From Marco D'Itri.

[mpls-ppp.git] / pppd / chap_ms.c

/*
 * chap_ms.c - Microsoft MS-CHAP compatible implementation.
 *
 * Copyright (c) 1995 Eric Rosenquist.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The name(s) of the authors of this software must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission.
 *
 * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
 * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

/*
 * 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
 */

/*
 * Modifications by Frank Cusack, frank@google.com, March 2002.
 *
 *   Implemented MS-CHAPv2 functionality, heavily based on sample
 *   implementation in RFC 2759.  Implemented MPPE functionality,
 *   heavily based on sample implementation in RFC 3079.
 *
 * Copyright (c) 2002 Google, Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The name(s) of the authors of this software must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission.
 *
 * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
 * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 */

#define RCSID   "$Id: chap_ms.c,v 1.34 2004/11/15 22:13:26 paulus Exp $"

#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>

#include "pppd.h"
#include "chap-new.h"
#include "chap_ms.h"
#include "md4.h"
#include "sha1.h"
#include "pppcrypt.h"
#include "magic.h"

static const char rcsid[] = RCSID;


static void     ascii2unicode __P((char[], int, u_char[]));
static void     NTPasswordHash __P((char *, int, u_char[MD4_SIGNATURE_SIZE]));
static void     ChallengeResponse __P((u_char *, u_char *, u_char[24]));
static void     ChapMS_NT __P((u_char *, char *, int, u_char[24]));
static void     ChapMS2_NT __P((u_char *, u_char[16], char *, char *, int,
                                u_char[24]));
static void     GenerateAuthenticatorResponsePlain
                        __P((char*, int, u_char[24], u_char[16], u_char *,
                             char *, u_char[41]));
#ifdef MSLANMAN
static void     ChapMS_LANMan __P((u_char *, char *, int, u_char *));
#endif

#ifdef MPPE
static void     Set_Start_Key __P((u_char *, char *, int));
static void     SetMasterKeys __P((char *, int, u_char[24], int));
#endif

#ifdef MSLANMAN
bool    ms_lanman = 0;          /* Use LanMan password instead of NT */
                                /* Has meaning only with MS-CHAP challenges */
#endif

#ifdef MPPE
u_char mppe_send_key[MPPE_MAX_KEY_LEN];
u_char mppe_recv_key[MPPE_MAX_KEY_LEN];
int mppe_keys_set = 0;          /* Have the MPPE keys been set? */

#ifdef DEBUGMPPEKEY
/* For MPPE debug */
/* Use "[]|}{?/><,`!2&&(" (sans quotes) for RFC 3079 MS-CHAPv2 test value */
static char *mschap_challenge = NULL;
/* Use "!@\#$%^&*()_+:3|~" (sans quotes, backslash is to escape #) for ... */
static char *mschap2_peer_challenge = NULL;
#endif

#include "fsm.h"                /* Need to poke MPPE options */
#include "ccp.h"
#include <net/ppp-comp.h>
#endif

/*
 * Command-line options.
 */
static option_t chapms_option_list[] = {
#ifdef MSLANMAN
        { "ms-lanman", o_bool, &ms_lanman,
          "Use LanMan passwd when using MS-CHAP", 1 },
#endif
#ifdef DEBUGMPPEKEY
        { "mschap-challenge", o_string, &mschap_challenge,
          "specify CHAP challenge" },
        { "mschap2-peer-challenge", o_string, &mschap2_peer_challenge,
          "specify CHAP peer challenge" },
#endif
        { NULL }
};

/*
 * chapms_generate_challenge - generate a challenge for MS-CHAP.
 * For MS-CHAP the challenge length is fixed at 8 bytes.
 * The length goes in challenge[0] and the actual challenge starts
 * at challenge[1].
 */
static void
chapms_generate_challenge(unsigned char *challenge)
{
        *challenge++ = 8;
#ifdef DEBUGMPPEKEY
        if (mschap_challenge && strlen(mschap_challenge) == 8)
                memcpy(challenge, mschap_challenge, 8);
        else
#endif
                random_bytes(challenge, 8);
}

static void
chapms2_generate_challenge(unsigned char *challenge)
{
        *challenge++ = 16;
#ifdef DEBUGMPPEKEY
        if (mschap_challenge && strlen(mschap_challenge) == 16)
                memcpy(challenge, mschap_challenge, 16);
        else
#endif
                random_bytes(challenge, 16);
}

static int
chapms_verify_response(int id, char *name,
                       unsigned char *secret, int secret_len,
                       unsigned char *challenge, unsigned char *response,
                       char *message, int message_space)
{
        unsigned char md[MS_CHAP_RESPONSE_LEN];
        int diff;
        int challenge_len, response_len;

        challenge_len = *challenge++;   /* skip length, is 8 */
        response_len = *response++;
        if (response_len != MS_CHAP_RESPONSE_LEN)
                goto bad;

