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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 16268C433F5 for ; Tue, 26 Oct 2021 08:43:53 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 924A960F0F for ; Tue, 26 Oct 2021 08:43:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 924A960F0F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:48142 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mfI3j-0000S9-I8 for qemu-devel@archiver.kernel.org; Tue, 26 Oct 2021 04:43:51 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:56496) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mfI2T-00089q-IV for qemu-devel@nongnu.org; Tue, 26 Oct 2021 04:42:33 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:44274) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mfI2R-0001F1-G2 for qemu-devel@nongnu.org; Tue, 26 Oct 2021 04:42:33 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1635237750; 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=n2eU8FWqkWNlOBo4IFuR74qIfzhjij1b5OHJEFj9dOM=; b=gDHsF5cfza22dbwCrEv/NpF9yAOtpk63mu6mOTUpP5omYdCtE7yHI+tyDbj1aT4K5p9iGl 6OSFkLsMHGQKDwoXKeW67dX502V2pNSl7ohUgnVC1h48AbpCdqdJSDVTk5TBgc0VEywqbw 92+U58CaKsPamxbnMe+RNA9fPZXjh8M= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-61-CvNCg-HGM-mc29H8ogalsw-1; Tue, 26 Oct 2021 04:42:13 -0400 X-MC-Unique: CvNCg-HGM-mc29H8ogalsw-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 27904657; Tue, 26 Oct 2021 08:42:12 +0000 (UTC) Received: from redhat.com (unknown [10.39.195.123]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 8EA051002D6A; Tue, 26 Oct 2021 08:42:07 +0000 (UTC) Date: Tue, 26 Oct 2021 09:42:05 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Alexander Graf Subject: Re: [PATCH v4] isa-applesmc: provide OSK forwarding on Apple hosts Message-ID: References: <20211022161448.81579-1-yaroshchuk2000@gmail.com> <394b94ad-3de6-2dfb-4aaf-344dcef8ec18@csgraf.de> <81e13473-7bfc-4e32-98ef-c0df717f3b0f@csgraf.de> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/2.0.7 (2021-05-04) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=berrange@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 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_LOW=-0.7, RCVD_IN_MSPIKE_H4=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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: Phil Dennis-Jordan , Pedro =?utf-8?Q?To=CC=82rres?= , Vladislav Yaroshchuk , suse@csgraf.de, f4bug@amsat.org, qemu-devel@nongnu.org, r.bolshakov@yadro.com, "Gabriel L. Somlo" , Paolo Bonzini , laurent@vivier.eu Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Mon, Oct 25, 2021 at 09:45:35PM +0200, Alexander Graf wrote: > > On 25.10.21 17:10, Daniel P. Berrangé wrote: > > On Mon, Oct 25, 2021 at 04:53:57PM +0200, Alexander Graf wrote: > > > On 25.10.21 16:47, Daniel P. Berrangé wrote: > > > > On Mon, Oct 25, 2021 at 04:42:22PM +0200, Alexander Graf wrote: > > > > > On 25.10.21 16:22, Daniel P. Berrangé wrote: > > > > > > On Mon, Oct 25, 2021 at 12:13:32PM +0200, Alexander Graf wrote: > > > > > > > On 22.10.21 18:14, Vladislav Yaroshchuk wrote: > > > > > > > > On Apple hosts we can read AppleSMC OSK key directly from host's > > > > > > > > SMC and forward this value to QEMU Guest. > > > > > > > > > > > > > > > > Usage: > > > > > > > > `-device isa-applesmc,hostosk=on` > > > > > > > > > > > > > > > > Apple licence allows use and run up to two additional copies > > > > > > > > or instances of macOS operating within virtual operating system > > > > > > > > environments on each Apple-branded computer that is already running > > > > > > > > the Apple Software, for purposes of: > > > > > > > > - software development > > > > > > > > - testing during software development > > > > > > > > - using macOS Server > > > > > > > > - personal, non-commercial use > > > > > > > > > > > > > > > > Guest macOS requires AppleSMC with correct OSK. The most legal > > > > > > > > way to pass it to the Guest is to forward the key from host SMC > > > > > > > > without any value exposion. > > > > > > > > > > > > > > > > Based on https://web.archive.org/web/20200103161737/osxbook.com/book/bonus/chapter7/tpmdrmmyth/ > > > > > > > > > > > > > > > > Signed-off-by: Vladislav Yaroshchuk > > > > > > > > @@ -331,6 +464,25 @@ static void applesmc_isa_realize(DeviceState *dev, Error **errp) > > > > > > > > isa_register_ioport(&s->parent_obj, &s->io_err, > > > > > > > > s->iobase + APPLESMC_ERR_PORT); > > > > > > > > + if (s->hostosk_flag) { > > > > > > > > + /* > > > > > > > > + * Property 'hostosk' has higher priority than 'osk' > > > > > > > > + * and shadows it. > > > > > > > > + * Free user-provided 'osk' property value > > > > > > > > + */ > > > > > > > > + if (s->osk) { > > > > > > > > + warn_report("isa-applesmc.osk is shadowed " > > > > > > > > + "by isa-applesmc.hostosk"); > > > > > > > > + g_free(s->osk); > > > > > > > > + } > > > > > > > > + > > > > > > > > + if (!applesmc_read_host_osk(&s->osk, &err)) { > > > > > > > > + /* On host OSK retrieval error report a warning */ > > > > > > > > + error_report_err(err); > > > > > > > > + s->osk = default_osk; > > > > > > > > + } > > > > > > > > + } > > > > > > > This part is yucky. A few things: > > > > > > > > > > > > > > 1) QEMU in general does not fail user requested operations silently. If the > > > > > > > user explicitly asked to read the host OSK and we couldn't, it must > > > > > > > propagate that error. > > > > > > > 2) In tandem to the above, I think the only consistent CX is to make both > > > > > > > options mutually exclusive. The easiest way to achieve that IMHO would be to > > > > > > > overload the "osk" property. If it is "host", then use the host one. > > > > > > > 3) Should we make "osk"="host" the default on macOS as well then? Of course, > > > > > > > that one should *not* fail hard when it can't read the key, because it's an > > > > > > > implicit request rather than an explicit one. > > > > > > The problem with using a magic string value for the existing "osk" > > > > > > parameter is that this is not introspectable by management apps. > > > > > What introspectability would you like to have? > > > > Essentially to answer the question > > > > > > > > "Does this QEMU support OSK passthrough from the host" > > > > > > > > Mgmt apps like libvirt introspect using various query-XXX QMP commands. > > > > For devices, the typical approach is to ask for the list of properties > > > > the device supports. If we're just accepting a new magic value on an > > > > existing property there is no way to query for existance of that feature. > > > > If we add a "host-osk=bool" parameter introspectability is trivially > > > > satisfied. > > > > > > Ok, the only flow that remains sensible in that case to me sounds like the > > > following: > > Just need an extra check upfront: > > > > if (s->osk && s->use_hoist_osk) > > error_setg(errp, ...) > > else > > > if (s->osk) { > > >     /* Use osk */ > > This should fail hard if the provided value is the wrong length - currently > > it falls back with a warning IIUC. > > > > > } else if (s->use_host_osk) { > > >     /* Use host OSK. Fail hard if we can't find it */ > > > } else if (can_use_host_osk) { > > >     /* See if we can extract the key from the host. If not, fall back to old > > > behavior */ > > > } else { > > >     /* Old fallback behavior */ > > Was this old fallback behaviour actually useful ? IIUC it means it is using > > > > > > static char default_osk[64] = "This is a dummy key. Enter the real key " > > "using the -osk parameter"; > > > > which obviously isn't a valid key that will work with any gust OS that > > cares. I guess it at least let QEMU startup, but any the guest OS that > > checks the key will be unhappy. > > > > If if don't think default_osk is actually useful, then we could simplify > > further to > > > > if (s->osk && s->use_host_osk) { > > error_setg(errp, ...) > > } else if (s->osk) { > > /* Use osk. Fail hard if invalid (ie wrong length) */ > > } else if (s->use_host_osk) { > > /* Use host OSK. Fail hard if we can't find it */ > > } else { > > /* try to use host OSK, fail hard if we can't find it or non-OS-X build */ > > } > > > In the example above, use_host_osk=on and use_host_osk=off yield the exact > same behavior, so we don't need the switch, no? Hmm, I forgot about machine type back compat. From a strict pov, if we change the default it should only be for the 6.2.0 machine type, with old machines keeping the current 'default_osk' behaviour. IOW, for 6.2.0 machine use_host_osk=on as default, and for < 6.2.0, use_host_osk=off as default . 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 :|