/*
* chap_ms.c - Microsoft MS-CHAP compatible implementation.
*
* Copyright (c) 1995 Eric Rosenquist, Strata Software Limited.
* http://www.strataware.com/
*
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* advertising materials, and other materials related to such
* distribution and use acknowledge that the software was developed
* by Eric Rosenquist. The name of the author may not be used to
* endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
/*
* Modifications by Lauri Pesonen / lpesonen@clinet.fi, april 1997
*
* Implemented LANManager type password response to MS-CHAP challenges.
* Now pppd provides both NT style and LANMan style blocks, and the
* prefered is set by option "ms-lanman". Default is to use NT.
* The hash text (StdText) was taken from Win95 RASAPI32.DLL.
*
* You should also use DOMAIN\\USERNAME as described in README.MSCHAP80
*/
#define RCSID "$Id$"
#ifdef CHAPMS
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <sys/types.h>
#include <sys/time.h>
#include <unistd.h>
#ifdef HAVE_CRYPT_H
#include <crypt.h>
#endif
#include "pppd.h"
#include "chap.h"
#include "chap_ms.h"
#include "md4.h"
#ifndef USE_CRYPT
#include <des.h>
#endif
static const char rcsid[] = RCSID;
typedef struct {
u_char LANManResp[24];
u_char NTResp[24];
u_char UseNT; /* If 1, ignore the LANMan response field */
} MS_ChapResponse;
/* We use MS_CHAP_RESPONSE_LEN, rather than sizeof(MS_ChapResponse),
in case this struct gets padded. */
static void ChallengeResponse __P((u_char *, u_char *, u_char *));
static void DesEncrypt __P((u_char *, u_char *, u_char *));
static void MakeKey __P((u_char *, u_char *));
static u_char Get7Bits __P((u_char *, int));
static void ChapMS_NT __P((char *, int, char *, int, MS_ChapResponse *));
#ifdef MSLANMAN
static void ChapMS_LANMan __P((char *, int, char *, int, MS_ChapResponse *));
#endif
#ifdef USE_CRYPT
static void Expand __P((u_char *, u_char *));
static void Collapse __P((u_char *, u_char *));
#endif
#ifdef MSLANMAN
bool ms_lanman = 0; /* Use LanMan password instead of NT */
/* Has meaning only with MS-CHAP challenges */
#endif
static void
ChallengeResponse(challenge, pwHash, response)
u_char *challenge; /* IN 8 octets */
u_char *pwHash; /* IN 16 octets */
u_char *response; /* OUT 24 octets */
{
char ZPasswordHash[21];
BZERO(ZPasswordHash, sizeof(ZPasswordHash));
BCOPY(pwHash, ZPasswordHash, MD4_SIGNATURE_SIZE);
#if 0
dbglog("ChallengeResponse - ZPasswordHash %.*B",
sizeof(ZPasswordHash), ZPasswordHash);
#endif
DesEncrypt(challenge, ZPasswordHash + 0, response + 0);
DesEncrypt(challenge, ZPasswordHash + 7, response + 8);
DesEncrypt(challenge, ZPasswordHash + 14, response + 16);
#if 0
dbglog("ChallengeResponse - response %.24B", response);
#endif
}
#ifdef USE_CRYPT
static void
DesEncrypt(clear, key, cipher)
u_char *clear; /* IN 8 octets */
u_char *key; /* IN 7 octets */
u_char *cipher; /* OUT 8 octets */
{
u_char des_key[8];
u_char crypt_key[66];
u_char des_input[66];
MakeKey(key, des_key);
Expand(des_key, crypt_key);
setkey(crypt_key);
#if 0
CHAPDEBUG((LOG_INFO, "DesEncrypt: 8 octet input : %.8B", clear));
#endif
Expand(clear, des_input);
encrypt(des_input, 0);
Collapse(des_input, cipher);
#if 0
CHAPDEBUG((LOG_INFO, "DesEncrypt: 8 octet output: %.8B", cipher));
#endif
}
#else /* USE_CRYPT */
static void
DesEncrypt(clear, key, cipher)
u_char *clear; /* IN 8 octets */
u_char *key; /* IN 7 octets */
u_char *cipher; /* OUT 8 octets */
{
des_cblock des_key;
des_key_schedule key_schedule;
MakeKey(key, des_key);
des_set_key(&des_key, key_schedule);
#if 0
CHAPDEBUG((LOG_INFO, "DesEncrypt: 8 octet input : %.8B", clear));
#endif
des_ecb_encrypt((des_cblock *)clear, (des_cblock *)cipher, key_schedule, 1);
#if 0
CHAPDEBUG((LOG_INFO, "DesEncrypt: 8 octet output: %.8B", cipher));
#endif
}
#endif /* USE_CRYPT */
