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 X-Spam-Level: X-Spam-Status: No, score=-3.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7B608C3A5A6 for ; Thu, 29 Aug 2019 16:22:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 46CD420673 for ; Thu, 29 Aug 2019 16:22:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="MJf9BBcy" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727921AbfH2QWe (ORCPT ); Thu, 29 Aug 2019 12:22:34 -0400 Received: from mail-pl1-f194.google.com ([209.85.214.194]:39685 "EHLO mail-pl1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726784AbfH2QWb (ORCPT ); Thu, 29 Aug 2019 12:22:31 -0400 Received: by mail-pl1-f194.google.com with SMTP id az1so830734plb.6 for ; Thu, 29 Aug 2019 09:22:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=DdYdr6DVDvibDIbEnZ+Q/sFh6e07cbxVBi1D1KZkmHE=; b=MJf9BBcyqCSmz7DipJUqJz/xmbD2RMq8TlbsXLYyknI2/0T4sCih77zexM22p6fsD3 VOPAg2s0nfw8HvC8gmJEGh9S9voz26Mj3HsS7XxBCflzRa13tqP18CtWMY6VEaoBkog3 mNx/zUBmuYAX2/7CbnUK9IipcaT+gshqRGuX8= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=DdYdr6DVDvibDIbEnZ+Q/sFh6e07cbxVBi1D1KZkmHE=; b=GZ3cZXgRgfhk5a8Ts+UJiz2RxeyDHrVgLEC6/TQvPjUeo2HE3rGqwBdKzN93jQ4xod tnZbV+WAufQFMFxy9qfJLa0yrtsdOUrVWrI5F2SC6IXBr0wE+taK0GGDYsedGSkHtqNO O6tZYHrODQjN1TiinLCEQiIUTloDLS6dT8HxBFHPXsm0Pw19pOIeW5fHp6rIjUxoKbCW 0uI4V9IT9kZwPCxcoI/zMQ7TDZbqxQ7wfi89SjFUUccd7wX9fOAoIZKu5QGrZ29qACsR h7HhR7khk9gSS7JWr/DuL5FaSf4vQYy7m/lzoWi2FJAG2Maw6cHw6y948FK07W4uSXvj 8vcw== X-Gm-Message-State: APjAAAV4L4PzTV2mxiy+bv+wKhBXM7NsW0A71z8xOyrPmlV6zi1dTkzf jz6CsmA6bttbMu3Y4LUupebllw== X-Google-Smtp-Source: APXvYqyYQQq2IoRQtC1ZL2R4vak6Z1iGu18iUN+0L1VB1/kKRn+IH73nQqod3Fcbj/NJatoGlKaF2g== X-Received: by 2002:a17:902:a607:: with SMTP id u7mr10863720plq.43.1567095750695; Thu, 29 Aug 2019 09:22:30 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id t189sm4180836pfd.58.2019.08.29.09.22.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 29 Aug 2019 09:22:29 -0700 (PDT) Date: Thu, 29 Aug 2019 09:22:28 -0700 From: Kees Cook To: Hsin-Yi Wang Cc: Stephen Boyd , "Theodore Y . Ts'o" , "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" , Russell King , Catalin Marinas , Will Deacon , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H . Peter Anvin" , "Paul E . McKenney" , Kate Stewart , "David S . Miller" , Viresh Kumar , Marek Szyprowski , Arnd Bergmann , Marc Zyngier , Julien Thierry , Greg Kroah-Hartman , Wei Li , Anders Roxell , Rob Herring , Aaro Koskinen , Daniel Thompson , Tim Chen , Rik van Riel , Waiman Long , Marcelo Tosatti , Peter Zijlstra , Armijn Hemel , Grzegorz Halat , Len Brown , Shaokun Zhang , Mike Rapoport , Guenter Roeck , Andrew Morton , Mathieu Desnoyers , Alexey Dobriyan , Yury Norov , Josh Poimboeuf , Jiri Kosina , Mukesh Ojha , lkml Subject: Re: [PATCH v9 2/3] fdt: add support for rng-seed Message-ID: <201908290921.1F0FCC9E5@keescook> References: <20190822071522.143986-1-hsinyi@chromium.org> <20190822071522.143986-3-hsinyi@chromium.org> <5d5ed368.1c69fb81.419fc.0803@mx.google.com> <201908241203.92CC0BE8@keescook> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 29, 2019 at 06:03:57PM +0800, Hsin-Yi Wang wrote: > On Thu, Aug 29, 2019 at 1:36 AM Kees Cook wrote: > > > > Can this please be a boot param (with the default controlled by the > > CONFIG)? See how CONFIG_RANDOM_TRUST_CPU is wired up... > > > > -Kees > > > > Currently rng-seed read and added in setup_arch() --> > setup_machine_fdt().. -> early_init_dt_scan_chosen(), which is earlier > than parse_early_param() that initializes early_param. > > If we want to set it as a boot param, add_bootloader_randomness() can > only be called after parse_early_param(). The seed can't be directly > added to pool after it's read in. We need to store into global > variable and load it later. > If this seems okay then I'll add a patch for this. Thanks This seems like a good idea to me. > > --- a/drivers/of/fdt.c > +++ b/drivers/of/fdt.c > @@ -1096,13 +1096,15 @@ static const char *config_cmdline = CONFIG_CMDLINE; > > +const void* rng_seed; > +int rng_seed_len; These should be __initdata, yes? > + > int __init early_init_dt_scan_chosen(unsigned long node, const char *uname, > int depth, > void *data) > { > int l = 0; > const char *p = NULL; > char *cmdline = data; > - const void *rng_seed; > > pr_debug("search \"chosen\", depth: %d, uname: %s\n", depth, uname); > > @@ -1137,10 +1139,8 @@ int __init early_init_dt_scan_chosen(unsigned > long node, const char *uname, > > pr_debug("Command line is: %s\n", (char*)data); > > - rng_seed = of_get_flat_dt_prop(node, "rng-seed", &l); > - if (rng_seed && l > 0) { > - add_bootloader_randomness(rng_seed, l); // > Originally it's added to entropy pool here > - > + rng_seed = of_get_flat_dt_prop(node, "rng-seed", &rng_seed_len); > + if (rng_seed && rng_seed_len > 0) { > /* try to clear seed so it won't be found. */ > > diff --git a/include/linux/random.h b/include/linux/random.h > index 831a002a1882..946840bba7c1 100644 > --- a/include/linux/random.h > +++ b/include/linux/random.h > @@ -31,6 +31,15 @@ static inline void add_latent_entropy(void) > static inline void add_latent_entropy(void) {} > #endif > > +extern const void* rng_seed; > +extern int rng_seed_len; > + > +static inline void add_bootloader_entropy(void) > +{ > + if (rng_seed && rng_seed_len > 0) > + add_bootloader_randomness(rng_seed, rng_seed_len); > +} And this should be __init > + > extern void add_input_randomness(unsigned int type, unsigned int code, > unsigned int value) __latent_entropy; > extern void add_interrupt_randomness(int irq, int irq_flags) __latent_entropy; > diff --git a/init/main.c b/init/main.c > index 71847af32e4e..f74a8c7b34af 100644 > --- a/init/main.c > +++ b/init/main.c > @@ -645,6 +645,7 @@ asmlinkage __visible void __init start_kernel(void) > * - adding command line entropy > */ > rand_initialize(); > + add_bootloader_entropy(); > add_latent_entropy(); > add_device_randomness(command_line, strlen(command_line)); > boot_init_stack_canary(); But yeah, looks reasonable to me. -- Kees Cook