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vhost: fix end of range for access_ok

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During access_ok checks, addr increases as we iterate over the data
structure, thus addr + len - 1 will point beyond the end of region we
are translating.  Harmless since we then verify that the region covers
addr, but let's not waste cpu cycles.

Reported-by: Koichiro Den <den@klaipeden.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Koichiro Den <den@klaipeden.com>
This commit is contained in:
Michael S. Tsirkin 2017-08-21 22:33:33 +03:00
parent 816e85edff
commit ca2c5b33a2
1 changed files with 2 additions and 2 deletions
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4
drivers/vhost/vhost.c
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@ -1175,7 +1175,7 @@ static int iotlb_access_ok(struct vhost_virtqueue *vq,
{
const struct vhost_umem_node *node;
struct vhost_umem *umem = vq->iotlb;
u64 s = 0, size, orig_addr = addr;
u64 s = 0, size, orig_addr = addr, last = addr + len - 1;
if (vhost_vq_meta_fetch(vq, addr, len, type))
return true;
@ -1183,7 +1183,7 @@ static int iotlb_access_ok(struct vhost_virtqueue *vq,
while (len > s) {
node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
addr,
addr + len - 1);
last);
if (node == NULL || node->start > addr) {
vhost_iotlb_miss(vq, addr, access);
return false;