From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Mon, 04 May 2026 15:53:18 +0200 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by lore.white.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1wJtjb-000ugw-1z for lore@lore.pengutronix.de; Mon, 04 May 2026 15:53:18 +0200 Received: from bombadil.infradead.org ([2607:7c80:54:3::133]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1wJtja-0000My-4w for lore@pengutronix.de; Mon, 04 May 2026 15:53:18 +0200 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=kbqDWZeSf5dQXbsBP8UmgkCgH4bVGgfrwKAJzzQH8Ys=; b=Aib8NE2Spa/0Vaf1zC+9zwU5y1 zjGibrfJ4+hu5WdLplKg6tjBQI0zWdFmGfKsArBakO6G1ZQVlo/Lx7t2bP6BKKfbp8QkRovKmsGWl Of8nO2xBq3qxediUBG/vJTvGV8FKyEMuhen6/wxyXNEcGwUMgyFCbxmTXgmcYXo00vHIYesiBS0XL bHbnw9KU9odks9SKPXe5gkxyZ692tZ9ywDPG4lEngFYM4zb1OpC70rWxR2WsfC1oPkegzgLIlKAnf IgzYZSkyNB7QDPro12JKMG2etXQHouYc/SKy9wQMGHvP7qjLX0KHTTdyMfPPGAKGpOTOAyffn38Zq 37qt8xBQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1wJtj4-0000000DM8o-3G3O; Mon, 04 May 2026 13:52:46 +0000 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1wJtj2-0000000DM7u-1Ozh for barebox@lists.infradead.org; Mon, 04 May 2026 13:52:45 +0000 Received: from ptz.office.stw.pengutronix.de ([2a0a:edc0:0:900:1d::77] helo=[127.0.0.1]) by metis.whiteo.stw.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1wJtj0-00007P-Ny; Mon, 04 May 2026 15:52:42 +0200 Message-ID: <92783e4d-4d50-4af1-a32e-92202cbe1d89@pengutronix.de> Date: Mon, 4 May 2026 15:52:42 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird To: Sascha Hauer Cc: Marco Felsch , BAREBOX References: <20260428-env-autoprobe-v1-0-9cdedfa0752e@pengutronix.de> <20260428-env-autoprobe-v1-3-9cdedfa0752e@pengutronix.de> <12eb5638-f580-4b3b-9099-9d72ddeb4f16@pengutronix.de> From: Ahmad Fatoum Content-Language: en-US, de-DE, de-BE In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260504_065244_401058_0E85E7FD X-CRM114-Status: GOOD ( 31.55 ) X-BeenThere: barebox@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "barebox" X-SA-Exim-Connect-IP: 2607:7c80:54:3::133 X-SA-Exim-Mail-From: barebox-bounces+lore=pengutronix.de@lists.infradead.org X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on metis.whiteo.stw.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-5.2 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.2 Subject: Re: [PATCH 3/3] environment: add explicit option to allow searching for environment devices X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.whiteo.stw.pengutronix.de) Hello Sascha, On 5/4/26 3:39 PM, Sascha Hauer wrote: > On Mon, May 04, 2026 at 02:02:16PM +0200, Ahmad Fatoum wrote: >> Hello, >> >> On 5/4/26 1:35 PM, Marco Felsch wrote: >>> Hi Sascha, >>> >>> On 26-04-28, Sascha Hauer wrote: >>>> Add an explicit Kconfig option to allow searching the environment storage path >>>> based on the barebox environment partition GUID. >>>> >>>> So far this depended on CONFIG_INSECURE being set. First of all loading the >>>> barebox environment from storage is always insecure as the barebox environment >>>> doesn't have any security measures. >> >> It's possible to only allow environment loading after having verified >> that the system is in development mode for example. >> >> Autoloading the environment can't be secured as you note. >> >> >>>> The difference that comes with loading >>>> the environment from an explicitly specified storage device and autoprobing >>>> it from the available block devices is that with the former an attacker would >>>> need access to the internal storage whereas with the latter barebox could >>>> be tricked into loading an environment from an external SD card. >>>> >>>> Whether or not this is acceptable depends on the case, so ask the user for it. >>>> >>>> Real security can only be provided by not loading an environment from storage >>>> at all, but that can be controlled at compile time by disabling CONFIG_ENV_HANDLING >>>> or at runtime by security policies. >>> >>> TBH I actually don't see why this option can't follow the >>> CONFIG_INSECURE. >>> >>> Since ENV handling is enabled you do pull the HAS_INSECURE_DEFAULTS=y. >>> As you written above env handling is always insecure as of now. >>> >>> So it seems that you want to get rid of the CONFIG_INSECURE=y in your >>> setup. The only users of this CONFIG switch are global_env_autoprobe and >>> lib/random.c. Therefore my question, that I don't see why we can't stick >>> with the CONFIG_INSECURE switch. >> >> I also don't understand Sascha's motivation here. >> >> You can add global.env.autoprobe=1 to your environment to opt-in despite >> CONFIG_INSECURE being disabled. What's the new Kconfig option needed for? > > Maybe I was confused by that because it's evaluated in the wrong order. > global.env.autoprobe is evaluated in default_environment_path_get() which > is executed before the default environment is loaded. We could fix that > with the cost of calling nvvar_load() twice, once with the default > environment loaded and once again with the persistent environment > loaded. Ah.. Should load_environment() be changed, so defaultenv_load() happens before default_environment_path = default_environment_path_get(); ? > That said, I think whether or not we load the environment by part UUID > deserves its own decision, it shouldn't be hidden behind a generic > option. It has its own decision though, it's called global.env.autoprobe if it were made to work... > Also it's not consistent to claim that loading environment by > part UUID is insecure, but allowing it to be bypassed by setting > global.env.autoprobe=1, as if that would make it secure. I disagree. There is a difference: - Enabling the config option on boot up is always insecure - Setting global.env.autoprobe=1 after verifying a runtime condition can be secure if e.g. an unlock token has been verified > ENV_HANDLING_AUTOPROBE depends on ENV_HANDLING which itself selects > HAS_INSECURE_DEFAULTS which indicates that an option is selected that > has "potentially insecure defaults". Sounds consistent to me. Just pointing out we already have a magicvar for that. I am not against adding ENV_HANDLING_AUTOPROBE in principle, but I think the commit needs a better rationale why we need it when CONFIG_INSECURE and global.env.autoprobe are already there... Cheers, Ahmad > > Sascha > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |