diff mbox series

[net-next,4/6] net: sparx5: move SKB consumption to xmit()

Message ID 20250109-sparx5-lan969x-switch-driver-5-v1-4-13d6d8451e63@microchip.com (mailing list archive)
State New
Headers show
Series net: lan969x: add FDMA support | expand

Commit Message

Daniel Machon Jan. 9, 2025, 6:37 p.m. UTC 
Currently, SKB's are consumed in sparx5_port_xmit_impl(), if the FDMA
xmit() function returns NETDEV_TX_OK. In a following commit, we will ops
out the xmit() function for lan969x support, and since lan969x is going
to consume SKB's asynchronously, in the NAPI poll loop, we cannot
consume SKB's in sparx5_port_xmit_impl() anymore. Therefore, move the
call of dev_consume_skb_any() to the xmit() function.

Reviewed-by: Steen Hegelund <Steen.Hegelund@microchip.com>
Signed-off-by: Daniel Machon <daniel.machon@microchip.com>
---
 drivers/net/ethernet/microchip/sparx5/sparx5_fdma.c   | 2 ++
 drivers/net/ethernet/microchip/sparx5/sparx5_packet.c | 1 -
 2 files changed, 2 insertions(+), 1 deletion(-)

Comments

Eric Dumazet Jan. 9, 2025, 7:13 p.m. UTC | #1 
On Thu, Jan 9, 2025 at 7:38 PM Daniel Machon
<daniel.machon@microchip.com> wrote:
>
> Currently, SKB's are consumed in sparx5_port_xmit_impl(), if the FDMA
> xmit() function returns NETDEV_TX_OK. In a following commit, we will ops
> out the xmit() function for lan969x support, and since lan969x is going
> to consume SKB's asynchronously, in the NAPI poll loop, we cannot
> consume SKB's in sparx5_port_xmit_impl() anymore. Therefore, move the
> call of dev_consume_skb_any() to the xmit() function.
>
> Reviewed-by: Steen Hegelund <Steen.Hegelund@microchip.com>
> Signed-off-by: Daniel Machon <daniel.machon@microchip.com>
> ---
>  drivers/net/ethernet/microchip/sparx5/sparx5_fdma.c   | 2 ++
>  drivers/net/ethernet/microchip/sparx5/sparx5_packet.c | 1 -
>  2 files changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/microchip/sparx5/sparx5_fdma.c b/drivers/net/ethernet/microchip/sparx5/sparx5_fdma.c
> index fdae62f557ce..cb78acd356d2 100644
> --- a/drivers/net/ethernet/microchip/sparx5/sparx5_fdma.c
> +++ b/drivers/net/ethernet/microchip/sparx5/sparx5_fdma.c
> @@ -239,6 +239,8 @@ int sparx5_fdma_xmit(struct sparx5 *sparx5, u32 *ifh, struct sk_buff *skb)
>
>         sparx5_fdma_reload(sparx5, fdma);
>
> +       dev_consume_skb_any(skb);
> +
>         return NETDEV_TX_OK;
>  }
>
> diff --git a/drivers/net/ethernet/microchip/sparx5/sparx5_packet.c b/drivers/net/ethernet/microchip/sparx5/sparx5_packet.c
> index b6f635d85820..e776fa0845c6 100644
> --- a/drivers/net/ethernet/microchip/sparx5/sparx5_packet.c
> +++ b/drivers/net/ethernet/microchip/sparx5/sparx5_packet.c
> @@ -272,7 +272,6 @@ netdev_tx_t sparx5_port_xmit_impl(struct sk_buff *skb, struct net_device *dev)
>             SPARX5_SKB_CB(skb)->rew_op == IFH_REW_OP_TWO_STEP_PTP)
>                 return NETDEV_TX_OK;

If packet is freed earlier in sparx5_fdma_xmit(), you have UAF few
lines above here ..

stats->tx_bytes += skb->len; // UAF
...
if (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP &&   // UAF
SPARX5_SKB_CB(skb)->rew_op == IFH_REW_OP_TWO_STEP_PTP)   // UAF


>
> -       dev_consume_skb_any(skb);
>         return NETDEV_TX_OK;
>  drop:
>         stats->tx_dropped++;
>
> --
> 2.34.1
>
Daniel Machon Jan. 10, 2025, 9:29 a.m. UTC | #2 
Hi Eric,

> > diff --git a/drivers/net/ethernet/microchip/sparx5/sparx5_packet.c b/drivers/net/ethernet/microchip/sparx5/sparx5_packet.c
> > index b6f635d85820..e776fa0845c6 100644
> > --- a/drivers/net/ethernet/microchip/sparx5/sparx5_packet.c
> > +++ b/drivers/net/ethernet/microchip/sparx5/sparx5_packet.c
> > @@ -272,7 +272,6 @@ netdev_tx_t sparx5_port_xmit_impl(struct sk_buff *skb, struct net_device *dev)
> >             SPARX5_SKB_CB(skb)->rew_op == IFH_REW_OP_TWO_STEP_PTP)
> >                 return NETDEV_TX_OK;
> 
> If packet is freed earlier in sparx5_fdma_xmit(), you have UAF few
> lines above here ..
> 
> stats->tx_bytes += skb->len; // UAF
> ...
> if (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP &&   // UAF
> SPARX5_SKB_CB(skb)->rew_op == IFH_REW_OP_TWO_STEP_PTP)   // UAF
> 

Yes, this needs to be done differently. I will rework the SKB consumption in
v2. Thanks a lot!

/Daniel
diff mbox series

Patch

diff --git a/drivers/net/ethernet/microchip/sparx5/sparx5_fdma.c b/drivers/net/ethernet/microchip/sparx5/sparx5_fdma.c
index fdae62f557ce..cb78acd356d2 100644
--- a/drivers/net/ethernet/microchip/sparx5/sparx5_fdma.c
+++ b/drivers/net/ethernet/microchip/sparx5/sparx5_fdma.c
@@ -239,6 +239,8 @@  int sparx5_fdma_xmit(struct sparx5 *sparx5, u32 *ifh, struct sk_buff *skb)
 
 	sparx5_fdma_reload(sparx5, fdma);
 
+	dev_consume_skb_any(skb);
+
 	return NETDEV_TX_OK;
 }
 
diff --git a/drivers/net/ethernet/microchip/sparx5/sparx5_packet.c b/drivers/net/ethernet/microchip/sparx5/sparx5_packet.c
index b6f635d85820..e776fa0845c6 100644
--- a/drivers/net/ethernet/microchip/sparx5/sparx5_packet.c
+++ b/drivers/net/ethernet/microchip/sparx5/sparx5_packet.c
@@ -272,7 +272,6 @@  netdev_tx_t sparx5_port_xmit_impl(struct sk_buff *skb, struct net_device *dev)
 	    SPARX5_SKB_CB(skb)->rew_op == IFH_REW_OP_TWO_STEP_PTP)
 		return NETDEV_TX_OK;
 
-	dev_consume_skb_any(skb);
 	return NETDEV_TX_OK;
 drop:
 	stats->tx_dropped++;