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2809 rexy 1
<?php
2
/**
3
 * Smarty plugin
4
 *
5
 * @package    Smarty
6
 * @subpackage Security
7
 * @author     Uwe Tews
8
 */
9
/**
10
 * FIXME: Smarty_Security API
11
 *      - getter and setter instead of public properties would allow cultivating an internal cache properly
12
 *      - current implementation of isTrustedResourceDir() assumes that Smarty::$template_dir and Smarty::$config_dir
13
 *      are immutable the cache is killed every time either of the variables change. That means that two distinct
14
 *      Smarty objects with differing
15
 *        $template_dir or $config_dir should NOT share the same Smarty_Security instance,
16
 *        as this would lead to (severe) performance penalty! how should this be handled?
17
 */
18
 
19
/**
20
 * This class does contain the security settings
21
 */
22
class Smarty_Security
23
{
24
    /**
25
     * This determines how Smarty handles "<?php ... ?>" tags in templates.
26
     * possible values:
27
     * <ul>
28
     *   <li>Smarty::PHP_PASSTHRU -> echo PHP tags as they are</li>
29
     *   <li>Smarty::PHP_QUOTE    -> escape tags as entities</li>
30
     *   <li>Smarty::PHP_REMOVE   -> remove php tags</li>
31
     *   <li>Smarty::PHP_ALLOW    -> execute php tags</li>
32
     * </ul>
33
     *
34
     * @var integer
35
     */
36
    public $php_handling = Smarty::PHP_PASSTHRU;
37
 
38
    /**
39
     * This is the list of template directories that are considered secure.
40
     * $template_dir is in this list implicitly.
41
     *
42
     * @var array
43
     */
44
    public $secure_dir = array();
45
 
46
    /**
47
     * This is an array of directories where trusted php scripts reside.
48
     * {@link $security} is disabled during their inclusion/execution.
49
     *
50
     * @var array
51
     */
52
    public $trusted_dir = array();
53
 
54
    /**
55
     * List of regular expressions (PCRE) that include trusted URIs
56
     *
57
     * @var array
58
     */
59
    public $trusted_uri = array();
60
 
61
    /**
62
     * List of trusted constants names
63
     *
64
     * @var array
65
     */
66
    public $trusted_constants = array();
67
 
68
    /**
69
     * This is an array of trusted static classes.
70
     * If empty access to all static classes is allowed.
71
     * If set to 'none' none is allowed.
72
     *
73
     * @var array
74
     */
75
    public $static_classes = array();
76
 
77
    /**
78
     * This is an nested array of trusted classes and static methods.
79
     * If empty access to all static classes and methods is allowed.
80
     * Format:
81
     * array (
82
     *         'class_1' => array('method_1', 'method_2'), // allowed methods listed
83
     *         'class_2' => array(),                       // all methods of class allowed
84
     *       )
85
     * If set to null none is allowed.
86
     *
87
     * @var array
88
     */
89
    public $trusted_static_methods = array();
90
 
91
    /**
92
     * This is an array of trusted static properties.
93
     * If empty access to all static classes and properties is allowed.
94
     * Format:
95
     * array (
96
     *         'class_1' => array('prop_1', 'prop_2'), // allowed properties listed
97
     *         'class_2' => array(),                   // all properties of class allowed
98
     *       )
99
     * If set to null none is allowed.
100
     *
101
     * @var array
102
     */
103
    public $trusted_static_properties = array();
104
 
105
    /**
106
     * This is an array of trusted PHP functions.
107
     * If empty all functions are allowed.
108
     * To disable all PHP functions set $php_functions = null.
109
     *
110
     * @var array
111
     */
112
    public $php_functions = array('isset', 'empty', 'count', 'sizeof', 'in_array', 'is_array', 'time',);
113
 
114
    /**
115
     * This is an array of trusted PHP modifiers.
116
     * If empty all modifiers are allowed.
117
     * To disable all modifier set $php_modifiers = null.
118
     *
119
     * @var array
120
     */
121
    public $php_modifiers = array('escape', 'count', 'nl2br',);
122
 
