Re: [PATCH v2 0/2] net: sched: act_ife: initialize struct tc_ife to fix KMSAN kernel-infoleak

[Simon Horman]

On Sat, Nov 01, 2025 at 06:04:46PM +0530, Ranganath V N wrote:
> Fix a KMSAN kernel-infoleak detected  by the syzbot .
> 
> [net?] KMSAN: kernel-infoleak in __skb_datagram_iter
> 
> In tcf_ife_dump(), the variable 'opt' was partially initialized using a
> designatied initializer. While the padding bytes are reamined
> uninitialized. nla_put() copies the entire structure into a
> netlink message, these uninitialized bytes leaked to userspace.
> 
> Initialize the structure with memset before assigning its fields
> to ensure all members and padding are cleared prior to beign copied.

Perhaps not important, but this seems to only describe patch 1/2.

> 
> Signed-off-by: Ranganath V N <vnranganath.20@xxxxxxxxx>

Sorry for not looking more carefully at v1.

The presence of this padding seems pretty subtle to me.
And while I agree that your change fixes the problem described.
I wonder if it would be better to make things more obvious
by adding a 2-byte pad member to the structures involved.

...