Thread (2 messages) 2 messages, 2 authors, 2021-06-19

[PATCH] net: ethernet: aeroflex: fix UAF in greth_of_remove

STALE1934d

From: Pavel Skripkin <hidden>
Date: 2021-06-18 14:58:15
Also in: linux-kernel-mentees, lkml
Subsystem: greth 10/100/1g ethernet mac device driver, networking drivers, the rest · Maintainers: Andreas Larsson, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds

static int greth_of_remove(struct platform_device *of_dev)
{
...
	struct greth_private *greth = netdev_priv(ndev);
...
	unregister_netdev(ndev);
	free_netdev(ndev);

	of_iounmap(&of_dev->resource[0], greth->regs, resource_size(&of_dev->resource[0]));
...
}

greth is netdev private data, but it is used
after free_netdev(). It can cause use-after-free when accessing greth
pointer. So, fix it by moving free_netdev() after of_iounmap()
call.

Fixes: d4c41139df6e ("net: Add Aeroflex Gaisler 10/100/1G Ethernet MAC driver")
Signed-off-by: Pavel Skripkin <redacted>
---
 drivers/net/ethernet/aeroflex/greth.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/aeroflex/greth.c b/drivers/net/ethernet/aeroflex/greth.c
index d77fafbc1530..c560ad06f0be 100644
--- a/drivers/net/ethernet/aeroflex/greth.c
+++ b/drivers/net/ethernet/aeroflex/greth.c
@@ -1539,10 +1539,11 @@ static int greth_of_remove(struct platform_device *of_dev)
 	mdiobus_unregister(greth->mdio);
 
 	unregister_netdev(ndev);
-	free_netdev(ndev);
 
 	of_iounmap(&of_dev->resource[0], greth->regs, resource_size(&of_dev->resource[0]));
 
+	free_netdev(ndev);
+
 	return 0;
 }
 
-- 
2.32.0
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