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 9A40AC00140 for ; Wed, 10 Aug 2022 14:13:45 +0000 (UTC) Received: from localhost ([::1]:41970 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oLmSu-0007LH-Kf for qemu-devel@archiver.kernel.org; Wed, 10 Aug 2022 10:13:44 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59148) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oLlyD-0000hk-Kr for qemu-devel@nongnu.org; Wed, 10 Aug 2022 09:42:05 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:27656) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oLly8-0008Sx-HB for qemu-devel@nongnu.org; Wed, 10 Aug 2022 09:41:58 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1660138913; 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:in-reply-to:in-reply-to: references:references; bh=5Dl8xadVKUUj6dIItnGpYgWXIiFCQLO4gx1UslVj92U=; b=A024UsbU1zY0b/3G2uhGMnKwtKq23cDa5O8iQbEaNZA09bHsTqIw/oi9zg9kb0eFYe7ywe Li5hKB4Nn0xHptNGWK2GovYh9B9osCt+xiud5LGo9SxLYec0yQGuWDAq3R5KKaca6DdUHE fQJ4m8be5Qg3AbbfJedkT706dfxZZXc= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-146-8U6Bc4E0NFGm6EZRR6Uw2w-1; Wed, 10 Aug 2022 09:41:50 -0400 X-MC-Unique: 8U6Bc4E0NFGm6EZRR6Uw2w-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id DD16885A596; Wed, 10 Aug 2022 13:41:49 +0000 (UTC) Received: from redhat.com (unknown [10.33.36.20]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 614341415125; Wed, 10 Aug 2022 13:41:49 +0000 (UTC) Date: Wed, 10 Aug 2022 14:41:46 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: danko babro Cc: qemu-devel@nongnu.org Subject: Re: Using QEMU for VRChat Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/2.2.6 (2022-06-05) X-Scanned-By: MIMEDefang 2.85 on 10.11.54.7 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: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 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: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, Aug 10, 2022 at 01:06:59PM +0200, danko babro wrote: > Dear QEMU dev team, > Recently a game called VRChat got a security update, implementing Easy Anti > Cheat into their game (pretty much spyware that logs everything happening > on the users PC) which made me want to install their game on a virtual > machine. > > The problem now is, that the anti cheat detects if the user is playing on a > virtual machine, but in the official documentation by their dev team there > is a workaround for that, specifically for QEMU, that can be found here: > > https://docs.vrchat.com/docs/using-vrchat-in-a-virtual-machine > > I simply cant understand what that code (on the given website) does. Does > it open up a backdoor for the anti cheat to access my real pc? > > Is QEMU in general a good solution for when it comes to protecting my > actual PC from threats like these, or any other sorts of viruses for > example, since it uses a kernel based VM. The targetted recommendation of -cpu ....,hv-vendor-id=0123756792CD is essentially harmless. It merely changes one CPUID register so that the anti cheat code no longer believe it is running in a HyperV VM. It wouldn't fool a really determined anti cheat code chcker, because there are a great many ways to detect you're inside a VM. Evidentially this particular code though only cares about a CPUID value. I the vendor ID value could be essentially anything you want it to be, not just this one specific value - just has to be different from the default. This is not opening a backdoor to your host OS. The more general recommendation simply enables all hyperv enlightenments. This appears to be sufficient to again fool the anti cheat code, while having the added benefit of likely improving performance. Again, this is not opening a backdoor to your host OS. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|