2023-09-22 22:54:19

by Kees Cook

Subject: [PATCH] mxser: Annotate struct mxser_board with __counted_by

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 mxser_board.

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

Cc: Jiri Slaby <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Shawn Guo <[email protected]>
Cc: Sascha Hauer <[email protected]>
Cc: Pengutronix Kernel Team <[email protected]>
Cc: Fabio Estevam <[email protected]>
Cc: NXP Linux Team <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Kees Cook <[email protected]>
---
drivers/tty/mxser.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/mxser.c b/drivers/tty/mxser.c
index 10aa4ed38793..6ce7f259968f 100644
--- a/drivers/tty/mxser.c
+++ b/drivers/tty/mxser.c
@@ -288,7 +288,7 @@ struct mxser_board {
enum mxser_must_hwid must_hwid;
speed_t max_baud;

- struct mxser_port ports[];
+ struct mxser_port ports[] __counted_by(nports);
};

static DECLARE_BITMAP(mxser_boards, MXSER_BOARDS);
--
2.34.1

2023-09-23 09:43:02

by Gustavo A. R. Silva

Subject: Re: [PATCH] mxser: Annotate struct mxser_board with __counted_by

On 9/22/23 11:52, 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 mxser_board.
>
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
>
> Cc: Jiri Slaby <[email protected]>
> Cc: Greg Kroah-Hartman <[email protected]>
> Cc: Shawn Guo <[email protected]>
> Cc: Sascha Hauer <[email protected]>
> Cc: Pengutronix Kernel Team <[email protected]>
> Cc: Fabio Estevam <[email protected]>
> Cc: NXP Linux Team <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Signed-off-by: Kees Cook <[email protected]>

Reviewed-by: Gustavo A. R. Silva <[email protected]>

Thanks
--
Gustavo

> ---
> drivers/tty/mxser.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/tty/mxser.c b/drivers/tty/mxser.c
> index 10aa4ed38793..6ce7f259968f 100644
> --- a/drivers/tty/mxser.c
> +++ b/drivers/tty/mxser.c
> @@ -288,7 +288,7 @@ struct mxser_board {
> enum mxser_must_hwid must_hwid;
> speed_t max_baud;
>
> - struct mxser_port ports[];
> + struct mxser_port ports[] __counted_by(nports);
> };
>
> static DECLARE_BITMAP(mxser_boards, MXSER_BOARDS);

2023-09-25 07:56:28

by Jiri Slaby

Subject: Re: [PATCH] mxser: Annotate struct mxser_board with __counted_by

On 22. 09. 23, 19:52, 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 mxser_board.
>
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Reviewed-by: Jiri Slaby <[email protected]>

thanks,
--
js
suse labs