[PATCH] epic100: fix use after free on rmmod

From: Tong Zhang
Date: Thu Jun 23 2022 - 03:40:29 EST


epic_close() calls epic_rx() and uses dma buffer, but in epic_remove_one()
we already freed the dma buffer. To fix this issue, reorder function calls
like in the .probe function.

BUG: KASAN: use-after-free in epic_rx+0xa6/0x7e0 [epic100]
Call Trace:
epic_rx+0xa6/0x7e0 [epic100]
epic_close+0xec/0x2f0 [epic100]
unregister_netdev+0x18/0x20
epic_remove_one+0xaa/0xf0 [epic100]

Fixes: ae150435b59e ("smsc: Move the SMC (SMSC) drivers")
Reported-by: Yilun Wu <yiluwu@xxxxxxxxxxxxxxxxx>
Signed-off-by: Tong Zhang <ztong0001@xxxxxxxxx>
---
drivers/net/ethernet/smsc/epic100.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/smsc/epic100.c b/drivers/net/ethernet/smsc/epic100.c
index a0654e88444c..0329caf63279 100644
--- a/drivers/net/ethernet/smsc/epic100.c
+++ b/drivers/net/ethernet/smsc/epic100.c
@@ -1515,14 +1515,14 @@ static void epic_remove_one(struct pci_dev *pdev)
struct net_device *dev = pci_get_drvdata(pdev);
struct epic_private *ep = netdev_priv(dev);

+ unregister_netdev(dev);
dma_free_coherent(&pdev->dev, TX_TOTAL_SIZE, ep->tx_ring,
ep->tx_ring_dma);
dma_free_coherent(&pdev->dev, RX_TOTAL_SIZE, ep->rx_ring,
ep->rx_ring_dma);
- unregister_netdev(dev);
pci_iounmap(pdev, ep->ioaddr);
- pci_release_regions(pdev);
free_netdev(dev);
+ pci_release_regions(pdev);
pci_disable_device(pdev);
/* pci_power_off(pdev, -1); */
}
--
2.25.1