From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail02.groups.io (mail02.groups.io [66.175.222.108]) by spool.mail.gandi.net (Postfix) with ESMTPS id D9731D80685 for ; Thu, 14 Dec 2023 15:31:35 +0000 (UTC) DKIM-Signature: a=rsa-sha256; bh=WIH1M5oj9kbA7GialQBx5Py+MDLVDbFm7BjEJvX1AT0=; c=relaxed/simple; d=groups.io; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version:In-Reply-To:Precedence:List-Subscribe:List-Help:Sender:List-Id:Mailing-List:Delivered-To:Reply-To:List-Unsubscribe-Post:List-Unsubscribe:Content-Type:Content-Disposition; s=20140610; t=1702567894; v=1; b=Jwb2N4VTmrI1z+k8u+1BaVEgatpo60Pp7UFnKxvE0c1TdfMI3d9ipPjSDgZ2tiZrdPeeESu1 LjRT6gqkV9mkEH4I1u7hKXfp0zCM7nEiCTkzSPHvn43KWDurvB/++VhYo/EcJbeQ40qaa8HYPMl yeuq705ocuAMncKYK6FzetJE= X-Received: by 127.0.0.2 with SMTP id zrpqYY7687511xUdaNsBBfmO; Thu, 14 Dec 2023 07:31:34 -0800 X-Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by mx.groups.io with SMTP id smtpd.web11.25360.1702567893802087703 for ; Thu, 14 Dec 2023 07:31:34 -0800 X-Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-644-9F8awQ_eNia1pOQ-EloaBw-1; Thu, 14 Dec 2023 10:31:30 -0500 X-MC-Unique: 9F8awQ_eNia1pOQ-EloaBw-1 X-Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 196E0833B64; Thu, 14 Dec 2023 15:31:28 +0000 (UTC) X-Received: from sirius.home.kraxel.org (unknown [10.39.192.126]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A863DC15E78; Thu, 14 Dec 2023 15:31:27 +0000 (UTC) X-Received: by sirius.home.kraxel.org (Postfix, from userid 1000) id 5434A18003AB; Thu, 14 Dec 2023 16:31:24 +0100 (CET) Date: Thu, 14 Dec 2023 16:31:24 +0100 From: "Gerd Hoffmann" To: Laszlo Ersek Cc: devel@edk2.groups.io, mike.maslenkin@gmail.com, Jiewen Yao , Ard Biesheuvel , oliver@redhat.com Subject: Re: [edk2-devel] [PATCH v2 1/1] OvmfPkg/VirtNorFlashDxe: sanity-check variables Message-ID: <72vsvymwepkdu7m7b3uy5wxifxggegezwi44zkascp3weya7ci@afbg44yzs3ov> References: <20231207094404.270381-1-kraxel@redhat.com> MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.8 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Precedence: Bulk List-Subscribe: List-Help: Sender: devel@edk2.groups.io List-Id: Mailing-List: list devel@edk2.groups.io; contact devel+owner@edk2.groups.io Reply-To: devel@edk2.groups.io,kraxel@redhat.com List-Unsubscribe-Post: List-Unsubscribe=One-Click List-Unsubscribe: X-Gm-Message-State: 0UCU5BdnSicjPQaDTIsitifZx7686176AA= Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-GND-Status: LEGIT Authentication-Results: spool.mail.gandi.net; dkim=pass header.d=groups.io header.s=20140610 header.b=Jwb2N4VT; spf=pass (spool.mail.gandi.net: domain of bounce@groups.io designates 66.175.222.108 as permitted sender) smtp.mailfrom=bounce@groups.io; dmarc=fail reason="SPF not aligned (relaxed), DKIM not aligned (relaxed)" header.from=redhat.com (policy=none) Hi, > The general idea is, once we don't trust the varstore, there cannot be > a *single* unchecked addition in the code. (Unless we can *prove* that > overflow is impossible.) There are some cases where we add a small, constant number to a value we know is smaller than VariableStoreHeader->Size. I don't see how those can overflow, given that varstore flash typically is an order of magnitude smaller than MAX_UINT32 (unless VariableStoreHeader->Size is corrupted, but then we have bigger problems anyway ...). take care, Gerd -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#112540): https://edk2.groups.io/g/devel/message/112540 Mute This Topic: https://groups.io/mt/103031342/7686176 Group Owner: devel+owner@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [rebecca@openfw.io] -=-=-=-=-=-=-=-=-=-=-=-