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Date:   Fri, 14 Feb 2020 17:47:44 -0500
From:   "Theodore Y. Ts'o" <tytso@mit.edu>
To:     Rob Herring <robh@kernel.org>
Cc:     Masami Hiramatsu <mhiramat@kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Android Kernel Team <kernel-team@android.com>,
        Mark Salyzyn <salyzyn@android.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Richard Henderson <richard.henderson@linaro.org>,
        Mark Brown <broonie@kernel.org>,
        Kees Cook <keescook@chromium.org>,
        Hsin-Yi Wang <hsinyi@chromium.org>,
        Vasily Gorbik <gor@linux.ibm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Mike Rapoport <rppt@linux.ibm.com>,
        Arvind Sankar <nivedita@alum.mit.edu>,
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        Juergen Gross <jgross@suse.com>,
        Linux Doc Mailing List <linux-doc@vger.kernel.org>
Subject: Re: [PATCH 2/3] random: rng-seed source is utf-8
Message-ID: <20200214224744.GC439135@mit.edu>
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On Fri, Feb 14, 2020 at 01:58:35PM -0600, Rob Herring wrote:
> On Fri, Feb 14, 2020 at 12:10 AM Masami Hiramatsu <mhiramat@kernel.org> wrote:
> >
> > From: Mark Salyzyn <salyzyn@android.com>
> >
> > commit 428826f5358c922dc378830a1717b682c0823160
> > ("fdt: add support for rng-seed") makes the assumption that the data
> > in rng-seed is binary, when it is typically constructed of utf-8
> 
> Typically? Why is that?
> 
> > characters which has a bitness of roughly 6 to give appropriate
> > credit due for the entropy.

This is why I really think what gets specified via the boot command
line, or bootconfig, should specify the bits of entropy and the
entropy seed *separately*, so it can be specified explicitly, instead
of assuming that *everyone knows* that rng-seed is either (a) a binary
string, or (b) utf-8, or (c) a hex string.  The fact is, everyone does
*not* know, or everyone will have a different implementation, which
everyone will say is *obviously* the only way to go....

	      	     		     	  - Ted