Re: [PATCH net v7 2/2] selftests: net: add TAP socket filter attach tests

[Willem de Bruijn <willemdebruijn.kernel@gmail.com>]

Rongguang Wei wrote:
> From: Rongguang Wei <weirongguang@kylinos.cn>
> 
> reattach_filter_without_user_buffer() attaches a filter, makes the buffer
> the program was copied from unreadable, detaches the queue and attaches it
> again. It then attaches a second queue from a fresh socket, which starts
> without a filter of its own, so a clear IFF_NOFILTER shows that the filter
> was installed again from the kernel copy.
> 
> attach_filter_bad_len_keeps_program() checks that a TUNATTACHFILTER with a
> bad length leaves the installed program and the filter state that
> TUNGETIFF reports alone, and that a queue attached afterwards still gets
> the filter.  attach_filter_bad_prog_keeps_program() refuses a program with
> a valid length and instructions that bpf_check_classic() rejects, and
> checks that the program installed before is left in place.
> 
> attach_filter_nofilter_flag() and detach_filter_clears_reattach() cover the
> ways to attach a queue without a filter.
> 
> Signed-off-by: Rongguang Wei <weirongguang@kylinos.cn>

Reviewed-by: Willem de Bruijn <willemb@google.com>