On Wed, Jun 28, 2023 at 4:53 AM Yafang Shao <laoar.shao@xxxxxxxxx> wrote:
>
> Add a common helper bpf_copy_to_user(), which will be used at multiple
> places.
> No functional change.
>
> Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
> ---
> kernel/bpf/syscall.c | 34 ++++++++++++++++++++--------------
> 1 file changed, 20 insertions(+), 14 deletions(-)
>
Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
> index a2aef900519c..4aa6e5776a04 100644
> --- a/kernel/bpf/syscall.c
> +++ b/kernel/bpf/syscall.c
> @@ -3295,6 +3295,25 @@ static void bpf_raw_tp_link_show_fdinfo(const struct bpf_link *link,
> raw_tp_link->btp->tp->name);
> }
>
> +static int bpf_copy_to_user(char __user *ubuf, const char *buf, u32 ulen,
> + u32 len)
> +{
> + if (ulen >= len + 1) {
> + if (copy_to_user(ubuf, buf, len + 1))
> + return -EFAULT;
> + } else {
> + char zero = '\0';
> +
> + if (copy_to_user(ubuf, buf, ulen - 1))
> + return -EFAULT;
> + if (put_user(zero, ubuf + ulen - 1))
> + return -EFAULT;
> + return -ENOSPC;
> + }
> +
> + return 0;
> +}
> +
> static int bpf_raw_tp_link_fill_link_info(const struct bpf_link *link,
> struct bpf_link_info *info)
> {
> @@ -3313,20 +3332,7 @@ static int bpf_raw_tp_link_fill_link_info(const struct bpf_link *link,
> if (!ubuf)
> return 0;
>
> - if (ulen >= tp_len + 1) {
> - if (copy_to_user(ubuf, tp_name, tp_len + 1))
> - return -EFAULT;
> - } else {
> - char zero = '\0';
> -
> - if (copy_to_user(ubuf, tp_name, ulen - 1))
> - return -EFAULT;
> - if (put_user(zero, ubuf + ulen - 1))
> - return -EFAULT;
> - return -ENOSPC;
> - }
> -
> - return 0;
> + return bpf_copy_to_user(ubuf, tp_name, ulen, tp_len);
> }
>
> static const struct bpf_link_ops bpf_raw_tp_link_lops = {
> --
> 2.39.3
>
