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. This change silences the KMSAN report and prevents potential information leaks from the kernel memory. This fix has been tested and validated by syzbot. This patch closes the bug reported at the following syzkaller link and ensures no infoleak. Reported-by: syzbot+0c85cae3350b7d486aee@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=0c85cae3350b7d486aee Tested-by: syzbot+0c85cae3350b7d486aee@syzkaller.appspotmail.com Fixes: ef6980b6becb ("introduce IFE action") Signed-off-by: Ranganath V N --- 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. --- net/sched/act_ife.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/net/sched/act_ife.c b/net/sched/act_ife.c index 107c6d83dc5c..608ef6cc2224 100644 --- a/net/sched/act_ife.c +++ b/net/sched/act_ife.c @@ -644,13 +644,16 @@ static int tcf_ife_dump(struct sk_buff *skb, struct tc_action *a, int bind, unsigned char *b = skb_tail_pointer(skb); struct tcf_ife_info *ife = to_ife(a); struct tcf_ife_params *p; - struct tc_ife opt = { - .index = ife->tcf_index, - .refcnt = refcount_read(&ife->tcf_refcnt) - ref, - .bindcnt = atomic_read(&ife->tcf_bindcnt) - bind, - }; + struct tc_ife opt; struct tcf_t t; + memset(&opt, 0, sizeof(opt)); + memset(&t, 0, sizeof(t)); + + opt.index = ife->tcf_index, + opt.refcnt = refcount_read(&ife->tcf_refcnt) - ref, + opt.bindcnt = atomic_read(&ife->tcf_bindcnt) - bind, + spin_lock_bh(&ife->tcf_lock); opt.action = ife->tcf_action; p = rcu_dereference_protected(ife->params, --- base-commit: d127176862a93c4b3216bda533d2bee170af5e71 change-id: 20251031-infoleak-8a7de6afc987 Best regards, -- Ranganath V N