cd9b5a8761
Implemented encryption layer and some basic licensing negotiation. Reorganised code somewhat. While this is not quite as clean, it is a lot faster - our parser speed was becoming a bottle-neck. git-svn-id: svn://svn.code.sf.net/p/rdesktop/code/trunk/rdesktop@9 423420c4-83ab-492f-b58f-81f9feb106b5
241 lines
6.3 KiB
C
241 lines
6.3 KiB
C
/*
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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 1999-2000
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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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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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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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#include "rdesktop.h"
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#include "crypto/rc4.h"
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extern char username[16];
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extern char hostname[16];
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extern BOOL licence;
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static uint8 licence_key[16];
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static uint8 licence_sign_key[16];
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/* Generate a session key and RC4 keys, given client and server randoms */
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void licence_generate_keys(uint8 *client_key, uint8 *server_key,
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uint8 *client_rsa)
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{
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uint8 session_key[48];
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uint8 temp_hash[48];
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/* Generate session key - two rounds of sec_hash_48 */
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sec_hash_48(temp_hash, client_rsa, client_key, server_key, 65);
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sec_hash_48(session_key, temp_hash, server_key, client_key, 65);
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/* Store first 16 bytes of session key, for generating signatures */
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memcpy(licence_sign_key, session_key, 16);
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/* Generate RC4 key */
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sec_hash_16(licence_key, &session_key[16], client_key, server_key);
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}
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/* Send a licence request packet */
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static void licence_send_request(uint8 *client_random, uint8 *rsa_data,
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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 = 120 + userlen + hostlen;
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STREAM s;
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s = sec_init(sec_flags, length + 2);
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out_uint16_le(s, LICENCE_TAG_REQUEST);
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out_uint16_le(s, length);
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out_uint32_le(s, 1);
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out_uint32_le(s, 0xff010000);
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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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out_uint16(s, LICENCE_TAG_USER);
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out_uint16(s, userlen);
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out_uint8p(s, user, userlen);
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out_uint16(s, LICENCE_TAG_HOST);
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out_uint16(s, hostlen);
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out_uint8p(s, host, hostlen);
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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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/* Process a licence demand packet */
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static void 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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/* Retrieve the server random from the incoming packet */
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in_uint8p(s, server_random, SEC_RANDOM_SIZE);
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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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/* Send a certificate request back to the server */
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licence_send_request(null_data, null_data, username, hostname);
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}
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/* Send an authentication response packet */
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static void licence_send_authresp(uint8 *token, uint8 *crypt_hwid,
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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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s = sec_init(sec_flags, length + 2);
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out_uint16_le(s, LICENCE_TAG_AUTHRESP);
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out_uint16_le(s, length);
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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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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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out_uint8p(s, signature, LICENCE_SIGNATURE_SIZE);
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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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/* Parse an authentication request packet */
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static BOOL licence_parse_authreq(STREAM s, uint8 **token, uint8 **signature)
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{
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uint16 tokenlen;
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in_uint8s(s, 6); /* unknown: f8 3d 15 00 04 f6 */
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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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in_uint8p(s, *token, tokenlen);
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in_uint8p(s, *signature, LICENCE_SIGNATURE_SIZE);
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return s_check_end(s);
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}
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/* Process an authentication request packet */
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static void 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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/* 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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/* Decrypt the token. It should read TEST in Unicode. */
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RC4_set_key(&crypt_key, 16, licence_key);
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RC4(&crypt_key, LICENCE_TOKEN_SIZE, in_token, decrypt_token);
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/* Construct HWID */
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buf_out_uint32(hwid, 2);
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strncpy(hwid + 4, hostname, LICENCE_HWID_SIZE - 4);
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/* Generate a signature for a buffer of token and 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, licence_sign_key, 16,
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sealed_buffer, sizeof(sealed_buffer));
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/* Deliberately break signature if licencing disabled */
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if (!licence)
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memset(out_sig, 0, sizeof(out_sig));
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/* Now encrypt the HWID */
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RC4_set_key(&crypt_key, 16, licence_key);
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RC4(&crypt_key, LICENCE_HWID_SIZE, hwid, crypt_hwid);
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licence_send_authresp(out_token, crypt_hwid, out_sig);
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}
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/* Process an licence issue packet */
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static void 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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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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RC4_set_key(&crypt_key, 16, licence_key);
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RC4(&crypt_key, length, s->p, s->p);
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in_uint16(s, check);
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if (check != 0)
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return;
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/* We should save the licence here */
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STATUS("Server issued licence.\n");
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}
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/* Process a licence packet */
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void licence_process(STREAM s)
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{
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uint16 tag;
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in_uint16_le(s, tag);
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in_uint8s(s, 2); /* length */
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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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case LICENCE_TAG_AUTHREQ:
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licence_process_authreq(s);
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break;
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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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case LICENCE_TAG_RESULT:
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break;
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default:
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NOTIMP("licence tag 0x%x\n", tag);
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}
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}
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