123
    /**
124
     * This is an array of allowed tags.
125
     * If empty no restriction by allowed_tags.
126
     *
127
     * @var array
128
     */
129
    public $allowed_tags = array();
130
 
131
    /**
132
     * This is an array of disabled tags.
133
     * If empty no restriction by disabled_tags.
134
     *
135
     * @var array
136
     */
137
    public $disabled_tags = array();
138
 
139
    /**
140
     * This is an array of allowed modifier plugins.
141
     * If empty no restriction by allowed_modifiers.
142
     *
143
     * @var array
144
     */
145
    public $allowed_modifiers = array();
146
 
147
    /**
148
     * This is an array of disabled modifier plugins.
149
     * If empty no restriction by disabled_modifiers.
150
     *
151
     * @var array
152
     */
153
    public $disabled_modifiers = array();
154
 
155
    /**
156
     * This is an array of disabled special $smarty variables.
157
     *
158
     * @var array
159
     */
160
    public $disabled_special_smarty_vars = array();
161
 
162
    /**
163
     * This is an array of trusted streams.
164
     * If empty all streams are allowed.
165
     * To disable all streams set $streams = null.
166
     *
167
     * @var array
168
     */
169
    public $streams = array('file');
170
 
171
    /**
172
     * + flag if constants can be accessed from template
173
     *
174
     * @var boolean
175
     */
176
    public $allow_constants = true;
177
 
178
    /**
179
     * + flag if super globals can be accessed from template
180
     *
181
     * @var boolean
182
     */
183
    public $allow_super_globals = true;
184
 
185
    /**
186
     * max template nesting level
187
     *
188
     * @var int
189
     */
190
    public $max_template_nesting = 0;
191
 
192
    /**
193
     * current template nesting level
194
     *
195
     * @var int
196
     */
197
    private $_current_template_nesting = 0;
198
 
199
    /**
200
     * Cache for $resource_dir lookup
201
     *
202
     * @var array
203
     */
204
    protected $_resource_dir = array();
205
 
206
    /**
207
     * Cache for $template_dir lookup
208
     *
209
     * @var array
210
     */
211
    protected $_template_dir = array();
212
 
213
    /**
214
     * Cache for $config_dir lookup
215
     *
216
     * @var array
217
     */
218
    protected $_config_dir = array();
219
 
220
    /**
221
     * Cache for $secure_dir lookup
222
     *
223
     * @var array
224
     */
225
    protected $_secure_dir = array();
226
 
227
    /**
228
     * Cache for $php_resource_dir lookup
229
     *
230
     * @var array
231
     */
232
    protected $_php_resource_dir = null;
233
 
234
    /**
235
     * Cache for $trusted_dir lookup
236
     *
237
     * @var array
238
     */
239
    protected $_trusted_dir = null;
240
 
241
    /**
242
     * Cache for include path status
243
     *
244
     * @var bool
245
     */
246
    protected $_include_path_status = false;
247
 
248
    /**
249
     * Cache for $_include_array lookup
250
     *
251
     * @var array
252
     */
253
    protected $_include_dir = array();
254
 
255
    /**
256
     * @param Smarty $smarty
257
     */
258
    public function __construct($smarty)
259
    {
260
        $this->smarty = $smarty;
261
    }
262
 
263
    /**
264
     * Check if PHP function is trusted.
265
     *
266
     * @param string $function_name
267
     * @param object $compiler compiler object
268
     *
269
     * @return boolean                 true if function is trusted
270
     */
271
    public function isTrustedPhpFunction($function_name, $compiler)
272
    {
273
        if (isset($this->php_functions)
274
            && (empty($this->php_functions) || in_array($function_name, $this->php_functions))
275
        ) {
276
            return true;
277
        }
278
        $compiler->trigger_template_error("PHP function '{$function_name}' not allowed by security setting");
279
        return false; // should not, but who knows what happens to the compiler in the future?
280
    }
281
 
