rlm_mschap.c

RADIUS认证协议

/*
 * rlm_mschap.c
 *
 * Version:	$Id: rlm_mschap.c,v 1.59.2.2 2005/08/24 14:37:52 nbk Exp $
 *
 *   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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Copyright 2000,2001  The FreeRADIUS server project
 */


/*
 *  mschap.c    MS-CHAP module
 *
 *  This implements MS-CHAP, as described in RFC 2548
 *
 *  http://www.freeradius.org/rfc/rfc2548.txt
 *
 */

/*
 *  If you have any questions on NTLM (Samba) passwords
 *  support, LM authentication and MS-CHAP v2 support
 *  please contact
 *
 *  Vladimir Dubrovin	[e-mail]
 *  aka
 *  ZARAZA		[e-mail]
 */

/*  MPPE support from Takahiro Wagatsuma <[e-mail]> */

#include	"autoconf.h"
#include	"libradius.h"

#include	<stdio.h>
#include	<stdlib.h>
#include    	<string.h>
#include 	<ctype.h>

#include	"radiusd.h"
#include	"modules.h"

#include        "md4.h"
#include        "md5.h"
#include	"sha1.h"
#include	"rad_assert.h"

#include	"smbdes.h"

static const char rcsid[] = "$Id: rlm_mschap.c,v 1.59.2.2 2005/08/24 14:37:52 nbk Exp $";

static const char *letters = "0123456789ABCDEF";

/*
 *	hex2bin converts hexadecimal strings into binary
 */
static int hex2bin (const char *szHex, unsigned char* szBin, int len)
{
	char * c1, * c2;
	int i;

   	for (i = 0; i < len; i++) {
		if( !(c1 = memchr(letters, toupper((int) szHex[i << 1]), 16)) ||
		    !(c2 = memchr(letters, toupper((int) szHex[(i << 1) + 1]), 16)))
		     break;
                 szBin[i] = ((c1-letters)<<4) + (c2-letters);
        }
        return i;
}

/*
 *	bin2hex creates hexadecimal presentation
 *	of binary data
 */
static void bin2hex (const unsigned char *szBin, char *szHex, int len)
{
	int i;
	for (i = 0; i < len; i++) {
		szHex[i<<1] = letters[szBin[i] >> 4];
		szHex[(i<<1) + 1] = letters[szBin[i] & 0x0F];
	}
}


/* Allowable account control bits */
#define ACB_DISABLED   0x0001  /* 1 = User account disabled */
#define ACB_HOMDIRREQ  0x0002  /* 1 = Home directory required */
#define ACB_PWNOTREQ   0x0004  /* 1 = User password not required */
#define ACB_TEMPDUP    0x0008  /* 1 = Temporary duplicate account */
#define ACB_NORMAL     0x0010  /* 1 = Normal user account */
#define ACB_MNS        0x0020  /* 1 = MNS logon user account */
#define ACB_DOMTRUST   0x0040  /* 1 = Interdomain trust account */
#define ACB_WSTRUST    0x0080  /* 1 = Workstation trust account */
#define ACB_SVRTRUST   0x0100  /* 1 = Server trust account */
#define ACB_PWNOEXP    0x0200  /* 1 = User password does not expire */
#define ACB_AUTOLOCK   0x0400  /* 1 = Account auto locked */

static int pdb_decode_acct_ctrl(const char *p)
{
	int acct_ctrl = 0;
	int finished = 0;

	/*
	 * Check if the account type bits have been encoded after the
	 * NT password (in the form [NDHTUWSLXI]).
	 */

	if (*p != '[') return 0;

	for (p++; *p && !finished; p++) {
		switch (*p) {
			case 'N': /* 'N'o password. */
			  acct_ctrl |= ACB_PWNOTREQ;
			  break;

			case 'D':  /* 'D'isabled. */
			  acct_ctrl |= ACB_DISABLED ;
			  break;

			case 'H':  /* 'H'omedir required. */
			  acct_ctrl |= ACB_HOMDIRREQ;
			  break;

			case 'T': /* 'T'emp account. */
			  acct_ctrl |= ACB_TEMPDUP;
			  break;

			case 'U': /* 'U'ser account (normal). */
			  acct_ctrl |= ACB_NORMAL;
			  break;

			case 'M': /* 'M'NS logon user account. What is this? */
			  acct_ctrl |= ACB_MNS;
			  break;

