Re: [PATCH net 1/2] net: socionext: fix possible user-after-free in netsec_process_rx

[Ilias Apalodimas <ilias.apalodimas@linaro.org>]

On Sat, Jan 25, 2020 at 12:48:50PM +0100, Lorenzo Bianconi wrote:
> Fix possible use-after-free in in netsec_process_rx that can occurs if
> the first packet is sent to the normal networking stack and the
> following one is dropped by the bpf program attached to the xdp hook.
> Fix the issue defining the skb pointer in the 'budget' loop
> 
> Fixes: ba2b232108d3c ("net: netsec: add XDP support")
> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> ---
>  drivers/net/ethernet/socionext/netsec.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/socionext/netsec.c b/drivers/net/ethernet/socionext/netsec.c
> index 869a498e3b5e..0e12a9856aea 100644
> --- a/drivers/net/ethernet/socionext/netsec.c
> +++ b/drivers/net/ethernet/socionext/netsec.c
> @@ -929,7 +929,6 @@ static int netsec_process_rx(struct netsec_priv *priv, int budget)
>  	struct netsec_rx_pkt_info rx_info;
>  	enum dma_data_direction dma_dir;
>  	struct bpf_prog *xdp_prog;
> -	struct sk_buff *skb = NULL;
>  	u16 xdp_xmit = 0;
>  	u32 xdp_act = 0;
>  	int done = 0;
> @@ -943,6 +942,7 @@ static int netsec_process_rx(struct netsec_priv *priv, int budget)
>  		struct netsec_de *de = dring->vaddr + (DESC_SZ * idx);
>  		struct netsec_desc *desc = &dring->desc[idx];
>  		struct page *page = virt_to_page(desc->addr);
> +		struct sk_buff *skb = NULL;
>  		u32 xdp_result = XDP_PASS;
>  		u16 pkt_len, desc_len;
>  		dma_addr_t dma_handle;
> -- 
> 2.21.1
> 

Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>