1: <?php
2: /**
3: * Smarty plugin
4: *
5: * @package Smarty
6: * @subpackage Security
7: * @author Uwe Tews
8: */
9:
10: /*
11: * FIXME: Smarty_Security API
12: * - getter and setter instead of public properties would allow cultivating an internal cache properly
13: * - current implementation of isTrustedResourceDir() assumes that Smarty::$template_dir and Smarty::$config_dir are immutable
14: * the cache is killed every time either of the variables change. That means that two distinct 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: * This is the list of template directories that are considered secure.
39: * $template_dir is in this list implicitly.
40: *
41: * @var array
42: */
43: public $secure_dir = array();
44: /**
45: * This is an array of directories where trusted php scripts reside.
46: * {@link $security} is disabled during their inclusion/execution.
47: *
48: * @var array
49: */
50: public $trusted_dir = array();
51: /**
52: * List of regular expressions (PCRE) that include trusted URIs
53: *
54: * @var array
55: */
56: public $trusted_uri = array();
57: /**
58: * This is an array of trusted static classes.
59: * If empty access to all static classes is allowed.
60: * If set to 'none' none is allowed.
61: *
62: * @var array
63: */
64: public $static_classes = array();
65: /**
66: * This is an array of trusted PHP functions.
67: * If empty all functions are allowed.
68: * To disable all PHP functions set $php_functions = null.
69: *
70: * @var array
71: */
72: public $php_functions = array(
73: 'isset', 'empty',
74: 'count', 'sizeof',
75: 'in_array', 'is_array',
76: 'time',
77: 'nl2br',
78: );
79: /**
80: * This is an array of trusted PHP modifiers.
81: * If empty all modifiers are allowed.
82: * To disable all modifier set $php_modifiers = null.
83: *
84: * @var array
85: */
86: public $php_modifiers = array(
87: 'escape',
88: 'count'
89: );
90: /**
91: * This is an array of allowed tags.
92: * If empty no restriction by allowed_tags.
93: *
94: * @var array
95: */
96: public $allowed_tags = array();
97: /**
98: * This is an array of disabled tags.
99: * If empty no restriction by disabled_tags.
100: *
101: * @var array
102: */
103: public $disabled_tags = array();
104: /**
105: * This is an array of allowed modifier plugins.
106: * If empty no restriction by allowed_modifiers.
107: *
108: * @var array
109: */
110: public $allowed_modifiers = array();
111: /**
112: * This is an array of disabled modifier plugins.
113: * If empty no restriction by disabled_modifiers.
114: *
115: * @var array
116: */
117: public $disabled_modifiers = array();
118: /**
119: * This is an array of trusted streams.
120: * If empty all streams are allowed.
121: * To disable all streams set $streams = null.
122: *
123: * @var array
124: */
125: public $streams = array('file');
126: /**
127: * + flag if constants can be accessed from template
128: *
129: * @var boolean
130: */
131: public $allow_constants = true;
132: /**
133: * + flag if super globals can be accessed from template
134: *
135: * @var boolean
136: */
137: public $allow_super_globals = true;
138:
139: /**
140: * Cache for $resource_dir lookup
141: *
142: * @var array
143: */
144: protected $_resource_dir = null;
145: /**
146: * Cache for $template_dir lookup
147: *
148: * @var array
149: */
150: protected $_template_dir = null;
151: /**
152: * Cache for $config_dir lookup
153: *
154: * @var array
155: */
156: protected $_config_dir = null;
157: /**
158: * Cache for $secure_dir lookup
159: *
160: * @var array
161: */
162: protected $_secure_dir = null;
163: /**
164: * Cache for $php_resource_dir lookup
165: *
166: * @var array
167: */
168: protected $_php_resource_dir = null;
169: /**
170: * Cache for $trusted_dir lookup
171: *
172: * @var array
173: */
174: protected $_trusted_dir = null;
175:
176: /**
177: * @param Smarty $smarty
178: */
179: public function __construct($smarty)
180: {
181: $this->smarty = $smarty;
182: }
183:
184: /**
185: * Check if PHP function is trusted.
186: *
187: * @param string $function_name
188: * @param object $compiler compiler object
189: *
190: * @return boolean true if function is trusted
191: * @throws SmartyCompilerException if php function is not trusted
192: */
193: public function isTrustedPhpFunction($function_name, $compiler)
194: {
195: if (isset($this->php_functions) && (empty($this->php_functions) || in_array($function_name, $this->php_functions))) {
196: return true;
197: }
198:
199: $compiler->trigger_template_error("PHP function '{$function_name}' not allowed by security setting");
200:
201: return false; // should not, but who knows what happens to the compiler in the future?
202: }
203:
204: /**
205: * Check if static class is trusted.
