Re: [PATCH net v2] net: bgmac: fix oversized RX frame check

[Florian Fainelli]

On 10/27/26 18:10, Rosen Penev wrote:
> While reviewing commit 77dac783f11
> ("net: bgmac: rate limit RX error messages") , Florian spotted that the RX
> length sanity check compares the length reported in the RX header against
> BGMAC_RX_ALLOC_SIZE. That is the size of the whole fragment, including the
> space reserved for struct skb_shared_info. The data area handed to the
> hardware is only BGMAC_RX_BUF_SIZE bytes, and the frame starts
> BGMAC_RX_FRAME_OFFSET bytes into it, so a valid frame is at most
> BGMAC_RX_MAX_FRAME_SIZE bytes long.
>
> A corrupted length between those two limits passes the check, and the
> following skb_put() runs past the skb tailroom and calls
> skb_over_panic() instead of dropping the frame.
>
> Compare against BGMAC_RX_MAX_FRAME_SIZE instead.
>
> Only compile tested. Not tested on hardware.
>
> Fixes: 6a6c708469c9 ("bgmac: add check for oversized packets")
> Signed-off-by: Rosen Penev <rosenp@xxxxxxxxx>

Reviewed-by: Florian Fainelli <florian.fainelli@xxxxxxxxxxxx>
--
Florian