ACPICA: Fix possible fault if return Package objects contain NULL elements

For predefined name validation. Also adds a warning if a NULL
element is followed by any non-null elements.  ACPICA BZ 813, 814.

http://www.acpica.org/bugzilla/show_bug.cgi?id=813
http://www.acpica.org/bugzilla/show_bug.cgi?id=814

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 42 insertions, 1 deletions

diff --git a/drivers/acpi/acpica/nspredef.c b/drivers/acpi/acpica/nspredef.c
index f8427afeebdf..40280981033e 100644
--- a/drivers/acpi/acpica/nspredef.c
+++ b/drivers/acpi/acpica/nspredef.c
@@ -601,7 +601,8 @@ acpi_ns_check_package(struct acpi_predefined_data *data,
                  * there is only one entry). We may be able to repair this by
                  * wrapping the returned Package with a new outer Package.
                  */
-                if ((*elements)->common.type != ACPI_TYPE_PACKAGE) {
+                if (*elements
+                    && ((*elements)->common.type != ACPI_TYPE_PACKAGE)) {
 
                         /* Create the new outer package and populate it */
 
@@ -673,6 +674,7 @@ acpi_ns_check_package_list(struct acpi_predefined_data *data,
         union acpi_operand_object *sub_package;
         union acpi_operand_object **sub_elements;
         acpi_status status;
+        u8 non_trailing_null = FALSE;
         u32 expected_count;
         u32 i;
         u32 j;
@@ -680,6 +682,45 @@ acpi_ns_check_package_list(struct acpi_predefined_data *data,
         /* Validate each sub-Package in the parent Package */
 
         for (i = 0; i < count; i++) {
+                /*
+                 * Handling for NULL package elements. For now, we will simply allow
+                 * a parent package with trailing NULL elements. This can happen if
+                 * the package was defined to be longer than the initializer list.
+                 * This is legal as per the ACPI specification. It is often used
+                 * to allow for dynamic initialization of a Package.
+                 *
+                 * A future enhancement may be to simply truncate the package to
+                 * remove the trailing NULL elements.
+                 */
+                if (!(*elements)) {
+                        if (!non_trailing_null) {
+
+                                /* Ensure the remaining elements are all NULL */
+
+                                for (j = 1; j < (count - i + 1); j++) {
+                                        if (elements[j]) {
+                                                non_trailing_null = TRUE;
+                                        }
+                                }
+
+                                if (!non_trailing_null) {
+
+                                        /* Ignore the trailing NULL elements */
+
+                                        return (AE_OK);
+                                }
+                        }
+
+                        /* There are trailing non-null elements, issue warning */
+
+                        ACPI_WARN_PREDEFINED((AE_INFO, data->pathname,
+                                              data->node_flags,
+                                              "Found NULL element at package index %u",
+                                              i));
+                        elements++;
+                        continue;
+                }
+
                 sub_package = *elements;
                 sub_elements = sub_package->package.elements;