On Wed, Sep 26, 2018 at 6:35 PM Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx> wrote: > > On Wed, Sep 26, 2018 at 11:24:55AM +0800, Louis Collard wrote: > > Some systems, for example embedded systems, do not generate > > enough entropy on boot through interrupts, and boot may be blocked for > > several minutes waiting for a call to getrandom to complete. > > > > Currently, random data is read from a hwrng when it is registered, > > and is loaded into primary_crng. This data is treated in the same > > way as data that is device-specific but otherwise unchanging, and > > so primary_crng cannot become initialized with the data from the > > hwrng. > > > > This change causes the data initially read from the hwrng to be > > treated the same as subsequent data that is read from the hwrng if > > it's quality score is non-zero. > > > > The implications of this are: > > > > The data read from hwrng can cause primary_crng to become > > initialized, therefore avoiding problems of getrandom blocking > > on boot. > > > > Calls to getrandom (with GRND_RANDOM) may be using entropy > > exclusively (or in practise, almost exclusively) from the hwrng. > > > > Regarding the latter point; this behavior is the same as if a > > user specified a quality score of 1 (bit of entropy per 1024 bits) > > so hopefully this is not too scary a change to make. > > > > This change is the result of the discussion here: > > https://patchwork.kernel.org/patch/10453893/ > > > > Signed-off-by: Louis Collard <louiscollard@xxxxxxxxxxxx> > > Acked-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx> > > /Jarkko Thanks! Adding a few people I think I should have included previously - I'm new to this process so apologies for any missteps; please let me know if there is anything else I can / should be doing!
