rlm_mschap.c

RADIUS 服务器介绍 RADIUS服务器支持标准的RADIUS协议

/*
 * rlm_mschap.c	
 *
 * Version:	$Id: rlm_mschap.c,v 1.41 2003/07/07 19:08:09 aland 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"

#define PW_MSCHAP_RESPONSE	((311 << 16) | 1)
#define PW_MSCHAP_CHALLENGE	((311 << 16) | 11)
#define PW_MSCHAP2_RESPONSE	((311 << 16) | 25)

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 (char *szHash, const char *szPassword)
{
	char szUnicodePass[513];
	char 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;
	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);
}

static void mschap2(const char *peer_challenge, const char *auth_challenge,
		    const char *user_name, const char *nt_password,
		    char *response)
{
	char challenge[8];
	
	challenge_hash(peer_challenge, auth_challenge, user_name,
		       challenge);

	lrad_mschap(nt_password, challenge, response);
}

/*
 *	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 char *nt_password,
			  char *ntresponse,
			  char *peer_challenge, char *auth_challenge,
			  char *response)
{
	SHA1_CTX Context;
	char hashhash[16];
	const 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 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];
        char digest[20];

	/*
	 * Hash password hash into hashhash
	 */

	md4_calc(hashhash, nt_password, 16);

	SHA1Init(&Context);
	SHA1Update(&Context, hashhash, 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);
}

struct mschap_instance {
	int use_mppe;
	int require_encryption;
	int require_strong;
	char *passwd_file;
	char *auth_type;
};

static CONF_PARSER module_config[] = {
	/*
	 *	Cache the password by default.
	 */
	{ "use_mppe",    PW_TYPE_BOOLEAN,
	  offsetof(struct mschap_instance,use_mppe), NULL, "yes" },
	{ "require_encryption",    PW_TYPE_BOOLEAN,
	  offsetof(struct mschap_instance,require_encryption), NULL, "no" },
	{ "require_strong",    PW_TYPE_BOOLEAN,
	  offsetof(struct mschap_instance,require_strong), NULL, "no" },
	{ "passwd",   PW_TYPE_STRING_PTR,
	  offsetof(struct mschap_instance, passwd_file), NULL,  NULL },
	{ "authtype",   PW_TYPE_STRING_PTR,
	  offsetof(struct mschap_instance, auth_type), NULL,  NULL },
	
	{ NULL, -1, 0, NULL, NULL }		/* end the list */
};

/*
 *	deinstantiate module, free all memory allocated during
 *	mschap_instantiate()
 */
static int mschap_detach(void *instance){
#define inst ((struct mschap_instance *)instance)
	if (inst->passwd_file) free(inst->passwd_file);
	if (inst->auth_type) free(inst->auth_type);
	free(instance);
	return 0;
#undef inst
}
	
/*
 *	Create instance for our module. Allocate space for
 *	instance structure and read configuration parameters
 */
static int mschap_instantiate(CONF_SECTION *conf, void **instance)
{
	struct mschap_instance *inst;

	inst = *instance = rad_malloc(sizeof(*inst));
	if (!inst) {
		return -1;
	}
	memset(inst, 0, sizeof(*inst));

	if (cf_section_parse(conf, inst, module_config) < 0) {
		free(inst);
		return -1;
	}

	/*
	 *	This module used to support SMB Password files, but it
	 *	made it too complicated.  If the user tries to
	 *	configure an SMB Password file, then die, with an
	 *	error message.
	 */
	if (inst->passwd_file) {
		radlog(L_ERR, "rlm_mschap: SMB password file is no longer supported in this module.  Use rlm_passwd module instead");
		mschap_detach(inst);
		return -1;
	}

	return 0;
}

/*
 *	add_reply() adds either MS-CHAP2-Success or MS-CHAP-Error
 *	attribute to reply packet
 */
static void add_reply(VALUE_PAIR** vp, unsigned char ident,
		      const char* name, const char* value, int len)
{
	VALUE_PAIR *reply_attr;
	reply_attr = pairmake(name, "", T_OP_EQ);
	if (!reply_attr) {
		DEBUG("  rlm_mschap: Failed to create attribute %s: %s\n", name, librad_errstr);
		return;
	}

	reply_attr->strvalue[0] = ident;
	memcpy(reply_attr->strvalue + 1, value, len);
	reply_attr->length = len + 1;
	pairadd(vp, reply_attr);
}

