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/*
* mschap.c
*
* Version: $Id$
*
* 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
*
* Copyright 2000,2001,2006,2010 The FreeRADIUS server project
*/
/*
* This implements MS-CHAP, as described in RFC 2548
*
* http://www.freeradius.org/rfc/rfc2548.txt
*
*/
RCSID("$Id$")
#include <freeradius-devel/radiusd.h>
#include <freeradius-devel/modules.h>
#include <freeradius-devel/rad_assert.h>
#include <freeradius-devel/md5.h>
#include <freeradius-devel/sha1.h>
#include <ctype.h>
#include "smbdes.h"
#include "mschap.h"
/** Converts Unicode password to 16-byte NT hash with MD4
*
* @param[out] out Pointer to 16 byte output buffer.
* @param[in] password to encode.
* @return 0 on success else -1 on failure.
*/
int mschap_ntpwdhash(uint8_t *out, char const *password)
{
ssize_t len;
uint8_t ucs2_password[512];
len = fr_utf8_to_ucs2(ucs2_password, sizeof(ucs2_password), password, strlen(password));
if (len < 0) {
*out = '\0';
return -1;
}
fr_md4_calc(out, (uint8_t *) ucs2_password, len);
return 0;
}
/*
* challenge_hash() is used by mschap2() and auth_response()
* implements RFC2759 ChallengeHash()
* generates 64 bit challenge
*/
void mschap_challenge_hash(uint8_t const *peer_challenge,
uint8_t const *auth_challenge,
char const *user_name, uint8_t *challenge )
{
fr_sha1_ctx Context;
uint8_t hash[20];
fr_sha1_init(&Context);
fr_sha1_update(&Context, peer_challenge, 16);
fr_sha1_update(&Context, auth_challenge, 16);
fr_sha1_update(&Context, (uint8_t const *) user_name,
strlen(user_name));
fr_sha1_final(hash, &Context);
memcpy(challenge, hash, 8);
}
/*
* auth_response() generates MS-CHAP v2 SUCCESS response
* according to RFC 2759 GenerateAuthenticatorResponse()
* returns 42-octet response string
*/
void mschap_auth_response(char const *username,
uint8_t const *nt_hash_hash,
uint8_t const *ntresponse,
uint8_t const *peer_challenge, uint8_t const *auth_challenge,
char *response)
{
fr_sha1_ctx Context;
static const uint8_t magic1[39] =
{0x4D, 0x61, 0x67, 0x69, 0x63, 0x20, 0x73, 0x65, 0x72, 0x76,
0x65, 0x72, 0x20, 0x74, 0x6F, 0x20, 0x63, 0x6C, 0x69, 0x65,
0x6E, 0x74, 0x20, 0x73, 0x69, 0x67, 0x6E, 0x69, 0x6E, 0x67,
0x20, 0x63, 0x6F, 0x6E, 0x73, 0x74, 0x61, 0x6E, 0x74};
static const uint8_t magic2[41] =
{0x50, 0x61, 0x64, 0x20, 0x74, 0x6F, 0x20, 0x6D, 0x61, 0x6B,
0x65, 0x20, 0x69, 0x74, 0x20, 0x64, 0x6F, 0x20, 0x6D, 0x6F,
0x72, 0x65, 0x20, 0x74, 0x68, 0x61, 0x6E, 0x20, 0x6F, 0x6E,
0x65, 0x20, 0x69, 0x74, 0x65, 0x72, 0x61, 0x74, 0x69, 0x6F,
0x6E};
static char const hex[] = "0123456789ABCDEF";
size_t i;
uint8_t challenge[8];
uint8_t digest[20];
fr_sha1_init(&Context);
fr_sha1_update(&Context, nt_hash_hash, 16);
fr_sha1_update(&Context, ntresponse, 24);
fr_sha1_update(&Context, magic1, 39);
fr_sha1_final(digest, &Context);
mschap_challenge_hash(peer_challenge, auth_challenge, username, challenge);
fr_sha1_init(&Context);
fr_sha1_update(&Context, digest, 20);
fr_sha1_update(&Context, challenge, 8);
fr_sha1_update(&Context, magic2, 41);
fr_sha1_final(digest, &Context);
/*
* Encode the value of 'Digest' as "S=" followed by
* 40 ASCII hexadecimal digits and return it in
* AuthenticatorResponse.
* For example,
* "S=0123456789ABCDEF0123456789ABCDEF01234567"
*/
response[0] = 'S';
response[1] = '=';
/*
* The hexadecimal digits [A-F] MUST be uppercase.
*/
for (i = 0; i < sizeof(digest); i++) {
response[2 + (i * 2)] = hex[(digest[i] >> 4) & 0x0f];
response[3 + (i * 2)] = hex[digest[i] & 0x0f];
}
}
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