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/* |
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rdesktop: A Remote Desktop Protocol client. |
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RDP licensing negotiation |
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Copyright (C) Matthew Chapman 1999-2005 |
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|
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This program is free software; you can redistribute it and/or modify |
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it under the terms of the GNU General Public License as published by |
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the Free Software Foundation; either version 2 of the License, or |
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(at your option) any later version. |
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|
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This program is distributed in the hope that it will be useful, |
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but WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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GNU General Public License for more details. |
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|
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You should have received a copy of the GNU General Public License |
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along with this program; if not, write to the Free Software |
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
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*/ |
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|
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#include "rdesktop.h" |
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#include <openssl/rc4.h> |
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|
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extern char g_username[16]; |
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extern char g_hostname[16]; |
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|
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static uint8 g_licence_key[16]; |
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static uint8 g_licence_sign_key[16]; |
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|
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BOOL g_licence_issued = False; |
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|
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/* Generate a session key and RC4 keys, given client and server randoms */ |
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static void |
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licence_generate_keys(uint8 * client_random, uint8 * server_random, uint8 * pre_master_secret) |
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{ |
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uint8 master_secret[48]; |
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uint8 key_block[48]; |
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|
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/* Generate master secret and then key material */ |
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sec_hash_48(master_secret, pre_master_secret, client_random, server_random, 'A'); |
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sec_hash_48(key_block, master_secret, server_random, client_random, 'A'); |
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|
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/* Store first 16 bytes of session key as MAC secret */ |
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memcpy(g_licence_sign_key, key_block, 16); |
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|
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/* Generate RC4 key from next 16 bytes */ |
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sec_hash_16(g_licence_key, &key_block[16], client_random, server_random); |
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} |
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|
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static void |
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licence_generate_hwid(uint8 * hwid) |
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{ |
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buf_out_uint32(hwid, 2); |
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strncpy((char *) (hwid + 4), g_hostname, LICENCE_HWID_SIZE - 4); |
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} |
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|
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/* Present an existing licence to the server */ |
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static void |
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licence_present(uint8 * client_random, uint8 * rsa_data, |
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uint8 * licence_data, int licence_size, uint8 * hwid, uint8 * signature) |
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{ |
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uint32 sec_flags = SEC_LICENCE_NEG; |
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uint16 length = |
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16 + SEC_RANDOM_SIZE + SEC_MODULUS_SIZE + SEC_PADDING_SIZE + |
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licence_size + LICENCE_HWID_SIZE + LICENCE_SIGNATURE_SIZE; |
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STREAM s; |
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|
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s = sec_init(sec_flags, length + 4); |
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|
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out_uint8(s, LICENCE_TAG_PRESENT); |
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out_uint8(s, 2); /* version */ |
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out_uint16_le(s, length); |
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|
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out_uint32_le(s, 1); |
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out_uint16(s, 0); |
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out_uint16_le(s, 0x0201); |
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|
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out_uint8p(s, client_random, SEC_RANDOM_SIZE); |
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out_uint16(s, 0); |
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out_uint16_le(s, (SEC_MODULUS_SIZE + SEC_PADDING_SIZE)); |
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out_uint8p(s, rsa_data, SEC_MODULUS_SIZE); |
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out_uint8s(s, SEC_PADDING_SIZE); |
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|
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out_uint16_le(s, 1); |
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out_uint16_le(s, licence_size); |
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out_uint8p(s, licence_data, licence_size); |
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|
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out_uint16_le(s, 1); |
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out_uint16_le(s, LICENCE_HWID_SIZE); |
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out_uint8p(s, hwid, LICENCE_HWID_SIZE); |
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|
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out_uint8p(s, signature, LICENCE_SIGNATURE_SIZE); |
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|
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s_mark_end(s); |
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sec_send(s, sec_flags); |
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} |
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|
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/* Send a licence request packet */ |
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static void |
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licence_send_request(uint8 * client_random, uint8 * rsa_data, char *user, char *host) |
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{ |
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uint32 sec_flags = SEC_LICENCE_NEG; |
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uint16 userlen = strlen(user) + 1; |
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uint16 hostlen = strlen(host) + 1; |
