Commit 643001b4 authored by Lv Yunlong's avatar Lv Yunlong Committed by David S. Miller
Browse files

ethernet:enic: Fix a use after free bug in enic_hard_start_xmit 

In enic_hard_start_xmit, it calls enic_queue_wq_skb(). Inside
enic_queue_wq_skb, if some error happens, the skb will be freed
by dev_kfree_skb(skb). But the freed skb is still used in
skb_tx_timestamp(skb).

My patch makes enic_queue_wq_skb() return error and goto spin_unlock()
incase of error. The solution is provided by Govind.
See https://lkml.org/lkml/2021/4/30/961

.

Fixes: fb7516d4 ("enic: add sw timestamp support")
Signed-off-by: default avatarLv Yunlong <lyl2019@mail.ustc.edu.cn>
Acked-by: default avatarGovindarajulu Varadarajan <gvaradar@cisco.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f18c51b6

drivers/net/ethernet/cisco/enic/enic_main.c

+5 −2
Original line number Diff line number Diff line
@@ -768,7 +768,7 @@ static inline int enic_queue_wq_skb_encap(struct enic *enic, struct vnic_wq *wq, 
	return err;

}



static inline void enic_queue_wq_skb(struct enic *enic,

static inline int enic_queue_wq_skb(struct enic *enic,

	struct vnic_wq *wq, struct sk_buff *skb)

{

	unsigned int mss = skb_shinfo(skb)->gso_size;
@@ -814,6 +814,7 @@ static inline void enic_queue_wq_skb(struct enic *enic, 
		wq->to_use = buf->next;

		dev_kfree_skb(skb);

	}

	return err;

}



/* netif_tx_lock held, process context with BHs disabled, or BH */
@@ -857,7 +858,8 @@ static netdev_tx_t enic_hard_start_xmit(struct sk_buff *skb, 
		return NETDEV_TX_BUSY;

	}



	enic_queue_wq_skb(enic, wq, skb);

	if (enic_queue_wq_skb(enic, wq, skb))

		goto error;



	if (vnic_wq_desc_avail(wq) < MAX_SKB_FRAGS + ENIC_DESC_MAX_SPLITS)

		netif_tx_stop_queue(txq);
@@ -865,6 +867,7 @@ static netdev_tx_t enic_hard_start_xmit(struct sk_buff *skb, 
	if (!netdev_xmit_more() || netif_xmit_stopped(txq))

		vnic_wq_doorbell(wq);



error:

	spin_unlock(&enic->wq_lock[txq_map]);



	return NETDEV_TX_OK;