Mysql PDO PHP更改数据库名称不会引发任何错误，但会杀死我的页面

Question

i have a problem with my database and error checking.

If a hacker decided to change the name of my database or any of the tables it will kill my page.

I found this out after trying my webpage on another computer where i had the favorites folder named favourites.

I have tried everything from try catch error handling to checking for a count and then throwing to an error page if 0 count returned. Iv tried allsortsto no avail.

i would normally send my user to a error page. But i cannot re-directg with a header location because the checking is in the middle of a PDO and while loop

il show you the code.

How can i avoid this problem

If the favorites database name is changed to anything other than favorites. it kills the page... But half of the page gets displayed. But i cannot redirect with header location if i try to catch the error.. Which is not even registering as an error..

if ($_SESSION['loggedin']==='001'){


if ($db = new PDO("mysql:host=localhost;dbname=favourrites", '????', '')){
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

   //add ;pagination order by limit
   $query11="SELECT * FROM `$useremail` WHERE `faveID` = '$listID' ";

   $stat11=$db->prepare($query11);
    $stat11->execute();

        while($row = $stat11->fetch()){
        $faveID=$row['faveID'];
        }


          if(!isset($faveID)) {$faveID="000";}
          else                                              
          if(empty($faveID)) {$faveID="000";}
          else
          if(!$faveID) {$faveID="000";}


     if ($faveID===$listID){
     echo"
         <img id='favicon[$fid]' data-variable-uid='{$UID}' data-variable- 
          listid='{$listID}' data-variable-accountname='{$accountname}' 
          src='../images/mainpage/fave1.png' title='Allready Added To 
          Favorites' class='iconlarge' style='opacity:0.9' 
          onclick='favecheck($fid);'></img>";            
    }
    else
        {               
         echo" 
         <img id='favicon[$fid]' data-variable-uid='{$UID}' data-variable- 
         listid='{$listID}' data-variable-accountname='{$accountname}' 
         src='../images/mainpage/fave2.png' title='Add To Your Favorites 
         List' class='iconlarge' style='opacity:1' 
         onclick='favecheck($fid);'></img>"; 
        }

}else{

error_reporting(E_ALL); 
ini_set("display_errors", 1);
header("Location: ../imageupload/error");
die();


echo '<script type="text/javascript">';
echo 'window.location.href="../imageupload/error.php";';
echo '</script>';
echo '<noscript>';
echo '<meta http-equiv="refresh" content="0;url='.$url.'" />';
echo '</noscript>'; 
exit();

}

}       

The above code has added attempts to re-direct but none have worked so far.including many others

like checking for a count result ect...

How do i redirect to my error page.

I tried a function call, but im not familiar with PHP functions and i attempted to call it like a jscript function.

Any help is greatly needed.

Thank you.

Answer 1

if a hacker has access to change the db name, its kind of all over.

but you can do this

try {
    $db = $db = new PDO("mysql:host=localhost;dbname=favourrites", '????', '')
} catch (PDOException $e) {
    //echo 'Connection failed: ' . $e->getMessage(); // i suggest you do something with the error
    header("Location: ../imageupload/error");
    die();
}

in the catch do the redirect. But again you really should be in a position where this could ever happen.

Answer 2

Have 2 database users, 1 is a "super-user" that is used by yourself when you're directly accessing the database.

The second user is the "applications user" which your app/page uses to access it's own database, this one is "locked down" so that it just has permission to do just what it needs to it's own tables. Anything that it should not be able to do, it's set so that it doesn't have permission to do that action/access a table.

You should ALWAYS use prepared statements for ALL queries so that you don't accidentally open up any security holes (SQL Injection attacks) if you were to change the source of any data to that provided by a user. ( NEVER trust any data submitted by any user, no matter how well you know them.

If the database is unavailable for any reason depending on your app you might want to consider exiting the script, echoing a user-friendly error message to the user (but not giving away any technical details, log the details of the error to your error logs)