ttlsphase2.cpp

source_code 实现无线局域网中的802.1x功能

/**************************************************************************/
/* WIRE1x Version 1.0: A client-side 802.1x implementation                */
/* based on xsupplicant of Open1x for Windows XP, 2000, 98, and Me        */
/*                                                                        */
/* This code is released under both the GPL version 2 and BSD licenses.   */
/* Either license may be used.  The respective licenses are found below.  */
/*                                                                        */
/* Copyright (C) 2004, WIRE Lab, National Tsing Hua Univ., Hsinchu, Taiwan*/
/* All Rights Reserved                                                    */
/**************************************************************************/
/*
 * --- GPL Version 2 License ---
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * --- BSD License ---
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *  - Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
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 *    notice, this list of conditions and the following disclaimer in the
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 *       This product includes software developed by the University of
 *       Maryland at College Park and its contributors.
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 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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#include <stdafx.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <stdio.h>
#include <ctype.h>
#include <assert.h>
#include <winsock.h>
#include <openssl/ssl.h>

#include "eapcrypt.h"
#include "userconf.h"
#include "ttlsphase2.h"
#include "eapmschapv2.h"
#ifndef TTLS_PHASE2_DEBUG
#define TTLS_PHASE2_DEBUG  0
#endif
//*********************************************
//for uint32_t
typedef unsigned int uint32_t;
//for uint8_t
typedef unsigned char uint8_t;
//not sure
typedef unsigned long uint64_t;
//**********************************************
// A few numbers from the radius dictionary. 8-)
#define USER_NAME_AVP        1
#define USER_PASSWORD_AVP    2
#define CHAP_PASSWORD_AVP    3
#define CHAP_CHALLENGE_AVP   60

// Defines for MS-CHAP values also from the dictionary.
#define MS_VENDOR_ATTR       311
#define MS_CHAP_RESPONSE     1
#define MS_CHAP_CHALLENGE    11
#define MS_CHAP2_RESPONSE    25

#define MANDITORY_FLAG       0x40
#define VENDOR_FLAG          0x80
#define TTLS_CHALLENGE       "ttls challenge"    // Need to generate implied challenge.
#define TTLS_CHALLENGE_SIZE  14

uint32_t avp_code;
uint32_t bitmask_avp_len;

// If we add a new phase 2 type, it needs to be defined here.
char *phase2_auth_types[] = {
  "PAP",
  "CHAP",
  "MSCHAP",
  "MSCHAPV2",
  NULL
};

void (*phase2_method[])(char *, int *) = {
  ttls_do_pap,
  ttls_do_chap,
  ttls_do_mschap,
  ttls_do_mschapv2
};


// This is from section 10.1 of the TTLS RFC.
char *implicit_challenge()
{
  return (char *)eapcrypt_gen_keyblock((u_char *)TTLS_CHALLENGE, TTLS_CHALLENGE_SIZE);
}

void build_avp(uint32_t avp_value, uint32_t avp_vendor, uint64_t avp_flags, uint8_t *in_value, uint64_t in_value_len, uint8_t *out_value, int *out_size)
{
  int avp_padded;
  uint32_t avp_vendor_stuff;

  avp_code = htonl(avp_value);
  avp_vendor_stuff = htonl(avp_vendor);

  if (avp_vendor != 0) 
    {
      in_value_len = in_value_len +4;
    }

  if ((in_value_len % 4) != 0)
    {
      avp_padded = (in_value_len + (4 - (in_value_len % 4)));
    } else {
      avp_padded = in_value_len;
    }
  bitmask_avp_len = htonl((avp_flags << 24) + in_value_len + 8);

  memset(out_value, 0, avp_padded+12);
  memcpy(&out_value[0], &avp_code, 4);
  memcpy(&out_value[4], &bitmask_avp_len, 4);
  if (avp_vendor != 0)
    {
      memcpy(&out_value[8], &avp_vendor_stuff, 4);
      memcpy(&out_value[12], in_value, in_value_len);
      *out_size = avp_padded+8;
    } else {
      memcpy(&out_value[8], in_value, in_value_len);
      *out_size = avp_padded+8;
    }
}


void ttls_do_mschapv2(char *out_data, int *out_size)
{
  u_char mschap_challenge[16], mschap_answer[50];
  u_char mschap_result[24];
  char *username = NULL, *password = NULL, *challenge = NULL;
  int avp_offset, avp_out_size, username_size, id;

  username = get_phase2id();
  username_size = strlen(username);