282
    /**
283
     * Check if static class is trusted.
284
     *
285
     * @param string $class_name
286
     * @param object $compiler compiler object
287
     *
288
     * @return boolean                 true if class is trusted
289
     */
290
    public function isTrustedStaticClass($class_name, $compiler)
291
    {
292
        if (isset($this->static_classes)
293
            && (empty($this->static_classes) || in_array($class_name, $this->static_classes))
294
        ) {
295
            return true;
296
        }
297
        $compiler->trigger_template_error("access to static class '{$class_name}' not allowed by security setting");
298
        return false; // should not, but who knows what happens to the compiler in the future?
299
    }
300
 
301
    /**
302
     * Check if static class method/property is trusted.
303
     *
304
     * @param string $class_name
305
     * @param string $params
306
     * @param object $compiler compiler object
307
     *
308
     * @return boolean                 true if class method is trusted
309
     */
310
    public function isTrustedStaticClassAccess($class_name, $params, $compiler)
311
    {
312
        if (!isset($params[ 2 ])) {
313
            // fall back
314
            return $this->isTrustedStaticClass($class_name, $compiler);
315
        }
316
        if ($params[ 2 ] === 'method') {
317
            $allowed = $this->trusted_static_methods;
318
            $name = substr($params[ 0 ], 0, strpos($params[ 0 ], '('));
319
        } else {
320
            $allowed = $this->trusted_static_properties;
321
            // strip '$'
322
            $name = substr($params[ 0 ], 1);
323
        }
324
        if (isset($allowed)) {
325
            if (empty($allowed)) {
326
                // fall back
327
                return $this->isTrustedStaticClass($class_name, $compiler);
328
            }
329
            if (isset($allowed[ $class_name ])
330
                && (empty($allowed[ $class_name ]) || in_array($name, $allowed[ $class_name ]))
331
            ) {
332
                return true;
333
            }
334
        }
335
        $compiler->trigger_template_error("access to static class '{$class_name}' {$params[2]} '{$name}' not allowed by security setting");
336
        return false; // should not, but who knows what happens to the compiler in the future?
337
    }
338
 
339
    /**
340
     * Check if PHP modifier is trusted.
341
     *
342
     * @param string $modifier_name
343
     * @param object $compiler compiler object
344
     *
345
     * @return boolean                 true if modifier is trusted
346
     */
347
    public function isTrustedPhpModifier($modifier_name, $compiler)
348
    {
349
        if (isset($this->php_modifiers)
350
            && (empty($this->php_modifiers) || in_array($modifier_name, $this->php_modifiers))
351
        ) {
352
            return true;
353
        }
354
        $compiler->trigger_template_error("modifier '{$modifier_name}' not allowed by security setting");
355
        return false; // should not, but who knows what happens to the compiler in the future?
356
    }
357
 
358
    /**
359
     * Check if tag is trusted.
360
     *
361
     * @param string $tag_name
362
     * @param object $compiler compiler object
363
     *
364
     * @return boolean                 true if tag is trusted
365
     */
366
    public function isTrustedTag($tag_name, $compiler)
367
    {
368
        // check for internal always required tags
369
        if (in_array(
370
            $tag_name,
371
            array(
372
                'assign', 'call', 'private_filter', 'private_block_plugin', 'private_function_plugin',
373
                'private_object_block_function', 'private_object_function', 'private_registered_function',
374
                'private_registered_block', 'private_special_variable', 'private_print_expression',
375
                'private_modifier'
376
            )
377
        )
378
        ) {
379
            return true;
380
        }
381
        // check security settings
382
        if (empty($this->allowed_tags)) {
383
            if (empty($this->disabled_tags) || !in_array($tag_name, $this->disabled_tags)) {
384
                return true;
385
            } else {
386
                $compiler->trigger_template_error("tag '{$tag_name}' disabled by security setting", null, true);
387
            }
388
        } elseif (in_array($tag_name, $this->allowed_tags) && !in_array($tag_name, $this->disabled_tags)) {
389
            return true;
390
        } else {
391
            $compiler->trigger_template_error("tag '{$tag_name}' not allowed by security setting", null, true);
392
        }
393
        return false; // should not, but who knows what happens to the compiler in the future?
394
    }
395
 
396
    /**
397
     * Check if special $smarty variable is trusted.
398
     *
399
     * @param string $var_name
400
     * @param object $compiler compiler object
401
     *
402
     * @return boolean                 true if tag is trusted
403
     */
404
    public function isTrustedSpecialSmartyVar($var_name, $compiler)
405
    {
406
        if (!in_array($var_name, $this->disabled_special_smarty_vars)) {
407
            return true;
408
        } else {
409
            $compiler->trigger_template_error(
410
                "special variable '\$smarty.{$var_name}' not allowed by security setting",
411
                null,
412
                true
413
            );
414
        }
415
        return false; // should not, but who knows what happens to the compiler in the future?
416
    }
417
 
418
    /**
419
     * Check if modifier plugin is trusted.
420
     *
421
     * @param string $modifier_name
422
     * @param object $compiler compiler object
423
     *
424
     * @return boolean                 true if tag is trusted
425
     */
426
    public function isTrustedModifier($modifier_name, $compiler)
427
    {
428
        // check for internal always allowed modifier
429
        if (in_array($modifier_name, array('default'))) {
430
            return true;
431
        }
432
        // check security settings
433
        if (empty($this->allowed_modifiers)) {
434
            if (empty($this->disabled_modifiers) || !in_array($modifier_name, $this->disabled_modifiers)) {
435
                return true;
436
            } else {
437
                $compiler->trigger_template_error(
438
                    "modifier '{$modifier_name}' disabled by security setting",
439
                    null,
440
                    true
441
                );
442
            }
443
        } elseif (in_array($modifier_name, $this->allowed_modifiers)
444
                  && !in_array($modifier_name, $this->disabled_modifiers)
445
        ) {
446
            return true;
447
        } else {
448
            $compiler->trigger_template_error(
449
                "modifier '{$modifier_name}' not allowed by security setting",
450
                null,
451
                true
452
            );
453
        }
454
        return false; // should not, but who knows what happens to the compiler in the future?
455
    }
456
 
457
    /**
458
     * Check if constants are enabled or trusted
459
     *
460
     * @param string $const    constant name
461
     * @param object $compiler compiler object
462
     *
463
     * @return bool
464
     */
465
    public function isTrustedConstant($const, $compiler)
466
    {
467
        if (in_array($const, array('true', 'false', 'null'))) {
468
            return true;
469
        }
470
        if (!empty($this->trusted_constants)) {
471
            if (!in_array(strtolower($const), $this->trusted_constants)) {
472
                $compiler->trigger_template_error("Security: access to constant '{$const}' not permitted");
473
                return false;
474
            }
475
            return true;
476
        }
477
        if ($this->allow_constants) {
478
            return true;
479
        }
480
        $compiler->trigger_template_error("Security: access to constants not permitted");
481
        return false;
482
    }
483
 
484
    /**
485
     * Check if stream is trusted.
486
     *
487
     * @param string $stream_name
488
     *
489
     * @return boolean         true if stream is trusted
490
     * @throws SmartyException if stream is not trusted
491
     */
492
    public function isTrustedStream($stream_name)
493
    {
494
        if (isset($this->streams) && (empty($this->streams) || in_array($stream_name, $this->streams))) {
495
            return true;
496
        }
497
        throw new SmartyException("stream '{$stream_name}' not allowed by security setting");
498
    }
499
 
