Subject: Re: [PATCH net-next v2] net/rds: use strscpy() to instead of strncpy()

From: Jakub Kicinski <[email-masked]>
Date: Thu, 12 Jan 2023 21:17:07 -0800

On Wed, 11 Jan 2023 14:25:48 +0800 (CST) [email-masked] wrote:
> From: Xu Panda <[email-masked]>
> 
> The implementation of strscpy() is more robust and safer.
> That's now the recommended way to copy NUL-terminated strings.

What are the differences in behavior between strncpy() and strscpy()?

> diff --git a/net/rds/stats.c b/net/rds/stats.c
> index 9e87da43c004..7018c67418f5 100644
> --- a/net/rds/stats.c
> +++ b/net/rds/stats.c
> @@ -88,9 +88,7 @@ void rds_stats_info_copy(struct rds_info_iterator *iter,
>  	size_t i;
> 
>  	for (i = 0; i < nr; i++) {
> -		BUG_ON(strlen(names[i]) >= sizeof(ctr.name));
> -		strncpy(ctr.name, names[i], sizeof(ctr.name) - 1);
> -		ctr.name[sizeof(ctr.name) - 1] = '\0';
> +		BUG_ON(strscpy(ctr.name, names[i], sizeof(ctr.name)) < 0);
>  		ctr.value = values[i];
> 
>  		rds_info_copy(iter, &ctr, sizeof(ctr));