linux-kernel - Re: BPF RNG

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Message-ID: <CAGXu5j+Ny=1YF0BkATbU3Xb-fb=_0a1W-iZ3jYFhTcWrTPqCJQ@mail.gmail.com>
Date:   Tue, 16 Apr 2019 08:55:59 -0500
From:   Kees Cook <keescook@...gle.com>
To:     Daniel Borkmann <daniel@...earbox.net>
Cc:     Hannes Frederic Sowa <hannes@...essinduktion.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>,
        "Reshetova, Elena" <elena.reshetova@...el.com>,
        Alexei Starovoitov <ast@...nel.org>
Subject: Re: BPF RNG

[correcting Alexei's email address and resending...]

On Tue, Apr 16, 2019 at 8:54 AM Kees Cook <keescook@...gle.com> wrote:
>
> Hi,
>
> In looking at prandom_u32() users, I noticed that BPF uses its own
> state variable with bpf_user_rnd_u32(). It appears that this state is
> never reseeded like regular prandom_u32(). (See __prandom_timer().) Is
> this intentional, or should reseeding be happening?
>
> -Kees
>
> --
> Kees Cook



-- 
Kees Cook