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=-13.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 E09B6C2B9F4 for ; Tue, 22 Jun 2021 11:50:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C38056135F for ; Tue, 22 Jun 2021 11:50:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230327AbhFVLwS (ORCPT ); Tue, 22 Jun 2021 07:52:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36448 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230071AbhFVLwS (ORCPT ); Tue, 22 Jun 2021 07:52:18 -0400 Received: from mail-ej1-x629.google.com (mail-ej1-x629.google.com [IPv6:2a00:1450:4864:20::629]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 80D94C061756 for ; Tue, 22 Jun 2021 04:50:02 -0700 (PDT) Received: by mail-ej1-x629.google.com with SMTP id hz1so11517999ejc.1 for ; Tue, 22 Jun 2021 04:50:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=sbU3A+j/FG5iAg91a8f8bwvtnCy0uA/d+gF6dETaSVg=; b=d0zYt/LlWEAZcBW88+Jx42WFcf1LsNbpablBwlFiU1nxsqTnFFRdy2aPFqUAqS1806 9w3h2Qg9YTkgjCSnI0bWqYlPVvDVYkVAf0PvO58ZGpN1FUhcVjihZ1PWC7QOeo9SuKN9 oBOj+AwNMCVZzWIm7wWi1hD7GkH7nsBK+icabGnVs2b4MBGYT3odKcAXaprzY7DeZ6zB LHLHCdzlePFKqYIm/nJT7XGXuLE1pwr1WauuKSegdUek4FJxh0VRdaQnrWo47uvbcNsG FKPJKTiIFSYyHdDdfZQQH7vpwEQS0aaxnR9X8+dbDUPtqhdvKEaZJyTq1jQ+fx2sg81J AWcg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=sbU3A+j/FG5iAg91a8f8bwvtnCy0uA/d+gF6dETaSVg=; b=ZQZyj4IJ7Sk6jpSQL/qaqZ0E29/Pa8qJXy5pSebQTVMpNZjzBNtDwPRDmNbPUNW9vE XZ8TP62j6/au1A6p7xt2uVvoR4l4qEx8RhrDYovufjb+rLmqTNHdNkS0TccjbOglOYJq G+t/Prect720I7VSY03XS7NpJ3BirEAEs95UFRCr2EaR52kn8awBG01jH+lCnTmfnzM/ OYAnLmUtJ6jhF4MFFA0HK0QPIauCazwg2d7bnbpf4iZJySodl4ZwGaD+SRmUPH0TU3J4 pB/Lskjl7EMS5/KNwUujnyXyVRw3UPSf4jC2T2WiRcCBpYk+osYpCMWYQ2G9+YSLe12P AvsA== X-Gm-Message-State: AOAM531ZBhwPjS1YmmACHT4ZHQC1QEi9E1WHu/sd5wKaAI4r5qnYiKiZ WPvu+zNy47IXg750r1RrDWJmC6FymU/cxSRkARk2 X-Google-Smtp-Source: ABdhPJwjJhnt6HHLPJdVrIzl9bkjRQKXLtyVV33ecWzRUTc1f9JbUSH4QFMVDYoFpXOD2cZMBa2QJMgzFRPRQCo/xSI= X-Received: by 2002:a17:906:c211:: with SMTP id d17mr3545896ejz.247.1624362601096; Tue, 22 Jun 2021 04:50:01 -0700 (PDT) MIME-Version: 1.0 References: <20210617051004.146-1-xieyongji@bytedance.com> In-Reply-To: From: Yongji Xie Date: Tue, 22 Jun 2021 19:49:50 +0800 Message-ID: Subject: Re: Re: [PATCH v3] virtio-blk: Add validation for block size in config space To: Stefan Hajnoczi Cc: "Michael S. Tsirkin" , Jason Wang , Jens Axboe , virtualization , linux-block@vger.kernel.org, linux-kernel Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Tue, Jun 22, 2021 at 6:11 PM Stefan Hajnoczi wrote: > > On Thu, Jun 17, 2021 at 01:10:04PM +0800, Xie Yongji wrote: > > This ensures that we will not use an invalid block size > > in config space (might come from an untrusted device). > > > > Signed-off-by: Xie Yongji > > --- > > drivers/block/virtio_blk.c | 29 +++++++++++++++++++++++------ > > 1 file changed, 23 insertions(+), 6 deletions(-) > > > > diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c > > index b9fa3ef5b57c..bbdae989f1ea 100644 > > --- a/drivers/block/virtio_blk.c > > +++ b/drivers/block/virtio_blk.c > > @@ -696,6 +696,28 @@ static const struct blk_mq_ops virtio_mq_ops = { > > static unsigned int virtblk_queue_depth; > > module_param_named(queue_depth, virtblk_queue_depth, uint, 0444); > > > > +static int virtblk_validate(struct virtio_device *vdev) > > +{ > > + u32 blk_size; > > + > > + if (!vdev->config->get) { > > + dev_err(&vdev->dev, "%s failure: config access disabled\n", > > + __func__); > > + return -EINVAL; > > + } > > + > > + if (!virtio_has_feature(vdev, VIRTIO_BLK_F_BLK_SIZE)) > > + return 0; > > + > > + blk_size = virtio_cread32(vdev, > > + offsetof(struct virtio_blk_config, blk_size)); > > + > > + if (blk_size < SECTOR_SIZE || blk_size > PAGE_SIZE) > > + __virtio_clear_bit(vdev, VIRTIO_BLK_F_BLK_SIZE); > > + > > + return 0; > > +} > > I saw Michael asked for .validate() in v2. I would prefer to keep > everything in virtblk_probe() instead of adding .validate() because: > > - There is a race condition that an untrusted device can exploit since > virtblk_probe() fetches the value again. > Good point! I agree that it's better to add the validation in virtblk_probe(). Thanks, Yongji