			case 'W': /* 'W'orkstation account. */
			  acct_ctrl |= ACB_WSTRUST;
			  break;

			case 'S': /* 'S'erver account. */
			  acct_ctrl |= ACB_SVRTRUST;
			  break;

			case 'L': /* 'L'ocked account. */
			  acct_ctrl |= ACB_AUTOLOCK;
			  break;

			case 'X': /* No 'X'piry on password */
			  acct_ctrl |= ACB_PWNOEXP;
			  break;

			case 'I': /* 'I'nterdomain trust account. */
			  acct_ctrl |= ACB_DOMTRUST;
			  break;

		        case ' ': /* ignore spaces */
			  break;

			case ':':
			case '\n':
			case '\0':
			case ']':
			default:
			  finished = 1;
			  break;
		}
	}

	return acct_ctrl;
}


/*
 *	ntpwdhash converts Unicode password to 16-byte NT hash
 *	with MD4
 */
static void ntpwdhash (unsigned char *szHash, const char *szPassword)
{
	char szUnicodePass[513];
	int nPasswordLen;
	int i;

	/*
	 *	NT passwords are unicode.  Convert plain text password
	 *	to unicode by inserting a zero every other byte
	 */
	nPasswordLen = strlen(szPassword);
	for (i = 0; i < nPasswordLen; i++) {
		szUnicodePass[i << 1] = szPassword[i];
		szUnicodePass[(i << 1) + 1] = 0;
	}

	/* Encrypt Unicode password to a 16-byte MD4 hash */
	md4_calc(szHash, szUnicodePass, (nPasswordLen<<1) );
}


/*
 *	challenge_hash() is used by mschap2() and auth_response()
 *	implements RFC2759 ChallengeHash()
 *	generates 64 bit challenge
 */
static void challenge_hash( const char *peer_challenge,
			    const char *auth_challenge,
			    const char *user_name, char *challenge )
{
	SHA1_CTX Context;
	unsigned char hash[20];

	SHA1Init(&Context);
	SHA1Update(&Context, peer_challenge, 16);
	SHA1Update(&Context, auth_challenge, 16);
	SHA1Update(&Context, user_name, strlen(user_name));
	SHA1Final(hash, &Context);
	memcpy(challenge, hash, 8);
}

/*
 *	auth_response() generates MS-CHAP v2 SUCCESS response
 *	according to RFC 2759 GenerateAuthenticatorResponse()
 *	returns 42-octet response string
 */
static void auth_response(const char *username,
			  const unsigned char *nt_hash_hash,
			  unsigned char *ntresponse,
			  char *peer_challenge, char *auth_challenge,
			  char *response)
{
	SHA1_CTX Context;
	const unsigned char 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};

	const unsigned char 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};

        char challenge[8];
	unsigned char digest[20];

	SHA1Init(&Context);
	SHA1Update(&Context, nt_hash_hash, 16);
	SHA1Update(&Context, ntresponse, 24);
	SHA1Update(&Context, magic1, 39);
	SHA1Final(digest, &Context);
	challenge_hash(peer_challenge, auth_challenge, username, challenge);
	SHA1Init(&Context);
	SHA1Update(&Context, digest, 20);
	SHA1Update(&Context, challenge, 8);
	SHA1Update(&Context, magic2, 41);
	SHA1Final(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] = '=';
	bin2hex(digest, response + 2, 20);
}


typedef struct rlm_mschap_t {
	int use_mppe;
	int require_encryption;
        int require_strong;
        int with_ntdomain_hack;	/* this should be in another module */
	char *passwd_file;
	char *xlat_name;
	char *auth_type;	/* I don't think this is needed... */
	char *ntlm_auth;
} rlm_mschap_t;


/*
 *	Does dynamic translation of strings.
 *
 *	Pulls NT-Response, LM-Response, or Challenge from MSCHAP
 *	attributes.
 */
static int mschap_xlat(void *instance, REQUEST *request,
		       char *fmt, char *out, size_t outlen,
		       RADIUS_ESCAPE_STRING func)
{
	int		i, data_len;
	uint8_t		*data = NULL;
	uint8_t		buffer[8];
	VALUE_PAIR	*user_name;
	VALUE_PAIR	*chap_challenge, *response;
	rlm_mschap_t	*inst = instance;

	chap_challenge = response = NULL;

	func = func;		/* -Wunused */

	/*
	 *	Challenge means MS-CHAPv1 challenge, or
	 *	hash of MS-CHAPv2 challenge, and peer challenge.
	 */
	if (strcasecmp(fmt, "Challenge") == 0) {
		chap_challenge = pairfind(request->packet->vps,
					  PW_MSCHAP_CHALLENGE);
		if (!chap_challenge) {
			DEBUG2("  rlm_mschap: No MS-CHAP-Challenge in the request.");
			return 0;
		}

