Re: [PATCH net v2] net/sched: cake: reject overhead values that underflow length

[Toke Høiland-Jørgensen]

Samuel Moelius <sam.moelius@xxxxxxxxxxxxxxx> writes:

> 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.
>
> Fixes: a729b7f0bd5b ("sch_cake: Add overhead compensation support to the rate shaper")
> Assisted-by: Codex:gpt-5.5-cyber-preview
> Signed-off-by: Samuel Moelius <sam.moelius@xxxxxxxxxxxxxxx>

Acked-by: Toke Høiland-Jørgensen <toke@xxxxxxx>