diff mbox

virtio-scsi: fix use-after-free of VirtIOSCSIReq

Message ID 1412761044-25859-1-git-send-email-pbonzini@redhat.com
State New
Headers show

Commit Message

Paolo Bonzini Oct. 8, 2014, 9:37 a.m. UTC 
scsi_req_continue can complete the request and cause the VirtIOSCSIReq
to be freed.  Fetch req->sreq just once to avoid the bug.

Reported-by: Richard Jones <rjones@redhat.com>
Tested-by: Richard Jones <rjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 hw/scsi/virtio-scsi.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

Comments

Fam Zheng Oct. 9, 2014, 6 a.m. UTC | #1 
On Wed, 10/08 11:37, Paolo Bonzini wrote:
> scsi_req_continue can complete the request and cause the VirtIOSCSIReq
> to be freed.  Fetch req->sreq just once to avoid the bug.
> 
> Reported-by: Richard Jones <rjones@redhat.com>
> Tested-by: Richard Jones <rjones@redhat.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  hw/scsi/virtio-scsi.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
> index 203e624..6c02fe2 100644
> --- a/hw/scsi/virtio-scsi.c
> +++ b/hw/scsi/virtio-scsi.c
> @@ -545,11 +545,12 @@ bool virtio_scsi_handle_cmd_req_prepare(VirtIOSCSI *s, VirtIOSCSIReq *req)
>  
>  void virtio_scsi_handle_cmd_req_submit(VirtIOSCSI *s, VirtIOSCSIReq *req)
>  {
> -    if (scsi_req_enqueue(req->sreq)) {
> -        scsi_req_continue(req->sreq);
> +    SCSIRequest *sreq = req->sreq;
> +    if (scsi_req_enqueue(sreq)) {
> +        scsi_req_continue(sreq);
>      }
> -    bdrv_io_unplug(req->sreq->dev->conf.bs);
> -    scsi_req_unref(req->sreq);
> +    bdrv_io_unplug(sreq->dev->conf.bs);
> +    scsi_req_unref(sreq);
>  }
>  
>  static void virtio_scsi_handle_cmd(VirtIODevice *vdev, VirtQueue *vq)
> -- 
> 1.8.3.1
> 
Reviewed-by: Fam Zheng <famz@redhat.com>
diff mbox

Patch

diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
index 203e624..6c02fe2 100644
--- a/hw/scsi/virtio-scsi.c
+++ b/hw/scsi/virtio-scsi.c
@@ -545,11 +545,12 @@  bool virtio_scsi_handle_cmd_req_prepare(VirtIOSCSI *s, VirtIOSCSIReq *req)
 
 void virtio_scsi_handle_cmd_req_submit(VirtIOSCSI *s, VirtIOSCSIReq *req)
 {
-    if (scsi_req_enqueue(req->sreq)) {
-        scsi_req_continue(req->sreq);
+    SCSIRequest *sreq = req->sreq;
+    if (scsi_req_enqueue(sreq)) {
+        scsi_req_continue(sreq);
     }
-    bdrv_io_unplug(req->sreq->dev->conf.bs);
-    scsi_req_unref(req->sreq);
+    bdrv_io_unplug(sreq->dev->conf.bs);
+    scsi_req_unref(sreq);
 }
 
 static void virtio_scsi_handle_cmd(VirtIODevice *vdev, VirtQueue *vq)