├── inc
    ├── autoload.php
    └── class-checksum-verifier.php
├── checksum-verifier.php
├── README.md
└── LICENSE.txt


/inc/autoload.php:
--------------------------------------------------------------------------------
 1 | <?php
 2 | /**
 3 |  * Checksum-Verifier: Autoloader
 4 |  *
 5 |  * @package Checksum-Verifier
 6 |  * @since   0.0.1
 7 |  */
 8 | 
 9 | // Quit.
10 | defined( 'ABSPATH' ) || exit;
11 | 
12 | // Register autoload.
13 | spl_autoload_register( 'checksum_verifier_autoload' );
14 | 
15 | /**
16 |  * Perform autoload.
17 |  *
18 |  * @param string $class The classname.
19 |  */
20 | function checksum_verifier_autoload( $class ) {
21 | 	if ( in_array( $class, array( 'Checksum_Verifier' ), true ) ) {
22 | 		require_once sprintf(
23 | 			'%s%sclass-%s.php',
24 | 			dirname( __FILE__ ),
25 | 			DIRECTORY_SEPARATOR,
26 | 			strtolower( str_replace( '_', '-', $class ) )
27 | 		);
28 | 	}
29 | }
30 | 


--------------------------------------------------------------------------------
/checksum-verifier.php:
--------------------------------------------------------------------------------
  1 | <?php
  2 | /**
  3 |  * Checksum Verifier
  4 |  *
  5 |  * @package     ChecksumVerifier
  6 |  * @author      pluginkollektiv
  7 |  * @license     GPL-2.0+
  8 |  *
  9 |  * @wordpress-plugin
 10 |  * Plugin Name: Checksum Verifier
 11 |  * Plugin URI:  https://wordpress.org/plugins/checksum-verifier/
 12 |  * Description: Verifies MD5 checksums of WordPress core files, sends e-mail to the mail address of your admin user warning in case of threat. Just activate it and you are done.
 13 |  * Version:     0.0.4
 14 |  * Author:      pluginkollektiv
 15 |  * Author URI:  https://pluginkollektiv.org/
 16 |  * Text Domain: checksum-verifier
 17 |  * License:     GPLv2 or later
 18 |  *
 19 |  * Copyright (C)  2014-2015 Sergej Müller
 20 |  * Copyright (C)  2016-2017 pluginkollektiv
 21 |  *
 22 |  * Checksum Verifier is free software: you can redistribute it and/or modify
 23 |  * it under the terms of the GNU General Public License as published by
 24 |  * the Free Software Foundation, either version 2 of the License, or
 25 |  * any later version.
 26 |  *
 27 |  * Checksum Verifier is distributed in the hope that it will be useful,
 28 |  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 29 |  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 30 |  * GNU General Public License for more details.
 31 |  *
 32 |  * You should have received a copy of the GNU General Public License
 33 |  * along with Checksum Verifier. If not, see http://www.gnu.org/licenses/gpl-2.0.html.
 34 |  */
 35 | 
 36 | // Quit.
 37 | defined( 'ABSPATH' ) || exit;
 38 | 
 39 | 
 40 | // Constants.
 41 | define(
 42 | 	'CHECKSUM_VERIFIER_BASE',
 43 | 	plugin_basename( __FILE__ )
 44 | );
 45 | define(
 46 | 	'CHECKSUM_VERIFIER_CRON',
 47 | 	'checksum_verifier_verify_files'
 48 | );
 49 | 
 50 | 
 51 | // Register.
 52 | register_activation_hook(
 53 | 	__FILE__,
 54 | 	array(
 55 | 		'Checksum_Verifier',
 56 | 		'activation_hook',
 57 | 	)
 58 | );
 59 | register_deactivation_hook(
 60 | 	__FILE__,
 61 | 	array(
 62 | 		'Checksum_Verifier',
 63 | 		'deactivation_hook',
 64 | 	)
 65 | );
 66 | register_uninstall_hook(
 67 | 	__FILE__,
 68 | 	array(
 69 | 		'Checksum_Verifier',
 70 | 		'uninstall_hook',
 71 | 	)
 72 | );
 73 | 
 74 | // Hooks.
 75 | add_action(
 76 | 	CHECKSUM_VERIFIER_CRON,
 77 | 	array(
 78 | 		'Checksum_Verifier',
 79 | 		'verify_files',
 80 | 	)
 81 | );
 82 | add_filter(
 83 | 	'plugin_row_meta',
 84 | 	array(
 85 | 		'Checksum_Verifier',
 86 | 		'plugin_meta',
 87 | 	),
 88 | 	10,
 89 | 	2
 90 | );
 91 | 
 92 | add_action(
 93 | 	is_network_admin() ? 'network_admin_notices' : 'admin_notices',
 94 | 	array(
 95 | 		'Checksum_Verifier',
 96 | 		'add_deprecation_notice',
 97 | 	)
 98 | );
 99 | 
100 | // Autoload.
