[Qemu-devel] [PATCH] pc-dimm: fix crash when invalid slot number is used

[Igor Mammedov <imammedo@redhat.com>]

QEMU will crash with:
  Segmentation fault (core dumped)
when negative slot number is used, ex:
  qemu-system-x86_64 -m 1G,maxmem=20G,slots=256 \
      -object memory-backend-ram,id=mem1,size=1G \
      -device pc-dimm,id=dimm1,memdev=mem1,slot=-2

fix it by checking that slot number is within valid range.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
---
 hw/mem/pc-dimm.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/hw/mem/pc-dimm.c b/hw/mem/pc-dimm.c
index b1239fd0d3..29c785799c 100644
--- a/hw/mem/pc-dimm.c
+++ b/hw/mem/pc-dimm.c
@@ -38,6 +38,13 @@ void pc_dimm_pre_plug(PCDIMMDevice *dimm, MachineState *machine,
 
     slot = object_property_get_int(OBJECT(dimm), PC_DIMM_SLOT_PROP,
                                    &error_abort);
+    if ((slot < 0 || slot >= machine->ram_slots) &&
+         slot != PC_DIMM_UNASSIGNED_SLOT) {
+        error_setg(&local_err, "invalid slot number, valid range is [0-%"
+                   PRIu64 "]", machine->ram_slots - 1);
+        goto out;
+    }
+
     slot = pc_dimm_get_free_slot(slot == PC_DIMM_UNASSIGNED_SLOT ? NULL : &slot,
                                  machine->ram_slots, &local_err);
     if (local_err) {
-- 
2.18.1