Re: [Tails-dev] [doc] wiping flash media

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Autor: sajolida
Data:  
Para: The Tails public development discussion list
Assunto: Re: [Tails-dev] [doc] wiping flash media
intrigeri:
> hi,
>
> https://tails.boum.org/forum/Wiping_Flash_Media:_Problem_in_TAILS_Doc/
> reveals two serious problems in a section of our documentation: first,
> it's unclear and may easily lead to confusion; second, it's wrong: the
> paper we refer to clearly states that "Free space overwriting left
> most of the data on the drive".


I read the thread and I agree that the doc says something quite
different from the paper. That's a mistake.

The current doc basically says that in order to securely delete a file
from a USB you could delete the file and then the run "Wipe available
diskspace" even if you have other files on the volume. Which is wrong
according to the paper and the comments on the thread.

I don't want to keep the lingo "overwriting the entire visible address
space" and we anyway need to provide a method to actually do so.

Suggesting to delete all files first and then wipe all the disk space
would probably be wrong as well since then the space taken up by the
file system structure won't be wiped twice.

We could propose to wipe the entire device and then reformat it.
But srm doesn't seem to run on block devices: I get "Warning: /dev/sdc
is not a regular file, rename/unlink only!". On the other hand shred
seems to work as usual. It is included in Tails but doesn't have a
graphical interface.

If my thinking is right I don't think we can document a GUI procedure to
really wipe a USB stick at the moment. The solution could be either:

- to integrate shred in nautilus-wipe, and propose "Wipe the entire
device" for block devices or
- to make srm work on block devices.