101 | require_once sprintf(
102 | 	'%s/inc/autoload.php',
103 | 	dirname( __FILE__ )
104 | );
105 | 


--------------------------------------------------------------------------------
/README.md:
--------------------------------------------------------------------------------
 1 | # Checksum Verifier #
 2 | Contributors:      pluginkollektiv  
 3 | Tags:              security, md5, hash, checksum, scan, malware, SoakSoak  
 4 | Donate link:       https://www.paypal.com/cgi-bin/webscr?cmd=_donations&business=TD4AMD2D8EMZW  
 5 | Requires at least: 3.8  
 6 | Tested up to:      5.6
 7 | Stable tag:        0.0.4  
 8 | License:           GPLv2 or later  
 9 | License URI:       http://www.gnu.org/licenses/gpl-2.0.html  
10 | 
11 | Verifies MD5 checksums of WordPress core files, sends e-mail to the mail address of your admin user warning in case of threat. Just activate it and you are done.
12 | 
13 | ## Description ##
14 | **Warning: *Checksum Verifier* has reached end of life. Its functionality is available in AntiVirus 1.4.0, use this plugin instead.**
15 | 
16 | *Checksum Verifier* calculates MD5 checksums for all existing WordPress core files and checks them against official checksums. It thus will detect and react upon any unrecognized modifications made on your WordPress core system (for example [SoakSoak malware](http://blog.sucuri.net/2014/12/soaksoak-malware-compromises-100000-wordpress-websites.html)).
17 | 
18 | *Checksum Verifier* runs a daily check on MD5 checksums. In case an unexpected result is detected in core, the plugin will send an e-mail with a list of affected files to site administrators (or super-admins in WordPress multisite). The first check-up will be executed during plugin activation. Regular core updates won’t cause any alarm, of course. Only in case core files have been compromised and your site might have been hacked, the plugin will notify you.
19 | 
20 | *Checksum Verifier* works as a "silent" background process and will only bother you in case of unexpected file modifications that could potentially threaten your core install.
21 | 
22 | Better security with WordPress.
23 | 
24 | ### Usable Hooks ###
25 | * `checksum_verifier_ignore_files`<br>
26 |  Modify or extend an `array` of file paths to be excluded from verification, relative to your WordPress installation path.<br>
27 |  Default is `array('wp-config-sample.php', 'wp-includes/version.php', 'readme.html', 'readme-ja.html', 'liesmich.html', 'olvasdel.html', 'procitajme.html')`.  
28 | 
29 | ### Support ###
30 | * Community support via the [support forums on wordpress.org](https://wordpress.org/support/plugin/checksum-verifier)
31 | * We don't handle support via e-mail, Twitter, GitHub issues etc.
32 | 
33 | ### Contribute ###
34 | * Active development of this plugin is handled [on GitHub](https://github.com/pluginkollektiv/checksum-verifier).
35 | * Pull requests for documented bugs are highly appreciated.
36 | * If you think you’ve found a bug (e.g. you’re experiencing unexpected behavior), please post at the [support forums](https://wordpress.org/support/plugin/checksum-verifier) first.
37 | * If you want to help us translate this plugin you can do so [on WordPress Translate](https://translate.wordpress.org/projects/wp-plugins/checksum-verifier).
38 | 
39 | ### Credits ###
40 | * Author: [Sergej Müller](https://sergejmueller.github.io/)
41 | * Maintainers: [pluginkollektiv](http://pluginkollektiv.org/)
42 | * English Translator: [Caspar Hübinger](http://glueckpress.com)
43 | * Russian Translator: [Sergej Müller](http://wpcoder.de)
44 | 
45 | ## Installation ##
46 | * If you don’t know how to install a plugin for WordPress, [here’s how](http://codex.wordpress.org/Managing_Plugins#Installing_Plugins).
47 | 
48 | ## Changelog ##
49 | 
50 | ### 0.0.4 ###
51 | * Deprecate plugin in favor of AntiVirus 1.4.0, which integrates Checksum Verifier functionality 
52 | 
53 | ### 0.0.3 ###
54 | * Remove `lang` folder in favor of the usage of translate.wordpress.org
55 | 
56 | ### 0.0.2 ###
57 | * `wp-content/` directory is excluded from verification
58 | * Localized readme.html files excluded from verification 
59 | * Minor code enhancements
60 | * Removed explicitly setting maximum execution time
61 | 
62 | ### 0.0.1 ###
63 | * *Checksum Verifier* goes live
64 | 


--------------------------------------------------------------------------------
/inc/class-checksum-verifier.php:
--------------------------------------------------------------------------------
  1 | <?php
  2 | /**
  3 |  * Checksum-Verifier: Main Class
  4 |  *
  5 |  * @package Checksum-Verifier
  6 |  * @since   0.0.1
  7 |  */
  8 | 
  9 | // Quit.
