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authorNathan Chancellor <nathan@kernel.org>2023-12-06 09:49:46 -0700
committerRichard Weinberger <richard@nod.at>2024-01-05 00:23:14 +0100
commit7d748f60a4b82b50bf25fad1bd42d33f049f76aa (patch)
treebbda9f4de6571a955c3b93cdc7dfc2de755f998c /arch/um/drivers
parent7b84543cbd8861c83a2ec7c8848e936ce214bc01 (diff)
um: net: Fix return type of uml_net_start_xmit()
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 warning in clang aims to catch these at compile time, which reveals: arch/um/drivers/net_kern.c:353:21: warning: 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 *)' [-Wincompatible-function-pointer-types-strict] 353 | .ndo_start_xmit = uml_net_start_xmit, | ^~~~~~~~~~~~~~~~~~ 1 warning generated. ->ndo_start_xmit() in 'struct net_device_ops' expects a return type of 'netdev_tx_t', not 'int'. Adjust the return type of uml_net_start_xmit() to match the prototype's to resolve the warning. While UML does not currently implement support for kCFI, it could in the future, which means this warning becomes a fatal CFI failure at run time. Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202310031340.v1vPh207-lkp@intel.com/ Acked-by: Anton Ivanov <anton.ivanov@cambridgegreys.com> Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Richard Weinberger <richard@nod.at>
Diffstat (limited to 'arch/um/drivers')
-rw-r--r--arch/um/drivers/net_kern.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/um/drivers/net_kern.c b/arch/um/drivers/net_kern.c
index 3d7836c46507..cabcc501b448 100644
--- a/arch/um/drivers/net_kern.c
+++ b/arch/um/drivers/net_kern.c
@@ -204,7 +204,7 @@ static int uml_net_close(struct net_device *dev)
return 0;
}
-static int uml_net_start_xmit(struct sk_buff *skb, struct net_device *dev)
+static netdev_tx_t uml_net_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct uml_net_private *lp = netdev_priv(dev);
unsigned long flags;