2022-03-05 20:31:16

by Aleksander Jan Bajkowski

Subject: [PATCH net] net: lantiq_xrx200: fix use after free bug

The skb->len field is read after the packet is sent to the network
stack. In the meantime, skb can be freed. This patch fixes this bug.

Fixes: c3e6b2c35b34 ("net: lantiq_xrx200: add ingress SG DMA support")
Reported-by: Eric Dumazet <[email protected]>
Signed-off-by: Aleksander Jan Bajkowski <[email protected]>
---
drivers/net/ethernet/lantiq_xrx200.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/lantiq_xrx200.c b/drivers/net/ethernet/lantiq_xrx200.c
index 41d11137cde0..5712c3e94be8 100644
--- a/drivers/net/ethernet/lantiq_xrx200.c
+++ b/drivers/net/ethernet/lantiq_xrx200.c
@@ -260,9 +260,9 @@ static int xrx200_hw_receive(struct xrx200_chan *ch)

if (ctl & LTQ_DMA_EOP) {
ch->skb_head->protocol = eth_type_trans(ch->skb_head, net_dev);
- netif_receive_skb(ch->skb_head);
net_dev->stats.rx_packets++;
net_dev->stats.rx_bytes += ch->skb_head->len;
+ netif_receive_skb(ch->skb_head);
ch->skb_head = NULL;
ch->skb_tail = NULL;
ret = XRX200_DMA_PACKET_COMPLETE;
--
2.30.2

2022-03-06 14:23:39

by Hauke Mehrtens

Subject: Re: [PATCH net] net: lantiq_xrx200: fix use after free bug

On 3/5/22 12:20, Aleksander Jan Bajkowski wrote:
> The skb->len field is read after the packet is sent to the network
> stack. In the meantime, skb can be freed. This patch fixes this bug.
>
> Fixes: c3e6b2c35b34 ("net: lantiq_xrx200: add ingress SG DMA support")
> Reported-by: Eric Dumazet <[email protected]>
> Signed-off-by: Aleksander Jan Bajkowski <[email protected]>

Acked-by: Hauke Mehrtens <[email protected]>

> ---
> drivers/net/ethernet/lantiq_xrx200.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/lantiq_xrx200.c b/drivers/net/ethernet/lantiq_xrx200.c
> index 41d11137cde0..5712c3e94be8 100644
> --- a/drivers/net/ethernet/lantiq_xrx200.c
> +++ b/drivers/net/ethernet/lantiq_xrx200.c
> @@ -260,9 +260,9 @@ static int xrx200_hw_receive(struct xrx200_chan *ch)
>
> if (ctl & LTQ_DMA_EOP) {
> ch->skb_head->protocol = eth_type_trans(ch->skb_head, net_dev);
> - netif_receive_skb(ch->skb_head);
> net_dev->stats.rx_packets++;
> net_dev->stats.rx_bytes += ch->skb_head->len;
> + netif_receive_skb(ch->skb_head);
> ch->skb_head = NULL;
> ch->skb_tail = NULL;
> ret = XRX200_DMA_PACKET_COMPLETE;

2022-03-09 01:25:44

by patchwork-bot+netdevbpf

Subject: Re: [PATCH net] net: lantiq_xrx200: fix use after free bug

Hello:

This patch was applied to netdev/net.git (master)
by David S. Miller <[email protected]>:

On Sat, 5 Mar 2022 12:20:39 +0100 you wrote:
> The skb->len field is read after the packet is sent to the network
> stack. In the meantime, skb can be freed. This patch fixes this bug.
>
> Fixes: c3e6b2c35b34 ("net: lantiq_xrx200: add ingress SG DMA support")
> Reported-by: Eric Dumazet <[email protected]>
> Signed-off-by: Aleksander Jan Bajkowski <[email protected]>
>
> [...]

Here is the summary with links:
- [net] net: lantiq_xrx200: fix use after free bug
https://git.kernel.org/netdev/net/c/dd830aed23c6

You are awesome, thank you!
--
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