 10 | defined( 'ABSPATH' ) || exit;
 11 | 
 12 | 
 13 | /**
 14 |  * Checksum_Verifier
 15 |  *
 16 |  * @since    0.0.1
 17 |  */
 18 | class Checksum_Verifier {
 19 | 
 20 | 	/**
 21 | 	 * Perform the check
 22 | 	 *
 23 | 	 * @since   0.0.1
 24 | 	 */
 25 | 	public static function verify_files() {
 26 | 		// Get checksums via API.
 27 | 		$checksums = self::get_checksums();
 28 | 		if ( ! $checksums ) {
 29 | 			return;
 30 | 		}
 31 | 
 32 | 		// Loop files and match checksums.
 33 | 		$matches = self::match_checksums( $checksums );
 34 | 		if ( ! $matches ) {
 35 | 			return;
 36 | 		}
 37 | 
 38 | 		// Notification mail.
 39 | 		self::notify_admin( $matches );
 40 | 	}
 41 | 
 42 | 
 43 | 	/**
 44 | 	 * Get file checksums.
 45 | 	 *
 46 | 	 * @since   0.0.1
 47 | 	 *
 48 | 	 * @return  array  Checksums getting from API.
 49 | 	 */
 50 | 	private static function get_checksums() {
 51 | 		// Blog information.
 52 | 		$version  = get_bloginfo( 'version' );
 53 | 		$language = get_locale();
 54 | 
 55 | 		// Transient name.
 56 | 		$transient = sprintf(
 57 | 			'checksums_%s',
 58 | 			base64_encode( $version . $language )
 59 | 		);
 60 | 
 61 | 		// Read from cache.
 62 | 		$checksums = get_site_transient( $transient );
 63 | 		if ( $checksums ) {
 64 | 			return $checksums;
 65 | 		}
 66 | 
 67 | 		// Start API request.
 68 | 		$response = wp_remote_get(
 69 | 			add_query_arg(
 70 | 				array(
 71 | 					'version' => $version,
 72 | 					'locale'  => $language,
 73 | 				),
 74 | 				'https://api.wordpress.org/core/checksums/1.0/'
 75 | 			)
 76 | 		);
 77 | 
 78 | 		// Check response code.
 79 | 		if ( wp_remote_retrieve_response_code( $response ) !== 200 ) {
 80 | 			return;
 81 | 		}
 82 | 
 83 | 		// JSON magic.
 84 | 		$json = json_decode(
 85 | 			wp_remote_retrieve_body( $response )
 86 | 		);
 87 | 
 88 | 		// Exit on JSON error.
 89 | 		if ( json_last_error() !== JSON_ERROR_NONE ) {
 90 | 			return;
 91 | 		}
 92 | 
 93 | 		// Checksums exists?
 94 | 		if ( empty( $json->checksums ) ) {
 95 | 			return;
 96 | 		}
 97 | 
 98 | 		// Eat it.
 99 | 		$checksums = $json->checksums;
100 | 
101 | 		// Save into the cache.
102 | 		set_site_transient(
103 | 			$transient,
104 | 			$checksums,
105 | 			DAY_IN_SECONDS
106 | 		);
107 | 
108 | 		return $checksums;
109 | 	}
110 | 
111 | 
112 | 	/**
113 | 	 * Matching of MD5 hashes
114 | 	 *
115 | 	 * @since   0.0.1
116 | 	 *
117 | 	 * @hook    array  checksum_verifier_ignore_files
118 | 	 *
119 | 	 * @param   array $checksums File checksums.
120 | 	 * @return  array            File paths
121 | 	 */
122 | 	private static function match_checksums( $checksums ) {
123 | 		// Ignore files filter.
124 | 		$ignore_files = (array) apply_filters(
125 | 			'checksum_verifier_ignore_files',
126 | 			array(
127 | 				'wp-config-sample.php',
128 | 				'wp-includes/version.php',
129 | 				'readme.html',      // Default readme file.
130 | 				'readme-ja.html',   // Japanese readme, shipped up to 3.9 (ja).
131 | 				'liesmich.html',    // German readme (de_DE).
132 | 				'olvasdel.html',    // Hungarian readme (hu_HU).
133 | 				'procitajme.html',  // Croatian readme (hr).
134 | 			)
135 | 		);
136 | 
137 | 		// Init matches.
138 | 		$matches = array();
139 | 
140 | 		// Loop files.
141 | 		foreach ( $checksums as $file => $checksum ) {
142 | 			// Skip ignored files and wp-content directory.
