From d1a37dedcfcf2c01daff5281c3c378876a04e2f4 Mon Sep 17 00:00:00 2001 From: Yunsheng Lin Date: Thu, 5 Dec 2019 10:12:28 +0800 Subject: [PATCH] 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: 51e8439f3496 ("net: hns3: add 8 BD limit for tx flow") Signed-off-by: Yunsheng Lin Signed-off-by: Huazhong Tan Signed-off-by: David S. Miller --- .../net/ethernet/hisilicon/hns3/hns3_enet.c | 19 ++++++------------- 1 file changed, 6 insertions(+), 13 deletions(-) diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c index e2730319bd43..69545dd6c938 100644 --- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c +++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c @@ -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); -- GitLab