Re: [PATCH][next] wifi: rtw89: coex: Fix __write_overflow_field error

[Gustavo A. R. Silva]

On 5/23/23 20:21, Ping-Ke Shih wrote:
> > -----Original Message-----
> > From: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
> > Sent: Wednesday, May 24, 2023 10:13 AM
> > To: Ping-Ke Shih <pkshih@xxxxxxxxxxx>; Kalle Valo <kvalo@xxxxxxxxxx>
> > Cc: linux-wireless@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Gustavo A. R. Silva
> > <gustavoars@xxxxxxxxxx>; linux-hardening@xxxxxxxxxxxxxxx
> > Subject: [PATCH][next] wifi: rtw89: coex: Fix __write_overflow_field error
> >
> > One-element arrays as fake flexible arrays are deprecated, and we are
> > moving towards adopting C99 flexible-array members instead.
> >
> > Fix the following error seen under GCC-13 and -fstrict-flex-arrays=3:
> > In function ‘fortify_memcpy_chk’,
> >      inlined from ‘_append_tdma’ at drivers/net/wireless/realtek/rtw89/coex.c:1579:3:
> > include/linux/fortify-string.h:583:25: error: call to ‘__write_overflow_field’ declared with attribute
> > warning: detected write beyond size of field (1st parameter); maybe use struct_group()?
> > [-Werror=attribute-warning]
> >    583 |                         __write_overflow_field(p_size_field, size);
> >        |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >
> > This helps with the ongoing efforts to tighten the FORTIFY_SOURCE
> > routines on memcpy() and help us make progress towards globally
> > enabling -fstrict-flex-arrays=3 [1].
> >
> > This results in no differences in binary output.
> >
> > Link: https://github.com/KSPP/linux/issues/21
> > Link: https://github.com/KSPP/linux/issues/299
> > Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.html [1]
> > Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
> > ---
> >   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 3a586a971e8f..bda0e1e99a8c 100644
> > --- a/drivers/net/wireless/realtek/rtw89/coex.c
> > +++ b/drivers/net/wireless/realtek/rtw89/coex.c
> > @@ -206,7 +206,7 @@ static const struct rtw89_btc_ver rtw89_btc_ver_defs[] = {
> >   struct rtw89_btc_btf_tlv {
> >          u8 type;
> >          u8 len;
> > -       u8 val[1];
> > +       u8 val[];
> >   } __packed;
> >
> >   enum btc_btf_set_report_en {
>
> Arnd has sent the same patch [1] as yours.

Oh that's great! What a coincidence. :)

Thanks for letting me know.
--
Gustavo

> [1] https://lore.kernel.org/linux-wireless/27a7010de8be4006a3e4b95e851781c6@xxxxxxxxxxx/T/#mca619c8261b87b88eedd391ceafb34c40d513ce5