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From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: Sun, 18 Jun 2017 21:11:20 +0200
Message-ID: <CAHmME9oLau3HhirPE-B=z-BVv7fph7Ws=smzsa6_SZGxY__auA@mail.gmail.com>
Subject: Re: [kernel-hardening] Re: [PATCH v4 13/13] random: warn when kernel
 uses unseeded randomness
To: "Theodore Ts'o" <tytso@mit.edu>,
        =?UTF-8?Q?Stephan_M=C3=BCller?= <smueller@chronox.de>,
        kernel-hardening@lists.openwall.com,
        Michael Ellerman <mpe@ellerman.id.au>,
        "Jason A. Donenfeld" <Jason@zx2c4.com>,
        Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        David Miller <davem@davemloft.net>, Eric Biggers <ebiggers3@gmail.com>
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On Sun, Jun 18, 2017 at 5:46 PM, Theodore Ts'o <tytso@mit.edu> wrote:
> You are effectively proposing that there ought to be a middle range of
> security between prandom_32, get_random_u32/get_random_u64 and
> get_random_bytes().  I think that's going to lead to all sorts of
> complexity and bugs from people not understanding when they should use
> get_random_u32 vs get_random_bytes versus prandom_u32.  And then we'll
> end up needing to audit all of the callsites for get_random_u32() so
> they don't violate this new usage rule that you are proposing.

I agree with you wholeheartedly.

get_random_* provides the secure random numbers.
prandom_* provides the insecure random numbers.

Introducing some kind of middle ground will result in needless
complexity and inevitable bugs.