ACPICA: Validate start object for acpi_walk_namespace.

Perform a sanity check on the start object to prevent problems
later. ACPICA BZ 1025.
This patch only adds additional input parameter validation, no actual
kernel suffering has been discovered.

Buglink: http://bugs.acpica.org/show_bug.cgi?id=1025
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Reviewed-by: Len Brown <len.brown@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/drivers/acpi/acpica/nsxfeval.c b/drivers/acpi/acpica/nsxfeval.c
index b38b4b07f86e..481a6b4a9b2f 100644
--- a/drivers/acpi/acpica/nsxfeval.c
+++ b/drivers/acpi/acpica/nsxfeval.c
@@ -605,11 +605,19 @@ acpi_walk_namespace(acpi_object_type type,
                 goto unlock_and_exit;
         }
 
+        /* Now we can validate the starting node */
+
+        if (!acpi_ns_validate_handle(start_object)) {
+                status = AE_BAD_PARAMETER;
+                goto unlock_and_exit2;
+        }
+
         status = acpi_ns_walk_namespace(type, start_object, max_depth,
                                         ACPI_NS_WALK_UNLOCK,
                                         descending_callback, ascending_callback,
                                         context, return_value);
 
+      unlock_and_exit2:
         (void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
 
       unlock_and_exit: