source: vbox/trunk/src/VBox/RDP/client-1.8.3/licence.c@ 61547

/* -*- c-basic-offset: 8 -*-
   rdesktop: A Remote Desktop Protocol client.
   RDP licensing negotiation
   Copyright (C) Matthew Chapman <matthewc.unsw.edu.au> 1999-2008
   Copyright (C) Thomas Uhle <[email protected]> 2011
   Copyright (C) Henrik Andersson <[email protected]> 2014


   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/>.
*/

/*
 * Oracle GPL Disclaimer: For the avoidance of doubt, except that if any license choice
 * other than GPL or LGPL is available it will apply instead, Oracle elects to use only
 * the General Public License version 2 (GPLv2) at this time for any software where
 * a choice of GPL license versions is made available with the language indicating
 * that GPLv2 or any later version may be used, or where a choice of which version
 * of the GPL is applied is otherwise unspecified.
 */

#include "rdesktop.h"
#include "ssl.h"

extern char *g_username;
extern char g_hostname[16];
extern RDP_VERSION g_rdp_version;

static uint8 g_licence_key[16];
static uint8 g_licence_sign_key[16];

RD_BOOL g_licence_issued = False;
RD_BOOL g_licence_error_result = False;

/* Generate a session key and RC4 keys, given client and server randoms */
static void
licence_generate_keys(uint8 * client_random, uint8 * server_random, uint8 * pre_master_secret)
{
        uint8 master_secret[48];
        uint8 key_block[48];

        /* Generate master secret and then key material */
        sec_hash_48(master_secret, pre_master_secret, client_random, server_random, 'A');
        sec_hash_48(key_block, master_secret, server_random, client_random, 'A');

        /* Store first 16 bytes of session key as MAC secret */
        memcpy(g_licence_sign_key, key_block, 16);

        /* Generate RC4 key from next 16 bytes */
        sec_hash_16(g_licence_key, &key_block[16], client_random, server_random);
}

static void
licence_generate_hwid(uint8 * hwid)
{
        buf_out_uint32(hwid, 2);
        strncpy((char *) (hwid + 4), g_hostname, LICENCE_HWID_SIZE - 4);
}

/* Send a lincece info packet to server */
static void
licence_info(uint8 * client_random, uint8 * rsa_data,
             uint8 * licence_data, int licence_size, uint8 * hwid, uint8 * signature)
{
        uint32 sec_flags = SEC_LICENCE_NEG;
        uint16 length =
                24 + SEC_RANDOM_SIZE + SEC_MODULUS_SIZE + SEC_PADDING_SIZE +
                licence_size + LICENCE_HWID_SIZE + LICENCE_SIGNATURE_SIZE;
        STREAM s;

        s = sec_init(sec_flags, length + 2);

        out_uint8(s, LICENCE_TAG_LICENCE_INFO);
        out_uint8(s, ((g_rdp_version >= RDP_V5) ? 3 : 2));      /* version */
        out_uint16_le(s, length);

        out_uint32_le(s, 1);
        out_uint16(s, 0);
        out_uint16_le(s, 0x0201);

        out_uint8p(s, client_random, SEC_RANDOM_SIZE);
        out_uint16_le(s, 2);
        out_uint16_le(s, (SEC_MODULUS_SIZE + SEC_PADDING_SIZE));
        out_uint8p(s, rsa_data, SEC_MODULUS_SIZE);
        out_uint8s(s, SEC_PADDING_SIZE);

        out_uint16_le(s, 1);
        out_uint16_le(s, licence_size);
        out_uint8p(s, licence_data, licence_size);

        out_uint16_le(s, 1);
        out_uint16_le(s, LICENCE_HWID_SIZE);
        out_uint8p(s, hwid, LICENCE_HWID_SIZE);

        out_uint8p(s, signature, LICENCE_SIGNATURE_SIZE);

        s_mark_end(s);
        sec_send(s, sec_flags);
}

/* Send a new licence request packet */
static void
licence_send_new_licence_request(uint8 * client_random, uint8 * rsa_data, char *user, char *host)
{
        uint32 sec_flags = SEC_LICENCE_NEG;
        uint16 userlen = strlen(user) + 1;
        uint16 hostlen = strlen(host) + 1;
        uint16 length =
                24 + SEC_RANDOM_SIZE + SEC_MODULUS_SIZE + SEC_PADDING_SIZE + userlen + hostlen;
        STREAM s;

        s = sec_init(sec_flags, length + 2);

        out_uint8(s, LICENCE_TAG_NEW_LICENCE_REQUEST);
        out_uint8(s, ((g_rdp_version >= RDP_V5) ? 3 : 2));      /* version */
        out_uint16_le(s, length);

        out_uint32_le(s, 1);    // KEY_EXCHANGE_ALG_RSA
        out_uint16(s, 0);
        out_uint16_le(s, 0xff01);

        out_uint8p(s, client_random, SEC_RANDOM_SIZE);
        out_uint16_le(s, 2);
        out_uint16_le(s, (SEC_MODULUS_SIZE + SEC_PADDING_SIZE));
        out_uint8p(s, rsa_data, SEC_MODULUS_SIZE);
        out_uint8s(s, SEC_PADDING_SIZE);

