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Date:   Sat, 13 Apr 2019 22:27:29 +0300
From:   Dan Carpenter <dan.carpenter@oracle.com>
To:     Colin King <colin.king@canonical.com>
Cc:     Amitkumar Karwar <amitkarwar@gmail.com>,
        Nishant Sarmukadam <nishants@marvell.com>,
        Ganapathi Bhat <gbhat@marvell.com>,
        Xinming Hu <huxinming820@gmail.com>,
        Kalle Valo <kvalo@codeaurora.org>,
        "David S . Miller" <davem@davemloft.net>,
        linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
        kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mwifiex: check for null return from skb_copy
Message-ID: <20190413192729.GL6095@kadam>
References: <20190413161438.6376-1-colin.king@canonical.com>
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On Sat, Apr 13, 2019 at 05:14:38PM +0100, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> It is possible for skb_copy to return a null pointer and currently
> this will cause a null pointer dereference when the function
> mwifiex_uap_queue_bridged_pkt is called.  Fix this by checking for
> a null return from skb_copy and return -ENOMEM.
> 
> Addresses-Coverity: ("Dereference null return")
> Fixes: 838e4f449297 ("mwifiex: improve uAP RX handling")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
>  drivers/net/wireless/marvell/mwifiex/uap_txrx.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/net/wireless/marvell/mwifiex/uap_txrx.c b/drivers/net/wireless/marvell/mwifiex/uap_txrx.c
> index 5ce85d5727e4..b262dc78d638 100644
> --- a/drivers/net/wireless/marvell/mwifiex/uap_txrx.c
> +++ b/drivers/net/wireless/marvell/mwifiex/uap_txrx.c
> @@ -256,6 +256,8 @@ int mwifiex_handle_uap_rx_forward(struct mwifiex_private *priv,
>  
>  	if (is_multicast_ether_addr(ra)) {
>  		skb_uap = skb_copy(skb, GFP_ATOMIC);
> +		if (!skb_uap)
> +			return -ENOMEM;

I think we would want to free dev_kfree_skb_any(skb) before returning.

>  		mwifiex_uap_queue_bridged_pkt(priv, skb_uap);
>  	} else {
>  		if (mwifiex_get_sta_entry(priv, ra)) {

regards,
dan carpenter