/*-
 * Copyright (c) 1991, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * 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. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 *
 */

#if 0
#ifndef lint
static const char sccsid[] = "@(#)auth.c        8.3 (Berkeley) 5/30/95";
#endif /* not lint */
#endif
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");


/*
 * Copyright (C) 1990 by the Massachusetts Institute of Technology
 *
 * Export of this software from the United States of America is assumed
 * to require a specific license from the United States Government.
 * It is the responsibility of any person or organization contemplating
 * export to obtain such a license before exporting.
 *
 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
 * distribute this software and its documentation for any purpose and
 * without fee is hereby granted, provided that the above copyright
 * notice appear in all copies and that both that copyright notice and
 * this permission notice appear in supporting documentation, and that
 * the name of M.I.T. not be used in advertising or publicity pertaining
 * to distribution of the software without specific, written prior
 * permission.  M.I.T. makes no representations about the suitability of
 * this software for any purpose.  It is provided "as is" without express
 * or implied warranty.
 */


#ifdef  AUTHENTICATION
#define AUTH_NAMES
#include <sys/types.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/telnet.h>

#include "encrypt.h"
#include "auth.h"
#include "misc-proto.h"
#include "auth-proto.h"

#define typemask(x)     ((x) > 0 ? 1 << ((x)-1) : 0)

#ifdef  KRB4_ENCPWD
extern krb4encpwd_init();
extern krb4encpwd_send();
extern krb4encpwd_is();
extern krb4encpwd_reply();
extern krb4encpwd_status();
extern krb4encpwd_printsub();
#endif

#ifdef  RSA_ENCPWD
extern rsaencpwd_init();
extern rsaencpwd_send();
extern rsaencpwd_is();
extern rsaencpwd_reply();
extern rsaencpwd_status();
extern rsaencpwd_printsub();
#endif

int auth_debug_mode = 0;
static  const char      *Name = "Noname";
static  int     Server = 0;
static  Authenticator   *authenticated = 0;
static  int     authenticating = 0;
static  int     validuser = 0;
static  unsigned char   _auth_send_data[256];
static  unsigned char   *auth_send_data;
static  int     auth_send_cnt = 0;

int auth_onoff(char *type, int on);
void auth_encrypt_user(char *name);

/*
 * Authentication types supported.  Plese note that these are stored
 * in priority order, i.e. try the first one first.
 */
Authenticator authenticators[] = {
#ifdef  KRB5
# ifdef ENCRYPTION
        { AUTHTYPE_KERBEROS_V5, AUTH_WHO_CLIENT|AUTH_HOW_MUTUAL,
                                kerberos5_init,
                                kerberos5_send_mutual,
                                kerberos5_is,
                                kerberos5_reply,
                                kerberos5_status,
                                kerberos5_printsub },
# endif /* ENCRYPTION */
        { AUTHTYPE_KERBEROS_V5, AUTH_WHO_CLIENT|AUTH_HOW_ONE_WAY,
                                kerberos5_init,
                                kerberos5_send_oneway,
                                kerberos5_is,
                                kerberos5_reply,
                                kerberos5_status,
                                kerberos5_printsub },
#endif
#ifdef  KRB4
# ifdef ENCRYPTION
        { AUTHTYPE_KERBEROS_V4, AUTH_WHO_CLIENT|AUTH_HOW_MUTUAL,
                                kerberos4_init,
                                kerberos4_send,
                                kerberos4_is,
                                kerberos4_reply,
                                kerberos4_status,
                                kerberos4_printsub },
# endif /* ENCRYPTION */
        { AUTHTYPE_KERBEROS_V4, AUTH_WHO_CLIENT|AUTH_HOW_ONE_WAY,
                                kerberos4_init,
                                kerberos4_send,
                                kerberos4_is,
                                kerberos4_reply,
                                kerberos4_status,
                                kerberos4_printsub },
#endif
#ifdef  KRB4_ENCPWD
        { AUTHTYPE_KRB4_ENCPWD, AUTH_WHO_CLIENT|AUTH_HOW_MUTUAL,
                                krb4encpwd_init,
                                krb4encpwd_send,
                                krb4encpwd_is,
                                krb4encpwd_reply,
                                krb4encpwd_status,
                                krb4encpwd_printsub },
#endif
#ifdef  RSA_ENCPWD
        { AUTHTYPE_RSA_ENCPWD, AUTH_WHO_CLIENT|AUTH_HOW_ONE_WAY,
                                rsaencpwd_init,
                                rsaencpwd_send,
                                rsaencpwd_is,
                                rsaencpwd_reply,
                                rsaencpwd_status,
                                rsaencpwd_printsub },
#endif
#ifdef SRA
        { AUTHTYPE_SRA, AUTH_WHO_CLIENT|AUTH_HOW_ONE_WAY,
                                sra_init,
                                sra_send,
                                sra_is,
                                sra_reply,
                                sra_status,
                                sra_printsub },

