netdev - 答复: [PATCH] ping: Check return value of function 'ping_queue_rcv

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Date:   Tue, 8 Jun 2021 01:48:05 +0000
From:   zhengyongjun <zhengyongjun3@...wei.com>
To:     David Ahern <dsahern@...il.com>,
        "davem@...emloft.net" <davem@...emloft.net>,
        "yoshfuji@...ux-ipv6.org" <yoshfuji@...ux-ipv6.org>,
        "dsahern@...nel.org" <dsahern@...nel.org>,
        "kuba@...nel.org" <kuba@...nel.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: 答复: [PATCH] ping: Check return value of function 'ping_queue_rcv_skb'

Thank you for your suggestion, it will make the code look cleaner :) 
I will send patch v2 soon.

-----邮件原件-----
发件人: David Ahern [mailto:dsahern@...il.com] 
发送时间: 2021年6月8日 0:26
收件人: zhengyongjun <zhengyongjun3@...wei.com>; davem@...emloft.net; yoshfuji@...ux-ipv6.org; dsahern@...nel.org; kuba@...nel.org; netdev@...r.kernel.org; linux-kernel@...r.kernel.org
主题: Re: [PATCH] ping: Check return value of function 'ping_queue_rcv_skb'

On 6/7/21 3:10 AM, 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@...wei.com>
> ---
>  net/ipv4/ping.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c index 
> 1c9f71a37258..8e84cde95011 100644
> --- a/net/ipv4/ping.c
> +++ b/net/ipv4/ping.c
> @@ -968,10 +968,11 @@ bool ping_rcv(struct sk_buff *skb)
>  		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)) {
> +			sock_put(sk);
> +			return true;
> +		}
>  		sock_put(sk);
> -		return true;
>  	}
>  	pr_debug("no socket, dropping\n");
>  
> 

declare a default return variable:

	bool rc = false;

set to to true if ping_queue_rcv_skb() fails and have one exit path with one sock_put.