ACPICA: Resource Mgr: Prevent infinite loops in resource walks

Add checks for zero-length resource descriptors in all code that
loops through a resource descriptor list. This prevents possible
infinite loops because the length is used to increment the traveral
pointer and detect the end-of-descriptor.

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/acpi/acpica/rscalc.c b/drivers/acpi/acpica/rscalc.c
index 7816d4eef04e..72077fa1eea5 100644
--- a/drivers/acpi/acpica/rscalc.c
+++ b/drivers/acpi/acpica/rscalc.c
@@ -202,6 +202,12 @@ acpi_rs_get_aml_length(struct acpi_resource * resource, acpi_size * size_needed)
                         return_ACPI_STATUS(AE_AML_INVALID_RESOURCE_TYPE);
                 }
 
+                /* Sanity check the length. It must not be zero, or we loop forever */
+
+                if (!resource->length) {
+                        return_ACPI_STATUS(AE_AML_BAD_RESOURCE_LENGTH);
+                }
+
                 /* Get the base size of the (external stream) resource descriptor */
 
                 total_size = acpi_gbl_aml_resource_sizes[resource->type];