#endif
        { 0, 0, 0, 0, 0, 0, 0, 0 },
};

static Authenticator NoAuth = { 0, 0, 0, 0, 0, 0, 0, 0 };

static int      i_support = 0;
static int      i_wont_support = 0;

Authenticator *
findauthenticator(int type, int way)
{
        Authenticator *ap = authenticators;

        while (ap->type && (ap->type != type || ap->way != way))
                ++ap;
        return(ap->type ? ap : 0);
}

void
auth_init(const char *name, int server)
{
        Authenticator *ap = authenticators;

        Server = server;
        Name = name;

        i_support = 0;
        authenticated = 0;
        authenticating = 0;
        while (ap->type) {
                if (!ap->init || (*ap->init)(ap, server)) {
                        i_support |= typemask(ap->type);
                        if (auth_debug_mode)
                                printf(">>>%s: I support auth type %d %d\r\n",
                                        Name,
                                        ap->type, ap->way);
                }
                else if (auth_debug_mode)
                        printf(">>>%s: Init failed: auth type %d %d\r\n",
                                Name, ap->type, ap->way);
                ++ap;
        }
}

void
auth_disable_name(char *name)
{
        int x;
        for (x = 0; x < AUTHTYPE_CNT; ++x) {
                if (AUTHTYPE_NAME(x) && !strcasecmp(name, AUTHTYPE_NAME(x))) {
                        i_wont_support |= typemask(x);
                        break;
                }
        }
}

int
getauthmask(char *type, int *maskp)
{
        int x;

        if (AUTHTYPE_NAME(0) && !strcasecmp(type, AUTHTYPE_NAME(0))) {
                *maskp = -1;
                return(1);
        }

        for (x = 1; x < AUTHTYPE_CNT; ++x) {
                if (AUTHTYPE_NAME(x) && !strcasecmp(type, AUTHTYPE_NAME(x))) {
                        *maskp = typemask(x);
                        return(1);
                }
        }
        return(0);
}

int
auth_enable(char *type)
{
        return(auth_onoff(type, 1));
}

int
auth_disable(char *type)
{
        return(auth_onoff(type, 0));
}

int
auth_onoff(char *type, int on)
{
        int i, mask = -1;
        Authenticator *ap;

        if (!strcasecmp(type, "?") || !strcasecmp(type, "help")) {
                printf("auth %s 'type'\n", on ? "enable" : "disable");
                printf("Where 'type' is one of:\n");
                printf("\t%s\n", AUTHTYPE_NAME(0));
                mask = 0;
                for (ap = authenticators; ap->type; ap++) {
                        if ((mask & (i = typemask(ap->type))) != 0)
                                continue;
                        mask |= i;
                        printf("\t%s\n", AUTHTYPE_NAME(ap->type));
                }
                return(0);
        }

        if (!getauthmask(type, &mask)) {
                printf("%s: invalid authentication type\n", type);
                return(0);
        }
        if (on)
                i_wont_support &= ~mask;
        else
                i_wont_support |= mask;
        return(1);
}

int
auth_togdebug(int on)
{
        if (on < 0)
                auth_debug_mode ^= 1;
        else
                auth_debug_mode = on;
        printf("auth debugging %s\n", auth_debug_mode ? "enabled" : "disabled");
        return(1);
}

int
auth_status(void)
{
        Authenticator *ap;
        int i, mask;

        if (i_wont_support == -1)
                printf("Authentication disabled\n");
        else
                printf("Authentication enabled\n");

        mask = 0;
        for (ap = authenticators; ap->type; ap++) {
                if ((mask & (i = typemask(ap->type))) != 0)
                        continue;
                mask |= i;
                printf("%s: %s\n", AUTHTYPE_NAME(ap->type),
                        (i_wont_support & typemask(ap->type)) ?
                                        "disabled" : "enabled");
        }
        return(1);
}

