From: Michael S. Tsirkin Date: Mon, 21 Aug 2017 19:33:33 +0000 (+0300) Subject: vhost: fix end of range for access_ok X-Git-Tag: v4.15-rc1~77^2~2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=ca2c5b33a285723f517fa296b76f7fd36c383dad;p=thirdparty%2Fkernel%2Flinux.git vhost: fix end of range for access_ok 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 Signed-off-by: Michael S. Tsirkin Acked-by: Koichiro Den --- diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index d6dbb28245e6d..33ac2b186b85e 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -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;