linux-kernel - Re: [PATCH linux-next] kernfs: use strscpy() is more robust and safer

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Message-ID: <Y3M0+fNWo+lrEPZw@kroah.com>
Date:   Tue, 15 Nov 2022 07:43:05 +0100
From:   Greg KH <gregkh@...uxfoundation.org>
To:     guo.ziliang@....com.cn
Cc:     tj@...nel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH linux-next] kernfs: use strscpy() is more robust and safer

On Tue, Nov 15, 2022 at 08:47:45AM +0800, guo.ziliang@....com.cn wrote:
> From: guo ziliang <guo.ziliang@....com.cn>
> 
> The implementation of strscpy() is more robust and safer.

How exactly is it more robust and safer?

> That's now the recommended way to copy NUL terminated strings.

Recommended by whom for what?



> 
> Signed-off-by: guo ziliang <guo.ziliang@....com.cn>
> ---
>  fs/kernfs/dir.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
> index 77d7a3a..fbb8df4 100644
> --- a/fs/kernfs/dir.c
> +++ b/fs/kernfs/dir.c
> @@ -844,7 +844,7 @@ static struct kernfs_node *kernfs_walk_ns(struct kernfs_node *parent,
> 
>         spin_lock_irq(&kernfs_pr_cont_lock);
> 
> -       len = strlcpy(kernfs_pr_cont_buf, path, sizeof(kernfs_pr_cont_buf));
> +       len = strscpy(kernfs_pr_cont_buf, path, sizeof(kernfs_pr_cont_buf));

How did you test this change is correct and does not cause any problems?

How was this issue found?

thanks,

greg k-h