/*
 * This routine is called by the server to start authentication
 * negotiation.
 */
void
auth_request(void)
{
        static unsigned char str_request[64] = { IAC, SB,
                                                 TELOPT_AUTHENTICATION,
                                                 TELQUAL_SEND, };
        Authenticator *ap = authenticators;
        unsigned char *e = str_request + 4;

        if (!authenticating) {
                authenticating = 1;
                while (ap->type) {
                        if (i_support & ~i_wont_support & typemask(ap->type)) {
                                if (auth_debug_mode) {
                                        printf(">>>%s: Sending type %d %d\r\n",
                                                Name, ap->type, ap->way);
                                }
                                *e++ = ap->type;
                                *e++ = ap->way;
                        }
                        ++ap;
                }
                *e++ = IAC;
                *e++ = SE;
                net_write(str_request, e - str_request);
                printsub('>', &str_request[2], e - str_request - 2);
        }
}

/*
 * This is called when an AUTH SEND is received.
 * It should never arrive on the server side (as only the server can
 * send an AUTH SEND).
 * You should probably respond to it if you can...
 *
 * If you want to respond to the types out of order (i.e. even
 * if he sends  LOGIN KERBEROS and you support both, you respond
 * with KERBEROS instead of LOGIN (which is against what the
 * protocol says)) you will have to hack this code...
 */
void
auth_send(unsigned char *data, int cnt)
{
        Authenticator *ap;
        static unsigned char str_none[] = { IAC, SB, TELOPT_AUTHENTICATION,
                                            TELQUAL_IS, AUTHTYPE_NULL, 0,
                                            IAC, SE };
        if (Server) {
                if (auth_debug_mode) {
                        printf(">>>%s: auth_send called!\r\n", Name);
                }
                return;
        }

        if (auth_debug_mode) {
                printf(">>>%s: auth_send got:", Name);
                printd(data, cnt); printf("\r\n");
        }

        /*
         * Save the data, if it is new, so that we can continue looking
         * at it if the authorization we try doesn't work
         */
        if (data < _auth_send_data ||
            data > _auth_send_data + sizeof(_auth_send_data)) {
                auth_send_cnt = (size_t)cnt > sizeof(_auth_send_data)
                                        ? sizeof(_auth_send_data)
                                        : cnt;
                memmove((void *)_auth_send_data, (void *)data, auth_send_cnt);
                auth_send_data = _auth_send_data;
        } else {
                /*
                 * This is probably a no-op, but we just make sure
                 */
                auth_send_data = data;
                auth_send_cnt = cnt;
        }
        while ((auth_send_cnt -= 2) >= 0) {
                if (auth_debug_mode)
                        printf(">>>%s: He supports %d\r\n",
                                Name, *auth_send_data);
                if ((i_support & ~i_wont_support) & typemask(*auth_send_data)) {
                        ap = findauthenticator(auth_send_data[0],
                                               auth_send_data[1]);
                        if (ap && ap->send) {
                                if (auth_debug_mode)
                                        printf(">>>%s: Trying %d %d\r\n",
                                                Name, auth_send_data[0],
                                                        auth_send_data[1]);
                                if ((*ap->send)(ap)) {
                                        /*
                                         * Okay, we found one we like
                                         * and did it.
                                         * we can go home now.
                                         */
                                        if (auth_debug_mode)
                                                printf(">>>%s: Using type %d\r\n",
                                                        Name, *auth_send_data);
                                        auth_send_data += 2;
                                        return;
                                }
                        }
                        /* else
                         *      just continue on and look for the
                         *      next one if we didn't do anything.
                         */
                }
                auth_send_data += 2;
        }
        net_write(str_none, sizeof(str_none));
        printsub('>', &str_none[2], sizeof(str_none) - 2);
        if (auth_debug_mode)
                printf(">>>%s: Sent failure message\r\n", Name);
        auth_finished(0, AUTH_REJECT);
}

void
auth_send_retry(void)
{
        /*
         * if auth_send_cnt <= 0 then auth_send will end up rejecting
         * the authentication and informing the other side of this.
         */
        auth_send(auth_send_data, auth_send_cnt);
}

void
auth_is(unsigned char *data, int cnt)
{
        Authenticator *ap;

