linux/drivers/s390
Nathan Chancellor bb16db8393 s390/lcs: Fix return type of lcs_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
proposed warning in clang aims to catch these at compile time, which
reveals:

  drivers/s390/net/lcs.c:2090:21: 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         = lcs_start_xmit,
                                    ^~~~~~~~~~~~~~
  drivers/s390/net/lcs.c:2097:21: 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         = lcs_start_xmit,
                                    ^~~~~~~~~~~~~~

->ndo_start_xmit() in 'struct net_device_ops' expects a return type of
'netdev_tx_t', not 'int'. Adjust the return type of lcs_start_xmit() to
match the prototype's to resolve the warning and potential CFI failure,
should s390 select ARCH_SUPPORTS_CFI_CLANG in the future.

Link: https://github.com/ClangBuiltLinux/linux/issues/1750
Reviewed-by: Alexandra Winter <wintera@linux.ibm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-11-07 11:24:37 +00:00
..
block s390 updates for the 6.1 merge window 2022-10-09 13:51:40 -07:00
char s390/vmur: generate uevent on unsolicited device end 2022-10-10 10:15:10 +02:00
cio s390/cio: fix out-of-bounds access on cio_ignore free 2022-10-26 14:47:31 +02:00
crypto s390/vfio-ap: Fix memory allocation for mdev_types array 2022-10-26 14:47:31 +02:00
net s390/lcs: Fix return type of lcs_start_xmit() 2022-11-07 11:24:37 +00:00
scsi s390: move from strlcpy with unused retval to strscpy 2022-08-30 22:00:33 +02:00
virtio virtio: Revert "virtio: find_vqs() add arg sizes" 2022-08-16 01:40:24 -04:00
Makefile s390: remove pointless drivers-y in drivers/s390/Makefile 2019-09-16 13:21:51 +02:00