143 | 			if ( 0 === strpos( $file, 'wp-content/' ) || in_array( $file, $ignore_files, true ) ) {
144 | 				continue;
145 | 			}
146 | 
147 | 			// File path.
148 | 			$file_path = ABSPATH . $file;
149 | 
150 | 			// File check.
151 | 			if ( 0 !== validate_file( $file_path ) || ! file_exists( $file_path ) ) {
152 | 				continue;
153 | 			}
154 | 
155 | 			// Compare MD5 hashes.
156 | 			if ( md5_file( $file_path ) !== $checksum ) {
157 | 				$matches[] = $file;
158 | 			}
159 | 		}
160 | 
161 | 		return $matches;
162 | 	}
163 | 
164 | 
165 | 	/**
166 | 	 * Admin notification mail.
167 | 	 *
168 | 	 * @since   0.0.1
169 | 	 *
170 | 	 * @param   array $matches File paths.
171 | 	 * @return  void
172 | 	 */
173 | 	private static function notify_admin( $matches ) {
174 | 		// Text domain on demand.
175 | 		load_plugin_textdomain( 'checksum-verifier' );
176 | 
177 | 		// Mail recipient.
178 | 		$to = get_bloginfo( 'admin_email' );
179 | 
180 | 		// Mail subject.
181 | 		$subject = wp_specialchars_decode(
182 | 			sprintf(
183 | 				'[%s] %s',
184 | 				get_bloginfo( 'name' ),
185 | 				esc_html__( 'Checksum Verifier Alert', 'checksum-verifier' )
186 | 			),
187 | 			ENT_QUOTES
188 | 		);
189 | 
190 | 		// Mail body.
191 | 		$body = wp_specialchars_decode(
192 | 			sprintf(
193 | 				"%s:\r\n\r\n- %s",
194 | 				esc_html__( 'Official checksums do not match for the following files', 'checksum-verifier' ),
195 | 				implode( "\r\n- ", $matches )
196 | 			),
197 | 			ENT_QUOTES
198 | 		);
199 | 
200 | 		// Send!
201 | 		wp_mail(
202 | 			$to,
203 | 			$subject,
204 | 			$body
205 | 		);
206 | 
207 | 		// Write to log.
208 | 		if ( defined( 'WP_DEBUG_LOG' ) && WP_DEBUG_LOG ) {
209 | 			// @codingStandardsIgnoreLine Ignore this call for now...
210 | 			error_log(
211 | 				sprintf(
212 | 					'%s: %s',
213 | 					esc_html__( 'Checksums do not match for the following files', 'checksum-verifier' ),
214 | 					implode( ', ', $matches )
215 | 				)
216 | 			);
217 | 		}
218 | 	}
219 | 
220 | 
221 | 	/**
222 | 	 * Plugin meta rows.
223 | 	 *
224 | 	 * @since   0.0.1
225 | 	 *
226 | 	 * @param   array  $input Exists plugin rows.
227 | 	 * @param   string $file  Current plugin file.
228 | 	 *
229 | 	 * @return  array         Extended plugin rows.
230 | 	 */
231 | 	public static function plugin_meta( $input, $file ) {
232 | 		// Skip other plugins.
233 | 		if ( CHECKSUM_VERIFIER_BASE !== $file ) {
234 | 			return $input;
235 | 		}
236 | 
237 | 		// Next update time.
238 | 		$timestamp = wp_next_scheduled( CHECKSUM_VERIFIER_CRON );
239 | 		if ( $timestamp ) {
240 | 			$scheduled = human_time_diff( time(), $timestamp );
241 | 		} else {
242 | 			$scheduled = esc_html( 'Never' );
243 | 		}
244 | 
245 | 		// Plugin rows.
246 | 		return array_merge(
247 | 			$input,
248 | 			array(
249 | 				'<a href="https://www.paypal.com/cgi-bin/webscr?cmd=_donations&business=TD4AMD2D8EMZW" target="_blank" rel="noopener noreferrer">' . esc_html__( 'Donate', 'checksum-verifier' ) . '</a>',
250 | 				'<a href="https://wordpress.org/support/plugin/checksum-verifier" target="_blank" rel="noopener noreferrer">' . esc_html__( 'Support', 'checksum-verifier' ) . '</a>',
251 | 				sprintf(
252 | 					'%s %s',
253 | 					esc_html__( 'Next check in', 'checksum-verifier' ),
254 | 					$scheduled
255 | 				),
256 | 			)
257 | 		);
258 | 	}
259 | 
260 | 
261 | 	/**
262 | 	 * Plugin activation hook.
