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 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D0C5BC433EF for ; Thu, 23 Dec 2021 13:45:18 +0000 (UTC) Received: from localhost ([::1]:58560 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1n0OPF-00084A-D0 for qemu-devel@archiver.kernel.org; Thu, 23 Dec 2021 08:45:17 -0500 Received: from eggs.gnu.org ([209.51.188.92]:38426) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1n0ONm-0007El-1I for qemu-devel@nongnu.org; Thu, 23 Dec 2021 08:43:46 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:53579) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1n0ONi-0005EG-Jm for qemu-devel@nongnu.org; Thu, 23 Dec 2021 08:43:44 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1640267021; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=j6u/Y8dnM8g1Ct4ZKexeby7UXE26h0EJhMaNPVTf1t0=; b=hHxo2fG8jQLFj/5k1fTi4CILkiPFs4LiJAdE9Anh1N48FgQQVJn0tcXGaIHrOpMGUbS6RX MISgD0peky4l7J2TcRDujOf6QAHi3pLHnsX5TVzLOuQNThi7q3gag6WZW4NL4iZApWdwOP UEKw9KAQB4ACEtpzTg4KtZ3a6Y7hu58= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-250-tQzAntiqNoqij8A2WydkQw-1; Thu, 23 Dec 2021 08:43:38 -0500 X-MC-Unique: tQzAntiqNoqij8A2WydkQw-1 Received: by mail-wm1-f71.google.com with SMTP id az11-20020a05600c600b00b00345c4309bccso1862832wmb.5 for ; Thu, 23 Dec 2021 05:43:38 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to; bh=j6u/Y8dnM8g1Ct4ZKexeby7UXE26h0EJhMaNPVTf1t0=; b=MWn/dInRYkEmbaD1T5rfUkxDV5AlgNQWELj8fUiqLaI0NOcd2lwTF5+/7LD8lFCVdr eNc1pnzNZiLQBonto/aJ0QXGCgL1OgUJghMxNQ1NiGXsNwl558OXNkz3BES8KiDvVfAX 9pIqxbtQdOirbwbzq0b73SXrT1aVplOD+Xd/WfWm1ah+B3L6b4pbw4arTRPqUS0UAmDK Sp0qI0m33gtJJNa33eWDIvLviEY2vWtyKvwnjqjfq62DkdXcXVLtZ8muSwsMYH55yRcU VwTFClJE+HXRlX3/yZRFnyPhZUtr1Q6quGukomCMD2C45hCW8LuNriwnns3m1qyfwcsW zsGA== X-Gm-Message-State: AOAM532t/7IWhbRib+EHzOakIEnxKJXU4yI7pZgPsnhIPsTl5rx/ToLl LHZg/r6RxmK9+qlZnd0I+CXIJWRdwoqfuI6GYzEoYy1TgQ5iBCqejYBieX9O+uVwIDIGsW32V9Q bQrwq6yebQ9Ln01I= X-Received: by 2002:a5d:54c8:: with SMTP id x8mr1756574wrv.299.1640267017678; Thu, 23 Dec 2021 05:43:37 -0800 (PST) X-Google-Smtp-Source: ABdhPJyEznWFeQMnBuA+EBogBTr7ArqvZx41RqrJmfYmNYvWJUD6hZUclaTv7rxrVuzEHEyxCBa/lw== X-Received: by 2002:a5d:54c8:: with SMTP id x8mr1756555wrv.299.1640267017463; Thu, 23 Dec 2021 05:43:37 -0800 (PST) Received: from redhat.com ([2.55.1.37]) by smtp.gmail.com with ESMTPSA id e13sm8247649wmq.10.2021.12.23.05.43.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 23 Dec 2021 05:43:37 -0800 (PST) Date: Thu, 23 Dec 2021 08:43:32 -0500 From: "Michael S. Tsirkin" To: Mauro Matteo Cascella Subject: Re: [PATCH] acpi: validate hotplug selector on access Message-ID: <20211223083646-mutt-send-email-mst@kernel.org> References: <20211221144852.589983-1-mst@redhat.com> <20211222151922-mutt-send-email-mst@kernel.org> <20211222154841-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 In-Reply-To: Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mst@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=mst@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.203, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: QEMU Developers , Prasad Pandit , Alexander Bulekov , Paolo Bonzini , Ani Sinha , Igor Mammedov , Philippe =?iso-8859-1?Q?Mathieu-Daud=E9?