408 lines
12 KiB
C
408 lines
12 KiB
C
/*
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* chap_ms.c - Microsoft MS-CHAP (NT only) 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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* $FreeBSD$
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*
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*/
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#include <ctype.h>
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#ifdef __FreeBSD__
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#include <openssl/des.h>
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#include <sha.h>
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#else
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#include <sys/types.h>
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#include <stdlib.h>
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#include <des.h>
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#include <openssl/sha.h>
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#endif
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#include <md4.h>
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#include <string.h>
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#include "chap_ms.h"
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/*
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* Documentation & specifications:
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*
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* MS-CHAP (CHAP80) rfc2433
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* MS-CHAP-V2 (CHAP81) rfc2759
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* MPPE key management draft-ietf-pppext-mppe-keys-02.txt
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*/
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static char SHA1_Pad1[40] =
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{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
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static char SHA1_Pad2[40] =
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{0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2,
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0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2,
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0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2,
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0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2, 0xF2};
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/* unused, for documentation only */
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/* only NTResp is filled in for FreeBSD */
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struct MS_ChapResponse {
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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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};
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static u_char
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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
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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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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 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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memset(ZPasswordHash, '\0', sizeof ZPasswordHash);
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memcpy(ZPasswordHash, pwHash, 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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void
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NtPasswordHash(char *key, int keylen, char *hash)
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{
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MD4_CTX MD4context;
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MD4Init(&MD4context);
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MD4Update(&MD4context, key, keylen);
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MD4Final(hash, &MD4context);
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}
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void
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HashNtPasswordHash(char *hash, char *hashhash)
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{
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MD4_CTX MD4context;
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MD4Init(&MD4context);
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MD4Update(&MD4context, hash, 16);
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MD4Final(hashhash, &MD4context);
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}
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void
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ChallengeHash(char *PeerChallenge, char *AuthenticatorChallenge,
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char *UserName, int UserNameLen, char *Challenge)
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{
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SHA_CTX Context;
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char Digest[SHA_DIGEST_LENGTH];
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char *Name;
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Name = strrchr(UserName, '\\');
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if(NULL == Name)
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Name = UserName;
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else
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Name++;
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SHA1_Init(&Context);
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SHA1_Update(&Context, PeerChallenge, 16);
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SHA1_Update(&Context, AuthenticatorChallenge, 16);
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SHA1_Update(&Context, Name, strlen(Name));
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SHA1_Final(Digest, &Context);
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memcpy(Challenge, Digest, 8);
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}
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void
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GenerateNTResponse(char *AuthenticatorChallenge, char *PeerChallenge,
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char *UserName, int UserNameLen, char *Password,
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int PasswordLen, char *Response)
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{
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char Challenge[8];
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char PasswordHash[16];
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ChallengeHash(PeerChallenge, AuthenticatorChallenge, UserName, UserNameLen,
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Challenge);
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NtPasswordHash(Password, PasswordLen, PasswordHash);
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ChallengeResponse(Challenge, PasswordHash, Response);
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}
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#ifndef __FreeBSD__
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#define LENGTH 20
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char *
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SHA1_End(SHA_CTX *ctx, char *buf)
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{
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int i;
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unsigned char digest[LENGTH];
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static const char hex[]="0123456789abcdef";
