334 lines
9.1 KiB
C
334 lines
9.1 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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/*
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* Modifications by Lauri Pesonen / lpesonen@clinet.fi, april 1997
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*
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* Implemented LANManager type password response to MS-CHAP challenges.
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* Now pppd provides both NT style and LANMan style blocks, and the
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* prefered is set by option "ms-lanman". Default is to use NT.
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* The hash text (StdText) was taken from Win95 RASAPI32.DLL.
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*
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* You should also use DOMAIN\\USERNAME as described in README.MSCHAP80
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*/
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#ifndef lint
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static char rcsid[] = "$Id: chap_ms.c,v 1.3 1997/08/19 17:52:35 peter Exp $";
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#endif
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#ifdef CHAPMS
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#include <stdio.h>
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#include <string.h>
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#include <ctype.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 <unistd.h>
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#include "pppd.h"
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#include "chap.h"
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#include "chap_ms.h"
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#include "md4.h"
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#ifndef USE_CRYPT
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#include <des.h>
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#endif
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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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/* We use MS_CHAP_RESPONSE_LEN, rather than sizeof(MS_ChapResponse),
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in case this struct gets padded. */
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static void ChallengeResponse __P((u_char *, u_char *, u_char *));
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static void DesEncrypt __P((u_char *, u_char *, u_char *));
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static void MakeKey __P((u_char *, u_char *));
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static u_char Get7Bits __P((u_char *, int));
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static void ChapMS_NT __P((char *, int, char *, int, MS_ChapResponse *));
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#ifdef MSLANMAN
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static void ChapMS_LANMan __P((char *, int, char *, int, MS_ChapResponse *));
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#endif
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#ifdef USE_CRYPT
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static void Expand __P((u_char *, u_char *));
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static void Collapse __P((u_char *, u_char *));
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#endif
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static void
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ChallengeResponse(challenge, pwHash, response)
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u_char *challenge; /* IN 8 octets */
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u_char *pwHash; /* IN 16 octets */
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u_char *response; /* OUT 24 octets */
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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, MD4_SIGNATURE_SIZE);
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#if 0
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log_packet(ZPasswordHash, sizeof(ZPasswordHash), "ChallengeResponse - ZPasswordHash", LOG_DEBUG);
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#endif
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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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#if 0
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log_packet(response, 24, "ChallengeResponse - response", LOG_DEBUG);
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#endif
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}
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#ifdef USE_CRYPT
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static void
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DesEncrypt(clear, key, cipher)
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u_char *clear; /* IN 8 octets */
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u_char *key; /* IN 7 octets */
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u_char *cipher; /* OUT 8 octets */
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{
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u_char des_key[8];
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u_char crypt_key[66];
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u_char des_input[66];
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MakeKey(key, des_key);
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Expand(des_key, crypt_key);
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setkey(crypt_key);
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#if 0
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CHAPDEBUG((LOG_INFO, "DesEncrypt: 8 octet input : %02X%02X%02X%02X%02X%02X%02X%02X",
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clear[0], clear[1], clear[2], clear[3], clear[4], clear[5], clear[6], clear[7]));
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#endif
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Expand(clear, des_input);
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encrypt(des_input, 0);
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Collapse(des_input, cipher);
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#if 0
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CHAPDEBUG((LOG_INFO, "DesEncrypt: 8 octet output: %02X%02X%02X%02X%02X%02X%02X%02X",
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cipher[0], cipher[1], cipher[2], cipher[3], cipher[4], cipher[5], cipher[6], cipher[7]));
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#endif
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}
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#else /* USE_CRYPT */
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static void
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DesEncrypt(clear, key, cipher)
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u_char *clear; /* IN 8 octets */
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u_char *key; /* IN 7 octets */
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u_char *cipher; /* OUT 8 octets */
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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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#if 0
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CHAPDEBUG((LOG_INFO, "DesEncrypt: 8 octet input : %02X%02X%02X%02X%02X%02X%02X%02X",
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clear[0], clear[1], clear[2], clear[3], clear[4], clear[5], clear[6], clear[7]));
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#endif
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des_ecb_encrypt((des_cblock *)clear, (des_cblock *)cipher, key_schedule, 1);
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#if 0
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CHAPDEBUG((LOG_INFO, "DesEncrypt: 8 octet output: %02X%02X%02X%02X%02X%02X%02X%02X",
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cipher[0], cipher[1], cipher[2], cipher[3], cipher[4], cipher[5], cipher[6], cipher[7]));
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#endif
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}
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#endif /* USE_CRYPT */
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static u_char Get7Bits(input, startBit)
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u_char *input;
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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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#ifdef USE_CRYPT
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/* in == 8-byte string (expanded version of the 56-bit key)
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* out == 64-byte string where each byte is either 1 or 0
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* Note that the low-order "bit" is always ignored by by setkey()
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*/
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static void Expand(in, out)
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u_char *in;
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u_char *out;
