[Qemu-devel] [PATCH] vmw_pvscsi: check message ring page count at initialisation

[P J P]

Vmware Paravirtual SCSI emulation uses command descriptors to
process SCSI commands. These come with their message ring buffers.
A guest could set the message ring page count to an arbitrary value
resulting in infinite loop. Add check to avoid it.

Reported-by: YY Z <address@hidden>
Signed-off-by: P J P <address@hidden>
---
 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 7557546..4a106da 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;
-- 
2.9.3