/*-
 * Copyright (c) 1992, 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. 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.
 */

#include <config.h>

RCSID("$Id$");

#ifdef  RSA_ENCPWD
/*
 * COPYRIGHT (C) 1990 DIGITAL EQUIPMENT CORPORATION
 * ALL RIGHTS RESERVED
 *
 * "Digital Equipment Corporation authorizes the reproduction,
 * distribution and modification of this software subject to the following
 * restrictions:
 *
 * 1.  Any partial or whole copy of this software, or any modification
 * thereof, must include this copyright notice in its entirety.
 *
 * 2.  This software is supplied "as is" with no warranty of any kind,
 * expressed or implied, for any purpose, including any warranty of fitness
 * or merchantibility.  DIGITAL assumes no responsibility for the use or
 * reliability of this software, nor promises to provide any form of
 * support for it on any basis.
 *
 * 3.  Distribution of this software is authorized only if no profit or
 * remuneration of any kind is received in exchange for such distribution.
 *
 * 4.  This software produces public key authentication certificates
 * bearing an expiration date established by DIGITAL and RSA Data
 * Security, Inc.  It may cease to generate certificates after the expiration
 * date.  Any modification of this software that changes or defeats
 * the expiration date or its effect is unauthorized.
 *
 * 5.  Software that will renew or extend the expiration date of
 * authentication certificates produced by this software may be obtained
 * from RSA Data Security, Inc., 10 Twin Dolphin Drive, Redwood City, CA
 * 94065, (415)595-8782, or from DIGITAL"
 *
 */

#include <sys/types.h>
#ifdef HAVE_ARPA_TELNET_H
#include <arpa/telnet.h>
#endif
#include <pwd.h>
#include <stdio.h>

#include <stdlib.h>
#include <string.h>
#ifdef SOCKS
#include <socks.h>
#endif

#include "encrypt.h"
#include "auth.h"
#include "misc.h"
#include "cdc.h"

extern auth_debug_mode;

static unsigned char str_data[1024] = { IAC, SB, TELOPT_AUTHENTICATION, 0,
                                        AUTHTYPE_RSA_ENCPWD, };
static unsigned char str_name[1024] = { IAC, SB, TELOPT_AUTHENTICATION,
                                        TELQUAL_NAME, };

#define RSA_ENCPWD_AUTH 0       /* Authentication data follows */
#define RSA_ENCPWD_REJECT       1       /* Rejected (reason might follow) */
#define RSA_ENCPWD_ACCEPT       2       /* Accepted */
#define RSA_ENCPWD_CHALLENGEKEY 3       /* Challenge and public key */

#define NAME_SZ   40
#define CHAL_SZ   20
#define PWD_SZ    40

static  KTEXT_ST auth;
static  char name[NAME_SZ];
static  char user_passwd[PWD_SZ];
static  char key_file[2*NAME_SZ];
static  char lhostname[NAME_SZ];
static char  challenge[CHAL_SZ];
static int   challenge_len;

        static int
Data(ap, type, d, c)
        Authenticator *ap;
        int type;
        void *d;
        int c;
{
        unsigned char *p = str_data + 4;
        unsigned char *cd = (unsigned char *)d;

        if (c == -1)
                c = strlen((char *)cd);

        if (0) {
                printf("%s:%d: [%d] (%d)",
                        str_data[3] == TELQUAL_IS ? ">>>IS" : ">>>REPLY",
                        str_data[3],
                        type, c);
                printd(d, c);
                printf("\r\n");
        }
        *p++ = ap->type;
        *p++ = ap->way;
        if (type != NULL) *p++ = type;
        while (c-- > 0) {
                if ((*p++ = *cd++) == IAC)
                        *p++ = IAC;
        }
        *p++ = IAC;
        *p++ = SE;
        if (str_data[3] == TELQUAL_IS)
                printsub('>', &str_data[2], p - (&str_data[2]));
        return(telnet_net_write(str_data, p - str_data));
}

        int
rsaencpwd_init(ap, server)
        Authenticator *ap;
        int server;
{
        char  *cp;
        FILE  *fp;

        if (server) {
                str_data[3] = TELQUAL_REPLY;
                memset(key_file, 0, sizeof(key_file));
                gethostname(lhostname, sizeof(lhostname));
                if ((cp = strchr(lhostname, '.')) != 0)  *cp = '\0';
                snprintf(key_file, sizeof(key_file),
                         SYSCONFDIR "/.%s_privkey", lhostname);
                if ((fp=fopen(key_file, "r"))==NULL) return(0);
                fclose(fp);
        } else {
                str_data[3] = TELQUAL_IS;
        }
        return(1);
}