        if (cnt < 2)
                return;

        if (data[0] == AUTHTYPE_NULL) {
                auth_finished(0, AUTH_REJECT);
                return;
        }

        if ((ap = findauthenticator(data[0], data[1]))) {
                if (ap->is)
                        (*ap->is)(ap, data+2, cnt-2);
        } else if (auth_debug_mode)
                printf(">>>%s: Invalid authentication in IS: %d\r\n",
                        Name, *data);
}

void
auth_reply(unsigned char *data, int cnt)
{
        Authenticator *ap;

        if (cnt < 2)
                return;

        if ((ap = findauthenticator(data[0], data[1]))) {
                if (ap->reply)
                        (*ap->reply)(ap, data+2, cnt-2);
        } else if (auth_debug_mode)
                printf(">>>%s: Invalid authentication in SEND: %d\r\n",
                        Name, *data);
}

void
auth_name(unsigned char *data, int cnt)
{
        unsigned char savename[256];

        if (cnt < 1) {
                if (auth_debug_mode)
                        printf(">>>%s: Empty name in NAME\r\n", Name);
                return;
        }
        if ((size_t)cnt > sizeof(savename) - 1) {
                if (auth_debug_mode)
                        printf(">>>%s: Name in NAME (%d) exceeds %d length\r\n",
                                        Name, cnt, (u_int)sizeof(savename)-1);
                return;
        }
        memmove((void *)savename, (void *)data, cnt);
        savename[cnt] = '\0';   /* Null terminate */
        if (auth_debug_mode)
                printf(">>>%s: Got NAME [%s]\r\n", Name, savename);
        auth_encrypt_user(savename);
}

int
auth_sendname(unsigned char *cp, int len)
{
        static unsigned char str_request[256+6]
                        = { IAC, SB, TELOPT_AUTHENTICATION, TELQUAL_NAME, };
        unsigned char *e = str_request + 4;
        unsigned char *ee = &str_request[sizeof(str_request)-2];

        while (--len >= 0) {
                if ((*e++ = *cp++) == IAC)
                        *e++ = IAC;
                if (e >= ee)
                        return(0);
        }
        *e++ = IAC;
        *e++ = SE;
        net_write(str_request, e - str_request);
        printsub('>', &str_request[2], e - &str_request[2]);
        return(1);
}

void
auth_finished(Authenticator *ap, int result)
{
        if (!(authenticated = ap))
                authenticated = &NoAuth;
        validuser = result;
}

/* ARGSUSED */
static void
auth_intr(int sig __unused)
{
        auth_finished(0, AUTH_REJECT);
}

int
auth_wait(char *name)
{
        if (auth_debug_mode)
                printf(">>>%s: in auth_wait.\r\n", Name);

        if (Server && !authenticating)
                return(0);

        (void) signal(SIGALRM, auth_intr);
        alarm(30);
        while (!authenticated)
                if (telnet_spin())
                        break;
        alarm(0);
        (void) signal(SIGALRM, SIG_DFL);

        /*
         * Now check to see if the user is valid or not
         */
        if (!authenticated || authenticated == &NoAuth)
                return(AUTH_REJECT);

        if (validuser == AUTH_VALID)
                validuser = AUTH_USER;

        if (authenticated->status)
                validuser = (*authenticated->status)(authenticated,
                                                     name, validuser);
        return(validuser);
}

void
auth_printsub(unsigned char *data, int cnt, unsigned char *buf, int buflen)
{
        Authenticator *ap;

        if ((ap = findauthenticator(data[1], data[2])) && ap->printsub)
                (*ap->printsub)(data, cnt, buf, buflen);
        else
                auth_gen_printsub(data, cnt, buf, buflen);
}

void
auth_gen_printsub(unsigned char *data, int cnt, unsigned char *buf, int buflen)
{
        unsigned char *cp;
        unsigned char tbuf[16];

        cnt -= 3;
        data += 3;
        buf[buflen-1] = '\0';
        buf[buflen-2] = '*';
        buflen -= 2;
        for (; cnt > 0; cnt--, data++) {
                sprintf((char *)tbuf, " %d", *data);
                for (cp = tbuf; *cp && buflen > 0; --buflen)
                        *buf++ = *cp++;
                if (buflen <= 0)
                        return;
        }
        *buf = '\0';
}
#endif