[freenet-dev] Not enough entropy

Post by Jano
Since the last version #1153, my node takes a very long time to start (half an
hour or more). Trying to load the homepage gives a page saying that "Freenet
Not enough entropy is available!
There isn't enough entropy available on your system... Freenet won't start
until it can gather enough.
This node runs in an unattended box, so any entropy sources will be non-human.
I have read somewhere that /dev/random is slow to refill and can be exhausted
easily if used too much. Could this be part of the problem?

This is the problem.

Launch a "find / >/dev/null" from a different shell and that should help
the OS to refill the entropy pool.

Jano

2008-07-18 13:59:38 UTC

Post by Jano
Since the last version #1153, my node takes a very long time to start (half
an hour or more). Trying to load the homepage gives a page saying that
Not enough entropy is available!
There isn't enough entropy available on your system... Freenet won't start
until it can gather enough.
This node runs in an unattended box, so any entropy sources will be
non-human. I have read somewhere that /dev/random is slow to refill and can
be exhausted easily if used too much. Could this be part of the problem?

This is the problem.
Launch a "find / >/dev/null" from a different shell and that should help
the OS to refill the entropy pool.

I'm going to try this, it's been two hours now with the node stuck waiting.

***

It worked. I know /dev/urandom is less secure, is there a likely possibility of
attacks if urandom is used instead?

Florent Daignière

2008-07-18 14:02:18 UTC

This is the problem.
Launch a "find / >/dev/null" from a different shell and that should help
the OS to refill the entropy pool.

I'm going to try this, it's been two hours now with the node stuck waiting.
***
It worked. I know /dev/urandom is less secure, is there a likely possibility of
attacks if urandom is used instead?

Before #1153 we were using urandom... and yes that was insecure.

I might introduce some code to generate hard-drive accesses in 1154.

Cory Nelson

2008-07-18 14:27:42 UTC

On Fri, Jul 18, 2008 at 7:02 AM, Florent Daignière

This is the problem.
Launch a "find / >/dev/null" from a different shell and that should help
the OS to refill the entropy pool.

I'm going to try this, it's been two hours now with the node stuck waiting.
***
It worked. I know /dev/urandom is less secure, is there a likely possibility of
attacks if urandom is used instead?

Before #1153 we were using urandom... and yes that was insecure.
I might introduce some code to generate hard-drive accesses in 1154.

You might want to check out HAVEGE: http://www.irisa.fr/caps/projects/hipsor/

It takes advantage of branch mispredictions to give high quality
randomness. The algorithm

Florent Daignière

2008-07-18 14:47:36 UTC

Post by Cory Nelson
On Fri, Jul 18, 2008 at 7:02 AM, Florent Daignière

This is the problem.
Launch a "find / >/dev/null" from a different shell and that should help
the OS to refill the entropy pool.

I'm going to try this, it's been two hours now with the node stuck waiting.
***
It worked. I know /dev/urandom is less secure, is there a likely possibility of
attacks if urandom is used instead?

Before #1153 we were using urandom... and yes that was insecure.
I might introduce some code to generate hard-drive accesses in 1154.

You might want to check out HAVEGE: http://www.irisa.fr/caps/projects/hipsor/
It takes advantage of branch mispredictions to give high quality
randomness. The algorithm is quite simple.

Are you aware that freenet is written in java? :) We can't rely on
architecture-specific problems to generate the entropy we need.

We are already using a cryptographically secure PRNG (Yarrow); The
node stalls because it can't gather the entropy needed to seed it.

NextGen$

Cory Nelson

2008-07-18 14:57:39 UTC

On Fri, Jul 18, 2008 at 7:47 AM, Florent Daignière

Post by Cory Nelson
On Fri, Jul 18, 2008 at 7:02 AM, Florent Daignière

This is the problem.
Launch a "find / >/dev/null" from a different shell and that should help
the OS to refill the entropy pool.

I'm going to try this, it's been two hours now with the node stuck waiting.
***
It worked. I know /dev/urandom is less secure, is there a likely possibility of
attacks if urandom is used instead?

Before #1153 we were using urandom... and yes that was insecure.
I might introduce some code to generate hard-drive accesses in 1154.

You might want to check out HAVEGE: http://www.irisa.fr/caps/projects/hipsor/
It takes advantage of branch mispredictions to give high quality
randomness. The algorithm is quite simple.

Are you aware that freenet is written in java? :) We can't rely on
architecture-specific problems to generate the entropy we need.
We are already using a cryptographically secure PRNG (Yarrow); The
node stalls because it can't gather the entropy needed to seed it.

If Java has some way to read the hardware timestamp, that's all that
is needed. Even if not - you guys already have some 3rd party native
library for bignum, right? HAVEGE is better than Yarrow or any PRNG
could hope to be - what's wrong with another lib if it means
randomness tha

Florent Daignière

2008-07-18 15:12:56 UTC

Post by Cory Nelson
On Fri, Jul 18, 2008 at 7:47 AM, Florent Daignière

Post by Cory Nelson
On Fri, Jul 18, 2008 at 7:02 AM, Florent Daignière