Re: [PATCH] openssl: Enable os option for with-rand-seed as well

[Adrian Bunk <bunk@stusta.de>]

On Fri, Sep 20, 2019 at 01:38:29PM +0000, Mikko.Rapeli@bmw.de wrote:
> On Fri, Sep 20, 2019 at 03:13:44PM +0200, Andrey Zhizhikin wrote:
> > Hello Raj,
> > 
> > On Tue, Sep 17, 2019 at 8:50 PM Khem Raj <raj.khem@gmail.com> wrote:
> > >
> > > with openSSL 1.1.1d we start seeing errors like
> > >
> > > Error Generating Key
> > > 139979727451584:error:2406C06E:random number generator:RAND_DRBG_instantiate:error retrieving entropy:../openssl-1.1.1d/crypto/rand/drbg_lib.c:342:
> > >
> > > when using openssl from openssl-native on build hosts, this is due to
> > > limiting the random seed to devrandom, to support older hosts, since the
> > > option allows to have a comma separated list of methods to try, we can
> > > try the default first and if that fails then fallback to devrandom, this
> > > will ensure that it keeps working with build systems which dont support
> > > getrandom()
> > >
> > > Signed-off-by: Khem Raj <raj.khem@gmail.com>
> > > Cc: Adrian Bunk <bunk@stusta.de>
> > > Cc: Alexander Kanavin <alex.kanavin@gmail.com>
> > > ---
> > 
> > Just as a test report for this patch:
> > 
> > I've tested this patch on the HW (i.MX8M Mini EVK) and unfortunately
> > my sshd given up with a message: PRNG is not seeded
> 
> > Reverting commits (effectively rolling back to openssl 1.1.1c) made
> > sshd operable again.:
> > 53b5654d6e openssl: Enable os option for with-rand-seed as well
> > 2c6b9b918c openssl: Upgrade 1.1.1c -> 1.1.1d
> 
> Do you have rng-tools on the image? That helped me with the kernel random pool
> initialization for sshd in iMX8 and openssl 1.1.1x.
> 
> I don't see how 53b5654d6e could change this behavior for target openssl.
> 2c6b9b918c could change the behavior and would be suprise.
>...

OpenSSL is full of surprises...

CHANGES says:
    Linux kernels 4.8 and later, don't have a reliable way to detect 
    that /dev/urandom has been properly seeded, so a failure is raised 
    for this case (i.e. the getentropy(2) call has already failed).

It seems to be correct to give an error here, and lack of rng-tools 
and/or kernel support for the iMX8 RNG is something that should be
fixed by the user.

OTOH, this kind of changes make it hard to justify upgrading openssl
in stable branches.

> -Mikko

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed