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