pc-dimm: fix crash when invalid slot number is used

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>
Message-Id: <20190723160859.27250-1-imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Li Qiang <liq3ea@gmail.com>
Signed-off-by: Igor Mammedov &lt;<a href="mailto:imammedo@redhat.com" target="_blank">imammedo@redhat.com</a>&gt;<br></blockquote><div><br></div><div>Reviewed-by: Li Qiang &lt;<a href="mailto:liq3ea@gmail.com">liq3ea@gmail.com</a>&gt;<br></div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
Reviewed-by: Pankaj Gupta <pagupta@redhat.com>

diff --git a/hw/mem/pc-dimm.c b/hw/mem/pc-dimm.c
index b1239fd0d37872d30210f310766519a3e63f825e..29c785799c1cfef246b8f5ea62624cc5b054c1ef 100644 (file)
--- 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) {