This is a note to let you know that I've just added the patch titled
net: ethernet: ti: Fix return type of netcp_ndo_start_xmit()
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-ethernet-ti-fix-return-type-of-netcp_ndo_start_x.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit abc7429706d14ed6e742eb1e2dda29b4c6fc47c8
Author: Nathan Chancellor <nathan@xxxxxxxxxx>
Date: Wed Nov 2 09:09:33 2022 -0700
net: ethernet: ti: Fix return type of netcp_ndo_start_xmit()
[ Upstream commit 63fe6ff674a96cfcfc0fa8df1051a27aa31c70b4 ]
With clang's kernel control flow integrity (kCFI, CONFIG_CFI_CLANG),
indirect call targets are validated against the expected function
pointer prototype to make sure the call target is valid to help mitigate
ROP attacks. If they are not identical, there is a failure at run time,
which manifests as either a kernel panic or thread getting killed. A
proposed warning in clang aims to catch these at compile time, which
reveals:
drivers/net/ethernet/ti/netcp_core.c:1944:21: error: incompatible function pointer types initializing 'netdev_tx_t (*)(struct sk_buff *, struct net_device *)' (aka 'enum netdev_tx (*)(struct sk_buff *, struct net_device *)') with an expression of type 'int (struct sk_buff *, struct net_device *)' [-Werror,-Wincompatible-function-pointer-types-strict]
.ndo_start_xmit = netcp_ndo_start_xmit,
^~~~~~~~~~~~~~~~~~~~
1 error generated.
->ndo_start_xmit() in 'struct net_device_ops' expects a return type of
'netdev_tx_t', not 'int'. Adjust the return type of
netcp_ndo_start_xmit() to match the prototype's to resolve the warning
and CFI failure.
Link: https://github.com/ClangBuiltLinux/linux/issues/1750
Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20221102160933.1601260-1-nathan@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/ethernet/ti/netcp_core.c b/drivers/net/ethernet/ti/netcp_core.c
index c17967b23d3c..957701d48712 100644
--- a/drivers/net/ethernet/ti/netcp_core.c
+++ b/drivers/net/ethernet/ti/netcp_core.c
@@ -1237,7 +1237,7 @@ static int netcp_tx_submit_skb(struct netcp_intf *netcp,
}
/* Submit the packet */
-static int netcp_ndo_start_xmit(struct sk_buff *skb, struct net_device *ndev)
+static netdev_tx_t netcp_ndo_start_xmit(struct sk_buff *skb, struct net_device *ndev)
{
struct netcp_intf *netcp = netdev_priv(ndev);
int subqueue = skb_get_queue_mapping(skb);
