答复: [PATCH v3] ping: Check return value of function 'ping_queue_rcv_skb'

[zhengyongjun]

Thanks for your suggest, I send patch v4 now :)

-----邮件原件-----
发件人: Leon Romanovsky [mailto:leon@xxxxxxxxxx] 
发送时间: 2021年6月8日 14:08
收件人: zhengyongjun <zhengyongjun3@xxxxxxxxxx>
抄送: davem@xxxxxxxxxxxxx; yoshfuji@xxxxxxxxxxxxxx; dsahern@xxxxxxxxxx; kuba@xxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
主题: Re: [PATCH v3] ping: Check return value of function 'ping_queue_rcv_skb'

On Tue, Jun 08, 2021 at 10:08:53AM +0800, Zheng Yongjun wrote:
> Function 'ping_queue_rcv_skb' not always return success, which will 
> also return fail. If not check the wrong return value of it, lead to 
> function `ping_rcv` return success.
> 
> Signed-off-by: Zheng Yongjun <zhengyongjun3@xxxxxxxxxx>
> ---
> v2:
> - use rc as return value to make code look cleaner
> v3:
> - delete unnecessary braces {}
>  net/ipv4/ping.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c index 
> 1c9f71a37258..af9da2f7dc85 100644
> --- a/net/ipv4/ping.c
> +++ b/net/ipv4/ping.c
> @@ -963,19 +963,19 @@ bool ping_rcv(struct sk_buff *skb)
>  	/* Push ICMP header back */
>  	skb_push(skb, skb->data - (u8 *)icmph);
>  
> +	bool rc = false;

Declaration of new variables in the middle of function is C++, while the kernel is written in C. Please put variable declaration at the beginning of function.

Thanks

>  	sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id));
>  	if (sk) {
>  		struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
>  
>  		pr_debug("rcv on socket %p\n", sk);
> -		if (skb2)
> -			ping_queue_rcv_skb(sk, skb2);
> +		if (skb2 && !ping_queue_rcv_skb(sk, skb2))
> +			rc = true;
>  		sock_put(sk);
> -		return true;
>  	}
>  	pr_debug("no socket, dropping\n");
>  
> -	return false;
> +	return rc;
>  }
>  EXPORT_SYMBOL_GPL(ping_rcv);
>  
> --
> 2.25.1
>