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if (!buf)
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buf = malloc(2*LENGTH + 1);
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if (!buf)
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return 0;
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SHA1_Final(digest, ctx);
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for (i = 0; i < LENGTH; i++) {
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buf[i+i] = hex[digest[i] >> 4];
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buf[i+i+1] = hex[digest[i] & 0x0f];
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}
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buf[i+i] = '\0';
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return buf;
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}
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#endif
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void
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GenerateAuthenticatorResponse(char *Password, int PasswordLen,
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char *NTResponse, char *PeerChallenge,
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char *AuthenticatorChallenge, char *UserName,
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int UserNameLen, char *AuthenticatorResponse)
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{
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SHA_CTX Context;
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char PasswordHash[16];
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char PasswordHashHash[16];
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char Challenge[8];
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u_char Digest[SHA_DIGEST_LENGTH];
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int i;
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/*
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* "Magic" constants used in response generation
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*/
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char Magic1[39] =
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{0x4D, 0x61, 0x67, 0x69, 0x63, 0x20, 0x73, 0x65, 0x72, 0x76,
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0x65, 0x72, 0x20, 0x74, 0x6F, 0x20, 0x63, 0x6C, 0x69, 0x65,
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0x6E, 0x74, 0x20, 0x73, 0x69, 0x67, 0x6E, 0x69, 0x6E, 0x67,
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0x20, 0x63, 0x6F, 0x6E, 0x73, 0x74, 0x61, 0x6E, 0x74};
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char Magic2[41] =
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{0x50, 0x61, 0x64, 0x20, 0x74, 0x6F, 0x20, 0x6D, 0x61, 0x6B,
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0x65, 0x20, 0x69, 0x74, 0x20, 0x64, 0x6F, 0x20, 0x6D, 0x6F,
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0x72, 0x65, 0x20, 0x74, 0x68, 0x61, 0x6E, 0x20, 0x6F, 0x6E,
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0x65, 0x20, 0x69, 0x74, 0x65, 0x72, 0x61, 0x74, 0x69, 0x6F,
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0x6E};
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/*
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* Hash the password with MD4
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*/
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NtPasswordHash(Password, PasswordLen, PasswordHash);
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/*
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* Now hash the hash
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*/
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HashNtPasswordHash(PasswordHash, PasswordHashHash);
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SHA1_Init(&Context);
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SHA1_Update(&Context, PasswordHashHash, 16);
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SHA1_Update(&Context, NTResponse, 24);
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SHA1_Update(&Context, Magic1, 39);
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SHA1_Final(Digest, &Context);
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ChallengeHash(PeerChallenge, AuthenticatorChallenge, UserName, UserNameLen,
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Challenge);
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SHA1_Init(&Context);
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SHA1_Update(&Context, Digest, 20);
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SHA1_Update(&Context, Challenge, 8);
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SHA1_Update(&Context, Magic2, 41);
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/*
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* Encode the value of 'Digest' as "S=" followed by
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* 40 ASCII hexadecimal digits and return it in
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* AuthenticatorResponse.
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* For example,
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* "S=0123456789ABCDEF0123456789ABCDEF01234567"
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*/
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AuthenticatorResponse[0] = 'S';
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AuthenticatorResponse[1] = '=';
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SHA1_End(&Context, AuthenticatorResponse + 2);
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for (i=2; i<42; i++)
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AuthenticatorResponse[i] = toupper(AuthenticatorResponse[i]);
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}
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void
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GetMasterKey(char *PasswordHashHash, char *NTResponse, char *MasterKey)
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{
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char Digest[SHA_DIGEST_LENGTH];
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SHA_CTX Context;
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static char Magic1[27] =
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{0x54, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x74,
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0x68, 0x65, 0x20, 0x4d, 0x50, 0x50, 0x45, 0x20, 0x4d,
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0x61, 0x73, 0x74, 0x65, 0x72, 0x20, 0x4b, 0x65, 0x79};
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SHA1_Init(&Context);
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SHA1_Update(&Context, PasswordHashHash, 16);
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SHA1_Update(&Context, NTResponse, 24);
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SHA1_Update(&Context, Magic1, 27);
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SHA1_Final(Digest, &Context);
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memcpy(MasterKey, Digest, 16);
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}
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void
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GetAsymetricStartKey(char *MasterKey, char *SessionKey, int SessionKeyLength,
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int IsSend, int IsServer)
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{
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char Digest[SHA_DIGEST_LENGTH];
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SHA_CTX Context;
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char *s;
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static char Magic2[84] =
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{0x4f, 0x6e, 0x20, 0x74, 0x68, 0x65, 0x20, 0x63, 0x6c, 0x69,
