6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: ikaros [ Upstream commit 945e87267cfd90937b3c637f87324cbb56998b72 ] Fix use-after-free issue in acpi_ds_terminate_control_method() by clearing references to method locals and arguments. Link: https://github.com/acpica/acpica/commit/36f22a94cb1b Signed-off-by: ikaros Signed-off-by: Rafael J. Wysocki Link: https://patch.msgid.link/8730924.NyiUUSuA9g@rafael.j.wysocki Signed-off-by: Sasha Levin --- drivers/acpi/acpica/dsmethod.c | 43 ++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) diff --git a/drivers/acpi/acpica/dsmethod.c b/drivers/acpi/acpica/dsmethod.c index 6168597a96e6f..d0096425468cb 100644 --- a/drivers/acpi/acpica/dsmethod.c +++ b/drivers/acpi/acpica/dsmethod.c @@ -698,6 +698,8 @@ void acpi_ds_terminate_control_method(union acpi_operand_object *method_desc, struct acpi_walk_state *walk_state) { + u32 i; + struct acpi_namespace_node *ref_node; ACPI_FUNCTION_TRACE_PTR(ds_terminate_control_method, walk_state); @@ -708,6 +710,47 @@ acpi_ds_terminate_control_method(union acpi_operand_object *method_desc, } if (walk_state) { + /* + * Check if the return value is a ref_of reference to a method local + * or argument. If so, clear the reference to avoid use-after-free + * when the walk state is deleted. + */ + if (walk_state->return_desc && + (walk_state->return_desc->common.type == + ACPI_TYPE_LOCAL_REFERENCE) + && (walk_state->return_desc->reference.class == + ACPI_REFCLASS_REFOF)) { + ref_node = walk_state->return_desc->reference.object; + if (ref_node) { + + /* Check against method locals */ + for (i = 0; i < ACPI_METHOD_NUM_LOCALS; i++) { + if (ref_node == + &walk_state->local_variables[i]) { + acpi_ut_remove_reference + (walk_state->return_desc); + walk_state->return_desc = NULL; + break; + } + } + + /* Check against method arguments if not already cleared */ + if (walk_state->return_desc) { + for (i = 0; i < ACPI_METHOD_NUM_ARGS; + i++) { + if (ref_node == + &walk_state->arguments[i]) { + acpi_ut_remove_reference + (walk_state-> + return_desc); + walk_state-> + return_desc = NULL; + break; + } + } + } + } + } /* Delete all arguments and locals */ -- 2.53.0