From e4be66e5f36b8cd2a052ba9e2ba063e6c37f5453 Mon Sep 17 00:00:00 2001 From: Jacob Keller Date: Mon, 27 Feb 2023 13:41:27 -0800 Subject: [PATCH] vhost: use struct_size and size_add to compute flex array sizes The vhost_get_avail_size and vhost_get_used_size functions compute the size of structures with flexible array members with an additional 2 bytes if the VIRTIO_RING_F_EVENT_IDX feature flag is set. Convert these functions to use struct_size() and size_add() instead of coding the calculation by hand. This ensures that the calculations will saturate at SIZE_MAX rather than overflowing. Signed-off-by: Jacob Keller Cc: "Michael S. Tsirkin" Cc: Jason Wang Cc: virtualization@lists.linux-foundation.org Cc: kvm@vger.kernel.org Message-Id: <20230227214127.3678392-1-jacob.e.keller@intel.com> Signed-off-by: Michael S. Tsirkin --- drivers/vhost/vhost.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index f11bdbe4c2c5..43fa626d4e44 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -436,8 +436,7 @@ static size_t vhost_get_avail_size(struct vhost_virtqueue *vq, size_t event __maybe_unused = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0; - return sizeof(*vq->avail) + - sizeof(*vq->avail->ring) * num + event; + return size_add(struct_size(vq->avail, ring, num), event); } static size_t vhost_get_used_size(struct vhost_virtqueue *vq, @@ -446,8 +445,7 @@ static size_t vhost_get_used_size(struct vhost_virtqueue *vq, size_t event __maybe_unused = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0; - return sizeof(*vq->used) + - sizeof(*vq->used->ring) * num + event; + return size_add(struct_size(vq->used, ring, num), event); } static size_t vhost_get_desc_size(struct vhost_virtqueue *vq,