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 X-Spam-Level: X-Spam-Status: No, score=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A9BADC433E0 for ; Fri, 29 May 2020 10:11:08 +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 6A12A2074D for ; Fri, 29 May 2020 10:11:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="h1xicvkk" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6A12A2074D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:55856 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jebyl-00088Z-Io for qemu-devel@archiver.kernel.org; Fri, 29 May 2020 06:11:07 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:54290) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jebxx-0006pl-CE for qemu-devel@nongnu.org; Fri, 29 May 2020 06:10:17 -0400 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:26873 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jebxw-00029m-Ak for qemu-devel@nongnu.org; Fri, 29 May 2020 06:10:17 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1590747015; h=from:from: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=CaeojVsBWiIqjQORqwThWY6fz2VvVR39cgTT44Vmiu4=; b=h1xicvkk4239Os6Zr9o7BeRMh93NE2OCQe8S/Cieb/pjfl/4scjlqB4zVYhm6U1xMDTrAj JIQwKb9vAgbNUhq1l93qzqn+Fnmc5n31/Uo1GMSy4LItR/QgjrSCfqIC/633/9/JRk/OXX xTMI/aonlZM569hx6oJ2bC3uulyNjWY= 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-366-_-UmC0UNN_-xI1DxGNWYOw-1; Fri, 29 May 2020 06:10:13 -0400 X-MC-Unique: _-UmC0UNN_-xI1DxGNWYOw-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 72B681855A08 for ; Fri, 29 May 2020 10:10:12 +0000 (UTC) Received: from lacos-laptop-7.usersys.redhat.com (ovpn-112-152.ams2.redhat.com [10.36.112.152]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3F3E11002389; Fri, 29 May 2020 10:10:08 +0000 (UTC) Subject: Re: [RFC PATCH v7 3/5] softmmu/vl: Allow -fw_cfg 'gen_id' option to use the 'etc/' namespace To: =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= , qemu-devel@nongnu.org References: <20200528173141.17495-1-philmd@redhat.com> <20200528173141.17495-4-philmd@redhat.com> From: Laszlo Ersek Message-ID: <60cf5894-4d3b-9ab7-f6da-d3556217fdeb@redhat.com> Date: Fri, 29 May 2020 12:10:07 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20200528173141.17495-4-philmd@redhat.com> Content-Language: en-US X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=205.139.110.61; envelope-from=lersek@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/29 03:05:19 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] 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_H2=-0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN 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: , Cc: Paolo Bonzini , "=?UTF-8?Q?Daniel_P._Berrang=c3=a9?=" , Gerd Hoffmann Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 05/28/20 19:31, Philippe Mathieu-Daudé wrote: > User-generated fw_cfg keys should be prefixed with "opt/". (1) Please formulate this as follows: 'Names of user-provided fw_cfg items are supposed to start with "opt/".' (Because we're really not "prefixing keys".) > However FW_CFG_DATA_GENERATOR keys are generated by QEMU, (2) s/keys/items/ > so allow the "etc/" namespace in this specific case. > > Signed-off-by: Philippe Mathieu-Daudé > --- > v7: reword commit description and added comment in code > --- > softmmu/vl.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/softmmu/vl.c b/softmmu/vl.c > index cdb1d187ed..d5423eaf2b 100644 > --- a/softmmu/vl.c > +++ b/softmmu/vl.c > @@ -2049,7 +2049,13 @@ static int parse_fw_cfg(void *opaque, QemuOpts *opts, Error **errp) > FW_CFG_MAX_FILE_PATH - 1); > return -1; > } > - if (strncmp(name, "opt/", 4) != 0) { > + if (!nonempty_str(gen_id)) { (3) I think this condition should be inverted. We'd like to suppress the warning when "gen_id" is specified. In that case, nonempty_str(gen_id) returns "true". In other words, please drop the "!" operator. > + /* > + * In this particular case where the content is populated > + * internally, the "etc/" namespace protection is relaxed, > + * so do not emit a warning. > + */ > + } else if (strncmp(name, "opt/", 4) != 0) { > warn_report("externally provided fw_cfg item names " > "should be prefixed with \"opt/\""); > } > (4) I think having this in a separate patch is nice; I agree we should do this. But I'd like to request a small update to "docs/specs/fw_cfg.txt" as well, in the same patch. Namely, where the document says: """ Use of names not beginning with "opt/" is potentially dangerous and entirely unsupported. QEMU will warn if you try. """ Please append: """ Use of names not beginning with "opt/" is tolerated with 'gen_id' (that is, the warning is suppressed), but you must know exactly what you're doing. """ Because this highlights that the user (or the management tool) *actively participates* in connecting the content generated by QEMU with the fw_cfg filename expected by the firmware. With (1) through (4) fixed: Reviewed-by: Laszlo Ersek Thanks, Laszlo