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uint16 length = 128 + userlen + hostlen; |
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STREAM s; |
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|
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s = sec_init(sec_flags, length + 2); |
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|
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out_uint8(s, LICENCE_TAG_REQUEST); |
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out_uint8(s, 2); /* version */ |
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out_uint16_le(s, length); |
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|
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out_uint32_le(s, 1); |
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out_uint16(s, 0); |
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out_uint16_le(s, 0xff01); |
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|
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out_uint8p(s, client_random, SEC_RANDOM_SIZE); |
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out_uint16(s, 0); |
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out_uint16_le(s, (SEC_MODULUS_SIZE + SEC_PADDING_SIZE)); |
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out_uint8p(s, rsa_data, SEC_MODULUS_SIZE); |
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out_uint8s(s, SEC_PADDING_SIZE); |
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|
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out_uint16_le(s, LICENCE_TAG_USER); |
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out_uint16_le(s, userlen); |
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out_uint8p(s, user, userlen); |
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|
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out_uint16_le(s, LICENCE_TAG_HOST); |
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out_uint16_le(s, hostlen); |
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out_uint8p(s, host, hostlen); |
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|
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s_mark_end(s); |
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sec_send(s, sec_flags); |
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} |
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|
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/* Process a licence demand packet */ |
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static void |
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licence_process_demand(STREAM s) |
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{ |
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uint8 null_data[SEC_MODULUS_SIZE]; |
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uint8 *server_random; |
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uint8 signature[LICENCE_SIGNATURE_SIZE]; |
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uint8 hwid[LICENCE_HWID_SIZE]; |
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uint8 *licence_data; |
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int licence_size; |
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RC4_KEY crypt_key; |
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|
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/* Retrieve the server random from the incoming packet */ |
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in_uint8p(s, server_random, SEC_RANDOM_SIZE); |
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|
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/* We currently use null client keys. This is a bit naughty but, hey, |
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the security of licence negotiation isn't exactly paramount. */ |
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memset(null_data, 0, sizeof(null_data)); |
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licence_generate_keys(null_data, server_random, null_data); |
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|
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licence_size = load_licence(&licence_data); |
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if (licence_size > 0) |
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{ |
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/* Generate a signature for the HWID buffer */ |
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licence_generate_hwid(hwid); |
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sec_sign(signature, 16, g_licence_sign_key, 16, hwid, sizeof(hwid)); |
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|
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/* Now encrypt the HWID */ |
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RC4_set_key(&crypt_key, 16, g_licence_key); |
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RC4(&crypt_key, sizeof(hwid), hwid, hwid); |
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|
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licence_present(null_data, null_data, licence_data, licence_size, hwid, signature); |
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xfree(licence_data); |
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return; |
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} |
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|
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licence_send_request(null_data, null_data, g_username, g_hostname); |
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} |
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|
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/* Send an authentication response packet */ |
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static void |
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licence_send_authresp(uint8 * token, uint8 * crypt_hwid, uint8 * signature) |
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{ |
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uint32 sec_flags = SEC_LICENCE_NEG; |
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uint16 length = 58; |
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STREAM s; |
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|
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s = sec_init(sec_flags, length + 2); |
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|
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out_uint8(s, LICENCE_TAG_AUTHRESP); |
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out_uint8(s, 2); /* version */ |
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out_uint16_le(s, length); |
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|
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out_uint16_le(s, 1); |
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out_uint16_le(s, LICENCE_TOKEN_SIZE); |
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out_uint8p(s, token, LICENCE_TOKEN_SIZE); |
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|
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out_uint16_le(s, 1); |
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out_uint16_le(s, LICENCE_HWID_SIZE); |
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out_uint8p(s, crypt_hwid, LICENCE_HWID_SIZE); |
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|
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out_uint8p(s, signature, LICENCE_SIGNATURE_SIZE); |
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|
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s_mark_end(s); |
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sec_send(s, sec_flags); |
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} |
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|
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/* Parse an authentication request packet */ |
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static BOOL |
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licence_parse_authreq(STREAM s, uint8 ** token, uint8 ** signature) |
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{ |
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uint16 tokenlen; |
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|
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in_uint8s(s, 6); /* unknown: f8 3d 15 00 04 f6 */ |
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|
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in_uint16_le(s, tokenlen); |
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if (tokenlen != LICENCE_TOKEN_SIZE) |
