Commit 45605c75 authored by Wang Hai's avatar Wang Hai Committed by Tony Nguyen
Browse files

e100: Fix possible use after free in e100_xmit_prepare 



In e100_xmit_prepare(), if we can't map the skb, then return -ENOMEM, so
e100_xmit_frame() will return NETDEV_TX_BUSY and the upper layer will
resend the skb. But the skb is already freed, which will cause UAF bug
when the upper layer resends the skb.

Remove the harmful free.

Fixes: 5e5d4942 ("e100: Release skb when DMA mapping is failed in e100_xmit_prepare")
Signed-off-by: default avatarWang Hai <wanghai38@huawei.com>
Reviewed-by: default avatarAlexander Duyck <alexanderduyck@fb.com>
Signed-off-by: default avatarTony Nguyen <anthony.l.nguyen@intel.com>
parent 227d8d2f

drivers/net/ethernet/intel/e100.c

+1 −4
Original line number Diff line number Diff line
@@ -1741,11 +1741,8 @@ static int e100_xmit_prepare(struct nic *nic, struct cb *cb, 
	dma_addr = dma_map_single(&nic->pdev->dev, skb->data, skb->len,

				  DMA_TO_DEVICE);

	/* If we can't map the skb, have the upper layer try later */

	if (dma_mapping_error(&nic->pdev->dev, dma_addr)) {

		dev_kfree_skb_any(skb);

		skb = NULL;

	if (dma_mapping_error(&nic->pdev->dev, dma_addr))

		return -ENOMEM;

	}



	/*

	 * Use the last 4 bytes of the SKB payload packet as the CRC, used for