Commit 6d72e7c7 authored by Lv Yunlong's avatar Lv Yunlong Committed by David S. Miller
Browse files

net:emac/emac-mac: Fix a use after free in emac_mac_tx_buf_send 



In emac_mac_tx_buf_send, it calls emac_tx_fill_tpd(..,skb,..).
If some error happens in emac_tx_fill_tpd(), the skb will be freed via
dev_kfree_skb(skb) in error branch of emac_tx_fill_tpd().
But the freed skb is still used via skb->len by netdev_sent_queue(,skb->len).

As i observed that emac_tx_fill_tpd() haven't modified the value of skb->len,
thus my patch assigns skb->len to 'len' before the possible free and
use 'len' instead of skb->len later.

Fixes: b9b17deb ("net: emac: emac gigabit ethernet controller driver")
Signed-off-by: default avatarLv Yunlong <lyl2019@mail.ustc.edu.cn>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f77bd544

drivers/net/ethernet/qualcomm/emac/emac-mac.c

+3 −1
Original line number Diff line number Diff line
@@ -1437,6 +1437,7 @@ netdev_tx_t emac_mac_tx_buf_send(struct emac_adapter *adpt, 
{

	struct emac_tpd tpd;

	u32 prod_idx;

	int len;



	memset(&tpd, 0, sizeof(tpd));
@@ -1456,9 +1457,10 @@ netdev_tx_t emac_mac_tx_buf_send(struct emac_adapter *adpt, 
	if (skb_network_offset(skb) != ETH_HLEN)

		TPD_TYP_SET(&tpd, 1);



	len = skb->len;

	emac_tx_fill_tpd(adpt, tx_q, skb, &tpd);



	netdev_sent_queue(adpt->netdev, skb->len);

	netdev_sent_queue(adpt->netdev, len);



	/* Make sure the are enough free descriptors to hold one

	 * maximum-sized SKB.  We need one desc for each fragment,