206: *
207: * @param string $class_name
208: * @param object $compiler compiler object
209: *
210: * @return boolean true if class is trusted
211: * @throws SmartyCompilerException if static class is not trusted
212: */
213: public function isTrustedStaticClass($class_name, $compiler)
214: {
215: if (isset($this->static_classes) && (empty($this->static_classes) || in_array($class_name, $this->static_classes))) {
216: return true;
217: }
218:
219: $compiler->trigger_template_error("access to static class '{$class_name}' not allowed by security setting");
220:
221: return false; // should not, but who knows what happens to the compiler in the future?
222: }
223:
224: /**
225: * Check if PHP modifier is trusted.
226: *
227: * @param string $modifier_name
228: * @param object $compiler compiler object
229: *
230: * @return boolean true if modifier is trusted
231: * @throws SmartyCompilerException if modifier is not trusted
232: */
233: public function isTrustedPhpModifier($modifier_name, $compiler)
234: {
235: if (isset($this->php_modifiers) && (empty($this->php_modifiers) || in_array($modifier_name, $this->php_modifiers))) {
236: return true;
237: }
238:
239: $compiler->trigger_template_error("modifier '{$modifier_name}' not allowed by security setting");
240:
241: return false; // should not, but who knows what happens to the compiler in the future?
242: }
243:
244: /**
245: * Check if tag is trusted.
246: *
247: * @param string $tag_name
248: * @param object $compiler compiler object
249: *
250: * @return boolean true if tag is trusted
251: * @throws SmartyCompilerException if modifier is not trusted
252: */
253: public function isTrustedTag($tag_name, $compiler)
254: {
255: // check for internal always required tags
256: if (in_array($tag_name, array('assign', 'call', 'private_filter', 'private_block_plugin', 'private_function_plugin', 'private_object_block_function',
257: 'private_object_function', 'private_registered_function', 'private_registered_block', 'private_special_variable', 'private_print_expression', 'private_modifier'))
258: ) {
259: return true;
260: }
261: // check security settings
262: if (empty($this->allowed_tags)) {
263: if (empty($this->disabled_tags) || !in_array($tag_name, $this->disabled_tags)) {
264: return true;
265: } else {
266: $compiler->trigger_template_error("tag '{$tag_name}' disabled by security setting", $compiler->lex->taglineno);
267: }
268: } elseif (in_array($tag_name, $this->allowed_tags) && !in_array($tag_name, $this->disabled_tags)) {
269: return true;
270: } else {
271: $compiler->trigger_template_error("tag '{$tag_name}' not allowed by security setting", $compiler->lex->taglineno);
272: }
273:
274: return false; // should not, but who knows what happens to the compiler in the future?
275: }
276:
277: /**
278: * Check if modifier plugin is trusted.
279: *
280: * @param string $modifier_name
281: * @param object $compiler compiler object
282: *
283: * @return boolean true if tag is trusted
284: * @throws SmartyCompilerException if modifier is not trusted
285: */
286: public function isTrustedModifier($modifier_name, $compiler)
287: {
288: // check for internal always allowed modifier
289: if (in_array($modifier_name, array('default'))) {
290: return true;
291: }
292: // check security settings
293: if (empty($this->allowed_modifiers)) {
294: if (empty($this->disabled_modifiers) || !in_array($modifier_name, $this->disabled_modifiers)) {
295: return true;
296: } else {
297: $compiler->trigger_template_error("modifier '{$modifier_name}' disabled by security setting", $compiler->lex->taglineno);
298: }
299: } elseif (in_array($modifier_name, $this->allowed_modifiers) && !in_array($modifier_name, $this->disabled_modifiers)) {
300: return true;
301: } else {
302: $compiler->trigger_template_error("modifier '{$modifier_name}' not allowed by security setting", $compiler->lex->taglineno);
303: }
304:
305: return false; // should not, but who knows what happens to the compiler in the future?
306: }
307:
308: /**
309: * Check if stream is trusted.
310: *
311: * @param string $stream_name
312: *
313: * @return boolean true if stream is trusted
314: * @throws SmartyException if stream is not trusted
315: */
316: public function isTrustedStream($stream_name)
317: {
318: if (isset($this->streams) && (empty($this->streams) || in_array($stream_name, $this->streams))) {
319: return true;
320: }
321:
322: throw new SmartyException("stream '{$stream_name}' not allowed by security setting");
323: }
324:
325: /**
326: * Check if directory of file resource is trusted.
