Commit d1a37ded authored by Yunsheng Lin's avatar Yunsheng Lin Committed by David S. Miller
Browse files

net: hns3: fix a use after free problem in hns3_nic_maybe_stop_tx() 



Currently, hns3_nic_maybe_stop_tx() uses skb_copy() to linearize a
SKB if the BD num required by the SKB does not meet the hardware
limitation, and it linearizes the SKB by allocating a new linearized SKB
and freeing the old SKB, if hns3_nic_maybe_stop_tx() returns -EBUSY
because there are no enough space in the ring to send the linearized
skb to hardware, the sch_direct_xmit() still hold reference to old SKB
and try to retransmit the old SKB when dev_hard_start_xmit() return
TX_BUSY, which may cause use after freed problem.

This patch fixes it by using __skb_linearize() to linearize the
SKB in hns3_nic_maybe_stop_tx().

Fixes: 51e8439f ("net: hns3: add 8 BD limit for tx flow")
Signed-off-by: default avatarYunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: default avatarHuazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2a597eff

drivers/net/ethernet/hisilicon/hns3/hns3_enet.c

+6 −13
Original line number Diff line number Diff line
@@ -1288,31 +1288,24 @@ static bool hns3_skb_need_linearized(struct sk_buff *skb, unsigned int *bd_size, 


static int hns3_nic_maybe_stop_tx(struct hns3_enet_ring *ring,

				  struct net_device *netdev,

				  struct sk_buff **out_skb)

				  struct sk_buff *skb)

{

	struct hns3_nic_priv *priv = netdev_priv(netdev);

	unsigned int bd_size[HNS3_MAX_TSO_BD_NUM + 1U];

	struct sk_buff *skb = *out_skb;

	unsigned int bd_num;



	bd_num = hns3_tx_bd_num(skb, bd_size);

	if (unlikely(bd_num > HNS3_MAX_NON_TSO_BD_NUM)) {

		struct sk_buff *new_skb;



		if (bd_num <= HNS3_MAX_TSO_BD_NUM && skb_is_gso(skb) &&

		    !hns3_skb_need_linearized(skb, bd_size, bd_num))

			goto out;



		/* manual split the send packet */

		new_skb = skb_copy(skb, GFP_ATOMIC);

		if (!new_skb)

		if (__skb_linearize(skb))

			return -ENOMEM;

		dev_kfree_skb_any(skb);

		*out_skb = new_skb;



		bd_num = hns3_tx_bd_count(new_skb->len);

		if ((skb_is_gso(new_skb) && bd_num > HNS3_MAX_TSO_BD_NUM) ||

		    (!skb_is_gso(new_skb) &&

		bd_num = hns3_tx_bd_count(skb->len);

		if ((skb_is_gso(skb) && bd_num > HNS3_MAX_TSO_BD_NUM) ||

		    (!skb_is_gso(skb) &&

		     bd_num > HNS3_MAX_NON_TSO_BD_NUM))

			return -ENOMEM;
@@ -1415,7 +1408,7 @@ netdev_tx_t hns3_nic_net_xmit(struct sk_buff *skb, struct net_device *netdev) 
	/* Prefetch the data used later */

	prefetch(skb->data);



	ret = hns3_nic_maybe_stop_tx(ring, netdev, &skb);

	ret = hns3_nic_maybe_stop_tx(ring, netdev, skb);

	if (unlikely(ret <= 0)) {

		if (ret == -EBUSY) {

			u64_stats_update_begin(&ring->syncp);

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