Re: [PATCH v3 4/4] mm: huge_memory: Use strscpy() instead of strcpy()

[Barry Song <baohua@kernel.org>]

On Thu, Oct 31, 2024 at 2:03 AM Maíra Canal <mcanal@igalia.com> wrote:
>
> Replace strcpy() with strscpy() in mm/huge_memory.c
>
> strcpy() has been deprecated because it is generally unsafe, so help to
> eliminate it from the kernel source.
>
> Link: https://github.com/KSPP/linux/issues/88
> Signed-off-by: Maíra Canal <mcanal@igalia.com>
> ---
>  mm/huge_memory.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index f92068864469..8f41a694433c 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -989,7 +989,7 @@ static int __init setup_thp_anon(char *str)
>
>         if (!str || strlen(str) + 1 > PAGE_SIZE)
>                 goto err;
> -       strcpy(str_dup, str);
> +       strscpy(str_dup, str);

What is the difference between strcpy and strscpy without a size parameter?

we have already a check and goto err. strcpy() is entirely safe.
         if (!str || strlen(str) + 1 > PAGE_SIZE)
                 goto err;

My understanding is that we don't need this patch.

>
>         always = huge_anon_orders_always;
>         madvise = huge_anon_orders_madvise;
> @@ -4175,7 +4175,7 @@ static ssize_t split_huge_pages_write(struct file *file, const char __user *buf,
>
>                 tok = strsep(&buf, ",");
>                 if (tok) {
> -                       strcpy(file_path, tok);
> +                       strscpy(file_path, tok);
>                 } else {
>                         ret = -EINVAL;
>                         goto out;
> --
> 2.46.2
>

Thanks
barry