Re: [PATCH net-next v3 5/6] netlink: specs: rt-route: describe lwt BPF program options

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] netlink: missing max-len validation constraint for string attribute
--

commit f56da32d0f53d2458e2f20c65435e7f6e11b64a4
Author: Hangbin Liu <liuhangbin@kylinos.cn>

netlink: specs: rt-route: describe lwt BPF program options

This patch replaces binary BPF attributes with a nested lwt-bpf-prog to
support lwt bpf prog options in the rt-route netlink specification.

> diff --git a/Documentation/netlink/specs/rt-route.yaml b/Documentation/netlink/specs/rt-route.yaml
> index 7649797602eb7..afec0375661f5 100644
> --- a/Documentation/netlink/specs/rt-route.yaml
> +++ b/Documentation/netlink/specs/rt-route.yaml
[ ... ]
> @@ -621,6 +624,16 @@ attribute-sets:
>        -
>          name: hwid
>          type: u8
> +  -
> +    name: lwt-bpf-prog
> +    name-prefix: lwt-bpf-prog-
> +    attributes:
> +      -
> +        name: fd
> +        type: u32
> +      -
> +        name: name
> +        type: string

[Severity: Low]
Does this string attribute need a maximum length validation constraint?

The kernel's LWT_BPF_PROG_NAME policy restricts the length to MAX_PROG_NAME
(which is 256). For netlink string specifications, this usually means adding
a checks section with max-len: 255.

Without this declarative constraint, the generated userspace tooling will not
restrict the string length prior to constructing the netlink message, forcing
the kernel to reject over-sized strings. This bypasses client-side validation.

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Sashiko AI review · https://sashiko.dev/#/patchset/20260930-ynl_rt_encap-v3-0-4106c21b9ee7@kylinos.cn?part=5