        /* Username LICENSE_BINARY_BLOB */
        out_uint16_le(s, BB_CLIENT_USER_NAME_BLOB);
        out_uint16_le(s, userlen);
        out_uint8p(s, user, userlen);

        /* Machinename LICENSE_BINARY_BLOB */
        out_uint16_le(s, BB_CLIENT_MACHINE_NAME_BLOB);
        out_uint16_le(s, hostlen);
        out_uint8p(s, host, hostlen);

        s_mark_end(s);
        sec_send(s, sec_flags);
}

/* Process a licence request packet */
static void
licence_process_request(STREAM s)
{
        uint8 null_data[SEC_MODULUS_SIZE];
        uint8 *server_random;
        uint8 signature[LICENCE_SIGNATURE_SIZE];
        uint8 hwid[LICENCE_HWID_SIZE];
        uint8 *licence_data;
        int licence_size;
        RDSSL_RC4 crypt_key;

        /* Retrieve the server random from the incoming packet */
        in_uint8p(s, server_random, SEC_RANDOM_SIZE);

        /* We currently use null client keys. This is a bit naughty but, hey,
           the security of licence negotiation isn't exactly paramount. */
        memset(null_data, 0, sizeof(null_data));
        licence_generate_keys(null_data, server_random, null_data);

        licence_size = load_licence(&licence_data);
        if (licence_size > 0)
        {
                /* Generate a signature for the HWID buffer */
                licence_generate_hwid(hwid);
                sec_sign(signature, 16, g_licence_sign_key, 16, hwid, sizeof(hwid));

                /* Now encrypt the HWID */
                rdssl_rc4_set_key(&crypt_key, g_licence_key, 16);
                rdssl_rc4_crypt(&crypt_key, hwid, hwid, sizeof(hwid));

#if WITH_DEBUG
                DEBUG(("Sending licensing PDU (message type 0x%02x)\n", LICENCE_TAG_LICENCE_INFO));
#endif
                licence_info(null_data, null_data, licence_data, licence_size, hwid, signature);

                xfree(licence_data);
                return;
        }

#if WITH_DEBUG
        DEBUG(("Sending licensing PDU (message type 0x%02x)\n", LICENCE_TAG_NEW_LICENCE_REQUEST));
#endif
        licence_send_new_licence_request(null_data, null_data, g_username, g_hostname);
}

/* Send a platform challange response packet */
static void
licence_send_platform_challange_response(uint8 * token, uint8 * crypt_hwid, uint8 * signature)
{
        uint32 sec_flags = SEC_LICENCE_NEG;
        uint16 length = 58;
        STREAM s;

        s = sec_init(sec_flags, length + 2);

        out_uint8(s, LICENCE_TAG_PLATFORM_CHALLANGE_RESPONSE);
        out_uint8(s, ((g_rdp_version >= RDP_V5) ? 3 : 2));      /* version */
        out_uint16_le(s, length);

        out_uint16_le(s, 1);
        out_uint16_le(s, LICENCE_TOKEN_SIZE);
        out_uint8p(s, token, LICENCE_TOKEN_SIZE);

        out_uint16_le(s, 1);
        out_uint16_le(s, LICENCE_HWID_SIZE);
        out_uint8p(s, crypt_hwid, LICENCE_HWID_SIZE);

        out_uint8p(s, signature, LICENCE_SIGNATURE_SIZE);

        s_mark_end(s);
        sec_send(s, sec_flags);
}

/* Parse an platform challange request packet */
static RD_BOOL
licence_parse_platform_challange(STREAM s, uint8 ** token, uint8 ** signature)
{
        uint16 tokenlen;

        in_uint8s(s, 6);        /* unknown: f8 3d 15 00 04 f6 */

        in_uint16_le(s, tokenlen);
        if (tokenlen != LICENCE_TOKEN_SIZE)
        {
                error("token len %d\n", tokenlen);
                return False;
        }

        in_uint8p(s, *token, tokenlen);
        in_uint8p(s, *signature, LICENCE_SIGNATURE_SIZE);

        return s_check_end(s);
}

/* Process a platform challange  packet */
static void
licence_process_platform_challange(STREAM s)
{
        uint8 *in_token = NULL, *in_sig;
        uint8 out_token[LICENCE_TOKEN_SIZE], decrypt_token[LICENCE_TOKEN_SIZE];
        uint8 hwid[LICENCE_HWID_SIZE], crypt_hwid[LICENCE_HWID_SIZE];
        uint8 sealed_buffer[LICENCE_TOKEN_SIZE + LICENCE_HWID_SIZE];
        uint8 out_sig[LICENCE_SIGNATURE_SIZE];
        RDSSL_RC4 crypt_key;

