[PATCH] scsi: pm8001: Replace one-element array with flexible-array member

[PATCH] scsi: pm8001: Replace one-element array with flexible-array member

[Gustavo A. R. Silva]

One-element arrays are deprecated, and we are replacing them with flexible
array members instead. So, replace one-element array with flexible-array
member in struct fw_control_info.

This helps with the ongoing efforts to tighten the FORTIFY_SOURCE
routines on memcpy() and help us make progress towards globally
enabling -fstrict-flex-arrays=3 [1].

Link: https://github.com/KSPP/linux/issues/79
Link: https://github.com/KSPP/linux/issues/207
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101836 [1]
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 drivers/scsi/pm8001/pm8001_sas.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/pm8001/pm8001_sas.h b/drivers/scsi/pm8001/pm8001_sas.h
index c5e3f380a01c..b08f52673889 100644
--- a/drivers/scsi/pm8001/pm8001_sas.h
+++ b/drivers/scsi/pm8001/pm8001_sas.h
@@ -612,7 +612,7 @@ struct fw_control_info {
 	operations.*/
 	u32			reserved;/* padding required for 64 bit
 	alignment */
-	u8			buffer[1];/* Start of buffer */
+	u8			buffer[];/* Start of buffer */
 };
 struct fw_control_ex {
 	struct fw_control_info *fw_control;
-- 
2.34.1

Re: [PATCH] scsi: pm8001: Replace one-element array with flexible-array member

[Jinpu Wang]

On Thu, Sep 22, 2022 at 9:30 PM Gustavo A. R. Silva
<gustavoars@kernel.org> wrote:
>
> One-element arrays are deprecated, and we are replacing them with flexible
> array members instead. So, replace one-element array with flexible-array
> member in struct fw_control_info.
>
> This helps with the ongoing efforts to tighten the FORTIFY_SOURCE
> routines on memcpy() and help us make progress towards globally
> enabling -fstrict-flex-arrays=3 [1].
>
> Link: https://github.com/KSPP/linux/issues/79
> Link: https://github.com/KSPP/linux/issues/207
> Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101836 [1]
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Acked-by: Jack Wang <jinpu.wang@ionos.com>
> ---
>  drivers/scsi/pm8001/pm8001_sas.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/scsi/pm8001/pm8001_sas.h b/drivers/scsi/pm8001/pm8001_sas.h
> index c5e3f380a01c..b08f52673889 100644
> --- a/drivers/scsi/pm8001/pm8001_sas.h
> +++ b/drivers/scsi/pm8001/pm8001_sas.h
> @@ -612,7 +612,7 @@ struct fw_control_info {
>         operations.*/
>         u32                     reserved;/* padding required for 64 bit
>         alignment */
> -       u8                      buffer[1];/* Start of buffer */
> +       u8                      buffer[];/* Start of buffer */
>  };
>  struct fw_control_ex {
>         struct fw_control_info *fw_control;
> --
> 2.34.1
>

Re: [PATCH] scsi: pm8001: Replace one-element array with flexible-array member

[Kees Cook]

On Thu, Sep 22, 2022 at 02:30:28PM -0500, Gustavo A. R. Silva wrote:
> One-element arrays are deprecated, and we are replacing them with flexible
> array members instead. So, replace one-element array with flexible-array
> member in struct fw_control_info.

I think this changelog should include some explanation of why this change
is safe. As far as I can see, it would be:

This is the only change needed; struct fw_control_info is only ever used
for casting to existing allocations. No sizeof() is used on any of the
resulting variables.

> This helps with the ongoing efforts to tighten the FORTIFY_SOURCE
> routines on memcpy() and help us make progress towards globally
> enabling -fstrict-flex-arrays=3 [1].
> 
> Link: https://github.com/KSPP/linux/issues/79
> Link: https://github.com/KSPP/linux/issues/207
> Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101836 [1]
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Another one down! :)

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook

Re: [PATCH] scsi: pm8001: Replace one-element array with flexible-array member

[Martin K. Petersen]

Gustavo,

> One-element arrays are deprecated, and we are replacing them with
> flexible array members instead. So, replace one-element array with
> flexible-array member in struct fw_control_info.

Applied to 6.1/scsi-staging, thanks!

-- 
Martin K. Petersen	Oracle Linux Engineering