From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 648EBC433FE for ; Mon, 7 Nov 2022 17:34:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232881AbiKGReU (ORCPT ); Mon, 7 Nov 2022 12:34:20 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46686 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231464AbiKGReQ (ORCPT ); Mon, 7 Nov 2022 12:34:16 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2F7FA21816; Mon, 7 Nov 2022 09:34:15 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id C0BA2611DA; Mon, 7 Nov 2022 17:34:14 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BEDD3C433D6; Mon, 7 Nov 2022 17:34:13 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="lVLa1BG4" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1667842451; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=B4SMF6oVs5RRpJDRVxFyeTr9TfajDc8wD+p7wUzg6d0=; b=lVLa1BG4y7erbzc5C/3bpbaTgEY+pR8MFJfu8uqrcp/NRDzcASGe/cOufRrtuwEurMJo/9 wxvX1aahpUD1jRmawKwQqQDjzXjC7CR3OwE1gbX5EA4zZpURAXV+gkQ9WlkG9pH385KqH+ nj3t74P+vn1W/y9IueAxh6yp9xs2cfI= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id a4e34559 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Mon, 7 Nov 2022 17:34:10 +0000 (UTC) Date: Mon, 7 Nov 2022 18:34:07 +0100 From: "Jason A. Donenfeld" To: Rob Herring Cc: devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Frank Rowand Subject: Re: [PATCH] of: fdt: parse early params before adding bootloader randomness Message-ID: References: <20221105014613.113503-1-Jason@zx2c4.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 07, 2022 at 11:28:20AM -0600, Rob Herring wrote: > On Fri, Nov 4, 2022 at 8:46 PM Jason A. Donenfeld wrote: > > > > FDT is examined so early that it's before the first incidental call to > > parse_early_param(). This is similar to EFI, except EFI actually added > > an explicitly call to parse_early_param(). Let's do the same here, so > > that specifying `random.trust_bootloader=0` is not ignored. > > > > Fixes: d97c68d178fb ("random: treat bootloader trust toggle the same way as cpu trust toggle") > > Cc: Rob Herring > > Cc: Frank Rowand > > Signed-off-by: Jason A. Donenfeld > > --- > > drivers/of/fdt.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c > > index 7b571a631639..6d959117fd4f 100644 > > --- a/drivers/of/fdt.c > > +++ b/drivers/of/fdt.c > > @@ -1195,6 +1195,9 @@ int __init early_init_dt_scan_chosen(char *cmdline) > > > > rng_seed = of_get_flat_dt_prop(node, "rng-seed", &l); > > if (rng_seed && l > 0) { > > + /* Parse random.trust_bootloader if it's in command line. */ > > + parse_early_param(); > > I don't think it's good that the timing of calling this is dependent > on "rng-seed" being present or not. So perhaps move it up to after the > cmdline is set. > > Either way, the other issue is the cmdline is not necessarily fixed at > this point with some architectures doing their own > append/prepend/override of the cmdline. We can't seem to get common > implementation there finished. I'm doubtful that corner case would > actually be hit though. Hm, yea. I'm actually now having second thoughts about this one too for other reasons: FDT isn't the only arch that has this issue. It's also a problem on x86 and m68k. Maybe the random.trust_bootloader toggle should just go away, since already your bootloader can do whatever it wants to the kernel it executes? Not sure; I'll think on it a bit I guess... Jason