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 C2B4DD800D7 for ; Fri, 12 Jan 2024 09:47:50 +0000 (UTC) DKIM-Signature: a=rsa-sha256; bh=ot/tafeeAyxwcODo7h2EfJt/3KGAe24QPLu8a2x0ks4=; c=relaxed/simple; d=groups.io; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From:In-Reply-To:Precedence:List-Subscribe:List-Help:Sender:List-Id:Mailing-List:Delivered-To:Reply-To:List-Unsubscribe-Post:List-Unsubscribe:Content-Language:Content-Type:Content-Transfer-Encoding; s=20140610; t=1705052869; v=1; b=D7Iie7i0jkYxUL/Z7cooJxLNIIIltuGhyc1sZ8AiA82OfiEWukB8RUAbXsHEZeUdGwGdRtsz e1YmffyaiMpjfQqYKPr+iZC/rSZ5YlEOdQRBJrv9rX0XknrnmfYDKV9meLNKVadFdbNnE5VXAq6 j5pWhlgemMvqPpR8hvgOV1IM= X-Received: by 127.0.0.2 with SMTP id 94BrYY7687511xTZ5XoZHR3I; Fri, 12 Jan 2024 01:47:49 -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.web11.3869.1705052868862682967 for ; Fri, 12 Jan 2024 01:47:49 -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-240-tzf81OelO3uU6k6lzs78Mg-1; Fri, 12 Jan 2024 04:47:45 -0500 X-MC-Unique: tzf81OelO3uU6k6lzs78Mg-1 X-Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (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 8FB8785A58E; Fri, 12 Jan 2024 09:47:45 +0000 (UTC) X-Received: from [10.39.192.105] (unknown [10.39.192.105]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A7354492BFD; Fri, 12 Jan 2024 09:47:44 +0000 (UTC) Message-ID: <0ccd39db-ce5c-e7c7-192e-d67f939b5dad@redhat.com> Date: Fri, 12 Jan 2024 10:47:43 +0100 MIME-Version: 1.0 Subject: Re: [edk2-devel] [PATCH 1/1] OvmfPkg/VirtNorFlashDxe: fix shadowbuffer reads To: Gerd Hoffmann , devel@edk2.groups.io Cc: oliver@redhat.com, Jiewen Yao , Ard Biesheuvel References: <20240111133627.156839-1-kraxel@redhat.com> From: "Laszlo Ersek" In-Reply-To: <20240111133627.156839-1-kraxel@redhat.com> X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.10 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,lersek@redhat.com List-Unsubscribe-Post: List-Unsubscribe=One-Click List-Unsubscribe: X-Gm-Message-State: AXRFY72WrIYFNQVbYKierrNUx7686176AA= Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-GND-Status: LEGIT Authentication-Results: spool.mail.gandi.net; dkim=pass header.d=groups.io header.s=20140610 header.b=D7Iie7i0; 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) On 1/11/24 14:36, Gerd Hoffmann wrote: > In some cases (specifically when the flash update region is > small but crosses a multiple of P30_MAX_BUFFER_SIZE_IN_BYTES) > NorFlashWriteSingleBlock reads only one instead of two > P30_MAX_BUFFER_SIZE_IN_BYTES blocks into the shadow buffer. >=20 > That leads to random crap being written to the second block, > which in turn can corrupt both the variable store and the > FTW work space. >=20 > This patch fixes the calculation. >=20 > Signed-off-by: Gerd Hoffmann > --- > OvmfPkg/VirtNorFlashDxe/VirtNorFlash.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) >=20 > diff --git a/OvmfPkg/VirtNorFlashDxe/VirtNorFlash.c b/OvmfPkg/VirtNorFlas= hDxe/VirtNorFlash.c > index 1afd60ce66eb..cdc809d75e3d 100644 > --- a/OvmfPkg/VirtNorFlashDxe/VirtNorFlash.c > +++ b/OvmfPkg/VirtNorFlashDxe/VirtNorFlash.c > @@ -566,7 +566,7 @@ NorFlashWriteSingleBlock ( > Instance, > Lba, > Offset & ~BOUNDARY_OF_32_WORDS, > - (*NumBytes | BOUNDARY_OF_32_WORDS) + 1, > + (((Offset & BOUNDARY_OF_32_WORDS) + *NumBytes) | BOUNDARY= _OF_32_WORDS) + 1, > Instance->ShadowBuffer > ); > if (EFI_ERROR (Status)) { This patch looks like the output of an excellent bug analysis. I'll need more time to review this. If you have a ticket with the analysis captured (actual numbers, debugging logs, a concrete backtrace / call chain triggering the issue, etc), I'd appreciate a reference. (Perhaps include some of the key items in the commit message too?) Thanks Laszlo -=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#113705): https://edk2.groups.io/g/devel/message/113705 Mute This Topic: https://groups.io/mt/103661868/7686176 Group Owner: devel+owner@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/leave/12367111/7686176/19134562= 12/xyzzy [rebecca@openfw.io] -=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-