Re: [RFC PATCH 00/17] Add validation for used length
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: 2021-05-17 23:40:15
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On Mon, May 17, 2021 at 05:08:19PM +0800, Xie Yongji wrote:
Current virtio device drivers may trust the used length returned in virtqueue_get_buf()/virtqueue_get_buf_ctx(). But the used length might come from an untrusted device when VDUSE[1] is enabled. To protect this case, this series tries to add validation for the used length. Since many legacy devices will also set the used length incorrectly, we did not add the validation unconditionally. Instead, we will do the validation only when the device driver needs the used length. A NULL len passed to virtqueue_get_buf()/virtqueue_get_buf_ctx() will mean the used length is not needed by the device driver.
Can we be more specific? Which drivers have problems when used len is incorrect? Maybe there's an easier way like validating the length in the driver ...
[1] https://lore.kernel.org/kvm/20210331080519.172-1-xieyongji@bytedance.com/ (local) Xie Yongji (17): virtio_ring: Avoid reading unneeded used length virtio-blk: Remove unused used length virtio_console: Remove unused used length crypto: virtio - Remove unused used length drm/virtio: Remove unused used length caif_virtio: Remove unused used length virtio_net: Remove unused used length mac80211_hwsim: Remove unused used length virtio_pmem: Remove unused used length rpmsg: virtio: Remove unused used length virtio_scsi: Remove unused used length virtio_balloon: Remove unused used length virtio_input: Remove unused used length virtio_mem: Remove unused used length virtiofs: Remove unused used length vsock: Remove unused used length virtio_ring: Add validation for used length drivers/block/virtio_blk.c | 3 +-- drivers/char/virtio_console.c | 12 ++++-------- drivers/crypto/virtio/virtio_crypto_algs.c | 6 ++---- drivers/gpu/drm/virtio/virtgpu_vq.c | 3 +-- drivers/net/caif/caif_virtio.c | 3 +-- drivers/net/virtio_net.c | 10 ++++------ drivers/net/wireless/mac80211_hwsim.c | 3 +-- drivers/nvdimm/nd_virtio.c | 3 +-- drivers/rpmsg/virtio_rpmsg_bus.c | 3 +-- drivers/scsi/virtio_scsi.c | 3 +-- drivers/virtio/virtio_balloon.c | 21 ++++++++++----------- drivers/virtio/virtio_input.c | 6 ++---- drivers/virtio/virtio_mem.c | 3 +-- drivers/virtio/virtio_ring.c | 28 +++++++++++++++++++++++----- fs/fuse/virtio_fs.c | 6 ++---- net/vmw_vsock/virtio_transport.c | 3 +-- 16 files changed, 56 insertions(+), 60 deletions(-) -- 2.11.0
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