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rsaencpwd.c

/*-
 * 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: rsaencpwd.c,v 1.19 2002/08/12 15:09:17 joda Exp $");

#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(data, cnt, buf, buflen)
      unsigned char *data, *buf;
      int cnt, buflen;
{
      int i;

      buf[buflen-1] = '\0';         /* make sure its 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

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