From patchwork Mon Mar 4 22:49:23 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Blake X-Patchwork-Id: 224853 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 95B6D2C032E for ; Tue, 5 Mar 2013 09:49:50 +1100 (EST) Received: from localhost ([::1]:53558 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UCeCa-0001fL-Kn for incoming@patchwork.ozlabs.org; Mon, 04 Mar 2013 17:49:48 -0500 Received: from eggs.gnu.org ([208.118.235.92]:49238) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UCeCI-0001fG-Rb for qemu-devel@nongnu.org; Mon, 04 Mar 2013 17:49:32 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UCeCH-0007u1-EY for qemu-devel@nongnu.org; Mon, 04 Mar 2013 17:49:30 -0500 Received: from qmta10.emeryville.ca.mail.comcast.net ([76.96.30.17]:51522) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UCeCH-0007to-5C for qemu-devel@nongnu.org; Mon, 04 Mar 2013 17:49:29 -0500 Received: from omta21.emeryville.ca.mail.comcast.net ([76.96.30.88]) by qmta10.emeryville.ca.mail.comcast.net with comcast id 7XyP1l0021u4NiLAAapTwq; Mon, 04 Mar 2013 22:49:27 +0000 Received: from office.redhat.com ([24.10.251.25]) by omta21.emeryville.ca.mail.comcast.net with comcast id 7apQ1l0010ZdyUg8hapSZo; Mon, 04 Mar 2013 22:49:27 +0000 From: Eric Blake To: libvir-list@redhat.com Date: Mon, 4 Mar 2013 15:49:23 -0700 Message-Id: <1362437363-27570-1-git-send-email-eblake@redhat.com> X-Mailer: git-send-email 1.8.1.4 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=comcast.net; s=q20121106; t=1362437367; bh=kzvcmIzlDS9RDomxzD1/Ojbrd8N2elqMfvTDvt+tN4E=; h=Received:Received:From:To:Subject:Date:Message-Id; b=pMRlbC1EtqzbAuO8Wb22KCi4BvqtlJXzkGA5XNjrJS9WkTiPeP87/rN/VYGFNBN0C IwcAS+nUe/BtZSRaxYiZjjvu+NfKl95uefUxB1wLS6w2Cww+l7UZULOLV46kLbQZll r/jIb1muQn1zPz5PIUIHdClZrCQ0Y9xrsDkFVVAjniA2Mb2c4e/xOTEex2toJWJnSL IZtOuA/QrJhaOQSTCH3VPhOr3UQZnjjnWOWp7B6VNwQHgdwO5Q+wJ5T9tHZ1H1jUIQ X2Ip9XFq5g8f+UIyyxVuGDc5W4dkzKUiLXa5O4GXScQlv0shOzVQ9bXjw/C0z0blPj 4gZ0cfC/9YQHw== X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 76.96.30.17 Cc: pbonzini@redhat.com, qemu-devel@nongnu.org, anthony@codemonkey.ws Subject: [Qemu-devel] [PATCH] rng: restrict passthrough names to known-good files X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org There is some controversy[1] on the qemu list on whether qemu should have ever allowed arbitrary file name passthrough, or whether it should be restricted to JUST /dev/random and /dev/hwrng. It is always easier to add support for additional filenames than it is to remove support for something once released, so this patch restricts libvirt 1.0.3 (where the virtio-random backend was first supported) to just the two uncontroversial names, letting us defer to a later date any decision on whether supporting arbitrary files makes sense. Additionally, since qemu 1.4 does NOT support /dev/fdset/nnn fd passthrough for the backend, limiting to just two known names means that we don't get tempted to try fd passthrough where it won't work. [1]https://lists.gnu.org/archive/html/qemu-devel/2013-03/threads.html#00023 * src/conf/domain_conf.c (virDomainRNGDefParseXML): Only allow /dev/random and /dev/hwrng. * docs/schemas/domaincommon.rng: Flag invalid files. * docs/formatdomain.html.in (elementsRng): Document this. * tests/qemuxml2argvdata/qemuxml2argv-virtio-rng-random.args: Update test to match. * tests/qemuxml2argvdata/qemuxml2argv-virtio-rng-random.xml: Likewise. Acked-by: Anthony Liguori --- This needs to be acked before libvirt 1.0.3; otherwise we are stuck supporting arbitrary name passthrough. docs/formatdomain.html.in | 3 ++- docs/schemas/domaincommon.rng | 5 ++++- src/conf/domain_conf.c | 7 +++++++ tests/qemuxml2argvdata/qemuxml2argv-virtio-rng-random.args | 2 +- tests/qemuxml2argvdata/qemuxml2argv-virtio-rng-random.xml | 2 +- 5 files changed, 15 insertions(+), 4 deletions(-) diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in index 1835b39..4cafc92 100644 --- a/docs/formatdomain.html.in +++ b/docs/formatdomain.html.in @@ -4310,7 +4310,8 @@ qemu-kvm -net nic,model=? /dev/null model attribute. Supported source models are:

    -
  • 'random' — /dev/random (default) or similar device as source
    • +
  • 'random' — /dev/random (default) or /dev/hwrng + device as source (for now, no other sources are permitted)
  • 'egd' — a EGD protocol backend
diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng index e7231cc..4b60885 100644 --- a/docs/schemas/domaincommon.rng +++ b/docs/schemas/domaincommon.rng @@ -3511,7 +3511,10 @@ random - + + /dev/random + /dev/hwrng + diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c index 995cf0c..9c96cf1 100644 --- a/src/conf/domain_conf.c +++ b/src/conf/domain_conf.c @@ -7423,6 +7423,13 @@ virDomainRNGDefParseXML(const xmlNodePtr node, switch ((enum virDomainRNGBackend) def->backend) { case VIR_DOMAIN_RNG_BACKEND_RANDOM: def->source.file = virXPathString("string(./backend)", ctxt); + if (STRNEQ(def->source.file, "/dev/random") && + STRNEQ(def->source.file, "/dev/hwrng")) { + virReportError(VIR_ERR_XML_ERROR, + _("file '%s' is not a supported random source"), + def->source.file); + goto error; + } break; case VIR_DOMAIN_RNG_BACKEND_EGD: diff --git a/tests/qemuxml2argvdata/qemuxml2argv-virtio-rng-random.args b/tests/qemuxml2argvdata/qemuxml2argv-virtio-rng-random.args index ad27132..7ab9dbc 100644 --- a/tests/qemuxml2argvdata/qemuxml2argv-virtio-rng-random.args +++ b/tests/qemuxml2argvdata/qemuxml2argv-virtio-rng-random.args @@ -2,5 +2,5 @@ LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test /usr/bin/qemu \ -S -M pc -m 214 -smp 1 -nographic -nodefaults \ -monitor unix:/tmp/test-monitor,server,nowait -no-acpi -boot c -usb \ -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3 \ --object 'rng-random,id=rng0,filename=/test/ph - /test/ph<ile + /dev/hwrng