263 | 	 *
264 | 	 * @since   0.0.1
265 | 	 */
266 | 	public static function activation_hook() {
267 | 		wp_schedule_event(
268 | 			time(),
269 | 			'daily',
270 | 			CHECKSUM_VERIFIER_CRON
271 | 		);
272 | 	}
273 | 
274 | 
275 | 	/**
276 | 	 * Plugin deactivation hook.
277 | 	 *
278 | 	 * @since   0.0.1
279 | 	 */
280 | 	public static function deactivation_hook() {
281 | 		wp_clear_scheduled_hook(
282 | 			CHECKSUM_VERIFIER_CRON
283 | 		);
284 | 	}
285 | 
286 | 
287 | 	/**
288 | 	 * Plugin uninstall hook.
289 | 	 *
290 | 	 * @since   0.0.1
291 | 	 */
292 | 	public static function uninstall_hook() {
293 | 		global $wpdb;
294 | 
295 | 		// Execute.
296 | 		$wpdb->query(
297 | 			$wpdb->prepare(
298 | 				"DELETE FROM $wpdb->options WHERE ( option_name LIKE (%s) OR option_name LIKE (%s) )",
299 | 				'%\\_transient\\_checksums%',
300 | 				'%\\_transient\\_timeout\\_checksums%'
301 | 			)
302 | 		);
303 | 	}
304 | 
305 | 	/**
306 | 	 * Add deprecation notice in WP Admin.
307 | 	 */
308 | 	public static function add_deprecation_notice() {
309 | 		$active = is_plugin_active( 'antivirus/antivirus.php' );
310 | 		?>
311 | 		<div class="notice notice-warning">
312 | 			<p><?php esc_html_e( 'Checksum Verifier is deprecated. Its functionality is integrated into AntiVirus now.', 'checksum-verifier' ); ?></p>
313 | 			<p><?php esc_html_e( 'Switch to AntiVirus now:', 'checksum-verifier ' ); ?></p>
314 | 			<ol>
315 | 				<li><?php esc_html_e( 'Install and activate AntiVirus 1.4.0+.', 'checksum-verifier' ); ?>
316 | 					<?php
317 | 					if ( ! $active ) {
318 | 							$install_url = add_query_arg(
319 | 								array(
320 | 									's' => 'pluginkollektiv',
321 | 									'tab' => 'search',
322 | 									'type' => 'author',
323 | 								),
324 | 								admin_url( '/plugin-install.php' )
325 | 							);
326 | 						?>
327 | 						<a href="<?php echo esc_attr( $install_url ); ?>">
328 | 							<?php esc_html_e( 'Install now.', 'checksum-verifier' ); ?>
329 | 						</a>
330 | 					<?php } ?>
331 | 				</li>
332 | 				<li><?php esc_html_e( 'Enable option "Checksum verification of WP core files".', 'checksum-verifier' ); ?>
333 | 					<?php
334 | 					if ( $active ) {
335 | 							$options_url = add_query_arg(
336 | 								array(
337 | 									'page' => 'antivirus',
338 | 								),
339 | 								admin_url( '/options-general.php' )
340 | 							);
341 | 						?>
342 | 						<a href="<?php echo esc_attr( $options_url ); ?>">
343 | 							<?php esc_html_e( 'Go to AntiVirus settings.', 'checksum-verifier' ); ?>
344 | 						</a>
345 | 					<?php } ?>
346 | 				</li>
347 | 				<li><?php esc_html_e( 'Deactivate and uninstall Checksum Verifier.', 'checksum-verifier' ); ?></li>
348 | 			</ol>
349 | 		</div>
350 | 		<?php
351 | 	}
352 | }
353 | 


--------------------------------------------------------------------------------
/LICENSE.txt:
--------------------------------------------------------------------------------
  1 |                     GNU GENERAL PUBLIC LICENSE
  2 |                        Version 2, June 1991
  3 | 
  4 |  Copyright (C) 1989, 1991 Free Software Foundation, Inc., <http://fsf.org/>
  5 |  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  6 |  Everyone is permitted to copy and distribute verbatim copies
  7 |  of this license document, but changing it is not allowed.
  8 | 
  9 |                             Preamble
 10 | 
 11 |   The licenses for most software are designed to take away your
 12 | freedom to share and change it.  By contrast, the GNU General Public
 13 | License is intended to guarantee your freedom to share and change free
 14 | software--to make sure the software is free for all its users.  This
 15 | General Public License applies to most of the Free Software
 16 | Foundation's software and to any other program whose authors commit to
 17 | using it.  (Some other Free Software Foundation software is covered by
 18 | the GNU Lesser General Public License instead.)  You can apply it to
 19 | your programs, too.
 20 | 
 21 |   When we speak of free software, we are referring to freedom, not
 22 | price.  Our General Public Licenses are designed to make sure that you
 23 | have the freedom to distribute copies of free software (and charge for
 24 | this service if you wish), that you receive source code or can get it
 25 | if you want it, that you can change the software or use pieces of it
 26 | in new free programs; and that you know you can do these things.
