2023-09-22 23:40:47

by Kees Cook

Subject: [PATCH] i3c: dw: Annotate struct dw_i3c_xfer 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 dw_i3c_xfer.

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

Cc: Alexandre Belloni <[email protected]>
Cc: Jeremy Kerr <[email protected]>
Cc: Joel Stanley <[email protected]>
Cc: [email protected]
Signed-off-by: Kees Cook <[email protected]>
---
drivers/i3c/master/dw-i3c-master.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/i3c/master/dw-i3c-master.c b/drivers/i3c/master/dw-i3c-master.c
index 9332ae5f6419..ef5751e91cc9 100644
--- a/drivers/i3c/master/dw-i3c-master.c
+++ b/drivers/i3c/master/dw-i3c-master.c
@@ -233,7 +233,7 @@ struct dw_i3c_xfer {
struct completion comp;
int ret;
unsigned int ncmds;
- struct dw_i3c_cmd cmds[];
+ struct dw_i3c_cmd cmds[] __counted_by(ncmds);
};

struct dw_i3c_i2c_dev_data {
--
2.34.1

2023-09-23 03:51:44

by Jeremy Kerr

Subject: Re: [PATCH] i3c: dw: Annotate struct dw_i3c_xfer with __counted_by

Hi Kees,

> 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).

Nice!

Reviewed-by: Jeremy Kerr <[email protected]>

Cheers,


Jeremy

2023-09-23 08:59:44

by Gustavo A. R. Silva

Subject: Re: [PATCH] i3c: dw: Annotate struct dw_i3c_xfer with __counted_by

On Fri, Sep 22, 2023 at 10:50:11AM -0700, 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 dw_i3c_xfer.
>
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
>
> Cc: Alexandre Belloni <[email protected]>
> Cc: Jeremy Kerr <[email protected]>
> Cc: Joel Stanley <[email protected]>
> Cc: [email protected]
> Signed-off-by: Kees Cook <[email protected]>

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

Thanks
--
Gustavo

> ---
> drivers/i3c/master/dw-i3c-master.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/i3c/master/dw-i3c-master.c b/drivers/i3c/master/dw-i3c-master.c
> index 9332ae5f6419..ef5751e91cc9 100644
> --- a/drivers/i3c/master/dw-i3c-master.c
> +++ b/drivers/i3c/master/dw-i3c-master.c
> @@ -233,7 +233,7 @@ struct dw_i3c_xfer {
> struct completion comp;
> int ret;
> unsigned int ncmds;
> - struct dw_i3c_cmd cmds[];
> + struct dw_i3c_cmd cmds[] __counted_by(ncmds);
> };
>
> struct dw_i3c_i2c_dev_data {
> --
> 2.34.1
>
>

2023-09-25 21:39:17

by Alexandre Belloni

Subject: Re: [PATCH] i3c: dw: Annotate struct dw_i3c_xfer with __counted_by

On Fri, 22 Sep 2023 10:50:11 -0700, 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 dw_i3c_xfer.
>
> [...]

Applied, thanks!

[1/1] i3c: dw: Annotate struct dw_i3c_xfer with __counted_by
commit: 014c9a0e6f9ff573099051e1e2ff6efc3470d02d

Best regards,

--
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com