[Qemu-devel] [PATCH] usb: fix up post load checks

["Michael S. Tsirkin" <mst@redhat.com>]

Correct post load checks:
1. dev->setup_len == sizeof(dev->data_buf)
    seems fine, no need to fail migration
2. When state is DATA, passing index > len
   will cause memcpy with negative length,
   resulting in heap overflow

First of the issues was reported by dgilbert.

Reported-by: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/usb/bus.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/hw/usb/bus.c b/hw/usb/bus.c
index e48b19f..2721719 100644
--- a/hw/usb/bus.c
+++ b/hw/usb/bus.c
@@ -51,8 +51,9 @@ static int usb_device_post_load(void *opaque, int version_id)
     }
     if (dev->setup_index < 0 ||
         dev->setup_len < 0 ||
-        dev->setup_index >= sizeof(dev->data_buf) ||
-        dev->setup_len >= sizeof(dev->data_buf)) {
+        (dev->setup_state == SETUP_STATE_DATA &&
+         dev->setup_index > dev->setup_len) ||
+        dev->setup_len > sizeof(dev->data_buf)) {
         return -EINVAL;
     }
     return 0;
-- 
MST