#ifndef MSLANMAN
        if (!response[MS_CHAP_USENT]) {
                /* Should really propagate this into the error packet. */
                notice("Peer request for LANMAN auth not supported");
                goto bad;
        }
#endif

        /* Generate the expected response. */
        ChapMS(challenge, (char *)secret, secret_len, md);

#ifdef MSLANMAN
        /* Determine which part of response to verify against */
        if (!response[MS_CHAP_USENT])
                diff = memcmp(&response[MS_CHAP_LANMANRESP],
                              &md[MS_CHAP_LANMANRESP], MS_CHAP_LANMANRESP_LEN);
        else
#endif
                diff = memcmp(&response[MS_CHAP_NTRESP], &md[MS_CHAP_NTRESP],
                              MS_CHAP_NTRESP_LEN);

        if (diff == 0) {
                slprintf(message, message_space, "Access granted");
                return 1;
        }

 bad:
        /* See comments below for MS-CHAP V2 */
        slprintf(message, message_space, "E=691 R=1 C=%0.*B V=0",
                 challenge_len, challenge);
        return 0;
}

static int
chapms2_verify_response(int id, char *name,
                        unsigned char *secret, int secret_len,
                        unsigned char *challenge, unsigned char *response,
                        char *message, int message_space)
{
        unsigned char md[MS_CHAP2_RESPONSE_LEN];
        char saresponse[MS_AUTH_RESPONSE_LENGTH+1];
        int challenge_len, response_len;

        challenge_len = *challenge++;   /* skip length, is 16 */
        response_len = *response++;
        if (response_len != MS_CHAP2_RESPONSE_LEN)
                goto bad;       /* not even the right length */

        /* Generate the expected response and our mutual auth. */
        ChapMS2(challenge, &response[MS_CHAP2_PEER_CHALLENGE], name,
                (char *)secret, secret_len, md,
                (unsigned char *)saresponse, MS_CHAP2_AUTHENTICATOR);

        /* compare MDs and send the appropriate status */
        /*
         * Per RFC 2759, success message must be formatted as
         *     "S=<auth_string> M=<message>"
         * where
         *     <auth_string> is the Authenticator Response (mutual auth)
         *     <message> is a text message
         *
         * However, some versions of Windows (win98 tested) do not know
         * about the M=<message> part (required per RFC 2759) and flag
         * it as an error (reported incorrectly as an encryption error
         * to the user).  Since the RFC requires it, and it can be
         * useful information, we supply it if the peer is a conforming
         * system.  Luckily (?), win98 sets the Flags field to 0x04
         * (contrary to RFC requirements) so we can use that to
         * distinguish between conforming and non-conforming systems.
         *
         * Special thanks to Alex Swiridov <say@real.kharkov.ua> for
         * help debugging this.
         */
        if (memcmp(&md[MS_CHAP2_NTRESP], &response[MS_CHAP2_NTRESP],
                   MS_CHAP2_NTRESP_LEN) == 0) {
                if (response[MS_CHAP2_FLAGS])
                        slprintf(message, message_space, "S=%s", saresponse);
                else
                        slprintf(message, message_space, "S=%s M=%s",
                                 saresponse, "Access granted");
                return 1;
        }

 bad:
        /*
         * Failure message must be formatted as
         *     "E=e R=r C=c V=v M=m"
         * where
         *     e = error code (we use 691, ERROR_AUTHENTICATION_FAILURE)
         *     r = retry (we use 1, ok to retry)
         *     c = challenge to use for next response, we reuse previous
         *     v = Change Password version supported, we use 0
         *     m = text message
         *
         * The M=m part is only for MS-CHAPv2.  Neither win2k nor
         * win98 (others untested) display the message to the user anyway.
         * They also both ignore the E=e code.
         *
         * Note that it's safe to reuse the same challenge as we don't
         * actually accept another response based on the error message
         * (and no clients try to resend a response anyway).
         *
         * Basically, this whole bit is useless code, even the small
         * implementation here is only because of overspecification.
         */
        slprintf(message, message_space, "E=691 R=1 C=%0.*B V=0 M=%s",
                 challenge_len, challenge, "Access denied");
        return 0;
}

