On Fri, Jul 06, 2018 at 03:28:32PM +0200, Arnd Bergmann wrote:
> gcc-8 points out that the fix-byte buffer might be too small if
> desc->mode is a three-digit number:
>
> drivers/usb/typec/class.c: In function 'typec_register_altmode':
> drivers/usb/typec/class.c:502:32: error: '%d' directive writing between 1 and 3 bytes into a region of size 2 [-Werror=format-overflow=]
> sprintf(alt->group_name, "mode%d", desc->mode);
> ^~
> drivers/usb/typec/class.c:502:27: note: directive argument in the range [0, 255]
> sprintf(alt->group_name, "mode%d", desc->mode);
> ^~~~~~~~
> drivers/usb/typec/class.c:502:2: note: 'sprintf' output between 6 and 8 bytes into a destination of size 6
> sprintf(alt->group_name, "mode%d", desc->mode);
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> I assume this cannot happen in practice, but we can simply make the
> string long enough to avoid the warning. This uses the two padding
> bytes that already exist after the string.
>
> Fixes: 4ab8c18d4d67 ("usb: typec: Register a device for every mode")
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Acked-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> ---
> drivers/usb/typec/bus.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/usb/typec/bus.h b/drivers/usb/typec/bus.h
> index 62aaf8b56bde..db40e61d8b72 100644
> --- a/drivers/usb/typec/bus.h
> +++ b/drivers/usb/typec/bus.h
> @@ -16,7 +16,7 @@ struct altmode {
> enum typec_port_data roles;
>
> struct attribute *attrs[5];
> - char group_name[6];
> + char group_name[8];
> struct attribute_group group;
> const struct attribute_group *groups[2];
>
Thanks,
--
heikki
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