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 578ABF46137 for ; Mon, 23 Mar 2026 14:57:24 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1w4gi2-0000A9-Lc; Mon, 23 Mar 2026 10:56:50 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1w4ghy-00008H-CF for qemu-devel@nongnu.org; Mon, 23 Mar 2026 10:56:46 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1w4ghv-0006tP-Nw for qemu-devel@nongnu.org; Mon, 23 Mar 2026 10:56:45 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1774277801; h=from:from:reply-to: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=AB+sKi8OYhoJimMrdxZXtUS/CmESeSffeocO8B1EHaw=; b=acn1/Acu1z6P+ye7fm1xSvZGk3xYlvkmsvMfVUtTTtnS58ZHN9ZkahsrANsNoJe9cbm/LB 2LQLYaFQg40SNC7D+DMdo+xtO3wHdAwodjPbD2Q7Rq4t8dRB0NnGL2CORQqee4h8ABnnM/ mRIiYpmtv4CTcoyd2LxhsPCDW9gKgGM= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-194-12Vzaal6Pues7JuxdTHUsA-1; Mon, 23 Mar 2026 10:56:39 -0400 X-MC-Unique: 12Vzaal6Pues7JuxdTHUsA-1 X-Mimecast-MFC-AGG-ID: 12Vzaal6Pues7JuxdTHUsA_1774277798 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (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 mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 1EDB51944EB0; Mon, 23 Mar 2026 14:56:38 +0000 (UTC) Received: from redhat.com (unknown [10.45.224.227]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 18A9E1800107; Mon, 23 Mar 2026 14:56:34 +0000 (UTC) Date: Mon, 23 Mar 2026 14:56:30 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: "Michael S. Tsirkin" Cc: Peter Maydell , Junjie Cao , qemu-devel@nongnu.org, jasowang@redhat.com, yuri.benditovich@daynix.com, akihiko.odaki@daynix.com, qemu-stable@nongnu.org Subject: Re: [PATCH] virtio-net: validate RSS indirections_len in post_load Message-ID: References: <20260323131531.1976-1-junjie.cao@intel.com> <20260323095706-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260323095706-mutt-send-email-mst@kernel.org> User-Agent: Mutt/2.2.14 (2025-02-20) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-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: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Mon, Mar 23, 2026 at 09:57:24AM -0400, Michael S. Tsirkin wrote: > On Mon, Mar 23, 2026 at 01:53:53PM +0000, Peter Maydell wrote: > > On Mon, 23 Mar 2026 at 13:43, Daniel P. Berrangé wrote: > > > > > > On Mon, Mar 23, 2026 at 09:15:31PM +0800, Junjie Cao wrote: > > > > virtio_net_handle_rss() enforces that indirections_len is a non-zero > > > > power of two no larger than VIRTIO_NET_RSS_MAX_TABLE_LEN, but > > > > virtio_net_rss_post_load() applies none of these checks to values > > > > restored from the migration stream. > > > > > > > > A crafted migration stream can set indirections_len to 0. Even if it > > > > > > The migration stream originating from the source QEMU is trusted. > > > > Is it? In https://www.qemu.org/docs/master/system/security.html we say: > > > > # The following entities are untrusted, meaning that they may be buggy > > # or malicious: > > > > # * Guest > > # * User-facing interfaces (e.g. VNC, SPICE, WebSocket) > > # * Network protocols (e.g. NBD, live migration) > > # * User-supplied files (e.g. disk images, kernels, device trees) > > # * Passthrough devices (e.g. PCI, USB) > > > > which explicitly lists "live migration" as an untrusted entity. > > > > I would definitely be extremely cautious about having a threat > > model where I had to distrust inbound migration data, but the > > above does suggest we aim to handle that, and we have I think > > in the past taken patches which add sanity-checking to the > > migration data. > > And we even assigned a low priority CVEs to these. Do you have an example of that ? With regards, Daniel -- |: https://berrange.com ~~ https://hachyderm.io/@berrange :| |: https://libvirt.org ~~ https://entangle-photo.org :| |: https://pixelfed.art/berrange ~~ https://fstop138.berrange.com :|