500
    /**
501
     * Check if directory of file resource is trusted.
502
     *
503
     * @param string    $filepath
504
     * @param null|bool $isConfig
505
     *
506
     * @return bool true if directory is trusted
507
     * @throws \SmartyException if directory is not trusted
508
     */
509
    public function isTrustedResourceDir($filepath, $isConfig = null)
510
    {
511
        if ($this->_include_path_status !== $this->smarty->use_include_path) {
512
            $_dir =
513
                $this->smarty->use_include_path ? $this->smarty->ext->_getIncludePath->getIncludePathDirs($this->smarty) : array();
514
            if ($this->_include_dir !== $_dir) {
515
                $this->_updateResourceDir($this->_include_dir, $_dir);
516
                $this->_include_dir = $_dir;
517
            }
518
            $this->_include_path_status = $this->smarty->use_include_path;
519
        }
520
        $_dir = $this->smarty->getTemplateDir();
521
        if ($this->_template_dir !== $_dir) {
522
            $this->_updateResourceDir($this->_template_dir, $_dir);
523
            $this->_template_dir = $_dir;
524
        }
525
        $_dir = $this->smarty->getConfigDir();
526
        if ($this->_config_dir !== $_dir) {
527
            $this->_updateResourceDir($this->_config_dir, $_dir);
528
            $this->_config_dir = $_dir;
529
        }
530
        if ($this->_secure_dir !== $this->secure_dir) {
531
            $this->secure_dir = (array)$this->secure_dir;
532
            foreach ($this->secure_dir as $k => $d) {
533
                $this->secure_dir[ $k ] = $this->smarty->_realpath($d . DIRECTORY_SEPARATOR, true);
534
            }
535
            $this->_updateResourceDir($this->_secure_dir, $this->secure_dir);
536
            $this->_secure_dir = $this->secure_dir;
537
        }
538
        $addPath = $this->_checkDir($filepath, $this->_resource_dir);
539
        if ($addPath !== false) {
540
            $this->_resource_dir = array_merge($this->_resource_dir, $addPath);
541
        }
542
        return true;
543
    }
544
 
545
    /**
546
     * Check if URI (e.g. {fetch} or {html_image}) is trusted
547
     * To simplify things, isTrustedUri() resolves all input to "{$PROTOCOL}://{$HOSTNAME}".
548
     * So "http://username:password@hello.world.example.org:8080/some-path?some=query-string"
549
     * is reduced to "http://hello.world.example.org" prior to applying the patters from {@link $trusted_uri}.
550
     *
551
     * @param string $uri
552
     *
553
     * @return boolean         true if URI is trusted
554
     * @throws SmartyException if URI is not trusted
555
     * @uses   $trusted_uri for list of patterns to match against $uri
556
     */
557
    public function isTrustedUri($uri)
558
    {
559
        $_uri = parse_url($uri);
560
        if (!empty($_uri[ 'scheme' ]) && !empty($_uri[ 'host' ])) {
561
            $_uri = $_uri[ 'scheme' ] . '://' . $_uri[ 'host' ];
562
            foreach ($this->trusted_uri as $pattern) {
563
                if (preg_match($pattern, $_uri)) {
564
                    return true;
565
                }
566
            }
567
        }
568
        throw new SmartyException("URI '{$uri}' not allowed by security setting");
569
    }
570
 
571
    /**
572
     * Check if directory of file resource is trusted.
573
     *
574
     * @param string $filepath
575
     *
576
     * @return boolean         true if directory is trusted
577
     * @throws SmartyException if PHP directory is not trusted
578
     */
579
    public function isTrustedPHPDir($filepath)
580
    {
581
        if (empty($this->trusted_dir)) {
582
            throw new SmartyException("directory '{$filepath}' not allowed by security setting (no trusted_dir specified)");
583
        }
584
        // check if index is outdated
585
        if (!$this->_trusted_dir || $this->_trusted_dir !== $this->trusted_dir) {
586
            $this->_php_resource_dir = array();
587
            $this->_trusted_dir = $this->trusted_dir;
588
            foreach ((array)$this->trusted_dir as $directory) {
589
                $directory = $this->smarty->_realpath($directory . '/', true);
590
                $this->_php_resource_dir[ $directory ] = true;
591
            }
592
        }
593
        $addPath = $this->_checkDir($filepath, $this->_php_resource_dir);
594
        if ($addPath !== false) {
595
            $this->_php_resource_dir = array_merge($this->_php_resource_dir, $addPath);
596
        }
597
        return true;
598
    }
599
 
600
    /**
601
     * Remove old directories and its sub folders, add new directories
602
     *
603
     * @param array $oldDir
604
     * @param array $newDir
605
     */
606
    private function _updateResourceDir($oldDir, $newDir)
607
    {
608
        foreach ($oldDir as $directory) {
609
            //           $directory = $this->smarty->_realpath($directory, true);
610
            $length = strlen($directory);
611
            foreach ($this->_resource_dir as $dir) {
612
                if (substr($dir, 0, $length) === $directory) {
613
                    unset($this->_resource_dir[ $dir ]);
614
                }
615
            }
616
        }
617
        foreach ($newDir as $directory) {
618
            //           $directory = $this->smarty->_realpath($directory, true);
619
            $this->_resource_dir[ $directory ] = true;
620
        }
621
    }
622
 