static void
chapms_make_response(unsigned char *response, int id, char *our_name,
                     unsigned char *challenge, char *secret, int secret_len,
                     unsigned char *private)
{
        challenge++;    /* skip length, should be 8 */
        *response++ = MS_CHAP_RESPONSE_LEN;
        ChapMS(challenge, secret, secret_len, response);
}

static void
chapms2_make_response(unsigned char *response, int id, char *our_name,
                      unsigned char *challenge, char *secret, int secret_len,
                      unsigned char *private)
{
        challenge++;    /* skip length, should be 16 */
        *response++ = MS_CHAP2_RESPONSE_LEN;
        ChapMS2(challenge,
#ifdef DEBUGMPPEKEY
                mschap2_peer_challenge,
#else
                NULL,
#endif
                our_name, secret, secret_len, response, private,
                MS_CHAP2_AUTHENTICATEE);
}

static int
chapms2_check_success(unsigned char *msg, int len, unsigned char *private)
{
        if ((len < MS_AUTH_RESPONSE_LENGTH + 2) ||
            strncmp((char *)msg, "S=", 2) != 0) {
                /* Packet does not start with "S=" */
                error("MS-CHAPv2 Success packet is badly formed.");
                return 0;
        }
        msg += 2;
        len -= 2;
        if (len < MS_AUTH_RESPONSE_LENGTH
            || memcmp(msg, private, MS_AUTH_RESPONSE_LENGTH)) {
                /* Authenticator Response did not match expected. */
                error("MS-CHAPv2 mutual authentication failed.");
                return 0;
        }
        /* Authenticator Response matches. */
        msg += MS_AUTH_RESPONSE_LENGTH; /* Eat it */
        len -= MS_AUTH_RESPONSE_LENGTH;
        if ((len >= 3) && !strncmp((char *)msg, " M=", 3)) {
                msg += 3; /* Eat the delimiter */
        } else if (len) {
                /* Packet has extra text which does not begin " M=" */
                error("MS-CHAPv2 Success packet is badly formed.");
                return 0;
        }
        return 1;
}

static void
chapms_handle_failure(unsigned char *inp, int len)
{
        int err;
        char *p, *msg;

        /* We want a null-terminated string for strxxx(). */
        msg = malloc(len + 1);
        if (!msg) {
                notice("Out of memory in chapms_handle_failure");
                return;
        }
        BCOPY(inp, msg, len);
        msg[len] = 0;
        p = msg;

        /*
         * Deal with MS-CHAP formatted failure messages; just print the
         * M=<message> part (if any).  For MS-CHAP we're not really supposed
         * to use M=<message>, but it shouldn't hurt.  See
         * chapms[2]_verify_response.
         */
        if (!strncmp(p, "E=", 2))
                err = strtol(p, NULL, 10); /* Remember the error code. */
        else
                goto print_msg; /* Message is badly formatted. */

        if (len && ((p = strstr(p, " M=")) != NULL)) {
                /* M=<message> field found. */
                p += 3;
        } else {
                /* No M=<message>; use the error code. */
                switch (err) {
                case MS_CHAP_ERROR_RESTRICTED_LOGON_HOURS:
                        p = "E=646 Restricted logon hours";
                        break;

                case MS_CHAP_ERROR_ACCT_DISABLED:
                        p = "E=647 Account disabled";
                        break;

                case MS_CHAP_ERROR_PASSWD_EXPIRED:
                        p = "E=648 Password expired";
                        break;

                case MS_CHAP_ERROR_NO_DIALIN_PERMISSION:
                        p = "E=649 No dialin permission";
                        break;

                case MS_CHAP_ERROR_AUTHENTICATION_FAILURE:
                        p = "E=691 Authentication failure";
                        break;

                case MS_CHAP_ERROR_CHANGING_PASSWORD:
                        /* Should never see this, we don't support Change Password. */
                        p = "E=709 Error changing password";
                        break;

                default:
                        free(msg);
                        error("Unknown MS-CHAP authentication failure: %.*v",
                              len, inp);
                        return;
                }
        }
print_msg:
        if (p != NULL)
                error("MS-CHAP authentication failed: %v", p);
        free(msg);
}

static void
ChallengeResponse(u_char *challenge,
                  u_char PasswordHash[MD4_SIGNATURE_SIZE],
                  u_char response[24])
{
    u_char    ZPasswordHash[21];

