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Subject: Re: [PATCH] rtlwifi: rtl_pci: Fix problem of too small skb->len
To:     Larry Finger <Larry.Finger@lwfinger.net>, kvalo@codeaurora.org
Cc:     linux-wireless@vger.kernel.org, pkshih@realtek.com,
        Stable <stable@vger.kernel.org>
References: <20191019190222.29681-1-Larry.Finger@lwfinger.net>
From:   "ian.schram" <ian.schram@telenet.be>
Message-ID: <05f25c80-51a9-bfad-ea4a-3c17b0eecf64@telenet.be>
Date:   Sun, 20 Oct 2019 00:23:51 +0200
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Hi,


This patch doesn't appear to do anything? The increased length is not actually
used, is a part of the patch missing?


ps: superficial reading, i am not hampered by any specific knowledge of this driver.

On 2019-10-19 21:02, Larry Finger wrote:
> In commit 8020919a9b99 ("mac80211: Properly handle SKB with radiotap
> only"), buffers whose length is too short cause a WARN_ON(1) to be
> executed. This change exposed a fault in rtlwifi drivers, which is fixed
> by increasing the length of the affected buffer before it is sent to
> mac80211.
> 
> Cc: Stable <stable@vger.kernel.org> # v5.0+
> Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
> ---
> 
> Kalle,
> 
> Please send to v5.4.
> 
> Larry
> ---
> 
>   drivers/net/wireless/realtek/rtlwifi/pci.c | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/net/wireless/realtek/rtlwifi/pci.c b/drivers/net/wireless/realtek/rtlwifi/pci.c
> index 6087ec7a90a6..bb5144b7c64f 100644
> --- a/drivers/net/wireless/realtek/rtlwifi/pci.c
> +++ b/drivers/net/wireless/realtek/rtlwifi/pci.c
> @@ -692,7 +692,10 @@ static void _rtl_pci_rx_to_mac80211(struct ieee80211_hw *hw,
>   		dev_kfree_skb_any(skb);
>   	} else {
>   		struct sk_buff *uskb = NULL;
> +		int len = skb->len;
>   
> +		if (unlikely(len <= FCS_LEN))
> +			len = FCS_LEN + 2;
>   		uskb = dev_alloc_skb(skb->len + 128);
>   		if (likely(uskb)) {
>   			memcpy(IEEE80211_SKB_RXCB(uskb), &rx_status,
>