Accidentally sent the following reply March 8 direct to Intrigeri
instead of the list. Correcting that now.
Intrigeri:
> Hi,
>
> sajolida (2020-02-25):
>> Surprisingly, it's not even clear to me what the implications of the
>> Language and Region settings can be on privacy. So I'm moving the
>> discussion to tails-dev@??? in order to ask our fellow developers.
>
> First, most, if not all, exploited applications have access to
> locale configuration.
>
> Wrt. network fingerprinting:
>
> - We have to assume that some applications may expose the system's
> locale configuration as part of their network activity.
>
> - For Tor Browser and Thunderbird, our configuration tries to avoid
> this (best effort) but it's impossible to prove we did not
> miss anything.
>
> Wrt. local storage:
>
> - If an adversary can read the content of the persistent storage, I'm
> pretty sure that the locale configuration can be easily inferred
> from that.
>
> - If/once we allow persisting the locale in cleartext on the system
> partition, this information will be available to an adversary
> who seizes the Tails device.
>
What I'm hearing is that changing locale is a significant
fingerprinting, therefore privacy, risk.
Maybe a message should be displayed when people make a change to the
locale settings in Greeter explaining the additional risk and asking
them to confirm before proceeding?