source: branches/samba-3.2.x/source/libsmb/credentials.c@ 612

/* 
   Unix SMB/CIFS implementation.
   code to manipulate domain credentials
   Copyright (C) Andrew Tridgell 1997-1998
   Largely rewritten by Jeremy Allison 2005.
   
   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 3 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, see <http://www.gnu.org/licenses/>.
*/

#include "includes.h"

/****************************************************************************
 Represent a credential as a string.
****************************************************************************/

char *credstr(const unsigned char *cred)
{
        char *result;
        result = talloc_asprintf(talloc_tos(),
                                 "%02X%02X%02X%02X%02X%02X%02X%02X",
                                 cred[0], cred[1], cred[2], cred[3],
                                 cred[4], cred[5], cred[6], cred[7]);
        SMB_ASSERT(result != NULL);
        return result;
}

/****************************************************************************
 Setup the session key and the client and server creds in dc.
 ADS-style 128 bit session keys.
 Used by both client and server creds setup.
****************************************************************************/

static void creds_init_128(struct dcinfo *dc,
                           const struct netr_Credential *clnt_chal_in,
                           const struct netr_Credential *srv_chal_in,
                           const unsigned char mach_pw[16])
{
        unsigned char zero[4], tmp[16];
        HMACMD5Context ctx;
        struct MD5Context md5;

        /* Just in case this isn't already there */
        memcpy(dc->mach_pw, mach_pw, 16);

        ZERO_STRUCT(dc->sess_key);

        memset(zero, 0, sizeof(zero));

        hmac_md5_init_rfc2104(mach_pw, 16, &ctx);
        MD5Init(&md5);
        MD5Update(&md5, zero, sizeof(zero));
        MD5Update(&md5, clnt_chal_in->data, 8);
        MD5Update(&md5, srv_chal_in->data, 8);
        MD5Final(tmp, &md5);
        hmac_md5_update(tmp, sizeof(tmp), &ctx);
        hmac_md5_final(dc->sess_key, &ctx);

        /* debug output */
        DEBUG(5,("creds_init_128\n"));
        DEBUG(5,("\tclnt_chal_in: %s\n", credstr(clnt_chal_in->data)));
        DEBUG(5,("\tsrv_chal_in : %s\n", credstr(srv_chal_in->data)));
        dump_data_pw("\tsession_key ", (const unsigned char *)dc->sess_key, 16);

        /* Generate the next client and server creds. */
        
        des_crypt112(dc->clnt_chal.data,                /* output */
                        clnt_chal_in->data,             /* input */
                        dc->sess_key,                   /* input */
                        1);

        des_crypt112(dc->srv_chal.data,                 /* output */
                        srv_chal_in->data,              /* input */
                        dc->sess_key,                   /* input */
                        1);

        /* Seed is the client chal. */
        memcpy(dc->seed_chal.data, dc->clnt_chal.data, 8);
}

/****************************************************************************
 Setup the session key and the client and server creds in dc.
 Used by both client and server creds setup.
****************************************************************************/

static void creds_init_64(struct dcinfo *dc,
                          const struct netr_Credential *clnt_chal_in,
                          const struct netr_Credential *srv_chal_in,
                          const unsigned char mach_pw[16])
{
        uint32 sum[2];
        unsigned char sum2[8];

        /* Just in case this isn't already there */
        if (dc->mach_pw != mach_pw) {
                memcpy(dc->mach_pw, mach_pw, 16);
        }

        sum[0] = IVAL(clnt_chal_in->data, 0) + IVAL(srv_chal_in->data, 0);
        sum[1] = IVAL(clnt_chal_in->data, 4) + IVAL(srv_chal_in->data, 4);

        SIVAL(sum2,0,sum[0]);
        SIVAL(sum2,4,sum[1]);

        ZERO_STRUCT(dc->sess_key);

        des_crypt128(dc->sess_key, sum2, dc->mach_pw);

        /* debug output */
        DEBUG(5,("creds_init_64\n"));
        DEBUG(5,("\tclnt_chal_in: %s\n", credstr(clnt_chal_in->data)));
        DEBUG(5,("\tsrv_chal_in : %s\n", credstr(srv_chal_in->data)));
        DEBUG(5,("\tclnt+srv : %s\n", credstr(sum2)));
        DEBUG(5,("\tsess_key_out : %s\n", credstr(dc->sess_key)));

        /* Generate the next client and server creds. */
        
        des_crypt112(dc->clnt_chal.data,                /* output */
                        clnt_chal_in->data,             /* input */
                        dc->sess_key,                   /* input */
                        1);

        des_crypt112(dc->srv_chal.data,                 /* output */
                        srv_chal_in->data,              /* input */
                        dc->sess_key,                   /* input */
                        1);

        /* Seed is the client chal. */
        memcpy(dc->seed_chal.data, dc->clnt_chal.data, 8);
}

/****************************************************************************
 Utility function to step credential chain one forward.
 Deliberately doesn't update the seed. See reseed comment below.
****************************************************************************/

static void creds_step(struct dcinfo *dc)
{
        DOM_CHAL time_chal;

        DEBUG(5,("\tsequence = 0x%x\n", (unsigned int)dc->sequence ));

        DEBUG(5,("\tseed:        %s\n", credstr(dc->seed_chal.data) ));

        SIVAL(time_chal.data, 0, IVAL(dc->seed_chal.data, 0) + dc->sequence);
        SIVAL(time_chal.data, 4, IVAL(dc->seed_chal.data, 4));
                                                                                                   
        DEBUG(5,("\tseed+seq   %s\n", credstr(time_chal.data) ));

        des_crypt112(dc->clnt_chal.data, time_chal.data, dc->sess_key, 1);

        DEBUG(5,("\tCLIENT      %s\n", credstr(dc->clnt_chal.data) ));

        SIVAL(time_chal.data, 0, IVAL(dc->seed_chal.data, 0) + dc->sequence + 1);
        SIVAL(time_chal.data, 4, IVAL(dc->seed_chal.data, 4));

        DEBUG(5,("\tseed+seq+1   %s\n", credstr(time_chal.data) ));

        des_crypt112(dc->srv_chal.data, time_chal.data, dc->sess_key, 1);

        DEBUG(5,("\tSERVER      %s\n", credstr(dc->srv_chal.data) ));
}

/****************************************************************************