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From: "Theodore Y. Ts'o" <tytso@mit.edu>
To: Mark Salyzyn <salyzyn@android.com>
Cc: Rob Herring <robh@kernel.org>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Android Kernel Team <kernel-team@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>,
	Dominik Brodowski <linux@dominikbrodowski.net>,
	Thomas Gleixner <tglx@linutronix.de>,
	Alexander Potapenko <glider@google.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Pawan Gupta <pawan.kumar.gupta@linux.intel.com>,
	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
Date: Tue, 18 Feb 2020 12:14:53 -0500	[thread overview]
Message-ID: <20200218171453.GE147128@mit.edu> (raw)
In-Reply-To: <243ab5a8-2ce1-1465-0175-3f5d483cbde1@android.com>

On Tue, Feb 18, 2020 at 08:01:51AM -0800, Mark Salyzyn wrote:
> I am additionally concerned about add_bootloader_randomness() because it is
> possible for it to sleep because of add_hwgenerator_randomness() as once it
> hits the entropy threshold. As-is it can not be used inside start_kernel()
> because the sleep would result in a kernel panic, and I suspect its use
> inside early_init_dt_scan_chosen() for the commit "fdt: add support for
> rng-seed" might also be problematic since it is effectively called
> underneath start_kernel() is it not?
> 
> If add_bootloader_randomness was rewritten to call add_device_randomness()
> always, and when trusted also called the functionality of the new
> credit_trusted_entropy_bits (no longer needing to be exported if so), then
> the function could be used in both start_kernel() and
> early_init_dt_scan_chosen().

That's a good point, and it's a bug in add_bootloader_randomness().
That should be easily fixed by simply having it call mix_pool_bytes()
and credit_entropy_bits() directly.  I'll create a patch...

    			  	     	  	   - Ted

  parent reply	other threads:[~2020-02-18 17:17 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-14  6:10 [PATCH 0/3] random: add random.rng_seed to bootconfig entry Masami Hiramatsu
2020-02-14  6:10 ` [PATCH 1/3] bootconfig: Support non-ascii characters in value Masami Hiramatsu
2020-02-14  6:10 ` [PATCH 2/3] random: rng-seed source is utf-8 Masami Hiramatsu
2020-02-14 18:14   ` Hsin-Yi Wang
2020-02-14 19:58   ` Rob Herring
2020-02-14 22:47     ` Theodore Y. Ts'o
2020-02-14 22:55       ` Mark Salyzyn
2020-02-15  0:53         ` Theodore Y. Ts'o
2020-02-18 16:01           ` Mark Salyzyn
2020-02-18 16:52             ` Hsin-Yi Wang
2020-02-18 17:14             ` Theodore Y. Ts'o [this message]
2020-02-14  6:10 ` [PATCH 3/3] random: add random.rng_seed= bootconfig option Masami Hiramatsu
2020-02-14 13:49 ` [PATCH 0/3] random: add random.rng_seed to bootconfig entry Rob Herring
2020-02-14 17:00   ` Mark Salyzyn
2020-02-14 18:14     ` Rob Herring
2020-02-14 18:31       ` Mark Salyzyn
2020-02-15  0:17       ` Masami Hiramatsu

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