| From c0098d91404149fb98189db5b037a186c87091f5 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Mon, 26 Apr 2021 09:06:25 -0700 |
| Subject: net:emac/emac-mac: Fix a use after free in emac_mac_tx_buf_send |
| |
| From: Lv Yunlong <lyl2019@mail.ustc.edu.cn> |
| |
| [ Upstream commit 6d72e7c767acbbdd44ebc7d89c6690b405b32b57 ] |
| |
| 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: b9b17debc69d2 ("net: emac: emac gigabit ethernet controller driver") |
| Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| drivers/net/ethernet/qualcomm/emac/emac-mac.c | 4 +++- |
| 1 file changed, 3 insertions(+), 1 deletion(-) |
| |
| diff --git a/drivers/net/ethernet/qualcomm/emac/emac-mac.c b/drivers/net/ethernet/qualcomm/emac/emac-mac.c |
| index 117188e3c7de..87b8c032195d 100644 |
| --- a/drivers/net/ethernet/qualcomm/emac/emac-mac.c |
| +++ b/drivers/net/ethernet/qualcomm/emac/emac-mac.c |
| @@ -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, |
| -- |
| 2.30.2 |
| |