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When a virtqueue size is changed by the guest via
virtio_queue_set_num(), its region cache is not automatically updated.
If the size was increased, this could lead to accessing the cache out
of bounds. For example, in vring_get_used_event():
static inline uint16_t vring_get_used_event(VirtQueue *vq)
{
return vring_avail_ring(vq, vq->vring.num);
}
static inline uint16_t vring_avail_ring(VirtQueue *vq, int i)
{
VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
hwaddr pa = offsetof(VRingAvail, ring[i]);
if (!caches) {
return 0;
}
return virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa);
}
vq->vring.num will be greater than caches->avail.len, which will
trigger a failed assertion down the call path of
virtio_lduw_phys_cached().
Fix this by calling virtio_init_region_cache() after
virtio_queue_set_num() if we are not already calling
virtio_queue_set_rings(). In the legacy path this is already done by
virtio_queue_update_rings().
Signed-off-by: Carlos López <clopez@suse.de>
Message-Id: <20230317002749.27379-1-clopez@suse.de>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Acked-by: Halil Pasic <pasic@linux.ibm.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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| .. | ||
| vdpa-dev.h | ||
| vhost-backend.h | ||
| vhost-scsi-common.h | ||
| vhost-scsi.h | ||
| vhost-user-blk.h | ||
| vhost-user-fs.h | ||
| vhost-user-gpio.h | ||
| vhost-user-i2c.h | ||
| vhost-user-rng.h | ||
| vhost-user-scsi.h | ||
| vhost-user-vsock.h | ||
| vhost-user.h | ||
| vhost-vdpa.h | ||
| vhost-vsock-common.h | ||
| vhost-vsock.h | ||
| vhost.h | ||
| virtio-access.h | ||
| virtio-balloon.h | ||
| virtio-blk-common.h | ||
| virtio-blk.h | ||
| virtio-bus.h | ||
| virtio-crypto.h | ||
| virtio-gpu-bswap.h | ||
| virtio-gpu-pci.h | ||
| virtio-gpu-pixman.h | ||
| virtio-gpu.h | ||
| virtio-input.h | ||
| virtio-iommu.h | ||
| virtio-mem.h | ||
| virtio-mmio.h | ||
| virtio-net.h | ||
| virtio-pci.h | ||
| virtio-pmem.h | ||
| virtio-rng.h | ||
| virtio-scsi.h | ||
| virtio-serial.h | ||
| virtio.h | ||