Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Mon, 5 Dec 2022 09:43:20 +0100 | Subject | Re: [PATCH net] ravb: Fix potential use-after-free in ravb_rx_gbeth() |
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Hi Biju,
On Sat, Dec 3, 2022 at 11:29 AM Biju Das <biju.das.jz@bp.renesas.com> wrote: > > Subject: [PATCH net] ravb: Fix potential use-after-free in > > ravb_rx_gbeth() > > > > The skb is delivered to napi_gro_receive() which may free it, after > > calling this, dereferencing skb may trigger use-after-free. > > Can you please reconfirm the changes you have done is actually fixing any issue? > If yes, please provide the details. > > Current code, > > napi_gro_receive(&priv->napi[q], priv->rx_1st_skb);
IIUIC, after this, priv->rx_1st_skb may have been freed...
> > - stats->rx_bytes += priv->rx_1st_skb->len;
... so accessing priv->rx_1st_skb->len here may be a UAF.
> + stats->rx_bytes += pkt_len;
So this change looks correct to me, as pkt_len was stored to priv->rx_1st_skb->len using skb_put() before.
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
> > Note: I haven't tested your patch yet to see it cause any regression. > > Cheers, > Biju > > > > > Fixes: 1c59eb678cbd ("ravb: Fillup ravb_rx_gbeth() stub") > > Signed-off-by: YueHaibing <yuehaibing@huawei.com> > > --- > > drivers/net/ethernet/renesas/ravb_main.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/net/ethernet/renesas/ravb_main.c > > b/drivers/net/ethernet/renesas/ravb_main.c > > index 6bc923326268..33f723a9f471 100644 > > --- a/drivers/net/ethernet/renesas/ravb_main.c > > +++ b/drivers/net/ethernet/renesas/ravb_main.c > > @@ -841,7 +841,7 @@ static bool ravb_rx_gbeth(struct net_device *ndev, > > int *quota, int q) > > napi_gro_receive(&priv->napi[q], > > priv->rx_1st_skb); > > stats->rx_packets++; > > - stats->rx_bytes += priv->rx_1st_skb->len; > > + stats->rx_bytes += pkt_len; > > break; > > } > > }
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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