On Mon, Jun 2, 2025 at 8:50 PM Greg KH [off-list ref] wrote:

On Mon, Jun 02, 2025 at 07:29:32PM +0530, Pranav Tyagi wrote:

quoted

Add __randomize_layout to struct net_device to support structure layout
randomization if CONFIG_RANDSTRUCT is enabled else the macro expands to
do nothing. This enhances kernel protection by making it harder to
predict the memory layout of this structure.

Link: https://github.com/KSPP/linux/issues/188
Signed-off-by: Pranav Tyagi <redacted>
---
 include/linux/netdevice.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 7ea022750e4e..0caff664ef3a 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h

@@ -2077,7 +2077,11 @@ enum netdev_reg_state {
  *   moves out.
  */

+#ifdef CONFIG_RANDSTRUCT
+struct __randomize_layout net_device {
+#else
 struct net_device {
+#endif

Are you sure the #ifdef is needed?

thanks,

greg k-h

Hi Greg,

No, the #ifdef is not required since __randomize_layout is defined
as a no-op when CONFIG_RANDSTRUCT is disabled.
I rechecked the documentation to confirm this.
Thanks for pointing it out!
I will remove the #ifdef and update the patch before resending.

Regards
Pranav Tyagi