From e152d8af4220a05c9797591609151d404866beaa Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Fri, 4 Dec 2020 17:23:36 +0300 Subject: [PATCH] virtio_ring: Fix two use after free bugs 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: cbeedb72b97a ("virtio_ring: allocate desc state for split ring separately") Reported-by: Robert Buhren Reported-by: Felicitas Hetzelt Signed-off-by: Dan Carpenter Link: https://lore.kernel.org/r/X8pGaG/zkI3jk8mk@mwanda Signed-off-by: Michael S. Tsirkin Acked-by: Jason Wang --- drivers/virtio/virtio_ring.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 924b6b8..71e16b5 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -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); -- 2.7.4