lkml.org 
[lkml]   [2023]   [Sep]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH] media: v4l2-event: Annotate struct v4l2_subscribed_event with __counted_by
From


On 9/22/23 11:49, 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 v4l2_subscribed_event.
> Additionally, since the element count member must be set before accessing
> the annotated flexible array member, move its initialization earlier.
>
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
>
> Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
> Cc: Hans Verkuil <hverkuil-cisco@xs4all.nl>
> Cc: lijian <lijian@yulong.com>
> 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/v4l2-core/v4l2-event.c | 2 +-
> include/media/v4l2-event.h | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/v4l2-core/v4l2-event.c b/drivers/media/v4l2-core/v4l2-event.c
> index c5ce9f11ad7b..3898ff7edddb 100644
> --- a/drivers/media/v4l2-core/v4l2-event.c
> +++ b/drivers/media/v4l2-core/v4l2-event.c
> @@ -238,6 +238,7 @@ int v4l2_event_subscribe(struct v4l2_fh *fh,
> sev = kvzalloc(struct_size(sev, events, elems), GFP_KERNEL);
> if (!sev)
> return -ENOMEM;
> + sev->elems = elems;
> for (i = 0; i < elems; i++)
> sev->events[i].sev = sev;
> sev->type = sub->type;
> @@ -245,7 +246,6 @@ int v4l2_event_subscribe(struct v4l2_fh *fh,
> sev->flags = sub->flags;
> sev->fh = fh;
> sev->ops = ops;
> - sev->elems = elems;
>
> mutex_lock(&fh->subscribe_lock);
>
> diff --git a/include/media/v4l2-event.h b/include/media/v4l2-event.h
> index 4ffa914ade3a..3a0e2588361c 100644
> --- a/include/media/v4l2-event.h
> +++ b/include/media/v4l2-event.h
> @@ -78,7 +78,7 @@ struct v4l2_subscribed_event {
> unsigned int elems;
> unsigned int first;
> unsigned int in_use;
> - struct v4l2_kevent events[];
> + struct v4l2_kevent events[] __counted_by(elems);
> };
>
> /**

\
 
 \ /
  Last update: 2023-09-23 10:25    [W:0.135 / U:0.020 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site