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=-10.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham 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 B6BBCC10F11 for ; Wed, 24 Apr 2019 11:52:46 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 85348218B0 for ; Wed, 24 Apr 2019 11:52:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="ps+SLFSp" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 85348218B0 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+infradead-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=bombadil.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=bLp3IZcHQz9lSQp0hcDswFnXoLeESkl8/rio8bLZZ6M=; b=ps+SLFSpUyhb/9 rS2j8xJZ1C1HKgO+4Pggg2AGmURSEkm7h/49T+YNJVmIRWtUII8z8dQxk96F3tkW8nqQm7BdnVk9k dURIu2v3mvctn7Xd5xcaUaSalBmbUgEWbLZQCHNsIMXiPRuDjU9XTnVIldo/ulLq/YCtob4RUxha/ PAg2pj4ZMfCj9NmQAdhMfTKoHR00u9+1iVtXAMK8LPjipQJ6iK6U6EmECLDSG4nCsTX2kXvlu9zel KUKMnq5CLgkfHm0upheZ81gCNOjxDqYy3svBuFhC8BrOfnXSWiX4awuXL6BPTxvv3aSFkOHUpVaGr aO9qtckP1YrXfAS2p03A==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hJGS8-0001NB-99; Wed, 24 Apr 2019 11:52:40 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hJGS5-0001Mi-Lv for linux-arm-kernel@lists.infradead.org; Wed, 24 Apr 2019 11:52:39 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A3E60A78; Wed, 24 Apr 2019 04:52:36 -0700 (PDT) Received: from fuggles.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D2FFD3F238; Wed, 24 Apr 2019 04:52:35 -0700 (PDT) Date: Wed, 24 Apr 2019 12:52:31 +0100 From: Will Deacon To: Marc Gonzalez Subject: Re: [PATCH v2] iommu/arm-smmu: Break insecure users by disabling bypass by default Message-ID: <20190424115231.GA14829@fuggles.cambridge.arm.com> References: <20190301192017.39770-1-dianders@chromium.org> <20190404145957.GA25912@fuggles.cambridge.arm.com> <4754bcf1-6423-f1fe-64d4-da4a35b164ad@free.fr> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <4754bcf1-6423-f1fe-64d4-da4a35b164ad@free.fr> User-Agent: Mutt/1.11.1+86 (6f28e57d73f2) () X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190424_045237_717216_218270CA X-CRM114-Status: GOOD ( 20.00 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Douglas Anderson , Linux ARM Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Apr 24, 2019 at 01:36:58PM +0200, Marc Gonzalez wrote: > On 04/04/2019 17:00, Will Deacon wrote: > > > On Fri, Mar 01, 2019 at 11:20:17AM -0800, Douglas Anderson wrote: > > > >> If you're bisecting why your peripherals stopped working, it's > >> probably this CL. Specifically if you see this in your dmesg: > >> Unexpected global fault, this could be serious > >> ...then it's almost certainly this CL. > >> > >> Running your IOMMU-enabled peripherals with the IOMMU in bypass mode > >> is insecure and effectively disables the protection they provide. > >> There are few reasons to allow unmatched stream bypass, and even fewer > >> good ones. > >> > >> This patch starts the transition over to make it much harder to run > >> your system insecurely. Expected steps: > >> > >> 1. By default disable bypass (so anyone insecure will notice) but make > >> it easy for someone to re-enable bypass with just a KConfig change. > >> That's this patch. > >> > >> 2. After people have had a little time to come to grips with the fact > >> that they need to set their IOMMUs properly and have had time to > >> dig into how to do this, the KConfig will be eliminated and bypass > >> will simply be disabled. Folks who are truly upset and still > >> haven't fixed their system can either figure out how to add > >> 'arm-smmu.disable_bypass=n' to their command line or revert the > >> patch in their own private kernel. Of course these folks will be > >> less secure. > >> > >> Suggested-by: Robin Murphy > >> Signed-off-by: Douglas Anderson > >> --- > >> > >> Changes in v2: > >> - Flipped default to 'yes' and changed comments a lot. > >> > >> drivers/iommu/Kconfig | 25 +++++++++++++++++++++++++ > >> drivers/iommu/arm-smmu.c | 3 ++- > >> 2 files changed, 27 insertions(+), 1 deletion(-) > > > > Cheers, I'll pick this one up for 5.2. > > Hello Will, > > You haven't pushed this patch out to linux-next AFAICT. > > Is that expected? It's on my branch for Joerg: https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git/log/?h=for-joerg/arm-smmu/updates which I'll send to him today. My SMMU stuff doesn't go directly into -next. Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel