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Subject: Re: [PATCH 1/5] brcmfmac: To fix kernel crash on out of boundary
 access
To:     Wright Feng <wright.feng@cypress.com>,
        linux-wireless@vger.kernel.org
Cc:     brcm80211-dev-list@broadcom.com, brcm80211-dev-list@cypress.com,
        Arend van Spriel <arend.vanspriel@broadcom.com>,
        Franky Lin <franky.lin@broadcom.com>,
        Hante Meuleman <hante.meuleman@broadcom.com>,
        Kalle Valo <kvalo@codeaurora.org>, chi-hsien.lin@cypress.com,
        Raveendran Somu <raveendran.somu@cypress.com>
References: <20200601071953.23252-1-wright.feng@cypress.com>
 <20200601071953.23252-2-wright.feng@cypress.com>
From:   Florian Fainelli <f.fainelli@gmail.com>
Message-ID: <8fe5fdf5-1b26-a127-3567-321017455a49@gmail.com>
Date:   Mon, 1 Jun 2020 21:34:50 -0700
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On 6/1/2020 12:19 AM, Wright Feng wrote:
> From: Raveendran Somu <raveendran.somu@cypress.com>
> 
> To trunkcate the addtional bytes, if extra bytes been received.

typo: truncate. Missing "have been received".

> Current code only have a warning and proceed without handling it.
> But in one of the crash reported by DVT, these causes the
> crash intermittently. So the processing is limit to the skb->len.
> 
> Signed-off-by: Raveendran Somu <raveendran.somu@cypress.com>
> Signed-off-by: Chi-hsien Lin <chi-hsien.lin@cypress.com>
> Signed-off-by: Wright Feng <wright.feng@cypress.com>
> ---
>  drivers/net/wireless/broadcom/brcm80211/brcmfmac/fwsignal.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fwsignal.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fwsignal.c
> index 09701262330d..531fe9be4025 100644
> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fwsignal.c
> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fwsignal.c
> @@ -1843,6 +1843,9 @@ void brcmf_fws_hdrpull(struct brcmf_if *ifp, s16 siglen, struct sk_buff *skb)
>  
>  	WARN_ON(siglen > skb->len);
>  
> +	if (siglen > skb->len)
> +		siglen = skb->len;

Does it make sense to keep the WARN_ON() one live above then?

> +
>  	if (!siglen)
>  		return;
>  	/* if flow control disabled, skip to packet data and leave */
> 

-- 
Florian