Exactly like I said, just check this:
$id='/etc/passwd';
if($id && eregi('^[a-z0-9_]+\.html',$id)) include($id);
else die('Go away!');The regular expression prevents anyone from accessing any file that is not in your web root (http://your.server.net/) or its name does contain any other character then letters, numbers or underscore or does not end with html extension. This is pretty strict so a chance you will miss something is 0.
The syntex of the regular expression depend on your needs, I don't know them so I can't help you.
Mantas Kriauciunas wrote:
Hello Marek,
Thanks for the answer, but i think you misunderstood me because of my bad english. What i mean is the people with that code can access and view files on any place on my server and see the passwords stored in some files, decode them, and do stuff like that. I wanted to know how to prevent that from happening? If the people make file like this, how to protect myself so they could not view the /etc/passwd file?
Thursday, July 10, 2003, 5:13:33 AM, you wrote:
MK> Mantas Kriauciunas wrote:
The problem is if the make script <? if($id) include($id); ?> and then just write test.php?id=/etc/passwd , they see all the file.
MK> Check if $id is valid. Exact way depends on the structure of the files.
MK> Example 1: All included files are in web root and are named MK> something.html, something can contain letters, underscore, digits.
MK> if($id && eregi('^[a-z0-9_]+\.html',$id)) include($id);
MK> Example 2: The included files split into several directories, which can MK> contain letters, underscore, digits.
MK> if($id && eregi('^[a-z0-9_]+/[a-z0-9_]+\.html',$id)) include($id);
MK> Sure, this assumes you have nothing to hide in your *.html files.
So how to make sure that no one can access other people files and server files? and is there any way that nobody would be able to download php files or how to make them look like code when they are downloaded. Thanks!
P.S If someone knows good links please reply me! thanks a lot!
---Don't Get Mad, Ged Glad , Buy Gladware---
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