RE: [PATCH 22/32] ACPICA: actbl2: Replace 1-element arrays with flexible arrays

Dan Williams
2023-04-06T00:36:13Z

Rafael J. Wysocki wrote:
> From: Kees Cook <kees@outflux.net>
>
> ACPICA commit 44f1af0664599e87bebc3a1260692baa27b2f264
>
> 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).
>
> The sizeof() uses with struct acpi_nfit_flush_address and struct
> acpi_nfit_smbios have been adjusted to drop the open-coded subtraction
> of the trailing single element. The result is no binary differences in
> .text nor .data sections.
>
> Link: https://github.com/acpica/acpica/commit/44f1af06
> Signed-off-by: Bob Moore <robert.moore@intel.com>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

This one needs the following folded in to pass my tests.

Feel free to fold and add:

Co-developed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

-- >8 --
diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index 981f8b0f595d..85d9d67e38a4 100644
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -894,7 +894,7 @@ static size_t sizeof_flush(struct acpi_nfit_flush_address *flush)
{
if (flush->header.length < sizeof(*flush))
return 0;
- return sizeof(*flush) + sizeof(u64) * (flush->hint_count - 1);
+ return struct_size(flush, hint_address, flush->hint_count);
}

static bool add_flush(struct acpi_nfit_desc *acpi_desc,
diff --git a/tools/testing/nvdimm/test/nfit.c b/tools/testing/nvdimm/test/nfit.c
index c75abb497a1a..745c4a27bc35 100644
--- a/tools/testing/nvdimm/test/nfit.c
+++ b/tools/testing/nvdimm/test/nfit.c
@@ -1878,14 +1878,14 @@ static size_t sizeof_spa(struct acpi_nfit_system_address *spa)
static int nfit_test0_alloc(struct nfit_test *t)
{
struct acpi_nfit_system_address *spa = NULL;
+ struct acpi_nfit_flush_address *flush;
size_t nfit_size = sizeof_spa(spa) * NUM_SPA
+ sizeof(struct acpi_nfit_memory_map) * NUM_MEM
+ sizeof(struct acpi_nfit_control_region) * NUM_DCR
+ offsetof(struct acpi_nfit_control_region,
window_size) * NUM_DCR
+ sizeof(struct acpi_nfit_data_region) * NUM_BDW
- + (sizeof(struct acpi_nfit_flush_address)
- + sizeof(u64) * NUM_HINTS) * NUM_DCR
+ + struct_size(flush, hint_address, NUM_HINTS) * NUM_DCR
+ sizeof(struct acpi_nfit_capabilities);
int i;