netdev - Re: [PATCH net] tcp: switch snprintf to scnprintf

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Date:   Mon, 18 Nov 2019 19:48:32 -0800
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     Hangbin Liu <liuhangbin@...il.com>,
        Eric Dumazet <eric.dumazet@...il.com>
Cc:     Jiri Benc <jbenc@...hat.com>, netdev@...r.kernel.org,
        Eric Dumazet <edumazet@...gle.com>,
        "David S . Miller" <davem@...emloft.net>
Subject: Re: [PATCH net] tcp: switch snprintf to scnprintf



On 11/18/19 5:53 PM, Hangbin Liu wrote:
> On Fri, Nov 15, 2019 at 10:54:55AM +0100, Jiri Benc wrote:
>> On Fri, 15 Nov 2019 10:41:06 +0800, Hangbin Liu wrote:
>>>> We need to properly size the output buffers before using them,
>>>> we can not afford truncating silently the output.
>>>
>>> Yes, I agree. Just as I said, the buffer is still enough, while scnprintf
>>> is just a safer usage compired with snprintf.
>>
>> So maybe keep snprintf but add WARN_ON and bail out of the loop if the
>> buffer size was reached?
>>
>> 	if (WARN_ON(offs >= maxlen))
>> 		break;
>>
> 
> Hi Eric,
> 
> What do you think?
> 

WARN_ON_ONCE() please...