File Helper and Canonicalization issues

[eluser]dazed[/eluser]
Hi Guys,

Second issue so lets see if your responses are as quick as before

I have created a form that once all the details have been entered creates a txt file. This all works, the issue I have is that it asks for what the file name should be.

Again this works until you get a little evil :roll:

if you type into the form that you want the filename to be ../../filename.txt it does not save the file in the correct place and causes a whole load of other issues.

Now I have tried xss_clean and a number of other form validation rules to try and encode the dots and slashes but none of them seem to work.

Have any of you got any best practices or countermeasure's to this issue??

Thanks for your help,

Dazed