Member Avatar for Venom Rush

Hi there

I'm having a bit of a problem. As the title suggests, I'm creating $_SESSION's such as

$_SESSION[''.$row[0].'']

dynamically which is working perfectly, but the problem is I don't know how to call that same variable on a template page that I click through to.

At the moment I have the following:

$query = "SELECT eid, title, content, image, image2 FROM diary WHERE eid = '".$_SESSION[''.$row[0].'']."'";

Clearly this isn't working because the session variable could be any of the id's pulled from the database on the previous page and therefore the template page shows no content. I need some way of tying the variable from the previous page to the variable on the template page without using symantic URL encoding.

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All 29 Replies

Member Avatar for nav33n

Why dont you assign the value to a variable and then use that variable ?
Eg.

<?php  //page1.php
session_start();
$_SESSION['eid']="1234";
// rest of your code... 
?>
<?php //page2.php
session_start();
$eid=$_SESSION['eid'];
$query = "SELECT eid, title, content, image, image2 FROM diary WHERE eid ='$eid'";
// rest of your code
?>
Member Avatar for Venom Rush

Why dont you assign the value to a variable and then use that variable ?
Eg.

<?php  //page1.php
session_start();
$_SESSION['eid']="1234";
// rest of your code... 
?>
<?php //page2.php
session_start();
$eid=$_SESSION['eid'];
$query = "SELECT eid, title, content, image, image2 FROM diary WHERE eid ='$eid'";
// rest of your code
?>

Beacuse my code goes like this:

<?php  //page1.php
session_start();
// some code
//create query
$query = "SELECT eid, title, SUBSTRING(content, 1, 200), thumb_image FROM diary ORDER BY eid DESC";
// some more code
while($row = mysql_fetch_row($result))
	{
	if (!$_SESSION[$row[0]]) {
		$_SESSION[$row[0]] = $row[0];
	} 				
	//echo output here
	}
// rest of your code... 
?>

This is intended so that if I click on the link to the template page only the info relating to a particular eid will be displayed

Member Avatar for nav33n

How are you differentiating between different links ? Say you have 4 links ? Arent you passing some id for different links ?

Member Avatar for nav33n

And how will you know which $_SESSION[$row[0]] value has to be passed ?

Member Avatar for Venom Rush

And how will you know which $_SESSION[$row[0]] value has to be passed ?

Thats exactly what I'm trying to figure out. Is there no way of doing this without having the info attached to the URL?

Member Avatar for nav33n

I dont think so. hmmm.. There is a weird way of doing it (which I wouldn't prefer). I hope you are looping to print the urls. What you can do is, use onclick event, set $_SESSION[$row[0]] value to a hidden variable and submit the form. :S

<html>
<body>
<?php
//connection
//select db
$query="select eid from table";
$result=mysql_query($query);
while($row=mysql_fetch_array($result)){
echo "<form method=\"post\">";
echo "<input type=\"hidden\" name=\"eid\">";

echo "<a href=\"#\" onclick=\"javascript: document.form.eid.value='$_SESSION[$row[0]]'; document.form.action=\"template.php\"; document.form.submit();\">";
}
?>

As I said, this is the 'worst' way of doing it :P . But if you dont want to attach the info to the url, then you can do it this way ! I haven't tested the code(maybe the code wont even work!). Just giving you an idea on how it might work.
Cheers,
Naveen

Member Avatar for Venom Rush

Hmmm, not ideal as you've said. Is there any real chance that a semantic URL attack could happen if I put the eid in the URL? Or am I relatively safe?

Member Avatar for nav33n

You can have an array of all the eids and put it in a session. Then, everytime a user clicks on a link, check whether the eid is in the array of eids. If its present, then display respective page. Else, send the user to "you know where" ! Also, use mysql_real_escape_string or addslashes.

Member Avatar for Venom Rush

You can have an array of all the eids and put it in a session. Then, everytime a user clicks on a link, check whether the eid is in the array of eids. If its present, then display respective page. Else, send the user to "you know where" ! Also, use mysql_real_escape_string or addslashes.

So what I'd need to do is dynamically create a form around each row of info that is displayed, linking it to template.php, and then have code on template.php that searches for the row with the relevant eid and displays it?

Member Avatar for nav33n

No. you dont need a form if you are passing the eid in the url. While displaying the links, just concat eid at the end of the links and in template.php, check if that eid is in the session array of eids. If eid is in the array, fetch relevant details for that eid from the table and display it !