 27 | 
 28 |   To protect your rights, we need to make restrictions that forbid
 29 | anyone to deny you these rights or to ask you to surrender the rights.
 30 | These restrictions translate to certain responsibilities for you if you
 31 | distribute copies of the software, or if you modify it.
 32 | 
 33 |   For example, if you distribute copies of such a program, whether
 34 | gratis or for a fee, you must give the recipients all the rights that
 35 | you have.  You must make sure that they, too, receive or can get the
 36 | source code.  And you must show them these terms so they know their
 37 | rights.
 38 | 
 39 |   We protect your rights with two steps: (1) copyright the software, and
 40 | (2) offer you this license which gives you legal permission to copy,
 41 | distribute and/or modify the software.
 42 | 
 43 |   Also, for each author's protection and ours, we want to make certain
 44 | that everyone understands that there is no warranty for this free
 45 | software.  If the software is modified by someone else and passed on, we
 46 | want its recipients to know that what they have is not the original, so
 47 | that any problems introduced by others will not reflect on the original
 48 | authors' reputations.
 49 | 
 50 |   Finally, any free program is threatened constantly by software
 51 | patents.  We wish to avoid the danger that redistributors of a free
 52 | program will individually obtain patent licenses, in effect making the
 53 | program proprietary.  To prevent this, we have made it clear that any
 54 | patent must be licensed for everyone's free use or not licensed at all.
 55 | 
 56 |   The precise terms and conditions for copying, distribution and
 57 | modification follow.
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 59 |                     GNU GENERAL PUBLIC LICENSE
 60 |    TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
 61 | 
 62 |   0. This License applies to any program or other work which contains
 63 | a notice placed by the copyright holder saying it may be distributed
 64 | under the terms of this General Public License.  The "Program", below,
 65 | refers to any such program or work, and a "work based on the Program"
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 67 | that is to say, a work containing the Program or a portion of it,
 68 | either verbatim or with modifications and/or translated into another
 69 | language.  (Hereinafter, translation is included without limitation in
 70 | the term "modification".)  Each licensee is addressed as "you".
 71 | 
 72 | Activities other than copying, distribution and modification are not
 73 | covered by this License; they are outside its scope.  The act of
 74 | running the Program is not restricted, and the output from the Program
 75 | is covered only if its contents constitute a work based on the
 76 | Program (independent of having been made by running the Program).
 77 | Whether that is true depends on what the Program does.
 78 | 
 79 |   1. You may copy and distribute verbatim copies of the Program's
 80 | source code as you receive it, in any medium, provided that you
 81 | conspicuously and appropriately publish on each copy an appropriate
 82 | copyright notice and disclaimer of warranty; keep intact all the
 83 | notices that refer to this License and to the absence of any warranty;
 84 | and give any other recipients of the Program a copy of this License
 85 | along with the Program.
 86 | 
 87 | You may charge a fee for the physical act of transferring a copy, and
 88 | you may at your option offer warranty protection in exchange for a fee.
 89 | 
 90 |   2. You may modify your copy or copies of the Program or any portion
 91 | of it, thus forming a work based on the Program, and copy and
 92 | distribute such modifications or work under the terms of Section 1
 93 | above, provided that you also meet all of these conditions:
 94 | 
 95 |     a) You must cause the modified files to carry prominent notices
 96 |     stating that you changed the files and the date of any change.
 97 | 
 98 |     b) You must cause any work that you distribute or publish, that in
 99 |     whole or in part contains or is derived from the Program or any
100 |     part thereof, to be licensed as a whole at no charge to all third
101 |     parties under the terms of this License.
102 | 
103 |     c) If the modified program normally reads commands interactively
104 |     when run, you must cause it, when started running for such
105 |     interactive use in the most ordinary way, to print or display an
106 |     announcement including an appropriate copyright notice and a
107 |     notice that there is no warranty (or else, saying that you provide
108 |     a warranty) and that users may redistribute the program under
109 |     these conditions, and telling the user how to view a copy of this
110 |     License.  (Exception: if the Program itself is interactive but
111 |     does not normally print such an announcement, your work based on
112 |     the Program is not required to print an announcement.)
113 | 
114 | These requirements apply to the modified work as a whole.  If
115 | identifiable sections of that work are not derived from the Program,
116 | and can be reasonably considered independent and separate works in
117 | themselves, then this License, and its terms, do not apply to those
118 | sections when you distribute them as separate works.  But when you
119 | distribute the same sections as part of a whole which is a work based
120 | on the Program, the distribution of the whole must be on the terms of
121 | this License, whose permissions for other licensees extend to the
122 | entire whole, and thus to each and every part regardless of who wrote it.
