On Wed, Oct 11, 2023 at 02:37:24PM +0800, Ping-Ke Shih 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 via CONFIG_UBSAN_BOUNDS (for
> array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
>
> Use struct_size() and flex_array_size() helpers to calculate proper sizes
> for allocation and memcpy().
>
> Don't change logic at all, and result is identical as before.
>
> Cc: Kees Cook <keescook@xxxxxxxxxxxx>
> Signed-off-by: Ping-Ke Shih <pkshih@xxxxxxxxxxx>
Thanks for this!
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
> ---
> drivers/net/wireless/realtek/rtw89/coex.c | 12 +++++-------
> 1 file changed, 5 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/net/wireless/realtek/rtw89/coex.c b/drivers/net/wireless/realtek/rtw89/coex.c
> index 4ba8b3df70ae..9f9da122f3f8 100644
> --- a/drivers/net/wireless/realtek/rtw89/coex.c
> +++ b/drivers/net/wireless/realtek/rtw89/coex.c
> @@ -237,7 +237,7 @@ struct rtw89_btc_btf_set_report {
> struct rtw89_btc_btf_set_slot_table {
> u8 fver;
> u8 tbl_num;
> - u8 buf[];
> + struct rtw89_btc_fbtc_slot tbls[] __counted_by(tbl_num);
> } __packed;
>
> struct rtw89_btc_btf_set_mon_reg {
> @@ -1821,19 +1821,17 @@ static void rtw89_btc_fw_en_rpt(struct rtw89_dev *rtwdev,
> static void rtw89_btc_fw_set_slots(struct rtw89_dev *rtwdev, u8 num,
> struct rtw89_btc_fbtc_slot *s)
> {
> - struct rtw89_btc_btf_set_slot_table *tbl = NULL;
> - u8 *ptr = NULL;
> - u16 n = 0;
> + struct rtw89_btc_btf_set_slot_table *tbl;
> + u16 n;
Using u16 instead of size_t here makes me nervous, but since "num" is
u8, wrap-around isn't possible. :P
--
Kees Cook
