2022-02-17 03:37:41

by Gustavo A. R. Silva

Subject: [PATCH][next] ACPICA: iASL: Replace zero-length array with flexible-array member

There is a regular need in the kernel to provide a way to declare
having a dynamically sized set of trailing elements in a structure.
Kernel code should always use “flexible array members”[1] for these
cases. The older style of one-element or zero-length arrays should
no longer be used[2].

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.16/process/deprecated.html#zero-length-and-one-element-arrays

Link: https://github.com/KSPP/linux/issues/78
Signed-off-by: Gustavo A. R. Silva <[email protected]>
---
include/acpi/actbl2.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/acpi/actbl2.h b/include/acpi/actbl2.h
index 16847c8d9d5f..9ee4d1b39125 100644
--- a/include/acpi/actbl2.h
+++ b/include/acpi/actbl2.h
@@ -2319,7 +2319,7 @@ struct acpi_table_rgrt {
u16 version;
u8 image_type;
u8 reserved;
- u8 image[0];
+ u8 image[];
};

/* image_type values */
--
2.27.0

2022-02-17 07:24:22

by Kees Cook

Subject: Re: [PATCH][next] ACPICA: iASL: Replace zero-length array with flexible-array member

On Wed, Feb 16, 2022 at 02:32:40PM -0600, Gustavo A. R. Silva wrote:
> There is a regular need in the kernel to provide a way to declare
> having a dynamically sized set of trailing elements in a structure.
> Kernel code should always use “flexible array members”[1] for these
> cases. The older style of one-element or zero-length arrays should
> no longer be used[2].
>
> [1] https://en.wikipedia.org/wiki/Flexible_array_member
> [2] https://www.kernel.org/doc/html/v5.16/process/deprecated.html#zero-length-and-one-element-arrays
>
> Link: https://github.com/KSPP/linux/issues/78
> Signed-off-by: Gustavo A. R. Silva <[email protected]>

Reviewed-by: Kees Cook <[email protected]>

--
Kees Cook

2022-02-19 00:45:21

by Gustavo A. R. Silva

Subject: Re: [PATCH][next] ACPICA: iASL: Replace zero-length array with flexible-array member

On Fri, Feb 18, 2022 at 08:47:15PM +0100, Rafael J. Wysocki wrote:
> On Wed, Feb 16, 2022 at 9:36 PM Kees Cook <[email protected]> wrote:
>
> I've created an upstream ACPICA pull request for this change, thanks!

Great.

Thanks, Rafael.
--
Gustavo

2022-02-19 02:43:30

by Rafael J. Wysocki

Subject: Re: [PATCH][next] ACPICA: iASL: Replace zero-length array with flexible-array member

On Wed, Feb 16, 2022 at 9:36 PM Kees Cook <[email protected]> wrote:
>
> On Wed, Feb 16, 2022 at 02:32:40PM -0600, Gustavo A. R. Silva wrote:
> > There is a regular need in the kernel to provide a way to declare
> > having a dynamically sized set of trailing elements in a structure.
> > Kernel code should always use “flexible array members”[1] for these
> > cases. The older style of one-element or zero-length arrays should
> > no longer be used[2].
> >
> > [1] https://en.wikipedia.org/wiki/Flexible_array_member
> > [2] https://www.kernel.org/doc/html/v5.16/process/deprecated.html#zero-length-and-one-element-arrays
> >
> > Link: https://github.com/KSPP/linux/issues/78
> > Signed-off-by: Gustavo A. R. Silva <[email protected]>
>
> Reviewed-by: Kees Cook <[email protected]>

I've created an upstream ACPICA pull request for this change, thanks!