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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2167FC433EF for ; Tue, 2 Nov 2021 03:54:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E5CB260FC2 for ; Tue, 2 Nov 2021 03:54:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232725AbhKBD5A (ORCPT ); Mon, 1 Nov 2021 23:57:00 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:42817 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232129AbhKBD45 (ORCPT ); Mon, 1 Nov 2021 23:56:57 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1635825263; 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: in-reply-to:in-reply-to:references:references; bh=CZyyl0TVW5IjSjKmk16FYhpmpNrCsjekrv5/NqsRPmo=; b=MKwGIS4xB5AbsQANkagde5c9EvlQXr2Kp3NsIUa0Q3WHsM+9NGfsMmH5LSbJ0Vy8TyDJ2/ eTdMkvjBOjjWbzejBeLl2VbJXb2qIfn83fNAvYKNv5lsMt+PUknlgXwQH5p7ZoHVi1M6Pr U2T6wQBo1atOlHT3dU6t0VJzP7+GbUQ= Received: from mail-lj1-f198.google.com (mail-lj1-f198.google.com [209.85.208.198]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-94-vdC7O_wLMNuw4WkeotA06g-1; Mon, 01 Nov 2021 23:54:22 -0400 X-MC-Unique: vdC7O_wLMNuw4WkeotA06g-1 Received: by mail-lj1-f198.google.com with SMTP id b8-20020a05651c028800b00211cc108922so6937662ljo.15 for ; Mon, 01 Nov 2021 20:54:21 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=CZyyl0TVW5IjSjKmk16FYhpmpNrCsjekrv5/NqsRPmo=; b=MLjQ7gXuDCZaI/Yymoc+fsSIcKw+aHrRXCmtMEdnO08mwObHmtN2t3su0KxxHZnhBs SuZTw+c7hpkhW3lB3TkgXcZ987bb0qy2xIuatcE2FY9c/0xbOmCz7FsEXCWpDGF2fJRB uSmuxV3ljU2li+9nWL3N9AhClMXVzL3beWCREUcesb77K2X1wfkMqYvGqsR0LMHlnhgf aBbVPm+pqAy6UeOnoDxMa1BhjH0REOlb9Db0ML+/BNSBtifJiYuy3GVYrXwrvhX/j7CF DO0DrtP+d/Nui3HPwvGGsdogzLqAYM481NevSNp/61mpPYjeLIjlIClZ+emaC/reG3Kd 1uHA== X-Gm-Message-State: AOAM5308n275MR4rdI8V/wJTSigPg20m/qRKEZrmTLSNBmOZEqIgSkFl dwJ3f6ItBCT+SuZz7qrkw1BU2CIcW/OBQLFBMlSTHHg+S9v8CcQ07j2RnNxs/9mXMEWzd+vv5XZ zKZXZ7KxZmHngLB83NDfdTcsG7hhCdWUP4UY4C+Hy X-Received: by 2002:a05:6512:1291:: with SMTP id u17mr32958874lfs.84.1635825260570; Mon, 01 Nov 2021 20:54:20 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzRIQ+z5bRRGv9yeZAuxUIB+7vDq/QSTl9mFm+K4uBUJvyEW3Z26FBIzcgAayLu+2xhJTS/5htZMl4mL7Lcvfw= X-Received: by 2002:a05:6512:1291:: with SMTP id u17mr32958849lfs.84.1635825260308; Mon, 01 Nov 2021 20:54:20 -0700 (PDT) MIME-Version: 1.0 References: <20211027022107.14357-2-jasowang@redhat.com> <1635823138.4631283-1-xuanzhuo@linux.alibaba.com> In-Reply-To: <1635823138.4631283-1-xuanzhuo@linux.alibaba.com> From: Jason Wang Date: Tue, 2 Nov 2021 11:54:09 +0800 Message-ID: Subject: Re: [PATCH V5 1/4] virtio_ring: validate used buffer length To: Xuan Zhuo Cc: "Hetzelt, Felicitas" , linux-kernel , "kaplan, david" , Konrad Rzeszutek Wilk , mst , virtualization Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 2, 2021 at 11:22 AM Xuan Zhuo wrote: > > On Wed, 27 Oct 2021 10:21:04 +0800, Jason Wang wrote: > > This patch validate the used buffer length provided by the device > > before trying to use it. This is done by record the in buffer length > > in a new field in desc_state structure during virtqueue_add(), then we > > can fail the virtqueue_get_buf() when we find the device is trying to > > give us a used buffer length which is greater than the in buffer > > length. > > > > Since some drivers have already done the validation by themselves, > > this patch tries to makes the core validation optional. For the driver > > that doesn't want the validation, it can set the > > suppress_used_validation to be true (which could be overridden by > > force_used_validation module parameter). To be more efficient, a > > dedicate array is used for storing the validate used length, this > > helps to eliminate the cache stress if validation is done by the > > driver. > > > > Signed-off-by: Jason Wang > > --- > > drivers/virtio/virtio_ring.c | 60 ++++++++++++++++++++++++++++++++++++ > > include/linux/virtio.h | 2 ++ > > 2 files changed, 62 insertions(+) > > > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > > index 