[Cryptography] /dev/random has issues

[Stephan Mueller]

Hi Ted,

> On Thu, Oct 17, 2013 at 09:12:48AM -0700, John Denker wrote:
> > Here is an experiment you can do, if you have a Linux system:
> >   cat /proc/sys/kernel/random/entropy_avail
> > 
> > I predict that it is likely to be a smallish number, less than 192
> > bits, not enough to cut a PGP key.  This seems to conflict with
> > the stated purpose of having /dev/random, and with the purpose
> > of having buffers within the device.
> 
> This is a known problem, and I have a patch pending for the next merge
> window to address this.
> 
> http://git.kernel.org/cgit/linux/kernel/git/tytso/random.git/commit/?h
> =dev&id=f5c2742c23886e707f062881c5f206c1fc704782

There is one more strain on the entropy: ASLR. I provided a patch once 
(http://lkml.org/lkml/2012/12/11/167) that would have covered some 
aspects, but that was shot down with a link to a different patch -- see 
that thread.

Unfortunately, there is no fix for this issue as of now. Andrew 
mentioned an easy patch, which I think is not appropriate -- but Ted and 
Andrew think it is good.a

Ted, maybe it may be helpful to push either Andrew's or my the patch 
again, because that issue is a real strain.


Ciao
Stephan