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Date:      Fri, 11 Oct 2002 08:08:37 +0100
From:      Mark Murray <mark@grondar.za>
To:        "Firsto Lasto" <firstolasto@hotmail.com>
Cc:        mark@grondar.za, freebsd-hackers@FreeBSD.ORG
Subject:   Re: PRNG not seeded - error in non-root ssh inside 4.6.2 jails... 
Message-ID:  <200210110708.g9B78b01061654@grimreaper.grondar.org>
In-Reply-To: <F26Z4yeRPazsgOBUN8e0000f235@hotmail.com> ; from "Firsto Lasto" <firstolasto@hotmail.com>  "Thu, 10 Oct 2002 14:47:24 PDT."
References:  <F26Z4yeRPazsgOBUN8e0000f235@hotmail.com> 

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> 
> Do you mean recompile SSL using urandom instead of random ?

Yes.

> Would it be the exact same effect if I simply changed my /dev/random to 
> major/minor 2,4 instead of 2,3 ?

Yes. That would work.

> It seems like that would be much easier...

Indeed!

M

> > > Ok, I am not sure how I can do that though - I cannot successfully run
> > > `rndcontrol -s X` inside a jail.
> > >
> > > On the other hand, I already have:
> > >
> > > rand_irqs="9 10 11 13 14"
> > >
> > > In my rc.conf on the underlying host machine, and have done several 
> >boots
> > > with that in place.  So presumably I should be seeded just fine, but if 
> >I am
> > > not, I cannot change that in the jail because it seems I cannot set that 
> >(I
> > > assume it is a sysctl issue).
> > >
> > > Willing to try whatever you can think of next :)
> >
> >Hokay. Can you grovel around inside OpenSSL (src/crypto/openssl/...) and
> >find where the random device is read? If it is /dev/random, then change
> >that to /dev/urandom.
> >
> >See how that works.
> >
> >M
> >
> > > > > I can't seed it by banging on the keyboard - it is a headless server 
> >in
> > > >a
> > > > > rack thousands of miles from me :)
> > > > >
> > > > > Perhaps there is another way to do it ?
> > > >
> > > >Yes.
> > > >
> > > >You need to find sources of entropy in interrupts. Look at a
> > > >dmesg, and note which IRQ's your network device(s) and mass
> > > >storage controller(s) (both SCSI and ATA). Use any other
> > > >irq's that aren't too busy and may be somewhat random.
> > > >Staring at a 'systat 2 -vmstat' screen (right hand side)
> > > >may give some clues.
> > > >
> > > >Then use rndcontrol(8) to set up the seeding. There is a knob
> > > >in rc.conf to make this setting survive the next reboot.
> > > >
> > > >M
> > > >
> > > > > >Date: Thu, 03 Oct 2002 21:54:30 +0100
> > > > > >
> > > > > > > Sorry, here is the rest:
> > > > > > >
> > > > > > > Here is the output of the `dd` command using urandom:
> > > > > > >
> > > > > > > dd if=/dev/urandom of=/dev/stdout bs=512 count=1 | hexdump -C
> > > > > > > 1+0 records in
> > > > > > > 1+0 records out
> > > > > > > 00000000  a0 69 1a 7c 8f 32 e5 21  ae 7a 33 14 68 0b 8e a6
> > > > > > > |.i.|.2.!.z3.h...|
> > > > > >
> > > > > >... etc. Looking good.
> > > > > >
> > > > > > > $ ls -l /dev/*rand*
> > > > > > > crw-r--r--  1 root  wheel    2,   3 Sep  3 21:46 /dev/random
> > > > > > > crw-r--r--  1 root  wheel    2,   4 Sep  3 21:46 /dev/urandom
> > > > > >
> > > > > >Also good.
> > > > > >
> > > > > > > > > So then, as root I ran: `chmod 0666 /dev/stdout` and then I 
> >ran
> > > >your
> > > > > > > >`dd`
> > > > > > > > > command and got:
> > > > > > > > >
> > > > > > > > > $ dd if=/dev/random of=/dev/stdout bs=512 count=1 | hexdump 
> >-C
> > > > > > > > > 0+0 records in
> > > > > > > > > 0+0 records out
> > > > > > > > > 0 bytes transferred in 0.000036 secs (0 bytes/sec)
> > > > > >
> > > > > >Can you try a few of these while furiously abusing your keyboard?
> > > > > >I'm trying to see if /dev/random can be persuaded to give _any_
> > > > > >aoutput at all.
> > > > > >
> > > > > >Maybe do it on a vty instead of in X.
> > > > > >
> > > > > >M
> > > > > >--
> > > > > >o       Mark Murray
> > > > > >\_
> > > > > >O.\_    Warning: this .sig is umop ap!sdn
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > _________________________________________________________________
> > > > > Chat with friends online, try MSN Messenger: 
> >http://messenger.msn.com
> > > > >
> > > >--
> > > >o       Mark Murray
> > > >\_
> > > >O.\_    Warning: this .sig is umop ap!sdn
> > >
> > >
> > >
> > >
> > > _________________________________________________________________
> > > Send and receive Hotmail on your mobile device: http://mobile.msn.com
> > >
> > >
> > > To Unsubscribe: send mail to majordomo@FreeBSD.org
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> >--
> >o       Mark Murray
> >\_
> >O.\_    Warning: this .sig is umop ap!sdn
> 
> 
> 
> 
> _________________________________________________________________
> Send and receive Hotmail on your mobile device: http://mobile.msn.com
> 
-- 
o       Mark Murray
\_
O.\_    Warning: this .sig is umop ap!sdn

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