@@ -3,7 +3,9 @@ Also tracked by ticket: [[!tails_ticket 10181]]
What's the problem
------------------
some ideas/suggestions:
We want the Tails community to be diverse. In order to achieve this, our documentation should be the most welcoming possible, to all spectra of gender and provide the same openness in all translations. Also see [Debian's diversity statement](https://www.debian.org/intro/diversity).
In this case the situation is pretty much the same than with the DVD one. No
seed, and adding one is very difficult if not impossible (except with the
seed. And adding one is very difficult if not impossible (except with the
Windows installation where we may ask upstream to implement that in the
Universal USB Installer, but well...).
That's also not really the way we encourge users to use Tails, so as with DVD
That's also not really the way we encourage users to use Tails, so as with DVD
there's maybe no point to fix the situation here, and the same workaround could
be applied (document it).
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@@ -92,10 +102,11 @@ That's supposed to be the standard way to use Tails.
Note that in this case, there are two situations: booting this installation
with persistence enabled, and without.
It is worth noting too that the first time this Tails installation is booted,
most of the time the first step is to configure persistence, which means
creating an encrypted partition. At this step though, there is at the moment
probably very little entropy, so this may weaken the LUKS volume encryption.
It is worth noting that the first time this Tails installation is
booted, most of the time the first step is to configure persistence,
which means creating an encrypted partition. At this step though, there
is probably very little entropy at this moment, which may weaken the
LUKS volume encryption.
### Virtual Machines
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@@ -120,6 +131,9 @@ partition is created.
### Use the Tails installer to create a better seed [[!tails_ticket 11897]]
Note that we'll likely soon distribute a USB image and won't use Tails
installer anymore for creating Tails devices. [[!tails_ticket 15292]]
Tails installer can be used on Debian and Ubuntu, and is the tool people
running OSX or Windows are told to use to install their final Tails
USB stick with, by using an intermediary Tails to create the final USB.
...
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@@ -128,32 +142,34 @@ Tails installer could store a seed in the FAT filesystem of the system
partition. That would workaround this first boot problem not handled by the
persistence option.
We can't sadly update this seed while running Tails, as mounting RW the system
We sadly can't update this seed while running Tails, as read-write mounting the system
FAT partition during a Tails session does not work. So the question whether updating it
or not is open.
If we want to do so, we'll have to update it at the system shutdown. This will
mean remount this partition, write the new random seed, then unmount it and
start the shutdown of the system. Obviously we can do this only in normal
shutdown process, and will have to avoid it in emergency shutdown mode.
shutdown process, and we'll have to avoid it in emergency shutdown mode.
We may alternatively not update it, and use it only when the persistence is not
enabled. That would still be a unique source of entropy per Tails installation,
so that would be a better situation that the current one.
so that would be a better situation than the current one.
One drawback: this would break the ability to verify this system partition with
a simple shasum operation.
### Use stronger/more entropy collectors [[!tails_ticket 5650]]
As already stated, Tails run Haveged, and rngd (since 2.6 for the later).
As already stated, Tails runs Haveged, and rngd (since 2.6 for the later).
We may want to add other sources though, given there are concerns about Haveged,
and rngd starts only when a hardware RNG is detected, which is not so often the
case.
XXX: It would be nice to have a study (read: a survey of packages, etc) of all the
useful entropy gathering daemons that might be of use on a Tails system. (and have this tested on computers with/without intel rng or things like an entropykey)
XXX: It would be nice to have a study (read: a survey of packages, etc)
of all the useful entropy gathering daemons that might be of use on a
Tails system. (and have this tested on computers with/without intel rng
* randomsound: probably a bad idea in the Tails context as we're discussing a
Greeter option to deactivate the microphone.
### Block booting till enough entropy has been gathered
### Block booting until enough entropy has been gathered
One way to ensure Tails is booting with enough entropy would be to block during
the boot if the system is lacking of it.
One way to ensure Tails is booting with enough entropy would be to block
the boot while the system is lacking it.
But this brings questions about how to interact correctly with the users,
as blocking without notifications would be terrible UX. Also Tails boot time is
a bit long already, and this may grow it quite a bit more again.
XXX: So before going on, we need a bit more data about the state of the entropy when
Tails boot, specially now that we have several entropy collector daemons. It may
very well be that this case do not happen anymore. And if it is, we need to know
on average how much time that blocking would last. [Sycamoreone] [[!tails_ticket
Tails boots, especially now that we have several entropy collector daemons. It may
very well be that this case does not happen anymore. And if it does, we need to know
on average how much time that blocking would last. [[!tails_ticket
11758]]
### Regulary check available entropy and notify if low
An idea that has been mentioned several time is to have a service that
check if the available entropy is high enough, and notify the user if
it's not the case. One downside, is that observing the entropy pool costs
An idea that has been mentioned several times is to have a service that
checks if the available entropy is high enough, and notifies the user if
it's not the case. One downside is, that observing the entropy pool costs
randomness, so this may have to be implemented with care or is worth
discussing/researching the costs/benefits.
## Also see
* [Schleuder thread about haveged](https://0xacab.org/schleuder/schleuder/issues/194)
* The
[federal office for IT security in Germany analysed the rng in linux kernel 4.9 and all changes made up to 4.17](https://www.bsi.bund.de/SharedDocs/Downloads/EN/BSI/Publications/Studies/LinuxRNG/LinuxRNG_EN.pdf?__blob=publicationFile&v=10).
* [checking for available entropy](https://salsa.debian.org/tookmund-guest/pgpcr/issues/16)
## Related tickets
This is about [[!tails_ticket 7642]], [[!tails_ticket 7675]],
[[!tails_ticket 6116]], [[!tails_ticket 11897]] and friends.