        int
rsaencpwd_send(ap)
        Authenticator *ap;
{

        printf("[ Trying RSAENCPWD ... ]\r\n");
        if (!UserNameRequested) {
                return(0);
        }
        if (!auth_sendname(UserNameRequested, strlen(UserNameRequested))) {
                return(0);
        }
        if (!Data(ap, NULL, NULL, 0)) {
                return(0);
        }


        return(1);
}

        void
rsaencpwd_is(ap, data, cnt)
        Authenticator *ap;
        unsigned char *data;
        int cnt;
{
        Session_Key skey;
        des_cblock datablock;
        char  r_passwd[PWD_SZ], r_user[NAME_SZ];
        char  *cp, key[160];
        char  chalkey[160], *ptr;
        FILE  *fp;
        int r, i, j, chalkey_len, len;
        time_t now;

        cnt--;
        switch (*data++) {
        case RSA_ENCPWD_AUTH:
                memmove(auth.dat, data, auth.length = cnt);

                if ((fp=fopen(key_file, "r"))==NULL) {
                  Data(ap, RSA_ENCPWD_REJECT, "Auth failed", -1);
                  auth_finished(ap, AUTH_REJECT);
                  return;
                }
                /*
                 *  get privkey
                 */
                fscanf(fp, "%x;", &len);
                for (i=0;i<len;i++) {
                  j = getc(fp);  key[i]=j;
                }
                fclose(fp);

                r = accept_rsa_encpwd(&auth, key, challenge,
                                      challenge_len, r_passwd);
                if (r < 0) {
                  Data(ap, RSA_ENCPWD_REJECT, "Auth failed", -1);
                  auth_finished(ap, AUTH_REJECT);
                  return;
                }
                auth_encrypt_userpwd(r_passwd);
                if (rsaencpwd_passwdok(UserNameRequested, UserPassword) == 0) {
                  /*
                   *  illegal username and password
                   */
                  Data(ap, RSA_ENCPWD_REJECT, "Illegal password", -1);
                  auth_finished(ap, AUTH_REJECT);
                  return;
                }

                Data(ap, RSA_ENCPWD_ACCEPT, 0, 0);
                auth_finished(ap, AUTH_USER);
                break;


        case IAC:

                /*
                 * If we are doing mutual authentication, get set up to send
                 * the challenge, and verify it when the response comes back.
                 */
                if ((ap->way & AUTH_HOW_MASK) == AUTH_HOW_ONE_WAY) {
                  int i;


                  time(&now);
                  if ((now % 2) == 0) {
                    snprintf(challenge, sizeof(challenge), "%x", now);
                    challenge_len = strlen(challenge);
                  } else {
                    strlcpy(challenge, "randchal", sizeof(challenge));
                    challenge_len = 8;
                  }

                  if ((fp=fopen(key_file, "r"))==NULL) {
                    Data(ap, RSA_ENCPWD_REJECT, "Auth failed", -1);
                    auth_finished(ap, AUTH_REJECT);
                    return;
                  }
                  /*
                   *  skip privkey
                   */
                  fscanf(fp, "%x;", &len);
                  for (i=0;i<len;i++) {
                    j = getc(fp);
                  }
                  /*
                   * get pubkey
                   */
                  fscanf(fp, "%x;", &len);
                  for (i=0;i<len;i++) {
                    j = getc(fp);  key[i]=j;
                  }
                  fclose(fp);
                  chalkey[0] = 0x30;
                  ptr = (char *) &chalkey[1];
                  chalkey_len = 1+NumEncodeLengthOctets(i)+i+1+NumEncodeLengthOctets(challenge_len)+challenge_len;
                  EncodeLength(ptr, chalkey_len);
                  ptr +=NumEncodeLengthOctets(chalkey_len);
                  *ptr++ = 0x04;  /* OCTET STRING */
                  *ptr++ = challenge_len;
                  memmove(ptr, challenge, challenge_len);
                  ptr += challenge_len;
                  *ptr++ = 0x04;  /* OCTET STRING */
                  EncodeLength(ptr, i);
                  ptr += NumEncodeLengthOctets(i);
                  memmove(ptr, key, i);
                  chalkey_len = 1+NumEncodeLengthOctets(chalkey_len)+chalkey_len;
                  Data(ap, RSA_ENCPWD_CHALLENGEKEY, chalkey, chalkey_len);
                }
                break;

        default:
                Data(ap, RSA_ENCPWD_REJECT, 0, 0);
                break;
        }
}


        void
rsaencpwd_reply(ap, data, cnt)
        Authenticator *ap;
        unsigned char *data;
        int cnt;
{
        Session_Key skey;
        KTEXT_ST token;
        des_cblock enckey;
        int r, pubkey_len;
        char    randchal[CHAL_SZ], *cp;
        char    chalkey[160], pubkey[128], *ptr;

