Re: [PATCH] net/sched: cake: reject overhead values that underflow length

[Eric Dumazet]

On Mon, Jun 8, 2026 at 5:06 PM Samuel Moelius
<sam.moelius@xxxxxxxxxxxxxxx> wrote:
>
> CAKE accepts overhead values that can make adjusted packet length
> arithmetic underflow.  A negative effective length can wrap through
> unsigned arithmetic and become a large value.
>
> Such configurations make rate accounting depend on integer wraparound
> rather than on the packet size userspace intended to model.
>
> Validate overhead settings before using them in adjusted length
> calculations.
>
> Assisted-by: Codex:gpt-5.5-cyber-preview
> Signed-off-by: Samuel Moelius <sam.moelius@xxxxxxxxxxxxxxx>
> ---

We need a Fixes: tag

pw-bot: cr