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PHP 保険付きメール
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リリース： 2016-06-13 12:07:55
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PHP 安全的电子邮件PHP E-mailPHP Error在上一节中的 PHP e-mail 脚本中，存在着一个漏洞。PHP E-mail 注入首先，请看上一节中的 PHP 代码：<html><body><?phpif (isset($_REQUEST['email']))//if "email" is filled out, send email  {  //send email  $email = $_REQUEST['email'] ;   $subject = $_REQUEST['subject'] ;  $message = $_REQUEST['message'] ;  mail("[email&#160;protected]", "Subject: $subject",  $message, "From: $email" );  echo "Thank you for using our mail form";  }else//if "email" is not filled out, display the form  {  echo "<form method='post' action='mailform.php'>  Email: <input name='email' type='text' /><br />  Subject: <input name='subject' type='text' /><br />  Message:<br />  <textarea name='message' rows='15' cols='40'>  </textarea><br />  <input type='submit' />  </form>";  }?></body></html>以上代码存在的问题是，未经授权的用户可通过输入表单在邮件头部插入数据。假如用户在表单中的输入框内加入这些文本，会出现什么情况呢？[email&#160;protected]%0ACc:[email&#160;protected]%0ABcc:[email&#160;protected],[email&#160;protected],[email&#160;protected],[email&#160;protected]%0ABTo:[email&#160;protected]与往常一样，mail() 函数把上面的文本放入邮件头部，那么现在头部有了额外的 Cc:, Bcc: 以及 To: 字段。当用户点击提交按钮时，这封 e-mail 会被发送到上面所有的地址！PHP 防止 E-mail 注入防止 e-mail 注入的最好方法是对输入进行验证。下面的代码与上一节类似，不过我们已经增加了检测表单中 email 字段的输入验证程序：<html><body><?phpfunction spamcheck($field)  {  //filter_var() sanitizes the e-mail   //address using FILTER_SANITIZE_EMAIL  $field=filter_var($field, FILTER_SANITIZE_EMAIL);    //filter_var() validates the e-mail  //address using FILTER_VALIDATE_EMAIL  if(filter_var($field, FILTER_VALIDATE_EMAIL))    {    return TRUE;    }  else    {    return FALSE;    }  }if (isset($_REQUEST['email']))  {//if "email" is filled out, proceed  //check if the email address is invalid  $mailcheck = spamcheck($_REQUEST['email']);  if ($mailcheck==FALSE)    {    echo "Invalid input";    }  else    {//send email    $email = $_REQUEST['email'] ;     $subject = $_REQUEST['subject'] ;    $message = $_REQUEST['message'] ;    mail("[email&#160;protected]", "Subject: $subject",    $message, "From: $email" );    echo "Thank you for using our mail form";    }  }else  {//if "email" is not filled out, display the form  echo "<form method='post' action='mailform.php'>  Email: <input name='email' type='text' /><br />  Subject: <input name='subject' type='text' /><br />  Message:<br />  <textarea name='message' rows='15' cols='40'>  </textarea><br />  <input type='submit' />  </form>";  }?></body></html>在上面的代码中，我们使用了 PHP 过滤器来对输入进行验证：FILTER_SANITIZE_EMAIL 从字符串中删除电子邮件的非法字符FILTER_VALIDATE_EMAIL 验证电子邮件地址
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