media: amphion: Replace zero-length array with flexible-array member

[PATCH] media: amphion: Replace zero-length array with flexible-array member

Posted by Kees Cook 3 years, 11 months ago

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][3].

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/latest/process/deprecated.html#zero-length-and-one-element-arrays
[3] https://github.com/KSPP/linux/issues/78

Fixes: 9f599f351e86 ("media: amphion: add vpu core driver")
Cc: Ming Qian <ming.qian@nxp.com>
Cc: Shijie Qin <shijie.qin@nxp.com>
Cc: Zhou Peng <eagle.zhou@nxp.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
Cc: linux-media@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/media/platform/amphion/vpu_dbg.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/platform/amphion/vpu_dbg.c b/drivers/media/platform/amphion/vpu_dbg.c
index da62bd718fb8..f72c8a506b22 100644
--- a/drivers/media/platform/amphion/vpu_dbg.c
+++ b/drivers/media/platform/amphion/vpu_dbg.c
@@ -27,7 +27,7 @@ struct print_buf_desc {
 	u32 bytes;
 	u32 read;
 	u32 write;
-	char buffer[0];
+	char buffer[];
 };
 
 static char *vb2_stat_name[] = {
-- 
2.32.0

Re: [PATCH] media: amphion: Replace zero-length array with flexible-array member

Posted by Tommaso Merciai 3 years, 11 months ago

On Fri, May 27, 2022 at 02:29:53PM -0700, Kees Cook 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][3].
> 
> [1] https://en.wikipedia.org/wiki/Flexible_array_member
> [2] https://www.kernel.org/doc/html/latest/process/deprecated.html#zero-length-and-one-element-arrays
> [3] https://github.com/KSPP/linux/issues/78
> 
> Fixes: 9f599f351e86 ("media: amphion: add vpu core driver")
> Cc: Ming Qian <ming.qian@nxp.com>
> Cc: Shijie Qin <shijie.qin@nxp.com>
> Cc: Zhou Peng <eagle.zhou@nxp.com>
> Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
> Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
> Cc: linux-media@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
>  drivers/media/platform/amphion/vpu_dbg.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/media/platform/amphion/vpu_dbg.c b/drivers/media/platform/amphion/vpu_dbg.c
> index da62bd718fb8..f72c8a506b22 100644
> --- a/drivers/media/platform/amphion/vpu_dbg.c
> +++ b/drivers/media/platform/amphion/vpu_dbg.c
> @@ -27,7 +27,7 @@ struct print_buf_desc {
>  	u32 bytes;
>  	u32 read;
>  	u32 write;
> -	char buffer[0];
> +	char buffer[];
>  };
>  
>  static char *vb2_stat_name[] = {
> -- 
> 2.32.0
> 

Hi,
Looks good to me, thanks.

Reviewed-by: Tommaso Merciai <tommaso.merciai@amarulasolutions.com>

-- 
Tommaso Merciai
Embedded Linux Engineer
tommaso.merciai@amarulasolutions.com
__________________________________

Amarula Solutions SRL
Via Le Canevare 30, 31100 Treviso, Veneto, IT
T. +39 042 243 5310
info@amarulasolutions.com
www.amarulasolutions.com

RE: [EXT] [PATCH] media: amphion: Replace zero-length array with flexible-array member