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, Dec 23, 2021 at 10:58:14AM +0100, Mauro Matteo Cascella wrote: > Hi, > > On Wed, Dec 22, 2021 at 9:52 PM Michael S. Tsirkin wrote: > > > > On Wed, Dec 22, 2021 at 09:27:51PM +0100, Philippe Mathieu-Daudé wrote: > > > On Wed, Dec 22, 2021 at 9:20 PM Michael S. Tsirkin wrote: > > > > On Wed, Dec 22, 2021 at 08:19:41PM +0100, Philippe Mathieu-Daudé wrote: > > > > > +Mauro & Alex > > > > > > > > > > On 12/21/21 15:48, Michael S. Tsirkin wrote: > > > > > > When bus is looked up on a pci write, we didn't > > > > > > validate that the lookup succeeded. > > > > > > Fuzzers thus can trigger QEMU crash by dereferencing the NULL > > > > > > bus pointer. > > > > > > > > > > > > Fixes: b32bd763a1 ("pci: introduce acpi-index property for PCI device") > > > > > > Cc: "Igor Mammedov" > > > > > > Fixes: https://gitlab.com/qemu-project/qemu/-/issues/770 > > > > > > Signed-off-by: Michael S. Tsirkin > > > > > > > > > > It seems this problem is important enough to get a CVE assigned. > > > > > > > > Guest root can crash guest. > > > > I don't see why we would assign a CVE. > > > > > > Well thinking about downstream distributions, if there is a CVE assigned, > > > it helps them to have it written in the commit. Maybe I am mistaken. > > > > > > Unrelated but it seems there is a coordination problem with the > > > qemu-security@ list, > > > if this isn't a security issue, why was a CVE requested? > > > > Right. I don't think a priveleged user crashing VM warrants a CVE, > > it can just halt a CPU or whatever. Just cancel the CVE request pls. > > While I agree with you that this is kind of borderline and I expressed > similar concerns in the past, I was told that: > > 1) root guest users are not necessarily trustworthy (from the host perspective). > 2) NULL pointer deref and similar issues caused by an > ill-handled/error condition are CVE worthy, even if triggered by root. > 3) In other cases, DoS triggered by root is not a security issue > because it's an expected behavior and not an ill-handled/error > condition (think of assert failures, for example). > > In other words, "ill-handled condition" is the crucial factor that > makes a bug CVE worthy or not. I guess the point is that a downstream might have a slightly different code path where it would be more serious ... OK then, not a big deal for me. So what's the CVE # then? > +Prasad, can you shed some light on this? Is my understanding correct? > > Also, please note that we regularly get CVE requests for bugs like > this and many CVEs have been assigned in the past. Of course that > doesn't mean we can't change things going forward, but I think we > should make it clear (probably here: > https://www.qemu.org/docs/master/system/security.html) that these > kinds of bugs are not eligible for CVE assignment. That would be good, yes. > > > > > Mauro, please update us when you get the CVE number. > > > > > Michael, please amend the CVE number before committing the fix. > > > > > > > > > > FWIW Paolo asked every fuzzed bug reproducer to be committed > > > > > as qtest, see tests/qtest/fuzz*c. Alex has a way to generate > > > > > reproducer in plain C. > > > > > > > > > > Regards, > > > > > > > > > > Phil. > > > > > > > > -- > Mauro Matteo Cascella > Red Hat Product Security > PGP-Key ID: BB3410B0