[PATCH] net/qlcnic: fix possible use-after-free bugs in qlcnic_alloc_rx_skb()

[Ma Ke]

In qlcnic_alloc_rx_skb(), when dma_map_single() fails, skb is freed
immediately. And skb could be freed again. This issue could allow a
local attacker to crash the system due to a use-after-free flaw.

Signed-off-by: Ma Ke <make_ruc2021@xxxxxxx>
---
 drivers/net/ethernet/qlogic/qlcnic/qlcnic_io.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_io.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_io.c
index 41894d154013..6501aaf2b5ce 100644
--- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_io.c
+++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_io.c
@@ -832,6 +832,7 @@ static int qlcnic_alloc_rx_skb(struct qlcnic_adapter *adapter,
 	if (dma_mapping_error(&pdev->dev, dma)) {
 		adapter->stats.rx_dma_map_error++;
 		dev_kfree_skb_any(skb);
+		skb = NULL;
 		return -ENOMEM;
 	}
 
-- 
2.37.2