  // Send the Username AVP
  build_avp(USER_NAME_AVP, 0, MANDITORY_FLAG, (u_char *)username, username_size, (u_char *)out_data, &avp_out_size);

  avp_offset = avp_out_size;

  challenge = implicit_challenge();

  memcpy(&mschap_challenge, challenge, 16);
  id = challenge[17];

  // Send the MS-CHAP AVP
  build_avp(MS_CHAP_CHALLENGE, MS_VENDOR_ATTR, (MANDITORY_FLAG | VENDOR_FLAG), (u_char *)&mschap_challenge, 16, (u_char *)&out_data[avp_offset], &avp_out_size);

  avp_offset+=avp_out_size;

  memset(&mschap_answer, 0, 50);
  memcpy(&mschap_answer, &mschap_challenge, 16);

  // The first 24 bytes should be left as 0s.
  password = get_password();    // Get our password.

  GenerateNTResponse((char *)&mschap_challenge, (char *)&mschap_challenge, username, password, (char *)&mschap_result);

  mschap_answer[0] = id;
  mschap_answer[1] = 0;
  memcpy(&mschap_answer[2], &mschap_challenge, 16);
  memcpy(&mschap_answer[26], &mschap_result, 24);

  build_avp(MS_CHAP2_RESPONSE, MS_VENDOR_ATTR, (MANDITORY_FLAG | VENDOR_FLAG), (u_char *)&mschap_answer, 50, (u_char *)&out_data[avp_offset], &avp_out_size);
  avp_offset+=avp_out_size;
  *out_size = avp_offset;

  if (username != NULL)
    {
      free(username);
      username = NULL;
    }

  if (password != NULL)
    {
      free(password);
      password = NULL;
    }
}


// For phase 2 MS-CHAP, we get 8 bytes implicit challenge, and 1 byte for ID.
void ttls_do_mschap(char *out_data, int *out_size)
{
  u_char mschap_challenge[8], mschap_answer[49];
  u_char mschap_result[24];
  char *username = NULL, *password = NULL, *challenge = NULL;
  int avp_offset, avp_out_size, username_size, id;

  username = get_phase2id();
  username_size = strlen(username);

  // Send the Username AVP
  build_avp(USER_NAME_AVP, 0, MANDITORY_FLAG, (u_char *)username, username_size, (u_char *)out_data, &avp_out_size);

  avp_offset = avp_out_size;

  challenge = implicit_challenge();

  memcpy((char *)&mschap_challenge[0], challenge, 8);
  id = challenge[9];

  // Send the MS-CHAP AVP
  build_avp(MS_CHAP_CHALLENGE, MS_VENDOR_ATTR, (MANDITORY_FLAG | VENDOR_FLAG), (u_char *)&mschap_challenge, 8, (u_char *)&out_data[avp_offset], &avp_out_size);

  avp_offset+=avp_out_size;

  memset((char *)&mschap_answer[0], 0, 49);
  password = get_password();    // Get our password.

  NtChallengeResponse((char *)&mschap_challenge, password, (char *)&mschap_result);

  mschap_answer[0] = id;
  mschap_answer[1] = 1; // Use NT Style Passwords.
  memcpy((char *)&mschap_answer[26], (char *)&mschap_result, 24);

  build_avp(MS_CHAP_RESPONSE, MS_VENDOR_ATTR, (MANDITORY_FLAG | VENDOR_FLAG), (u_char *)&mschap_answer, 50, (u_char *)&out_data[avp_offset], &avp_out_size);
  avp_offset+=avp_out_size;

  *out_size = avp_offset;
  if (username != NULL)
    {
      free(username);
      username = NULL;
    }

  if (password != NULL)
    {
      free(password);
      password = NULL;
    }
}

// For phase 2 CHAP, we need to get an implicit_challenge from the phase 1,
// and use the first 16 bytes for challenge, and the 17th byte as the ID.
// Then, to find the CHAP password hash, we find MD5(id + password + 
// challenge).  Then, we need to send 3 AVPs back to the authenticator.
// The username, challenge, and password AVPs.  Where the challenge is the
// 16 bytes from the implicit challenge.  
void ttls_do_chap(char *out_data, int *out_size)
{
  u_char *challenge = NULL, *tohash = NULL;
  u_char *user_passwd = NULL;
  u_char chap_challenge[18], chap_hash[17];
  uint8_t session_id;
  int username_size, avp_out_size;
  int avp_offset, md5_length, hashlen;
  EVP_MD_CTX *ctx=NULL;
  char *username = NULL;

  username = get_phase2id();
  username_size = strlen(username);
  build_avp(USER_NAME_AVP, 0, MANDITORY_FLAG, (u_char *)username, username_size, (u_char *)out_data, &avp_out_size);

  avp_offset = avp_out_size;

