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=-5.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 21A5AC2D0E2 for ; Thu, 24 Sep 2020 16:45:57 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id BF6322068D for ; Thu, 24 Sep 2020 16:45:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="DEPNGQMj" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BF6322068D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=digikod.net Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=9urlb8vYMbThuYfey32W2/bnoGsPNmHTdolQy5AzC+0=; b=DEPNGQMjkfnLs9h2qsGelV7Jm eQlbnlYicyW/L+HyNRgj3ZcnnXhY9fTamXq+90FoAzznc6BnS9IrqCUT5CY0TIXjMmZV3Dz/EplfA 2roFthCYAdDRh0rbDRe/0RjJd2ELSWYDeOXn/cTtZw0G9BQBe/WpwYseSq6UAebILw9h0+ic1yb34 cJiIOGtAYXbYO+eli3buGkxLZuUMNZFYSdhO2JLC8kv+jln+MtNQ3CzwA6QBb3bSHK8Wo+9piNzqI aU5czmc3hnXDlCJqpVpzyAtTtwkAmBgzzxfj5EyEGZ4OBU/noCt+dBdAoIHJL+ZwZdl6xna1hh2pg mgjvh6ujg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kLUMR-00067N-O9; Thu, 24 Sep 2020 16:44:47 +0000 Received: from smtp-8faa.mail.infomaniak.ch ([83.166.143.170]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kLUMO-000654-Sr for linux-arm-kernel@lists.infradead.org; Thu, 24 Sep 2020 16:44:46 +0000 Received: from smtp-2-0001.mail.infomaniak.ch (unknown [10.5.36.108]) by smtp-3-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4By19B01Y1zlhTqt; Thu, 24 Sep 2020 18:44:30 +0200 (CEST) Received: from ns3096276.ip-94-23-54.eu (unknown [94.23.54.103]) by smtp-2-0001.mail.infomaniak.ch (Postfix) with ESMTPA id 4By1972FNszlh8Yx; Thu, 24 Sep 2020 18:44:27 +0200 (CEST) Subject: Re: [PATCH v2 0/4] [RFC] Implement Trampoline File Descriptor To: Pavel Machek , "Madhavan T. Venkataraman" References: <210d7cd762d5307c2aa1676705b392bd445f1baa> <20200922215326.4603-1-madvenka@linux.microsoft.com> <20200923084232.GB30279@amd> <34257bc9-173d-8ef9-0c97-fb6bd0f69ecb@linux.microsoft.com> <20200923205156.GA12034@duo.ucw.cz> From: =?UTF-8?Q?Micka=c3=abl_Sala=c3=bcn?= Message-ID: Date: Thu, 24 Sep 2020 18:44:26 +0200 User-Agent: MIME-Version: 1.0 In-Reply-To: <20200923205156.GA12034@duo.ucw.cz> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200924_124445_069532_38769B2C X-CRM114-Status: GOOD ( 17.89 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: fweimer@redhat.com, mark.rutland@arm.com, kernel-hardening@lists.openwall.com, linux-api@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, oleg@redhat.com, linux-security-module@vger.kernel.org, David.Laight@ACULAB.COM, luto@kernel.org, linux-fsdevel@vger.kernel.org, linux-integrity@vger.kernel.org, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 23/09/2020 22:51, Pavel Machek wrote: > Hi! > >>>> Scenario 2 >>>> ---------- >>>> >>>> We know what code we need in advance. User trampolines are a good example of >>>> this. It is possible to define such code statically with some help from the >>>> kernel. >>>> >>>> This RFC addresses (2). (1) needs a general purpose trusted code generator >>>> and is out of scope for this RFC. >>> >>> This is slightly less crazy talk than introduction talking about holes >>> in W^X. But it is very, very far from normal Unix system, where you >>> have selection of interpretters to run your malware on (sh, python, >>> awk, emacs, ...) and often you can even compile malware from sources. >>> >>> And as you noted, we don't have "a general purpose trusted code >>> generator" for our systems. >>> >>> I believe you should simply delete confusing "introduction" and >>> provide details of super-secure system where your patches would be >>> useful, instead. >> >> This RFC talks about converting dynamic code (which cannot be authenticated) >> to static code that can be authenticated using signature verification. That >> is the scope of this RFC. >> >> If I have not been clear before, by dynamic code, I mean machine code that is >> dynamic in nature. Scripts are beyond the scope of this RFC. >> >> Also, malware compiled from sources is not dynamic code. That is orthogonal >> to this RFC. If such malware has a valid signature that the kernel permits its >> execution, we have a systemic problem. >> >> I am not saying that script authentication or compiled malware are not problems. >> I am just saying that this RFC is not trying to solve all of the security problems. >> It is trying to define one way to convert dynamic code to static code to address >> one class of problems. > > Well, you don't have to solve all problems at once. > > But solutions have to exist, and AFAIK in this case they don't. You > are armoring doors, but ignoring open windows. FYI, script execution is being addressed (for the kernel part) by this patch series: https://lore.kernel.org/lkml/20200924153228.387737-1-mic@digikod.net/ > > Or very probably you are thinking about something different than > normal desktop distros (Debian 10). Because on my systems, I have > python, gdb and gcc... It doesn't make sense for a tailored security system to leave all these tools available to an attacker. > > It would be nice to specify what other pieces need to be present for > this to make sense -- because it makes no sense on Debian 10. Not all kernel features make sense for a generic/undefined usage, especially specific security mechanisms (e.g. SELinux, Smack, Tomoyo, SafeSetID, LoadPin, IMA, IPE, secure/trusted boot, lockdown, etc.), but they can still be definitely useful. > > Best regards, > Pavel > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel