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=-17.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 E31F1C433DB for ; Fri, 5 Feb 2021 03:29:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 83BBF64FBD for ; Fri, 5 Feb 2021 03:29:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229989AbhBED3O (ORCPT ); Thu, 4 Feb 2021 22:29:14 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:37366 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229579AbhBED3O (ORCPT ); Thu, 4 Feb 2021 22:29:14 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612495667; 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=j6n+ZLbkq+mLCc6aBqP6EMe2QS0ih77l0I/R5zi2Q/k=; b=LfdOAVLyXLfWPbqHY6Ghg+KmAczp7R47J/NHlGH34JhiUCT9SCVcdU8eZUmGZdx6rl0FAz Nzoy1nH8HlvDOCMzwD7jr1d3BMKEdIfX9miw1n+NJqgrM8uy8MBxGNZB1J+knEATTZ/UqC PU1pIiqBannsa1VLX/X1CGU5g6z3WIY= 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-521-GXHq2iLTMEGLcKpW42pIgQ-1; Thu, 04 Feb 2021 22:27:45 -0500 X-MC-Unique: GXHq2iLTMEGLcKpW42pIgQ-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 171DE195D560; Fri, 5 Feb 2021 03:27:44 +0000 (UTC) Received: from [10.72.12.112] (ovpn-12-112.pek2.redhat.com [10.72.12.112]) by smtp.corp.redhat.com (Postfix) with ESMTP id 90BAA60937; Fri, 5 Feb 2021 03:27:33 +0000 (UTC) Subject: Re: [PATCH v3 09/13] vhost/vdpa: remove vhost_vdpa_config_validate() To: Stefano Garzarella , virtualization@lists.linux-foundation.org Cc: Xie Yongji , kvm@vger.kernel.org, Laurent Vivier , Stefan Hajnoczi , Max Gurtovoy , linux-kernel@vger.kernel.org, "Michael S. Tsirkin" References: <20210204172230.85853-1-sgarzare@redhat.com> <20210204172230.85853-10-sgarzare@redhat.com> From: Jason Wang Message-ID: <6919d2d4-cc8e-2b67-2385-35803de5e38b@redhat.com> Date: Fri, 5 Feb 2021 11:27:32 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210204172230.85853-10-sgarzare@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/2/5 上午1:22, Stefano Garzarella wrote: > get_config() and set_config() callbacks in the 'struct vdpa_config_ops' > usually already validated the inputs. Also now they can return an error, > so we don't need to validate them here anymore. > > Let's use the return value of these callbacks and return it in case of > error in vhost_vdpa_get_config() and vhost_vdpa_set_config(). > > Originally-by: Xie Yongji > Signed-off-by: Stefano Garzarella > --- > drivers/vhost/vdpa.c | 41 +++++++++++++---------------------------- > 1 file changed, 13 insertions(+), 28 deletions(-) > > diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c > index ef688c8c0e0e..d61e779000a8 100644 > --- a/drivers/vhost/vdpa.c > +++ b/drivers/vhost/vdpa.c > @@ -185,51 +185,35 @@ static long vhost_vdpa_set_status(struct vhost_vdpa *v, u8 __user *statusp) > return 0; > } > > -static int vhost_vdpa_config_validate(struct vhost_vdpa *v, > - struct vhost_vdpa_config *c) > -{ > - long size = 0; > - > - switch (v->virtio_id) { > - case VIRTIO_ID_NET: > - size = sizeof(struct virtio_net_config); > - break; > - } > - > - if (c->len == 0) > - return -EINVAL; > - > - if (c->len > size - c->off) > - return -E2BIG; > - > - return 0; > -} > - > static long vhost_vdpa_get_config(struct vhost_vdpa *v, > struct vhost_vdpa_config __user *c) > { > struct vdpa_device *vdpa = v->vdpa; > struct vhost_vdpa_config config; > unsigned long size = offsetof(struct vhost_vdpa_config, buf); > + long ret; > u8 *buf; > > if (copy_from_user(&config, c, size)) > return -EFAULT; > - if (vhost_vdpa_config_validate(v, &config)) > + if (config.len == 0) > return -EINVAL; > buf = kvzalloc(config.len, GFP_KERNEL); Then it means usersapce can allocate a very large memory. Rethink about this, we should limit the size here (e.g PAGE_SIZE) or fetch the config size first (either through a config ops as you suggested or a variable in the vdpa device that is initialized during device creation). Thanks > if (!buf) > return -ENOMEM; > > - vdpa_get_config(vdpa, config.off, buf, config.len); > + ret = vdpa_get_config(vdpa, config.off, buf, config.len); > + if (ret) > + goto out; > > if (copy_to_user(c->buf, buf, config.len)) { > - kvfree(buf); > - return -EFAULT; > + ret = -EFAULT; > + goto out; > } > > +out: > kvfree(buf); > - return 0; > + return ret; > } > > static long vhost_vdpa_set_config(struct vhost_vdpa *v, > @@ -239,21 +223,22 @@ static long vhost_vdpa_set_config(struct vhost_vdpa *v, > const struct vdpa_config_ops *ops = vdpa->config; > struct vhost_vdpa_config config; > unsigned long size = offsetof(struct vhost_vdpa_config, buf); > + long ret; > u8 *buf; > > if (copy_from_user(&config, c, size)) > return -EFAULT; > - if (vhost_vdpa_config_validate(v, &config)) > + if (config.len == 0) > return -EINVAL; > > buf = vmemdup_user(c->buf, config.len); > if (IS_ERR(buf)) > return PTR_ERR(buf); > > - ops->set_config(vdpa, config.off, buf, config.len); > + ret = ops->set_config(vdpa, config.off, buf, config.len); > > kvfree(buf); > - return 0; > + return ret; > } > > static long vhost_vdpa_get_features(struct vhost_vdpa *v, u64 __user *featurep)