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From:   Linus Walleij <linus.walleij@linaro.org>
Date:   Wed, 13 Sep 2023 11:28:59 +0200
Message-ID: <CACRpkdaJd9PA96ryKnJbxotT_+sH-qKgOq=xJDQdXXwTvYBC0w@mail.gmail.com>
Subject: Re: [PATCH] wifi: brcmfmac: Replace 1-element arrays with flexible arrays
To:     Juerg Haefliger <juerg.haefliger@canonical.com>
Cc:     aspriel@gmail.com, franky.lin@broadcom.com,
        hante.meuleman@broadcom.com, kvalo@kernel.org,
        linux-wireless@vger.kernel.org,
        brcm80211-dev-list.pdl@broadcom.com,
        SHA-cyfmac-dev-list@infineon.com, linux-kernel@vger.kernel.org,
        marcan@marcan.st, keescook@chromium.org, gustavoars@kernel.org,
        hdegoede@redhat.com, ryohei.kondo@cypress.com
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On Wed, Sep 13, 2023 at 8:54=E2=80=AFAM Juerg Haefliger
<juerg.haefliger@canonical.com> 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/brcm8=
0211/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/brcm8=
0211/brcmfmac/cfg80211.c:1126:27
>   index 1 is out of range for type '__le16 [1]'
>
> for these lines of code:
>
>   6884  ch.chspec =3D (u16)le32_to_cpu(list->element[i]);
>
>   1126  params_le->channel_list[i] =3D cpu_to_le16(chanspec);
>
> Signed-off-by: Juerg Haefliger <juerg.haefliger@canonical.com>

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

Yours,
Linus Walleij