Member Avatar for Venom Rush

No. you dont need a form if you are passing the eid in the url. While displaying the links, just concat eid at the end of the links and in template.php, check if that eid is in the session array of eids. If eid is in the array, fetch relevant details for that eid from the table and display it !

I'm not quite following you. I'm feeling really blonde today :P Could you be so kind as to give a rough example of what you mean.

Member Avatar for nav33n

Okay !

<?php //page1.php
//connection
//select db
session_start();
$valid_eid=array();
$query="select eid,description from table";
$result=mysql_query($query);
while($row=mysql_fetch_array($result)){
	$eid=$row['eid'];
	$description=$row['description'];
	$valid_eid[]=$eid;
	echo "<a href=\"template.php?eid=$eid\">".$description."</a>"; //will display all the links
}
$_SESSION['eid_array']=$valid_eid;
?>
<?php //template.php
session_start();
//connection
//select db
$eid=mysql_real_escape_string($_REQUEST['eid']);
$valid_eid=$_SESSION['eid_array'];
if(in_array($eid,$valid_eid)){
	$query="select * from table where eid='$eid'";
	//fetch details and print
} else {
	echo "Eid is not valid !";
	exit; //or redirect the user to an error page. 
}
?>

Hope that helps !

Member Avatar for Venom Rush

Okay !

<?php //page1.php
//connection
//select db
session_start();
$valid_eid=array();
$query="select eid,description from table";
$result=mysql_query($query);
while($row=mysql_fetch_array($result)){
	$eid=$row['eid'];
	$description=$row['description'];
	$valid_eid[]=$eid;
	echo "<a href=\"template.php?eid=$eid\">".$description."</a>"; //will display all the links
}
$_SESSION['eid_array']=$valid_eid;
?>
<?php //template.php
session_start();
//connection
//select db
$eid=mysql_real_escape_string($_REQUEST['eid']);
$valid_eid=$_SESSION['eid_array'];
if(in_array($eid,$valid_eid)){
	$query="select * from table where eid='$eid'";
	//fetch details and print
} else {
	echo "Eid is not valid !";
	exit; //or redirect the user to an error page. 
}
?>

Hope that helps !

I see the eid is part of the URL. Would it display like that? If it does then I already have a way of doing that simply using $_GET.

page1's link:

<a href=www.example.com/template.php?eid=$eid />

page2 code:

//create query
$query = "SELECT eid, title, content, image, image2 FROM diary WHERE eid = '".$_GET['eid']."'";
Member Avatar for nav33n

Yep. You can do it that way. But the user can change eid to whatever value he wants ! My code will check if the eid is valid or not.

Member Avatar for Venom Rush

Yep. You can do it that way. But the user can change eid to whatever value he wants ! My code will check if the eid is valid or not.

Ok, so even if someone adds a valid eid into the URL it will give an error?

Member Avatar for nav33n

It wont. Because, it will check if the eid is valid. I am adding all the valid eids to an array remember :P. It will display the error message if eid is not in the array. So, this way, the user can't alter with eids !

Member Avatar for Venom Rush

It wont. Because, it will check if the eid is valid. I am adding all the valid eids to an array remember :P. It will display the error message if eid is not in the array. So, this way, the user can't alter with eids !

Thought as much :P Well thanks for all your help nav33n. Keep well.

Member Avatar for nav33n

You are welcome !

Member Avatar for Venom Rush

Hi nav33n

I have one more question. If there is no check to see if the eid is valid does it pose any sort of security risk?

Member Avatar for nav33n

It depends on the loopholes in your script. It wont be a threat if you handle it in a right way.

Member Avatar for Venom Rush

Ok, so as long as I filter any data passed I should be fine?

Member Avatar for nav33n

Yep. Exactly.

Member Avatar for Venom Rush

Yep. Exactly.

Thanks nav33n.

P.S. Grats on "Veteran Poster" ;)

Member Avatar for nav33n

thanks! lol..that makes me feel lil 'old'. :P

Member Avatar for Venom Rush

thanks! lol..that makes me feel lil 'old'. :P

LOL...I'll send you a zimmerframe ;)

Member Avatar for nav33n

;)

Member Avatar for DangerDev

Hmmm, not ideal as you've said. Is there any real chance that a semantic URL attack could happen if I put the eid in the URL? Or am I relatively safe?

its not good to put info into url which u dont want others to know.

Member Avatar for Venom Rush

its not good to put info into url which u dont want others to know.

Ok, well eid isn't sensitive data so I'm not worried

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