On Fri, 2023-10-06 at 13:17 -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 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
> rtw89_btc_btf_set_slot_table.
>
> Cc: Ping-Ke Shih <pks...@realtek.com>
> Cc: Kalle Valo <kv...@kernel.org>
> Cc: "Gustavo A. R. Silva" <gustavo...@kernel.org>
> Cc: linux-wirel...@vger.kernel.org
> Cc: linux-hardening@vger.kernel.org
> Link:
> https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> [1]
> Signed-off-by: Kees Cook <keesc...@chromium.org>
> ---
> drivers/net/wireless/realtek/rtw89/coex.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/wireless/realtek/rtw89/coex.c
> b/drivers/net/wireless/realtek/rtw89/coex.c
> index 4ba8b3df70ae..d66a1152c3f5 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[];
> + u8 buf[] __counted_by(tbl_num);
This struct isn't defined properly. It should be
struct rtw89_btc_btf_set_slot_table {
u8 fver;
u8 tbl_num;
struct rtw89_btc_fbtc_slot tbl[] __counted_by(tbl_num);
} __packed;
And, we should modify rtw89_btc_fw_set_slots() as well.
Another struct 'rtw89_btc_btf_set_mon_reg' has similar problem.
So, NACK this patch. I will prepare one or two patches for them next week.
By the way, I have question about __counted_by(). Can I apply it to little/big-
endian 'num'? Like
struct foo {
...
__le32 num;
__le32 data[] __counted_by(num);
}
> } __packed;
>
> struct rtw89_btc_btf_set_mon_reg {
> --
> 2.34.1
>
