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virtio_ring: Fix two use after free bugs 

[ Upstream commit e152d8af42 ]

The "vq" struct is added to the "vdev->vqs" list prematurely.  If we
encounter an error later in the function then the "vq" is freed, but
since it is still on the list that could lead to a use after free bug.

Fixes: cbeedb72b9 ("virtio_ring: allocate desc state for split ring separately")
Reported-by: Robert Buhren <robert.buhren@sect.tu-berlin.de>
Reported-by: Felicitas Hetzelt <file@sect.tu-berlin.de>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/X8pGaG/zkI3jk8mk@mwanda
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
5.4-rM2-2.2.x-imx-squashed
Dan Carpenter 2020-12-04 17:23:36 +03:00 committed by Greg Kroah-Hartman
parent 2d65ff873d
commit e01dfcc08b
1 changed files with 2 additions and 2 deletions
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4
drivers/virtio/virtio_ring.c
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@ -1608,7 +1608,6 @@ static struct virtqueue *vring_create_virtqueue_packed(
vq->num_added = 0;
vq->packed_ring = true;
vq->use_dma_api = vring_use_dma_api(vdev);
list_add_tail(&vq->vq.list, &vdev->vqs);
#ifdef DEBUG
vq->in_use = false;
vq->last_add_time_valid = false;
@ -1669,6 +1668,7 @@ static struct virtqueue *vring_create_virtqueue_packed(
cpu_to_le16(vq->packed.event_flags_shadow);
}
list_add_tail(&vq->vq.list, &vdev->vqs);
return &vq->vq;
err_desc_extra:
@ -2085,7 +2085,6 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index,
vq->last_used_idx = 0;
vq->num_added = 0;
vq->use_dma_api = vring_use_dma_api(vdev);
list_add_tail(&vq->vq.list, &vdev->vqs);
#ifdef DEBUG
vq->in_use = false;
vq->last_add_time_valid = false;
@ -2127,6 +2126,7 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index,
memset(vq->split.desc_state, 0, vring.num *
sizeof(struct vring_desc_state_split));
list_add_tail(&vq->vq.list, &vdev->vqs);
return &vq->vq;
}
EXPORT_SYMBOL_GPL(__vring_new_virtqueue);