Civi/Core/Security/PharExtensionInterceptor.php

   1 <?php
   2
   3 namespace Civi\Core\Security;
   4
   5 use TYPO3\PharStreamWrapper\Assertable;
   6 use TYPO3\PharStreamWrapper\Helper;
   7 use TYPO3\PharStreamWrapper\Exception;
   8
   9 /**
  10  * An alternate PharExtensionInterceptor to support phar-based CLI tools.
  11  *
  12  * This is largely based on Drupal\Core\Security\PharExtensionInterceptor,
  13  * originally licensed under GPL2+
  14  *
  15  * @see \TYPO3\PharStreamWrapper\Interceptor\PharExtensionInterceptor
  16  */
  17 class PharExtensionInterceptor implements Assertable {
  18
  19   /**
  20    * Determines whether phar file is allowed to execute.
  21    *
  22    * The phar file is allowed to execute if:
  23    * - the base file name has a ".phar" suffix.
  24    * - it is the CLI tool that has invoked the interceptor.
  25    *
  26    * @param string $path
  27    *   The path of the phar file to check.
  28    * @param string $command
  29    *   The command being carried out.
  30    *
  31    * @return bool
  32    *   TRUE if the phar file is allowed to execute.
  33    *
  34    * @throws Exception
  35    *   Thrown when the file is not allowed to execute.
  36    */
  37   public function assert(string $path, string $command): bool {
  38     if ($this->baseFileContainsPharExtension($path)) {
  39       return TRUE;
  40     }
  41     throw new Exception(
  42       sprintf(
  43         'Unexpected file extension in "%s"',
  44         $path
  45       ),
  46       1535198703
  47     );
  48   }
  49
  50   /**
  51    * Determines if a path has a .phar extension or invoked execution.
  52    *
  53    * @param string $path
  54    *   The path of the phar file to check.
  55    *
  56    * @return bool
  57    *   TRUE if the file has a .phar extension or if the execution has been
  58    *   invoked by the phar file.
  59    */
  60   private function baseFileContainsPharExtension($path) {
  61     $baseFile = Helper::determineBaseFile($path);
  62     if ($baseFile === NULL) {
  63       return FALSE;
  64     }
  65     // If the stream wrapper is registered by invoking a phar file that does
  66     // not not have .phar extension then this should be allowed. For
  67     // example, some CLI tools recommend removing the extension.
  68     $backtrace = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS);
  69     // Find the last entry in the backtrace containing a 'file' key as
  70     // sometimes the last caller is executed outside the scope of a file. For
  71     // example, this occurs with shutdown functions.
  72     do {
  73       $caller = array_pop($backtrace);
  74     } while (empty($caller['file']) && !empty($backtrace));
  75     if (isset($caller['file']) && $baseFile === Helper::determineBaseFile($caller['file'])) {
  76       return TRUE;
  77     }
  78     $fileExtension = pathinfo($baseFile, PATHINFO_EXTENSION);
  79     return strtolower($fileExtension) === 'phar';
  80   }
  81
  82 }