[Buildroot] [PATCH] package/rng-tools: make jitterentropy conditional

Matthew Weber matthew.weber at rockwellcollins.com
Thu Feb 13 17:07:36 UTC 2020


Yegor,


On Tue, Feb 11, 2020 at 9:22 AM Yegor Yefremov
<yegorslists at googlemail.com> wrote:
>
> Hi Matt,
>
> On Tue, Feb 11, 2020 at 4:06 PM Matthew Weber
> <matthew.weber at rockwellcollins.com> wrote:
> >
> > Peter,
> >
> >
> > On Sat, Feb 8, 2020 at 1:13 PM Peter Korsgaard <peter at korsgaard.com> wrote:
> > >
> > > >>>>> "Matthew" == Matthew Weber <matthew.weber at rockwellcollins.com> writes:
> > >
> > >  > Thomas,
> > >  > On Wed, Feb 5, 2020 at 2:46 PM Matthew Weber
> > >  > <matthew.weber at rockwellcollins.com> wrote:
> > >  >>
> > >  >> Thomas,
> > >  >>
> > >  >> On Wed, Feb 5, 2020 at 1:33 PM Thomas Petazzoni
> > >  >> <thomas.petazzoni at bootlin.com> wrote:
> > >  >> >
> > >  >> > On Wed,  5 Feb 2020 12:26:08 -0600
> > >  >> > Matt Weber <matthew.weber at rockwellcollins.com> wrote:
> > >  >> >
> > >  >> > > The update of rng-tools from 5 to 6.7 introduced a change where
> > >  >> > > the jitterentropy library was enabled by default instead of
> > >  >> > > returning a special 66 return code to hangle the case of no
> > >  >> > > hwrng. This patch reverts that change and allows a user to
> > >  >> > > select when to enable the jitterentropy source. The bug
> > >  >> > > documents an issue of when a hwrng is enabled with jitterentropy
> > >  >> > > there is a longer boot time.
> > >  >> >
> > >  >> > I don't understand this story of the 66 return code. Could you explain
> > >  >> > a bit more ?
> > >  >>
> > >  >> In Buildroot commit 22cb51e1 the systemd support addition included the
> > >  >> successcode change based on the Fedora bugfix for ignoring if no hwrng
> > >  >> is present (https://bugzilla.redhat.com/show_bug.cgi?id=892178).
> > >
> > >  > Ryan Barnett noticed that rng-tools dropped the special return code.
> > >  > I guess we could just drop support for this special case as well....
> > >  > https://github.com/nhorman/rng-tools/blob/v6.8/rngd.c#L805
> > >
> > > Has that Fedora patch ever been included upstream? I don't seem to find
> > > it in the history.
> >
> > It doesn't look like it.  I'm wondering if we should just drop this
> > systemd unit return behavior and put a comment in the service file
> > about enabling an entropy package if this service fails without a
> > hardware rng present.  Seems too complicated to try and cover this
> > special case.
> >
> > >
> > > I btw see there is a 6.9 release with more bugfixes, care to send a
> > > patch bumping the version?
> >
> > I'll review the one that was just sent.  I also ping'd the original
> > bug report to see if they could test with this bump as there are a
> > number of minor jitterentropy related fixes.
> > http://patchwork.ozlabs.org/patch/1235396/
>
> We had similar issue today with am335x (kernel 5.4.x). Bumping
> rng-tools to v6.9 helped.
>

Thank you for that feedback, I'll make this patch is superseded as the
bump resolved the bug.  I'll add a note with this patchwork thread in
the bug report as well.

Matt


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