4c0ec82cef56..a6e5a3b94337 100644 > > --- a/drivers/virtio/virtio_ring.c > > +++ b/drivers/virtio/virtio_ring.c > > @@ -14,6 +14,9 @@ > > #include > > #include > > > > +static bool force_used_validation = false; > > +module_param(force_used_validation, bool, 0444); > > + > > #ifdef DEBUG > > /* For development, we want to crash whenever the ring is screwed. */ > > #define BAD_RING(_vq, fmt, args...) \ > > @@ -182,6 +185,9 @@ struct vring_virtqueue { > > } packed; > > }; > > > > + /* Per-descriptor in buffer length */ > > + u32 *buflen; > > + > > /* How to notify other side. FIXME: commonalize hcalls! */ > > bool (*notify)(struct virtqueue *vq); > > > > @@ -490,6 +496,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, > > unsigned int i, n, avail, descs_used, prev, err_idx; > > int head; > > bool indirect; > > + u32 buflen = 0; > > > > START_USE(vq); > > > > @@ -571,6 +578,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, > > VRING_DESC_F_NEXT | > > VRING_DESC_F_WRITE, > > indirect); > > + buflen += sg->length; > > } > > } > > /* Last one doesn't continue. */ > > @@ -610,6 +618,10 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, > > else > > vq->split.desc_state[head].indir_desc = ctx; > > > > + /* Store in buffer length if necessary */ > > + if (vq->buflen) > > + vq->buflen[head] = buflen; > > + > > /* Put entry in available array (but don't update avail->idx until they > > * do sync). */ > > avail = vq->split.avail_idx_shadow & (vq->split.vring.num - 1); > > @@ -784,6 +796,11 @@ static void *virtqueue_get_buf_ctx_split(struct virtqueue *_vq, > > BAD_RING(vq, "id %u is not a head!\n", i); > > return NULL; > > } > > + if (vq->buflen && unlikely(*len > vq->buflen[i])) { > > + BAD_RING(vq, "used len %d is larger than in buflen %u\n", > > + *len, vq->buflen[i]); > > + return NULL; > > + } > > > > /* detach_buf_split clears data, so grab it now. */ > > ret = vq->split.desc_state[i].data; > > @@ -1062,6 +1079,7 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq, > > unsigned int i, n, err_idx; > > u16 head, id; > > dma_addr_t addr; > > + u32 buflen = 0; > > > > head = vq->packed.next_avail_idx; > > desc = alloc_indirect_packed(total_sg, gfp); > > @@ -1091,6 +1109,8 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq, > > desc[i].addr = cpu_to_le64(addr); > > desc[i].len = cpu_to_le32(sg->length); > > i++; > > + if (n >= out_sgs) > > + buflen += sg->length; > > } > > } > > > > @@ -1144,6 +1164,10 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq, > > vq->packed.desc_state[id].indir_desc = desc; > > vq->packed.desc_state[id].last = id; > > > > + /* Store in buffer length if necessary */ > > + if (vq->buflen) > > + vq->buflen[id] = buflen; > > + > > vq->num_added += 1; > > > > pr_debug("Added buffer head %i to %p\n", head, vq); > > @@ -1179,6 +1203,7 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq, > > __le16 head_flags, flags; > > u16 head, id, prev, curr, avail_used_flags; > > int err; > > + u32 buflen = 0; > > > > START_USE(vq); > > > > @@ -1258,6 +1283,8 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq, > > 1 << VRING_PACKED_DESC_F_AVAIL | > > 1 << VRING_PACKED_DESC_F_USED; > > } > > + if (n >= out_sgs) > > + buflen += sg->length; > > } > > } > > > > @@ -1277,6 +1304,10 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq, > > vq->packed.desc_state[id].indir_desc = ctx; > > vq->packed.desc_state[id].last = prev; > > > > + /* Store in buffer length if necessary */ > > + if (vq->buflen) > > + vq->buflen[id] = buflen; > > + > > /* > > * A driver MUST NOT make the first descriptor in the list > > * available before all subsequent descriptors comprising > > @@ -1463,6 +1494,11 @@ static void *virtqueue_get_buf_ctx_packed(struct virtqueue *_vq, > > BAD_RING(vq, "id %u is not a head!