pam_modules/krb5/krb5_acct_mgmt.c

	krb5_acct_mgmt.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (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 2004 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

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


#include <kadm5/admin.h>
#include <krb5.h>

#include <security/pam_appl.h>
#include <security/pam_modules.h>
#include <security/pam_impl.h>
#include <syslog.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <pwd.h>
#include <libintl.h>
#include <netdb.h>
#include "utils.h"
#include <shadow.h>

#include "krb5_repository.h"

#define KRB5_AUTOMIGRATE_DATA   "SUNW-KRB5-AUTOMIGRATE-DATA"

/*
 * pam_sm_acct_mgmt   main account managment routine.
 */

static int
fetch_princ_entry(
    char *princ_str,
    char *password,
    kadm5_principal_ent_rec *prent, /* out */
    krb5_timestamp *now, /* out */
    int debug)

{
    kadm5_ret_t     code;
    krb5_principal      princ = 0;
    char            admin_realm[1024];
    char            kprinc[2*MAXHOSTNAMELEN];
    char            *cpw_service;
    void            *server_handle;
    krb5_context        context;
    kadm5_config_params params;

    if (code = krb5_init_context(&context)) {
        return (PAM_SYSTEM_ERR);
    }

    if ((code = get_kmd_kuser(context, (const char *)princ_str, kprinc,
        2*MAXHOSTNAMELEN)) != 0) {
        return (code);
    }

    code = krb5_parse_name(context, kprinc, &princ);
    if (code != 0) {
        krb5_free_context(context);
        return (PAM_SYSTEM_ERR);
    }

    if (strlen(password) == 0) {
        krb5_free_principal(context, princ);
        krb5_free_context(context);
        if (debug)
            syslog(LOG_DEBUG,
                "PAM-KRB5 (acct): fetch_princ_entry: pwlen=0");
        return (PAM_AUTH_ERR);
    }

    (void) strlcpy(admin_realm,
            krb5_princ_realm(context, princ)->data,
            sizeof (admin_realm));

    (void) memset((char *)&params, 0, sizeof (params));
    params.mask |= KADM5_CONFIG_REALM;
    params.realm = admin_realm;

    if (kadm5_get_cpw_host_srv_name(context, admin_realm, &cpw_service)) {
        syslog(LOG_ERR,
            dgettext(TEXT_DOMAIN,
            "PAM-KRB5 (acct):  unable to get host based "
            "service name for realm '%s'"),
            admin_realm);
        krb5_free_principal(context, princ);
        krb5_free_context(context);
        return (PAM_SYSTEM_ERR);
    }

    code = kadm5_init_with_password(kprinc, password, cpw_service,
                    &params, KADM5_STRUCT_VERSION,
                    KADM5_API_VERSION_2, &server_handle);
    if (code != 0) {
        if (debug)
            syslog(LOG_DEBUG,
                "PAM-KRB5 (acct): fetch_princ_entry: "
                "init_with_pw failed: code = %d", code);
        krb5_free_principal(context, princ);
        krb5_free_context(context);
        return ((code == KADM5_BAD_PASSWORD) ?
            PAM_AUTH_ERR : PAM_SYSTEM_ERR);
    }

    if (_kadm5_get_kpasswd_protocol(server_handle) != KRB5_CHGPWD_RPCSEC) {
        if (debug)
            syslog(LOG_DEBUG,
                "PAM-KRB5 (acct): fetch_princ_entry: "
                "non-RPCSEC_GSS chpw server, can't get "
                "princ entry");
        (void) kadm5_destroy(server_handle);
        krb5_free_principal(context, princ);
        krb5_free_context(context);
        return (PAM_SYSTEM_ERR);
    }

    code = kadm5_get_principal(server_handle, princ, prent,
                KADM5_PRINCIPAL_NORMAL_MASK);

    if (code != 0) {
        (void) kadm5_destroy(server_handle);
        krb5_free_principal(context, princ);
        krb5_free_context(context);
        return ((code == KADM5_UNK_PRINC) ?
            PAM_USER_UNKNOWN : PAM_SYSTEM_ERR);
    }

    if (code = krb5_timeofday(context, now)) {
        (void) kadm5_destroy(server_handle);
        krb5_free_principal(context, princ);
        krb5_free_context(context);
        syslog(LOG_ERR,
            dgettext(TEXT_DOMAIN,
                "PAM-KRB5 (acct): krb5_timeofday fail: code=%d"),
            code);
        return (PAM_SYSTEM_ERR);
    }

