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Re: [kernel-hardening] [PATCH] random: warn when kernel uses unseeded randomness

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"Jason A. Donenfeld" <Jason@zx2c4.com> writes:

> This enables an important dmesg notification about when drivers have
> used the crng without it being seeded first. Prior, these errors would
> occur silently, and so there hasn't been a great way of diagnosing these
> types of bugs for obscure setups. By adding this as a config option, we
> can leave it on by default, so that we learn where these issues happen,
> in the field, will still allowing some people to turn it off, if they
> really know what they're doing and do not want the log entries.
>
> However, we don't leave it _completely_ by default. An earlier version
> of this patch simply had `default y`. I'd really love that, but it turns
> out, this problem with unseeded randomness being used is really quite
> present and is going to take a long time to fix. Thus, as a compromise
> between log-messages-for-all and nobody-knows, this is `default y`,
> except it is also `depends on DEBUG_KERNEL`. This will ensure that the
> curious see the messages while others don't have to.

All the distro kernels I'm aware of have DEBUG_KERNEL=y.

Where all includes at least RHEL, SLES, Fedora, Ubuntu & Debian.

So it's still essentially default y.

Emitting *one* warning by default would be reasonable. That gives users
who are interested something to chase, they can then turn on the option
to get the full story.

Filling the dmesg buffer with repeated warnings is really not helpful.

cheers

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Thread

Re: [PATCH] random: silence compiler warnings and fix race Theodore Ts'o <tytso@mit.edu> - 2017-06-20 08:10 +0200
  Re: [kernel-hardening] Re: [PATCH] random: silence compiler warnings  and fix race Joel Stanley <joel@jms.id.au> - 2017-06-20 08:30 +0200
  Re: [kernel-hardening] Re: [PATCH] random: silence compiler warnings and fix race Michael Ellerman <mpe@ellerman.id.au> - 2017-06-20 09:10 +0200
  Re: [PATCH] random: silence compiler warnings and fix race "Jason A. Donenfeld" <Jason@zx2c4.com> - 2017-06-20 10:20 +0200
    Re: [PATCH] random: silence compiler warnings and fix race Jeffrey Walton <noloader@gmail.com> - 2017-06-20 10:40 +0200
      Re: [PATCH] random: silence compiler warnings and fix race "Jason A. Donenfeld" <Jason@zx2c4.com> - 2017-06-20 11:00 +0200
        Re: [PATCH] random: silence compiler warnings and fix race Jeffrey Walton <noloader@gmail.com> - 2017-06-20 11:50 +0200
          Re: [kernel-hardening] Re: [PATCH] random: silence compiler warnings  and fix race Sandy Harris <sandyinchina@gmail.com> - 2017-06-20 20:00 +0200
            Re: [kernel-hardening] Re: [PATCH] random: silence compiler warnings  and fix race Kees Cook <keescook@chromium.org> - 2017-06-20 20:20 +0200
              Re: [kernel-hardening] Re: [PATCH] random: silence compiler warnings  and fix race "Jason A. Donenfeld" <Jason@zx2c4.com> - 2017-06-20 22:10 +0200
        Re: [PATCH] random: silence compiler warnings and fix race "Jason A. Donenfeld" <Jason@zx2c4.com> - 2017-06-20 11:50 +0200
          Re: [PATCH] random: silence compiler warnings and fix race Theodore Ts'o <tytso@mit.edu> - 2017-06-21 01:40 +0200
            Re: [PATCH] random: silence compiler warnings and fix race "Jason A. Donenfeld" <Jason@zx2c4.com> - 2017-06-21 02:00 +0200
              [PATCH] random: warn when kernel uses unseeded randomness "Jason A. Donenfeld" <Jason@zx2c4.com> - 2017-06-21 02:10 +0200
                Re: [PATCH] random: warn when kernel uses unseeded randomness Kees Cook <keescook@chromium.org> - 2017-06-21 02:20 +0200
                Re: [kernel-hardening] [PATCH] random: warn when kernel uses unseeded randomness Michael Ellerman <mpe@ellerman.id.au> - 2017-06-21 08:10 +0200
                Re: [kernel-hardening] [PATCH] random: warn when kernel uses  unseeded randomness Theodore Ts'o <tytso@mit.edu> - 2017-06-21 22:40 +0200
                Re: [kernel-hardening] [PATCH] random: warn when kernel uses unseeded randomness "Jason A. Donenfeld" <Jason@zx2c4.com> - 2017-06-22 02:10 +0200
            Re: [PATCH] random: silence compiler warnings and fix race Jeffrey Walton <noloader@gmail.com> - 2017-06-22 02:00 +0200
        Re: [PATCH] random: silence compiler warnings and fix race Theodore Ts'o <tytso@mit.edu> - 2017-06-20 12:00 +0200

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