From: P J P <ppandit@redhat.com>

Date: Tue, 25 Apr 2017 18:36:23 +0530

Subject: [PATCH] vmw_pvscsi: check message ring page count at initialisation

A guest could set the message ring page count to zero, resulting in

infinite loop. Add check to avoid it.

Reported-by: YY Z <bigbird475958471@gmail.com>

Signed-off-by: P J P <ppandit@redhat.com>

Message-Id: <20170425130623.3649-1-ppandit@redhat.com>

Reviewed-by: Dmitry Fleytman <dmitry@daynix.com>

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

(cherry picked from commit f68826989cd4d1217797251339579c57b3c0934e)

---

 hw/scsi/vmw_pvscsi.c | 2 +-

 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/scsi/vmw_pvscsi.c b/hw/scsi/vmw_pvscsi.c

index 75575461e2..4a106da856 100644

--- a/hw/scsi/vmw_pvscsi.c

+++ b/hw/scsi/vmw_pvscsi.c

@@ -202,7 +202,7 @@ pvscsi_ring_init_msg(PVSCSIRingInfo *m, PVSCSICmdDescSetupMsgRing *ri)

     uint32_t len_log2;

     uint32_t ring_size;

-    if (ri->numPages > PVSCSI_SETUP_MSG_RING_MAX_NUM_PAGES) {

+    if (!ri->numPages || ri->numPages > PVSCSI_SETUP_MSG_RING_MAX_NUM_PAGES) {

         return -1;

     }

     ring_size = ri->numPages * PVSCSI_MAX_NUM_MSG_ENTRIES_PER_PAGE;