123 | 
124 | Thus, it is not the intent of this section to claim rights or contest
125 | your rights to work written entirely by you; rather, the intent is to
126 | exercise the right to control the distribution of derivative or
127 | collective works based on the Program.
128 | 
129 | In addition, mere aggregation of another work not based on the Program
130 | with the Program (or with a work based on the Program) on a volume of
131 | a storage or distribution medium does not bring the other work under
132 | the scope of this License.
133 | 
134 |   3. You may copy and distribute the Program (or a work based on it,
135 | under Section 2) in object code or executable form under the terms of
136 | Sections 1 and 2 above provided that you also do one of the following:
137 | 
138 |     a) Accompany it with the complete corresponding machine-readable
139 |     source code, which must be distributed under the terms of Sections
140 |     1 and 2 above on a medium customarily used for software interchange; or,
141 | 
142 |     b) Accompany it with a written offer, valid for at least three
143 |     years, to give any third party, for a charge no more than your
144 |     cost of physically performing source distribution, a complete
145 |     machine-readable copy of the corresponding source code, to be
146 |     distributed under the terms of Sections 1 and 2 above on a medium
147 |     customarily used for software interchange; or,
148 | 
149 |     c) Accompany it with the information you received as to the offer
150 |     to distribute corresponding source code.  (This alternative is
151 |     allowed only for noncommercial distribution and only if you
152 |     received the program in object code or executable form with such
153 |     an offer, in accord with Subsection b above.)
154 | 
155 | The source code for a work means the preferred form of the work for
156 | making modifications to it.  For an executable work, complete source
157 | code means all the source code for all modules it contains, plus any
158 | associated interface definition files, plus the scripts used to
159 | control compilation and installation of the executable.  However, as a
160 | special exception, the source code distributed need not include
161 | anything that is normally distributed (in either source or binary
162 | form) with the major components (compiler, kernel, and so on) of the
163 | operating system on which the executable runs, unless that component
164 | itself accompanies the executable.
165 | 
166 | If distribution of executable or object code is made by offering
167 | access to copy from a designated place, then offering equivalent
168 | access to copy the source code from the same place counts as
169 | distribution of the source code, even though third parties are not
170 | compelled to copy the source along with the object code.
171 | 
172 |   4. You may not copy, modify, sublicense, or distribute the Program
173 | except as expressly provided under this License.  Any attempt
174 | otherwise to copy, modify, sublicense or distribute the Program is
175 | void, and will automatically terminate your rights under this License.
176 | However, parties who have received copies, or rights, from you under
177 | this License will not have their licenses terminated so long as such
178 | parties remain in full compliance.
179 | 
180 |   5. You are not required to accept this License, since you have not
181 | signed it.  However, nothing else grants you permission to modify or
182 | distribute the Program or its derivative works.  These actions are
183 | prohibited by law if you do not accept this License.  Therefore, by
184 | modifying or distributing the Program (or any work based on the
185 | Program), you indicate your acceptance of this License to do so, and
186 | all its terms and conditions for copying, distributing or modifying
187 | the Program or works based on it.
188 | 
189 |   6. Each time you redistribute the Program (or any work based on the
190 | Program), the recipient automatically receives a license from the
191 | original licensor to copy, distribute or modify the Program subject to
192 | these terms and conditions.  You may not impose any further
193 | restrictions on the recipients' exercise of the rights granted herein.
194 | You are not responsible for enforcing compliance by third parties to
195 | this License.
196 | 
197 |   7. If, as a consequence of a court judgment or allegation of patent
198 | infringement or for any other reason (not limited to patent issues),
199 | conditions are imposed on you (whether by court order, agreement or
200 | otherwise) that contradict the conditions of this License, they do not
201 | excuse you from the conditions of this License.  If you cannot
202 | distribute so as to satisfy simultaneously your obligations under this
203 | License and any other pertinent obligations, then as a consequence you
204 | may not distribute the Program at all.  For example, if a patent
205 | license would not permit royalty-free redistribution of the Program by
206 | all those who receive copies directly or indirectly through you, then
207 | the only way you could satisfy both it and this License would be to
208 | refrain entirely from distribution of the Program.
209 | 
210 | If any portion of this section is held invalid or unenforceable under
211 | any particular circumstance, the balance of the section is intended to
212 | apply and the section as a whole is intended to apply in other
213 | circumstances.
214 | 
215 | It is not the purpose of this section to induce you to infringe any
216 | patents or other property right claims or to contest validity of any
217 | such claims; this section has the sole purpose of protecting the
218 | integrity of the free software distribution system, which is
219 | implemented by public license practices.  Many people have made
220 | generous contributions to the wide range of software distributed
221 | through that system in reliance on consistent application of that
222 | system; it is up to the author/donor to decide if he or she is willing
223 | to distribute software through any other system and a licensee cannot
224 | impose that choice.