    (void) kadm5_destroy(server_handle);
    krb5_free_principal(context, princ);
    krb5_free_context(context);

    return (PAM_SUCCESS);
}

/*
 * exp_warn
 *
 * warn the user if her pw is set to expire
 *
 * We use the kadm protocol and chpw svc to fetch the user's KDC db
 * entry.  The user's default perms on the KDC db should allow this.
 * Note since the SEAM kadm API uses rpcsec_gss (which is diff from
 * what MS and MIT 1.2 and before uses), this probably only works
 * with a SEAM KDC.
 */

static int
exp_warn(
    pam_handle_t *pamh,
    char *user,
    char *password,
    int debug)

{
    int err;
    kadm5_principal_ent_rec prent;
    krb5_timestamp  now, days;
    char    messages[PAM_MAX_NUM_MSG][PAM_MAX_MSG_SIZE];

    if (debug)
        syslog(LOG_DEBUG,
            "PAM-KRB5 (acct): exp_warn start: user = '%s'",
            user ? user : "<null>");

    if (!pamh || !user || !password) {
        err = PAM_SERVICE_ERR;
        goto out;
    }

    (void) memset(&prent, 0, sizeof (prent));
    if ((err = fetch_princ_entry(user, password, &prent,
                    &now, debug)) != PAM_SUCCESS) {
        if (debug)
            syslog(LOG_DEBUG,
                "PAM-KRB5 (acct): exp_warn: fetch_pr failed %d",
                err);
        goto out;
    }

    if (debug)
        syslog(LOG_DEBUG,
            "PAM-KRB5 (acct): exp_warn: fetch_princ success:"
            " princ exp=%ld pw_exp = %ld, now =%ld, days=%ld",
            prent.princ_expire_time,
            prent.pw_expiration, now,
            prent.pw_expiration > 0
            ? ((prent.pw_expiration - now) / DAY)
            : 0);

    /* warn user if principal's pw is set to expire */
    if (prent.pw_expiration > 0) {
        days = (prent.pw_expiration - now) / DAY;
        if (days <= 0)
            (void) snprintf(messages[0],
                sizeof (messages[0]),
                dgettext(TEXT_DOMAIN,
        "Your Kerberos password will expire within 24 hours.\n"));
        else if (days == 1)
            (void) snprintf(messages[0],
                sizeof (messages[0]),
                dgettext(TEXT_DOMAIN,
            "Your Kerberos password will expire in 1 day.\n"));
        else
            (void) snprintf(messages[0],
                sizeof (messages[0]),
                dgettext(TEXT_DOMAIN,
            "Your Kerberos password will expire in %d days.\n"),
                (int)days);

        (void) __pam_display_msg(pamh, PAM_TEXT_INFO, 1,
                    messages, NULL);
    }

    /* things went smooth */
    err = PAM_SUCCESS;

out:
    if (debug)
        syslog(LOG_DEBUG,
            "PAM-KRB5 (acct): exp_warn end: err = %d", err);

    return (err);
}

/*
 * pam_krb5 acct_mgmt
 *
 * we do
 *    - check if pw expired (flag set in auth)
 *    - warn user if pw is set to expire
 *
 * notes
 *    - we require the auth module to have already run (sets module data)
 *    - we don't worry about an expired princ cuz if that's the case,
 *      auth would have failed
 */
int
pam_sm_acct_mgmt(
    pam_handle_t *pamh,
    int flags,
    int argc,
    const char **argv)

{
    char *user = NULL;
    char *userdata = NULL;
    int err;
    int i;
    krb5_module_data_t *kmd = NULL;
    char    messages[PAM_MAX_NUM_MSG][PAM_MAX_MSG_SIZE];
    int debug = 0;  /* pam.conf entry option */
    int nowarn = 0; /* pam.conf entry option, no expire warnings */
    pam_repository_t    *rep_data = NULL;

    for (i = 0; i < argc; i++) {
        if (strcasecmp(argv[i], "debug") == 0)
            debug = 1;
        else if (strcasecmp(argv[i], "nowarn") == 0) {
            nowarn = 1;
            flags = flags | PAM_SILENT;
        } else {
            syslog(LOG_ERR,
                "PAM-KRB5 (acct): illegal option %s",
                argv[i]);
        }
    }

    if (debug)
        syslog(LOG_DEBUG,
            "PAM-KRB5 (acct): debug=%d, nowarn=%d",
            debug, nowarn);

    err = pam_get_item(pamh, PAM_REPOSITORY, (void **)&rep_data);
    if (rep_data != NULL) {
        /*
         * If the repository is not ours,
         * return PAM_IGNORE.
         */
        if (strcmp(rep_data->type, KRB5_REPOSITORY_NAME) != 0) {
            if (debug)
                syslog(LOG_DEBUG, "PAM-KRB5 (acct): wrong"
                    "repository found (%s), returning "
                    "PAM_IGNORE", rep_data->type);
            return (PAM_IGNORE);
        }
    }


