Re: [PATCH] net: ethernet: marvell: sky2.c: Cleaning up missing null-terminate in conjunction with strncpy

[David Miller <davem@davemloft.net>]

From: Stephen Hemminger <stephen@networkplumber.org>
Date: Sun, 14 Sep 2014 19:05:57 -0700

> On Sun, 14 Sep 2014 19:33:43 +0200
> Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se> wrote:
> 
>> Replacing strncpy with strlcpy to avoid strings that lacks null terminate.
>> 
>> Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
>> ---
>>  drivers/net/ethernet/marvell/sky2.c |    2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>> 
>> diff --git a/drivers/net/ethernet/marvell/sky2.c b/drivers/net/ethernet/marvell/sky2.c
>> index dba48a5c..7053d38 100644
>> --- a/drivers/net/ethernet/marvell/sky2.c
>> +++ b/drivers/net/ethernet/marvell/sky2.c
>> @@ -4907,7 +4907,7 @@ static const char *sky2_name(u8 chipid, char *buf, int sz)
>>  	};
>>  
>>  	if (chipid >= CHIP_ID_YUKON_XL && chipid <= CHIP_ID_YUKON_OP_2)
>> -		strncpy(buf, name[chipid - CHIP_ID_YUKON_XL], sz);
>> +		strlcpy(buf, name[chipid - CHIP_ID_YUKON_XL], sz);
>>  	else
>>  		snprintf(buf, sz, "(chip %#x)", chipid);
>>  	return buf;
> 
> Useless and unnecessary since the list of names is right there.
> Why not avoid the copy all together?
> 
> Subject: sky2: avoid strncpy
> 
> Don't use strncpy() since security thought police think it is bad.
> 
> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>

I think providing the buffer on the stack of the thread executing the
probe is superior because it will allow enabling parallel probing
in the future.

I don't think you have to change that aspect to achieve your goal
of returning the const char * string when possible.