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{
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int j, c;
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int i;
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for(i = 0; i < 64; in++){
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c = *in;
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for(j = 7; j >= 0; j--)
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*out++ = (c >> j) & 01;
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i += 8;
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}
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}
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/* The inverse of Expand
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*/
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static void Collapse(in, out)
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u_char *in;
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u_char *out;
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{
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int j;
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int i;
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unsigned int c;
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for (i = 0; i < 64; i += 8, out++) {
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c = 0;
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for (j = 7; j >= 0; j--, in++)
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c |= *in << j;
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*out = c & 0xff;
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}
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}
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#endif
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static void MakeKey(key, des_key)
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u_char *key; /* IN 56 bit DES key missing parity bits */
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u_char *des_key; /* OUT 64 bit DES key with parity bits added */
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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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#ifndef USE_CRYPT
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des_set_odd_parity((des_cblock *)des_key);
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#endif
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#if 0
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CHAPDEBUG((LOG_INFO, "MakeKey: 56-bit input : %02X%02X%02X%02X%02X%02X%02X",
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key[0], key[1], key[2], key[3], key[4], key[5], key[6]));
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CHAPDEBUG((LOG_INFO, "MakeKey: 64-bit output: %02X%02X%02X%02X%02X%02X%02X%02X",
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des_key[0], des_key[1], des_key[2], des_key[3], des_key[4], des_key[5], des_key[6], des_key[7]));
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#endif
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}
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static void
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ChapMS_NT(rchallenge, rchallenge_len, secret, secret_len, response)
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char *rchallenge;
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int rchallenge_len;
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char *secret;
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int secret_len;
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MS_ChapResponse *response;
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{
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int i;
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MD4_CTX md4Context;
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u_char hash[MD4_SIGNATURE_SIZE];
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u_char unicodePassword[MAX_NT_PASSWORD * 2];
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static int low_byte_first = -1;
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/* Initialize the Unicode version of the secret (== password). */
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/* This implicitly supports 8-bit ISO8859/1 characters. */
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BZERO(unicodePassword, sizeof(unicodePassword));
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for (i = 0; i < secret_len; i++)
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unicodePassword[i * 2] = (u_char)secret[i];
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MD4Init(&md4Context);
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MD4Update(&md4Context, unicodePassword, secret_len * 2 * 8); /* Unicode is 2 bytes/char, *8 for bit count */
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MD4Final(hash, &md4Context); /* Tell MD4 we're done */
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ChallengeResponse(rchallenge, hash, response->NTResp);
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}
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#ifdef MSLANMAN
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static u_char *StdText = (u_char *)"KGS!@#$%"; /* key from rasapi32.dll */
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static void
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ChapMS_LANMan(rchallenge, rchallenge_len, secret, secret_len, response)
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char *rchallenge;
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int rchallenge_len;
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char *secret;
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int secret_len;
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MS_ChapResponse *response;
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{
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int i;
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u_char UcasePassword[MAX_NT_PASSWORD]; /* max is actually 14 */
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u_char PasswordHash[MD4_SIGNATURE_SIZE];
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/* LANMan password is case insensitive */
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BZERO(UcasePassword, sizeof(UcasePassword));
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for (i = 0; i < secret_len; i++)
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UcasePassword[i] = (u_char)toupper(secret[i]);
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DesEncrypt( StdText, UcasePassword + 0, PasswordHash + 0 );
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DesEncrypt( StdText, UcasePassword + 7, PasswordHash + 8 );
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ChallengeResponse(rchallenge, PasswordHash, response->LANManResp);
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}
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#endif
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void
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ChapMS(cstate, rchallenge, rchallenge_len, secret, secret_len)
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chap_state *cstate;
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char *rchallenge;
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int rchallenge_len;
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char *secret;
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int secret_len;
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{
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MS_ChapResponse response;
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#ifdef MSLANMAN
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extern int ms_lanman;
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#endif
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#if 0
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CHAPDEBUG((LOG_INFO, "ChapMS: secret is '%.*s'", secret_len, secret));
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#endif
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BZERO(&response, sizeof(response));
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/* Calculate both always */
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ChapMS_NT(rchallenge, rchallenge_len, secret, secret_len, &response);
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#ifdef MSLANMAN
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ChapMS_LANMan(rchallenge, rchallenge_len, secret, secret_len, &response);
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/* prefered method is set by option */
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response.UseNT = !ms_lanman;
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#else
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response.UseNT = 1;
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#endif
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BCOPY(&response, cstate->response, MS_CHAP_RESPONSE_LEN);
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cstate->resp_length = MS_CHAP_RESPONSE_LEN;
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}
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#endif /* CHAPMS */
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