110 lines
3.2 KiB
C
110 lines
3.2 KiB
C
/*
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* chap_ms.c - Microsoft MS-CHAP compatible implementation.
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*
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* Copyright (c) 1995 Eric Rosenquist, Strata Software Limited.
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* http://www.strataware.com/
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*
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms are permitted
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* provided that the above copyright notice and this paragraph are
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* duplicated in all such forms and that any documentation,
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* advertising materials, and other materials related to such
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* distribution and use acknowledge that the software was developed
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* by Eric Rosenquist. The name of the author may not be used to
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* endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
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* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*/
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#include <stdio.h>
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#include <sys/types.h>
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#include <sys/time.h>
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#include <syslog.h>
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#include <string.h>
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#include "chap.h"
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#include "chap_ms.h"
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#include <des.h>
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/* unused, for documentation only */
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/* only NTResp is filled in for FreeBSD */
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typedef struct {
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u_char LANManResp[24];
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u_char NTResp[24];
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u_char UseNT; /* If 1, ignore the LANMan response field */
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} MS_ChapResponse;
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static void DesEncrypt(u_char *, u_char *, u_char *);
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static void MakeKey(u_char *, u_char *);
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static void /* IN 8 octets IN 16 octets OUT 24 octets */
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ChallengeResponse(u_char* challenge, u_char* pwHash, u_char* response)
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{
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char ZPasswordHash[21];
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bzero(ZPasswordHash, sizeof(ZPasswordHash));
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bcopy(pwHash, ZPasswordHash, 16);
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DesEncrypt(challenge, ZPasswordHash + 0, response + 0);
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DesEncrypt(challenge, ZPasswordHash + 7, response + 8);
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DesEncrypt(challenge, ZPasswordHash + 14, response + 16);
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}
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static void /* IN 8 octets IN 7 octest OUT 8 octets */
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DesEncrypt(u_char* clear, u_char* key, u_char* cipher)
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{
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des_cblock des_key;
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des_key_schedule key_schedule;
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MakeKey(key, des_key);
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des_set_key(&des_key, key_schedule);
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des_ecb_encrypt((des_cblock *)clear, (des_cblock *)cipher, key_schedule, 1);
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}
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static u_char Get7Bits(u_char* input, int startBit)
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{
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register unsigned int word;
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word = (unsigned)input[startBit / 8] << 8;
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word |= (unsigned)input[startBit / 8 + 1];
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word >>= 15 - (startBit % 8 + 7);
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return word & 0xFE;
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}
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/* IN 56 bit DES key missing parity bits
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OUT 64 bit DES key with parity bits added */
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static void MakeKey(u_char* key, u_char* des_key)
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{
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des_key[0] = Get7Bits(key, 0);
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des_key[1] = Get7Bits(key, 7);
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des_key[2] = Get7Bits(key, 14);
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des_key[3] = Get7Bits(key, 21);
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des_key[4] = Get7Bits(key, 28);
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des_key[5] = Get7Bits(key, 35);
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des_key[6] = Get7Bits(key, 42);
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des_key[7] = Get7Bits(key, 49);
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des_set_odd_parity((des_cblock *)des_key);
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}
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/* passwordHash 16-bytes MD4 hashed password
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challenge 8-bytes peer CHAP challenge
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since passwordHash is in a 24-byte buffer, response is written in there */
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void
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ChapMS(char* passwordHash, char* challenge, int challenge_len)
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{
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u_char response[24];
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ChallengeResponse(challenge, passwordHash, response);
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bcopy(response, passwordHash, 24);
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passwordHash += 24;
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*passwordHash = 1;
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}
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