        if (cnt-- < 1)
                return;
        switch (*data++) {
        case RSA_ENCPWD_REJECT:
                if (cnt > 0) {
                        printf("[ RSA_ENCPWD refuses authentication because %.*s ]\r\n",
                                cnt, data);
                } else
                        printf("[ RSA_ENCPWD refuses authentication ]\r\n");
                auth_send_retry();
                return;
        case RSA_ENCPWD_ACCEPT:
                printf("[ RSA_ENCPWD accepts you ]\r\n");
                auth_finished(ap, AUTH_USER);
                return;
        case RSA_ENCPWD_CHALLENGEKEY:
                /*
                 * Verify that the response to the challenge is correct.
                 */

                memmove(chalkey, data, cnt);
                ptr = (char *) &chalkey[0];
                ptr += DecodeHeaderLength(chalkey);
                if (*ptr != 0x04) {
                  return;
                }
                *ptr++;
                challenge_len = DecodeValueLength(ptr);
                ptr += NumEncodeLengthOctets(challenge_len);
                memmove(challenge, ptr, challenge_len);
                ptr += challenge_len;
                if (*ptr != 0x04) {
                  return;
                }
                *ptr++;
                pubkey_len = DecodeValueLength(ptr);
                ptr += NumEncodeLengthOctets(pubkey_len);
                memmove(pubkey, ptr, pubkey_len);
                memset(user_passwd, 0, sizeof(user_passwd));
                des_read_pw_string(user_passwd, sizeof(user_passwd)-1, "Password: ", 0);
                UserPassword = user_passwd;
                Challenge = challenge;
                r = init_rsa_encpwd(&token, user_passwd, challenge, challenge_len, pubkey);
                if (r < 0) {
                  token.length = 1;
                }

                if (!Data(ap, RSA_ENCPWD_AUTH, token.dat, token.length)) {
                  return;
                }

                break;

        default:
                return;
        }
}

        int
rsaencpwd_status(ap, name, name_sz, level)
        Authenticator *ap;
        char *name;
        size_t name_sz;
        int level;
{

        if (level < AUTH_USER)
                return(level);

        if (UserNameRequested && rsaencpwd_passwdok(UserNameRequested, UserPassword)) {
                strlcpy(name, UserNameRequested, name_sz);
                return(AUTH_VALID);
        } else {
                return(AUTH_USER);
        }
}

#define BUMP(buf, len)          while (*(buf)) {++(buf), --(len);}
#define ADDC(buf, len, c)       if ((len) > 0) {*(buf)++ = (c); --(len);}

        void
rsaencpwd_printsub(unsigned char *data, size_t cnt,
                   unsigned char * buf, size_t buflen)
{
        size_t i;

        buf[buflen-1] = '\0';           /* make sure it's NULL terminated */
        buflen -= 1;

        switch(data[3]) {
        case RSA_ENCPWD_REJECT: /* Rejected (reason might follow) */
                strlcpy((char *)buf, " REJECT ", buflen);
                goto common;

        case RSA_ENCPWD_ACCEPT: /* Accepted (name might follow) */
                strlcpy((char *)buf, " ACCEPT ", buflen);
        common:
                BUMP(buf, buflen);
                if (cnt <= 4)
                        break;
                ADDC(buf, buflen, '"');
                for (i = 4; i < cnt; i++)
                        ADDC(buf, buflen, data[i]);
                ADDC(buf, buflen, '"');
                ADDC(buf, buflen, '\0');
                break;

        case RSA_ENCPWD_AUTH:           /* Authentication data follows */
                strlcpy((char *)buf, " AUTH", buflen);
                goto common2;

        case RSA_ENCPWD_CHALLENGEKEY:
                strlcpy((char *)buf, " CHALLENGEKEY", buflen);
                goto common2;

        default:
                snprintf(buf, buflen, " %d (unknown)", data[3]);
        common2:
                BUMP(buf, buflen);
                for (i = 4; i < cnt; i++) {
                        snprintf(buf, buflen, " %d", data[i]);
                        BUMP(buf, buflen);
                }
                break;
        }
}

int rsaencpwd_passwdok(name, passwd)
char *name, *passwd;
{
  char *crypt();
  char *salt, *p;
  struct passwd *pwd;
  int   passwdok_status = 0;

  if (pwd = k_getpwnam(name))
    salt = pwd->pw_passwd;
  else salt = "xx";

  p = crypt(passwd, salt);

  if (pwd && !strcmp(p, pwd->pw_passwd)) {
    passwdok_status = 1;
  } else passwdok_status = 0;
  return(passwdok_status);
}

#endif

#ifdef notdef

prkey(msg, key)
        char *msg;
        unsigned char *key;
{
        int i;
        printf("%s:", msg);
        for (i = 0; i < 8; i++)
                printf(" %3d", key[i]);
        printf("\r\n");
}
#endif