Re: [tipc-discussion] [net-next] tipc: add NULL pointer check

[Ying X. <yin...@wi...>]

On 4/2/19 8:40 PM, Hoang Le wrote:
> skb somehow dequeued out of inputq before processing, it causes to
> NULL pointer and kernel crashed.
> 
> Add checking skb valid before using.
> 
> Fixes: c55c8edafa9 ("tipc: smooth change between replicast and broadcast")
> Reported-by: Tuong Lien Tong <tuo...@de...>
> Signed-off-by: Hoang Le <hoa...@de...>

Acked-by: Ying Xue <yin...@wi...>

> ---
>  net/tipc/bcast.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/net/tipc/bcast.c b/net/tipc/bcast.c
> index 76e14dc08bb9..6c997d4a6218 100644
> --- a/net/tipc/bcast.c
> +++ b/net/tipc/bcast.c
> @@ -769,6 +769,9 @@ void tipc_mcast_filter_msg(struct net *net, struct sk_buff_head *defq,
>  	u32 node, port;
>  
>  	skb = skb_peek(inputq);
> +	if (!skb)
> +		return;
> +
>  	hdr = buf_msg(skb);
>  
>  	if (likely(!msg_is_syn(hdr) && skb_queue_empty(defq)))
>