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=-6.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 305D6C07E85 for ; Tue, 11 Dec 2018 15:51:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EAC9820880 for ; Tue, 11 Dec 2018 15:50:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1544543460; bh=V06aAWoFIjpprFabkx1EE5pHz7E4Zh9YQv9qC78QM60=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=k/BUzF+IB3d07Bt1GrtMNtdWBzpNAbm7zDHAcCnG2I4nlDErsk2sju8nM7xI2oOhv QYDx1u59DNOJwjxjOR3huEotyzH/BYJ0PgT8lmNTbfnFb7EwOyuhkwIv+t/n4JxBvE WbtO23yhriRds95J6Polwl3kzX91pWFmFheifS+g= DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EAC9820880 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729402AbeLKPu6 (ORCPT ); Tue, 11 Dec 2018 10:50:58 -0500 Received: from mail.kernel.org ([198.145.29.99]:39530 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729384AbeLKPuy (ORCPT ); Tue, 11 Dec 2018 10:50:54 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A21192146E; Tue, 11 Dec 2018 15:50:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1544543454; bh=V06aAWoFIjpprFabkx1EE5pHz7E4Zh9YQv9qC78QM60=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=G90T/x2vDr6IjtpBtck++r6GceXKjzeveVebB+EW43GQgqTOA4lwPewXIWLyxkTaJ buPeQWJqpwUI30eLBBU/I6lImdOuS/BRIZ6BJB5OLhVRa5/QaKchRAp0EOJbapImCr 9uPCZznkom2iDZJMDhvqesc57TpP9uy+YOxB2guI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Halil Pasic , Cornelia Huck , "Michael S. Tsirkin" Subject: [PATCH 4.9 30/51] virtio/s390: avoid race on vcdev->config Date: Tue, 11 Dec 2018 16:41:38 +0100 Message-Id: <20181211151616.597241287@linuxfoundation.org> X-Mailer: git-send-email 2.20.0 In-Reply-To: <20181211151612.328911565@linuxfoundation.org> References: <20181211151612.328911565@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Halil Pasic commit 2448a299ec416a80f699940a86f4a6d9a4f643b1 upstream. Currently we have a race on vcdev->config in virtio_ccw_get_config() and in virtio_ccw_set_config(). This normally does not cause problems, as these are usually infrequent operations. However, for some devices writing to/reading from the config space can be triggered through sysfs attributes. For these, userspace can force the race by increasing the frequency. Signed-off-by: Halil Pasic Cc: stable@vger.kernel.org Message-Id: <20180925121309.58524-2-pasic@linux.ibm.com> Signed-off-by: Cornelia Huck Signed-off-by: Michael S. Tsirkin Signed-off-by: Greg Kroah-Hartman --- drivers/s390/virtio/virtio_ccw.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) --- a/drivers/s390/virtio/virtio_ccw.c +++ b/drivers/s390/virtio/virtio_ccw.c @@ -837,6 +837,7 @@ static void virtio_ccw_get_config(struct int ret; struct ccw1 *ccw; void *config_area; + unsigned long flags; ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL); if (!ccw) @@ -855,11 +856,13 @@ static void virtio_ccw_get_config(struct if (ret) goto out_free; + spin_lock_irqsave(&vcdev->lock, flags); memcpy(vcdev->config, config_area, offset + len); - if (buf) - memcpy(buf, &vcdev->config[offset], len); if (vcdev->config_ready < offset + len) vcdev->config_ready = offset + len; + spin_unlock_irqrestore(&vcdev->lock, flags); + if (buf) + memcpy(buf, config_area + offset, len); out_free: kfree(config_area); @@ -873,6 +876,7 @@ static void virtio_ccw_set_config(struct struct virtio_ccw_device *vcdev = to_vc_device(vdev); struct ccw1 *ccw; void *config_area; + unsigned long flags; ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL); if (!ccw) @@ -885,9 +889,11 @@ static void virtio_ccw_set_config(struct /* Make sure we don't overwrite fields. */ if (vcdev->config_ready < offset) virtio_ccw_get_config(vdev, 0, NULL, offset); + spin_lock_irqsave(&vcdev->lock, flags); memcpy(&vcdev->config[offset], buf, len); /* Write the config area to the host. */ memcpy(config_area, vcdev->config, sizeof(vcdev->config)); + spin_unlock_irqrestore(&vcdev->lock, flags); ccw->cmd_code = CCW_CMD_WRITE_CONF; ccw->flags = 0; ccw->count = offset + len;