    /* get user name */
    if ((err = pam_get_item(pamh, PAM_USER, (void **) &user))
        != PAM_SUCCESS) {
        syslog(LOG_ERR, dgettext(TEXT_DOMAIN,
                    "PAM-KRB5 (acct):"
                    " get user failed: err=%d"),
            err);
        goto out;
    }

    if (user == NULL) {
        err = PAM_USER_UNKNOWN;
        goto out;
    }

    /* get pam_krb5_migrate specific data */
    err = pam_get_data(pamh, KRB5_AUTOMIGRATE_DATA,
                    (const void **)&userdata);
    if (err != PAM_SUCCESS) {
        if (debug)
            syslog(LOG_DEBUG, dgettext(TEXT_DOMAIN,
                "PAM-KRB5 (acct): "
                "no module data for KRB5_AUTOMIGRATE_DATA"));
    } else {
        /*
         * We try and reauthenticate, since this user has a
         * newly created krb5 principal via the pam_krb5_migrate
         * auth module. That way, this new user will have fresh
         * creds (assuming pam_sm_authenticate() succeeds).
         */
        if (strcmp(user, userdata) == 0)
            (void) pam_sm_authenticate(pamh, flags, argc,
                    (const char **)argv);
        else
            if (debug)
                syslog(LOG_DEBUG, dgettext(TEXT_DOMAIN,
                "PAM-KRB5 (acct): PAM_USER %s"
                "does not match user %s from pam_get_data()"),
                user, (char *)userdata);
    }

    /* get krb5 module data  */
    if ((err = pam_get_data(pamh, KRB5_DATA, (const void **)&kmd))
        != PAM_SUCCESS) {
        if (err == PAM_NO_MODULE_DATA) {
            /*
             * pam_auth never called (possible config
             * error; no pam_krb5 auth entry in pam.conf)
             * or
             * auth module returned before module data
             * was instantiated (normal for auth 'acceptor')
             */
            if (debug)
                syslog(LOG_DEBUG,
                    "PAM-KRB5 (acct): no module data");
            err = PAM_IGNORE;
            goto out;
        } else {
            syslog(LOG_ERR,
                dgettext(TEXT_DOMAIN,
                    "PAM-KRB5 (acct): get module"
                    " data failed: err=%d"),
                err);
        }
        goto out;
    }

    debug = debug || kmd->debug;

    /*
     * auth mod set status to ignore, most likely cuz root key is
     * in keytab, so skip other checks and return ignore
     */
    if (kmd->auth_status == PAM_IGNORE) {
        if (debug)
            syslog(LOG_DEBUG,
                "PAM-KRB5 (acct): kmd auth_status is IGNORE");
        err = PAM_IGNORE;
        goto out;
    }

    /*
     * age_status will be set to PAM_NEW_AUTHTOK_REQD in pam_krb5's
     * 'auth' if the user's key/pw has expired and needs to be changed
     */
    if (kmd->age_status == PAM_NEW_AUTHTOK_REQD) {
        if (!nowarn) {
            (void) snprintf(messages[0], sizeof (messages[0]),
                dgettext(TEXT_DOMAIN,
                "Your Kerberos password has expired.\n"));
            (void) __pam_display_msg(pamh, PAM_TEXT_INFO,
                    1, messages, NULL);
        }
        err = PAM_NEW_AUTHTOK_REQD;
        goto out;
    }

    if (!(flags & PAM_SILENT) && !nowarn && kmd->password) {
        /* if we fail, let it slide, it's only a warning brah */
        (void) exp_warn(pamh, user, kmd->password, debug);
    }

    /* everything a-ok */
    err = PAM_SUCCESS;

out:
    if (debug)
        syslog(LOG_DEBUG,
            "PAM-KRB5 (acct): end: %s", pam_strerror(pamh, err));

    return (err);
}