225 | 
226 | This section is intended to make thoroughly clear what is believed to
227 | be a consequence of the rest of this License.
228 | 
229 |   8. If the distribution and/or use of the Program is restricted in
230 | certain countries either by patents or by copyrighted interfaces, the
231 | original copyright holder who places the Program under this License
232 | may add an explicit geographical distribution limitation excluding
233 | those countries, so that distribution is permitted only in or among
234 | countries not thus excluded.  In such case, this License incorporates
235 | the limitation as if written in the body of this License.
236 | 
237 |   9. The Free Software Foundation may publish revised and/or new versions
238 | of the General Public License from time to time.  Such new versions will
239 | be similar in spirit to the present version, but may differ in detail to
240 | address new problems or concerns.
241 | 
242 | Each version is given a distinguishing version number.  If the Program
243 | specifies a version number of this License which applies to it and "any
244 | later version", you have the option of following the terms and conditions
245 | either of that version or of any later version published by the Free
246 | Software Foundation.  If the Program does not specify a version number of
247 | this License, you may choose any version ever published by the Free Software
248 | Foundation.
249 | 
250 |   10. If you wish to incorporate parts of the Program into other free
251 | programs whose distribution conditions are different, write to the author
252 | to ask for permission.  For software which is copyrighted by the Free
253 | Software Foundation, write to the Free Software Foundation; we sometimes
254 | make exceptions for this.  Our decision will be guided by the two goals
255 | of preserving the free status of all derivatives of our free software and
256 | of promoting the sharing and reuse of software generally.
257 | 
258 |                             NO WARRANTY
259 | 
260 |   11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
261 | FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
262 | OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
263 | PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
264 | OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
265 | MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS
266 | TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE
267 | PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
268 | REPAIR OR CORRECTION.
269 | 
270 |   12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
271 | WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
272 | REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
273 | INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
274 | OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
275 | TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
276 | YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
277 | PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
278 | POSSIBILITY OF SUCH DAMAGES.
279 | 
280 |                      END OF TERMS AND CONDITIONS
281 | 
282 |             How to Apply These Terms to Your New Programs
283 | 
284 |   If you develop a new program, and you want it to be of the greatest
285 | possible use to the public, the best way to achieve this is to make it
286 | free software which everyone can redistribute and change under these terms.
287 | 
288 |   To do so, attach the following notices to the program.  It is safest
289 | to attach them to the start of each source file to most effectively
290 | convey the exclusion of warranty; and each file should have at least
291 | the "copyright" line and a pointer to where the full notice is found.
292 | 
293 |     {description}
294 |     Copyright (C) {year}  {fullname}
295 | 
296 |     This program is free software; you can redistribute it and/or modify
297 |     it under the terms of the GNU General Public License as published by
298 |     the Free Software Foundation; either version 2 of the License, or
299 |     (at your option) any later version.
300 | 
301 |     This program is distributed in the hope that it will be useful,
302 |     but WITHOUT ANY WARRANTY; without even the implied warranty of
303 |     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
304 |     GNU General Public License for more details.
305 | 
306 |     You should have received a copy of the GNU General Public License along
307 |     with this program; if not, write to the Free Software Foundation, Inc.,
308 |     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
309 | 
310 | Also add information on how to contact you by electronic and paper mail.
311 | 
312 | If the program is interactive, make it output a short notice like this
313 | when it starts in an interactive mode:
314 | 
315 |     Gnomovision version 69, Copyright (C) year name of author
316 |     Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
317 |     This is free software, and you are welcome to redistribute it
318 |     under certain conditions; type `show c' for details.
319 | 
320 | The hypothetical commands `show w' and `show c' should show the appropriate
321 | parts of the General Public License.  Of course, the commands you use may
322 | be called something other than `show w' and `show c'; they could even be
323 | mouse-clicks or menu items--whatever suits your program.
324 | 
325 | You should also get your employer (if you work as a programmer) or your
326 | school, if any, to sign a "copyright disclaimer" for the program, if
327 | necessary.  Here is a sample; alter the names:
328 | 
329 |   Yoyodyne, Inc., hereby disclaims all copyright interest in the program
330 |   `Gnomovision' (which makes passes at compilers) written by James Hacker.
331 | 
332 |   {signature of Ty Coon}, 1 April 1989
333 |   Ty Coon, President of Vice
334 | 
335 | This General Public License does not permit incorporating your program into
336 | proprietary programs.  If your program is a subroutine library, you may
337 | consider it more useful to permit linking proprietary applications with the
338 | library.  If this is what you want to do, use the GNU Lesser General
339 | Public License instead of this License.
340 | 


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