Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

As found with Coccinelle[1], add __counted_by for struct prm_module_info.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Len Brown <lenb@kernel.org>
Cc: linux-acpi@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/acpi/prmt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/acpi/prmt.c b/drivers/acpi/prmt.c
index 7020584096bf..c78453c74ef5 100644
--- a/drivers/acpi/prmt.c
+++ b/drivers/acpi/prmt.c
@@ -69,7 +69,7 @@ struct prm_module_info {
 	bool updatable;
 
 	struct list_head module_list;
-	struct prm_handler_info handlers[];
+	struct prm_handler_info handlers[] __counted_by(handler_count);
 };
 
 static u64 efi_pa_va_lookup(u64 pa)
-- 
2.34.1

On 9/22/23 11:53, Kees Cook wrote:
> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
> (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
> 
> As found with Coccinelle[1], add __counted_by for struct prm_module_info.
> 
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> 
> Cc: "Rafael J. Wysocki" <rafael@kernel.org>
> Cc: Len Brown <lenb@kernel.org>
> Cc: linux-acpi@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>

Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Thanks
-- 
Gustavo

> ---
>   drivers/acpi/prmt.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/acpi/prmt.c b/drivers/acpi/prmt.c
> index 7020584096bf..c78453c74ef5 100644
> --- a/drivers/acpi/prmt.c
> +++ b/drivers/acpi/prmt.c
> @@ -69,7 +69,7 @@ struct prm_module_info {
>   	bool updatable;
>   
>   	struct list_head module_list;
> -	struct prm_handler_info handlers[];
> +	struct prm_handler_info handlers[] __counted_by(handler_count);
>   };
>   
>   static u64 efi_pa_va_lookup(u64 pa)

On Sat, Sep 23, 2023 at 11:41 AM Gustavo A. R. Silva
<gustavo@embeddedor.com> wrote:
>
>
>
> On 9/22/23 11:53, Kees Cook wrote:
> > Prepare for the coming implementation by GCC and Clang of the __counted_by
> > attribute. Flexible array members annotated with __counted_by can have
> > their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
> > (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> > functions).
> >
> > As found with Coccinelle[1], add __counted_by for struct prm_module_info.
> >
> > [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> >
> > Cc: "Rafael J. Wysocki" <rafael@kernel.org>
> > Cc: Len Brown <lenb@kernel.org>
> > Cc: linux-acpi@vger.kernel.org
> > Signed-off-by: Kees Cook <keescook@chromium.org>
>
> Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Applied as 6.7 material, thanks!

> > ---
> >   drivers/acpi/prmt.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/acpi/prmt.c b/drivers/acpi/prmt.c
> > index 7020584096bf..c78453c74ef5 100644
> > --- a/drivers/acpi/prmt.c
> > +++ b/drivers/acpi/prmt.c
> > @@ -69,7 +69,7 @@ struct prm_module_info {
> >       bool updatable;
> >
> >       struct list_head module_list;
> > -     struct prm_handler_info handlers[];
> > +     struct prm_handler_info handlers[] __counted_by(handler_count);
> >   };
> >
> >   static u64 efi_pa_va_lookup(u64 pa)