Re: tpm_tis TPM2.0 not detected on cold boot

From: Jarkko Sakkinen
Date: Thu Jan 03 2019 - 10:04:42 EST


On Thu, Jan 03, 2019 at 02:38:11PM +0100, Michael Niewöhner wrote:
> On Thu, 2019-01-03 at 15:27 +0200, Jarkko Sakkinen wrote:
> > On Sun, Dec 23, 2018 at 12:55:12PM +0100, Michael Niewöhner wrote:
> > > There is another issue but I don't know if both are related. Maybe that's
> > > just a
> > > timing issue...
> > >
> > > root@debian:~# dd if=/dev/hwrng bs=1 count=1
> > > dd: error reading '/dev/hwrng': Operation not permitted
> > > 0+0 records in
> > > 0+0 records out
> > > 0 bytes copied, 0.755958 s, 0.0 kB/s
> > > root@debian:~# dd if=/dev/hwrng bs=1 count=1 | xxd; dd if=/dev/hwrng bs=1
> > > count=1 | xxd
> > > dd: error reading '/dev/hwrng': Operation not permitted
> > > 0+0 records in
> > > 0+0 records out
> > > 0 bytes copied, 0.755697 s, 0.0 kB/s
> > > 1+0 records in
> > > 1+0 records out
> > > 00000000: 52 R
> > > 1 byte copied, 0.0106268 s, 0.1 kB/s
> > >
> > >
> > > Michael
> >
> > What does /sys/devices/virtual/misc/hw_random/rng_current show?
> >
> > Did run commands as a sanity check on my laptop and seem to work.
> >
> > /Jarkko
>
> rng_current says "tpm-rng-0", which should be correct

Is /dev/tpm0 accessible and usable?

/Jarkko