static u_char Get7Bits(input, startBit)
u_char *input;
int startBit;
{
register unsigned int word;
word = (unsigned)input[startBit / 8] << 8;
word |= (unsigned)input[startBit / 8 + 1];
word >>= 15 - (startBit % 8 + 7);
return word & 0xFE;
}
#ifdef USE_CRYPT
/* in == 8-byte string (expanded version of the 56-bit key)
* out == 64-byte string where each byte is either 1 or 0
* Note that the low-order "bit" is always ignored by by setkey()
*/
static void Expand(in, out)
u_char *in;
u_char *out;
{
int j, c;
int i;
for(i = 0; i < 64; in++){
c = *in;
for(j = 7; j >= 0; j--)
*out++ = (c >> j) & 01;
i += 8;
}
}
/* The inverse of Expand
*/
static void Collapse(in, out)
u_char *in;
u_char *out;
{
int j;
int i;
unsigned int c;
for (i = 0; i < 64; i += 8, out++) {
c = 0;
for (j = 7; j >= 0; j--, in++)
c |= *in << j;
*out = c & 0xff;
}
}
#endif
static void MakeKey(key, des_key)
u_char *key; /* IN 56 bit DES key missing parity bits */
u_char *des_key; /* OUT 64 bit DES key with parity bits added */
{
des_key[0] = Get7Bits(key, 0);
des_key[1] = Get7Bits(key, 7);
des_key[2] = Get7Bits(key, 14);
des_key[3] = Get7Bits(key, 21);
des_key[4] = Get7Bits(key, 28);
des_key[5] = Get7Bits(key, 35);
des_key[6] = Get7Bits(key, 42);
des_key[7] = Get7Bits(key, 49);
#ifndef USE_CRYPT
des_set_odd_parity((des_cblock *)des_key);
#endif
#if 0
CHAPDEBUG((LOG_INFO, "MakeKey: 56-bit input : %.7B", key));
CHAPDEBUG((LOG_INFO, "MakeKey: 64-bit output: %.8B", des_key));
#endif
}
static void
ChapMS_NT(rchallenge, rchallenge_len, secret, secret_len, response)
char *rchallenge;
int rchallenge_len;
char *secret;
int secret_len;
MS_ChapResponse *response;
{
int i;
#ifdef __NetBSD__
/* NetBSD uses the libc md4 routines which take bytes instead of bits */
int mdlen = secret_len * 2;
#else
int mdlen = secret_len * 2 * 8;
#endif
MD4_CTX md4Context;
u_char hash[MD4_SIGNATURE_SIZE];
u_char unicodePassword[MAX_NT_PASSWORD * 2];
/* Initialize the Unicode version of the secret (== password). */
/* This implicitly supports 8-bit ISO8859/1 characters. */
BZERO(unicodePassword, sizeof(unicodePassword));
for (i = 0; i < secret_len; i++)
unicodePassword[i * 2] = (u_char)secret[i];
MD4Init(&md4Context);
MD4Update(&md4Context, unicodePassword, mdlen);
MD4Final(hash, &md4Context); /* Tell MD4 we're done */
ChallengeResponse(rchallenge, hash, response->NTResp);
}
#ifdef MSLANMAN
static u_char *StdText = (u_char *)"KGS!@#$%"; /* key from rasapi32.dll */
static void
ChapMS_LANMan(rchallenge, rchallenge_len, secret, secret_len, response)
char *rchallenge;
int rchallenge_len;
char *secret;
int secret_len;
MS_ChapResponse *response;
{
int i;
u_char UcasePassword[MAX_NT_PASSWORD]; /* max is actually 14 */
u_char PasswordHash[MD4_SIGNATURE_SIZE];
/* LANMan password is case insensitive */
BZERO(UcasePassword, sizeof(UcasePassword));
for (i = 0; i < secret_len; i++)
UcasePassword[i] = (u_char)toupper(secret[i]);
DesEncrypt( StdText, UcasePassword + 0, PasswordHash + 0 );
DesEncrypt( StdText, UcasePassword + 7, PasswordHash + 8 );
ChallengeResponse(rchallenge, PasswordHash, response->LANManResp);
}
#endif
void
ChapMS(cstate, rchallenge, rchallenge_len, secret, secret_len)
chap_state *cstate;
char *rchallenge;
int rchallenge_len;
char *secret;
int secret_len;
{
MS_ChapResponse response;
#if 0
CHAPDEBUG((LOG_INFO, "ChapMS: secret is '%.*s'", secret_len, secret));
#endif
BZERO(&response, sizeof(response));
/* Calculate both always */
ChapMS_NT(rchallenge, rchallenge_len, secret, secret_len, &response);
#ifdef MSLANMAN
ChapMS_LANMan(rchallenge, rchallenge_len, secret, secret_len, &response);
/* prefered method is set by option */
response.UseNT = !ms_lanman;
#else
response.UseNT = 1;
#endif
BCOPY(&response, cstate->response, MS_CHAP_RESPONSE_LEN);
cstate->resp_length = MS_CHAP_RESPONSE_LEN;
}
#endif /* CHAPMS */
