Re: Login Script: mysql_num_rows(): supplied argument is not a valid MySQL result resource

David Hutto schreef:

--- On Fri, 2/19/10, David Hutto <dwightdhutto@yahoo.com> wrote: From: David Hutto <dwightdhutto@yahoo.com> Subject: Login Script: mysql_num_rows(): supplied argument is not a valid MySQL result resource To: php-general@lists.php.net Date: Friday, February 19, 2010, 3:30 AM The following script is supposed to validate a username and password in a mysql db. When entering the username and password of a preregistered user, I get the following errors: Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in /var/www/login.php on line 24 Warning: Cannot modify header information - headers already sent by (output started at /var/www/login.php:24) in /var/www/login.php on line 26 On line 24 is:

if(!mysql_num_rows($login)) //if the username and pass are wrong

--The supplied argument is $login, which is previously defined as:

$login = mysql_query("SELECT * FROM 'userinfo' WHERE user = '$user' AND pass = '$pass`");

--which is further defined above it as these values: $user = $_POST['user']; //pulls the username from the form $pw = $_POST['pass']; //pulls the pass from the form $pass = md5($pw); //makes our password an md So why is the sum of those previous definitions an invalid argument for the mysql_query() to test for whether the username and md5 password values are true/equivalent to each other? Because basically !mysql_num_rows($login) is just if'ing the lack of a user/pass match, else it continues to set cookie and session variables. If I'm looking at this wrong let me know. Thanks for any help you may be able to provide, below is the full login.php page. David ******************************************************** This is the full login.php script, I'm pretty sure no other portions are needed to show at this point for the current problem: <?php $act = $_GET['act']; //retrives the page action if(empty($act)) //if there is no action { echo('<form action="login.php?act=auth" method="post" name="loginform" id="loginform"> <p>Username <input type="text" name="user"> </p> <p>Password <input type="password" name="pass"> </p> <p> <input type="submit" name="Submit" value="Login"> </p> </form>'); } elseif($act == "auth") //if our page action = auth { $user = $_POST['user']; //pulls the username from the form $pw = $_POST['pass']; //pulls the pass from the form $pass = md5($pw); //makes our password an md5 include("connect.php"); //connects to our mysql database $login = mysql_query("SELECT * FROM userinfo WHERE user = '$user' AND pass = '$pass`"); //selects info from our table if the row has the same user and pass that our form does if(!mysql_num_rows($login)) //if the username and pass are wrong {

        header("Location: login.php");  //redirects to our login page
        die(); //stops the page from going any further

} else {

        setcookie("user", $user, time()+3600);//sets our user cookie
                setcookie("pass", $pass, time()+3600);//sets our pass

cookie

                header("Location: memprar.php");//instead of yourpage.php it would be your protected page
  } }

?>

The query should be: SELECT * FROM userinfo WHERE user = '$user' AND pass = '$pass' Remember: ` for tables and columns, ' for strings. Also, look up SQL Injection, as your script contains a huge vulnerability. This can be fixed using mysql_real_escape_string, so it is this: ELECT * FROM userinfo WHERE user = '".mysql_real_escape_string($user)."' AND pass = '".mysql_real_escape_string($pass)."' -- Kind regards, Mark Cilissen / Pixlism