?? ??? ??

?? ?? ??? ??? ???? ??? ?????? ???? ?? ??? ????. ??? ??? ?? ?? ???? ??? ????? ?? ??? multipart/form-data? ???? ???:

CODE:

<form action="upload.php" method="POST"
enctype="multipart/form-data">

?? ??? ???? ??? ?? ??? ??? ??? ????, ??? ??? ???? ????? ?? ??? ?? ??? ?? ??? ? ????.

???? ??? ???? ???? ? ?? ?? ??? ?? ?????.

CODE:

<input type="file" name="attachment" />

? ??? ????? ?? ??? ????. ????? ??????? ?? ??? ??? ???? ??? ???? ?? ???? ?? ??? ?? ????? ????? ?? ??? ? ????. Safari ?????? ???? ??? ????. ???? ??? ??? ??? ?????.

?? ??? ????? ? ? ???? ?? ??? ???? ?? ??? ???? ? ?? ????.

CODE:

<form action="upload.php" method="POST"
enctype="multipart/form-data">
  
Please choose a file to upload:
  
  

  
  

??? ?? ?? MAX_FILE_SIZE? ????? ???? ?? ??? ??? ?????. ?? ??. ?? ????? ? ?? ??? ????? ? ?? ??? ???? ?? ??? ? ??? ???? ?????? ??? ?????. ? ??? ???? ???? ???? ??? ? ????.

PHP ?? ?? ? upload_max_filesize? ???? ? ?? ?? ?? ??? ?????. ??? ??? ?? ???? ?? ?????? post_max_size(POST ??? ?? ?? ??? ??)? ????? ??? ? ????.

?? ???? upload.php? ?? ?? ?? $_FILES:

CODE:

<?php
 
  header(&#39;Content-Type: text/plain&#39;);
  print_r($_FILES);
 
  ?>

??? ????? ???? ?? ???.txt?? ??? ?????. ??? ??? ??? ????.

CODE:

  Chris Shiflett
  http://miracleart.cn/

? ??? upload.php ????? ????? ?????? ??? ??? ??? ? ? ????.

CODE:

 Array
  (
      [attachment] => Array
          (
              [name] => author.txt
              [type] => text/plain
              [tmp_name] => /tmp/phpShfltt
              [error] => 0
              [size] => 36
          )
 
  )

??? ?? PHP? ???? ?? ???(super global) $_FILES ??? ???? ????? ?? ???? ?? ??? ??? ?? ????. ????? ??? ??? ??? ?? ?? ??? ???? ?? ?? ?? ????? ?? HTTP ?? ??? ???? ?? ????.

CODE:

POST /upload.php HTTP/1.1
  Host: example.org
  Content-Type: multipart/form-data;
boundary=----------12345
  Content-Length: 245
 
  ----------12345
  Content-Disposition: form-data; name="attachment";
filename="author.txt"
  Content-Type: text/plain
 
  Chris Shiflett
  http://miracleart.cn/
 
  ----------12345
  Content-Disposition: form-data;
name="MAX_FILE_SIZE"
 
  1024
  ----------12345--

?? ??? ??? ??? ???, ?? ? ?? ?????? ??? ? ??? ???. ???? ??? ??? ????? tmp_name, ?? ? ??? ?? PHP?? ?????.

PHP? ???? ??? ?? ???? ?? ?? ??(? ???? /tmp/phpShfltt)? ???? ??? ???? ??? ?? ???? ???? ?? ?? ?? ??? ???? ????. tmp_name? ???? ???? ??(/etc/passwd? ?? ??? ??)?? ???? ??? ???? ??? ????. ???? tmp_name ?? ??? ? ?? ??? ?? ??? ?? ??? ???? ????? ???. ??? ?? ??? ??? ?? ??? ?? ??? ?? ??? ?? ?? ????. ?? ??? ??? ???? ??? ??? ?? ??? ???? ??? ? ????.

PHP? ??? ??? ??? ???? ?? is_uploaded_file( ) ? ? ?? ??? ??? ?????. move_uploaded_file( ). tmp_name? ??? ???? ???? ???? ?? ?? is_uploaded_file()? ??? ? ????:

CODE:

????

如果你希望只把上傳的文件移到一個(gè)固定位置，你可以使用move_uploaded_file( )：

CODE:

 <?php
 
  $old_filename =
$_FILES[&#39;attachment&#39;][&#39;tmp_name&#39;];
  $new_filename = &#39;/path/to/attachment.txt&#39;;
 
  if (move_uploaded_file($old_filename,
$new_filename))
  {
    /* $old_filename is an uploaded file, and the
move was successful. */
  }
 
  ?>

最后你可以用 filesize( ) 來校驗(yàn)文件的大?。?/span>

CODE:

 <?php
 
  $filename = $_FILES[&#39;attachment&#39;][&#39;tmp_name&#39;];
 
  if (is_uploaded_file($filename))
  {
    $size = filesize($filename);
  }
 
  ?>

這些安全措施的目的是加上一層額外的安全保護(hù)層。最佳的方法是永遠(yuǎn)盡可能少地去信任。?

以上就是PHP安全-文件上傳攻擊的內(nèi)容，更多相關(guān)內(nèi)容請關(guān)注PHP中文網(wǎng)（miracleart.cn）！