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/* -*- 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 <thomas.uhle@mailbox.tu-dresden.de> 2011
Copyright (C) Henrik Andersson <henrik.andersson@cendio.com> 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/>.
*/
#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_uint8a(s, client_random, SEC_RANDOM_SIZE);
out_uint16_le(s, 2);
out_uint16_le(s, (SEC_MODULUS_SIZE + SEC_PADDING_SIZE));
out_uint8a(s, rsa_data, SEC_MODULUS_SIZE);
out_uint8s(s, SEC_PADDING_SIZE);
out_uint16_le(s, 1);
out_uint16_le(s, licence_size);
out_uint8a(s, licence_data, licence_size);
out_uint16_le(s, 1);
out_uint16_le(s, LICENCE_HWID_SIZE);
out_uint8a(s, hwid, LICENCE_HWID_SIZE);
out_uint8a(s, signature, LICENCE_SIGNATURE_SIZE);
s_mark_end(s);
sec_send(s, sec_flags);
s_free(s);
}
/* 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_uint8a(s, client_random, SEC_RANDOM_SIZE);
out_uint16_le(s, 2);
out_uint16_le(s, (SEC_MODULUS_SIZE + SEC_PADDING_SIZE));
out_uint8a(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_uint8a(s, user, userlen);
/* Machinename LICENSE_BINARY_BLOB */
out_uint16_le(s, BB_CLIENT_MACHINE_NAME_BLOB);
out_uint16_le(s, hostlen);
out_uint8a(s, host, hostlen);
s_mark_end(s);
sec_send(s, sec_flags);
s_free(s);
}
/* 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_uint8a(s, token, LICENCE_TOKEN_SIZE);
out_uint16_le(s, 1);
out_uint16_le(s, LICENCE_HWID_SIZE);
out_uint8a(s, crypt_hwid, LICENCE_HWID_SIZE);
out_uint8a(s, signature, LICENCE_SIGNATURE_SIZE);
s_mark_end(s);
sec_send(s, sec_flags);
s_free(s);
}
/* 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)
{
unsigned char *data;
size_t before;
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;
before = s_tell(s);
inout_uint8p(s, data, length);
rdssl_rc4_set_key(&crypt_key, g_licence_key, 16);
rdssl_rc4_crypt(&crypt_key, data, data, length);
s_seek(s, before);
/* 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;
in_uint8p(s, data, length);
save_licence(data, 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);
}
}
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