\n", id); > > return NULL; > > } > > + if (vq->buflen && unlikely(*len > vq->buflen[id])) { > > + BAD_RING(vq, "used len %d is larger than in buflen %u\n", > > + *len, vq->buflen[id]); > > + return NULL; > > + } > > > > /* detach_buf_packed clears data, so grab it now. */ > > ret = vq->packed.desc_state[id].data; > > @@ -1668,6 +1704,7 @@ static struct virtqueue *vring_create_virtqueue_packed( > > struct vring_virtqueue *vq; > > struct vring_packed_desc *ring; > > struct vring_packed_desc_event *driver, *device; > > + struct virtio_driver *drv = drv_to_virtio(vdev->dev.driver); > > dma_addr_t ring_dma_addr, driver_event_dma_addr, device_event_dma_addr; > > size_t ring_size_in_bytes, event_size_in_bytes; > > > > @@ -1757,6 +1794,15 @@ static struct virtqueue *vring_create_virtqueue_packed( > > if (!vq->packed.desc_extra) > > goto err_desc_extra; > > > > + if (!drv->suppress_used_validation || force_used_validation) { > > + vq->buflen = kmalloc_array(num, sizeof(*vq->buflen), > > + GFP_KERNEL); > > + if (!vq->buflen) > > + goto err_buflen; > > The reason for not using "struct vring_desc_state_split/ struct vring_desc_state_split" > is to occupy less memory when turning off this function? Less memory and less cache pressure. Thanks > > Thanks. > > > + } else { > > + vq->buflen = NULL; > > + } > > + > > /* No callback? Tell other side not to bother us. */ > > if (!callback) { > > vq->packed.event_flags_shadow = VRING_PACKED_EVENT_FLAG_DISABLE; > > @@ -1769,6 +1815,8 @@ static struct virtqueue *vring_create_virtqueue_packed( > > spin_unlock(&vdev->vqs_list_lock); > > return &vq->vq; > > > > +err_buflen: > > + kfree(vq->packed.desc_extra); > > err_desc_extra: > > kfree(vq->packed.desc_state); > > err_desc_state: > > @@ -2176,6 +2224,7 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index, > > void (*callback)(struct virtqueue *), > > const char *name) > > { > > + struct virtio_driver *drv = drv_to_virtio(vdev->dev.driver); > > struct vring_virtqueue *vq; > > > > if (virtio_has_feature(vdev, VIRTIO_F_RING_PACKED)) > > @@ -2235,6 +2284,15 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index, > > if (!vq->split.desc_extra) > > goto err_extra; > > > > + if (!drv->suppress_used_validation || force_used_validation) { > > + vq->buflen = kmalloc_array(vring.num, sizeof(*vq->buflen), > > + GFP_KERNEL); > > + if (!vq->buflen) > > + goto err_buflen; > > + } else { > > + vq->buflen = NULL; > > + } > > + > > /* Put everything in free lists. */ > > vq->free_head = 0; > > memset(vq->split.desc_state, 0, vring.num * > > @@ -2245,6 +2303,8 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index, > > spin_unlock(&vdev->vqs_list_lock); > > return &vq->vq; > > > > +err_buflen: > > + kfree(vq->split.desc_extra); > > err_extra: > > kfree(vq->split.desc_state); > > err_state: > > diff --git a/include/linux/virtio.h b/include/linux/virtio.h > > index 41edbc01ffa4..44d0e09da2d9 100644 > > --- a/include/linux/virtio.h > > +++ b/include/linux/virtio.h > > @@ -152,6 +152,7 @@ size_t virtio_max_dma_size(struct virtio_device *vdev); > > * @feature_table_size: number of entries in the feature table array. > > * @feature_table_legacy: same as feature_table but when working in legacy mode. > > * @feature_table_size_legacy: number of entries in feature table legacy array. > > + * @suppress_used_validation: set to not have core validate used length > > * @probe: the function to call when a device is found. Returns 0 or -errno. > > * @scan: optional function to call after successful probe; intended > > * for virtio-scsi to invoke a scan. > > @@ -168,6 +169,7 @@ struct virtio_driver { > > unsigned int feature_table_size; > > const unsigned int *feature_table_legacy; > > unsigned int feature_table_size_legacy; > > + bool suppress_used_validation; > > int (*validate)(struct virtio_device *dev); > > int (*probe)(struct virtio_device *dev); > > void (*scan)(struct virtio_device *dev); > > -- > > 2.25.1 > > > > _______________________________________________ > > Virtualization mailing list > > Virtualization@lists.linux-foundation.org > > https://lists.linuxfoundation.org/mailman/listinfo/virtualization >