[winswitch] About clipboard-filter-file option

[Antoine Martin]

On 02/03/2020 08:19, 尾形 祐紀 via shifter-users wrote:
> Hello
> 
> It’s a pretty rudimentary question,
> I want to exclude png and jpeg format data from the contents of the clipboard. 
> Is it OK if the contents of the file specified in the --clipboard-filter-file option are as follows?
> 
> .*\.(png|jpeg)$
Probably not.
The filter applies to clipboard data not clipboard content type names.
And the PNG file header contains 'PNG' in uppercase, the JPEG header is
even harder to identify.
In any case, this is probably not the way to go about it: you would also
prevent copying of any plain text data containing those two strings.
Also, it would not stop the copying of image data in other formats. (ie:
webp)

A better solution would be to tell the clipboard code to ignore all
image content-types. You may be able to achieve this with:
XPRA_DISCARD_TARGET=^image/.* xpra start ...

Note that this would not completely prevent image data exfiltration,
only make it more difficult.

Cheers,
Antoine



> 
> Thanks in advance