    BZERO(ZPasswordHash, sizeof(ZPasswordHash));
    BCOPY(PasswordHash, ZPasswordHash, MD4_SIGNATURE_SIZE);

#if 0
    dbglog("ChallengeResponse - ZPasswordHash %.*B",
           sizeof(ZPasswordHash), ZPasswordHash);
#endif

    (void) DesSetkey(ZPasswordHash + 0);
    DesEncrypt(challenge, response + 0);
    (void) DesSetkey(ZPasswordHash + 7);
    DesEncrypt(challenge, response + 8);
    (void) DesSetkey(ZPasswordHash + 14);
    DesEncrypt(challenge, response + 16);

#if 0
    dbglog("ChallengeResponse - response %.24B", response);
#endif
}

void
ChallengeHash(u_char PeerChallenge[16], u_char *rchallenge,
              char *username, u_char Challenge[8])
    
{
    SHA1_CTX    sha1Context;
    u_char      sha1Hash[SHA1_SIGNATURE_SIZE];
    char        *user;

    /* remove domain from "domain\username" */
    if ((user = strrchr(username, '\\')) != NULL)
        ++user;
    else
        user = username;

    SHA1_Init(&sha1Context);
    SHA1_Update(&sha1Context, PeerChallenge, 16);
    SHA1_Update(&sha1Context, rchallenge, 16);
    SHA1_Update(&sha1Context, (unsigned char *)user, strlen(user));
    SHA1_Final(sha1Hash, &sha1Context);

    BCOPY(sha1Hash, Challenge, 8);
}

/*
 * Convert the ASCII version of the password to Unicode.
 * This implicitly supports 8-bit ISO8859/1 characters.
 * This gives us the little-endian representation, which
 * is assumed by all M$ CHAP RFCs.  (Unicode byte ordering
 * is machine-dependent.)
 */
static void
ascii2unicode(char ascii[], int ascii_len, u_char unicode[])
{
    int i;

    BZERO(unicode, ascii_len * 2);
    for (i = 0; i < ascii_len; i++)
        unicode[i * 2] = (u_char) ascii[i];
}

static void
NTPasswordHash(char *secret, int secret_len, u_char hash[MD4_SIGNATURE_SIZE])
{
#ifdef __NetBSD__
    /* NetBSD uses the libc md4 routines which take bytes instead of bits */
    int                 mdlen = secret_len;
#else
    int                 mdlen = secret_len * 8;
#endif
    MD4_CTX             md4Context;

    MD4Init(&md4Context);
    MD4Update(&md4Context, (unsigned char *)secret, mdlen);
    MD4Final(hash, &md4Context);

}

static void
ChapMS_NT(u_char *rchallenge, char *secret, int secret_len,
          u_char NTResponse[24])
{
    u_char      unicodePassword[MAX_NT_PASSWORD * 2];
    u_char      PasswordHash[MD4_SIGNATURE_SIZE];

    /* Hash the Unicode version of the secret (== password). */
    ascii2unicode(secret, secret_len, unicodePassword);
    NTPasswordHash((char *)unicodePassword, secret_len * 2, PasswordHash);

    ChallengeResponse(rchallenge, PasswordHash, NTResponse);
}

static void
ChapMS2_NT(u_char *rchallenge, u_char PeerChallenge[16], char *username,
           char *secret, int secret_len, u_char NTResponse[24])
{
    u_char      unicodePassword[MAX_NT_PASSWORD * 2];
    u_char      PasswordHash[MD4_SIGNATURE_SIZE];
    u_char      Challenge[8];

    ChallengeHash(PeerChallenge, rchallenge, username, Challenge);

    /* Hash the Unicode version of the secret (== password). */
    ascii2unicode(secret, secret_len, unicodePassword);
    NTPasswordHash((char *)unicodePassword, secret_len * 2, PasswordHash);

