| Message ID | 20221219022755.1047573-1-wei.fang@nxp.com (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [V2,net] net: fec: Coverity issue: Dereference null return value | expand |
On Sun, Dec 18, 2022 at 6:31 PM <wei.fang@nxp.com> wrote: > > From: Wei Fang <wei.fang@nxp.com> > > The build_skb might return a null pointer but there is no check on the > return value in the fec_enet_rx_queue(). So a null pointer dereference > might occur. To avoid this, we check the return value of build_skb. If > the return value is a null pointer, the driver will recycle the page and > update the statistic of ndev. Then jump to rx_processing_done to clear > the status flags of the BD so that the hardware can recycle the BD. > > Signed-off-by: Wei Fang <wei.fang@nxp.com> > Reviewed-by: Shenwei Wang <Shenwei.wang@nxp.com> > --- > V2 changes: > 1. Remove rx_packets and rx_bytes counters. > 2. Use netdev_err_once instead of netdev_err. > --- > drivers/net/ethernet/freescale/fec_main.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c > index 5528b0af82ae..644f3c963730 100644 > --- a/drivers/net/ethernet/freescale/fec_main.c > +++ b/drivers/net/ethernet/freescale/fec_main.c > @@ -1674,6 +1674,14 @@ fec_enet_rx_queue(struct net_device *ndev, int budget, u16 queue_id) > * bridging applications. > */ > skb = build_skb(page_address(page), PAGE_SIZE); > + if (unlikely(!skb)) { > + page_pool_recycle_direct(rxq->page_pool, page); > + ndev->stats.rx_dropped++; > + > + netdev_err_once(ndev, "build_skb failed!\n"); > + goto rx_processing_done; > + } > + > skb_reserve(skb, data_start); > skb_put(skb, pkt_len - sub_len); > skb_mark_for_recycle(skb); Looks good to me. Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
On Mon, 19 Dec 2022 10:27:55 +0800 wei.fang@nxp.com wrote: > From: Wei Fang <wei.fang@nxp.com> > > The build_skb might return a null pointer but there is no check on the > return value in the fec_enet_rx_queue(). So a null pointer dereference > might occur. To avoid this, we check the return value of build_skb. If > the return value is a null pointer, the driver will recycle the page and > update the statistic of ndev. Then jump to rx_processing_done to clear > the status flags of the BD so that the hardware can recycle the BD. Applied but I had to change the subject because the subject should describe the change. Mentioning the tool which found the problem belongs in the body of the message.
> -----Original Message----- > From: Jakub Kicinski <kuba@kernel.org> > Sent: 2022年12月21日 3:36 > To: Wei Fang <wei.fang@nxp.com> > Cc: davem@davemloft.net; edumazet@google.com; pabeni@redhat.com; > Clark Wang <xiaoning.wang@nxp.com>; Shenwei Wang > <shenwei.wang@nxp.com>; alexander.duyck@gmail.com; dl-linux-imx > <linux-imx@nxp.com>; netdev@vger.kernel.org; linux-kernel@vger.kernel.org > Subject: Re: [PATCH V2 net] net: fec: Coverity issue: Dereference null return > value > > On Mon, 19 Dec 2022 10:27:55 +0800 wei.fang@nxp.com wrote: > > From: Wei Fang <wei.fang@nxp.com> > > > > The build_skb might return a null pointer but there is no check on the > > return value in the fec_enet_rx_queue(). So a null pointer dereference > > might occur. To avoid this, we check the return value of build_skb. If > > the return value is a null pointer, the driver will recycle the page > > and update the statistic of ndev. Then jump to rx_processing_done to > > clear the status flags of the BD so that the hardware can recycle the BD. > > Applied but I had to change the subject because the subject should describe > the change. Mentioning the tool which found the problem belongs in the body > of the message. Thanks for taking the time to make these changes, I'll keep these things in mind next time.
diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c index 5528b0af82ae..644f3c963730 100644 --- a/drivers/net/ethernet/freescale/fec_main.c +++ b/drivers/net/ethernet/freescale/fec_main.c @@ -1674,6 +1674,14 @@ fec_enet_rx_queue(struct net_device *ndev, int budget, u16 queue_id) * bridging applications. */ skb = build_skb(page_address(page), PAGE_SIZE); + if (unlikely(!skb)) { + page_pool_recycle_direct(rxq->page_pool, page); + ndev->stats.rx_dropped++; + + netdev_err_once(ndev, "build_skb failed!\n"); + goto rx_processing_done; + } + skb_reserve(skb, data_start); skb_put(skb, pkt_len - sub_len); skb_mark_for_recycle(skb);