From patchwork Tue Feb 25 05:59:19 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Gerd Hoffmann X-Patchwork-Id: 11402539 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 68DAD138D for ; Tue, 25 Feb 2020 06:02:06 +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 3EDFE20732 for ; Tue, 25 Feb 2020 06:02:06 +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="cDpgg97k" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3EDFE20732 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+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:49388 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j6TID-0005dV-Cl for patchwork-qemu-devel@patchwork.kernel.org; Tue, 25 Feb 2020 01:02:05 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:33484) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j6TGP-0003zZ-1c for qemu-devel@nongnu.org; Tue, 25 Feb 2020 01:00:13 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1j6TGN-0000VS-TU for qemu-devel@nongnu.org; Tue, 25 Feb 2020 01:00:12 -0500 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:51333 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1j6TGN-0000Tv-Pm for qemu-devel@nongnu.org; Tue, 25 Feb 2020 01:00:11 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1582610411; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=xajBEGYWjfHpz6efNBjFQNX4VpyfGfJO9a0s/56wfzA=; b=cDpgg97kKQdtL2dPhz5cV2xS7KWho+Xa5ojy/N44/Pc6EKjdLCpKO07ykRWRDYNAzUr94K jeQlZXQKOnftejEZH7uJCY5DHNc3gg5CC7YWUY+ECwVQUDm8xfRdcbFhaXti/atbmkLBMJ ivmIhx19CEAW+KSMAq8eWdJbn8tqfYY= 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-415-EQatYADTN9CjcWr7u5sw7g-1; Tue, 25 Feb 2020 00:59:31 -0500 X-MC-Unique: EQatYADTN9CjcWr7u5sw7g-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4B491800D50; Tue, 25 Feb 2020 05:59:30 +0000 (UTC) Received: from sirius.home.kraxel.org (ovpn-116-87.ams2.redhat.com [10.36.116.87]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9183E5D9CD; Tue, 25 Feb 2020 05:59:21 +0000 (UTC) Received: by sirius.home.kraxel.org (Postfix, from userid 1000) id 845FB9D23; Tue, 25 Feb 2020 06:59:20 +0100 (CET) From: Gerd Hoffmann To: qemu-devel@nongnu.org Subject: [PATCH 1/2] qxl: map rom r/o Date: Tue, 25 Feb 2020 06:59:19 +0100 Message-Id: <20200225055920.17261-2-kraxel@redhat.com> In-Reply-To: <20200225055920.17261-1-kraxel@redhat.com> References: <20200225055920.17261-1-kraxel@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.81 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: sstabellini@kernel.org, pmatouse@redhat.com, "Michael S. Tsirkin" , mdroth@linux.vnet.ibm.com, ppandit@redhat.com, Gerd Hoffmann , Paolo Bonzini Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" Map qxl rom read-only into the guest, so the guest can't tamper with the content. qxl has a shadow copy of the rom to deal with that, but the shadow doesn't cover the mode list. A privilidged user in the guest can manipulate the mode list and that to trick qemu into oob reads, leading to a DoS via segfault if that read access happens to hit unmapped memory. Signed-off-by: Gerd Hoffmann Reviewed-by: Philippe Mathieu-Daudé --- hw/display/qxl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/hw/display/qxl.c b/hw/display/qxl.c index 21a43a1d5ec2..227da69a50d9 100644 --- a/hw/display/qxl.c +++ b/hw/display/qxl.c @@ -2136,7 +2136,7 @@ static void qxl_realize_common(PCIQXLDevice *qxl, Error **errp) pci_set_byte(&config[PCI_INTERRUPT_PIN], 1); qxl->rom_size = qxl_rom_size(); - memory_region_init_ram(&qxl->rom_bar, OBJECT(qxl), "qxl.vrom", + memory_region_init_rom(&qxl->rom_bar, OBJECT(qxl), "qxl.vrom", qxl->rom_size, &error_fatal); init_qxl_rom(qxl); init_qxl_ram(qxl);