    ChallengeResponse(Challenge, PasswordHash, NTResponse);
}

#ifdef MSLANMAN
static u_char *StdText = (u_char *)"KGS!@#$%"; /* key from rasapi32.dll */

static void
ChapMS_LANMan(u_char *rchallenge, char *secret, int secret_len,
              unsigned char *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]);
    (void) DesSetkey(UcasePassword + 0);
    DesEncrypt( StdText, PasswordHash + 0 );
    (void) DesSetkey(UcasePassword + 7);
    DesEncrypt( StdText, PasswordHash + 8 );
    ChallengeResponse(rchallenge, PasswordHash, &response[MS_CHAP_LANMANRESP]);
}
#endif


void
GenerateAuthenticatorResponse(u_char PasswordHashHash[MD4_SIGNATURE_SIZE],
                              u_char NTResponse[24], u_char PeerChallenge[16],
                              u_char *rchallenge, char *username,
                              u_char authResponse[MS_AUTH_RESPONSE_LENGTH+1])
{
    /*
     * "Magic" constants used in response generation, from RFC 2759.
     */
    u_char Magic1[39] = /* "Magic server to client signing constant" */
        { 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 };
    u_char Magic2[41] = /* "Pad to make it do more than one iteration" */
        { 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 };

    int         i;
    SHA1_CTX    sha1Context;
    u_char      Digest[SHA1_SIGNATURE_SIZE];
    u_char      Challenge[8];

    SHA1_Init(&sha1Context);
    SHA1_Update(&sha1Context, PasswordHashHash, MD4_SIGNATURE_SIZE);
    SHA1_Update(&sha1Context, NTResponse, 24);
    SHA1_Update(&sha1Context, Magic1, sizeof(Magic1));
    SHA1_Final(Digest, &sha1Context);

    ChallengeHash(PeerChallenge, rchallenge, username, Challenge);

    SHA1_Init(&sha1Context);
    SHA1_Update(&sha1Context, Digest, sizeof(Digest));
    SHA1_Update(&sha1Context, Challenge, sizeof(Challenge));
    SHA1_Update(&sha1Context, Magic2, sizeof(Magic2));
    SHA1_Final(Digest, &sha1Context);

    /* Convert to ASCII hex string. */
    for (i = 0; i < MAX((MS_AUTH_RESPONSE_LENGTH / 2), sizeof(Digest)); i++)
        sprintf((char *)&authResponse[i * 2], "%02X", Digest[i]);
}


static void
GenerateAuthenticatorResponsePlain
                (char *secret, int secret_len,
                 u_char NTResponse[24], u_char PeerChallenge[16],
                 u_char *rchallenge, char *username,
                 u_char authResponse[MS_AUTH_RESPONSE_LENGTH+1])
{
    u_char      unicodePassword[MAX_NT_PASSWORD * 2];
    u_char      PasswordHash[MD4_SIGNATURE_SIZE];
    u_char      PasswordHashHash[MD4_SIGNATURE_SIZE];

    /* Hash (x2) the Unicode version of the secret (== password). */
    ascii2unicode(secret, secret_len, unicodePassword);
    NTPasswordHash((char *)unicodePassword, secret_len * 2, PasswordHash);
    NTPasswordHash((char *)PasswordHash, sizeof(PasswordHash),
                   PasswordHashHash);

    GenerateAuthenticatorResponse(PasswordHashHash, NTResponse, PeerChallenge,
                                  rchallenge, username, authResponse);
}


#ifdef MPPE
/*
 * Set mppe_xxxx_key from the NTPasswordHashHash.
 * RFC 2548 (RADIUS support) requires us to export this function (ugh).
 */
void
mppe_set_keys(u_char *rchallenge, u_char PasswordHashHash[MD4_SIGNATURE_SIZE])
{
    SHA1_CTX    sha1Context;
    u_char      Digest[SHA1_SIGNATURE_SIZE];    /* >= MPPE_MAX_KEY_LEN */

    SHA1_Init(&sha1Context);
    SHA1_Update(&sha1Context, PasswordHashHash, MD4_SIGNATURE_SIZE);
    SHA1_Update(&sha1Context, PasswordHashHash, MD4_SIGNATURE_SIZE);
    SHA1_Update(&sha1Context, rchallenge, 8);
    SHA1_Final(Digest, &sha1Context);

