On Wed, Jun 19, 2024 at 11:40:57AM +0200, Javier Carrasco wrote:
> Use the __counted_by compiler attribute for the data[] flexible array member
> to improve the results of array bound sanitizers.
>
> Signed-off-by: Javier Carrasco <javier.carrasco.cruz@xxxxxxxxx>
> ---
> The size is assigned before the first reference to the flexible array
> (see pkt_add()), which allows for a straightforward annotation without
> further modifications.
Agreed, this seems like a reasonable patch in and of itself that should
work:
Reviewed-by: Nathan Chancellor <nathan@xxxxxxxxxx>
It might also make sense to change the pkt allocation to use
struct_size() instead of open coding it?
diff --git a/drivers/usb/serial/garmin_gps.c b/drivers/usb/serial/garmin_gps.c
index 670e942fdaaa..04946c1cbf6f 100644
--- a/drivers/usb/serial/garmin_gps.c
+++ b/drivers/usb/serial/garmin_gps.c
@@ -267,8 +267,7 @@ static int pkt_add(struct garmin_data *garmin_data_p,
/* process only packets containing data ... */
if (data_length) {
- pkt = kmalloc(sizeof(struct garmin_packet)+data_length,
- GFP_ATOMIC);
+ pkt = kmalloc(struct_size(pkt, data, data_length), GFP_ATOMIC);
if (!pkt)
return 0;
> ---
> drivers/usb/serial/garmin_gps.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/usb/serial/garmin_gps.c b/drivers/usb/serial/garmin_gps.c
> index 670e942fdaaa..57df6ad183ff 100644
> --- a/drivers/usb/serial/garmin_gps.c
> +++ b/drivers/usb/serial/garmin_gps.c
> @@ -104,7 +104,7 @@ struct garmin_packet {
> int seq;
> /* the real size of the data array, always > 0 */
> int size;
> - __u8 data[];
> + __u8 data[] __counted_by(size);
> };
>
> /* structure used to keep the current state of the driver */
>
> ---
> base-commit: 0c52056d9f77508cb6d4d68d3fc91c6c08ec71af
> change-id: 20240619-garmin_gps_counted_by-376545960353
>
> Best regards,
> --
> Javier Carrasco <javier.carrasco.cruz@xxxxxxxxx>
>
