Re: [PATCH bpf-next 0/2] bpf: Align syscall writeback behavior with user-declared size

[Alexei Starovoitov]

On Fri, May 15, 2026 at 12:15 AM Yuyang Huang <yuyanghuang@xxxxxxxxxx> wrote:
>
> The bpf(cmd, attr, size) syscall copies up to 'size' bytes on input, but
> several commands write outputs back to userspace unconditionally. If the
> caller passes a short buffer, this can lead to out-of-bounds writes,
> potentially overwriting adjacent userspace memory.

The whole thing sounds like a user space bug.
Please demonstrate a case where this issue is seen
by using libbpf APIs.