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{ |
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error("token len %d\n", tokenlen); |
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return False; |
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} |
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|
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in_uint8p(s, *token, tokenlen); |
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in_uint8p(s, *signature, LICENCE_SIGNATURE_SIZE); |
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|
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return s_check_end(s); |
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} |
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|
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/* Process an authentication request packet */ |
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static void |
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licence_process_authreq(STREAM s) |
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{ |
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uint8 *in_token, *in_sig; |
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uint8 out_token[LICENCE_TOKEN_SIZE], decrypt_token[LICENCE_TOKEN_SIZE]; |
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uint8 hwid[LICENCE_HWID_SIZE], crypt_hwid[LICENCE_HWID_SIZE]; |
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uint8 sealed_buffer[LICENCE_TOKEN_SIZE + LICENCE_HWID_SIZE]; |
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uint8 out_sig[LICENCE_SIGNATURE_SIZE]; |
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RC4_KEY crypt_key; |
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|
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/* Parse incoming packet and save the encrypted token */ |
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licence_parse_authreq(s, &in_token, &in_sig); |
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memcpy(out_token, in_token, LICENCE_TOKEN_SIZE); |
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|
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/* Decrypt the token. It should read TEST in Unicode. */ |
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RC4_set_key(&crypt_key, 16, g_licence_key); |
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RC4(&crypt_key, LICENCE_TOKEN_SIZE, in_token, decrypt_token); |
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|
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/* Generate a signature for a buffer of token and HWID */ |
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licence_generate_hwid(hwid); |
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memcpy(sealed_buffer, decrypt_token, LICENCE_TOKEN_SIZE); |
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memcpy(sealed_buffer + LICENCE_TOKEN_SIZE, hwid, LICENCE_HWID_SIZE); |
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sec_sign(out_sig, 16, g_licence_sign_key, 16, sealed_buffer, sizeof(sealed_buffer)); |
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|
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/* Now encrypt the HWID */ |
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RC4_set_key(&crypt_key, 16, g_licence_key); |
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RC4(&crypt_key, LICENCE_HWID_SIZE, hwid, crypt_hwid); |
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|
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licence_send_authresp(out_token, crypt_hwid, out_sig); |
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} |
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|
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/* Process an licence issue packet */ |
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static void |
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licence_process_issue(STREAM s) |
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{ |
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RC4_KEY crypt_key; |
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uint32 length; |
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uint16 check; |
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int i; |
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|
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in_uint8s(s, 2); /* 3d 45 - unknown */ |
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in_uint16_le(s, length); |
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if (!s_check_rem(s, length)) |
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return; |
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|
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RC4_set_key(&crypt_key, 16, g_licence_key); |
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RC4(&crypt_key, length, s->p, s->p); |
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|
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in_uint16(s, check); |
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if (check != 0) |
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return; |
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|
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g_licence_issued = True; |
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|
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in_uint8s(s, 2); /* pad */ |
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|
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/* advance to fourth string */ |
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length = 0; |
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for (i = 0; i < 4; i++) |
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{ |
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in_uint8s(s, length); |
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in_uint32_le(s, length); |
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if (!s_check_rem(s, length)) |
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return; |
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} |
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|
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g_licence_issued = True; |
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save_licence(s->p, length); |
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} |
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|
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/* Process a licence packet */ |
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void |
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licence_process(STREAM s) |
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{ |
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uint8 tag; |
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|
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in_uint8(s, tag); |
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in_uint8s(s, 3); /* version, length */ |
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|
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switch (tag) |
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{ |
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case LICENCE_TAG_DEMAND: |
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licence_process_demand(s); |
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break; |
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|
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case LICENCE_TAG_AUTHREQ: |
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licence_process_authreq(s); |
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break; |
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|
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case LICENCE_TAG_ISSUE: |
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licence_process_issue(s); |
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break; |
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|
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case LICENCE_TAG_REISSUE: |
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case LICENCE_TAG_RESULT: |
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break; |
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|
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default: |
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unimpl("licence tag 0x%x\n", tag); |
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} |
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} |