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Date:   Thu, 14 Sep 2023 09:52:38 -0700
From:   Kees Cook <keescook@chromium.org>
To:     Juerg Haefliger <juerg.haefliger@canonical.com>
Cc:     SHA-cyfmac-dev-list@infineon.com, aspriel@gmail.com,
        brcm80211-dev-list.pdl@broadcom.com, franky.lin@broadcom.com,
        gustavoars@kernel.org, hante.meuleman@broadcom.com,
        hdegoede@redhat.com, kvalo@kernel.org, linus.walleij@linaro.org,
        linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org,
        marcan@marcan.st, ryohei.kondo@cypress.com, stable@vger.kernel.org
Subject: Re: [PATCH v2] wifi: brcmfmac: Replace 1-element arrays with
 flexible arrays
Message-ID: <202309140952.98489A964@keescook>
References: <20230913065421.12615-1-juerg.haefliger@canonical.com>
 <20230914070227.12028-1-juerg.haefliger@canonical.com>
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On Thu, Sep 14, 2023 at 09:02:27AM +0200, Juerg Haefliger 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);
> 
> Cc: stable@vger.kernel.org # 6.5+
> Signed-off-by: Juerg Haefliger <juerg.haefliger@canonical.com>

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook