linux-kernel - Re: [PATCH linux-next v2] parisc: use strscpy() to instead of strncpy()

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Date:   Tue, 27 Dec 2022 22:30:35 +0100
From:   Helge Deller <deller@....de>
To:     Rolf Eike Beer <eike-kernel@...tec.de>,
        james.bottomley@...senpartnership.com, yang.yang29@....com.cn
Cc:     linux-parisc@...r.kernel.org, linux-kernel@...r.kernel.org,
        xu.panda@....com.cn
Subject: Re: [PATCH linux-next v2] parisc: use strscpy() to instead of
 strncpy()

On 12/27/22 08:47, Rolf Eike Beer wrote:
> Am Montag, 26. Dezember 2022, 11:40:04 CET schrieb yang.yang29@....com.cn:
>> From: Xu Panda <xu.panda@....com.cn>
>>
>> The implementation of strscpy() is more robust and safer.
>> That's now the recommended way to copy NUL-terminated strings.
>>
>> Signed-off-by: Xu Panda <xu.panda@....com.cn>
>> Signed-off-by: Yang Yang <yang.yang29@....com>
>> ---
>> change for v2
>>   - sizeof(in) is better and simplified, thanks for Helge Deller.
>> ---
>>   drivers/parisc/pdc_stable.c | 9 +++------
>>   1 file changed, 3 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/parisc/pdc_stable.c b/drivers/parisc/pdc_stable.c
>> index d6af5726ddf3..d3075445260b 100644
>> --- a/drivers/parisc/pdc_stable.c
>> +++ b/drivers/parisc/pdc_stable.c
>> @@ -274,8 +274,7 @@ pdcspath_hwpath_write(struct pdcspath_entry *entry,
>> const char *buf, size_t coun
>>
>>   	/* We'll use a local copy of buf */
>>   	count = min_t(size_t, count, sizeof(in)-1);
>> -	strncpy(in, buf, count);
>> -	in[count] = '\0';
>> +	strscpy(in, buf, sizeof(in));
>
> What is "count" now needed for? Looks like a write only variable at least in
> these hunks.

isn't count the return value?

Helge