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=-17.6 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 AC39FC2B9F7 for ; Tue, 25 May 2021 01:31:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 89C6E61401 for ; Tue, 25 May 2021 01:31:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229921AbhEYBdT (ORCPT ); Mon, 24 May 2021 21:33:19 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:49890 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229480AbhEYBdS (ORCPT ); Mon, 24 May 2021 21:33:18 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1621906309; 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=cDdaKbZRoEfpRx7jvBHZ30BNzMElKWImpQ5xMxNgdjo=; b=SfA3m2VzLmYhEUyZxxfZJgSqpCLwYbQlhtL0zK8s3VXYuT1hVgLsL4dPm6IC0VMvBa8v9+ Y2j71aITQ2NALkbDArvlKzFXGpL7dSSm6xLwWEFUVkzj5dMs3OLKUkty7rY/GaqmDPHRQ4 FlePnPmJMupH0dfmOuYehAjBnE8H1pg= Received: from mail-pf1-f197.google.com (mail-pf1-f197.google.com [209.85.210.197]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-462-W39gDJscN2SmUiR_jVIrlw-1; Mon, 24 May 2021 21:31:47 -0400 X-MC-Unique: W39gDJscN2SmUiR_jVIrlw-1 Received: by mail-pf1-f197.google.com with SMTP id s5-20020aa78d450000b02902ace63a7e93so19376782pfe.8 for ; Mon, 24 May 2021 18:31:47 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding :content-language; bh=cDdaKbZRoEfpRx7jvBHZ30BNzMElKWImpQ5xMxNgdjo=; b=mTbIiV8uKYa90ETMekqgq8wioqXm5xLydnjY/AohgWyKfRsE3eLmdaV+kNqN+1B09r PX7R2L6C6K+LGf/iyPCa74NUEufcJhXZOdT6yKh4NEaLUUSk2vgQdM/R7fwU7itzsvF7 FkBI/2OTyTjw91/bEQec6PDmRDxS9S925GR0d0d9Lfq6qbAi+oH5BabdZ2NejA5WYo2h qDlyxRop9Ftf6eReiIYMPrTxOSiR6DCWoX54o+SNrMYB798C4XdikuXvhVZnQiqWv18W nREnz4zSOCencmQu5snAlEed9NL8byhY50uR+exC92yVXvuj+pwqIRKDmXppOUBP/Re7 TJ/A== X-Gm-Message-State: AOAM5329HLo04waSIhJWXqM1tsNtDZNt9+Fe9uiHuQRGKA6f5UN9UBwe QMCrro6+Jx5izV2ylf1MYLlIUiTtMu4fi4+aPWus1ZULXVRd99QMtlpgvh6uQIMfrgLGgyspTtE wOKHuuuoqNfSJpjgk5Ccqje4GFoMh1Z7ecPt7xgO4oqdyQ++zM77fuyMK0NRyIH4igSKPpwAA1Z BA X-Received: by 2002:a17:90b:1b4c:: with SMTP id nv12mr27605024pjb.55.1621906305717; Mon, 24 May 2021 18:31:45 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzaC2zarJrBIyP6vFqRiVxlMn0IGK6h9Za0XGOhe7G4c1aNDy85YgjxCOlh7xcd0n+tZ+3O1A== X-Received: by 2002:a17:90b:1b4c:: with SMTP id nv12mr27604972pjb.55.1621906305157; Mon, 24 May 2021 18:31:45 -0700 (PDT) Received: from wangxiaodeMacBook-Air.local ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id f80sm11774204pfa.160.2021.05.24.18.31.39 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 24 May 2021 18:31:44 -0700 (PDT) Subject: Re: [RFC PATCH 17/17] virtio_ring: Add validation for used length To: "Michael S. Tsirkin" , Xie Yongji Cc: stefanha@redhat.com, amit@kernel.org, arei.gonglei@huawei.com, airlied@linux.ie, kraxel@redhat.com, dan.j.williams@intel.com, johannes@sipsolutions.net, ohad@wizery.com, bjorn.andersson@linaro.org, david@redhat.com, vgoyal@redhat.com, miklos@szeredi.hu, sgarzare@redhat.com, virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org References: <20210517090836.533-1-xieyongji@bytedance.com> <20210517090836.533-18-xieyongji@bytedance.com> <20210517193641-mutt-send-email-mst@kernel.org> From: Jason Wang Message-ID: <3cda643a-1363-65bf-be84-f6dea6714477@redhat.com> Date: Tue, 25 May 2021 09:31:33 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.10.2 MIME-Version: 1.0 In-Reply-To: <20210517193641-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=gbk; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ÔÚ 2021/5/18 ÉÏÎç7:39, Michael S. Tsirkin дµÀ: > On Mon, May 17, 2021 at 05:08:36PM +0800, Xie Yongji wrote: >> This adds validation for used length (might come >> from an untrusted device) when it will be used by >> virtio device driver. >> >> Signed-off-by: Xie Yongji >> --- >> drivers/virtio/virtio_ring.c | 22 +++++++++++++++++++--- >> 1 file changed, 19 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c >> index d999a1d6d271..7d4845d06f21 100644 >> --- a/drivers/virtio/virtio_ring.c >> +++ b/drivers/virtio/virtio_ring.c >> @@ -68,11 +68,13 @@ >> struct vring_desc_state_split { >> void *data; /* Data for callback. */ >> struct vring_desc *indir_desc; /* Indirect descriptor, if any. */ >> + u32 in_len; /* Total length of writable buffer */ >> }; >> >> struct vring_desc_state_packed { >> void *data; /* Data for callback. */ >> struct vring_packed_desc *indir_desc; /* Indirect descriptor, if any. */ >> + u32 in_len; /* Total length of writable buffer */ >> u16 num; /* Descriptor list length. */ >> u16 last; /* The last desc state in a list. */ >> }; > > Hmm for packed it's aligned to 64 bit anyway, so we are not making it > any worse. But for split this pushes struct size up by 1/3 increasing > cache pressure. We can eliminate this by validating through virtio device driver instead of virtio core. E.g for virtio-net we know the rx buffer size so there's no need to store in twice in the core. Thanks > > >> @@ -486,7 +488,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, >> struct vring_virtqueue *vq = to_vvq(_vq); >> struct scatterlist *sg; >> struct vring_desc *desc; >> - unsigned int i, n, avail, descs_used, prev, err_idx; >> + unsigned int i, n, avail, descs_used, prev, err_idx, in_len = 0; >> int head; >> bool indirect; >> >> @@ -570,6 +572,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, >> VRING_DESC_F_NEXT | >> VRING_DESC_F_WRITE, >> indirect); >> + in_len += sg->length; >> } >> } >> /* Last one doesn't continue. */ >> @@ -604,6 +607,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, >> >> /* Store token and indirect buffer state. */ >> vq->split.desc_state[head].data = data; >> + vq->split.desc_state[head].in_len = in_len; >> if (indirect) >> vq->split.desc_state[head].indir_desc = desc; >> else >> @@ -784,6 +788,10 @@ static void *virtqueue_get_buf_ctx_split(struct virtqueue *_vq, >> BAD_RING(vq, "id %u is not a head!\n", i); >> return NULL; >> } >> + if (unlikely(len && vq->split.desc_state[i].in_len < *len)) { >> + BAD_RING(vq, "id %u has invalid length: %u!\n", i, *len); >> + return NULL; >> + } >> >> /* detach_buf_split clears data, so grab it now. */ >> ret = vq->split.desc_state[i].data; >> @@ -1059,7 +1067,7 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq, >> { >> struct vring_packed_desc *desc; >> struct scatterlist *sg; >> - unsigned int i, n, err_idx; >> + unsigned int i, n, err_idx, in_len = 0; >> u16 head, id; >> dma_addr_t addr; >> >> @@ -1084,6 +1092,7 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq, >> if (vring_mapping_error(vq, addr)) >> goto unmap_release; >> >> + in_len += (n < out_sgs) ? 0 : sg->length; >> desc[i].flags = cpu_to_le16(n < out_sgs ? >> 0 : VRING_DESC_F_WRITE); >> desc[i].addr = cpu_to_le64(addr); >> @@ -1141,6 +1150,7 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq, >> vq->packed.desc_state[id].data = data; >> vq->packed.desc_state[id].indir_desc = desc; >> vq->packed.desc_state[id].last = id; >> + vq->packed.desc_state[id].in_len = in_len; >> >> vq->num_added += 1; >> >> @@ -1173,7 +1183,7 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq, >> struct vring_virtqueue *vq = to_vvq(_vq); >> struct vring_packed_desc *desc; >> struct scatterlist *sg; >> - unsigned int i, n, c, descs_used, err_idx; >> + unsigned int i, n, c, descs_used, err_idx, in_len = 0; >> __le16 head_flags, flags; >> u16 head, id, prev, curr, avail_used_flags; >> >> @@ -1223,6 +1233,7 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq, >> if (vring_mapping_error(vq, addr)) >> goto unmap_release; >> >> + in_len += (n < out_sgs) ? 0 : sg->length; >> flags = cpu_to_le16(vq->packed.avail_used_flags | >> (++c == total_sg ? 0 : VRING_DESC_F_NEXT) | >> (n < out_sgs ? 0 : VRING_DESC_F_WRITE)); >> @@ -1268,6 +1279,7 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq, >> vq->packed.desc_state[id].data = data; >> vq->packed.desc_state[id].indir_desc = ctx; >> vq->packed.desc_state[id].last = prev; >> + vq->packed.desc_state[id].in_len = in_len; >> >> /* >> * A driver MUST NOT make the first descriptor in the list >> @@ -1456,6 +1468,10 @@ static void *virtqueue_get_buf_ctx_packed(struct virtqueue *_vq, >> BAD_RING(vq, "id %u is not a head!\n", id); >> return NULL; >> } >> + if (unlikely(len && vq->packed.desc_state[id].in_len < *len)) { >> + BAD_RING(vq, "id %u has invalid length: %u!\n", id, *len); >> + return NULL; >> + } >> >> /* detach_buf_packed clears data, so grab it now. */ >> ret = vq->packed.desc_state[id].data; >> -- >> 2.11.0