[PATCH 29/32] ACPICA: acpi_resource_irq: Replace 1-element arrays with flexible array

Rafael J. Wysocki
2023-04-05T14:00:57Z

From: Kees Cook <kees@outflux.net>

ACPICA commit bfdd3446e7caf795c85c70326c137023942972c5

Similar to "Replace one-element array with flexible-array", replace the
1-element array with a proper flexible array member as defined by C99.

This allows the code to operate without tripping compile-time and run-
time bounds checkers (e.g. via __builtin_object_size(), -fsanitize=bounds,
and/or -fstrict-flex-arrays=3). Note that the spec requires there be at
least one interrupt, so use a union to keep space allocated for this.

The only binary change in .text and .data sections is some rearrangement
by the compiler of acpi_dm_address_common(), but appears to be harmless.

Link: https://github.com/acpica/acpica/commit/bfdd3446
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
drivers/acpi/acpica/amlresrc.h | 5 ++++-
include/acpi/acrestyp.h | 10 ++++++++--
2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/acpi/acpica/amlresrc.h b/drivers/acpi/acpica/amlresrc.h
index 48df447ef5bb..4e88f9fc2a28 100644
--- a/drivers/acpi/acpica/amlresrc.h
+++ b/drivers/acpi/acpica/amlresrc.h
@@ -261,7 +261,10 @@ struct aml_resource_address16 {
struct aml_resource_extended_irq {
AML_RESOURCE_LARGE_HEADER_COMMON u8 flags;
u8 interrupt_count;
- u32 interrupts[1];
+ union {
+ u32 interrupt;
+ ACPI_FLEX_ARRAY(u32, interrupts);
+ };
/* res_source_index, res_source optional fields follow */
};

diff --git a/include/acpi/acrestyp.h b/include/acpi/acrestyp.h
index 4c3b7b393f82..b84cd316217f 100644
--- a/include/acpi/acrestyp.h
+++ b/include/acpi/acrestyp.h
@@ -142,7 +142,10 @@ struct acpi_resource_irq {
u8 shareable;
u8 wake_capable;
u8 interrupt_count;
- u8 interrupts[1];
+ union {
+ u8 interrupt;
+ ACPI_FLEX_ARRAY(u8, interrupts);
+ };
};

struct acpi_resource_dma {
@@ -335,7 +338,10 @@ struct acpi_resource_extended_irq {
u8 wake_capable;
u8 interrupt_count;
struct acpi_resource_source resource_source;
- u32 interrupts[1];
+ union {
+ u32 interrupt;
+ ACPI_FLEX_ARRAY(u32, interrupts);
+ };
};

struct acpi_resource_generic_register {
--
2.35.3