I accidentally allowed YouTube to access the data on a canvas. How do I disable a website from access a canvas?

1 Answer 1


By default, Tor Browser forgets about permissions when you close it. You can easily check it by revisiting Youtube (and see if it asks for permission again).

If permissions.memory_only preference is set to false (default is true), Tor Browser stores permissions in a file named permissions.sqlite in the profile directory.

If you have this file and it's modified recently, you can use a program like sqlitestudio to selectively remove existing permissions.

If you want to remove all existing permissions, removing permissions.sqlite file should also do.

  • Thanks that's a to the point answer. I set memory_only to false as I want to always deny canvas extraction (haven't ever noticed anything that breaks when you do), but it's not quite clear what the other implications of this are. Does it just mean that a trace on your hdd might exist of which websites you have visited, or are there other consequences?
    – user517
    Jan 25, 2015 at 13:32
  • Plus, the permissions can be probed/inferred by the websites, hence can be used for linking different sessions of the same user.
    – gacar
    Feb 6, 2015 at 17:47

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .