memset(line, 0, sizeof (line));
        return (PAM_SYSTEM_ERR);
    }

    if (p1 == NULL) {
        (void) fclose(fp);
        (void) memset(line, 0, sizeof (line));
        return (PAM_IGNORE);
    }

    defpass[0] = '\0';

    while ((p1 = fgets(line, sizeof (line)-1, fp)) != NULL) {
        while (*p1 && *p1 != ':')
            p1++;
        *p1++ = '\0';
        p2 = p1;
        while (*p1 && *p1 != ':')
            p1++;
        *p1 = '\0';
        if (pwd.pw_shell != NULL && strcmp(pwd.pw_shell, line) == 0)
            break;

        if (strcmp(SHELL, line) == 0)
            SCPYN(defpass, p2);
        p2 = NULL;
    }

    (void) memset(line, 0, sizeof (line));
    (void) fclose(fp);

    if (p2 == NULL)
        p2 = defpass;

    if (*p2 != '\0') {
        res = __pam_get_authtok(pamh, PAM_PROMPT, PAM_AUTHTOK,
            dgettext(TEXT_DOMAIN, "Dialup Password: "), &password);

        if (res != PAM_SUCCESS) {
            return (res);
        }

        if (strcmp(crypt(password, p2), p2) != 0) {
            (void) memset(password, 0, strlen(password));
            free(password);
            return (PAM_AUTH_ERR);
        }
        (void) memset(password, 0, strlen(password));
        free(password);
    }

    return (PAM_SUCCESS);
}

/*
 * dummy pam_sm_setcred - does nothing
 */
/*ARGSUSED*/
int
pam_sm_setcred(pam_handle_t *pamh, int flags, int argc, const char **argv)
{
    return (PAM_IGNORE);
}