623
    /**
624
     * Check if file is inside a valid directory
625
     *
626
     * @param string $filepath
627
     * @param array  $dirs valid directories
628
     *
629
     * @return array|bool
630
     * @throws \SmartyException
631
     */
632
    private function _checkDir($filepath, $dirs)
633
    {
634
        $directory = dirname($this->smarty->_realpath($filepath, true)) . DIRECTORY_SEPARATOR;
635
        $_directory = array();
636
        if (!preg_match('#[\\\\/][.][.][\\\\/]#', $directory)) {
637
            while (true) {
638
                // test if the directory is trusted
639
                if (isset($dirs[ $directory ])) {
640
                    return $_directory;
641
                }
642
                // abort if we've reached root
643
                if (!preg_match('#[\\\\/][^\\\\/]+[\\\\/]$#', $directory)) {
644
                    // give up
645
                    break;
646
                }
647
                // remember the directory to add it to _resource_dir in case we're successful
648
                $_directory[ $directory ] = true;
649
                // bubble up one level
650
                $directory = preg_replace('#[\\\\/][^\\\\/]+[\\\\/]$#', DIRECTORY_SEPARATOR, $directory);
651
            }
652
        }
653
        // give up
654
        throw new SmartyException(sprintf('Smarty Security: not trusted file path \'%s\' ', $filepath));
655
    }
656
 
657
    /**
658
     * Loads security class and enables security
659
     *
660
     * @param \Smarty                $smarty
661
     * @param string|Smarty_Security $security_class if a string is used, it must be class-name
662
     *
663
     * @return \Smarty current Smarty instance for chaining
664
     * @throws \SmartyException when an invalid class name is provided
665
     */
666
    public static function enableSecurity(Smarty $smarty, $security_class)
667
    {
668
        if ($security_class instanceof Smarty_Security) {
669
            $smarty->security_policy = $security_class;
670
            return $smarty;
671
        } elseif (is_object($security_class)) {
672
            throw new SmartyException("Class '" . get_class($security_class) . "' must extend Smarty_Security.");
673
        }
674
        if ($security_class === null) {
675
            $security_class = $smarty->security_class;
676
        }
677
        if (!class_exists($security_class)) {
678
            throw new SmartyException("Security class '$security_class' is not defined");
679
        } elseif ($security_class !== 'Smarty_Security' && !is_subclass_of($security_class, 'Smarty_Security')) {
680
            throw new SmartyException("Class '$security_class' must extend Smarty_Security.");
681
        } else {
682
            $smarty->security_policy = new $security_class($smarty);
683
        }
684
        return $smarty;
685
    }
686
 
687
    /**
688
     * Start template processing
689
     *
690
     * @param $template
691
     *
692
     * @throws SmartyException
693
     */
694
    public function startTemplate($template)
695
    {
696
        if ($this->max_template_nesting > 0 && $this->_current_template_nesting++ >= $this->max_template_nesting) {
697
            throw new SmartyException("maximum template nesting level of '{$this->max_template_nesting}' exceeded when calling '{$template->template_resource}'");
698
        }
699
    }
700
 
701
    /**
702
     * Exit template processing
703
     */
704
    public function endTemplate()
705
    {
706
        if ($this->max_template_nesting > 0) {
707
            $this->_current_template_nesting--;
708
        }
709
    }
710
 
711
    /**
712
     * Register callback functions call at start/end of template rendering
713
     *
714
     * @param \Smarty_Internal_Template $template
715
     */
716
    public function registerCallBacks(Smarty_Internal_Template $template)
717
    {
718
        $template->startRenderCallbacks[] = array($this, 'startTemplate');
719
        $template->endRenderCallbacks[] = array($this, 'endTemplate');
720
    }
721
}