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=-5.3 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,USER_AGENT_SANE_1 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 DE0C6C433E2 for ; Mon, 7 Sep 2020 10:36:33 +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 5557320738 for ; Mon, 7 Sep 2020 10:36:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="HmSpKFjy" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5557320738 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com 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:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=+IxDiB5YHdFj6yXjHhErCKASSJre9jr8vOVSpanNuYU=; b=HmSpKFjykRweAeZoqgU2lUaVm FXEG+ECZpgda8c+jHoKN5sdF9SPl6BpxqOupiC6tCU/biPfKZ148Ecs6DFyEZLQn35p9qEpE8ymAF EMxrUbR+uNMJxX4bhlLXaDFO5hahheAvXzEy/UyuBNQk5cuFPd+Lg4GDAHyy6p9RG21NFf7Qkw0CR XmNDehFHd3uP2XjeQyJlNFmNk0mqRmHC84gELqIS5F02ufczaOWZPHob3ruw9Sb7dxfpke0igjQv/ k16ORa0O2C8aF+EHgTiybojQpyl1Lil2yzOWrV1JaLPmwwrd1ByfmbtOrAOKcz9fdUqcpAuv+nF2v 3GU+CfUpw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kFEUe-0006x0-CN; Mon, 07 Sep 2020 10:35:24 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kFEUb-0006w4-Cl for linux-arm-kernel@lists.infradead.org; Mon, 07 Sep 2020 10:35:22 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 2B137106F; Mon, 7 Sep 2020 03:35:20 -0700 (PDT) Received: from arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id CCDF53F66E; Mon, 7 Sep 2020 03:35:18 -0700 (PDT) Date: Mon, 7 Sep 2020 11:35:16 +0100 From: Dave Martin To: Boyan Karatotev Subject: Re: [PATCH v2 3/4] kselftests/arm64: add PAuth test for whether exec() changes keys Message-ID: <20200907103516.GO6642@arm.com> References: <20200831110450.30188-1-boyan.karatotev@arm.com> <20200831110450.30188-4-boyan.karatotev@arm.com> <20200902170854.GK6642@arm.com> <926691e4-1990-207e-bcb9-40ab6d3b0fa0@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <926691e4-1990-207e-bcb9-40ab6d3b0fa0@arm.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200907_063521_519225_44A221A6 X-CRM114-Status: GOOD ( 26.84 ) 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: Will Deacon , boian4o1@gmail.com, Catalin Marinas , linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, amit.kachhap@arm.com, vincenzo.frascino@arm.com, Shuah Khan , 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 Thu, Sep 03, 2020 at 11:48:37AM +0100, Boyan Karatotev wrote: > On 02/09/2020 18:08, Dave Martin wrote: > > On Mon, Aug 31, 2020 at 12:04:49PM +0100, Boyan Karatotev wrote: > >> +/* > >> + * fork() does not change keys. Only exec() does so call a worker program. > >> + * Its only job is to sign a value and report back the resutls > >> + */ > >> +TEST(exec_unique_keys) > >> +{ > > > > The kernel doesn't guarantee that keys are unique. > > > > Can we present all the "unique keys" wording differently, say > > > > exec_key_collision_likely() > > I agree that this test's name is a bit out of place. I would rather have > it named "exec_changed_keys" though. > > > Otherwise people might infer from this test code that the keys are > > supposed to be truly unique and start reporting bugs on the kernel. > > > > I can't see an obvious security argument for unique keys (rather, the > > keys just need to be "unique enough". That's the job of > > get_random_bytes().) > > The "exec_unique_keys" test only checks that the keys changed after an > exec() which I think the name change would reflect. > > The thing with the "single_thread_unique_keys" test is that the kernel > says the the keys will be random. Yes, there is no uniqueness guarantee > but I'm not sure how to phrase it differently. There is some minuscule > chance that the keys end up the same, but for this test I pretend this > will not happen. Would changing up the comments and the failure message > communicate this? Maybe substitute "unique" for "different" and say how > many keys clashed? Yes, something like that seems reasonable. Cheers ---Dave _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel