File CVE-2017-8112-qemuu-scsi-vmw_pvscsi-infinite-loop-in-pvscsi_log2.patch of Package xen.6117

References: bsc#1036470 CVE-2017-8112

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(-)

Index: xen-4.5.5-testing/tools/qemu-xen-dir-remote/hw/scsi/vmw_pvscsi.c
===================================================================
--- xen-4.5.5-testing.orig/tools/qemu-xen-dir-remote/hw/scsi/vmw_pvscsi.c
+++ xen-4.5.5-testing/tools/qemu-xen-dir-remote/hw/scsi/vmw_pvscsi.c
@@ -180,7 +180,7 @@ pvscsi_ring_init_msg(PVSCSIRingInfo *m,
     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;