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0x65, 0x6e, 0x74, 0x20, 0x73, 0x69, 0x64, 0x65, 0x2c, 0x20,
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0x74, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x74, 0x68,
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0x65, 0x20, 0x73, 0x65, 0x6e, 0x64, 0x20, 0x6b, 0x65, 0x79,
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0x3b, 0x20, 0x6f, 0x6e, 0x20, 0x74, 0x68, 0x65, 0x20, 0x73,
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0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x73, 0x69, 0x64, 0x65,
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0x2c, 0x20, 0x69, 0x74, 0x20, 0x69, 0x73, 0x20, 0x74, 0x68,
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0x65, 0x20, 0x72, 0x65, 0x63, 0x65, 0x69, 0x76, 0x65, 0x20,
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0x6b, 0x65, 0x79, 0x2e};
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static char Magic3[84] =
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{0x4f, 0x6e, 0x20, 0x74, 0x68, 0x65, 0x20, 0x63, 0x6c, 0x69,
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0x65, 0x6e, 0x74, 0x20, 0x73, 0x69, 0x64, 0x65, 0x2c, 0x20,
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0x74, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x74, 0x68,
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0x65, 0x20, 0x72, 0x65, 0x63, 0x65, 0x69, 0x76, 0x65, 0x20,
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0x6b, 0x65, 0x79, 0x3b, 0x20, 0x6f, 0x6e, 0x20, 0x74, 0x68,
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0x65, 0x20, 0x73, 0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x73,
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0x69, 0x64, 0x65, 0x2c, 0x20, 0x69, 0x74, 0x20, 0x69, 0x73,
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0x20, 0x74, 0x68, 0x65, 0x20, 0x73, 0x65, 0x6e, 0x64, 0x20,
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0x6b, 0x65, 0x79, 0x2e};
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if (IsSend) {
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if (IsServer) {
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s = Magic3;
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} else {
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s = Magic2;
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}
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} else {
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if (IsServer) {
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s = Magic2;
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} else {
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s = Magic3;
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}
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}
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SHA1_Init(&Context);
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SHA1_Update(&Context, MasterKey, 16);
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SHA1_Update(&Context, SHA1_Pad1, 40);
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SHA1_Update(&Context, s, 84);
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SHA1_Update(&Context, SHA1_Pad2, 40);
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SHA1_Final(Digest, &Context);
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memcpy(SessionKey, Digest, SessionKeyLength);
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}
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void
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GetNewKeyFromSHA(char *StartKey, char *SessionKey, long SessionKeyLength,
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char *InterimKey)
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{
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SHA_CTX Context;
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char Digest[SHA_DIGEST_LENGTH];
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SHA1_Init(&Context);
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SHA1_Update(&Context, StartKey, SessionKeyLength);
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SHA1_Update(&Context, SHA1_Pad1, 40);
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SHA1_Update(&Context, SessionKey, SessionKeyLength);
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SHA1_Update(&Context, SHA1_Pad2, 40);
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SHA1_Final(Digest, &Context);
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memcpy(InterimKey, Digest, SessionKeyLength);
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}
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#if 0
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static void
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Get_Key(char *InitialSessionKey, char *CurrentSessionKey,
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int LengthOfDesiredKey)
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{
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SHA_CTX Context;
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char Digest[SHA_DIGEST_LENGTH];
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SHA1_Init(&Context);
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SHA1_Update(&Context, InitialSessionKey, LengthOfDesiredKey);
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SHA1_Update(&Context, SHA1_Pad1, 40);
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SHA1_Update(&Context, CurrentSessionKey, LengthOfDesiredKey);
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SHA1_Update(&Context, SHA1_Pad2, 40);
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SHA1_Final(Digest, &Context);
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memcpy(CurrentSessionKey, Digest, LengthOfDesiredKey);
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}
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#endif
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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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mschap_NT(char *passwordHash, char *challenge)
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{
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u_char response[24];
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ChallengeResponse(challenge, passwordHash, response);
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memcpy(passwordHash, response, 24);
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passwordHash[24] = 1; /* NT-style response */
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}
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void
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mschap_LANMan(char *digest, char *challenge, char *secret)
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{
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static u_char salt[] = "KGS!@#$%"; /* RASAPI32.dll */
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char SECRET[14], *ptr, *end;
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u_char hash[16];
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end = SECRET + sizeof SECRET;
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for (ptr = SECRET; *secret && ptr < end; ptr++, secret++)
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*ptr = toupper(*secret);
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if (ptr < end)
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memset(ptr, '\0', end - ptr);
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DesEncrypt(salt, SECRET, hash);
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DesEncrypt(salt, SECRET + 7, hash + 8);
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ChallengeResponse(challenge, hash, digest);
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}
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