On Mon, Jun 2, 2025 at 7:37 PM Kees Cook [off-list ref] wrote:

On June 2, 2025 6:59:32 AM PDT, Pranav Tyagi [off-list ref] 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

There no need for the ifdef. Also these traditionally go at the end, between } and ;. See other examples in the tree.

-Kees

Thanks for the feedback. I will update the patch accordingly.

quoted

      /* Cacheline organization can be found documented in
       * Documentation/networking/net_cachelines/net_device.rst.
       * Please update the document when adding new fields.

--
Kees Cook