    /* Same key in both directions. */
    BCOPY(Digest, mppe_send_key, sizeof(mppe_send_key));
    BCOPY(Digest, mppe_recv_key, sizeof(mppe_recv_key));

    mppe_keys_set = 1;
}

/*
 * Set mppe_xxxx_key from MS-CHAP credentials. (see RFC 3079)
 */
static void
Set_Start_Key(u_char *rchallenge, char *secret, int secret_len)
{
    u_char      unicodePassword[MAX_NT_PASSWORD * 2];
    u_char      PasswordHash[MD4_SIGNATURE_SIZE];
    u_char      PasswordHashHash[MD4_SIGNATURE_SIZE];

    /* Hash (x2) the Unicode version of the secret (== password). */
    ascii2unicode(secret, secret_len, unicodePassword);
    NTPasswordHash(unicodePassword, secret_len * 2, PasswordHash);
    NTPasswordHash(PasswordHash, sizeof(PasswordHash), PasswordHashHash);

    mppe_set_keys(rchallenge, PasswordHashHash);
}

/*
 * Set mppe_xxxx_key from MS-CHAPv2 credentials. (see RFC 3079)
 *
 * This helper function used in the Winbind module, which gets the
 * NTHashHash from the server.
 */
void
mppe_set_keys2(u_char PasswordHashHash[MD4_SIGNATURE_SIZE],
               u_char NTResponse[24], int IsServer)
{
    SHA1_CTX    sha1Context;
    u_char      MasterKey[SHA1_SIGNATURE_SIZE]; /* >= MPPE_MAX_KEY_LEN */
    u_char      Digest[SHA1_SIGNATURE_SIZE];    /* >= MPPE_MAX_KEY_LEN */

    u_char SHApad1[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 };
    u_char SHApad2[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 };

    /* "This is the MPPE Master Key" */
    u_char 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 };
    /* "On the client side, this is the send key; "
       "on the server side, it is the receive key." */
    u_char 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 };
    /* "On the client side, this is the receive key; "
       "on the server side, it is the send key." */
    u_char 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 };
    u_char *s;

    SHA1_Init(&sha1Context);
    SHA1_Update(&sha1Context, PasswordHashHash, MD4_SIGNATURE_SIZE);
    SHA1_Update(&sha1Context, NTResponse, 24);
    SHA1_Update(&sha1Context, Magic1, sizeof(Magic1));
    SHA1_Final(MasterKey, &sha1Context);

    /*
     * generate send key
     */
    if (IsServer)
        s = Magic3;
    else
        s = Magic2;
    SHA1_Init(&sha1Context);
    SHA1_Update(&sha1Context, MasterKey, 16);
    SHA1_Update(&sha1Context, SHApad1, sizeof(SHApad1));
    SHA1_Update(&sha1Context, s, 84);
    SHA1_Update(&sha1Context, SHApad2, sizeof(SHApad2));
    SHA1_Final(Digest, &sha1Context);

    BCOPY(Digest, mppe_send_key, sizeof(mppe_send_key));

    /*
     * generate recv key
     */
    if (IsServer)
        s = Magic2;
    else
        s = Magic3;
    SHA1_Init(&sha1Context);
    SHA1_Update(&sha1Context, MasterKey, 16);
    SHA1_Update(&sha1Context, SHApad1, sizeof(SHApad1));
    SHA1_Update(&sha1Context, s, 84);
    SHA1_Update(&sha1Context, SHApad2, sizeof(SHApad2));
    SHA1_Final(Digest, &sha1Context);

    BCOPY(Digest, mppe_recv_key, sizeof(mppe_recv_key));

    mppe_keys_set = 1;
}

/*
 * Set mppe_xxxx_key from MS-CHAPv2 credentials. (see RFC 3079)
 */
static void
SetMasterKeys(char *secret, int secret_len, u_char NTResponse[24], int IsServer)
{
    u_char      unicodePassword[MAX_NT_PASSWORD * 2];
    u_char      PasswordHash[MD4_SIGNATURE_SIZE];
    u_char      PasswordHashHash[MD4_SIGNATURE_SIZE];
    /* Hash (x2) the Unicode version of the secret (== password). */
    ascii2unicode(secret, secret_len, unicodePassword);
    NTPasswordHash(unicodePassword, secret_len * 2, PasswordHash);
    NTPasswordHash(PasswordHash, sizeof(PasswordHash), PasswordHashHash);
    mppe_set_keys2(PasswordHashHash, NTResponse, IsServer);
}