		/*
		 *	MS-CHAP-Challenges are 8 octets,
		 *	for MS-CHAPv2
		 */
		if (chap_challenge->length == 8) {
			DEBUG2(" mschap1: %02x", chap_challenge->strvalue[0]);
			data = chap_challenge->strvalue;
			data_len = 8;

			/*
			 *	MS-CHAP-Challenges are 16 octets,
			 *	for MS-CHAPv2.
			 */
		} else if (chap_challenge->length == 16) {
			char *username_string;

			DEBUG2(" mschap2: %02x", chap_challenge->strvalue[0]);
			response = pairfind(request->packet->vps,
					    PW_MSCHAP2_RESPONSE);
			if (!response) {
				DEBUG2("  rlm_mschap: MS-CHAP2-Response is required to calculate MS-CHAPv1 challenge.");
				return 0;
			}

			/*
			 *	Responses are 50 octets.
			 */
			if (response->length < 50) {
				radlog(L_AUTH, "rlm_mschap: MS-CHAP-Response has the wrong format.");
				return 0;
			}

			user_name = pairfind(request->packet->vps,
					     PW_USER_NAME);
			if (!user_name) {
				DEBUG2("  rlm_mschap: User-Name is required to calculateMS-CHAPv1 Challenge.");
				return 0;
			}

			/*
			 *	with_ntdomain_hack moved here, too.
			 */
			if ((username_string = strchr(user_name->strvalue, '\\')) != NULL) {
				if (inst->with_ntdomain_hack) {
					username_string++;
				} else {
					DEBUG2("  rlm_mschap: NT Domain delimeter found, should we have enabled with_ntdomain_hack?");
					username_string = user_name->strvalue;
				}
			} else {
				username_string = user_name->strvalue;
			}

			/*
			 *	Get the MS-CHAPv1 challenge
			 *	from the MS-CHAPv2 peer challenge,
			 *	our challenge, and the user name.
			 */
			challenge_hash(response->strvalue + 2,
				       chap_challenge->strvalue,
				       username_string, buffer);
			data = buffer;
			data_len = 8;
		} else {
			DEBUG2("  rlm_mschap: Invalid MS-CHAP challenge length");
			return 0;
		}
		
		/*
		 *	Get the MS-CHAPv1 response, or the MS-CHAPv2
		 *	response.
		 */
	} else if (strcasecmp(fmt, "NT-Response") == 0) {
		response = pairfind(request->packet->vps,
				    PW_MSCHAP_RESPONSE);
		if (!response) response = pairfind(request->packet->vps,
						   PW_MSCHAP2_RESPONSE);
		if (!response) {
			DEBUG2("  rlm_mschap: No MS-CHAP-Response or MS-CHAP2-Response was found in the request.");
			return 0;
		}

		/*
		 *	For MS-CHAPv1, the NT-Response exists only
		 *	if the second octet says so.
		 */
		if ((response->attribute == PW_MSCHAP_RESPONSE) &&
		    ((response->strvalue[1] & 0x01) == 0)) {
			DEBUG2("  rlm_mschap: No NT-Response in MS-CHAP-Response");
			return 0;
		}

		/*
		 *	MS-CHAP-Response and MS-CHAP2-Response have
		 *	the NT-Response at the same offset, and are
		 *	the same length.
		 */
		data = response->strvalue + 26;
		data_len = 24;
		
		/*
		 *	LM-Response is deprecated, and exists only
		 *	in MS-CHAPv1, and not often there.
		 */
	} else if (strcasecmp(fmt, "LM-Response") == 0) {
		response = pairfind(request->packet->vps,
				    PW_MSCHAP_RESPONSE);
		if (!response) {
			DEBUG2("  rlm_mschap: No MS-CHAP-Response was found in the request.");
			return 0;
		}

		/*
		 *	For MS-CHAPv1, the NT-Response exists only
		 *	if the second octet says so.
		 */
		if ((response->strvalue[1] & 0x01) != 0) {
			DEBUG2("  rlm_mschap: No LM-Response in MS-CHAP-Response");