Re: [PATCH] wifi: brcmfmac: Replace 1-element arrays with flexible arrays

[Linus Walleij]

On Wed, Sep 13, 2023 at 8:54 AM Juerg Haefliger
<juerg.haefliger@xxxxxxxxxxxxx> wrote:

> Since commit 2d47c6956ab3 ("ubsan: Tighten UBSAN_BOUNDS on GCC"),
> UBSAN_BOUNDS no longer pretends 1-element arrays are unbounded. Walking
> 'element' and 'channel_list' will trigger warnings, so make them proper
> flexible arrays.
>
> False positive warnings were:
>
>   UBSAN: array-index-out-of-bounds in drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c:6984:20
>   index 1 is out of range for type '__le32 [1]'
>
>   UBSAN: array-index-out-of-bounds in drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c:1126:27
>   index 1 is out of range for type '__le16 [1]'
>
> for these lines of code:
>
>   6884  ch.chspec = (u16)le32_to_cpu(list->element[i]);
>
>   1126  params_le->channel_list[i] = cpu_to_le16(chanspec);
>
> Signed-off-by: Juerg Haefliger <juerg.haefliger@xxxxxxxxxxxxx>

Obviously the right solution, thanks for looking into this!
Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>

Yours,
Linus Walleij