Message ID | 151207799957.10789.15658210433260163179.stgit@bahia.lan |
---|---|
State | New |
Headers | show |
Series | vhost: fix error check in vhost_verify_ring_mappings() | expand |
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c index ddc42f0f93ed..6e7d45b01bc8 100644 --- a/hw/virtio/vhost.c +++ b/hw/virtio/vhost.c @@ -493,21 +493,21 @@ static int vhost_verify_ring_mappings(struct vhost_dev *dev, j = 0; r = vhost_verify_ring_part_mapping(dev, vq->desc, vq->desc_phys, vq->desc_size, start_addr, size); - if (!r) { + if (r) { break; } j++; r = vhost_verify_ring_part_mapping(dev, vq->avail, vq->avail_phys, vq->avail_size, start_addr, size); - if (!r) { + if (r) { break; } j++; r = vhost_verify_ring_part_mapping(dev, vq->used, vq->used_phys, vq->used_size, start_addr, size); - if (!r) { + if (r) { break; } }
Since commit f1f9e6c5 "vhost: adapt vhost_verify_ring_mappings() to virtio 1 ring layout", we check the mapping of each part (descriptor table, available ring and used ring) of each virtqueue separately. The checking of a part is done by the vhost_verify_ring_part_mapping() function: it returns either 0 on success or a negative errno if the part cannot be mapped at the same place. Unfortunately, the vhost_verify_ring_mappings() function checks its return value the other way round. It means that we either: - only verify the descriptor table of the first virtqueue, and if it is valid we ignore all the other mappings - or ignore all broken mappings until we reach a valid one ie, we only raise an error if all mappings are broken, and we consider all mappings are valid otherwise (false success), which is obviously wrong. This patch ensures that vhost_verify_ring_mappings() only returns success if ALL mappings are okay. Reported-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Greg Kurz <groug@kaod.org> --- The issue has been around since 2.8, so I don't think this fix is worth an extra rc round. It can be shipped with 2.11.1. --- hw/virtio/vhost.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)