#endif /* MPPE */


void
ChapMS(u_char *rchallenge, char *secret, int secret_len,
       unsigned char *response)
{
    BZERO(response, MS_CHAP_RESPONSE_LEN);

    ChapMS_NT(rchallenge, secret, secret_len, &response[MS_CHAP_NTRESP]);

#ifdef MSLANMAN
    ChapMS_LANMan(rchallenge, secret, secret_len, &response);

    /* preferred method is set by option  */
    response[MS_CHAP_USENT] = !ms_lanman;
#else
    response[MS_CHAP_USENT] = 1;
#endif

#ifdef MPPE
    Set_Start_Key(rchallenge, secret, secret_len);
#endif
}


/*
 * If PeerChallenge is NULL, one is generated and the PeerChallenge
 * field of response is filled in.  Call this way when generating a response.
 * If PeerChallenge is supplied, it is copied into the PeerChallenge field.
 * Call this way when verifying a response (or debugging).
 * Do not call with PeerChallenge = response.
 *
 * The PeerChallenge field of response is then used for calculation of the
 * Authenticator Response.
 */
void
ChapMS2(u_char *rchallenge, u_char *PeerChallenge,
        char *user, char *secret, int secret_len, unsigned char *response,
        u_char authResponse[], int authenticator)
{
    /* ARGSUSED */
    u_char *p = &response[MS_CHAP2_PEER_CHALLENGE];
    int i;

    BZERO(response, sizeof(*response));

    /* Generate the Peer-Challenge if requested, or copy it if supplied. */
    if (!PeerChallenge)
        for (i = 0; i < MS_CHAP2_PEER_CHAL_LEN; i++)
            *p++ = (u_char) (drand48() * 0xff);
    else
        BCOPY(PeerChallenge, &response[MS_CHAP2_PEER_CHALLENGE],
              MS_CHAP2_PEER_CHAL_LEN);

    /* Generate the NT-Response */
    ChapMS2_NT(rchallenge, &response[MS_CHAP2_PEER_CHALLENGE], user,
               secret, secret_len, &response[MS_CHAP2_NTRESP]);

    /* Generate the Authenticator Response. */
    GenerateAuthenticatorResponsePlain(secret, secret_len,
                                       &response[MS_CHAP2_NTRESP],
                                       &response[MS_CHAP2_PEER_CHALLENGE],
                                       rchallenge, user, authResponse);

#ifdef MPPE
    SetMasterKeys(secret, secret_len,
                  &response[MS_CHAP2_NTRESP], authenticator);
#endif
}

#ifdef MPPE
/*
 * Set MPPE options from plugins.
 */
void
set_mppe_enc_types(int policy, int types)
{
    /* Early exit for unknown policies. */
    if (policy != MPPE_ENC_POL_ENC_ALLOWED ||
        policy != MPPE_ENC_POL_ENC_REQUIRED)
        return;

    /* Don't modify MPPE if it's optional and wasn't already configured. */
    if (policy == MPPE_ENC_POL_ENC_ALLOWED && !ccp_wantoptions[0].mppe)
        return;

    /*
     * Disable undesirable encryption types.  Note that we don't ENABLE
     * any encryption types, to avoid overriding manual configuration.
     */
    switch(types) {
        case MPPE_ENC_TYPES_RC4_40:
            ccp_wantoptions[0].mppe &= ~MPPE_OPT_128;   /* disable 128-bit */
            break;
        case MPPE_ENC_TYPES_RC4_128:
            ccp_wantoptions[0].mppe &= ~MPPE_OPT_40;    /* disable 40-bit */
            break;
        default:
            break;
    }
}
#endif /* MPPE */

static struct chap_digest_type chapms_digest = {
        CHAP_MICROSOFT,         /* code */
        chapms_generate_challenge,
        chapms_verify_response,
        chapms_make_response,
        NULL,                   /* check_success */
        chapms_handle_failure,
};

static struct chap_digest_type chapms2_digest = {
        CHAP_MICROSOFT_V2,      /* code */
        chapms2_generate_challenge,
        chapms2_verify_response,
        chapms2_make_response,
        chapms2_check_success,
        chapms_handle_failure,
};

void
chapms_init(void)
{
        chap_register_digest(&chapms_digest);
        chap_register_digest(&chapms2_digest);
        add_options(chapms_option_list);
}

#endif /* CHAPMS */