  // Get the implicit challenge.
  challenge = (u_char *)implicit_challenge();
  assert(challenge != NULL);

  memcpy(&chap_challenge, challenge, 16);
  session_id = challenge[16];

  // Build the password hash.
  ctx = (EVP_MD_CTX *)malloc(sizeof(EVP_MD_CTX));
  if (ctx == NULL)
    {
      return;
    }

  user_passwd = (u_char *)get_password();

  if(username!=NULL)
    {
      free(username);
      username = NULL;
    }

  tohash = (u_char *)malloc(1+16+strlen((char *)user_passwd));
  if (tohash == NULL)
    {
      return;
    }

  tohash[0] = session_id;
  memcpy(&tohash[1], user_passwd, strlen((char *)user_passwd));
  memcpy(&tohash[1+strlen((char *)user_passwd)], &chap_challenge, 16);
  hashlen = 1+strlen((char *)user_passwd)+16;
  free(user_passwd);   // We are done with it.
  user_passwd = NULL;
  
  EVP_DigestInit(ctx, EVP_md5());
  EVP_DigestUpdate(ctx, tohash, hashlen);
  EVP_DigestFinal(ctx, (u_char *)&chap_hash[1], (uint32_t *)&md5_length);
  
  if (md5_length != 16)  // We didn't get back a valid hash!
    {
    }
  chap_hash[0]=session_id;

  build_avp(CHAP_PASSWORD_AVP, 0, MANDITORY_FLAG, (u_char *)chap_hash, 17, (u_char *)&out_data[avp_offset], &avp_out_size);

  avp_offset += avp_out_size;

  build_avp(CHAP_CHALLENGE_AVP, 0, MANDITORY_FLAG, (u_char *)&chap_challenge, 16, (u_char *)&out_data[avp_offset], &avp_out_size);

  if (tohash != NULL)
    {
      free(tohash);
      tohash = NULL;
    }

  if (ctx != NULL)
    {
      free(ctx);
      ctx = NULL;
    }

  if (user_passwd != NULL) free(user_passwd);

  *out_size = avp_offset+avp_out_size;
}

void ttls_do_pap(char *out_data, int *out_size)
{
  char *username, *password, *tempbuf;
  int username_size, passwd_size, avp_out_size, avp_offset;

  // Get the username from our configuration.  (We should probably change this
  // to allow a different username in phase 2... But, for now use the phase
  // one name.)
  username = get_phase2id();

  password = get_password();
  avp_offset = 0;

  username_size = strlen(username);
  build_avp(USER_NAME_AVP, 0, MANDITORY_FLAG, (u_char *)username, username_size, (u_char *)out_data, &avp_out_size);

  avp_offset += avp_out_size;

  // We have the username AVP loaded, so it's time to build the password AVP.
  passwd_size = (strlen(password) + (16-(strlen(password) % 16)));

  tempbuf = (char *)malloc(passwd_size);
  if (tempbuf == NULL)
    {
      return;
    }

  memset(tempbuf, 0, passwd_size);
  memcpy(tempbuf, password, strlen(password));

  build_avp(USER_PASSWORD_AVP, 0, MANDITORY_FLAG, (u_char *)tempbuf, passwd_size, (u_char *)&out_data[avp_offset], &avp_out_size);

  *out_size = avp_offset + avp_out_size;
  
  if (password != NULL) 
    {
      free(password);
      password=NULL;
    }

  if (username != NULL)
    {
      free(username);
      username=NULL;
    }

  if (tempbuf != NULL)
    {
      free(tempbuf);
      tempbuf = NULL;
    }

}

// We don't do anything with the "in" stuff for now..
void ttls_do_phase2(char *in, int in_size, char *out, int *out_size)
{
  int i;
  char *phase2name=NULL;

  // We need to see what phase 2 method we should use.
  // First, make sure that the method name is in all caps.
  phase2name = get_phase2auth();

  if (phase2name != NULL)
    {
      for (i=0;i<strlen(phase2name);i++)
	{
	  phase2name[i] = toupper(phase2name[i]);
	}

      i = 0;
      while ((phase2_auth_types[i]!=NULL) && (strncmp(phase2name, phase2_auth_types[i], strlen(phase2name)) != 0))
	{
	  i++;
	}

      if (phase2_auth_types[i] == NULL)
	{
	  ttls_do_pap(out, out_size);
	} else {
	  (*phase2_method[i])(out, out_size);
	}
    } else {
      ttls_do_pap(out, out_size);
    }


  if (phase2name != NULL) 
    {
      free(phase2name);
      phase2name = NULL;
    }


}