Posted by Ming Qian 3 years, 11 months ago

> From: Kees Cook <keescook@chromium.org>
> Sent: 2022年5月28日 5:30
> To: Ming Qian <ming.qian@nxp.com>
> Cc: Kees Cook <keescook@chromium.org>; Shijie Qin <shijie.qin@nxp.com>;
> Eagle Zhou <eagle.zhou@nxp.com>; Mauro Carvalho Chehab
> <mchehab@kernel.org>; Gustavo A . R . Silva <gustavoars@kernel.org>;
> linux-media@vger.kernel.org; Hans Verkuil <hverkuil-cisco@xs4all.nl>; Nicolas
> Dufresne <nicolas.dufresne@collabora.com>; linux-kernel@vger.kernel.org;
> linux-hardening@vger.kernel.org
> Subject: [EXT] [PATCH] media: amphion: Replace zero-length array with
> flexible-array member
> 
> Caution: EXT Email
> 
> 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][3].
> 
> [1]
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fen.wiki
> pedia.org%2Fwiki%2FFlexible_array_member&amp;data=05%7C01%7Cming.q
> ian%40nxp.com%7C8f4e000999114f77682908da40280bd5%7C686ea1d3bc2
> b4c6fa92cd99c5c301635%7C0%7C0%7C637892837984973240%7CUnknown
> %7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haW
> wiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=DjFIwJC45pAqdCP5EE
> QE7n5F8GH45NdWrQoXunNEhZY%3D&amp;reserved=0
> [2]
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.ke
> rnel.org%2Fdoc%2Fhtml%2Flatest%2Fprocess%2Fdeprecated.html%23zero-len
> gth-and-one-element-arrays&amp;data=05%7C01%7Cming.qian%40nxp.com%
> 7C8f4e000999114f77682908da40280bd5%7C686ea1d3bc2b4c6fa92cd99c5c
> 301635%7C0%7C0%7C637892837984973240%7CUnknown%7CTWFpbGZsb3
> d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%
> 3D%7C3000%7C%7C%7C&amp;sdata=xKvM4qigtFIfvBzNDka44uqTUfloTnNmC
> xPVAhlk5tc%3D&amp;reserved=0
> [3]
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.
> com%2FKSPP%2Flinux%2Fissues%2F78&amp;data=05%7C01%7Cming.qian%4
> 0nxp.com%7C8f4e000999114f77682908da40280bd5%7C686ea1d3bc2b4c6fa
> 92cd99c5c301635%7C0%7C0%7C637892837984973240%7CUnknown%7CT
> WFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJ
> XVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=uzEzW1AEtyWGsmJCHJ%2F
> DfMqa4lCsJjmVfz7KRugzOho%3D&amp;reserved=0
> 
> Fixes: 9f599f351e86 ("media: amphion: add vpu core driver")
> Cc: Ming Qian <ming.qian@nxp.com>
> Cc: Shijie Qin <shijie.qin@nxp.com>
> Cc: Zhou Peng <eagle.zhou@nxp.com>
> Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
> Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
> Cc: linux-media@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>

Reviewed-by: ming_qian <ming.qian@nxp.com>

> ---
>  drivers/media/platform/amphion/vpu_dbg.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/media/platform/amphion/vpu_dbg.c
> b/drivers/media/platform/amphion/vpu_dbg.c
> index da62bd718fb8..f72c8a506b22 100644
> --- a/drivers/media/platform/amphion/vpu_dbg.c
> +++ b/drivers/media/platform/amphion/vpu_dbg.c
> @@ -27,7 +27,7 @@ struct print_buf_desc {
>         u32 bytes;
>         u32 read;
>         u32 write;
> -       char buffer[0];
> +       char buffer[];
>  };
> 
>  static char *vb2_stat_name[] = {
> --
> 2.32.0

Re: [PATCH] media: amphion: Replace zero-length array with flexible-array member

Posted by Gustavo A. R. Silva 3 years, 11 months ago

On Fri, May 27, 2022 at 02:29:53PM -0700, Kees Cook 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][3].
> 
> [1] https://en.wikipedia.org/wiki/Flexible_array_member
> [2] https://www.kernel.org/doc/html/latest/process/deprecated.html#zero-length-and-one-element-arrays
> [3] https://github.com/KSPP/linux/issues/78
> 
> Fixes: 9f599f351e86 ("media: amphion: add vpu core driver")
> Cc: Ming Qian <ming.qian@nxp.com>
> Cc: Shijie Qin <shijie.qin@nxp.com>
> Cc: Zhou Peng <eagle.zhou@nxp.com>
> Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
> Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
> Cc: linux-media@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>

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

Thanks
--
Gustavo

> ---
>  drivers/media/platform/amphion/vpu_dbg.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/media/platform/amphion/vpu_dbg.c b/drivers/media/platform/amphion/vpu_dbg.c
> index da62bd718fb8..f72c8a506b22 100644
> --- a/drivers/media/platform/amphion/vpu_dbg.c
> +++ b/drivers/media/platform/amphion/vpu_dbg.c
> @@ -27,7 +27,7 @@ struct print_buf_desc {
>  	u32 bytes;
>  	u32 read;
>  	u32 write;
> -	char buffer[0];
> +	char buffer[];
>  };
>  
>  static char *vb2_stat_name[] = {
> -- 
> 2.32.0
>