        /* Parse incoming packet and save the encrypted token */
        licence_parse_platform_challange(s, &in_token, &in_sig);
        memcpy(out_token, in_token, LICENCE_TOKEN_SIZE);

        /* Decrypt the token. It should read TEST in Unicode. */
        rdssl_rc4_set_key(&crypt_key, g_licence_key, 16);
        rdssl_rc4_crypt(&crypt_key, in_token, decrypt_token, LICENCE_TOKEN_SIZE);

        /* Generate a signature for a buffer of token and HWID */
        licence_generate_hwid(hwid);
        memcpy(sealed_buffer, decrypt_token, LICENCE_TOKEN_SIZE);
        memcpy(sealed_buffer + LICENCE_TOKEN_SIZE, hwid, LICENCE_HWID_SIZE);
        sec_sign(out_sig, 16, g_licence_sign_key, 16, sealed_buffer, sizeof(sealed_buffer));

        /* Now encrypt the HWID */
        rdssl_rc4_set_key(&crypt_key, g_licence_key, 16);
        rdssl_rc4_crypt(&crypt_key, hwid, crypt_hwid, LICENCE_HWID_SIZE);

        licence_send_platform_challange_response(out_token, crypt_hwid, out_sig);
}

/* Process a new licence packet */
static void
licence_process_new_license(STREAM s)
{
        RDSSL_RC4 crypt_key;
        uint32 length;
        int i;

        in_uint8s(s, 2);        // Skip license binary blob type
        in_uint16_le(s, length);
        if (!s_check_rem(s, length))
                return;

        rdssl_rc4_set_key(&crypt_key, g_licence_key, 16);
        rdssl_rc4_crypt(&crypt_key, s->p, s->p, length);

        /* Parse NEW_LICENSE_INFO block */
        in_uint8s(s, 4);        // skip dwVersion

        /* Skip strings, Scope, CompanyName and ProductId to get
           to the LicenseInfo which we store in license blob. */
        length = 0;
        for (i = 0; i < 4; i++)
        {
                in_uint8s(s, length);
                in_uint32_le(s, length);
                if (!s_check_rem(s, length))
                        return;
        }

        g_licence_issued = True;
        save_licence(s->p, length);
}

/* process a licence error alert packet */
void
licence_process_error_alert(STREAM s)
{
        uint32 error_code;
        uint32 state_transition;
        uint32 error_info;
        in_uint32(s, error_code);
        in_uint32(s, state_transition);
        in_uint32(s, error_info);

        /* There is a special case in the error alert handling, when licensing is all good
           and the server is not sending a license to client, a "Server License Error PDU -
           Valid Client" packet is sent which means, every thing is ok.

           Therefor we should flag that everything is ok with license here.
         */
        if (error_code == 0x07)
        {
                g_licence_issued = True;
                return;
        }

        /* handle error codes, for now, jsut report them */
        switch (error_code)
        {
                case 0x6:       // ERR_NO_LICENSE_SERVER
                        warning("License error alert from server: No license server\n");
                        break;

                case 0x8:       // ERR_INVALID_CLIENT
                        warning("License error alert from server: Invalid client\n");
                        break;

                case 0x4:       // ERR_INVALID_SCOPE
                case 0xb:       // ERR_INVALID_PRODUCTID
                case 0xc:       // ERR_INVALID_MESSAGE_LENGTH
                default:
                        warning("License error alert from server: code %u, state transition %u\n",
                                error_code, state_transition);
                        break;
        }

        g_licence_error_result = True;
}


/* Process a licence packet */
void
licence_process(STREAM s)
{
        uint8 tag;

        in_uint8(s, tag);
        in_uint8s(s, 3);        /* version, length */

#if WITH_DEBUG
        DEBUG(("Received licensing PDU (message type 0x%02x)\n", tag));
#endif

        switch (tag)
        {
                case LICENCE_TAG_REQUEST:
                        licence_process_request(s);
                        break;

                case LICENCE_TAG_PLATFORM_CHALLANGE:
                        licence_process_platform_challange(s);
                        break;

                case LICENCE_TAG_NEW_LICENCE:
                case LICENCE_TAG_UPGRADE_LICENCE:
                        /* we can handle new and upgrades of licences the same way. */
                        licence_process_new_license(s);
                        break;

                case LICENCE_TAG_ERROR_ALERT:
                        licence_process_error_alert(s);
                        break;

                default:
                        unimpl("licence tag 0x%02x\n", tag);
        }
}