/*
 *	Add MPPE attributes to the reply.
 */
static void mppe_add_reply(VALUE_PAIR** vp,
			   const char* name, const char* value, int len)
{
       VALUE_PAIR *reply_attr;
       reply_attr = pairmake(name, "", T_OP_EQ);
       if (!reply_attr) {
	       DEBUG("rlm_mschap: mppe_add_reply failed to create attribute %s: %s\n", name, librad_errstr);
	       return;
       }

       memcpy(reply_attr->strvalue, value, len);
       reply_attr->length = len;
       pairadd(vp, reply_attr);
}

static const uint8_t SHSpad1[40] =
               { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };

static const uint8_t SHSpad2[40] =
               { 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
                 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
                 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
                 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2 };

static const uint8_t magic1[27] =
               { 0x54, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x74,
                 0x68, 0x65, 0x20, 0x4d, 0x50, 0x50, 0x45, 0x20, 0x4d,
                 0x61, 0x73, 0x74, 0x65, 0x72, 0x20, 0x4b, 0x65, 0x79 };

static const uint8_t magic2[84] =
               { 0x4f, 0x6e, 0x20, 0x74, 0x68, 0x65, 0x20, 0x63, 0x6c, 0x69,
                 0x65, 0x6e, 0x74, 0x20, 0x73, 0x69, 0x64, 0x65, 0x2c, 0x20,
                 0x74, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x74, 0x68,
                 0x65, 0x20, 0x73, 0x65, 0x6e, 0x64, 0x20, 0x6b, 0x65, 0x79,
                 0x3b, 0x20, 0x6f, 0x6e, 0x20, 0x74, 0x68, 0x65, 0x20, 0x73,
                 0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x73, 0x69, 0x64, 0x65,
                 0x2c, 0x20, 0x69, 0x74, 0x20, 0x69, 0x73, 0x20, 0x74, 0x68,
                 0x65, 0x20, 0x72, 0x65, 0x63, 0x65, 0x69, 0x76, 0x65, 0x20,
                 0x6b, 0x65, 0x79, 0x2e };

static const uint8_t magic3[84] =
               { 0x4f, 0x6e, 0x20, 0x74, 0x68, 0x65, 0x20, 0x63, 0x6c, 0x69,
                 0x65, 0x6e, 0x74, 0x20, 0x73, 0x69, 0x64, 0x65, 0x2c, 0x20,
                 0x74, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x74, 0x68,
                 0x65, 0x20, 0x72, 0x65, 0x63, 0x65, 0x69, 0x76, 0x65, 0x20,
                 0x6b, 0x65, 0x79, 0x3b, 0x20, 0x6f, 0x6e, 0x20, 0x74, 0x68,
                 0x65, 0x20, 0x73, 0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x73,
                 0x69, 0x64, 0x65, 0x2c, 0x20, 0x69, 0x74, 0x20, 0x69, 0x73,
                 0x20, 0x74, 0x68, 0x65, 0x20, 0x73, 0x65, 0x6e, 0x64, 0x20,
                 0x6b, 0x65, 0x79, 0x2e };


static void mppe_GetMasterKey(uint8_t *nt_hashhash,uint8_t *nt_response,
			      uint8_t *masterkey)
{
       uint8_t digest[20];
       SHA1_CTX Context;

       SHA1Init(&Context);
       SHA1Update(&Context,nt_hashhash,16);
       SHA1Update(&Context,nt_response,24);
       SHA1Update(&Context,magic1,27);
       SHA1Final(digest,&Context);

       memcpy(masterkey,digest,16);
}


static void mppe_GetAsymmetricStartKey(uint8_t *masterkey,uint8_t *sesskey,
				       int keylen,int issend)
{
       uint8_t digest[20];
       const uint8_t *s;
       SHA1_CTX Context;

       memset(digest,0,20);

       if(issend) {
               s = magic3;
       } else {
               s = magic2;
       }

       SHA1Init(&Context);
       SHA1Update(&Context,masterkey,16);
       SHA1Update(&Context,SHSpad1,40);
       SHA1Update(&Context,s,84);
       SHA1Update(&Context,SHSpad2,40);
       SHA1Final(digest,&Context);

       memcpy(sesskey,digest,keylen);
}