327: *
328: * @param string $filepath
329: *
330: * @return boolean true if directory is trusted
331: * @throws SmartyException if directory is not trusted
332: */
333: public function isTrustedResourceDir($filepath)
334: {
335: $_template = false;
336: $_config = false;
337: $_secure = false;
338:
339: $_template_dir = $this->smarty->getTemplateDir();
340: $_config_dir = $this->smarty->getConfigDir();
341:
342: // check if index is outdated
343: if ((!$this->_template_dir || $this->_template_dir !== $_template_dir)
344: || (!$this->_config_dir || $this->_config_dir !== $_config_dir)
345: || (!empty($this->secure_dir) && (!$this->_secure_dir || $this->_secure_dir !== $this->secure_dir))
346: ) {
347: $this->_resource_dir = array();
348: $_template = true;
349: $_config = true;
350: $_secure = !empty($this->secure_dir);
351: }
352:
353: // rebuild template dir index
354: if ($_template) {
355: $this->_template_dir = $_template_dir;
356: foreach ($_template_dir as $directory) {
357: $directory = realpath($directory);
358: $this->_resource_dir[$directory] = true;
359: }
360: }
361:
362: // rebuild config dir index
363: if ($_config) {
364: $this->_config_dir = $_config_dir;
365: foreach ($_config_dir as $directory) {
366: $directory = realpath($directory);
367: $this->_resource_dir[$directory] = true;
368: }
369: }
370:
371: // rebuild secure dir index
372: if ($_secure) {
373: $this->_secure_dir = $this->secure_dir;
374: foreach ((array) $this->secure_dir as $directory) {
375: $directory = realpath($directory);
376: $this->_resource_dir[$directory] = true;
377: }
378: }
379:
380: $_filepath = realpath($filepath);
381: $directory = dirname($_filepath);
382: $_directory = array();
383: while (true) {
384: // remember the directory to add it to _resource_dir in case we're successful
385: $_directory[$directory] = true;
386: // test if the directory is trusted
387: if (isset($this->_resource_dir[$directory])) {
388: // merge sub directories of current $directory into _resource_dir to speed up subsequent lookup
389: $this->_resource_dir = array_merge($this->_resource_dir, $_directory);
390:
391: return true;
392: }
393: // abort if we've reached root
394: if (($pos = strrpos($directory, DS)) === false || !isset($directory[1])) {
395: break;
396: }
397: // bubble up one level
398: $directory = substr($directory, 0, $pos);
399: }
400:
401: // give up
402: throw new SmartyException("directory '{$_filepath}' not allowed by security setting");
403: }
404:
405: /**
406: * Check if URI (e.g. {fetch} or {html_image}) is trusted
407: * To simplify things, isTrustedUri() resolves all input to "{$PROTOCOL}://{$HOSTNAME}".
408: * So "http://username:password@hello.world.example.org:8080/some-path?some=query-string"
409: * is reduced to "http://hello.world.example.org" prior to applying the patters from {@link $trusted_uri}.
410: *
411: * @param string $uri
412: *
413: * @return boolean true if URI is trusted
414: * @throws SmartyException if URI is not trusted
415: * @uses $trusted_uri for list of patterns to match against $uri
416: */
417: public function isTrustedUri($uri)
418: {
419: $_uri = parse_url($uri);
420: if (!empty($_uri['scheme']) && !empty($_uri['host'])) {
421: $_uri = $_uri['scheme'] . '://' . $_uri['host'];
422: foreach ($this->trusted_uri as $pattern) {
423: if (preg_match($pattern, $_uri)) {
424: return true;
425: }
426: }
427: }
428:
429: throw new SmartyException("URI '{$uri}' not allowed by security setting");
430: }
431:
432: /**
433: * Check if directory of file resource is trusted.
434: *
435: * @param string $filepath
436: *
437: * @return boolean true if directory is trusted
438: * @throws SmartyException if PHP directory is not trusted
439: */
440: public function isTrustedPHPDir($filepath)
441: {
442: if (empty($this->trusted_dir)) {
443: throw new SmartyException("directory '{$filepath}' not allowed by security setting (no trusted_dir specified)");
444: }
445:
446: // check if index is outdated
447: if (!$this->_trusted_dir || $this->_trusted_dir !== $this->trusted_dir) {
448: $this->_php_resource_dir = array();
449:
450: $this->_trusted_dir = $this->trusted_dir;
451: foreach ((array) $this->trusted_dir as $directory) {
452: $directory = realpath($directory);
453: $this->_php_resource_dir[$directory] = true;
454: }
455: }
456:
457: $_filepath = realpath($filepath);
458: $directory = dirname($_filepath);
459: $_directory = array();
460: while (true) {
461: // remember the directory to add it to _resource_dir in case we're successful
462: $_directory[] = $directory;
463: // test if the directory is trusted
464: if (isset($this->_php_resource_dir[$directory])) {
465: // merge sub directories of current $directory into _resource_dir to speed up subsequent lookup
466: $this->_php_resource_dir = array_merge($this->_php_resource_dir, $_directory);
467:
468: return true;
469: }
470: // abort if we've reached root
471: if (($pos = strrpos($directory, DS)) === false || !isset($directory[2])) {
472: break;
473: }
474: // bubble up one level
475: $directory = substr($directory, 0, $pos);
476: }
477:
478: throw new SmartyException("directory '{$_filepath}' not allowed by security setting");
479: }
480: }
481: